This is the modern gold standard technique for removing a cataract. A small incision is made in the cornea, a special ultrasonic (phacoemulsification) probe is placed into the eye and the cataract emulsified and removed. An intraocular lens is folded and placed through the incision into the bag that held the natural cataractous lens.
Postoperatively, patients are usually prescribed a topical antibiotic and steroid combination for approximately four weeks.
Posterior capsule rupture
The capsule that surrounds the natural lens is left in place to support the new synthetic lens. Any weakness in this capsule can cause it to rupture and the vitreous to prolapse forwards. This vitreous is cleared away with an anterior vitrectomy.
More worryingly, sometimes there is no longer any support for the synthetic intraocular lens (IOL) in the capsular bag, which means the lens must be placed in the sulcus that is anterior to the capsular bag but behind the iris. This is not usually a problem and the patient can achieve good vision.
If the front of the capsule is also compromised, however, the patient may be left without a lens (aphakia) or have to have a lens placed anterior to the iris (an anterior chamber IOL). Anterior chamber IOLs can cause problems with the corneal endothelium, and the vision may not be as good as if the lens were placed behind the iris.
Sometimes a sutured posterior chamber lens is placed using sutures in the sclera.
Loss of lens fragment
If the posterior capsule ruptures before the cataract has been removed, part of it may fall into the vitreous cavity. If left in place, it will cause problems such as excessive inflammation and pressure rise. The fragment usually has to be removed with another operation – a vitrectomy and removal of lens fragments. These eyes are usually quite inflamed for longer and the vision may not be perfect.
Excessive postoperative uveitis
The eye is always inflamed after a cataract operation. Some patients develop excessive inflammation and require more than the usual four-times-a day steroid drops. It is always a concern that this excessive inflammation may be the start of an infective endophthalmitis.
Cystoid macular oedema
This is not uncommon after cataract surgery, particularly if the procedure was complicated. The blood retinal barrier in the macula breaks down and macular oedema develops, with consequent blurring of vision. The condition classically occurs about a week after surgery. Some cases resolve spontaneously, but others require treatment in the form of topical NSAIDs, oral acetazolamide or even peri-ocular steroid injections. Rarely, the condition fails to resolve and the patient is left with long-standing blurred vision. Patients are at risk of developing the same problem if they have cataract surgery to the other eye.
This is an ophthalmic emergency that requires immediate treatment, but is fortunately rare. The eye is red and painful, and the vision blurred. A vitreous tap is done to remove a sample for microbiological microscopy and culture. Antibiotics are injected intravitreally (into the vitreous cavity) to try to control the infection. Sometimes a vitrectomy is done in order to clear a heavy infective load. Some clinicians also advocate a short course of systemic steroids to control inflammation. Visual prognosis in established infection tends to be poor. A red painful eye with blurred vision after any intraocular surgery should be referred immediately.
This complication is rarer now in the days of small-incision surgery. A haemorrhage occurs in the layer between the choroid and the sclera. The blood accumulates in the wall of the eye and increases the intraocular pressure dramatically. When the eye is open, the ocular contents try to work their way out of the wound. If the haemorrhage is large, vision can be lost completely and permanently.
Posterior capsule opacification
This is not really a complication. It develops because epithelial cells remain in the old lens capsule and continue to grow. They spread across the posterior capsule behind the new intraocular lens and lead to blurry vision. A YAG laser capsulotomy usually clears the visual axis by burning a hole in the new layer.