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