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Purpose: To quantitate corneal haze and analyze the postoperative time course of corneal haze after transepithelial corneal collagen cross-linking (TECXL) in patients with keratoconus., Methods: Patients underwent TECXL and were randomized into 2 groups. One group received intraoperative riboflavin 0.10% every minute, and the second group received riboflavin 0.10% every 2 minutes during ultraviolet exposure. Scheimpflug densitometry was measured preoperatively, and at 1, 3, 6, and 12 months to assess the postoperative time course. Densitometry measurements were also correlated with visual acuity, pachymetry, and topography outcomes., Results: Fifty-nine eyes of 43 patients with keratoconus were analyzed. Preoperative mean corneal densitometry was 20.45 ± 2.79. Mean densitometry increased at 1 month (22.58 ± 3.79; P < 0.001), did not significantly change between 1 and 3 months (22.64 ± 3.83; P = 0.8), and significantly improved between 3 and 12 months postoperatively (mean6 21.59 ± 3.39; P = 0.002, mean12 20.80 ± 3.27; P = 0.002). There was no difference between preoperative and 1-year densitometry measurements (P = 0.21). There was no significant difference between the 1-minute and 2-minute subgroups. In addition, corneal densitometry at either 3 months or 1 year did not correlate with uncorrected distance visual acuity (P = 0.4), corrected distance visual acuity (P = 0.1), or maximum keratometry (P = 0.5), 1 year after corneal collagen cross-linking (CXL)., Conclusions: After TECXL, corneal haze increased slightly at 1 month, plateaued between 1 and 3 months, and returned to baseline between 3 and 12 months. In general, corneal haze in this study was substantially less than the haze previously reported for the standard cross-linking procedure. CXL-associated corneal haze did not correlate with the postoperative visual or topographic outcomes 1 year after CXL.

Purpose: To investigate the in vivo, corneal, biomechanical changes after corneal collagen cross-linking (CXL) using the Ocular Response Analyzer (ORA) in patients with keratoconus and post-laser in situ keratomileusis (LASIK) ectasia., Methods: Single-center, prospective, randomized, controlled, clinical trial. After CXL (69 eyes, 46 keratoconus and 23 post-LASIK), corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using the ORA and analyzed in a treatment, sham control, and fellow eye control group at baseline and 1, 3, 6, and 12 months., Results: There were no significant changes in CH (change = 0.05 ± 1.5; P = 0.78) or CRF (change = 0.29 ± 1.4; P = 0.1) at 1 year compared with preoperative values. Changes in CH and CRF were not correlated with changes in clinical outcomes of uncorrected visual acuity, best spectacle-corrected visual acuity, and maximum keratometry. There were no significant changes in CH in the sham or fellow eye control groups (P(sham) = 0.7; P(FE) = 0.3) or CRF (P(sham) = 0.6; P(FE) = 0.72)., Conclusions: Despite an increase in CRF at one month, there were no statistically significant changes in CH and CRF measurements 1 year after CXL. Development of other in vivo biomechanical metrics would aid in evaluating the corneal response to CXL.

