Prognosis for Cataracts

Posterior capsule rupture. This is one of the most common complications. It occurs in 1–3% of cataract operations. The posterior capsule is the transparent membrane encapsulating the lens and where the intraocular lens (IOL) must be implanted. There is a chance that a small volume of jelly-like fluid may seep out of the eye (a loss of vitreous humour) via a hole in the membrane and must be cleaned up using a special procedure (anterior vitrectomy). This can result in vision loss and other complications such as the inability to implant the IOL of choice, or the situation may require a second intervention.

Part of the cataract or the intraocular lens is lost or falls into the posterior cavity of the eye (the vitreous cavity); this usually requires a further intervention.

Intraocular bleeding, which could be mild and temporary (iris or vitreous haemorrhage), or severe and result in total vision loss (suprachoroidal haemorrhage). The latter complication occurs very rarely (less than 1 case in every 1,000 operations) with the application of modern phacoemulsification techniques.

Damage to other intraocular structures such as the iris or cornea.

Damage or loss of transparency in the cornea (the transparent window at the front of the eye), which is known as corneal oedema.

Swelling or “flooding” at the centre of the retina (cystoid macular oedema). This occurs in 3% of patients who undergo cataract surgery and is more common if other complications arise during the operation. It is normally treated with additional eye drops or other treatments, such as local corticosteroid injections or orally administered drugs. Patients may require weeks or months to recover, but occasionally it can entail a mild to moderate, yet permanent, loss of vision.

Retinal detachment, which may occur weeks, months or even years after the operation. The lifetime risk is 1 in every 150 patients who undergo cataract surgery, although it is more common in cases of high myopia or procedures that experienced perioperative complications such as posterior capsule rupture and loss of vitreous humour.

Glaucoma or increased intraocular pressure, which can be temporary or permanent.

Severe intraocular inflammation (uveitis).

Intraocular infection (endophthalmitis) is a very rare complication (less than 1 patient in every 1,000 operations), but it can lead to the irreversible loss of vision in the affected eye. Treatment involves the administration of intraocular injections, eye drops and oral antibiotics. Occasionally, another operation may be required.

Intraocular lens dislocation or decentration, due to insufficient support for the IOL implant (from the lens capsule) or because the IOL is defective.

Intraocular lens calcification or opacity, which affects its transparency. This is a rare complication that is associated with a certain type of material more than others.

Floaters, while these may be annoying and need to be checked out by an ophthalmologist, they are usually harmless. However, if you start to see flashes of light or the number of floaters increases, you should contact your ophthalmologist or go to an emergency department because these could be early signs of retinal detachment.

Drooping of the upper eyelid (palpebral ptosis).

Glare and halos around lights, which could be due to ocular inflammation or produced by the intraocular lens.

Pupil distortion or deformation so that is no longer round, or it is a different size from the other eye.

Double vision or difficulty maintaining eyes well aligned.

Residual refractive error, in other words, myopia, hyperopia or astigmatism following cataract surgery that were not predicted in preoperative calculations and which require the use of glasses, contact lenses, the replacement or adjustment of the intraocular lens or, on rare occasions, laser surgery to correct the error.

Dysphotopsia or undesirable optical phenomena due to artefacts that occur when light passes through or reflects on the intraocular lens. These occur relatively often. There are two types, either positive or negative. Positive dysphotopsias (glare, halos and starbursts) are caused by the shape of the edges of intraocular lenses. Negative dysphotopsias appear as dark arcs or crescent-shaped shadows in the patient’s peripheral vision and seem to be related to the specific anatomy of each patient’s eye. Most cases of dysphotopsia decrease or disappear over time. However, in 0.2–1% of patients the symptoms persist, and an intervention may be required to alleviate them.

In the months or years following surgery, the posterior lens capsule, which is the membrane that provides support at the back of the intraocular lens, may thicken or develop opacity. This is called posterior capsule opacification. It is the most common postoperative complication and causes a progressive loss of vision in 10% of patients within 2 years of undergoing a cataract operation. It can be treated on an outpatient basis using a laser in a very effective, rapid and painless intervention known as a YAG laser posterior capsulotomy; however, very occasionally, this procedure can cause retinal detachment or intraocular inflammation.