At the present time, there is no effective medical treatment for cataract in spite of a number of claims over the years. A recent report has suggested that oral aspirin can delay the progress of cataract in female diabetics. Although this might be expected to have some effect on theoretical grounds, any benefit is probably marginal. Occasionally, patients claim that their cataracts seem to have cleared, but such fluctuation in density of the lens opacities has not been demonstrated in a scientific manner. Cataracts associated with galactosaemia are thought to clear under the influence of prompt treatment of the underlying problem.

Cataract is, therefore, essentially a surgical problem, and the management of a patient with cataract depends on deciding at what point the visual impairment of the patient justifies undergoing the risks of surgery. The cataract operation itself has been practiced since pre-Christian times, and developments in recent years have made it safe and effective in a large proportion of cases. The operation entails removal of all the opaque lens fibres from within the lens capsule and replacing them with a clear plastic lens.

In the early part of the last century the technical side of cataract surgery necessitated waiting for the cataract to become "ripe". Nowadays no such waiting is needed and it is theoretically possible to remove a clear lens. The decision to operate is based on whether the patient will see better afterwards. Modern cataract surgery can restore the vision in a remarkable way and patients often say that they have not seen so well for many years. Indeed, many patients have quite reasonable vision without glasses but this cannot be guaranteed and, because the plastic lens implant gives a fixed focus, glasses will inevitably be needed for some distances. Probably the worst thing that can happen after the operation is infection leading to endophthalmitis and loss of the sight of the eye. Although this only occurs in about one out of a thousand cases, the patient contemplating cataract surgery needs to be aware of the possibility. Before the operation, it is now a routine to measure the length of the eye and the corneal curvature. Knowing these two measurements, one can assess the strength of lens implant that is needed. When deciding on the strength of implant, it is necessary to consider the other eye. The aim is usually to make the two eyes optically similar because patients find it difficult to tolerate two different eyes.

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