Monolayer cultures are highly sensitive to damage by MPS. In contrast, because stratified human corneal-limbal epithelial cultures are resistant to adverse effects of MPS, it is suggested that models that simulate the stratified structure of the corneal epithelium should be used for in vitro toxicologic testing. Caution should be used when interpreting such studies, because in vitro tests may not be predictive of clinical responses to contact lens products that are known to be safe when used as directed.

Purpose Peripheral refraction and retinal shape may influence refractive development. Peripheral refraction has been shown to have a high degree of variability and can take considerable time to perform. SD OCT and peripheral axial length measures may be more reliable, assuming that the retinal position is more important than the peripheral optics of the lens/cornea. Methods 79 subjects right eyes were imaged for this study (age range: 22 to 34 yr, refractive error: −10 to +5.00.) Thirty deg SD OCT (Spectralis, Heidleberg) images were collected in a radial pattern along with peripheral refraction with an autorefractor (Shin-Nippon Auto-refractor) and peripheral axial length measurements with partial coherence interferometry (PCI) (IOLmaster, Zeiss). Statistics were performed using repeat measures ANOVA in SPSS (IBM), Bland-Altman analyses, and regression. All measures were converted to diopters to allow direct comparison. Results SD OCT showed a retinal shape with an increased curvature for myopes compared to emmetropes/hyperopes. This retinal shape change became significant around 5 deg. The SD OCT analysis for retinal shape provides a resolution of 0.026 dipopters, which is about ten times more accurate than using autorefraction or clinical refractive techniques. Bland-Altman analyses suggest that retinal shape measured by SD OCT and the PCI method were more consistent with one another than either was with AR. Conclusions With more accurate measures of retinal shape using SD OCT, consistent differences between emmetrope/hyperopes and myopes were found nearer to the fovea than previously reported. Retinal shape may be influenced by central refractive error, and not merely peripheral optics. Partial coherence interferometry and SD OCT appear to be more accurate than autorefraction, which may be influenced other factors such as fixation and accommodation. Autorefraction does measure the optics directly, which may be a strength of that method.

Although tests on stratified cells are capable of detecting damage caused by H2O2 in culture medium, residual H2O2 in neutralized ophthalmic formulations had no effect on stratified cells in vitro. These data suggest that H2O2, used appropriately, is a safe disinfectant. Data comparing monolayer and stratified cultures suggest that monolayers are more sensitive to peroxide damage and that the effects of neutralized formulations on stratified cells may better predict the intact corneal epithelial response.