Presbyopia: Symptoms, causes and treatment

Presbyopia is the normal loss of near focusing ability that occurs with age. Most people begin to notice the effects of presbyopia sometime after age 40, when they start having trouble seeing small print clearly — including text messages on their phone.

You can’t escape presbyopia, even if you’ve never had a vision problem before. Even people who are short sighted will notice that their near vision blurs when they wear their usual spectacles or contact lenses to correct distance vision.

The eye’s lens stiffens with age, so it is less able to focus when you view something up close.

 

Researchers estimate that nearly 2 billion people worldwide have presbyopia.

Though presbyopia is a normal change in our eyes as we age, it often is a significant and emotional event because it’s a sign of ageing that’s impossible to ignore and difficult to hide.

In parts of the world where there is no access to vision care, presbyopia is much more than an inconvenience — it’s a leading cause of vision impairment that reduces people’s quality of life and productivity.

Presbyopia symptoms

When you become presbyopic, you either have to hold your mobile phone and other objects and reading material (books, magazines, menus, labels, etc.) further away from your eyes to see them more clearly.

Unfortunately, when we move things further away from our eyes they get smaller in size, so this is only a temporary and partially successful solution to presbyopia.

If you can still see close objects pretty well, presbyopia can cause headaches, eye strain and visual fatigue that makes reading and other near vision tasks less comfortable and more tiring.

What causes presbyopia?

Presbyopia is an age-related process. It is a gradual thickening and loss of flexibility of the natural lens inside your eye.

These age-related changes occur within the proteins in the lens, making the lens harder and less elastic over time. Age-related changes also take place in the muscle fibres surrounding the lens. With less elasticity, it gets difficult for the eyes to focus on close objects.

Presbyopia treatment

Presbyopia can be treated with spectacles (including reading glasses), contact lenses and vision surgery.

Spectacles

Spectacles with progressive lenses are the most popular solution for presbyopia for most people over age 40. These line-free multifocal lenses restore clear near vision and provide excellent vision at all distances.

Another presbyopia treatment option is spectacles with bifocal lenses, but bifocals provide a more limited range of vision for many people with presbyopia.

It’s also common for people with presbyopia to notice they are becoming more sensitive to light and glare due to ageing changes in their eyes. Photochromic lenses, which darken automatically in sunlight, are a good choice for this reason.

Reading glasses are another choice. Unlike bifocals and progressive lenses, which most people wear all day, reading glasses are worn only when needed to see close objects and small print more clearly.

If you wear contact lenses, your optician, can prescribe reading glasses that you wear while your contact lenses are in. You may purchase reading glasses at a retail shop, or you can get higher-quality versions prescribed by your optician.

Regardless which type of spectacles you choose to correct presbyopia, definitely consider lenses that include anti-reflective coating. Anti-reflective coating eliminates reflections that can be distracting and cause eye strain. It also helps reduce glare and increase visual clarity for night driving.

Contact lenses

People with presbyopia also can opt for multifocal contact lenses, available in gas permeable or soft lens materials.

Another type of contact lens correction for presbyopia is monovision, in which one eye wears a distance prescription, and the other wears a prescription for near vision. The brain learns to favour one eye or the other for different tasks.

While some people are delighted with this solution, others complain of reduced visual acuity and some loss of depth perception. Because the human eye changes as you grow older, your presbyopia glasses or contacts prescription will need to be increased over time as well. You can expect your optician to prescribe a stronger correction for near work as you need it.

Presbyopia surgery

If you don’t want to wear spectacles or contact lenses for presbyopia, a number of surgical options to treat presbyopia are available as well.

One presbyopia correction procedure that’s gaining popularity is implantation of a corneal inlay.

Typically implanted in the cornea of the eye that’s not your dominant eye, a corneal inlay increases depth of focus of the treated eye and reduces the need for reading glasses without significantly affecting the quality of your distance vision.

The first step to see if you are a good patient for presbyopia surgery is to have a comprehensive eye exam and a consultation with a refractive surgeon who specialises in the surgical correction of presbyopia.

Presbyopia is a part of growing older

Presbyopia is a normal part of the ageing process, and we’re all going to have to deal with it sometime after age 40. Whichever option you choose – spectacles, contact lenses or surgery – you’ll be able to easily read messages on your phone or a book to your granddaughter without any trouble.

If you are beginning to notice signs and symptoms of presbyopia, contact us for an eye exam and consultation regarding the best presbyopia treatment options for you.

Source: https://www.allaboutvision.com/en-gb/conditions/presbyopia/


Risks associated with eye-make up

Applying make-up is an everyday routine for millions of people worldwide. Even if a person only applies make-up once or twice a week, maintaining good make-up hygiene is essential in preventing skin irritations and serious eye infections.

How to practice good make-up hygiene

There are a number of simple but important steps that can help to prevent eye irritation and eye infections.

Renew your make-up every three months to reduce the risk of developing infections. This is particularly true in the case of eye make-up like mascaras or eyeliners. In some rare cases, women who have developed an eye infection from cosmetics have been temporarily or permanently blinded, according to the FDA. Some of these infections may stem from the make-up wands or brushes themselves.

 

Image Credit: Lucky Business / Shutterstock

Once a mascara wand or eyeliner brush comes into contact with the eyelashes, contamination of the applicator occurs as eyelashes naturally have bacteria on them. Over time, this contamination of both the brush and the container builds up and can lead to an increased risk of infection or allergic reactions. For this reason, sharing cosmetics is not advised at any time, as bacteria can harm another person even if the original user does not experience any reactions or infections themselves.

