A scanning laser ophthalmoscope (SLO) was used to examine the fundi of 54 diabetic patients through undilated pupils and the results compared by an experienced ophthalmologist with clinical examination through dilated pupils to assess the effectiveness of the SLO in detecting diabetic retinopathy. Whilst the SLO was not as good at detecting cotton wool spots and subtle intraretinal microvascular abnormalities, it did not miss any active new vessel formation and all eyes needing treatment would have been referred.