Purpose: To determine the changes in corneal thickness over time after corneal collagen crosslinking (CXL) for keratoconus and corneal ectasia., Setting: Cornea and refractive surgery subspecialty practice., Design: Prospective randomized controlled clinical trial., Methods: Corneal thickness at the apex, thinnest point, and pupil center were measured using Scheimpflug imaging (Pentacam) at baseline and 1, 3, 6, and 12 months after CXL. The treatment group was compared with both a sham-procedure control group and a fellow-eye control group. Associations with clinical outcomes (uncorrected and corrected distance visual acuities and maximum keratometry) were analyzed., Results: The study comprised 82 eyes, 54 with keratoconus and 28 with ectasia after laser in situ keratomileusis. The mean preoperative thinnest pachymetry was 440.7 μm ± 52.9 (SD). After CXL, the cornea thinned at 1 month (mean change -23.8 ± 28.7 μm; P<.001) and from 1 to 3 months (mean change -7.2 ± 20.1 μm, P=.002), followed by a recovery of the corneal thickness between 3 months and 6 months (mean +20.5 ± 20.4 μm; P<.001). At 1 year, apex and pupil-center thicknesses returned to baseline (P=.11 and P=.06, respectively); however, the thinnest pachymetry remained slightly decreased from baseline to 12 months (mean change -6.6 ± 22.4 μm; P=.01). The recovery of corneal thickness was more rapid in ectasia than in keratoconus. There was no association between the degree of corneal thinning at 3 months and clinical outcomes after CXL., Conclusions: After CXL, the cornea thins and then recovers toward baseline thickness. The cause and implications of corneal thickness changes after CXL remain to be elucidated., Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. Additional disclosure is found in the footnotes., (Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate 1-year outcomes of corneal collagen crosslinking (CXL) for treatment of keratoconus and corneal ectasia., Setting: Cornea and refractive surgery subspecialty practice., Design: Prospective randomized controlled clinical trial., Methods: Collagen crosslinking was performed in eyes with keratoconus or ectasia. The treatment group received standard CXL and the sham control group received riboflavin alone. Principal outcomes included uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, astigmatism, and topography-derived outcomes of maximum and average keratometry (K) value., Results: The UDVA improved significantly from 0.84 logMAR ± 0.34 (SD) (20/137) to 0.77 ± 0.37 logMAR (20/117) (P = .04) and the CDVA, from 0.35 ± 0.24 logMAR (20/45) to 0.23 ± 0.21 logMAR (20/34) (P<.001). Fifteen patients (21.1%) gained and 1 patient lost (1.4%) 2 or more Snellen lines of CDVA. The maximum K value decreased from baseline by 1.7 ± 3.9 diopters (D) (P<.001), 2.0 ± 4.4 D (P = .002), and 1.0 ± 2.5 D (P = .08) in the entire cohort, keratoconus subgroup, and ectasia subgroup, respectively. The maximum K value decreased by 2.0 D or more in 22 patients (31.0%) and increased by 2.0 D or more in 3 patients (4.2%)., Conclusions: Collagen crosslinking was effective in improving UDVA, CDVA, the maximum K value, and the average K value. Keratoconus patients had more improvement in topographic measurements than patients with ectasia. Both CDVA and maximum K value worsened between baseline and 1 month, followed by improvement between 1, 3, and 6 months and stabilization thereafter., Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. Additional disclosure is found in the footnotes., (Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Corneal tissue addition keratoplasty is a novel surgical procedure utilizing preserved allogenic femtosecond laser–shaped corneal tissue inlays to improve corneal topography and vision in patients with keratoconus and ectasia. Purpose: To report results of Corneal Tissue Addition Keratoplasty (CTAK) for keratoconus (KC) and ectasia after laser in situ keratomileusis. Setting: Cornea and refractive surgery practice. Design: Single center, prospective, open label clinical trial. Methods: 21 eyes of 18 patients underwent CTAK. A tissue inlay of preserved corneal tissue was cut to customized specifications with a femtosecond laser and placed in a laser-created channel in the host cornea. Postoperative uncorrected and corrected distance visual acuity (UDVA, CDVA), manifest refraction spherical equivalent (MRSE), topographic mean keratometry (Kmean), maximum keratometry (Kmax), and the point of maximum flattening (Kmaxflat) were measured. Results: Average UDVA improved from 1.21 ± 0.35 logMAR lines (LL) (20/327) to 0.61 ± 0.25 LL (20/82) (P <.001). Average CDVA improved from 0.62 ± 0.33 LL (20/82) to 0.34 ± 0.21 LL (20/43) (P =.002), and average MRSE improved from −6.25 ± 5.45 diopters (D) to −1.61 ± 3.33 D (P =.002). Individually, 20 eyes (95.2%) gained more than 2 lines of UDVA, with 10 eyes (47.6%) gaining more than 6 lines, and no eyes worsening. 