Visual cues are a pilot’s most-important sensory input. Since good eyesight is essential for safe operation of an aircraft, pilots must demonstrate adequate visual performance at every aeromedical exam. And for many of us as we have aged, we’ve had to squint at the eye chart, and maybe guess beginning with the third line. And the next time around, we were sporting spectacles. In my case, trifocals.

Inevitable changes occur to our eyes as we age, some due to the aviation environment but others because of time. Without proper preventive care and early detection, these changes can result in significant vision deterioration — enough to lose our careers and even our sight.

According to Dr. Stanley Mohler, director of aerospace medicine, Wright State University School of Medicine, “Aging brings gradual changes to the structure of the eye and quality of vision. These changes can result in problems ranging from difficulty focusing on close objects to dry eyes to diseases such as glaucoma and macular degeneration.”

The likelihood of encountering serious eye deterioration in our flying careers is more significant than you might realize. Researchers at Johns Hopkins University’s Bloomberg School of Public Health retrospectively studied visual performance problems of 3,019 regional and air-taxi pilots aged 45-54 contained in aeromedical certification records of the FAA. According to the study, 419 of the 3,019 pilots in the sample developed serious vision problems, the three most-prevalent being corneal problems (16%), glaucoma (15%) and cataracts (7%).

According to the National Eye Institute, glaucoma is a group of diseases that damage the eye’s optic nerve and can result in vision loss and blindness. A major risk factor is too much fluid pressure inside the eye due to blockage of the passages that drain aqueous fluid from the eye. Over time, the pressure can hurt the optic nerve. Most people with glaucoma have no early symptoms or pain from the extra pressure.

When detected in the early stages, glaucoma can be controlled, sometimes simply with eye drops, but treatments can also include pills, lasers or surgery. Without early detection and treatment, however, people with glaucoma will slowly lose their peripheral vision and can eventually go blind. You can protect yourself by having regular eye exams.

If confronted by glaucoma diagnosis, pilots must coordinate with their AMEs, and any initial Special Issuance requires an FAA decision due to the seriousness of the condition.

Cataracts are cloudy areas in the eye’s lens resulting from a change in the protein structure within it. This condition generally occurs after age 50. Symptoms include blurred vision, a loss of color perception acuity, glare, double vision, halos around objects and a need for more light to see clearly. Cataracts often form slowly without any symptoms. Some stay small and don’t change eyesight much. If caught early, cataracts can sometimes be treated with a change in eyeglass prescription. Others may become large or dense and harm vision.

Cataract surgery is relatively simple and actually one of the most-common procedures done in the US. It is performed on an outpatient basis and most who undergo it note a dramatic improvement in their distant vision immediately.

The “good news” for pilots who have cataract surgery is that their ophthalmologist or optometrist can complete the FAA’s Form 8500-7 “Report of Eye Evaluation,” which they can hand to their AMEs. Assuming they meet the visual acuity standards for their class of medical certificate, their respective AMEs can issue a new certificate at the time of the examination.

Retinal disorders, including age-related macular degeneration (AMD), are a leading cause of blindness in the U.S. The macula is the part of the retina that provides sharp central vision. According to the Mayo Clinic, blurred vision and an inability to see clearly the details of objects in the center of the field of vision are the most-common early symptoms of AMD. Other symptoms include distortion of straight lines and changes in color perception.

Over time, AMD can ruin the sharp vision needed to see objects clearly and to do common tasks like flying and reading. Your eye care professional can advise you of other treatment options if you have signs of AMD. Also ask if you should be taking special dietary supplements that may lower your chances of the condition worsening. The National Eye Institute’s research uses a formulation of vitamins C, E and A, zinc and copper to reduce the progression of AMD. Because the symptoms have serious effects on eyesight, macular degeneration treatment requires an FAA decision prior to issuance of a medical certificate.

Other eye problems associated with aging include ”floaters,” so called because they appear as tiny specks or “cobwebs” that seem to float across your eyes, either all at once or over time. You might notice them in well-lit rooms or outdoors on a bright day. Floaters can be a normal part of aging. However, sometimes they are a sign of a more-serious eye problem such as retinal detachment, wherein the retina actually separates from the back of the eye. If you see many new floaters and/or flashes of light, visit your eye doctor right away. This is considered a medical emergency.

Also see an eye care professional if you have eye pain, fluid coming from the eye, double vision, redness, or swelling of your eye or eyelid. Eyelid problems can come from different diseases or conditions. Common eyelid problems include red and swollen eyelids, itching, tearing, being sensitive to light and crusting of eyelashes during sleep. This condition is called blepharitis and may be treated with warm compresses. Other less-common eyelid problems, such as swelling or growths, can be treated with medicine or surgery.

If your eye care practitioner recommends any non-emergency procedures, check with your AME to see if a mandatory wait period is required after the procedure and what type of documentation the FAA will need to reissue a medical certificate. The AME should also know whether the latest administrative rulings from the FAA will allow the AME to issue your medical certificate or if the matter must be considered by the FAA’s aeromedical reviewers.

