THE SHORT WAVELENGTH-SENSITIVE CONE ELECTRORETINOGRAM IN DIABETES - RELATIONSHIP TO SYSTEMIC FACTORS

The short wavelength-sensitive (S-) cone electroretinogram (ERG) is se lectively reduced in diabetic patients both with and without retinopat hy, but the exact machanism of the vulnerability of the S-cone system is still unclear. This study examined relationships of the S-cone ERG to systemic factors in diabetes. Cone ERGs to different color hash sti muli were examined in the presence of bright white background illumina tion in 17 diabetic patients without retinopathy and in 17 diabetics w ith background retinopathy. Relationships of the amplitude and implici t time of the S-cone ERG to the following systemic factors were statis tically analyzed: patients' age, hemoglobin Al level, method of diabet ic control, presence of retinopathy, and presence of nephropathy. The amplitude of the S-cone ERG b-wave was significantly reduced in diabet ics treated with insulin acid in those associated with nephropathy. No significant correlation was found between the S-cone ERG and patient' s age, hemoglobin A(1) level and presence or absence of retinopathy, A selective reduction of the S-cone ERG is observed in patients whose m etabolic control has been poor for a longer period, suggesting that mi crovascular changes may play a role in the S-cone ERG impairment.