Bruch's membrane thickness not related to axial length

Bruch's membrane thickness is not related to axial length in highly myopic eyes, and axially elongated eyes - despite having thinning of the sclera and choroid - have a normal Bruch’s membrane thickness.

Researchers from the departments of ophthalmology at Medical Faculty Mannheim, Heidelberg University, and Friedrich-Alexander University Erlangen-Nürnberg, used a light microscope to measure Bruch′s membrane thickness, as well as the thickness of the choroid and sclera, of 54 enucleated human globes. Of the eyes studies, 42 had optic nerve damage caused by glaucoma. The axial length of the eyes ranged from 21.0 to 34.0 mm, with a mean of 26.6 ± 3.3 mm. Twenty-three of the globes had an axial length of ≥26.5 mm.

The researchers examined horizontal anterior-posterior histological sections of the eyes, and compared Bruch's membrane thickness in the pars plana region, at the equator, at the midpoint between the equator and the posterior pole, in the parapapillary region, and at the posterior pole.

They found that Bruch’s membrane was thickest at the pars plana and, unlike choroidal and scleral thickness, was not significantly related to axial length (P > 0.45). When comparing non-glaucomatous non-highly myopic eyes and glaucomatous non-highly myopic eyes, and non-highly myopic eyes and highly myopic eyes, the researchers found no significant difference between the groups in Bruch’s membrane thickness at any point at or behind the ora serrata (P ≥ 0.40).

To view an abstract of the study, which was published in Acta Ophthalmologica, click here.