Incorrect sleeping position and eye rubbing in patients with unilateral or highly asymmetric keratoconus: a case-control study

Abstract

Purpose To evaluate eye rubbing and sleeping position in patients with Unilateral or Highly Asymmetric Keratoconus (UHAKC). Methods Case-control study of consecutive UHAKC patients diagnosed at the Rothschild Foundation. Controls were age- and sex-matched, randomly selected refractive surgery clinic patients. Patients self-administered questionnaires regarding their family history of keratoconus, eye rubbing, and sleeping habits. All the eyes underwent a comprehensive ocular examination. Logistic regression was used to analyze univariate and multivariate data to identify risk factors for keratoconus. Results Thirty-three UHAKC patients and 64 controls were included. Univariate analyses showed that daytime eye rubbing [OR = 172.78], in the morning [OR = 24.3], or in eyes with the steepest keratometry [OR = 21.7] were significantly different between groups. Allergy [OR = 2.94], red eyes in the morning [OR = 6.36], and sleeping on stomach/sides [OR = 14.31] or on the same side as the steepest keratometry [OR = 94.72] were also significantly different. The multivariate model also showed statistical significance for most factors including daytime eye rubbing [OR = 134.96], in the morning [OR = 24.86], in the steepest eye [OR = 27.56], and sleeping on stomach/sides [OR = 65.02] or on the steepest side [OR = 144.02]. A univariate analysis in UHAKC group, comparing the worse and better eye, showed that eye rubbing [OR = 162.14] and sleeping position [OR = 99.74] were significantly (p < 0.001) associated with the worse eye. Conclusion Our data suggests that vigorous eye rubbing and incorrect sleeping position are associated with UHAKC. This is especially true in rubbing the most afflicted eye, and contributory sleep position, including positions placing pressure on the eye with the steepest keratometry.

Tear Film and Ocular Surface in Keratoconus

“…A controlled multivariate analysis by Bawazeer et al [59] identified eye rubbing as the single most important predictor of KC development, while the association between atopy and KC was attributed to the itching tendency experienced by atopic individuals. A number of case reports on unilaterally occurring keratoconus in patients with a corresponding unilateral habit of intense and repetitive eye rubbing, supports the concept that even normal corneas can become ectatic in response to rubbing-related corneal trauma [61,[109][110][111][112][113][114] (Table 3). However, observational case reports can only provide low level of evidence to infer a causative link.…”

Quantitative Interocular Comparison of Total Corneal Surface Area and Corneal Diameter in Patients With Highly Asymmetric Keratoconus.

“…It more likely represents a permanent corneal deformation with a relatively stable total surface area, and therefore may be considered as an extreme form corneal warpage caused by structural damage secondary to stromal degeneration and external forces [12]. We have previously shown that unilateral eye-rubbing and nocturnal compression on the same side can lead to UHAKC [7]. In this case-control study, we found that patients with unilateral or highly asymmetric keratoconus reported signi cantly more eye rubbing and more rubbing in the affected eye.…”

“…Inclusion criteria for unilateral or highly asymmetric keratoconus were patients with keratoconus in one eye and normal corneal topography in the fellow eye. As previously reported in our study [7], we used a combination of quantitative videokeratography-derived indices. We used Score (Score Analyser, Orbscan)…”

“…We enrolled 15 women and 65 men. All patients had unilateral or highly asymmetric keratoconus (UHAKC) as de ned in a prior study [7]. The right eye was either unaffected, or less affected in 35 patients (43.8%), as summarized in Table 2.…”

“…Keratoconus is a highly prevalent disease; however the pathophysiology is not yet fully understood. In recent papers, we proposed a primarily mechanical cause [3][4][5][6][7][8][9], with eye rubbing playing a fundamental role, with other known risk factors (biochemical, genetic, environmental) likely being associated with eye rubbing.…”