eyediology - opticians - london

Cataract Screening


A cataract is an opaque film or cloudiness that occurs in the lens within the eye. It may consist of varying size opacities and/or water vacuoles. In general, it is an alteration in the normal lens tissue that reduces its normal high degree of transparency. This, in turn, interferes with the degree and quality of light reaching the retina.


A patient with a cataract may experience any of the following symptoms: blurred vision, poor night vision, sensitivity to sunlight and halos around lights.

Risk Factors

Risk factors include radiation (sunlight and treatments), smoking, alcohol, medications, and genetics. The main cause of cataracts is sunlight radiation. The sunlight tans the lens inside our eye much like it tans our skin. Whereas we get new skin cells on an average of every 26 days, the lenses inside our eyes have to last our entire lives. The energy in the sunlight, particularly ultraviolet radiation, causes the formation of unstable molecules called free radicals. These free radicals change the lens tissue, causing distortion and darkening. Cataracts can be directly or indirectly affected by medications and diseases. Many medications cause the pupil to dilate, allowing more harmful light into the eye. Examples are antidepressants, antihistamines, amphetamines, nitroglycerin, and beta-blockers. Other drugs, such as steroids and tamoxifen, can cause cataracts. Some drugs, like diuretics (commonly called water tablets), cause the tissue to be photosensitized, which results in increased sensitivity to sunlight. Medical conditions such as diabetes, hypertension, rheumatoid arthritis, and other connective diseases are commonly associated with cataracts.


Treatment includes glasses, contact lenses, and surgery. New technologies in eyeglasses and contact lenses allow better vision. Ultraviolet radiation filters, non-glare technology, and the correction of higher-order aberrations with wave front technology can result in better vision through cataract changes. A preventive treatment for the progression of cataracts is polarized sunglasses with the addition of an anti-reflection coating on the backs of the lenses. Cataracts are generally not surgically removed until vision cannot be improved to reasonable levels with eyeglasses or contact lenses. The decision for having surgery usually depends on whether you can see well enough to do what you want to do. An artificial lens is implanted that may provide excellent vision without the need for strong glasses or contact lenses. The prognosis for good vision is excellent. Cataracts tend to progress at a slow pace and, as a rule, can be monitored on a yearly basis. At the appropriate time we can recommend the best surgeon for your particular type of cataract. For the near future, we should monitor your eye health status and cataract development on a regular basis.

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