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Ocular and systemic causes of retinopathy in patients without diabetes mellitus

Most general practitioners and physicians are familiar with the risk factors, clinical presentation, and management of retinopathy in patients with diabetes mellitus, commonly termed diabetic retinopathy. Fewer doctors are fully informed about other ocular and systemic causes of retinopathy or the clinical significance of retinopathy in patients without diabetes (referred to as non-diabetic retinopathy in this review). However, retinopathy is fairly common in adults without diabetes,1–4 and doctors routinely encounter such patients in whom clinical or laboratory evidence of hyperglycaemia is consistently absent.

Although some patients with retinopathy will have an obvious aetiology (for example, severe anaemia, systemic lupus erythematosis, or underlying carotid disease), many do not have an easily identifiable cause for their retinal signs. What course of action should the doctor take when faced with retinopathy in a patient without diabetes? What are the common ocular and systemic causes of retinopathy? What is the clinical significance of these retinopathy lesions? These and other matters are discussed in this review.

We reviewed studies on ocular and systemic causes of “retinopathy” from Medline and textbooks. We specifically excluded “diabetic retinopathy.”

Non-diabetic retinopathy has been defined in different studies to include microaneurysms, retinal haemorrhages (dot, blot, and flame shaped), hard exudates, cotton wool spots, retinal venular abnormalities (venous beading and tortuosity), intraretinal microvascular abnormalities, and new vessels.1–3 The ocular and systemic causes of retinopathy in people without diabetes are varied (see table on bmj.com).

### Retinal vein occlusion

Central retinal vein occlusion and branch retinal vein occlusion can present with non-diabetic retinopathy. The appearance on funduscopy is usually characteristic, with flame shaped haemorrhages present within the distribution of the affected vein (fig 1). The patient may complain of a sudden painless unilateral loss of vision or visual field (for example, inferior field defects for superior branch retinal vein …