Fortunately, most people won’t experience any problems using make-up for longer than three months. If irritation does occur after using make-up products, it is essential to stop using the product immediately. If the irritation persists, medical attention should be sought.

Storing make-up products properly is also important. If cosmetics are stored in particularly hot conditions, for instance above 85°F (29°C), the preservatives in the products are at a higher risk of deteriorating.

Risks associated with eye-make up

It is important to remove make-up before sleeping. Ophthalmologist Dana Robaei published a case study in 2018 about a woman suffering from chronic foreign body sensation in both of her eyes. The article detailed the harmful effects that can occur after leaving mascara on overnight.

After examining the eyes, Robaei found subconjunctival mascara deposition beneath both eyelids. This was due to over 25 years of heavy mascara use without taking care to remove it properly. Small pieces of mascara had built up inside the eyelid and formed into solid concretions that were scratching the cornea, resulting in irritation and discomfort. The patient was left with permanent scarring on the cornea and on the eyelid after a surgical procedure to remove the built up concretions. Although Robaei clarifies it was a rare and extreme case, it nevertheless highlights the importance of removing eye make-up properly every night.

Other reports have been made about the risk of mascara-induced damage to the lacrimal drainage system, with one patient developing a dacryolith (a concretion usually comprising lipids, epithelial cells and other debris) loaded with mascara. Other reports in literature reviews on problems caused by mascara include eyelid dermatitis, infection keratitis, and mascaroma, among others.

Additionally, not all make-up applied to the eyes remains within the area of application. For instance, mascara can flake off and small particles travel into the eye, causing redness or irritation. In other cases, the eye can be scratched by make-up brushes or pencils that can then lead to serious eye infections. Ensuring that any applicator used near the eyes is clean can help to reduce the risk of scratch-induced infections. However, the trauma caused by scratches may still trigger problems or reactions.

Summary

As most make-up and cosmetic products undergo rigorous testing before being sold, the daily use of make-up is thought to pose minimal initial risk. It is when make-up is not removed properly, contaminated, or used when individual allergies are already apparent, that risks of infection, irritation and permanent damage to the application area increase.

A microbial study asked forty women to use one of two brands of non-waterproof mascara every day for three months. It was found that out of the 33 samples collected from the 40 women, microbial growth was present in over 36% of mascara containers.

As such, the need to practice good make-up hygiene is clear. Careful application of make-up around the eyes can reduce the risk of eye injury and subsequent irritation, infection, and loss of vision, in rare cases.

Sources

https://www.news-medical.net/health/Risks-Associated-with-Eye-Make-Up.aspx
http://www.scielo.br/pdf/abo/v79n6/0004-2749-abo-79-06-0411.pdf
journals.lww.com/…/…anifestations_of_Long_Term_Mascara_Use.29.aspx
https://wexnermedical.osu.edu/blog/eye-makeup-risks
https://www.aaojournal.org/article/S0161-6420(17)33788-0/fulltext
https://www.ajo.com/article/0002-9394(75)90798-9/pdf
www.sciencealert.com/mascara-make-up-remove-health-effects-dangerous-eyes
https://www.sciencedirect.com/science/article/pii/S1529183908003795


Eye spots, floaters and flashes

Vitreous detachment and floaters within the eye

Eye floaters are those tiny spots, specks, flecks and “cobwebs” that drift aimlessly around in your field of vision. While annoying, ordinary eye floaters and spots are very common and usually aren’t cause for alarm.

Floaters and spots typically appear when tiny pieces of the eye’s gel-like vitreous break loose within the inner back portion of the eye.

At birth and throughout childhood, the vitreous has a gel-like consistency. But as we age, the vitreous begins to dissolve and liquefy to create a watery centre.

Some undissolved gel particles occasionally will float around in the more liquid centre of the vitreous. These particles can take on many shapes and sizes to become what we refer to as “eye floaters.”

You’ll notice that these spots and eye floaters are particularly pronounced if you gaze at a clear or overcast sky or a computer screen with a white or light-coloured background. You won’t actually be able to see tiny bits of debris floating loose within your eye. Instead, shadows from these floaters are cast on the retina as light passes through the eye, and those tiny shadows are what you see.

You’ll also notice that these specks never seem to stay still when you try to focus on them. Floaters and spots move when your eye and the vitreous gel inside the eye moves, creating the impression that they are “drifting.”

When are eye floaters and flashes a medical emergency?

Noticing a few floaters from time to time is not a cause for concern. However, if you see a shower of floaters and spots, especially if they are accompanied by flashes of light, you should seek medical attention immediately from an optician.

The sudden appearance of these symptoms could mean that the vitreous is pulling away from your retina — a condition called posterior vitreous detachment.

Or it could mean that the retina itself is becoming dislodged from the back of the eye’s inner lining, which contains blood, nutrients and oxygen vital to healthy function. As the vitreous gel tugs on the delicate retina, it might cause a small tear or hole in it. When the retina is torn, vitreous can enter the opening and push the retina farther away from the inner lining of the back of the eye — leading to a retinal detachment.

A detached retina is a medical emergency that requires immediate treatment to prevent permanent vision loss. Treatment consists of surgery to reattach the retina to the back surface of the eyeball, reconnecting it to its source of blood, oxygen and other nutrients.

Posterior vitreous detachments (PVDs) are far more common than retinal detachments and often are not an emergency even when floaters appear suddenly. Some vitreous detachments also can damage the retina by tugging on it, leading to a tear or detachment of a portion of the retina.

