Eye and orbital size in the young and adult. Some postnatal experimental and clinical relationships.

The orbital volume in Dutch rabbits ranged from 3.6 ml at 98 days to 5.8 ml at 540 days of age. By 180 days of age the orbital volume had reached about its maximum of 5 ml and was 25% larger than at 100 days of age. The mean orbital volume was less at 540 than at 450 days of age. At 15 days of age the eye volume was about 20% of adult size, at 100 days of age about two thirds, at 180 days of age about 85% of adult size which was reached at about 300 days of age. The mean bulb volume was less at 540 than at 450 days of age. After evisceration, enucleation, or exenteration, in young rabbits there was a decelerated increase of orbital volume and a direct relationship between the lack of intraorbital mass and the subsequent lack of development of the orbit. The addition of a constant-sized implant in the young rabbit, after evisceration or enucleation of the eye, did not enhance orbital growth. In adult rabbits enucleation of the eye did not subsequently alter the orbital volume. In young rabbits an increase of the eye volume after multiple intrabulbar injections of silicone resulted in increase in orbital volume. The same procedure in adult rabbits increased neither the eye nor the orbital volume. Some clinical correlations are made.