# Assessment of retinal and choroidal microvasculature in night shift medical workers by OCT angiography

## TL;DR

This study found that night shift medical workers have changes in eye blood vessels linked to lower melatonin levels, suggesting a higher risk of eye diseases.

## Contribution

The study identifies a correlation between reduced melatonin and microvascular changes in night shift workers using OCT angiography.

## Key findings

- Night shift workers had significantly decreased choroidal vascularity and flow deficit, and increased choroidal thickness.
- Lower melatonin levels were strongly correlated with thicker choroidal tissue and reduced vascular indices.
- Choroidal flow deficit was identified as a sensitive indicator of blood flow changes in the eye.

## Abstract

This study evaluated retinal and choroidal microvascular changes in night shift medical workers and its correlation with melatonin level. Night shift medical workers (group A, 25 workers) and non-night shift workers (group B, 25 workers) were recruited. The images of macula and optic nerve head were obtained by swept-source OCT-angiography. Vessel density of retina, choriocapillaris (CC), choriocapillaris flow deficit (CC FD), choroidal thickness (CT) and choroidal vascularity index (CVI) were measured. 6-sulfatoxymelatonin concentration was analyzed from the morning urine. CC FD and CVI were significantly decreased and CT was significantly increased in group A (all P < 0.05). 6-sulfatoxymelatonin concentration was significantly lower in group A (P < 0.05), which was significantly positively correlated with CC FD size (r = 0.318, P = 0.024) and CVI of the most regions (maximum r-value was 0.482, P < 0.001), and was significantly negatively associated with CT of all regions (maximum r-value was − 0.477, P < 0.001). In night shift medical workers, the reduction of melatonin was significantly correlated with CT thickening, CVI reduction and CC FD reduction, which suggested that they might have a higher risk of eye diseases. CC FD could be a sensitive and accurate indicator to reflect CC perfusion.