Faulty eye vision due to clouding of clear lens of the eye is termed as cataract. It can affect one or both eyes. The person feels as if viewing through a fogged glass. Cataract symptoms develop gradually due to changes in tissue of the eye lens either due to aging or injury. Due to aging tissue of the eye lens break down and form small clumps that in turn cause clouding of the lens. As the breakdown continues more of the lens becomes cloudy. The clouded lens scatters the light preventing formation of clear sharp images on the retina. Hence, vision gets impaired. Risk of cataract is high in individuals with diabetes, high blood pressure, obesity, had a history of eye injury or inflammation and family history of cataract. Smoking, increased intake of alcohol, increased exposure to sun light, exposure x-rays and radiation therapy used to treat cancer also increase the risk for cataract.
Depending on the portion of the lens being attacked initially, cataract is categorized in to three types. Nuclear cataract affecting the central portion of the lens causes difficulty in recognizing colors, Cortical cataract affecting the edges of the lens causes problems with glare and posterior subcapsular cataract that develops faster compared to other types starts at the back of the lens and affects vision in bright light, reading vision and night vision. Cataract that develops by birth is termed as congenital cataract. It develops when the mother catches with an infection during pregnancy or due to certain inherited disorders such as galactosemia. Majority of congenital cataracts do not affect vision. If the cataract is found to affect the child’s vision then it is eliminated by surgery.
Symptoms of Cataract
Initial symptoms may not be noticeable and even the eyes look normal. As the cataract grows in size and starts to cover greater part of lens then the patient may experience cataract symptoms. The pupil also starts to appear white or grey in color.
Commonly observed cataract symptoms include:
- Difficulty to see at nights.
- Blurred or dim vision.
- Sensitivity to light.
- Experiencing halos around the light.
- Frequent change in prescription lens.
- Double vision.
- Colors start to appear dull.
- Problems with glare in broad daylight.
It is very important to consult ophthalmologist if you experience change in vision such as blurred vision, double vision or sensitivity to light. Change in eye vision due to cataract does not cause any pain. If pain or redness of the eye accompanies change in vision then immediate medical attention should be taken to prevent loss of sight as it could be due to infection or injury.
Treatment of Cataract
If decreased vision is due to cataract alone then vision can be regained through simple cataract surgery. However, vision cannot be improved if cataract is associated with other diseases such as glaucoma, damage of optic nerve due to glaucoma, diabetic retinopathy and macular degeneration. As damage caused by these diseases is generally irreversible.
Tests such as visual activity test, slit lamp examination and retinal examination are performed to detect the presence of cataract and associated diseases.
Initial cataract symptoms can be managed by changing the lenses of the eyeglasses, using sunglasses to avoid glare and by reading in bright light. If the cataract is mild Phenylephrine and homatropine eye drops are used to improve vision. In diabetics progress of cataract is controlled by using aldose reductase inhibitors.
If cataract impairs vision completely then cataract surgery is mandatory to improve vision. It should be remembered that postponing cataract surgery will not affect your chances of regaining vision after surgery as cataract does not damage eye.
Cataract surgery involves removal of cloudy layer of lens and replacement of the same by plastic lens implant to correct the eye vision. Intraocular lens used for implantation in the eye include monofocal lens, Toric lens or multifocal lens. Of all the three varieties of lenses monofocal lens are used widely.
Surgical procedure varies depending on the extent of the growth of the cataract.
- Phacoemulsification: This is the simplest form of cataract surgery that can be performed in less than thirty minutes with minimum sedation. Due to very minimal invasion the wound is not closed with stitches and it is also not essential to use eye patch after surgery.
- Extracapsular cataract surgery: This procedure is used to remove cloudy lens that is too dense to dissolve by phacoemulsifciation. Cataract is removed as one piece by making a large incision and the wound is closed with stitches after placing the artificial lens. Visual recovery takes time and an eye patch should be used after surgery.
- Intracapsular surgery: In this method the cataract along with the capsule is removed by making an even larger incision than in extracapsular surgery. In this procedure lens implant is placed at a different location. Intracapsular surgery is used in case of severe trauma.
- If it is not possible to implant lens during cataract surgery then vision is corrected after surgery using either contact lens or eyeglasses. Surgery is performed to only one eye at a time. If both eyes are to be operated then there should be few weeks gap between surgeries. Except for the risk of bleeding and infection cataract surgery is safe.
Simple measures to postpone cataract surgery
Practice of simple measures after you start to experience cataract symptoms can help to postpone the cataract surgery for a while.
- Use of eyeglasses with accurate prescription lenses.
- Use of sun glasses to avoid exposing to powerful ultraviolet rays of sunlight.
- Limit or avoid night driving.
- Use of magnifying glass for reading.
- Use of bright lamps at home to improve lighting.
Once cataract has grown enough to interfere with your daily activities consider undergoing cataract surgery.
Cataract : Prevention and precautions to be taken
It is not possible to prevent development of cataract with age. However, the risk for cataract can be reduced by taking few precautions.
- Taking well balanced diet rich in fresh fruits and vegetables. In addition to offering the required vitamins and minerals, antioxidants present in fruits and vegetables prevent damage to eye lens.
- Using sun glasses to prevent exposure of eyes to powerful ultraviolet rays of sunlight.
- As obesity is one risk factor for cataract it is recommended to maintain optimum weight by regulating diet and practice of physical activity.
- Keeping diseases such as diabetes and high blood pressure under control by taking required medications.
- Taking steps to quit smoking.