Risks of Surgery

Cataract surgery is one of the most successful procedures in modern medicine. More than 99% of patients experience an improvement in their vision. However, even in the best hands complications may still occur.

Tears of the posterior lens capsule.

The lens capsule is the transparent bag which surrounds the lens. During cataract surgery a circular hole is torn in the front surface of the capsular bag so the surgeon can then remove the cloudy lens material. Every effort is made to preserve the remainder of the capsular bag so that the implant lens can be placed in this bag once the cataract has been removed. Tears in the back (posterior) of the capsular bag occur in approximately 2-3% of cases (Royal College of Ophthalmologists National Audit 1997). Although the complication rate for surgery carried out by a Consultant Ophthalmologist is often closer to 0.5%.

Should this complication arise it is usually still possible to place an intraocular lens on top of the remaining capsule. Very occasionally a small piece of lens material falls into the vitreous jelly, if this happens a second operation may be necessary to remove this lens material.

Choroidal Haemorrhage

Bleeding within the layer of blood vessels that nourish the retina is a very rare and unpredictable complication of cataract surgery. If the bleeding is localized the eye may recover but in mores severe cases permanent, severe visual loss may occur.

Endophthalmitis (infection inside the eye)

This is potentially the most serious complication of cataract surgery, but fortunately it is also the least common (approximately between 1 in 1,000 to 1 in 1,500 operations). Every precaution before, during and after surgery is taken to prevent the development of endophthalmitis. The first signs and symptoms are of increasing pain, redness and deteriorating vision in the first 5-7 days after surgery. If these symptoms occur you should contact your surgeon immediately.

Posterior vitreous detachment and retinal detachment
(see A-Z for further details)

Cataract surgery slightly increases the risk of posterior vitreous detachment and subsequent retinal detachment.

Myopic patients and those who suffer a posterior capsule rupture during surgery are at greater risk that normal sighted patients or those who have uncomplicated surgery. New floaters in your field of vision and flashes of light are warning signs and if they occur you should contact your surgeon immediately.

Cystoid macular oedema (CMO)

The centre of the retina that serves detailed central vision is called the macula. After routine cataract surgery inflammation may cause swelling in this area of the retina, which is referred to as cystoid macular oedema. This condition results in blurred central vision 3-6 weeks after surgery and in the majority of cases resolves without treatment after 2-3 months. Occasionally anti-inflammatory drops or tablets may be prescribed to speed up recovery.

Intraocular lens errors

During cataract surgery the strength of the intraocular lens implant is chosen to help correct any previous long or short sightedness. The aim of surgery in most cases is to provide good distance vision with no glasses, or just a weak spectacle correction, but reading glasses will be needed for close work. Although the equipment used to calculate the strength of the implant is very accurate there is still the possibility that small errors can occur, especially in very long or short sighted eyes. This may mean that following surgery you may be slightly more long or short sighted than your surgeon had planned. In very rare cases a second operation may be needed to replace the implant with one of a different strength.

Posterior Capsule Opacification (PCO)

Thickening of the posterior lens capsule occurs in approximately 1 in 4 patients following cataract surgery. If you notice a gradual decline in vision 1-2 years after cataract surgery this is the most common cause. PCO is often detected by your optician who will then refer you back to the clinic for laser treatment (Link to Yag capsulotomy document). This is carried out using a laser mounted on a slit lamp. Treatment only takes 2-3 minutes to carry out and is painless.