Keratoconus is a progressive eye disease that results in thinning of the cornea, leading to visual impairment. Mitral valve prolapse (MVP) is a common disorder affecting around 2–4% of the general population. Previous studies have found an overrepresentation of MVP in individuals with keratoconus, with a prevalence of 38–65%, suggesting a shared underlying mechanism. In this case-control study, patients with keratoconus were enrolled from a quality and research registry. They were examined by a 2D echocardiography to identify if they had MVP, billowing or normal mitral leaflets. Controls were matched from the population-based Trøndelag Health Study. Patients and controls underwent a detailed echocardiographic examination to detect abnormal mitral valves. We included 101 patients (age 33 [IQR 29–40], 75% male) with keratoconus and 101 matched individuals. MVP was found in 2 (2%), while billowing was found in 5 (5%) of keratoconus patients. No significant association was found between keratoconus and the prevalence of MVP or billowing compared to the control group. Moreover, no associations were found between severity of keratoconus with presence of MVP nor with billowing of the mitral valves. We could not confirm the previously reported association between keratoconus and MVP, suggesting that routine screening for MVP in keratoconus patients may not be warranted. However, we cannot rule out the possibility of an association in other gender, age and ethnic groups different than ours.

Purpose: To examine whether there was an association between keratoconus and autism spectrum disorder (ASD) in Norway and compare with the general population. Setting: The total population of Norway, including all individuals with ASD and keratoconus. Design: Cross-sectional epidemiological study. Methods: Data were obtained from the Norwegian Patient Registry, which provides information from all publicly funded specialist care. The keratoconus prevalence among persons with ASD was estimated from the total number of individuals with keratoconus in the period 2010-2019 and compared with the prevalence in the general population of Norway during the same period. Results: A population-based sample in Norway identified 23 763 persons with ASD, equivalent to 0.5% of the population, and of these, 115 (0.5%) had a diagnosis of keratoconus. The average age at keratoconus diagnosis among individuals with ASD was 27.3 years, and 83.5% of those diagnosed with both ASD and keratoconus were men. During the same period, the prevalence of keratoconus in the general population of Norway was 0.2%, resulting in an odds ratio of 2.5 (95% CI 2.0-3.0). Conclusions: Based on our findings, people with ASD have significantly higher prevalence of keratoconus compared with the general population of Norway. This implicates that one should have increased awareness for keratoconus and low threshold for corneal tomography in patients with ASD.