Pesky Presbyopia

DO you often hold printed pages like this one at arm's length in order to read them clearly? Or do you routinely slip on a pair of non-prescription reading glasses, the sort you can pick up off a pharmacy rack, so you can read your Sunday morning papers?

Either way, if you are over 45, such habits most likely mean you are subject to a pesky aspect of ageing called presbyopia.

Oh My, Another -opia?

You might be familiar with the terms myopia (short-sightedness), and hyperopia (long-sightedness), but not presbyopia.

Short-sightedness is a condition where you have clear vision when viewing something close up, but blurry vision when viewing something far away. Long-sightedness is the opposite - clear vision when viewing things far away, blurry vision close up.

Presbyopia, on the other hand, is a condition where your 'near vision' i.e. your clear vision when viewing something close up gradually declines. Left alone, it can make near tasks like reading fine print or sewing difficult or impossible.

While near- and far-sightedness are caused by physical imperfections in the eye that are usually inherited (too much or too little curvature in the cornea, eyeballs that are too long or short), presbyopia develops as the lens of the eye ages and hardens.

In a normal eye, the cornea and lens focus light precisely onto the retina (the innermost, light-sensitive layer of the eye.) To do this, the lens needs to be flexible - when you look at something nearby, a ring of muscles around the lens contracts and your lens fattens, bringing the near object into focus; when you look at something far away, the muscle ring relaxes and your lens flattens, bringing the far object into focus.

The retina then sends coded signals to the brain, via the optic nerve, for interpretation. It is as if the retina asks the brain 'What am I reading?' and the brain answers 'Oh my, another -opia,' faster than you can blink.

In a presbyopic eye, the retina asks the same question, but the brain sees a blur because the lens can no longer bring the words into focus. So the presbyopic person compensates by moving the page further away from him (to the closest point he can focus on) or magnifying the image with visual aids like reading glasses or a magnifying glass.

Correcting presbyopia is a simple matter of seeing an optometrist and finding a pair of spectacles or contact lenses that works for you. Uncorrected presbyopia can lead to unecessary eyestrain or headaches after doing close work and the loss of near vision. Unfortunately, uncorrected presbyopia is all too common.

One Person in Six Has Presbyopia

A recent study on the prevalence of uncorrected presbyopia around the world, published in the Archives of Ophthalmology estimated 1.04 billion people suffered from the condition as of 2005.

There were a billion presbyopes in 2005, and in 2020 there will be a billion and a half. And that is because the population of the world is aging.

The average age of onset of presbyopia is 45. In temperate countries where UV light exposure is lower, it is later – about 48 in Finland. In countries nearer the equator, like Malaysia, where UV light exposure is higher, it can be as early as 30.

By 65, the condition is almost universal. As people live longer and longer, they can expect to live with the condition for longer and longer too (Malaysia's life expectance is now 74 - 71 for men, 76 for women).

A girl born today in Sydney, Australia has a 50% chance of living to 100. If a woman have lost the ability to read naturally by the age of 45, she have 55 years without the ability to read naturally.

Reading is not the half of it. According to the Global Impairment report, 517 million presbyopes either have no spectacles or have inadequate spectacles to correct their condition. As a result, 4 out of 5 of them are unable to perform necessary near tasks, resulting in lost income for individuals and lost productivity for countries.

Unsurprisingly, the majority of these vision impaired presbyopes come from the developing world where access to adequate eye healthcare is limited or unaffordable, or both. Fortunately, that is not the case here, so do not take those services for granted - take advantage of them instead.

Spectacles and Contact Lenses

An optometrist should say to someone who is presbyopic : 'You can have spectacles - reading glasses or multifocals; you can have one contact lens for near vision, one for distance vision (one monovision lens in each eye); or you can have multifocal contact lenses.

These days, we can get freedom from old-type spectacles; we can get more opportunities to be more active in our lifestyles, and presbyopic contact lenses are part of that revolution.

They are becoming more successful because they are more reproducible, have better oxygen permeability, and are better designed.

Seeing an Optometrist

Failure to see an optometrist regularly for something unthreatening like presbyopia may result in other, more threatening eye problems being missed e.g. glaucoma (leading cause of blindness worldwide), age-related macular degeneration (AMD, leading cause of blindness in elderly Americans), or diabetic retinopathy.

For adults, it is recommended a visit :

* Once every five years, or
* Once every two years if you have a family history of glaucoma, diabetes, hypertension, AMD, or a personal history of eye injury

Additionally :

* Have a 'baseline' check when you turn 40
* Up your frequency to every one to two years after age 60-65

Children should visit an optometrist :

* At least once when they enter primary school
* At least once when they enter secondary school

What Else Can You Do?

You can not prevent presbyopia, but you can hold it off for longer by protecting your eyes and vision :

# Use the right glasses, read in good light.

# Eat fruits, leafy greens, and other antioxidant-rich foods. Antioxidants help slow the oxidative stress of ageing in the eye.

# Say 'no' to UV light. Wear spectacles and contact lenses that have full UVA and UVB blockage (look for the World Council of Optometry seal of acceptance for UV blockers/absorbers.)

· Wear protective eyewear when your eyes are at risk e.g. when playing sports, mowing the lawn, or using toxic substances (look for 'ANSI Z87.1', a US standard of effectiveness in protecting against injury, on the lens or frame.)

More info on PREBYOSPIA here.

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