Author: Dr Val Phua MBBS, MMed (Ophth), FRCOphth, FAMS
Photo by: Jean Beller
Modern day cataract surgery is a highly successful procedure to restore sight with a favourable outcome in 98% of patients. What is at stake for those who fall into the 2%?
Before the cataract surgery
Local anesthesia may be given by an injection around the eye and ensure a painless surgery and also to paralyse the eye. This can cause bleeding behind the eyeball, damage to the eye nerve and even damage to the brainstem if not done properly. With advances in cataract surgery techniques, it is possible to perform the surgery with just numbing eye drops, avoiding the risks involved with giving an injection around the eye. At times, your eye surgeon may feel it is safer to perform the surgery with the injection around the eye instead of just numbing eye drops.
During the cataract surgery
A complication that occurs <1% of the time is a posterior capsule rupture (PCR). This occurs when the bag in the eye opens up during surgery. This bag is very thin and fragile, measuring only 0.003mm thick. Modern cataract surgery machines have in-built mechanisms to stabilise the eye during surgery to minimise this risk. While PCR itself is not blinding, more time may be needed during surgery to deal with this complication because the down-stream effects of a poorly handled PCR includes higher risk of infection, retinal detachment and even corneal decompensation. Patients who do have this complication during surgery can still have good visual outcomes but a more prolonged recovery period to get there is needed. Other potential issues during surgery include the cataract falling to the back of the eye and corneal damage from the energy used to remove the dense cataract.
After the cataract surgery
One of the most feared complications is infection (endophthalmitis). This occurs when bacteria makes its way into the eye causing severe inflammation and damaging structures in the eye. This can result in severe visual loss and even blindness if left untreated. Fortunately, with modern day precautions taken to ensure sterility throughout the procedure, this risk is low at about 1 in 10’000 cases. Just to give you an idea about the precautions taken, this includes proper selection of patients to ensure there is no active infection of the eye and any diseases like uncontrolled diabetes are properly managed before surgery is done. The operating theatre environment is properly cleaned and equipment used in the surgery is thoroughly sterilised. The eye is cleaned before the surgery with an iodine solution which kills off bacteria and after surgery, antibiotic eye drops are given to prevent infection. In the rare case of an infection occurring, it should be promptly treated with antibiotic injections into the eye as well as strong antibiotic eye drops.
Another devastating complication is retinal detachment. This occurs when the retina (likened to the film in a camera) falls away from the wall of the eye. As you can imagine, light will no longer be captured properly resulting in poor vision. This should be promptly treated to restore as much sight as possible before irreversible damage to the retina occurs. The risk of this happening after cataract surgery has been estimated to be about 1 in 3000, higher in those with significant myopia.
In some patients, the inflammation that is associated with the surgery can result in swelling of the retina and again compromise vision. This is usually self-limited but does require a more prolonged treatment with anti-inflammatory eye drops.
While cataract surgery is only needed once and a cataract does not “re-grow”, some patients do develop blurred vision again after some time. This is also known as the “after cataract” and is due to growth of cells in the bag which used to hold the cataract. This condition does not require cataract surgery again to treat but rather a simple laser can be used to “clean it up”
The benefits of cataract surgery should always be weighed against the risks involved. With steps taken to optimise the entire surgical process and to minimise complications, a successful outcome with visually satisfied patients is the norm rather than the exception.