Myopia Associated With Increased Risk of POAG

Myopia is associated with greater odds of developing primary open-angle glaucoma (POAG), according to a new study published in JAMA Ophthalmology. This association was strong in beneficiaries of Asian, Black, and Hispanic identity compared with non-Hispanic White beneficiaries.

Myopia, also known as nearsightedness, is a common refractive disorder, with the National Eye Institute estimating that 50% of the world’s population will have myopia by 2050. Myopia has been found in the past to be a possible risk factor for POAG, which is the most common type of glaucoma in the United States and the second leading cause of vision loss in the world. This study aimed to find the association between myopia and POAG in Medicare beneficiaries in California in 2019 and to determine whether race and ethnicity were associated with this relationship.

The population of the 2019 CA Master Beneficiary Summary File and the Standard Analytic Files of part B Carrier Claim files from CMS were used for the study. POAG was examined as either any POAG or no POAG and by severity levels of mild, moderate, and severe. Indeterminate stage and unspecified were also used as severity categories. Myopia was assessed using severity levels of no myopia, myopia without degenerative changes, and degenerative myopia.

Race and ethnicity were defined as Asian, Black, Hispanic, non-Hispanic White, and other (American Indian/Alaskan Native, unknown, and other race and ethnicity) using data from the California Medicare enhanced race and ethnicity codes. Participants were also characterized by age, sex, and systemic disease burden.

There were 60,211 beneficiaries within the California Medicare beneficiaries database who had myopia and 171,988 beneficiaries who had POAG. A total of 346,723 individuals identified as Asian; 117,856 as Black; 430,597 as Hispanic; 1,705,807 as White; and 115,363 as other out of the 2,717,346 California Medicare beneficiaries in the database.

Beneficiaries had elevated odds of POAG when they had myopia compared with beneficiaries without myopia (odds ratio [OR], 2.41; 95% CI, 2.35-2.47). Myopia was also associated with increased odds of contracting POAG in all racial and ethnic gropus, with the strongest associations seen in beneficiaries who identified as Asian (OR, 2.74; 95% CI, 2.57-2.92), Black (OR, 2.60; 95% CI, 2.31-2.94), and Hispanic (OR, 3.28; 95% CI, 3.08-3.48); those who identified as White had a lower association (OR, 2.14; 95% CI, 2.08-2.21).

Increased adjusted odds of POAG were found in beneficiaries who had myopia compared with those who were without (adjusted OR [aOR], 2.13; 95% CI, 2.07-2.19) and beneficiaries with degenerative myopia (OR, 4.19; 95% CI, 3.79-4.41). Myopia without degenerative changes compared with no myopia was associated with greater odds of contracting POAG in beneficiaries who were Black (OR, 2.49; 95% CI, 2.19-2.82) and Hispanic (OR, 3.15; 95% CI, 2.95-3.36) vs those who identified as White (OR, 1.84; 95% CI, 1.84-1.97).

Higher odds of all levels of POAG severity were found in those with myopia compared with those without:

• Other POAG: OR, 1.93 (95% CI, 1.86-2.01)
• Mild POAG: OR, 2.22 (95% CI, 2.14-2.23)
• Moderate POAG: OR, 2.32 (95% CI, 2.23-2.41)
• Severe POAG: OR, 2.91 (95% CI, 2.78-3.05)

This relationship was strongest in moderate and severe POAG for Asian beneficiaries and Hispanic beneficiaries compared with White beneficiaries:

• Asian beneficiaries:
  • Moderare POAG: OR, 2.64 (95% CI, 2.40-2.91)
  • Severe POAG: OR, 3.55 (95% CI, 3.18-3.96
• Hispanic beneficiaries:
  • Moderate POAG: OR, 2.84 (95% CI, 2.57-3.14)
  • Severe POAG: OR, 3.83 (95% CI, 3.45-4.26)

Limitations on these study findings include that specific diopters of refractive error could not be evaluated because only 2 levels of myopia were assessed, and diagnoses may not have been captured due to clinician coding. Also, the percentage of participants with observed myopia presence was substantially lower than in previous studies. Diagnostic suspicion and detection bias were possible.

The researchers concluded that those who had myopia had increased odds of contracting POAG based on the 2019 California Medicare population. Race and ethnicity played a role in POAG risk, with a higher risk of POAG and severe POAG in those of Asian, Black, and Hispanic descent.

Reference

Yao M, Kitayama K, Yu F, Tseng VL, Coleman AL. Association between myopia and primary open-angle glaucoma by race and ethnicity in older adults in the Californian Medicare population. JAMA Ophthalmol. Published online April 27, 2023. doi:10.1001/jamaophthalmol.2023.1007