Melanopsin in ocular tissue after corneal abrasion

Melanopsin is a non-image forming photoreactive protein that has diverse roles in multiple tissues. This study examines how melanopsin expression changes after corneal abrasion. Corneal abrasion is the most common form of eye injury and can cause severe pain and photoallodynia. Behavior of rats was measured using orbital tightening, a part of the grimace scale. Then melanopsin positive cells in the retina were counted and volume of melanopsin in the iris was calculated at baseline, 24h and 1wk. Finaly the prominence of the pupillary ruff into the pupil was measured. These data indicate that pain behaviors, melanopsin in the iris and prominence of the pupillary ruff all peak at 24h after corneal abrasion.