Independent risk factors for CLMK identified by univariate analysis, including patient demographics, contact lens wear habits, water exposure, hygiene practices and purchasing and aftercare follow-up history
| Risk factor | OR | 95% CI | P value |
| Demographics | |||
| Age | |||
| >55 | 1.00 (referent) | ||
| <24 | 1.00 | 0.20 to 4.96 | 1.000 |
| 25–39 | 6.38 | 1.56 to 26.10 | 0.010** |
| 40–54 | 4.00 | 0.96 to 16.61 | 0.056 |
| Gender | |||
| Female | 1.00 (referent) | ||
| Male | 2.05 | 0.81 to 5.22 | 0.131 |
| Contact lens wear habits | |||
| Contact lens type† | |||
| RGP | 1.00 (referent) | ||
| SDD | 3.93 | 0.34 to 38.70 | 0.241 |
| STWD | 10.00 | 0.78 to 128.78 | 0.077 |
| SMD | 5.31 | 0.56 to 50.55 | 0.146 |
| SEW | 2.50 | 0.10 to 62.61 | 0.577 |
| Frequency of wear | |||
| Few times a month | 1.00 (referent) | ||
| Few times a week | 0.70 | 0.10 to 5.18 | 0.727 |
| Daily | 1.83 | 0.28 to 11.88 | 0.528 |
| Hours of contact lens wear | |||
| 1–8 hours | 1.00 (referent) | ||
| 8–12 hours | 2.25 | 0.39 to 13.17 | 0.368 |
| 12–18 hours | 3.53 | 0.63 to 19.8 | 0.152 |
| Continuous wear | 4.50 | 0.41 to 49.63 | 0.219 |
| Sleeping in contact lenses | |||
| No | 1.00 (referent) | ||
| Yes | 3.14 | 1.15 to 8.63 | 0.026* |
| Frequency of sleeping in contact lenses | |||
| Never | 1.00 (referent) | ||
| Few times a year | 2.33 | 0.67 to 8.06 | 0.183 |
| Few times a month | 1.46 | 0.19 to 11.12 | 0.718 |
| Daily | 2.18 | 0.34 to 14.15 | 0.413 |
| Showering in contact lenses | |||
| No | 1.00 (referent) | ||
| Yes | 3.13 | 1.16 to 8.47 | 0.025* |
| Frequency of showering in contact lenses | |||
| Never | 1.00 (referent) | ||
| Few times a year | 0.59 | 0.06 to 6.18 | 0.663 |
| Few times a month | 2.38 | 0.54 to 10.53 | 0.255 |
| Few times a week | 1.70 | 0.41 to 6.98 | 0.464 |
| Daily | 7.13 | 2.06 to 24.61 | 0.002** |
| Swimming in contact lenses | |||
| No | 1.00 (referent) | ||
| Yes | 0.85 | 0.34 to 2.13 | 0.723 |
| Frequency of swimming in contact lenses | |||
| Never | 1.00 (referent) | ||
| Few times a year | 0.92 | 0.34 to 2.46 | 0.580 |
| Few times a month | 0.58 | 0.043 to 5.874 | 0.229 |
| Personal hygiene factors | |||
| Compliance with hand washing prior to handling contact lenses | |||
| Always | 1.00 (referent) | ||
| Most of the time | 0.39 | 0.14 to 1.10 | 0.075 |
| Occasionally | 0.41 | 0.04 to 4.85 | 0.482 |
| How hands are washed | |||
| Soap and water | 1.00 (referent) | ||
| Water only | 1.27 | 0.48 to 3.34 | 0.628 |
| Use of contact lens case | |||
| Do not use case | 1.00 (referent) | ||
| Use case | 1.07 | 0.42 to 0.27 | 0.894 |
| Contact lens case storage location | |||
| Bedroom | 1.00 (referent) | ||
| Bathroom | 0.53 | 0.16 to 1.82 | 0.314 |
| Frequency of replacing contact lens case | |||
| Monthly | 1.00 (referent) | ||
| 1–3 months | 0.46 | 0.10 to 2.17 | 0.328 |
| 3+ months | 1.94 | 0.51 to 7.32 | 0.329 |
| Purchasing lenses and follow-up history | |||
| Where contact lenses are purchased | |||
| Optician | 1.00 (referent) | ||
| Internet | 0.55 | 0.09 to 3.18 | 0.500 |
| Other | 2.18 | 0.19 to 25.2 | 0.532 |
| Were risks of infections explained when lenses were first prescribed? | |||
| Yes | 1.00 (referent) | ||
| No | 1.26 | 0.39 to 4.15 | 0.700 |
| Not sure | 0.85 | 0.30 to 2.39 | 0.758 |
| Compliance with follow-up appointments (at least annually) | |||
| Yes | 1.00 (referent) | ||
| No | 1.20 | 0.47 to 3.07 | 0.700 |
| Frequency of contact lens aftercare appointments with optician | |||
| Every 3–6 months | 1.00 (referent) | ||
| Every 6–12 months | 1.60 | 0.58 to 4.41 | 0.360 |
| Less than annually | 0.68 | 0.11 to 4.41 | 0.688 |
| Never | 1.09 | 0.24 to 4.03 | 0.911 |
**p<0.05. **p<0.01.
†Two contact lens types unknown and excluded in this analysis.
RGP, rigid gas permeable; SDD, soft daily disposable; SEW, soft extended wear; SMD, soft monthly disposable; STWD, soft 2-week disposable.