Research is uncovering yet another reason to keep the extra pounds off: a new study suggests carrying excess weight around the middle can influence a patient’s outer retina. Madrid researchers found cone-mediated dark adaptation (DA) slowed down as abdominal obesity increased. However, carrying around too much stomach weight might not be impactful to the inner retina, as researchers noted final contrast threshold was unaffected by abdominal obesity in healthy eyes.
Obesity has been associated with abnormal lipid metabolism and tissue hypoxia. This study examined the association between adiposity measures and the time course of DA measured psychophysically through contrast detection to test the functionality of both the outer and inner retina.
Researchers measured dark adaptation recovery of contrast threshold following near-total photopigment bleach for six minutes in 52 healthy eyes of 52 individuals. They reported cone time constant showed a positive correlation with waist circumference and waist-to-height ratio but not with body mass index. Additionally, only the waist-to-height ratio emerged as an independent predictor of time constant. The final final cone contrast threshold was not correlated with any adiposity measures, and mean cone time constant was 41 seconds slower in subjects (25%) with abdominal obesity.
In adult subjects, greater abdominal obesity waist-to-height ratio was related to a longer contrast recovery time for cone-mediated dark adaption, suggesting outer retinal dysfunction, researchers said. “Final contrast threshold, preferentially processed by inner retinal cells, was unaffected by abdominal obesity,” they added.
Additionally, intersession repeatability of contrast sensitivity recovery time constant was good, the study reported.
|Cinta PM, Antonio Alvarez FB. Abdominal obesity linked to a longer cone-mediated dark-adaptation recovery time in healthy eyes. Exp Eye Res. February. 6, 2019. [Epub ahead of print].|