A cataract is a clouding of the normally clear lens of the eye. The lens is what focuses light from the outside world onto your retina. If the lens is cloudy, hazy, yellow or opacified, the image formed on the retina is not sharp or clear and the result is blurred vision.
Cataracts usually develop as part of the normal aging process of the eye; the center of the lens becomes thicker and yellow as a person ages. However, cataracts can form at an earlier age from factors that include certain medical problems (such as diabetes); injuries to the eye; medications (such as steroids); previous eye surgery; long-term, unprotected exposure to sunlight and other unknown genetic factors. A cataract can develop in any part of the lens. It can make the lens thicker, irregularly shaped, denser, yellow or brown, or even shift the lens to a slightly different position within the eye. Cataracts may also develop rapidly, seemingly over a few weeks to months, or slowly progress over years with only minimal visual changes. But whatever the type or severity, cataracts all have one thing in common: a decrease in clear vision.
Symptoms of Cataracts
As there are many different types of cataracts that exist, there are equally as many different symptoms. Common symptoms include: glare or light sensitivity, needing brighter light to read, difficulty with night driving, double vision in one eye, fading or dimming of colors and/or frequent change in eyeglass prescription.
Detection of Cataracts
Although the symptoms of cataracts may be common, the only way to determine if a cataract is present is through a complete examination by an eye care professional at TVLC. There are many possible reasons for blurred or decreased vision. It is important to determine the cause and extent of vision loss before deciding on appropriate treatment.
Treatment of Cataracts
The only real treatment for a cataract is surgical removal. Contrary to popular belief, cataracts are not removed by laser. Most cataract surgery today is done by ultrasound disruption of the lens, called phacoemulsification, with placement of a clear acrylic or silicone lens implant. Once a cataract is removed, it cannot "grow back." Cataract surgery is the most common and most successful surgery in America. Roughly 1.4 million cataract surgeries are performed each year, with a greater than 95 percent success rate. However, as with any surgery, there are risks, and these will be discussed in detail with your TVLC provider before planning cataract surgery.
Glaucoma is an eye disease in which the optic nerve - the part of the eye that carries the images we see to the brain - is damaged. The optic nerve contains many small nerve fibers that are very sensitive to pressure changes inside the eye. If the intra-ocular pressure (pressure inside the eye) exceeds a critical level (which may be different for each person), damage to the optic nerve begins. Once destroyed, these nerve fibers cannot regenerate. This can lead to permanent vision deficits such as blind spots, visual field defects or even complete blindness. Early detection and control of intra-ocular pressure are the keys to preventing optic nerve damage and blindness from glaucoma.
Causes of Glaucoma
There is a fluid produced by a part of the iris called the ciliary body that fills the front portion of the eye (the anterior chamber). This fluid is known as the aqueous humor. Aqueous humor is produced at a constant rate by the ciliary body, where it circulates through the anterior chamber then flows out of the eye at the same rate through the drainage angle (area between the iris and cornea). This steady state of aqueous humor flow keeps the pressure in the eye relatively constant. If, however, the rate of flow out of the eye decreases (from blockage of the drainage angle), the continual influx of aqueous humor will cause the pressure inside the eye to increase potentially, causing damage to the optic nerve.
Types of Glaucoma
The type of glaucoma is related to the way in which the drainage angle is blocked. Chronic open-angle glaucoma, the most common form, arises when the drainage angle becomes inefficient at allowing fluid flow from the eye. The pressure gradually increases over time, and damage to the optic nerve is slow and progressive. The damage is so slow and painless that there are no noticeable symptoms until the optic nerve is significantly damaged. The risk of open-angle glaucoma increases with age, and treatment is aimed at lowering the intra-ocular pressure through eye drops, laser or surgery.
The other type of glaucoma, angle closure glaucoma, occurs when the drainage angle is completely blocked by the iris. This can cause a sudden increase in intra-ocular pressure leading to blurred vision, severe eye pain, headache, nausea or vomiting and halos (colored) around lights. This is known as an acute angle-closure and represents a true eye emergency. Blindness from this type of glaucoma can occur rapidly, sometimes within hours if not treated. Angle-closure glaucoma is seen more often in people with smaller (farsighted) eyes and those of Caucasian heritage, but is relatively uncommon with respect to chronic open angle glaucoma. Treatment usually involves laser surgery and eye drops.
Risk of Glaucoma
Although there are many factors that contribute to the risk or likelihood of developing glaucoma, the three with the most significance include, age, family history and past eye injuries. But everyone, despite presence or absence of risk factors, should be screened for glaucoma regularly.
Detection of Glaucoma
The best way to detect glaucoma is with regular eye examinations by an ophthalmologist. Complete evaluation should include dilated examination of the retina (ophthalmoscopy), inspection of the drainage angle (gonioscopy), measurement of intra-ocular pressure (tonometry), measurement of the corneal thickness (pachymetry) and testing of the peripheral visual field of each eye (perimetry). All are necessary to detect and treat glaucoma.
Treatment of Glaucoma
Treatment depends on the type and severity of the glaucoma and may include eye drops, laser or surgery. All are aimed at lowering the pressure and preserving optic nerve function and vision.