What causes eye floaters and spots?

As mentioned above, PVDs are common causes of vitreous floaters, and retinal tears and detachments also can contribute to floaters and spots.

What leads to vitreous detachments in the first place?

As the eye develops, the vitreous gel fills the inside of the back of the eye and presses against the retina and attaches to the surface of the retina. Over time, the vitreous becomes more liquefied in the centre. This sometimes means that the central, more watery vitreous cannot support the weight of the heavier, more peripheral vitreous gel. The peripheral vitreous gel then collapses into the central, liquefied vitreous, detaching from the retina.

It’s estimated that more than half of all people will have a PVD by age 80. Thankfully, most of these vitreous detachments do not lead to a torn or detached retina.

Light flashes during this process mean that traction is being applied to your retina while the PVD takes place. Once the vitreous actually detaches from the retina this traction pressure is eased, and the light flashes should subside.

What causes eye flashes?

Ordinarily, light entering your eye stimulates the retina. This produces an electrical impulse, which the optic nerve transmits to the brain. The brain then interprets this impulse as light or some type of image.

If the retina is mechanically stimulated (physically touched or tugged), a similar electrical impulse is sent to the brain. This impulse is then interpreted as a flash or flicker of light called a photopsia.

When the retina is tugged, torn or detached from the back of the eye, a flash or flicker of light commonly is noticed. Depending on the extent of the traction, tear or detachment, these photopsias might be short-lived or continue indefinitely until the retina is repaired.

Photopsias also may occur after a blow to the head that is capable of shaking the vitreous gel inside the eye. When this occurs, the phenomenon sometimes is called “seeing stars.” In some cases, photopsias are associated with migraine headaches and ocular migraines.

Other conditions associated with eye floaters and flashes

When a PVD is accompanied by bleeding inside the eye (vitreous hemorrhage), it means the traction that occurred may have torn a small blood vessel in the retina.

A vitreous hemorrhage increases the possibility of a retinal tear or detachment. Traction exerted on the retina during a PVD also can lead to development of conditions such as macular holes or puckers.

Vitreous detachments with accompanying eye floaters also may occur in circumstances such as:

  • Inflammation in the eye’s interior
  • Short sightedness
  • Cataract surgery
  • YAG laser eye surgery
  • Diabetes (diabetic vitreopathy)
  • CMV retinitis

Inflammation associated with many conditions such as eye infections can cause the vitreous to liquefy, leading to a PVD.

When you are shortsighted, your eye’s elongated shape also can increase the likelihood of a PVD and accompanying traction on the retina. Shortsighted people also are more likely to have PVDs at a younger age.

PVDs are very common following cataract surgery and a follow-up procedure called a YAG laser capsulotomy.

Months or even years after cataract surgery, it’s not unusual for the thin membrane (or “capsule”) that’s left intact behind the interocular lens (IOL) to become cloudy, affecting vision. This delayed cataract surgery complication is called posterior capsular opacification (PCO).

In the capsulotomy procedure used to treat PCO, a special type of laser focuses energy onto the cloudy capsule, vaporising the central portion of it to create a clear path for light to reach the retina, which restores clear vision.

Manipulations of the eye during cataract surgery and YAG laser capsulotomy procedures cause traction that can lead to posterior vitreous detachments.

How to get rid of eye floaters

Most eye floaters and spots are harmless and merely annoying. Many will fade over time and become less bothersome. In most cases, no eye floaters treatment is required.

However, large persistent floaters can be very bothersome to some people, causing them to seek a way to get rid of eye floaters and spots drifting in their field of view.

But the risks of a virectomy usually outweigh the benefits for eye floater treatment. These risks include surgically induced retinal detachment and serious eye infections. On rare occasions, vitrectomy surgery can cause new or even more floaters. For these reasons, most eye surgeons do not recommend vitrectomy to treat eye floaters and spots.

Laser treatment for floaters

A relatively new laser procedure called laser vitreolysis has been introduced that is a much safer alternative to vitrectomy for eye floater treatment.

In this in-office procedure, a laser beam is projected into the eye through the pupil and is focused on large floaters, which breaks them apart and/or frequently vaporises them so they disappear or become much less bothersome.

To determine if you can benefit from laser vitreolysis to get rid of eye floaters, your optician will consider several factors, including your age, how quickly your symptoms started, what your floaters look like and where they are located.

Many floaters in patients younger than age 45 may be located too close to the retina and can’t be safely treated with laser vitreolysis. Patients with sizable eye floaters located farther away from the retina are better suited to the procedure.

An ophthalmologist who performs laser vitreolysis also will evaluate the shape and borders of your eye floaters. Those with “soft” borders often can be treated successfully. Likewise, sizable floaters that appear suddenly as a result of a posterior vitreous detachment often can be successfully treated with the laser procedure.

What happens during laser vitreolysis

Laser vitreolysis usually is pain-free and can be performed in an eye surgeon’s office. Just prior to the treatment, anesthetic eye drops are applied, and a special type of contact lens is placed on your eye. Then, the surgeon will look through a medical device and deliver the laser energy to the floaters being treated.

During the procedure, you might notice dark spots. These are pieces of broken up floaters. The treatment can take up to a half hour, but it’s usually significantly shorter.

At the end of the procedure, the contact lens is removed, your eye is rinsed with saline and the surgeon will apply an anti-inflammatory eye drop. Additional eye drops may be prescribed for you to use at home.

