PURPOSE:To investigate the possible role of endogenous prostaglandins in the development of form deprivation myopia, as well as the effects of exogenous prostaglandins using atropine as a positive control. METHODS:Monocular form deprivation was accomplished by mounting a translucent occluder on one eye of 2-3 day old chicks for 1-4 weeks. Ocular occlusion for 1-2 weeks was used for pharmacological blocking experiments. The axial length of the eye was measured by ultrasonography. RESULTS:Indomethacin, administered intramuscularly, subconjunctivally or intravitreally had no significant effect on myopia development. Exogenous PGE2, PGF2alpha and latanoprost acid administered subconjunctivally, or topically as isopropyl ester eyedrops had no statistically significant effect on the myopia development. However, PGF2alpha significantly (p<0.01) attenuated the development of myopia after intravitreal injection. The other two prostaglandins had no statistically significant effect. CONCLUSIONS:Endogenous prostaglandins are unlikely to play a significant role in the development of form deprivation myopia in the chick. However, PGF2alpha suprisingly seems to retard the development of form deprivation myopia, but only when administered intravitreally. Whether the mechanism of the myopia retardation is direct or indirect remains unknown.