Sociodemographic Factors May Affect Visual Impairment in Keratoconus

Race, insurance carrier, and smoking may affect visual acuity in patients with keratoconus.

Sociodemographic factors, which include Black race, government-funded insurance, and active smoking are associated with an increased risk of visual impairment in individuals with keratoconus, according to a study published in Cornea.

Researchers retrospectively reviewed records from 1989 patients with keratoconus who presented to the Wilmer Eye Institute between 2013 and 2020. The team examined sociodemographic factors among the cohort, which included age, sex, race, national area deprivation index, insurance carrier, and smoking status. Study participants underwent corneal topography assessment, which included flat keratometry (K1), steep keratometry (K2), mean keratometry, maximum keratometry (Kmax), and thinnest pachymetry. The primary outcome measure was visual impairment (visual acuity worse than 20/40) in the better-seeing eye.

Overall, patients who were Black had the highest risk of visual impairment — a risk that was more than double than that of participants who were White, according to the report (odds ratio [OR], 2.25; 95% CI, 1.71–2.95). Insurance carrier also affected visual impairment risk. Patients with Medicaid (OR, 2.59; 95% CI, 1.75–3.83) and Medicare (OR 2.48, 95% CI, 1.51–4.07) coverage demonstrated an elevated risk compared with individuals with private insurance. Active smokers were more likely to have visual impairment than those who did not have a history of smoking (OR, 2.17; 95% CI, 1.42–3.30). 

Kmax values were highest among participants who were Black (56.0 D; P =.003) and thinnest pachymetry (463.2 mm; P =.006) were lowest among these individuals compared with participants of other races. Patients who were Black also had the highest median area deprivation index (37.0; P<.001) compared with individuals of other races, indicating a higher level of socioeconomic disadvantage.

“Given that more severe disease at first presentation can not only affect the treatment options available but also prognosticate more rapid progression of the disease, we believe that these data warrant further investigation into the possible need for targeted screening programs to allow for earlier detection and possibly intervention with [corneal crosslinking] to preserve [visual acuity] and potentially mitigate previously identified disparities in rates of keratoplasty for [keratoconus] and visual impairment,” according to the researchers.  

Study limitations include an inability to age match the cohorts and potential confounding due to allowing patients to use contact lenses or spectacle correction during visual acuity assessment.


Nugent L, Son H-S, Wang J, et al. Racial variation in visual impairment of patients with keratoconus at presentation. Cornea. Published online June 9, 2023. doi:10.1097/ICO.0000000000003302