Roger Steinert | PubMed Health

PubMed2003

Assessment of visual function after corneal transplantation: the quality of life and psychometric assessment after corneal transplantation (Q-PACT) study.

PURPOSE: Many patients with successful corneal grafts have poor vision postoperatively. This study evaluates changes in vision-related quality of life after penetrating keratoplasty (PK). DESIGN: Multicenter prospective cohort study. METHOD: Penetrating keratoplasty candidates from the university-affiliated ophthalmology clinics of four participating centers were enrolled and followed up prospectively. We used the PK-VFQ, a modified version of the Visual Function Index-14, combined with clinical examinations before and at 6 and 12 months after PK. We used multivariate linear regression models to examine predictors of change in PK-VFQ scores. RESULTS: We studied 74 grafts in 71 eyes of 67 patients aged 23 to 91 (mean, 61) years who were followed up for at least 6 months. Indications for surgery included bullous keratopathy (27%), scarring (16%), keratoconus (16%), dystrophies (16%), and regrafts (15%). Median preoperative visual acuity was 20/200 in the graft candidate and 20/30 in the best eye. Median best-corrected postoperative visual acuity in the operated eyes was 20/60 at 6 months. PK-VFQ scores improved at 6 months in 79% by an average of 13.0 points (range, -16.7 to 67.5). Improvement in PK-VFQ scores was associated with younger age (P =.04), poorer preoperative visual acuity in the best eye (P =.001), and postoperative contact lens use (P =.04) but not with postoperative acuity in the grafted eye (P =.49). Postoperatively, 80% of patients were moderately to very satisfied with their vision, and 97% of patients stated they would have the surgery again. CONCLUSIONS: Improvement in visual function is inversely associated with visual acuity in the better-seeing eye but does not correlate with the postoperative acuity in the grafted eye. Although most keratoplasties are done unilaterally in the setting of good visual acuity in the contralateral eye, for the majority of patients visual function improves after PK.

Adult↗

PubMedDate not supplied

The theoretical effect of measured wavefront diameter on estimating peripheral wavefront data.

PURPOSE: To compare the difference between wavefront data measured in the periphery and that calculated from estimations using a smaller measured region. METHODS: A total of 32 eyes were measured using the Alcon LADARWave aberrometer (Alcon Laboratories Inc, Fort Worth, Tex). Aberrations were measured through a dilated pupil to the 6th order at a 6.5-mm diameter. Data were then "clipped" to 5.0, 5.5, and 6.0 mm, and each of these smaller diameter wavefronts was used to estimate the larger diameter wavefront coefficients. The measure of interest was the mean and range of error between the estimated and measured values, and how they varied for the different diameters of known data. RESULTS: The differences in both the mean and range of error were inversely correlated to the diameter of the region of known data. As this region grew smaller, the region estimated grew larger, with resultant larger mean errors. At 5 mm, the estimated zone was an annulus of 0.75-mm width; in this case the estimated higher order aberrations were 60% higher than those measured, with a range of 40% lower to 300% higher. At 5.5 mm and 6.0 mm, these differences were much smaller, but statistically significant. The differences were greatest when significant peripheral aberrations were measured, as can occur with post-laser in situ keratomileusis eyes. CONCLUSION: Basing a treatment on an estimation of the peripheral wavefront may lead to an inaccurate ablation profile. The inaccuracy increases as the size of the measured wavefront decreases relative to the planned ablation zone. The inaccuracy is also greatest when significant peripheral aberrations are present. Refractive surgery systems should only treat optical zones that are smaller than or equal to the diameter of the measured wavefront.

Corneal Topography↗