An unusual case of posterior cerebral artery infarct in otherwise healthy man.

Sir,

We would like to share our experience by highlighting the role of an ophthalmologist in confrontation, automated perimetry, and clinical examination especially in patients with the high risk factors like diabetes and blood pressure as they can lead to silent infarcts and stroke. A 65-year-old male patient presented to the ophthalmology outpatient department with complaints of watering in both the eyes since 1 week.

On Ocular Examination visual acuity in both eyes (OU) was 20/40 (6/12) improving to 20/30 (6/9) with pinhole. His ocular movements were normal in all the gazes. Anterior segment examination including colour vision was within normal limits. Fundus examination revealed deep cup in both eyes with cup disc ratio of 0.3:1 in OD and 0.6:1 in OS. Rest of the fundus findings were within normal limits. On refraction the vision was improving to 20/30 with +2.75DS/-3.00 DCyl in OD and +1.50DS/-0.75 DCyl in OS. Intraocular pressure (IOP) by Goldmann applanation tonometer was found to be 14 and 15 mmHg in OD and OS, respectively. In view of asymmetrical cupping of optic disc, Humphreys perimetry was done which revealed left homonymous hemianopia [Figure 1]. Gonioscopy revealed open angles. Blood pressure was 140/90 mmHg. The neurological examination including higher functions was within normal limits. MRI showed an infarct in the area of the right occipital cerebral hemisphere and right cerebellum [Figure 2] MR angiography revealed a posterior cerebral artery infarct. The glycosylated hemoglobin was 10 mg% and rest of the blood profile including coagulation and lipid profile was altered. After cardiologist and neurologist opinion, he was prescribed vasodialators, statins, and advised strict control of his blood pressure and diabetes.

Figure 1

Humphreys visual field showing left homonymous hemianopia at first visit

Figure 2

Infarct in the region of right cerebral hemisphere and cerebellum

He followed up at every 15 days. At 12 week follow up, the Goldmann applanation tonometer readings were 29 mmHg in OD and 27 mmHg in OS. On subsequent followup his IOP remained consistently high and therefore he was investigated for open angle glaucoma. Central corneal thickness was 534 in the right eye and 532 in the left eye. The average RNFL thickness done by OCT was 71 in OD and 61 in OS. His HVF charting did not show any change. After another 1 month his intraocular pressure was 23 mmHg. He was started on Lumigan eye drop at bed time in OU. The intraocular pressure was 16 mmHg after 2 weeks of treatment and the visual field still remained the same. He has been on a regular two weekly follow up with us for past 1 year.

On reviewing the literature, no case of homonymous hemianopia with posterior cerebral artery infarct without ophthalmological and neurological symptoms was found. This is an unusual case where the patient presented with no neurological or visual field defect and turned out to be homonymous hemianopia with posterior cerebral artery infarct.

Uncontrolled diabetics and hypertensives are prone to microangiopathy in cerebral and optic nerve; there is a chance occurrence of these two together in this patient (Haris et al.).[1] Primary open angle glaucoma is associated with repeated transient ischemic injuries to the visual centers especially within the watershed zone. Due to the bitemporal defect, glaucoma may be masked and therefore these patients need to be followed up for a longer period of time, specially to rule out open angle glaucoma (Vermeer et al.).[2]

This case has been reported to mention the role of an ophthalmologist to emphasize the need for regular at least six monthly follow up to prevent further field loss in glaucoma patients with systemic disease like diabetes and hypertension. (Yucel et al.).[3]