Sometimes, you may see small dark spots shortly after treatment. These are small gas bubbles that tend to resolve quickly. There also is a chance that you’ll have some mild discomfort, redness or blurry vision immediately after the procedure. These effects are common and typically won’t prevent you from returning to your normal activities immediately following laser vitreolysis.

If you are bothered by large, persistent eye floaters, ask your optician if laser vitreolysis might be a good treatment option for you.

Remember, a sudden appearance of a significant number of eye floaters, especially if they are accompanied by flashes of light or other vision disturbances, could indicate a detached retina or other serious problem in the eye. If you suddenly see new floaters, visit your optician without delay.

 

Source: allboutvision.com

By Marilyn Haddrill; contributions and review by Charles Slonim, MD


Could Glasses Protect Against COVID-19?

Wearing spectacles may lower your chances of contracting the coronavirus, according to a new study from Hubei Province, China. The findings appeared in JAMA Ophthalmology, a medical journal. But does this mean everyone should wear eye protection to prevent COVID-19? Not exactly, says ophthalmologist Thomas Steinemann, MD, clinical spokesperson for the American Academy of Ophthalmology and a professor of ophthalmology at MetroHealth Medical Center.

Ophthalmologists say there’s not enough information to recommend that people start wearing eye protection in addition to masks.

“It’s a provocative and fascinating study. But in the scheme of things, this is a small portion of the population. We’d require a much larger study before making any conclusions about whether wearing glasses really does mean people are touching their eyes less often, and therefore decreasing infection rates,” Dr. Steinemann said.

Coronavirus can spread through the eyes when an infected person coughs or sneezes near your eye or if you touch an infected object before touching your eye.

A possible link between spectacles and the coronavirus

The study came from a curious observation made by researchers in China. They noticed that very few of their sick patients wore glasses, which was remarkable since nearsightedness is common in China. They examined hospital records from patients with Covid-19 to learn more. Of 276 patients admitted to the hospital over a 47-day period, only 16 patients (5.8%) had myopia or nearsightedness that required them to wear glasses for more than eight hours a day.

Earlier research shows that more than 30% of people in the region needed glasses for nearsightedness.

Dr. Steinemann says it could be that glasses serve as a reminder to avoid touching your eyes. It may also be that glasses act as a partial barrier, protecting eyes from the splatter of a cough or sneeze. There are several factors other than wearing glasses that could explain the study’s finding. It could be that people who wear glasses tend to be older and more likely to stay home during the pandemic, compared with people who do not wear glasses. Or maybe people who can afford glasses in China are less likely to contract the virus because they can afford to live in less-crowded spaces.

Should you wear eye protection to prevent COVID-19?

While it’s too soon to say everyone should wear eye protection, Dr. Steinemann said that wearing goggles or face shields does make sense for frontline health care workers and people who care for those with the virus. For the rest of us, wearing a mask, frequent hand washing and practicing social distancing continue to be our best bet against the virus.

Source: www.aao.org/eye-health/news/eyeglasses-protect-against-covid-19-coronavirus


Eye Health and Diet

Healthy vision is important in ensuring quality of life. Two common threats to aging eyes are cataracts and age-related macular degeneration (AMD) which can, however, be prevented to some extent by a good diet.

Close up of the senile cataract during eye examination, senile cataract, mature cataract, neuclear sclerosis cataract. Image Credit: ARZTSAMUI / Shutterstock

 

Some important nutrients are found in common foods, and including them in the daily diet will help to preserve good vision throughout life. Antioxidants protect tissues from the toxic effects of free radicals which lead to a breakdown of cell membranes and nucleic acids. Free radicals are formed when tissue is exposed to ultraviolet radiation as from direct sunlight, in cigarette smoke, and other air pollutants. The retina is exposed to a lot of light and is therefore a prime spot for free radical damage, which makes it all the more important to provide antioxidants that reduce the high level of oxidative stress.

Specific Nutrients

Lutein and zeaxanthin: Found in spinach and kale, as well as other green leafy vegetables, and also eggs, these powerful antioxidants, which are typically found together in food, are known to reduce the risk of AMD as well as cataracts. They enter the retina and the lens and prevent degenerative changes, absorbing light frequencies such as blue and ultraviolet frequencies, which promote free radical formation, especially the vulnerable macular area. Other sources include kiwis, grapes, collard greens, and broccoli.

Lutein and zeaxanthin foods, info graphic food, fruit and vegetable icon vector. Image Credit: Plalek / Shutterstock

Vitamin C or ascorbic acid is found in fruits and vegetables, and may reduce the risk of cataracts. AMD may also be slowed if vitamin C and other nutritional factors are taken in combination. Vitamin C is found in grapefruit, strawberries, Brussels sprouts, ripe papayas, oranges, and green peppers.

Vitamin E or alpha-tocoferol is another powerful antioxidant found in nuts, sweet potatoes, and fortified cereals. It is also found in sunflower seeds, wheat germ oil, and vegetable oils.

Essential fatty acids: these fats are not synthesized in the human body but are required for the proper health and functioning of the nervous system, for energy metabolism and immunity. Among these, omega-3 fatty acids like DHA (docosahexaenoic acid) are vital for retinal function and for the development of vision, being concentrated in the outer parts of the photoreceptor cells. These are anti-inflammatory agents, which helps to prevent AMD. These fatty acids are found in salmon, herring and sardines, as well as tuna, halibut and flounder. Two servings or more a week are advised.

Zinc: this trace mineral is a cofactor in the transport of vitamin A from its storage site in the liver to the retina, where it is converted to melanin. This black pigment is essential in protecting retinal tissues against photodamage. High concentrations of zinc are present in the retina and the choroidal vascular tissue under the retina. Zinc is found in white meats from turkey, oysters, and crab meat, as well as eggs, peanuts, whole grains, and red meats.

