Cilioretinal artery occlusion secondary to an evolving retinal vein occlusion

Abstract

A24-year-old woman presented with a 2-day history of sudden, painless, blurred vision in her right eye. Best-corrected visual acuities were 20/30, improving to 20/15 with pinhole in the right eye and 20/15 in the left eye. Anterior segments, intraocular pressures, and the left fundus were normal. Right fundal examination revealed a swollen, hyperaemic optic disc with mildly tortuous and dilated retinal veins. A few flame-shaped hemorrhages were present in the inferior fundus, with no signs of inflammation or macular edema. A mild, inferior hemiretinal vein occlusion (HRVO) was diagnosed. General medical examination and results of investigations, including full blood count, erythrocyte sedimentation rate, C-reactive protein, serum electrophoresis, clotting screen, antinuclear antigens, extractable nuclear antigens, homocysteine levels, fasting glucose, and lipid screen, were normal. She was a nonsmoker with no relevant ocular, medical, obstetric, or drug history. One week later, her right visual acuity had deteriorated to 20/30 and examination showed a mild central retinal vein occlusion (CRVO), with hemorrhages in all 4 quadrants. Fundus fluorescein angiography discovered both a CRVO and cilioretinal artery occlusion (Fig. 1). Management was conservative, and follow-up 2 months later revealed complete resolution of both CRVO and cilioretinal artery occlusion, with a best-corrected visual acuity of 20/15. Controversy still exists regarding the pathogenesis of the simultaneous CRVO and cilioretinal artery occlusion, which was first described in 1968.1 Some authors claim independent obstruction; others suggest that cilioretinal artery occlusion occurs secondary to CRVO, when increased retinal venous pressure causes a relative hypoperfusion of the cilioretinal artery.2,3 This case supports the latter theory, as our patient presented 1 week earlier with signs of an inferior HRVO and no cilioretinal artery occlusion. The recognition of this phenomenon and its likely pathogenesis will reduce unnecessary investigation of this secondary arteriolar occlusion.4 Furthermore, visual deterioration in these individuals may be partly the result of superimposed subclinical cilioretinal hypoperfusion due to raised venous pressure. Although it has been postulated that lowering intraocular pressures has little effect on perfusion pressures in CRVOs,5 this likely pathogenesis suggests that this approach may benefit the cilioretinal hypoperfusion and consequently, vision, in this specific subset of patients.