You might be surprised at how many tests eye doctors use to diagnose glaucoma. A proper diagnosis requires careful evaluation of many aspects of your eye’s health – from eye pressure to cornea thickness to the health of your optic nerve. This article describes how your eye doctor assesses your risk and all the tests needed to properly diagnose glaucoma.
Your eye doctor will begin by assessing your risk level for developing glaucoma. This will help determine the frequency and extent of testing needed. Through a family history and medical questionnaire, the eye doctor is looking for the following risk factors:
Over the age of 60
Ethnic background such as African or black Caribbean descent, Hispanic, or Asian
Family history of glaucoma, such as a sibling or parent with glaucoma
History of eye conditions, injuries or surgeries
Prolonged corticosteroid use (eye drops, pills, inhalers or creams)
Chronic conditions that affect blood flow, such as migraines, diabetes, low blood
pressure or hypertension
Current or former smoker
If you’ve already had a comprehensive eye exam, your eye doctor will also consider these risk factors:
Eye pressure higher than normal (above 21 mm Hg)
Thin corneas (less than 0.5 millimeters)
Your type of eyesight is also important. People with farsightedness are at a higher risk for narrow-angle glaucoma, a more serious type that can advance quickly. While nearsightedness is associated with open-angle glaucoma, which progresses slowly without any symptoms.
During a comprehensive eye exam, your eye doctor will always check for glaucoma, regardless of the risk level. This provides a baseline for comparison as you age. There are two tests: tonometry and ophthalmoscopy.
Tonometry measures the pressure within your eye. Your eye doctor will give you drops to numb your eyes. Then he/she will use a device called a tonometer, which applies a small amount of pressure with a warm puff of air.
Eye pressure is unique to each person, so it’s not always a reliable indicator for glaucoma. It’s simply another piece of information to help your eye doctor assess your eyes. The range for normal pressure is 12-22 mm Hg (“mm Hg” in millimeters of mercury, a scale for recording eye pressure). Most glaucoma cases are diagnosed with pressure over 20mm Hg. However, some people can have glaucoma at pressures between 12 -22mm Hg.
This is an examination of your optic nerve. Your eye doctor will use eye drops to dilate the pupil, which makes it possible to see through your eye to examine the shape and color of the optic nerve. Then, using a small device with a light on the end, your optic nerve is magnified. Based on the results of these tests, your doctor may ask you to have more glaucoma exams.
Perimetry is a visual field test. It creates a map of your complete field of vision. During this test, you’ll look straight ahead and then indicate when a moving light passes your peripheral (or side) vision. Try to relax and respond as accurately as possible. To ensure accuracy, your doctor may repeat the test to see if the results are the same the next time. If you’ve been diagnosed with glaucoma, a visual field test is usually recommended at least once per year to assess changes to your vision.
This diagnostic exam helps determine the angle of your iris and cornea. First, you’ll receive eye drops to numb the eye. A hand-held contact lens is gently placed on the eye. A mirror on the contact lens shows the doctor if the angle is closed and blocked (a possible sign of angle-closure or acute glaucoma) or wide and open (a possible sign of open-angle, chronic glaucoma).
Last, your eye doctor may want to use pachymetry as another way to confirm a diagnosis. Pachymetry measures the thickness of your cornea, the clear window at the front of the eye. A probe called a pachymeter is gently placed on your cornea to measure its thickness. Pachymetry can help clarify your diagnosis because corneal thickness has the potential to influence eye pressure readings.
Glaucoma diagnosis is not as simple as you might expect. Be sure to have regular eye exams, especially if you have any of the risk factors, to detect glaucoma early.
If you’ve been diagnosed with cataracts, you may wonder if cataract surgery is right around the corner. Not to worry. There are many preventive steps you can take to slow the progression of cataracts and preserve your vision. That doesn’t mean you won’t eventually need surgery, but you can at least delay the need for quite a while.
The National Eye Institute recommends protecting your eyes from the sun's harmful ultraviolet (UV) and high-energy visible (HEV) rays by always wearing good quality sunglasses while outdoors. Look for sunglasses that block 100 percent of UV rays and absorb most HEV rays with large lenses or a close-fitting wraparound style. Remember that the peak hours for sun exposure are between 10 am and 3 pm or 11 am and 4 pm during daylight savings time and that the sun’s rays are strong enough to pass through clouds, so you need your sunglasses every day.
Steroid eye drops are routinely prescribed to treat dry eyes or an arthritic flare-up in the eyes. Unfortunately, they can also speed up the progression of cataracts. Talk to your Optometrist about how you can manage both conditions without inadvertently making your cataracts worse – and hastening the need for surgery.
There are over 300 commonly prescribed medications with side effects that may impact cataract progression. Since your primary care physician may not have access to your eye doctor’s medical records, be sure to ask your doctor if your current medications will affect your cataracts. If you must stay on the medication, it’s even more important to avoid sunlight during peak hours and to wear sunglasses.
If you haven’t quit already, here’s another good reason to do it: over time, the damage from smoking can double or triple an individual's risk of developing cataracts. If you’ve been a smoker, your habit was probably a big contributor to the diagnosis. The good news is – by quitting smoking now, you can slow the progression of cataracts.
Studies have shown that certain vitamins and nutrients may reduce age-related decline in eye health, particularly antioxidants. If you’ve already been diagnosed with cataracts, adding foods rich in antioxidants to your diet will help slow the progression. This list isn’t exhaustive, but here are some examples to get you started: dark chocolate, blueberries, strawberries, pecans, carrots, sweet potatoes, artichokes, kale, red cabbage, beans, beets, spinach, apples, and plums.
Doctors also recommend eating more fish high in omega-3 fatty acids. This has been linked to a potentially reduced risk of cataracts or their progression. You may also consider taking a multivitamin that contains Vitamin C and E. Talk to your doctor or nutritionist about how you might adopt a healthy eating plan that’s designed to prevent cataracts.
Fortunately, making these healthy modifications to your diet can prevent many other lifestyle diseases such as diabetes. Studies have shown that a diet rich in processed carbohydrates can increase your risk of both developing cataracts and speeding up its progression. It’s important to develop a plan that works for you and supports your holistic health.
Take control of your cataract diagnosis by getting regular eye exams, communicating with your doctor, and putting these tips into practice. You’ll have better vision and prevent the need for cataract surgery in the near future.