There are many less-serious eye ailments that can affect your vision and thus your safety and performance in the cockpit. Aging can be accompanied by changes in the quality and quantity of the tears that lubricate the eyes. Tearing (or having too many tears) can come from being sensitive to bright light, wind, extreme temperatures or temperature changes.

Conversely, eyes that itch or burn are an indication of dry eye syndrome, and if left untreated, the cornea may be subject to infections and eventually become scarred. Protecting your eyes, by wearing sunglasses for example, may solve the problem. Your eye care professional may tell you to use a home humidifier, or special eye drops (artificial tears) or ointments to treat dry eye. In serious cases, special contact lenses or surgery may help. Sometimes the cause is an eye infection or a blocked tear duct, which will require the attention of an ophthalmologist.

It takes a finite amount of time for the eyes to refocus their focal length from inside the cockpit to outside the cockpit. This process is called “accommodation.” A young person will typically require about 1 sec. to accommodate, however the speed and degree of refocusing decreases with age. Of further concern is the increased time required for accommodation as a pilot becomes fatigued.

Slow accommodation is of particular concern during takeoff and landing. When on approach, the pilot’s view shifts quickly and often from outside the aircraft to the instruments within. An older pilot’s eyes will take a much longer period of time to refocus than young eyes.

Another area of operations where slowed refocusing matters is when scanning for potential airborne conflict. With a warning from the TCAS, it’s natural to look at the corresponding piece of airspace outside the aircraft, and sometimes back inside quickly to reconfirm the visual information on the screen. Those of us on the “mature side” of the age spectrum will be unable to do this quickly.

The average person has a visual field of about 190 deg., although it’s typically greater for women than men. The field of vision begins to contract after age 35, and in males, this reduction accelerates markedly after 55 years of age. A number of conditions such as vibration, fatigue, hypoxia or, more than likely, cockpit workload can cause the effective field to contract even more.

Another common ailment in older pilots is a diminished supply of blood to the peripheral retina, resulting in impairment of visual function during darkness, especially above 5,000 ft., and increased difficulty locating other aircraft during daylight.

Ironically, changes in your vision can be an early warning sign of the onset of diabetes. Dr. William Davis, a cardiologist and author of the book Wheat Belly, has studied the connection between high blood sugar and a variety of adverse effects on the body. He notes the relationship between blood glucose and cataracts is well defined.

The book states, “Any food that increases blood sugar has the potential to glycate the crystallins of the lenses of your eyes. At some point, injury to the lens exceeds its limited capacity for defect resorption and crystalline renewal. That’s when the car in front of you is lost in a blurry haze, unimproved by putting on your glasses or squinting.”

Persons with high blood glucose levels have a five-fold increase for risk of cataracts. High blood sugar also can cause damage to the retina (retinopathy) as well as the lacrimal glands (dry eyes).

Protect your eyes when away from the airport. Use safety glasses when you mow the lawn, trim the weeds or use motorized hand tools. A shard of metal could blind your eye in an instant. Wearing a hat with a wide brim when outside will also protect your eyes from too much sunlight.

The American Optometric Society recommends regular vision checkups every two years or more often by an ophthalmologist or optometrist. Update your glasses and contacts prescription at least every two years, or more often if you notice problems. Discuss current health issues with your eye doctor. Being on the alert for certain signs and symptoms can lead to early detection and treatment.

According to the American Academy of Ophthalmology, family history, age, gender and race may also determine how prone you are to certain eye diseases. As with many other health concerns, minority populations are at a greater risk for eye disease and vision loss. The leading causes of blindness for African-Americans are glaucoma and cataracts. African-Americans are also at greater risk for diabetic retinopathy. Glaucoma is the leading cause of blindness among Hispanics. Asian-Americans have a higher risk for glaucoma and diabetic retinopathy.

Regular physical exams are needed to check for diseases like diabetes and high blood pressure since these can cause serious eye problems if left untreated. Headaches can be a sign of vision problems and should be evaluated by a physician if they become chronic. A sudden, painful headache can be a sign of something worse than eyestrain and should be taken seriously and checked out immediately.

Overuse of computers and video games, and reading in dull light can all cause eyestrain. Be sure to take frequent breaks from these activities and use sufficient lighting in order to read properly.

If your mother insisted that eating carrots helps improve vision, she was right. Eating foods that contain carotene, like carrots, can improve your nighttime vision. Research suggests that eating a well-balanced diet that includes plenty of fruits and vegetables may help to prevent some age-related eye diseases while diets high in saturated fats and sugar may increase the risk. Proper amounts of vitamins, especially those containing antioxidants, and minerals, are necessary as well to fill any dietary deficits. And, yes, regular exercise and adequate rest are important to good eye health.

The Johns Hopkins study quite logically concluded that identifying and preventing vision problems among pilots is an important component of aviation safety. As we age, our vision becomes more vulnerable, so take good care of your eyes. Doing so will not only help safeguard your eyesight and career, but also your quality of life. (PS: Carrots, anyone?) B&CA