Understanding Cataracts

Just as fingerprints on a camera lens cause blurred pictures regardless of our efforts to focus, a cloudy lens within the eye causes blurred vision. When the human lens becomes cloudy or hazy enough to interfere with vision, it is called a cataract. Changing glasses will not help the blur that is caused by a cataract.

Just as defective film will spoil photographs, a weak retina or nerve (e.g., conditions such as macular degeneration, epiretinal membrane, or glaucoma) will cause blurred vision in eyes despite a clear lens and proper focus (glasses). Good vision always requires (1) optimal focus – usually with glasses, (2) a clear lens, and (3) a healthy retina and nerve.

Some cataracts are congenital (inborn), but they can also be caused by injuries, diabetes, radiation, or prolonged use of certain medications, such as steroids. Highly nearsighted patients may develop cataracts at a younger age. However, most cataracts result simply from the natural aging process of the human lens. They do not occur at the same age or rate in everyone.

To take the place of the clouded human lens, a tiny, delicately engineered artificial lens is implanted into the eye. The modern intraocular lens “implant” does not change the appearance or sensation of the eye. The implant is permanent. Unlike a contact lens, it cannot fall out. Occasionally, the membrane behind the replacement lens gets cloudy, and a quick laser procedure can be performed to polish it.

The “prescription” or power of each patient’s implant is selected based on computer calculations that use a series of precise eye measurements performed in the office prior to surgery. The distance between the front of the eye and the retina can be measured precisely using optical methods. This painless test is called biometry.

Recently, newer implant designs that can decrease your dependence upon glasses have become very popular. However, they are not appropriate for all individuals, and the additional cost is not covered by insurance.

I routinely perform “small incision surgery” using specialized technology called phacoemulsification. The firm cataract core is fragmented into small particles that can be gently sucked out through a 2.5 mm incision (1/10th of an inch). Modern foldable lens implants can fit through incisions this small, and sutures are usually not required. Physical activities are not significantly restricted after small incision surgery, and the vision stabilizes faster than with the older large incision method.

Cataracts cause visual symptoms only; they do not cause pain, discomfort, tearing, or redness. The visual symptoms can vary. Blurriness, hazy vision, or increased glare from sunlight and headlights may be present. Some cataracts turn yellow, causing fading of color. Reading may take more effort, and you may tire prematurely. Vision progressively worsens over a period of years or sometimes after only a few months.

The decision to have cataracts removed is almost always elective. Because cataracts do not harm other parts of the eye, nothing needs to be done if you are not significantly bothered by symptoms. However, as activities such as driving and reading become increasingly affected by cataracts, surgery becomes a logical option to consider.

With the success of the modern implant, waiting for cataracts to “ripen” is no longer necessary. Because cataracts will not improve and will eventually worsen, there is no advantage in delaying treatment if vision is sufficiently affected and the prognosis of surgery is good. You are never “too old” to have cataract surgery, just as you are never “too old” to enjoy better vision.

Cataract surgery is microsurgery; it utilizes an operating microscope and is performed inside the eye through an incision. One can think of the human lens as having a thin, transparent “wrapper” that holds the lens in the center of the eye. This delicate, cellophane-like skin is called the lens “capsule.” A hole is made in the front of this wrapper, and the cloudy lens is removed in several delicate stages. The implant is usually then inserted into this empty wrapper, occupying the original place of the natural lens.

There is some risk with any surgical procedure. For each patient, I carefully weigh the risk/benefit ratio. Fortunately, in experienced hands, severe complications that could worsen the vision are rare. The chances of eyelid, cornea, retina, and ocular pressure problems may depend on individual circumstances, but all may occur even without surgery – that is, with aging alone. With modern advances in technique, more than 98% of patients with otherwise healthy eyes will gain significant visual improvement following surgery.