Change in the appearance of elastin in the lamina cribrosa of glaucomatous optic nerve heads

Elastin fibers in the lamina cribrosa of glaucoma eyes have a curled appearance when the tissue is fixed at atmospheric pressure. To evaluate the effect of preparation conditions on elastin appearance, we set the eye pressure at one of four levels during tissue fixation in 18 glaucoma and 16 normal eyes. Glaucomatous damage was associated with an abnormal appearance of elastin at each pressure level. The majority of glaucoma eyes (11/18) had curled elastin profiles. In glaucoma eyes with definite nerve damage, elastin was graded moderately or severely abnormal in 47% (7/15), while in normal controls the rate of similar curling was 6% (1/16). The severity of abnormal elastin appearance was lower in glaucoma eyes that were fixed and frozen at higher intraocular pressures, but the difference was not statistically significant.