Cataract surgery is the most commonly performed ophthalmic surgical procedure worldwide.
Technological advances in equipment and techniques together with the development of foldable intraocular implants has resulted in the ability to perform small incision, sutureless cataract extraction and implant insertion, with a low incidence of complications. By calculating the appropriate power of the intraocular implant to be inserted it is possible to adjust the eye’s refractive power with a high degree of accuracy. This form of surgery has been taken one step further with Refractive Lens Exchange. Essentially this is the same procedure as carried out with a cataract extraction (except that the removed lens has no cataract and is therefore clear) together with the insertion of an intraocular implant. The power of the implant to be inserted is calculated to give as close a final prescription to zero as possible, thereby correcting the underlying refractive error.
Surgery is performed as a day case under local anaesthetic. There is usually very little pain or discomfort following surgery.
Refractive Lens Exchange is an alternative procedure for patients (usually over the age of 40) who may prove to be unsuitable for excimer laser surgery (especially individuals with high degrees of short sight or long sight that may be beyond the safe treatment limits with excimer laser). It may also be a more appropriate procedure for individuals who have early signs of cataract development.
Newer types of implants, such as accommodating or multi-focal lenses, can help give suitable patients not only good distance vision but also good near vision without the need for glasses. It is also possible to use toric implants to correct astigmatism
Phakic implants are similar to the implants inserted after cataract or refractive lens exchange. With phakic implants however, the patients own lens is not removed but augmented with the addition of a synthetic intraocular implant.
Whilst intra-ocular implants have been in use for many years after cataract surgery, phakic implants are a relatively new development in refractive surgery. They are used in patients unable to be treated with LASIK, especially individuals with very high degrees of short sight.
Phakic implants are able to correct large refractive errors because the lens can be made to a high power, and does not rely on altering the corneal shape to produce its optical effect. Since the patient’s own lens is not removed, the ability to accommodate and focus on near objects is preserved. This is particularly beneficial to those younger individuals who have not yet developed presbyopia.
Phakic implants are inserted into the eye through a small incision, usually in the cornea. The implant is placed behind the iris through a dilated pupil and sits in front of the eye’s natural lens. Surgery is carried out under local anaesthesia as a day case procedure.
This procedure consists of making relaxing incisions into the mid-periphery of the cornea. In astigmatism the corneal shape is not symmetrical. It tends to be steeper in one direction (like a rugby ball). Relaxing incisions allow the steep axis to flatten and improve the overall corneal shape. For some individuals who have astigmatism without any other significant refractive error this procedure may be appropriate to improve their unaided vision. It may also be used as an adjunctive treatment to other forms of laser or surgical vision correction where there are high degrees of astigmatism.
Treatment is carried out with anaesthetic eye-drops as a day case procedure.
As with all surgical procedures, there are certain risks and complications involved, see the ‘Risks and Complications’ section.