Prostaglandin-induced iris color darkening. An experimental model.
OBJECTIVE
To determine the role of sympathetic innervation and the effect of topical prostaglandin therapy on iris color in pigmented rabbits.


METHODS
Twelve Dutch-belted rabbits underwent unilateral superior cervical ganglionectomy (SCGx) at age 1 to 3 months. A second group of 11 rabbits underwent bilateral SCGx at age 1 month and were treated once or twice daily for 6 to 9 months with 1 drop (about 20 microL) of latanoprost, 0.005%, to one eye and its vehicle to the contralateral eye. Standardized color photographs of the iris of each eye were taken at 1- to 2-month intervals for 6 to 10 months and evaluated by 4 to 6 observers in a masked fashion.


RESULTS
At 8 to 10 months after unilateral SCGx, 11 of 12 rabbits showed definite heterochromia, with the lighter-colored iris on the SCGx side. Of the 11 rabbits that underwent bilateral SCGx and unilateral latanoprost treatment, 9 showed heterochromia at 6 to 9 months, with the darker-colored iris on the latanoprost-treated side.


CONCLUSIONS
These results demonstrate that sympathetic innervation is required for age-related, physiologic darkening of iris color in rabbits, that prostaglandins may compensate for sympathetic denervation to produce darkening in SCGx eyes, and that this model may be useful to study prostaglandin-induced iris color change.
Department of Ophthalmology, University of Nebraska Medical Center, Omaha, USA.
G L
GL
Zhan
C B
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Toris
C B
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Camras
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Wang
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Bito
D000287:Administration, Topical; D000818:Animals; D005127:Eye Color / Q000187:drug effects / Q000502:physiology*; D005260:Female; D005728:Ganglia, Sympathetic / Q000502:physiology*; D015171:Ganglionectomy; D017495:Hyperpigmentation / Q000139:chemically induced* / Q000503:physiopathology; D007498:Iris / Q000187:drug effects / Q000294:innervation*; D000077338:Latanoprost; D008954:Models, Biological; D009883:Ophthalmic Solutions; D010781:Photography; D011461:Prostaglandins F, Synthetic / Q000008:administration & dosage / Q000494:pharmacology*; D011817:Rabbits
D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic; D000077338:Latanoprost