Vision loss from glaucoma upon first presentation is more common among patients who are Black, those with high intraocular pressures (IOP), or those who have a history of diabetes, according to an investigation published in the American Journal of Ophthalmology. The study also shows low levels of education and single marital status can be significant risk factors for blindness upon first presentation for all glaucomas.
The study reviewed 3753 records of adults with glaucoma who visited the Duke Eye Center, in Durham, North Carolina, or affiliated satellite clinics between 2012 and 2019. The researchers identified 192 patients (5%) who were legally blind at first visit. The cross-sectional study included those with relevant diagnosis codes according to International Classification of Diseases (ICD), and excluded individuals with coexisting disorders that could affect sight. Blindness was defined corresponding to US Social Security Administration criteria: corrected visual acuity of 20/200 or worse (or visual field mean deviation of the better eye at ≤-22 dB).
Participants’ average age at baseline was 66.2 (SD 13.6) years, and mean IOP 18.1 (6.6) mm Hg; including 1755 diagnosed with primary open-angle glaucoma (POAG) and 1998 displaying other glaucoma types.
Compared with patients who did not present with vision loss from glaucoma, the blind cohort had a greater proportion of patients with Black ethnicities (65% vs 43%), who were unmarried (55% vs 42%), and who had a history of diabetes (18% vs. 9%), the researchers report.
Individuals who presented blind also had a higher mean average IOP, 19.9 (8.7) mm Hg, compared to the not-blind cohort, at 18.0 (6.5) mm Hg. Also, those who did have vision loss from glaucoma had a lower average annual income .
Multivariable analysis showed similar significant risks and trends as the univariable model, but only education as largely protective (P =.028). Two secondary analyses compared POAG vs other types of glaucoma. The multivariable model identified 2 significant risks for POAG; age per 10 years (P =.006), and Black ethnicity (P =.021). For vision loss from glaucoma types other than POAG, significant risk factors include higher mean IOP (P <.001), diabetes (P =.006), and Black ethnicity (P =.031).
“While race was a significant predictor of blindness in a multivariable model for both POAG and other glaucomas, higher IOP and history of diabetes were significant for other glaucomas but not POAG,” the researchers explain. They also report that some secondary disorders affecting younger persons may cause more rapidly advancing glaucoma.
Higher IOP, which influenced presenting with vision loss from glaucoma for other types of the disease may be due to the nature of this study’s tertiary clinic, where many individuals are referred who are already on IOP-lowering regimens, contrasted to secondary glaucomas that may entail higher IOP than primary disease.
Limitations of this analysis include diagnosis based on ICD codes — primarily used for billing, no subgrouping of new or existing diagnoses that indicates length of disease, as well as that income and education were ascertained by zip code rather than patient-level data, which was not available. Most prior research on vision loss from glaucoma involves outcomes during therapy, rather than the current study on risks to be blind when first seeking care.
Disclosures: A study author has declared affiliations with the biotechnology, medical device, and pharmaceutical industries. Please see the original reference for a full list of disclosures.
Shi A, Berchuck SI, Jammal AA, et al. Identifying risk factors for blindness from glaucoma at first presentation to a tertiary clinic. Am Jour Ophthalmol. Published online February 8, 2023. doi:10.1016/j.ajo.2023.02.006