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Editor,—Anterior segment ischaemia was first described by Schmidt1 in 1874 and later by Hayreh2 in 1979. It is a serious complication of squint3 and retinal detachment4 surgery. We present an elderly patient who developed anterior segment ischaemia after excision of conjunctival in situ squamous cell carcinoma. To our knowledge, this is the first reported case.
A 68-year-old Saudi man presented with a mass at the temporal limbus of the right cornea. He had previously undergone excision of a pterygium and a trabeculectomy in the same eye.
The patient’s medical history was suggestive of atrial fibrillation. Echocardiography showed no abnormalities and he was not receiving any treatment for cardiac disorders. Systemic examination was normal. Best corrected visual acuity was 20/70 in the right eye. Intraocular pressure was 12 mm Hg. Slit-lamp examination showed a vascularised, slightly elevated, reddish grey lesion extending from the 6 o’clock to the 11 o’clock position of the right limbus and invading 2 to 3 mm of the superficial cornea (Fig 1A). A filtering bleb was functional at the 12 o’clock position.
Complete excision of both lesions was performed, including a 2 to 3 mm free zone around the margin of the temporal lesion. Frozen sections of the same lesion showed in situ squamous cell carcinoma with all margins free of abnormality.
Five days postoperatively, visual acuity decreased dramatically with conjunctival injection, corneal oedema, Descemet membrane folds, anterior chamber flare, and a dilated non-reactive pupil. Intraocular pressure was 9 mm Hg. Investigations for uveitis and blood dyscrasia were unremarkable.
Anterior ischaemia was suspected. The patient was prescribed prednisolone acetate eyedrops (1%) every 3 hours. Four days later, visual acuity in the right eye improved to 20/200 with reduction of corneal oedema. Two weeks later, the intraocular pressure increased to 10 mm Hg after being 0 with minimal corneal oedema and minimal anterior chamber reaction. Posterior synechiae for 360º developed despite intensive therapy with sectorial iris atrophy (Fig 1B). The patient underwent cataract extraction with a final visual acuity of 20/50.
The eye in this case underwent an uneventful excision of a locally invading lesion with minimal bleeding, which was controlled with the wet field bipolar cautery. The cardiac rhythm, the blood pressure, and the pulse were monitored and observed to be at normal limits during the procedure. He reported 5 days later because of decrease in visual acuity, photophobia, and tearing. Mild anterior uveitis and corneal oedema resolved after intensive treatment with local corticosteroid drops.
The blood supply of the anterior segment of the eye has been described by several authors.5-9 Ocular hypotension in our case suggested interference with the arterial supply to the anterior uvea, indicating disruption of the major arterial circle. Damage to the anterior episcleral arterial circle secondary to the type of conjunctival incision used could explain the factors predisposing to the anterior segment ischaemia. The patient developed low intraocular pressure anterior uveitis, corneal oedema, mature cataract, posterior synechiae of 360º, and iris atrophy10 as a result of iris sector infarction. Another factor that could have predisposed to anterior segment ischaemia in our case was the trabeculectomy procedure, which possibly could have added to the damage of anterior episcleral arterial circle with poor compensation from the long posterior ciliary artery.
Anterior segment ischaemia after extensive or repeated surgery, especially in the elderly medically compromised, remains a risk. Early diagnosis and prompt treatment are of great importance in preventing permanent visual damage.
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