In this study, we confirmed the relationship between stray light and recipient age in pseudophakic eyes after DSEK for Fuchs' dystrophy,
3 whereas no such relationship was evident after PK, nor between stray light and age of otherwise normal pseudophakic eyes. Similarly, larger series have found weak, if any, correlations between stray light and age in pseudophakic eyes.
10,22 The age-dependence of stray light after DSEK suggests that the age of the host cornea affects the postoperative optical properties of the eye, and we have hypothesized that increased forward scatter in older recipients might be a consequence of more advanced Fuchs' dystrophy before DSEK, or to slower repair of the host ultrastructural changes in older corneas after DSEK.
3 The exact nature of the ultrastructural changes in host corneas with Fuchs' dystrophy that are responsible for optical degradation, and whether they are reversible with time, are unknown, but could include subepithelial fibrosis,
23 extracellular matrix alterations,
24 or anterior keratocyte depletion.
25 Of interest is that visual acuity after DSEK is worse in older than in younger recipients for eyes without retinal or other causes of decreased vision,
3,26 further suggesting increased optical degradation of older host corneas. Nevertheless, forward scatter does not affect visual acuity except in extreme cases, and in this study, we were unable to detect relationships between the established parameter of the small-angle domain (50% width), which is related to visual acuity, and recipient age.
Most of the subjects in this study were elderly, and one might argue that the relationship between stray light and age after DSEK might be attributed to age-related ability to successfully perform the test. However, this is unlikely to be the case because stray light measurement by the psychophysical technique is almost identical with that by optical techniques,
6 and the reliability indices exclude tests with large variability
10 ; in addition, subjects with otherwise normal pseudophakic eyes were of similar age.