Neural retinal impairment linked to flicker light response

The impairment of vascular response to flicker lights could reveal inner retinal neural impairment in patients with diabetic retinopathy (DR), according to a study published in Investigative Ophthalmology and Visual Science.

Dr Pascale Massin et al., Department of Ophthalmology, Lariboisière Hospital, Paris, France, studied 28 normotensive, diabetic patients wihout DR and 28 healthy patients of the same age and sex as the control group. All patients underwent colour vision and contrast sensitivity tests, evaluation of the vascular reponse to flicker lights with the dynamic vessel analyser (DVA) and pattern, full field and multifocal electroretinogram (ERG).

It was found that diabetic patients experienced significantly impaired ERG pattern responses in comparison with the healthy subjects. This included the b-wave in the scotopic bright flash ERG, the a-wave and b-wave in the photopic single flash ERG. The vascular response to flicker light in diabetic patients compared to the control group was impaired.

Correlations were discovered between flicker light-induced arterial retinal vasodilation and the amplitude and implied times of the N95 wave of pattern ERG throughout the whole study group.

No strong correlation was found between the result of the diabetic patients, but it was concluded that neural and neovascular dysfunctions come before the start of clinically detectable DR.