A cataract is an opacity in the lens. It can have a number of effects. The cataract can reduce vision and patients may find it harder to read down a chart or read a car number plate. A cataract can result in frequent changes of glasses as the eye becomes more short-sighted when the lens hardens. A cataract can also cause glare as light is scattered when it hits the opacity.
In ageing the lens becomes darker. A patient is generally unaware of this occurring and it is only when the cataract is removed that the patient is aware that the vision in the operated eye is much brighter. Most people will have a degree of cataract after the age of 65. The presence of cataract in itself does not necessitate a surgical procedure. A decision to operate is made upon the patient’s lifestyle and visual function along with the presence of cataract.
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| Mature cataract | Nuclear cataract |
During an assessment for cataract a patient will have their vision assessed. It is useful to bring current spectacles and any note of a current spectacle prescription. The patient will be examined at the microscope and the pupils will be dilated to permit thorough examination of the lens and the retina.
Measurements will be made of both eyes to calculate the power of intraocular lens implant that will be used during subsequent surgery.
Surgery generally takes less than 20 minutes. The procedure will usually be done under a local anaesthetic and the patient will be able to go home shortly after the procedure.
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| Phakoemulsification of a cataract. | Insertion of a plate intraocular lens. |
Surgery will usually be done under a general anaesthetic if the patient is young, or apprehensive, or it is anticipated that the surgery may be more complex. Cataract surgery is subject to rigorous audit. In the absence of underlying pathology, the vast majority of cataract procedures result in restoration of a good level of visual acuity.
Graphics used by permission of the R.C.Opht. and Mardeno Patient Atlas