Endothelial image quality after descemet stripping with endothelial keratoplasty: a comparison of three microscopy techniques.

PURPOSE: To determine corneal endothelial image quality after descemet stripping with endothelial keratoplasty (DSEK) as recorded by three different microscopy techniques: noncontact specular microscopy, noncontact confocal microscopy, and contact confocal microscopy. METHODS: The corneal endothelium of 52 eyes after DSEK and 20 normal eyes was photographed by the three microscopy techniques during a single encounter. Image quality was graded by two masked observers according to the proportion of countable contiguous cells visible in the image; disagreements in grading were adjudicated by a third observer. Endothelial cell density was compared among the three techniques. RESULTS: After DSEK, image quality was better with contact confocal microscopy than with noncontact confocal microscopy (P = 0.01) and better with noncontact confocal microscopy than with noncontact specular microscopy (P < 0.001). With noncontact specular microscopy, 42% of images after DSEK were uncountable. In normal corneas, all images were countable, and although image quality was better with contact confocal microscopy than with noncontact confocal (P = 0.03) and noncontact specular (P < 0.001) microscopy, the difference was not clinically important. For countable images, the mean differences in endothelial cell density between microscopy methods were close to zero after DSEK and in normal corneas. CONCLUSIONS: Confocal optics enable better image quality of the corneal endothelium in corneas with high backscatter, such as those after DSEK. When images were countable, there was a good agreement for endothelial cell density measured by the three microscopy techniques.

Retinal point-spread function after corneal transplantation for Fuchs' dystrophy.

PURPOSE: To determine the effect of corneal transplantation for Fuchs' dystrophy and of recipient age on the large- and small-angle domains of the retinal point-spread function. METHODS: Retinal stray light (large-angle domain) and the full-width-at-half-maximum intensity of the point-spread function (50% width, small-angle domain) were measured in 40 pseudophakic eyes after keratoplasty (Descemet stripping with endothelial keratoplasty [DSEK], 30 eyes; penetrating keratoplasty [PK], 10 eyes) for Fuchs' dystrophy and in 30 otherwise normal pseudophakic eyes. Correlations were assessed between the optical variables, high-contrast visual acuity (HCVA), and recipient age, and variables were compared between groups by using generalized estimating equation models. RESULTS: The 50% width was higher in pseudophakic eyes after DSEK or PK compared with otherwise normal pseudophakic eyes (P < 0.001) but did not differ between DSEK and PK (P = 0.36). After DSEK, HCVA correlated with the 50% width (r = 0.48, P < 0.001, n = 25) and stray light (r = 0.44, P = 0.01, n = 30), whereas after PK, HCVA correlated with the 50% width (r = 0.77, P = 0.003, n = 10) but not with stray light (r = 0.01, P = 0.98, n = 8). Stray light correlated with recipient age after DSEK (r = 0.67, P < 0.001, n = 30), but not after PK (r = 0.35, P = 0.39, n = 8,), and not with age of otherwise normal pseudophakic eyes (r = 0.32, P = 0.18, n = 29). CONCLUSIONS: The degradation of the small-angle domain of the point-spread function after DSEK suggests that aberrations contribute to decreased visual acuity after DSEK. The poorer optical properties of the eye with older recipient age after DSEK can be attributed to the retained host cornea.

Subbasal nerve density and corneal sensitivity after laser in situ keratomileusis: femtosecond laser vs mechanical microkeratome.

OBJECTIVE: To compare changes in subbasal nerve density and corneal sensitivity after laser in situ keratomileusis (LASIK) with the flap created by a femtosecond laser (bladeless) vs a mechanical microkeratome. DESIGN: In a randomized paired-eye study, 21 patients received myopic LASIK with the flap created by a femtosecond laser in one eye and by a mechanical microkeratome in the fellow eye. Eyes were examined before and at 1, 3, 6, 12, and 36 months after LASIK. Central subbasal nerve density was measured by using confocal microscopy. Corneal mechanical sensitivity was measured by using a gas esthesiometer and was expressed as the ratio of mechanical threshold in eyes that received LASIK to mechanical threshold in concurrent control eyes. RESULTS: Subbasal nerve density and corneal sensitivity did not differ between methods of flap creation at any examination. Mean (SD) nerve density was decreased at 1 month (bladeless, 974 [2453] µm/mm(2); microkeratome, 1308 [2881] µm/mm(2)) compared with the preoperative examination (bladeless, 10,883 [5083] µm/mm(2), P < .001; microkeratome, 12,464 [6683] µm/mm(2), P < .001) and remained decreased through 12 months (P < .001). Mechanical threshold ratios did not differ from that at the preoperative examination through 36 months for either LASIK treatment; when all LASIK eyes were combined, the mechanical threshold ratio was transiently higher (decreased sensitivity) at 1 month (1.29 [0.85]) compared with the preoperative examination (0.89 [0.73], P = .05). CONCLUSIONS: The planar configuration of the femtosecond laser flaps is not associated with faster reinnervation compared with the microkeratome flaps. The prolonged decrease in subbasal nerve density after LASIK is not accompanied by a prolonged decrease in corneal sensitivity. TRIAL REGISTRATION: clinicaltrials.gov Identifier NCT00350246.

