Cataract Diagnosis

An accurate cataract diagnosis is the first step toward clearer vision. Because cataract surgery is a safe and effective procedure performed on approximately 3 million Americans each year, patients can rest assured that proper treatment will enable them to once again see clearly.

In many cases, a routine eye exam will reveal the presence of cataracts even before the patient experiences any symptoms. In other instances, the worsening symptoms of cataracts cause the patient to seek professional help. In either case, the diagnostic process is the same, and is performed by a qualified ophthalmologist.

The Importance of Regularly Scheduled Eye Exams

In order to maintain healthy eyes, the American Optometric Association (AOA) recommends that adults aged 18 to 60 have an eye exam once every two years, while patients 61 and older should attend appointments annually. Because cataracts begin to form long before symptoms manifest themselves, regular eye exams can diagnose-and treat-cataracts early, minimizing the loss of visual acuity.

When to Seek Help

In advanced stages, cataracts interfere with the passage of light to the retina, resulting in significant changes in your vision. If you are not attending regularly scheduled eye exams, it is important to seek medical advice if any of the following cataract symptoms develop:

• Blurred eyesight
  
• Poor night vision
• Sensitivity to light and glare
  
• Frequent changes in your glasses or contact lens prescription
  

Because these symptoms may indicate cataracts or another eye disease, it is important to have any visual distortion evaluated by a medical professional.

How Cataracts Are Diagnosed

To achieve an accurate cataract diagnosis, your ophthalmologist will use a series of tests to evaluate the health of your eyes and the quality of your vision. Many of these tests are performed as part of a routine eye exam.

Slit Lamp Exams

To examine the health of your eyes, your ophthalmologist will first dilate your pupils with eye drops. Then, using an instrument known as an ophthalmoscope, he or she will project a high intensity light beam on the front parts of the eye, including the cornea, lens and iris. The close examination allows your ophthalmologist to see any protein build-up on the lenses, which is what causes cataracts. This direct physical examination of the eye can reveal lens opacity even before cataracts begin to affect your vision, achieving the earliest possible cataract diagnosis.

Because it is important to examine the eye for additional or alternative diseases that may be compromising vision, your ophthalmologist will also place a special lens between the slit lamp and the cornea in order to magnify the retina and optic nerve. Damage to the optic nerve may indicate increased intraocular pressure (IOP), which can indicate cataracts or glaucoma.

Eye Charts

To determine whether the cataracts forming on your lens are affecting your vision, your ophthalmologist will test your eyesight using a Snellen eye chart. By asking you to read letters of varying sizes from a chart 20 feet away, your doctor can determine your visual acuity and track any vision loss resulting from your cataracts. If you have received a cataract diagnosis, and your visual acuity has decreased to the degree of 20/40, your ophthalmologist will likely recommend cataract surgery.

During a Snellen eye test, patients are asked to read black letters off of a white background, which creates a high level of contrast that differs significantly from real-world conditions. In fact, patients may score highly on a Snellen eye test, but still complain that they are experiencing extremely blurry vision, difficulty driving at night, and other frustrating symptoms. In order to get a more realistic view of how patients' eyes are performing on a daily basis, your ophthalmologist may present you with additional eye charts designed to measure color perception, contrast sensitivity, and reaction to glare.

• Ishihara Color Test: Patients read colored numbers off of a similarly pigmented background in order to determine their contrast sensitivity. Because advanced cataracts may diminish your ability to see colors on the "blue" end of the spectrum, poor performance on an Ishihara color test may indicate that it is time to consider surgery.

• Contrast Sensitivity Test: By asking a patient to identify low contrast letters or sine-wave gratings, ophthalmologists can determine how dramatically cataracts are affecting the patient's quality of vision. In certain cases, contrast sensitivity can be dramatically affected by cataracts even when a Snellen test indicates that visual acuity remains normal.

• Glare Sensitivity Test: Because cataracts can cause light sensitivity, patients are asked to read the same chart twice, once in bright light, to determine eye function under varying light situations. Decreased acuity in the presence of bright light may be indicative of posterior subcapsular cataracts.

Tonometry Tests

Also known as a "puff test," a tonometry test measures the fluid pressure inside the eyes. Using a blunt instrument or, more commonly, a puff of air directed at the pupil, an ophthalmologist is able to determine a patient's intraocular pressure (IOP). An elevated IOP may indicate the presence of cataracts or glaucoma, and over time may cause damage to the optic nerve. For this reason, patients with high intraocular pressure must be monitored with frequent eye exams whether or not they receive a cataract diagnosis.

Monitoring Cataract Progression

Once you have received a cataract diagnosis, your ophthalmologist will track your cataract progression with a series of eye exams. Once your visual acuity begins to diminish, your ophthalmologist will likely recommend cataract surgery. However, your daily experiences are just as important as any diagnostic test. Only you are aware how drastically cataracts are affecting your vision, and only you can determine the best time to pursue treatment.

Contact an Ophthalmologist for an Accurate Cataract Diagnosis

If you are experiencing blurry vision, cataracts may be to blame. To receive an accurate cataract diagnosis, contact an experienced ophthalmologist in your area today

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