Beta carotene which is found in all vegetables and fruits that are deep yellow or orange is part of the essential visual pigments, and its deficiency causes night blindness. Pumpkins, red peppers, kale, carrots, sweet potatoes and winter squash are all prime sources.

Supplements – Do They Play a Role?

AMD may be prevented or slowed using supplements made to AREDS standards. AREDS stands for the pivotal Age-Related Eye Disease Studies which tested the formula of this mix of antioxidants clinically. The current AREDS 2 version contains more lutein and zeaxanthin than before, which covers any dietary deficiency. Unlike many other supplements, it does not have beta-carotene and is therefore safe for smokers or those who have just quit. In this subgroup, this nutrient could cause a higher risk of lung cancer, though only at very high doses.

While no research suggests exactly how much of each of these nutrients is necessary to keep vision in good working order, the good old rule of five or more servings of colorful fruits and vegetables every day, with fish at least twice a week, seems to be most helpful in preventing eye problems with age.

Sources
www.aoa.org/…/diet-and-nutrition
www.health.harvard.edu/…/top-foods-to-help-protect-your-vision
https://www.health.ny.gov/publications/0911/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3693724/
https://www.moorfields.nhs.uk/content/your-eye-health

Written by

Dr. Liji Thomas


What is astigmatism? What are correction options?

 

man experiencing eye strain

What is astigmatism?

Astigmatism is a type of refractive error caused by the irregularities in the shape of a person’s cornea. In this condition, the eye fails to focus the light equally on the retina leading to blurred or distorted vision. It can be present at the time of birth, or can develop gradually in life.

Astigmatism is a common eye condition which usually occurs with myopia (short-sightedness) or hyperopia (long-sightedness) and can be easily diagnosed with a simple eye exam.

Astigmatism is a refractive error and is not an eye disease or eye health issue.

Astigmatism is simply a problem with how the eye focuses light.

Astigmatism symptoms

Astigmatism usually causes vision to be blurred or distorted to some degree at all distances. Some of its symptoms are eye strain, headaches, squinting and eye irritation.

What causes astigmatism?

Astigmatism is usually caused by an irregularly shaped cornea. Instead of the cornea having a symmetrically round shape (like a football), it is shaped more like an egg (or rugby ball), with one meridian being significantly more curved than the meridian perpendicular to it.

(To understand what meridians are, think of the front of the eye like the face of a clock. A line connecting the 12 and 6 is one meridian; a line connecting the 3 and 9 is another.)

The steepest and flattest meridians of an eye with astigmatism are called the principal meridians.

In some cases, astigmatism is caused by the distortion of shape of the lens inside the eye. This is called lenticular astigmatism, to differentiate it from the more common corneal astigmatism.

It’s important to schedule an eye exam for your child to avoid vision problems in school from uncorrected astigmatism.

3 types of astigmatism
There are three primary types of astigmatism:

  • Myopic astigmatism.

One or both principal meridians of the eye are short sighted. (If both meridians are short sighted, they are myopic in differing degree.)

  • Hyperopic astigmatism.

One or both principal meridians are long sighted. (If both are long sighted, they are hyperopic in differing degree.)

  • Mixed astigmatism.

One prinicipal meridian is short sighted, and the other is long sighted.

Astigmatism is also classified as regular or irregular. In regular astigmatism, the principal meridians are 90 degrees apart (perpendicular to each other). In irregular astigmatism, the principal meridians are not perpendicular.

Most astigmatism is regular corneal astigmatism, which gives the front surface of the eye an oval shape.

Irregular astigmatism can result from an eye injury that has caused scarring on the cornea, from certain types of eye surgery or from keratoconus, a disease that causes a gradual thinning of the cornea.

Astigmatism tests

Astigmatism is detected during a routine eye exam with the same instruments and techniques used for the detection of short-sightedness and long-sightedness.

Your optician can estimate the amount of astigmatism you have by shining a light into your eye while manually introducing a series of lenses between the light and your eye. This test is called retinoscopy.

Astigmatism correction options

Astigmatism can usually be corrected with glasses or contact lenses.

Refractive surgery is one of the less common astigmatism correction options, however, since it is a laser procedure that changes the shape of your eyes, it comes with risks associated with most surgeries.

Astigmatism should be treated as soon as possible. Once diagnosed, regular visits to an optician are required as astigmatism can fluctuate over time, making it necessary for prescriptions to be modified.

Source: allaboutvision.com/en-gb/conditions/astigmatism/


Why face masks can make eyes feel dry, and what you can do about it

Face masks help reduce coronavirus transmission, which has prompted mandates and expert recommendations for their use where social distancing is difficult. As the world emerges from shutdowns, wearing face masks for extended periods of time in settings such as offices will increase.

While these protective measures are essential to combating COVID-19’s spread, a new phenomenon is emerging: increasing reports of dry, uncomfortable eyes. What is the science behind this trend, who is at risk and is there a solution?

Dry eye has become much better understood in recent years, thanks to colleagues from the Centre for Ocular Research & Education (CORE) at the University of Waterloo, the Tear Film and Ocular Surface Society and other researchers around the world. That knowledge provides a head start on deciphering this latest wrinkle.

Making sense of MADE: Mask-associated dry eye

The term mask-associated dry eye (MADE) was first described by an ophthalmologist in June based on increasing incidents in his office. Additional reports have since circulated, and a recent review further examined the issue.

