Table 3

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 factorOR95% CIP value
 >551.00 (referent)
 <241.000.20 to 4.961.000
 25–396.381.56 to 26.100.010**
 40–544.000.96 to 16.610.056
 Female1.00 (referent)
 Male2.050.81 to 5.220.131
Contact lens wear habits
Contact lens type†
 RGP1.00 (referent)
 SDD3.930.34 to 38.700.241
 STWD10.000.78 to 128.780.077
 SMD5.310.56 to 50.550.146
 SEW2.500.10 to 62.610.577
Frequency of wear
 Few times a month1.00 (referent)
 Few times a week0.700.10 to 5.180.727
 Daily1.830.28 to 11.880.528
Hours of contact lens wear
 1–8 hours1.00 (referent)
 8–12 hours2.250.39 to 13.170.368
 12–18 hours3.530.63 to 19.80.152
 Continuous wear4.500.41 to 49.630.219
Sleeping in contact lenses
 No1.00 (referent)
 Yes3.141.15 to 8.630.026*
Frequency of sleeping in contact lenses
 Never1.00 (referent)
 Few times a year2.330.67 to 8.060.183
 Few times a month1.460.19 to 11.120.718
 Daily2.180.34 to 14.150.413
Showering in contact lenses
 No1.00 (referent)
 Yes3.131.16 to 8.470.025*
Frequency of showering in contact lenses
 Never1.00 (referent)
 Few times a year0.590.06 to 6.180.663
 Few times a month2.380.54 to 10.530.255
 Few times a week1.700.41 to 6.980.464
 Daily7.132.06 to 24.610.002**
Swimming in contact lenses
 No1.00 (referent)
 Yes0.850.34 to 2.130.723
Frequency of swimming in contact lenses
 Never1.00 (referent)
 Few times a year0.920.34 to 2.460.580
 Few times a month0.580.043 to 5.8740.229
Personal hygiene factors
Compliance with hand washing prior to handling contact lenses
 Always1.00 (referent)
 Most of the time0.390.14 to 1.100.075
 Occasionally0.410.04 to 4.850.482
How hands are washed
 Soap and water1.00 (referent)
 Water only1.270.48 to 3.340.628
Use of contact lens case
 Do not use case1.00 (referent)
 Use case1.070.42 to 0.270.894
Contact lens case storage location
 Bedroom1.00 (referent)
 Bathroom0.530.16 to 1.820.314
Frequency of replacing contact lens case
 Monthly1.00 (referent)
 1–3 months0.460.10 to 2.170.328
 3+ months1.940.51 to 7.320.329
Purchasing lenses and follow-up history
Where contact lenses are purchased
 Optician1.00 (referent)
 Internet0.550.09 to 3.180.500
 Other2.180.19 to 25.20.532
Were risks of infections explained when lenses were first prescribed?
 Yes1.00 (referent)
 No1.260.39 to 4.150.700
 Not sure0.850.30 to 2.390.758
Compliance with follow-up appointments (at least annually)
 Yes1.00 (referent)
 No1.200.47 to 3.070.700
Frequency of contact lens aftercare appointments with optician
 Every 3–6 months1.00 (referent)
 Every 6–12 months1.600.58 to 4.410.360
 Less than annually0.680.11 to 4.410.688
 Never1.090.24 to 4.030.911
  • **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.