Diagnosing and treating MacTel degenerative retinal disease

Idiopathic macular telangiectasia (MacTel) is a degenerative retinal disease that was described by Gass and Oyakawa in 1982.¹

Later, Gass and Blodi identified three subtypes of the disease.² In 2006, Yannuzzi et al. proposed a classification that is commonly used: aneurysmal (type 1), perifoveal (type 2) and occlusive (type 3).³ Type 1 appears to be a variant of Coats disease and type 3 is likely comprised of familial disorders with systemic associations. MacTel type 2 is the most common type and is the focus of this article.

 

Clinical features

MacTel type 2 is bilateral condition characterised by ectatic capillaries of the macula and atrophy of the neurosensory retina. Typically, the first clinical finding is decreased retinal transparency of parafoveal macula, often referred to as ‘retinal graying’. There are also crystalline deposits, depletion of the macular pigment and dilated macular venules and arterioles at right angles.

Atypical intraretinal and subretinal anastomoses may occur.³ Hyperplastic plaques of retinal pigment epithelium (RPE) may be found at the end of dilated vessels and are sometimes surrounded by atrophy of the RPE.

These plaques follow photoreceptor loss and are typically associated with an absolute scotoma. These changes occur just temporal to the fovea, initially, but may later expand to include the fovea.⁴

Neovascularisation of the retina can occur, as can small retinal haemorrhages with or without neovascularisation.⁴ The neovascularisation complexes originate from the deep capillary plexus, but may invade the subretinal space and rarely can form shunts with the choroid.²

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