Effects of photoperiod and food on glucose intolerance and subsequent ocular pathology in the fat sand rat

This preclinical study used diurnal fat sand rats (Psammomys obesus) to investigate how photoperiod (short vs. natural) and diet (standard rodent diet vs. lab extra-fine diet) affect glucose intolerance and ocular pathologies. Central results show that short photoperiod significantly worsened glucose tolerance and led to retinal pathology, including fewer cells in the outer nuclear layer, reduced total retinal cells, increased retinal thickness, and more severe cataracts. These effects were exacerbated by the standard rodent diet. Higher blood glucose levels correlated with more severe retinal changes. The study suggests circadian disruption has both direct effects on the eye and indirect effects via metabolic abnormalities. Limitations include the exclusion of intraocular pressure data due to measurement issues and the exclusive use of male animals. The findings highlight the potential of the sand rat as a model for studying modern lifestyle-related circadian disruption in diabetic eye disease.