BeyHealth Quarterly Journal (BHQJ) BHQJ 2018: 001:1 (May 2018) - Page 8

CPD HOT TOPIC Diabetic Retinopathy – Diabetic Macula Oedema (DMO) & Proliferative Diabetic Retinopathy (PDR) DMO is the most prevalent cause of visual impairment in patients with diabetes. About 7% of diabetic patients have DMO of which 39% have associated visual impairment [4,5]. The typical characteristics of patients with DMO include long duration of diabetes, poor glycemic control, hypertension and hypercholesterolaemia [6,7,8]. Although DMO is often seen in association with non-proliferative diabetic retinopathy (NPDR), it can also be seen in association with proliferative diabetic retinopathy (PDR) (fig 1). Features of advanced NPDR with a high risk of imminent transformation to PDR include extensive retinal haemorrhages, microaneurysms, cotton wool spots, intraretinal microvascular anomalies (IRMA), and venous beading (fig 2). Fig 1: Macula oedema with microaneurysms, hard exudates and haemorrhages. Features of PDR with high-risk characteristics include new vessels on the disc (NVD) >1/3-disc area or new vessels elsewhere (NVE) > 1/2-disc area or vitreous haemorrhage. Mostly, findings on ophthalmoscopy include the clinical features listed above and may include fibrous proliferation. Often, significant pre-retina haemorrhage may be present and result in vitreous haemorrhage. In some cases, significant vitreous haemorrhage may cause vision loss and impair the view of the fundus on clinical examination. An ultrasound B scan can then be a useful tool in assessing the presence and extent of underlying retinal detachment due to vitreoretinal traction. This is illustrated in the figure below, showing a normal B scan and a B scan with significant echogenic vitreous due to a vitreous haemorrhage (fig 3,4). A potent insidious cause of loss of vision is tractional retinal detachment, which may commence in an extra-foveal site and then slowly involve the fovea, resulting in significant vision loss. In conditions of clear fundal view, a fundus fluorescein angiography can easily be obtained. Figure 5 illustrates areas of significant retinal and foveal ischaemia. Rubeosis and neovascular glaucoma is a severe presentation characterised by the development of neovascular proliferation within the anterior chamber (including the iris and anterior chamber angles) resulting Fig 2: Proliferative disease with large pre-retinal haemorrhage obscuring the macula. Visual acuity is in a severe rise in intraocular pressure, blindness and pain (fig 9). The optical coherence tomogram (OCT) provides a histological view of the diabetic retina. It is specifically used in the evaluation and monitoring of diabetic macula oedema (DMO). The macular thickness can be determined, including the presence of any traction in the macula. Fig 3: A normal B scan with an echo free vitreous cavity. 8 Fig 4: An echogenic vitreous is seen in this B scan. This is indicative of a vitreous haemorrhage. | MAY 2018 | Issue 1