Host and graft thickness after Descemet stripping endothelial keratoplasty for Fuchs endothelial dystrophy.

PURPOSE: To determine relationships between vision, forward scatter, and total corneal and graft thicknesses after Descemet stripping endothelial keratoplasty (DSEK). DESIGN: Prospective, cohort study. METHODS: Forty-four eyes with Fuchs endothelial dystrophy were examined before and at 1, 3, 6, and 12 months after DSEK; all eyes were pseudophakic after surgery. Central total corneal and graft thicknesses were measured using confocal microscopy. Best-corrected high-contrast visual acuity (BCVA) was measured using the electronic Early Treatment Diabetic Retinopathy Study protocol, and forward light scatter was measured using a straylight meter. RESULTS: Total corneal thickness was 610 ± 50 µm (mean ± standard deviation) before DSEK, increased to 680 ± 74 µm by 1 month after DSEK (P < .001), and stabilized at 660 ± 68 µm by 3 months after DSEK (P = .03 vs 1 month). Graft thickness was 170 ± 57 µm at 1 month, decreased to 157 ± 49 µm by 3 months (P = .004), and then remained stable through 12 months (156 ± 51 µm; P = .99 vs 3 months). BCVA was 0.44 ± 0.21 logarithm of the minimal angle of resolution (logMAR) units (Snellen equivalent, 20/55) before DSEK, improved to 0.26 ± 0.20 logMAR units (Snellen equivalent, 20/36) by 3 months (P < .001), and improved to 0.16 ± 0.16 logMAR units (Snellen equivalent, 20/29) at 12 months (P < .001 vs 3 months). BCVA and forward light scatter did not correlate with corneal or graft thickness after DSEK. CONCLUSIONS: Stromal edema resolves by 3 months after DSEK for Fuchs dystrophy, whereas visual acuity continues to improve through 12 months. Thicker corneas and grafts are not associated with worse visual acuity or increased forward scatter.

Corneal subbasal nerve density: a comparison of two confocal microscopes.

PURPOSE: To compare subbasal nerve densities estimated from images recorded by the tandem scanning and the ConfoScan 4 confocal microscopes. METHODS: Confocal microscopy was used to estimate subbasal nerve density in 62 corneas of 40 subjects (18 corneas of 18 normal subjects and 44 corneas of 22 patients between 1 and 12 months after LASIK). At each examination, corneas were scanned first by using tandem scanning and then by using a ConfoScan 4 confocal microscope. Subbasal nerves from 2 to 4 scans per cornea were traced by using a semi-automated nerve analysis program. Nerve density was expressed as total nerve length divided by the sample area (microm/mm2). Differences in nerve density between instruments were examined by using paired tests. RESULTS: In normal corneas, subbasal nerve density was 10,658 +/- 5,581 microm/mm2 (mean +/- SD) with the ConfoScan 4 and 5,534 +/- 1,850 microm/mm2 with the tandem scanning microscope (P<0.0001). One to 12 months after LASIK, mean subbasal nerve density was 2,477 +/- 3,514 microm/mm2 estimated with the ConfoScan 4 and 844 +/- 983 microm/mm2 estimated with the tandem scanning (P =0.0003). Estimates of nerve density were correlated between instruments (r = 0.71, P<0.0001), although the mean difference between instruments was 2,308 +/- 3,885 microm/mm2 (P<0.0001). CONCLUSIONS: Mean subbasal nerve density estimated with the ConfoScan 4 was 2 to 3 times higher than density estimated with the tandem scanning confocal microscope. These differences must be considered when comparing subbasal nerve densities between studies that use different confocal microscopes.

Human glycemic response and phenolic content of unsweetened cranberry juice.

This cross-sectional study determined the phenolic composition of an over-the-counter cranberry juice (CBJ) with high-performance liquid chromatography and examined the effects of low- and normal-calorie CBJ formulations on the postprandial glycemic response in healthy humans. The CBJ used in this study contained seven phenolic acids, with 3- and 5-caffeoylquinic acid being the primary components, and 15 flavonol glycosides, with myricetin-3-galactoside and quercetin-3-galactoside being the most prevalent. CBJ proanthocyanidins consisted of three different tetramers and a heptamer, which were confirmed with matrix-assisted laser desorption ionization-time of flight-mass spectrometry analysis. Participants received one of the following six treatments: nothing (no water/beverage), water (480 mL), unsweetened low-calorie CBJ (38 Cal/480 mL), normal-calorie CBJ (280 Cal/480 mL), isocaloric normal calorie (high fructose corn syrup [HFCS]), or isocaloric low-calorie beverages. No significant differences in postprandial blood glucose or insulin were observed in the groups receiving nothing, water, or low-calorie treatments. In contrast, the ingestion of normal-calorie CBJ and normal-calorie control beverage resulted in significantly higher blood glucose concentrations 30 minutes postprandially, although the differences were no longer significant after 180 minutes. Plasma insulin of normal-calorie CBJ and control (HFCS) recipients was significantly higher 60 minutes postprandially, but not significantly different 120 minutes postprandially. CBJ ingestion did not affect heart rate or blood pressure. This study suggests that the consumption of a low-calorie CBJ rich in previously uncharacterized trimer and heptamer proanthocyanidins is associated with a favorable glycemic response and may be beneficial for persons with impaired glucose tolerance.