Experimental determination and allometric prediction of vitreous volume, and retina and lens weights in Göttingen minipigs

OBJECTIVES To determine the vitreous volume, and retinal and lens wet weights in male and female Gottingen minipigs of different age groups. PROCEDURES Vitreous, lens and retina were isolated from fresh minipig eyes. Vitreous volume, lens and retina weight were measured and allometric scaling was utilized to predict these parameters. RESULTS There were no gender differences in body weights or retina and lens weights in the three age groups examined in this study. For vitreous volumes, females had a significantly larger volume (approximately 10%-12%) than males in the 4-6 and 6-8 month, but not in the 8-11-month group. The mean body weight increased from 12.2 +/- 2.6 kg (4-6 months) to 19.4 +/- 4.0 kg (8-11 months). In the same period, the mean vitreous volume increased from 2.00 +/- 0.28 to 2.67 +/- 0.31 mL, while the mean retinal and lens weights increased from 114 +/- 22 to 126 +/- 17 mg, and from 298 +/- 26 to 392 +/- 15 mg, respectively. Allometric analysis between six species for vitreous volume and four species for lens weight covering a weight range of 260-fold was not able to estimate the vitreous volume, but it did predict the lens weight in 8-11 months minipigs. CONCLUSIONS Overall these measurements add important context to intraocular pharmacology studies, and will help in the improved design and interpretation of such experiments.