Spontaneous hyphaema in a patient on warfarin treatment.

We report a case of spontaneous hyphaema with no apparent predisposing cause except the assumption of an excessive warfarin dosage leading to overanticoagulation; a literature search performed in Medline revealed only one case of spontaneous hyphaema resulting from warfarin therapy and no other ocular cause [1]. In case of overdosing, the incidence of warfarin-related hyphaemas could be higher, and it should be taken into account in clinical practice. A 72-year-old woman presented complaining of blurred vision and discomfort in her right eye of 1 day\u2019s duration. She had been taking 5mg of warfarin sodium daily for atrial fibrillation for 2 years; she denied any other systemic disorder except hypertension and the historywas negative for eye disease or treatment. The International Normalized Ratio (INR)/dosing was stable and the INR was regularly monitored every 3\u20134 weeks. The patient\u2019s compliance with the regimen was good; two episodes of selflimiting subconjunctival haemorrhage during the previous 12 months were reported. There was no recent illness and no new concurrent medications. Slit-lamp examination of the right eye revealed diffuse heame within the anterior chamber and a 2-mm layered hyphaema. No iris abnormalities were present. Gonioscopy was unremarkable and dilated fundus examination was within normal limits for age. The left eye was normal. Haematological evaluation disclosed prolonged activated partial thromboplastic time of 73.4 s (normal range 26\u201336 s) and INR of 5.56 (normal range 0.80\u20131.20). By the consent of the patient\u2019s haematologist,warfarin was discontinued until a subsequent haematological evaluation 3 days later.At that time she was asymptomatic and visual acuity was normal (best corrected visual acuity 1.0 decimels, or 20/20 snellen). The anterior chamber had cleared completely; minimum blood was visible on the iris surface and within the anterior iris stroma at 6 o\u2019clock position. Gonioscopy and fundus examination were still negative for ocular abnormalities.Warfarin was reintroduced at a dose of 2.5 mg/day and the INR monitored 3 days later; the ocular bleeding has not recurred up to now.The use of the Naranjo probability scale revealed that the adverse event was possibly due to warfarin therapy (final score 4). Most spontaneous hyphaemas are associated with iris abnormalities, but this condition has been reported to occur froma variety of ocular causes