Aims: This scoping review was conducted to investigate whether nocturnal eye compression from inappropriate sleeping postures may contribute to the development or asymmetry of keratoconus (KC), by examining the association between sleeping positions and KC.
Material and Methods: A systematic search of CENTRAL, MEDLINE, EMBASE, LILACS, ClinicalTrials.gov, gray literature, and selected journals from inception to January 18, 2023, was undertaken.
Results: Ten studies involving 2 322 participants met inclusion criteria. These studies were categorized into analytical and non-analytical designs to evaluate the relationship between prone, lateral, or supine sleeping positions and KC presence or asymmetry. Among the included studies, 50% were non-analytical, all indicating a correlation between KC parameters and nocturnal eye compression. In contrast, a statistically significant association between sleeping positions and KC risk was reported in 3 out of 5 analytical studies (60%).
Conclusion: Findings suggest a possible link between prone or lateral sleeping positions and KC development or asymmetry, implying that these positions may increase corneal biomechanical stress during sleep. However, the association was confirmed in only 60% of analytical studies. The review highlights the necessity for additional research to validate these findings and to explore potential causal mechanisms between sleeping positions and KC.