Combining psychophysical and physical attributes is a promising method for the development of novel anterior segment scales; the newly developed scales performed well in a clinical setting.

Despite the generally strong linear associations between the physical characteristics of reference images in each scale, the scales themselves are not inherently accurate and are too different to allow for cross-calibration.

Observers graded from -1 to +1 grade units between and within themselves for a four-point scale, 95% of the time. Although the interobserver and intraobserver repeatability of the K4 and K5M were very similar, a high rate of disagreement in percentage dropout between K4 and K5M images suggests that the two instruments cannot be interchanged. Meibomian gland dropout scores did not correlate significantly with clinical signs. Using a finer scale may be beneficial for detecting change.

On initial presentation, LWE was present in 85% of habitual wearers and found to be independent of age, sex, race, comfort, and refractive error but dependent on habitual SCL type. There were no clinically meaningful differences in LWE between the MPSs and hydrogen peroxide solution for the three lens types studied.

Subjective estimates of redness are based on a combination of chromaticity and vessel-based components. Psychophysical scaling of perceived redness lends itself to being used to cross-calibrate these four clinical scales.