Patients with a first-degree relative who has keratoconus are at an elevated risk of developing the condition themselves, according to a study published in Cornea.

“Being a first-degree relative of a subject with [keratoconus] remains a risk factor for developing [keratoconus]. This should be taken into account especially when screening for [keratoconus] in pediatric patients, for refractive surgery candidates, and for patients being evaluated for cataract surgery,” according to researchers.

The large epidemiological, prospective, and observational study out of the French KC National Reference Centre, in Bordeaux, looked at data from 94 unrelated patients with keratoconus, and at least 2 first-degree relatives. Patients had a thorough ocular exam, including for visual acuity, refraction, slit lamp biomicroscopy, indirect ophthalmoscopy, keratometry, corneal topography and tomography, pachymetry, and the biomechanical properties of cornea. Researchers also collected information on atopy, smoking, and eye-rubbing habits.

They found that, of 221 relatives, 9.05% (n = 20) had clinically manifest keratoconus, and 15.4% (n = 31) had subclinical. Prevalence was estimated as equal to: 0.14 [95% confidence interval (CI), 0.07–0.22] among parents, 0.03 (95% CI, 0–0.10) among offspring, and 0.10 (95% CI, 0.04–0.20) among siblings. Both age and eye rubbing were associated with an increased risk of keratoconus. “The familial correlation of [keratoconus] among probands’ first-degree relatives was estimated at 0.55 among parents, 0.29 among offspring, and 0.49 among siblings,” researchers reported.


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“Early screening should be proposed in relatives of patients with [keratoconus], and as such, we should sensitize the pediatric population on risks associated with eye rubbing in these families,” they say.

Reference

Lapeyre G, Fournie P, Vernet R, et al. Keratoconus prevalence in families: a French study. Cornea. 2020;39(12):1473–1479. doi: 10.1097/ICO.0000000000002546