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

Objective: To compare the antimicrobial effects of locally available multipurpose contact lens solutions (MPS) on the growth of standard strains of contact lens-related ocular pathogens and to establish the recommended duration of exposure to these solutions to achieve maximal antimicrobial efficacy. Methods: This study, a single-blind controlled experiment, evaluated five locally available MPS in terms of their antimicrobial efficacy towards common contact lens-related ocular pathogens, such as P. aeroginosa, S. aureus, E. coli, F. solani, and C. albicans, using the stand alone criteria. Microbial viability counts were obtained at serial durations: after 1 hour, 3 hours, 6 hours, and 12 hours of exposure. Results: MPS containing polyquaternium-1 and myristamidopropyl dimethylamine (MAPD) and polyhexamide reduced the bacterial concentrations by 3 log and fungal concentrations by 1 log, enabling them to fulfill the stand alone criteria for disinfecting solutions as mandated by ISO/CD 14729. This antimicrobial efficacy was most evident at 6 hours of exposure to the challenge organisms. MPS containing polyquaternium-1 and MAPD also have the broadest spectrum of effectivity against gram-negative and gram-positive bacteria, and C. albicans. All MPS tested have poor microbial activity against F. solani. Conclusion Multipurpose contact lens solutions demonstrated variability in their antimicrobial activity. MPS with broad spectrum efficacy and effectivity, such as those containing polyquaternum and MAPD, are preferred to prevent contact lens-related ocular infections.
Contact Lenses

UV-absorption method was able to determine protease activities in various kinds of enzymatic cleaners. Bioclen G and O2 had high protease activeities at room temperature and were effective for artificial protein deposits; Bioclen G is safe for the eyes because enzyme was inactivated at 70 degrees C. Both products were better enzymatic cleaners for both hard and soft contact lenses. Hydrocare-F was effective for removing artificial protein deposits. For the sake of safety against the eyes, there was a problem in that this product had too high protease activity at 90 degrees C. Protease activities were generally lower or showed great variations at 10~30 degrees C for other products. These had lower cleaning effect for artificial protein deposits on rigid gas permeable contact lenses.
Contact Lenses* ; Contact Lenses, Hydrophilic

UV-absorption method was able to determine protease activities in various kinds of enzymatic cleaners. Bioclen G and O2 had high protease activities at room temperature and were effective for artificial protein deposits; Bioclen G is safe for the eyes because enzyme was inactivated at 70 degrees C. Both products were better enzymatic cleaners for both hard and soft contact lenses. Hydrocare-F was effctive for removing artificial protein deposits. For the sake of safety against the eyes, there was a problem in that this product had too high proteasea activity at 90 degrees C. Protease activities were generally lower or showed great variations at 10 ~ 30 degrees C for other products. These had lower cleaning effect for artificial protein deposits on rigid gas permeable contact lenses.
Contact Lenses* ; Contact Lenses, Hydrophilic

The times of uptake and release of pilocarpine solution by soft contact lenses were studied with spectrophometer in vitro. The uptake time was about 30 minutes and the releasing time was stationary after 30 minutes. The lower concentriction of pilocarpine solution was generally rapid uptake and release than higher.
Contact Lenses, Hydrophilic* ; Pilocarpine*

We compared the effects of astigmatism correction by toric lenses with that by hard contact lenses performing over-refraction in 14 eyes of 8 patients. The results are as following; 1) In 10 eyes, the effects were superior by toric lenses. 2) In 2 eyes, the effects were same. 3) In 2 eyes, the effects were superior by hard contact lenses.
Astigmatism* ; Contact Lenses* ; Humans

We compared the effects of astigmatism correction by toric lenses with that by hard contact lenses performing over-refraction in 14 eyes of 8 patients. The results are as following; 1) In 10 eyes, the effects were superior by toric lenses. 2) In 2 eyes, the effects were same. 3) In 2 eyes, the effects were superior by hard contact lenses.
Astigmatism* ; Contact Lenses* ; Humans

Objective. To create an age-based formula to estimate the base curve needed for contact lens fitting using measured central corneal curvature (CCC) with a handheld auto keratometer from ophthalmologically normal infants.

Methods. This is a prospective cross-sectional study involving 70 ophthalmologically normal full-term infants aged 0 to 12 months. The infants were divided into four groups: 0-3 months, >3-6 months, >6-9 months and >9-12 months. CCC was measured with a handheld auto keratometer and was used to compute for the base curve. Differences in CCC between the four groups were measured and linear regression models were used for formula creation.

Results. The mean CCC was highest in group 1 at 45.5 ±2.4 diopters (D). These values slowly decreased as age increased. A formula predictive of the base curve based on the infants age was derived using linear regression analysis. It predicted that for every month increase in age, there is a 0.063 millimeter increase in the base curve (p<0.001).

Conclusion. Infant CCC is highest at birth and gradually decreases as age increases. The formula can predict the base curve needed for contact lens fitting in infants without the need for a handheld autokeratometer.

Causative bacterias of keratitis due to mishandling of contact lenses are mainly Gram negative rods, and large percentage of them are Pseudomonas. We experienced 6 cases of culture-proven Pseudomonas keratitis due to mishandling of soft contact lenses and wetting solution can be cultured. They are lack of education as how handle the contact lenses safely. And they did not done disinfection of the soft contact lens cases. To prevent contact lens related keratitis, we think it is very important for users to know its possible complication and how to use it and disinfect it safely.
Bacteria ; Contact Lenses ; Contact Lenses, Hydrophilic* ; Disinfection ; Education ; Keratitis* ; Pseudomonas*

The clinical evaluation of the "O3/O4" series of Bausch and Lomb company for extended wear were performed in 138 eyes of 69 patients. In 128 eyes(92.1%) of them the corrected visual acuity over 0.8 was obtained and wearing periods of contact lenses were ranged from 1 day to 3 weeks (mean: 9.2 days). 117 eyes were satified with the contact lenses having no remarkable complications. There were no significant changes in corneal curvature between the examinations before and after contact lens wearing. From the above results, it can be suggested that the O3/O4 extended wear soft contact lenses are clinically available with excellent improvement of visual acuity.
Contact Lenses ; Contact Lenses, Hydrophilic* ; Humans ; Visual Acuity