People with existing dry eye disease report worsening symptoms — a problematic occurrence for the tens of millions of people worldwide who already struggle with the issue. Concurrently, previously asymptomatic patients are flagging uncomfortable eyes and variable vision for the first time, particularly when reading or using digital devices for a long period of time.

Our tear film’s delicate balance

When addressing MADE, it is helpful to understand our tear film, the liquid layer that coats the eye’s surface. This tiny volume of fluid, equivalent to one-tenth of a single water drop, has a highly complex structure and composition. It lubricates the surface of the eye, allowing smooth and comfortable passage of the eyelid during every blink. Ongoing imbalance in the tear film leads to dry eye disease.

Eyes feel sore, dry and irritated, and may water and look red.

A sore, irritated, uncomfortable dry eye. (Shutterstock)

There are many causes of dry eye disease, including issues relating to eye and systemic health conditions, age, gender or medications. Excessive use of digital devices, poor indoor air quality and pollution all result in symptoms. Situations that increase how quickly the tear film evaporates, such as air-conditioned offices or automobile air-blowers, can quickly and significantly dry the eye’s surface, leading to more pronounced symptoms.

Masks, airflow and evaporation

 

Face masks significantly reduce the spread of air outwards from the mouth and nose. However, exhaled air still needs to disperse; when a mask sits loosely against the face the likely route is upwards. This forces a stream of air over the surface of the eye, creating conditions that accelerate the evaporation of the tear film, like a steady breeze blowing over damp skin.

People who wear glasses are well aware of this, shown by the annoying lens fogging that often occurs when breathing under a mask.

Annoying, fogged-up spectacles due to a poor fitting mask. (Chau-Minh Phan/CORE, University of Waterloo), Author provided

When masks are worn for extended periods, this repeated evaporation may lead to dry spots on the ocular surface.

Similar effects have been reported with continuous positive airway pressure (CPAP) masks that are used to treat sleep apnea. Eye dryness may also result when face masks are taped to seal the top edge, if that interferes with the eyelids’ natural movement, preventing full blinks. Incomplete blinking can cause the tear film to become less stable.

Who may be affected?

In addition to those with pre-existing dry eye disease, the general mask-wearing population may find themselves wondering why their eyes are inexplicably irritated. This includes the elderly, who naturally have less efficient tears.

An extensive review demonstrated that wearing contact lenses does not raise the risk of contracting COVID-19, as long as people follow good hygiene and cleaning measures. However, a contact lens can disturb the tear film, potentially making wearers more MADE-susceptible if exhaled air further impacts tear film stability.

Prolonged use of face masks in air-conditioned locations may also trigger MADE. So too could increased digital device use while wearing masks — a rising trend during the pandemic.

Beyond discomfort, MADE presents another risk: it may encourage people to rub their face and eyes for temporary relief. Coronavirus transmission is possible via the mouth and nose, and, to a lesser extent, potentially the eyes. Bringing unwashed hands near the face may increase the likelihood of infection. That is an additional reason to tackle MADE.

Alleviating MADE
Several simple measures can help reduce the drying effects of upward air flow from masks.

Mask Associated Dry Eye (MADE): Why does it happen and what can you do? (Karen Walsh, CORE, University of Waterloo), Author provided

As with any new eye-related concern, first check with an eye care practitioner for advice and to rule out other causes.

Second, ensure that a mask is worn appropriately, particularly when wearing spectacles and sunglasses. A close-fitted mask, or carefully taped top edge that does not interfere with blinking, may help direct air flow downwards. This helps prevent lenses from steaming and reduces MADE.

Clear spectacles with a well fitting mask. (Chau-Minh Phan/CORE, University of Waterloo), Author provided

Lubricating drops may help with comfort. Eye care practitioners can recommend the best type, based on medical history and circumstances.

Limit time in air-conditioned or windy environments when wearing masks, and take regular breaks from digital devices.

Don’t ditch the mask

Is wearing a mask worth it, when you may have to possibly contend with MADE? Absolutely! Masks are here for the foreseeable future. Along with social distancing and hygiene measures, they represent a crucial part of our defence against the spread of COVID-19.

The good news is that we understand why MADE occurs and can address it. Remaining alert and following a few simple steps can help increase eye comfort and promote good mask wear, and with it, we move further along in overcoming the global pandemic.

Source:

conversation.com

Author
Lyndon Jones
Professor, School of Optometry & Vision Science, University of Waterloo


Wearing a face mask? Here are 6 ways to avoid foggy glasses

While face masks help us avoid unknowingly transmitting coronavirus, millions of eyeglass wearers are discovering the nuisance of mask-induced foggy lenses.

With the World Health Organization (WHO) now recommending the wearing of face masks to curb the spread of COVID-19, fogged-up glasses are a problem “affecting a large chunk of the population,” says Chicago optometrist Joanna Slusky, founder and CEO of Halsted Eye Boutique.

What can you do about your fogged-up glasses?

We have compiled seven tips for lifting the fog from your glasses when you’re wearing a mask, but first let’s go over why your lenses are fogging up in the first place.

Why are my glasses foggy?
Body heat and air flow lead to foggy lenses, explains optician Shannen Knight, owner of A Sight for Sport Eyes, an eyewear retailer based in West Linn, Oregon.

When you’re wearing a face mask, you repeatedly breathe out warm air. This air then can sneak out of the top of your mask and steam up the lenses of your glasses. Of course, this can make it difficult to see.

According to a study published in The Annals of The Royal College of Surgeons of England, a face mask directs much of the exhaled air upward.

