TABLE 4.
Lens Case Bioburden
| Study | Sample size and type | Lens type | Disinfection systems used | Frequency of sterile cases (%) | Frequency of author defined case contamination (%) | Frequency of contamination (%)
|
||
|---|---|---|---|---|---|---|---|---|
| Bacteria | Fungi | Protozoa | ||||||
| Case wells | ||||||||
| Gray et al.72 | 101 asymptomatic daily wear patients | 86 (85%) soft lens; 15 (15%) rigid | Peroxide (75%); chemical (23%) | 19 | 81 | 77 | 24 | 20 (Acanthamoeba sp 8) |
| Pens et al.88 | 81 contact lens wearers | NR | NR | NR | 80.1 | 71 | NA | Acanthamoeba spp 8.9 |
| Fleiszig and Efron18 | 41 contact lens wearers | Rigid and soft | Various | 29 | 71 | 71 | NR | NA |
| Solution in cases | ||||||||
| Midelfart et al.105 | 21 asymptomatic medical students | 20 (95%) soft lens, 1 (5%) RGP | Chemical or peroxide | 76.2 | 24 | 24 | NR | 0 |
| Callender et al.16 | 58 normal patients | hydrophilic | Various chemical | 28.1 | 71.9 | 71.9 | 0 | NR |
| Combined analysis of wells and residual solution | ||||||||
| Donzis et al.82 | 100 asymptomatic lens wearers | 62% soft and 38% rigid | chemical, peroxide, and heat | 54 | 46 | 46 | 6.5 | 0 |
| Larkin et al.73 | 102 asymptomatic lens wearers | 67 (65.7%) soft; 35 (34.2%) rigid | 62 (60.8%) chemical; 19 (18.6%) heat; 20 (19.6% peroxide) | 39.2 negligible counts | 42.2 | 42.2 (>106 viable counts/mL) 18.6 (between 10–106 viable counts/mL) | NA | 8.8 (Acanthamoeba sp 6.9) |
| May et al.74 | 40 experienced lens wearers | Rigid | Chlorhexidine based wetting, soaking, and disinfecting solutions | NR | 55 | 55 | NA | NA |
| Wilson et al.76 | 76.2 | 76.2 | Occasional | NA | ||||
| Clark et al.71 | 178 asymptomatic wearers | 132 (74%) soft; 46 (26%) rigid | 75.3% chemical; 21.9% peroxide; 0.6% heat | 46 | 54 | 50 | 0.75 | 3.9 |
| Velasco106 | 126 asymptomatic wearers | Soft | Polyaminopropylbiguanide preserved solution | 19 | 81.0 | 81.0 | 0 | 0 |
NR, not reported; NA, not assessed.