What is Cataract?
Normally, the crystalline lens of the eye and its capsule is clear and allows ordered refraction of rays of light to the retina so that we can see everything clearly. Cataract is a state of opacification of this crystalline lens of the eye or its capsule, as shown in the diagram above. Due to this opacification rays of light entering the eye get dispersed in an unorderly fassion causing glare, foggy vision, and reduced visual acuity. The amount of light entering the eye varies with the amount of opacification of the lens or the capsule of the lens. (Image taken from Allergan patient education series)
Why does it occur?
By far the most common form of cataract seen is “age related”, starting somewhere in the late 50’s or 60’s. Theoretically cataract occurs due to either water imbibed into the lens fibres or their coagulation, causing opacification. The former is reversible, the later is not. There are numerous hypotheses as to why such changes occur in the lens. Some of the common causes of lens opacification are listed below.
- As a normal ageing process
- Due to the presence of Diabetes Mellitus
- Due to physical or chemical injury to the eye
- Due to a local disease of the eye (for example iridocyclitis)
- Due to medications instilled in the eye; for example for glaucoma, steroids for iritis, etc.
- Due to exposure to Ultraviolet or Infrared radiations, X-rays, persons exposed to such radiations in their professions develop cataract earlier
- Profound debilitation or illness
- Following sever diarrhoea, dehydration, undernutrition, starving, unsupervised dieting
- Cataract in the eyes of the young are usually due to genetic defects and such syndromes, in which case they may be seen at birth or immediately after birth. The other common cause in children is injury to the eye.
Any of the above insults to the cyrstalline lens of the eye cause disruption in the ordered arrangement of lens fibres within the lens causing opacification (cataract).
Symptoms vary with the amount of lens opacity and the location of the lens opacity. If the opacity is situated in the center of the lens, vision is reduced in bright light due to constriction of the pupils and better in the evening or night due to dilation of the pupils. Similarly with peripheral opacities, vision is better during the day, or in good light, and worse at night or in poor light.
Patients with cataract experience “glare” due to haphazard dispersion of light in the eye due to opaque lens fibres. Some patients also experience “colored haloes” around sources of light at night due to prismatic dispersion of rays by the lens opacitites.
Another early symptom of cataract is “foggy” vision, as if seeing through a fog or a misty glass pane. This is because of opacification of the lens which is not sufficient to grossly reduce the entry of light into the eye, just disperse it.
Advanced cataracts gradually produce reduced vision, inability to make out faces, read, watch television,
Occasionally neglected cataracts can “hypermature” causing an increased pressure within the eyeball (glaucoma), causing pain, loss of vision, redness, and watering from the affected eye. This is a medical emergency and should be attended at once, or eyesight may be permanently lost.
Medical management of Cataract
In most cases of early cataract vision can be improved with spectacles. Apart from standard spectacles a number of low vision aids are also available for people who can not undergo surgery for cataract till a time when absolutely needed. Magnifying lenses can help with routine near work like reading, signing cheques, etc.
In allopathy there is no medicine which can clear lens opacities. In certain cataracts like the diabetic cataract the level of cataract varies with blood sugar levels in early stages, thus adequate control of blood sugar can clear vision.
Homeopathy and Aurveda claim cures for early cataract in the form of topical medications and oral medications.
Surgical management of Cataract
The only “treatment” of estabilished and advanced cataract is surgery for the removal of the opacified lens. Cataract surgery has come a long way in terms of results, rehabilitation, and quality of life after cataract surgery. There are a few techniques available, but the best results are with phacoemulsification and intraocular lens implantation. The technique used depends on the type of cataract and its maturity. Your ophthalmologist is the best person to decide on the technique to be used. The latest in techniques is laser phacoemulsification, this technique is in its early stages.
The basic principle is removal of the subcapsular opaque lens, polishing of the capsule, and placement of an intra ocular lens (if considered feasible) in the capsule thus left behind.
Age related cataract can really not be prevented, the onset can be delayed by adhering to a balanced diet, vitamin and mineral supplementation to diet (antioxidants), prevention of excessive exposure to UV radiation by using good quality UV protected sunglasses, avoiding injuries to eyes where such professions increase susseptibility to injuries by using protective glasses, avoiding addictives, foods containing preservatives, etc.
Antioxidants are a group of essential vitamins, and minerals which prevent oxidative damage to the crystalline lens of the eye. Naturally occuring antioxidants are found in plenty in fruits and vegetables, but in certain areas these may be deficient due to the lack of such minerals in the soil in which they are grown. So supplementation of these vitamins and minerals is a must starting in the middle age of life.