Introduction: Microbial keratitis is one of the most challenging complications of contact lens (CL) wear. Proper CL practice plays an important role to reduce the risk for contact lens related microbial keratitis (CLRMK). Methods: This multi-centre case-control study was conducted from January 2008 until June 2009 to determine the risk factors associated with CLRMK. Cases were defined as respondents who were treated for CLRMK, whilst controls were respondents who were contact lens wearers without microbial keratitis. Ninety four cases were compared to 94 controls to determine the risk factors for CLRMK. Results: The predictors for CLRMK were: Not washing hands with soap before handling CL (aOR 2.979, CI 1.020, 8.701 p=0.046), not performing rubbing technique whilst cleaning the CL (aOR 3.006, CI 1.198, 7.538 p=0.019) and, not cleaning the lens case with multipurpose solution daily (aOR 3.242 CI 1.463, 7.186 p=0.004). Sleeping overnight with the CL in the eye (aOR 2.864, CI 0.978, 8.386 p=0.049) and overall non-compliance with lens care procedures (aOR 2.590, CI 1.003, 6.689 p=0.049) contributed significantly to CLRMK. Conclusion: Health education and promotion in contact lens care are important and should be conducted by eye care practitioners to reduce the occurrence of CLRMK.
Contact Lenses

Introduction: A hospital based case control study was conducted in government hospitals on contact lens patients diagnosed with microbial keratitis. Methods: The objective of this study is to determine the visual outcomes of contact lens related microbial keratitis. The visual outcomes which comprised of visual acuity, keratometry readings, corneal topography findings and contrast sensitivity examinations was determined after three months from the first presentation at the hospitals. Results: The mean LogMAR visual acuity during presentation was 0.96 ± 0.73 or a Snellen equivalent 6/60 (n=76) and mean LogMAR visual acuity after three months was 0.10 ± 0.48 or a Snellen equivalent 6/7.5 (n=76) with a significant difference (t=11.22, df=78, p=0.001). Best fit curve for the cases had a regression coefficient, r=0.350 ± 0.063 (95% CI = 0.224, 0.447, df=78, p=0.001. The visual acuity in cases and controls was 0.10 ± 0.48 and -0.10 ± 0.14 respectively (t= -3.61, df=154 p=0.001) after three months which showed improvement. There was a reduction in the corneal uniformity index and corneal asphericity in the cases. The Corneal Uniformity Index (CU index) in cases was 63.03 ± 26.38 (n=76) and in controls, 80.13 ± 11.30 (n=77), (t= -5.22, df=151, p=0.001). There was also a reduction in the contrast sensitivity function at all spatial frequencies in the cases which was significantly different. Conclusion: Microbial keratitis reduced the vision, corneal uniformity index, asphericity and contrast sensitivity after three months in eyes of patients diagnosed with the condition.
Keratitis ; Eye