Eye size and refraction in pigs with retinal degeneration

Purpose. To assess refraction and post natal eye growth in pigs with early severe retinal degeneration. Methods. At age ïmonths, five Pro347Leu rhodopsin transgenic pigs that had early severe retinal degeneration and five controls were examined under general anesthesia Aft :r mydriasis and cycloplegia with topical 1% atropine and 2 5% phenylephrine, refraction was assessed independently by two retinoscopists. Axial length was evaluated by A-scan ultrasound. After euthanasia, enucleated eyes were measured by digital calipers in axial, vertical and horizontal dimensions. Results. Transgenic pigs were more hyperopic than controls (+4 9 vs +2.1 diopters; p < 0 001; OD results only shown). On average, the eyes of transgenic pigs were shorter than contrcls (20 3 vs 213 mm, p < 0 05), chiefly due to a shorter vitreous cavity In the coroial view, transgenic pig eyes were slightly more elliptical than control eyes (p < 0 ('01), mainly because of a reduced vertical dimension Conclusions. Transgenic p gs with this phenotype of severe retinal degeneration develop short eyes and a hyperopic refractive error. Humans with retinal degenerations also develop chara:teristic refractive errors although comparable ultrasound data on human ocular compartments are limited. These results support the notion that retinal function influences post-natal eye growth.

Duke Scholars

Author Fulton Wong Ophthalmology