September 21, 2020

Your Aging Vision

by Dr. Jane Thrall

As with most things, age changes the way we see the world.

Eyes and the visual system are complicated and sensitive. Visual health is affected by many life choices, including what we eat, how much exercise we get, and any bad habits picked up along the way.

The most common eye conditions in older people are cataracts, glaucoma, and age‑related macular degeneration (ARMD).

Cataracts

Cataracts are a clouding of the lens inside the eye, a very common condition in patients over sixty years of age. When the lens clouds, vision becomes distorted and dull. The process is usually so slow that it is barely noticed until road signs are difficult to read and night driving becomes unnerving.

Cataract surgery is simple and highly successful with minimal risk. The most common thing I would hear after a patient had their first eye done was, “When can I get the other one done?”

During a procedure called phakoemulsification, the surgeon makes a small incision in the eye and inserts a device that breaks up the lens and removes it in tiny pieces. An intraocular lens of the appropriate strength is inserted to replace the natural lens, and sight is restored. New glasses are prescribed if needed, but often patients only require reading glasses.

Glaucoma

Glaucoma is an eye condition that has few or no symptoms; patients invariably present with no concerns unless they’ve lost nearly all their sight.

Historically it was thought that glaucoma was a condition of high pressure in the eye. While there is a strong association between eye pressure (intraocular pressure or IOP) and glaucoma, it turns out that’s not the whole story.

Fluid is always flowing into and out of the eye. This aqueous fluid keeps the eye healthy and free from disease. When something goes awry with this process, pressure within the eye builds up. This increased pressure compresses tissue and affects the flow of oxygen and important nutrients to the optic nerve tissue, which conveys sight to the brain. The nerves affected first are the ones associated with peripheral vision, and the last to go are the central nerves from the macula.

Peripheral vision is lost one cell at a time, but the pattern, in most cases, is predictable. Special screening tests have been developed to flag those who may be experiencing early changes to their peripheral vision and more in-depth tests can monitor the vision changes.

The trouble comes when a patient doesn’t seem to have particularly high IOP and aren’t flagged for further testing. Some people have a below-average pressure reading and still experience changes associated with glaucoma, a phenomenon still not fully understood.

Monitoring a person’s IOP over time, and regular screening of peripheral vision, may detect a problem otherwise missed.

In most cases, glaucoma is treated with either eye drops or surgery. It may depend on whether the problem is excessive fluid production, poor drainage, or a combination. Eye drops have come a long way in the past half century, and newer drugs are more efficient with fewer side effects.

Age-Related Macular Degeneration (ARMD)

A common eye condition in the elderly, macular degeneration, causes distortion in the retina and can damage the tissue enough that complete areas of sight disappear. Unlike glaucoma, ARMD affects central vision and can make reading difficult. Straight lines may appear crooked, or the horizon may look wavy. Left untreated, ARMD will cause blindness and loss of mobility.

ARMD is strongly associated with other health conditions including hypertension, high cholesterol, and lifestyle choices such as smoking and high fat intake. Genetics plays a role, and Caucasians are more likely to develop the condition.

In the past few years, several successful treatment options to slow the progress of ARMD have evolved. Vascular endothelial growth factor inhibitors are being injected directly into the eye to slow disease progress with good success.

Healthy Habits

The best option is still prevention through lifestyle modification. I once had a patient make a scene and leave my office because I suggested that his failing vision was in part related to his two-pack-a-day smoking habit. While genetics plays a huge part in our aging health, so do many outside factors such as diet, exercise, and yes — smoking. When we first notice changes, it’s not too late to make adjustments to improve our health and sight.

It’s important to get regular eye health assessments because all conditions can be better treated if caught earlier in the process.


Jane Thrall, OD, is a retired optometrist with over twenty‑seven years in practice and a special interest in laser refractive surgery. She’s now dedicating her retirement to golfing, gardening, writing, and reflecting.