The “misting” of lenses happens when warm water vapor from your breath lands on the cooler lenses, producing tiny droplets that scatter light and reduce the lenses’ ability to transmit contrast (when light colors remain light and dark colors remain dark).

“The droplets form because of the inherent surface tension between the water molecules,” the study’s authors said.

6 ways to avoid foggy glasses

Now that you know why your lenses fog up, let’s review seven ways to prevent this fog when you’re wearing glasses and a face mask.

  1.  Seal the mask

A common trick employed by doctors involves sticking a piece of double-sided tape across the bridge of the nose before putting on a mask, says Shaun Veran, co-founder of OURA. OURA’s wellness products include reusable, antibacterial face masks.

“If you place the double-sided tape between the inside of the mask and the bridge of your nose, it will create a better seal,” Veran says. “You can also place an additional piece of cellophane or masking tape over the mask as well.”

2. Make sure the mask fits well

A loose-fitting mask lets exhaled air head toward your glasses, but a snugly fitting mask can shoot that air out of the bottom or sides of the mask and away from your glasses.

For a better fit, Veran recommends looking for masks equipped with moldable pieces around the nose (such as a metal strip) or masks that come in various sizes.

“If the mask is well-fitted, it will dramatically help to prevent the amount of hot air that can reach the lenses,” Veran advises.

“Make sure that your face mask has a snug fit around the nose bridge,” he adds. “The more conformed the mask is around the bridge of your nose, the less of that hot air will end up hitting your lenses.”

If you’ve crafted your own cloth mask, create a seal around the nose by inserting a moldable item into the upper part of the mask, Slusky says. This could be a paper clip, pipe cleaner, twist tie or folded piece of aluminum foil.

Looking for more advice on how to properly wear your face mask? The CDC details how to make a face mask (and how to clean it afterward).

3. Adjust your glasses

If your glasses have nose pads, you can tweak the pads so that the frames sit slightly farther from your face, Knight says.

“This will allow that hot air to escape instead of getting trapped between your face and the lenses of the glasses,” she says.

Knight cautions that altering the nose pads may slightly change your vision if you wear glasses with progressive lenses or lenses with a strong prescription. If that happens, you might need to hold your head at a different angle to compensate for the vision change, she says.

4. Try de-fogging products

Applying over-the-counter anti-fogging sprays, waxes and gels to your lenses before putting on your glasses can quickly disperse tiny fog droplets when you’re wearing a mask, Knight says.

“Some work better with different body chemistry, so you may need to try a few brands to see which one works best for you,” she says.

She warns against using anti-fogging products designed for cars or other purposes, as they might ruin your prescription lenses.

Ask us about the anti-fog wipes we stock in practice.

5. Breathe downward

Well, it might be awkward, but breathing downward can be a quick ant-fog fix, Slusky says. This sends the air away from your glasses.

How do you breathe downward? Hold your upper lip over your lower lip. Then blow air downward, as if you’re playing a flute.

6. Check out anti-fog lenses

This won’t fix your foggy-lens problem right away, but you might consider buying lenses with an anti-fog coating. (such as Optifog lenses) An anti-fog coating gives you a hassle-free answer to foggy lenses, regardless of whether the obstructed vision is triggered by a face mask or something else.

orignal source:

allaboutvision.com/en-gb/coronavirus/avoid-foggy-glasses-face-mask/

article edited


Eye Twitching: 8 Causes and Treatments

Woman rubbing her eyes to deal with eyelid twitching.

Causes of eye twitching include:

  • Stress
  • Fatigue
  • Eye strain
  • Caffeine
  • Alcohol
  • Dry eyes
  • Nutrition problems
  • Allergies

What is an eye twitch?

An eye twitch (or more accurately an eyelid twitch) is an uncontrollable eyelid spasm. Most eye twitching lasts only a few minutes, but sometimes an eyelid twitch can persist for days or longer.

When your eyelid is twitching, you might think everyone else can see it. But most eye twitches are subtle and are not easily seen by others.

The medical term for eye twitching is myokymia.

How can I stop eye twitching?

To stop your eyelid twitching, figure out what the possible causes might be.

Sometimes, making minor changes to your diet and lifestyle can significantly reduce your risk of eye twitching or help make an eyelid twitch disappear.

Let’s review the causes of eye twitching and the possible solutions:

1. Stress

Stress is probably the most common cause of eye twitching. Yoga, breathing exercises, spending time with friends or pets and getting more down time into your schedule are ways to reduce stress that may be causing your eyelid twitch.

2. Fatigue

Lack of sleep, whether because of stress or some other reason, can trigger eye twitching. Catching up on your sleep and having a consistent sleep schedule can help.

3. Eye strain

Eye strain — particularly digital eye strain from overuse of computers, tablets and smartphones — also is a common cause of eyelid twitching.

Follow the “20-20-20 rule” when using digital devices: Every 20 minutes, look away from your screen and allow your eyes to focus on a distant object (at least 20 feet away) for 20 seconds or longer. This reduces fatigue that may trigger eye twitching.

Also, ask your optician about computer eyeglasses to relieve digital eye strain.

4. Caffeine

Too much caffeine can trigger eye twitching. Try cutting back on coffee, tea and soft drinks (or switch to decaffeinated versions) for a week or two and see if your eye twitching disappears.

5. Alcohol

If you experience eye twitching after drinking beer, wine or liquor, take a break from the booze, since alcohol consumption may cause eyelids to twitch.

