Risk factors and severity of keratoconus on the East Coast of China

Purpose This study aims to investigate the characteristics, potential risk factors and associated severity of keratoconus on the east coast of China. Methods In this case-control study, patients diagnosed with keratoconus were invited to fill in the online electronic questionnaire designed with the help of the App named WenJuanXing. Several questions like, sex, age of diagnosis and eye care habits were administered to each subject through this e-questionnaire. Corneal topographies at diagnosis taken from Pentacam were also collected. Results Totally 391 Chinese keratoconus outpatients were enrolled in this study, among which 159 patients were newly diagnosed. Only three patients (0.77%) had a positive family history of keratoconus. Atopy could be identified in 66.0% of our patients. A total of 357 patients (91.3%) mentioned the habit of eye rubbing, with 191 patients (48.8%) rubbing their eyes frequently. Patients with younger age at onset (p = 0.005), male sex (p = 0.042), frequent eye rubbing (p = 0.003) and smoke (p = 0.002) were found significantly associated with increased risk of acute hydrops. In newly diagnosed patients, 79.9% had the maximum keratometry (Kmax) more than 52D, with males and patients aged 21-30 being even more serious (p = 0.009; p = 0.005). Besides, in patients aged over 21, frequent eye rubbing was significantly associated with steeper Kmax and more severe astigmatism (all p < 0.05). Conclusion Our results suggest that frequent eye rubbing is closely related to the severity of keratoconus in Chinese patients. Chinese keratoconus patients always had much serious disease condition at the time of diagnosis. Thus, increasing the publicity of keratoconus and advocating appropriate eye care habits are needed urgently in China. Registration The research was retrospectively registered, and the trial registration number is ChiCTR1900021273, and the registration date is 2019/02/09.