Alterations in anterior segment dimensions in eyes with retinitis pigmentosa.

BACKGROUND: In visually deprived primate eyes there is a correlation between alterations in growth parameters and changes in retinal neurotransmitters. Progressive retinal degeneration also leads to alterations in retinal neurotransmitters. In this study we wanted to investigate whether alterations in the dimensions of the anterior eye segment are also present in human donor eyes of patients with hereditary retinal degeneration. METHODS: Sagittal sections through anterior segments of 47 eyes from donors with different types of retinitis pigmentosa (RP) and of 59 eyes from normal donors were investigated morphometrically using a PC-based morphometric system. RESULTS: In the RP eyes there was a significant shortening of the distance between the peripheral end of Descemet's membrane and the posterior end of Schlemm's canal and of the length of the pars plana of the ciliary body. These changes varied markedly among the different types of RP. The most pronounced shortenings were found in eyes of men with X-linked recessive RP, which had the most severe retinal changes. RP eyes showed, in contrast to normal eyes, significant age-related elongation of the ciliary body and the chamber angle. A significant increase of the axial diameter with age was also found in RP eyes. CONCLUSION: Our study reveals for the first time that there are changes in the anterior segment dimensions in human eyes with hereditary retinal degeneration. Measurements of anterior eye segment parameters might provide additional indices for the severity of RP and for the diagnosis of RP subtypes.