Having a child with keratoconus (KC) may be an indication that parents’ corneal tomographic and biomechanical indexes show signs of the disease as well, even when the parents have not received KC diagnoses themselves, according to a study published in the American Journal of Ophthalmology. The parents of patients with keratoconus demonstrated characteristics such as reduced stiffness and thickness, although not all these findings manifested clinically.
Researchers conducted a prospective cohort study at a hospital in China. They compared parents’ corneal tomographic and biomechanical metrics of 88 parents of 44 children with keratoconus, and 84 parents of 43 children without keratoconus who had matching biomechanically corrected intraocular pressure (bIOP), age, and sex.
Based on the assumed prevalence of keratoconus in the first-degree relatives and the general population, the sample size presented a confidence level of 95% and a power of 80%.
Keratoconus diagnosis depended on abnormal tomography and at least 1 of the following: conical protrusion, Munson’s sign, Vogt’s striae, Fleischer’s ring.
Two individuals among the group of parents of children with keratoconus had bilateral keratoconus themselves. Tomographic examination revealed high anterior curvature and posterior elevation, skewed asymmetric bowtie, thinner central or paracentral cornea, and at least 1 of clinical findings. Each individual’s children had early onset of keratoconus, and their keratoconus could become severe in the future.
Mothers of patients who had keratoconus were more likely to also have keratoconus compared with fathers, according to the researchers.
Compared with healthy individuals, parents of patients with keratoconus were more likely to have suspicious biomechanical properties or pathological indicators on the Vinciguerra screening report.
“The novelty of our study lies in assessing subclinical KC characteristics in parents of KC patients and verifying the heritability of KC by combining corneal tomographical and biomechanical parameters,” the study authors report. “The observed abnormalities in biomechanical properties among the parents suggest a potential predisposition for the development of KC in their offspring.”
Study limitations include the sample size, the need for the equation to be validated in independent cohorts, and inability of imaging to replace genetic screening.
Li J, Zhang BN, Jhanji V, et al. Parental corneal tomographic and biomechanical characteristics of patients with keratoconus. Am J Ophthalmol. Published online August 10, 2023. doi:10.1016/j.ajo.2023.08.004