Keratoconus development risk factors: A contralateral eye study

Objective

The goal of this study is to evaluate risk factors for advanced keratoconus (KC) development using marked asymmetrical cases.

Methods

This is a prospective case-control contralateral eye study that evaluated 58 consecutive participants with very asymmetric KC from the department of cornea and external disease at the Porto Alegre Eye Bank Hospital, Brazil between March and November 2019. Risk factors for KC development were analyzed by patient interview (eye-rubbing behavior, atopic related diseases and identification of dominant hand), slit-lamp ocular surface examination and dry-eye tests. KC characterization was performed using the Pentacam® HR Scheimpflug tomography (Oculus GmbH, Wetzlar, Germany).

Results

The mean age of the participants was 27.17 ± 10.69 years (range: 16 to 56 years). Two thirds of patients presented history of allergic rhinitis. As expected, we found significant differences in BCSVA, K1, K2, Kmax and thinnest pachymetry (all P < 0.001) between cases and the contralateral eye. Reported eye-rubbing frequency was significantly higher in eyes with advanced KC (p < 0.001). Signs of blepharitis and dry-eye were very similar between both groups (p > 0.05). We observed no correlation between hand dominance and advanced KC laterality (p > 0.05).

Conclusion

This approach enabled us to examine a pure association between risk factors and KC development. Although we reported an increased patient-reported frequency of rubbing in eyes with advanced KC, we could not find any significant difference in ocular surface parameters (blepharitis signs and dry eyes tests) between cases and control that justified increased corneal manipulation.