Anticoagulation and cataract surgery: a review of the current literature.

The anticoagulated patient presenting for cataract surgery presents many dilemmas for anaesthetist and surgeon alike. Current evidence suggests that warfarin therapy significantly improves prognosis in patients with atrial fibrillation with coexisting cerebrovascular disease, and those with non-tissue prosthetic heart valves. Inadequate anticoagulation in these groups exposes them to higher risk of systemic embolic complications, which are frequently devastating. Warfarin is an extremely complex drug. Attempted cessation and recommencement of warfarin therapy may not only reverse anticoagulation for unpredictable periods of time but may also expose patients to a transient yet dangerous hypercoagulable state. In most instances this state represents an additive risk to the untreated disease for which warfarin is being prescribed. It is difficult to accurately measure risks of local anaesthetic blockade in anticoagulated patients as techniques are not standardized. Smaller needles and single injections appear safer with deep eye blocks, while sub-Tenon's block and topical techniques appear safer still, and acceptable provided patients and surgeons are happy with the conditions so created. Retrobullbar haemorrhage appears to occur more frequently in anticoagulated patients who have their anticoagulation continued up to the time of cataract surgery. Retrobulbar haemorrhage is also more frequent in this same group even when anticoagulation is ceased prior to surgery when compared to non-anticoagulated patients. Prognosis for visual acuity with retrobulbar haemorrhage is generally good, given an experienced surgeon is present to rapidly decompress the eye.