A recent study demonstrated that race could play a role in the rate of change in the surface depth of the lamina cribrosa during periods of IOP elevation, perhaps explaining some of the mechanisms ethnicity-specific susceptibility to glaucoma. Patients of African descent (AD) and European descent (ED) were observed in the evaluation study to determine how anterior lamina cribrosa surface depth (ALCSD) varied between the two groups over three years.
Researchers analyzed 1,122 images taken from 122 glaucoma patients, and differences between results for the two race groups were evident. The ED group had significantly greater ALCSD deepening than the AD group over the three years (difference= 2.57 µm/year). Despite this, the ED group had a shallower average ALCSD (−83.74 µm) than the AD group.
The remodeling response of the connective tissues of the optic nerve may be responsible for these racial differences. There are also known differences between ED and AD groups in susceptibility to glaucomatous injury and progression that could be related to the differing mechanical behavior of the lamina cribrosa.
Previous studies have shown an association between ALCSD remodeling and both glaucoma severity and aging. In one cross-sectional study, researchers observed deeper ALCSD in younger eyes and shallower ALCSD in older eyes. Now, this study is suggesting there may also be age-related remodeling differences between the racial groups. Specifically for individuals of African descent, researchers said that “increasing depth of the lamina cribrosa surface and thickening of the sclera was associated with increasing age.”
Greater posterior glaucomatous remodeling was seen in the ED group, while the AD group had greater age-related posterior migration of the ALCSD. However, further studies will be needed to validate these findings and determine whether race is playing a part.
“These studies suggest a complex relationship between lamina displacement due to normal aging and due to glaucoma that also varies across these racial groups with differential susceptibility to glaucomatous injury,” the researchers said in their paper.
For glaucoma patients of African descent, advanced age may be a risk factor for deepening ALCSD. More follow-up studies will help determine a relationship between race and both changes in the connective tissues of the optic nerve head and the progressive injury to the overlying neurovascular tissues.
Girkin CA, Belghith A, Bowd C, et al. Racial differences in the rate of change in anterior lamina cribrosa surface depth in the african descent and glaucoma evaluation study. Invest. Ophthalmol. Vis. Sci. April 2021;62(4):12.