Optic Disc Features Associated with Grey Crescent Risk in Glaucoma

More than 1 in 10 patients with glaucoma with African ancestry had optic disc grey crescent, according to a new analysis of more than 10,000 individuals in the Primary Open-Angle African Ancestry Glaucoma Genetics (POAAGG) Study.¹

Investigators from the University of Pennsylvania suggest the cases were more frequent in younger subjects and those with diabetes, as well as in eyes presenting several ocular features, including optic disc tilt and beta peripapillary atrophy.

“The presence of grey crescent was associated with optic disc tilt, a sloping retinal region adjacent to the outer disc margin, and the presence of beta peripallary atrophy in this population with glaucoma,” wrote investigators.¹ “These associations should be taken into account when evaluating demographic and ocular characteristics in patients with POAG.”

The POAAGG Study was cited as the largest African ancestry POAG cohort recruited from a single city. From this dataset, the investigative team led by Ebenezer Daniel, MBBS, MS, PhD evaluated the prevalence of optic disc grey crescent among glaucoma cases and their possible associations with baseline demographic, ocular, and genetic characteristics.

The team hypothesized that higher African ancestry would be associated with the presence of grey crescents among glaucoma cases within the population. Previous findings from the POAAGG study population reported by the investigator team indicated a higher degree of African ancestry was associated with an increased POAG risk.¹

Stereo optic disc image features from subjects with glaucoma in the POAAGG study were evaluated independently by non-physician grades and discrepancies were adjudicated by an ophthalmoigist. The risk factors associated with the presence of grey crescent were evaluated using univariable and multivariable logistic regression models and intereye correlation was accounted for by generalized estimating equations.

In the POAAGG cohort, grey crescent was observed in 284 (9.9%) of 2866 eyes of glaucoma cases. Of 1491 cases, 227 (15%) had grey crescent, with 57 (4%) bilateral and 170 (11%) unilateral.

Results from the multivariable analysis suggest factors associated with grey crescent were younger age (adjusted odds ratio [aOR], 1.27; 95% confidence interval [CI], 1.11 - 1.43 for every decade younger in age; P = .001), diabetes (aOR, 1.46; 95% CI, 1.09 - 1.96; P = .01), and optic disc tilt (aOR, 1.84; 95% CI, 1.36 - 2.48; P <.0001).

In addition, a sloping retinal region adjacent to the outer disc margin (aOR, 2.37; 95% CI, 1.74 - 3.32; P <.0001) and beta peripalliary atrophy (aOR, 2.32; 95% CI, 1.60 - 3.37; P <.0001) were factors associated with grey crescent.

The findings indicate subjects with grey crescent had a lower mean value of the ancestral component q0 than patients without grey crescent (0.22 vs. 0.27; P = .001), consistent with higher degrees of African ancestry.

However, investigators noted that due to the continuing recruitment of additional POAAGG subjects after the completion of the genetic sample procurement, there were several missing values in the ancestry analysis.

“For this reason, we could not include ancestry for the multivariate analysis and therefore cannot say with certainty that this association is independent of other significant demographic associations,” they wrote.¹

References

1. Daniel E, Gao J, Maguire MG, et alPrevalence and factors associated with optic disc grey crescent in the Primary Open-Angle African Ancestry Glaucoma Genetics (POAAGG) StudyBMJ Open Ophthalmology 2023;8:e001183. doi: 10.1136/bmjophth-2022-001183