This 63-year-old gentleman visited his optometrist with a one week history of ‘pixelated’ central vision from his right eye and he had developed some central distortion the day before his sight test.
This is a single image from an OCT scan of the right macula going from superotemporal to inferonasal through the fovea (left to right – see green arrow).
The most obvious abnormality is thickening of the left side of the scan, which corresponds to the area just superotemporal to the fovea. This area of thickening relates to the darker part of the infrared image. There is intraretinal fluid present and the inner retinal layers appear hyperreflective (brighter) on the affected part of the scan.
The most likely diagnosis is a right branch retinal vein occlusion (BRVO) with macular oedema. Haemorrhages are usually seen in the affected quadrant of the retina with associated dilation and tortuosity of the affected vein. The vein occlusion typically occurs at a point of arteriovenous crossing. The darker part of the infrared image is due to a combination of haemorrhage, intraretinal fluid and inner retinal oedema due to ischaemia, which accounts for the hyperreflectivity of the inner retinal layers in this area.
This patient was already on treatment for systemic hypertension (high blood pressure), which is the commonest systemic association of retinal vein occlusion. Routine investigations for patients with retinal vein occlusions include blood pressure measurement and the following blood tests: full blood count (FBC); erythrocyte sedimentation rate (ESR) and random glucose. Additional investigations may be indicated in patients under 50. Full guidelines on the management of patients with retinal vein occlusions can be found here.
This patient opted for initial observation as his visual acuity was relatively good (6/9) and there is a chance of spontaneous resolution of macular oedema due to retinal vein occlusion. He was reviewed a month later and the volume of macular oedema had increased as shown in the image below:
The visual acuity had dropped to 6/15 with increased distortion and the patient agreed to a loading course of intravitreal anti-VEGF injections.
Although image above shows a reduction in the volume of macular oedema, the patient reported a reduction in the quality of his vision, which had reduced to 6/18. He opted against further intravitreal injections at this stage.
The above OCT shows thinning of the affected area of the macula, which is due to loss of the inner retinal layers due to the ischaemia. The initial thickening, due to retinal oedema, followed by subsequent thinning is typical of vascular events causing retinal ischaemia, including retinal artery occlusions.
This patient’s vision has remained stable at 6/18. The lack of benefit from anti-VEGF in this patient was due to the ischaemic nature of the BRVO in his case. Most patients with macular oedema due to BRVO do benefit from anti-VEGF treatment.