6. Dry eyes

Many adults experience dry eyes, especially after age 50. Dry eyes also are very common among people who use computers, take certain medications (especially antihistamines and some antidepressants), wear contact lenses and consume caffeine and/or alcohol.

If you have a twitching eyelid and your eyes feel gritty or dry, consult your eye doctor for an evaluation. Restoring moisture to the surface of your eye may stop the twitching and decrease the risk of twitching in the future.

7. Nutrition problems

Some reports suggest a lack of certain nutritional elements, such as magnesium, can trigger eyelid spasms. Although these reports are not conclusive, this may be another possible cause of eye twitching.

If you are concerned that your diet may not be supplying all the nutrients you need for healthy vision, discuss this with your eye doctor before purchasing over-the-counter nutritional supplements.

8. Allergies

People with eye allergies can have itching, swelling and watery eyes. Rubbing your eyes because of allergy symptoms releases histamine into your eyelid tissues and tear film, which may cause eye twitching.

Sometimes, over-the-counter eye drops formulated to reduce allergy symptoms can be helpful, but antihistamines in these drops can cause dry eyes.

It’s best to consult your eye doctor to make sure you’re doing the right thing for your eyes if you experience allergy symptoms and eye twitching.

Can Botox stop my eye twitching?

In rare cases, some eye twitching just won’t go away, despite identifying possible causes and applying the suggested treatments.

Persistent eyelids twitches can be treated with Botox injections to stop the involuntary muscle contractions in the eyelid that cause the twitching.

When to see an optician

See an optician immediately if you experience persistent eye twitching, sudden changes in appearance or movement of half your face (including your eyelids), or if both eyelids clamp down so tight it’s impossible to open your eyes. These can be signs of a serious condition.

If your eye twitching doesn’t go away, it could signal a serious neurological condition affecting the eyelid — such as blepharospasm or hemifacial spasm.

These relatively rare conditions are more obvious and severe than common eye twitching and should be evaluated immediately by an optician.

Source: allaboutvision.com/conditions/eye-twitching.htm


Glaucoma: Symptoms, treatment and prevention

 

Glaucoma is often called the “silent thief of sight,” because most of its types typically cause no pain and produce no symptoms until noticeable vision loss occurs.

For this reason, glaucoma often progresses undetected until the optic nerve already has been irreversibly damaged.

What is glaucoma?

Glaucoma is a group of related eye disorders that cause damage to the optic nerve that carries information from the eye to the brain.

In most cases, glaucoma is associated with higher-than-normal pressure inside the eye — a condition called ocular hypertension. But it can also occur when intraocular pressure (IOP) is normal. If untreated or uncontrolled, glaucoma first causes peripheral vision loss and eventually can lead to blindness.

Glaucoma is the second-leading cause of blindness worldwide (behind cataracts).

Types of glaucoma

The two major categories of glaucoma are open-angle glaucoma and closed angle glaucoma. The “angle” in both cases refers to the drainage angle inside the eye that controls the outflow of the watery fluid (aqueous) which is continually being produced inside the eye.

If the aqueous can access the drainage angle, the glaucoma is known as open angle glaucoma. If the drainage angle is blocked and the aqueous cannot reach it, the glaucoma is known as closed angle glaucoma.

Glaucoma symptoms

Most types of glaucoma typically cause no pain and produce no symptoms until noticeable vision loss occurs, but with acute angle-closure glaucoma, one experiences sudden symptoms like blurry vision, halos around lights, intense eye pain, nausea and vomiting.

If you have these symptoms, see an optician so steps can be taken to prevent permanent vision loss.

Diagnosis, screening and tests for glaucoma

During routine eye exams, a tonometer is used to measure your intraocular pressure, or IOP. Your eye typically is numbed with eye drops, and a small probe gently rests against your eye’s surface. Other tonometers send a puff of air onto your eye’s surface.

An abnormally high IOP reading indicates a problem with the amount of fluid (aqueous humour) in the eye. Either the eye is producing too much fluid, or it’s not draining properly.

Normally, IOP should be below 21 mmHg (millimeters of mercury) — a unit of measurement based on how much force is exerted within a certain defined area.

If your IOP is higher than 30 mmHg, your risk of vision loss from glaucoma is 40 times greater than someone with intraocular pressure of 15 mmHg or lower. This is why glaucoma treatments such as eye drops are designed to keep IOP low.

Other methods of monitoring glaucoma involve the use of sophisticated imaging technology to create baseline images and measurements of the eye’s optic nerve and internal structures.

Then, at specified intervals, additional images and measurements are taken to make sure no changes have occurred that might indicate progressive glaucoma damage.

Glaucoma treatments

Treatment for glaucoma can involve surgery, laser treatment or medication, depending on the severity. Eye drops with medication aimed at lowering IOP are usually tried first to control glaucoma.

Because glaucoma is often painless, people may become careless about strict use of eye drops that can control eye pressure and help to prevent permanent eye damage.

In fact, not complying to prescribed glaucoma medication program one of the major reasons for blindness caused by glaucoma.

If you find that the eye drops you are using for glaucoma are uncomfortable or inconvenient, never discontinue them without first consulting your optician about a possible alternative therapy.

Exercise may cut glaucoma risk

Can you reduce the glaucoma risk? According to a recent European study, exercise lessens the chance that some people will develop glaucoma because it helps improve blood flow in your body and your eyes.

In addition to regular exercise and an active lifestyle, you also can reduce your risk for glaucoma by not smoking, maintaining a healthy weight, and eating a varied and healthy diet.

Source:

allaboutvision.com/en-gb/conditions/glaucoma/