Cataract surgery is one of the miracles of modern medicine. Commonly performed, largely painless, with a rapid recovery in vision for the large majority of people who undergo the surgery. There are continuing advances in the precision of the surgery, and lens choices which are moving the state of the art forward.
Most cataract operations performed have eyes that are otherwise normal apart from the cataract. There are circumstances where the normal structures in the eye are compromised, which can make cataract surgery much more difficult to perform, and require more complex surgery.
In this example the patient had suffered an injury many years ago to the eye, known as a penetrating eye injury where the eye had been cut open by the injury. This injury required surgery at the time to close the laceration and save the eye. As a result of the injury there is a large scar in the cornea and approximately one third of the iris was lost. More importantly from the point of view of cataract surgery, approximately 40% of the zonules were damaged. The zonules are tiny thread like structures which hold the natural lens in place, and which form part of the structure supporting the artificial intraocular lens in the eye following cataract surgery.
More recently, this person noticed rapidly deteriorating vision and increasing glare. A dense cataract or clouding of the natural lens was found when the eye was examined. Because of the loss of the zonules, the new intraocular lens would require additional support to remain stable in the eye. When there is a small area of zonule loss, a capsular tension ring can be used to improve the lens stability. When a large area of zonules are lost, the capsular tension ring alone is not adequate to support the lens, as the CTR can only distribute the strength of the remaining zonules rather than add to the strength of the zonules.
In cases such as this the option is to implant a modified form of capsular tension ring where the ring is sutured to the wall of the eye. This Cionni ring increases the zonular strength and allows for a greater degree of stability of the intraocular lens following surgery. The video demonstrates how this procedure is performed. The patient had a good outcome with improved vision and reduced glare. Given the severity of the earlier injury the vision did not return to a normal level, however the vision achieved was useful to the patient and similar to that achieved after the injury occurred and before the cataract occurred.
There are a number of circumstances where cataract surgery can be more difficult due to zonule problems, iris problems and other abnormalities of the structure of the eye. As with all surgery it is important to tailor the surgical approach to the eye and to the needs of the individual.