12 eyes (57.1%) gained at least 2 lines of CDVA, with 1 eye worsening by more than 2 lines. At 6 months, average Kmean flattened by −8.44 D (P =.002), Kmax flattened by −6.91 D (P =.096), and mean Kmaxflat was −16.03 D. Conclusions: CTAK is a promising procedure to improve visual acuity and topography in patients with KC and ectasia. [ABSTRACT FROM AUTHOR]

Purpose: To assess anterior corneal higher-order aberrations (HOAs) after corneal crosslinking (CXL) and intrastromal corneal ring segments (Intacs) used adjunctively. Setting: Cornea and refractive surgery practice. Design: Prospective, randomized clinical trial. Methods: One hundred fifty-eight eyes of 150 patients were randomized into 2 groups: concurrent, Intacs and CXL during the same session (n = 81), or sequential, Intacs followed by CXL 3 months later (n = 77). Outcomes included changes in total, coma, trefoil, and spherical anterior corneal HOA 6 months after Intacs/CXL. The change in anterior corneal HOAs was correlated with the change in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and topography indices of maximum keratometry (Kmax), maximum flattening keratometry (Kmaxflat), and inferior-superior (I-S) ratio. A subjective visual function questionnaire was also analyzed. Results: UDVA, CDVA, Kmax, I-S, and Kmaxflat all improved 6 months after treatment (UDVA = -0.22 +/- 0.34, P <.001; CDVA = -0.13 +/- 0.24, P <.001; Kmax = -3.1 +/- 3.0D, P <.001; I-S = -4.2 +/- 5.0 diopters [D], P <.001; Kmaxflat = -7.9 +/- 4.0 D, P <.001). Total anterior corneal HOA, vertical coma, and horizontal coma anterior corneal HOAs significantly improved by -1.05 +/- 0.93 [mu]m (P <.001), -1.53 +/- 1.18 [mu]m (P <.001), and -0.35 +/- 0.57 [mu]m (P <.001), respectively. Spherical anterior corneal HOAs increased by 0.24 +/- 0.70 [mu]m (P <.001) at 6 months after Intacs/CXL. The change in trefoil was not statistically significant (P trefoil0 =.06, P trefoil30 =.2). There were no significant differences between the changes in anterior corneal HOAs in the sequential and same-day Intacs/CXL groups. The change in total anterior corneal HOAs was correlated with Kmax, Kmaxflat, and the I-S ratio. There was no correlation between the change in anterior corneal HOAs and the change in visual acuity or visual function survey responses. Conclusions: Total, horizontal coma, and vertical coma anterior corneal HOAs improved after Intacs/CXL. Spherical anterior corneal HOAs increased postoperatively, and there was no change in trefoil. Improvement of anterior corneal HOAs did not correlate with visual acuity improvement or subjective visual satisfaction outcomes. [ABSTRACT FROM AUTHOR]

Purpose: To determine changes in higher-order aberrations (HOAs) after corneal collagen crosslinking (CXL). Setting: Cornea and refractive surgery practice. Design: Prospective randomized controlled clinical trial. Methods: Corneal and ocular HOAs were measured and analyzed using the Pentacam device and Ladarwave aberrometer, respectively, at baseline and 12 months after CXL. Results: Ninety-six eyes (64 keratoconus, 32 ectasia) of 73 patients had CXL. A fellow-eye control group comprised 42 eyes. The mean preoperative total anterior corneal HOAs, total coma, 3rd-order coma, and vertical coma were 4.68 μm ± 2.33 (SD), 4.40 ± 2.32 μm, 4.36 ± 2.30 μm, and 4.04 ± 2.27 μm, respectively. At 1 year, the mean values decreased significantly to 4.27 ± 2.25 μm, 4.01 ± 2.29 μm, 3.96 ± 2.27 μm, and 3.66 ± 2.22 μm, respectively (all P<.001). There were no significant changes in posterior corneal HOAs. The mean preoperative total ocular HOAs, total coma, 3rd-order coma, trefoil, and spherical aberration were 2.80 ± 1.0 μm, 2.60 ± 1.03 μm, 2.57 ± 1.03 μm, 0.98 ± 0.46 μm, and 0.90 ± 0.42 μm, respectively. At 1 year, the mean values decreased significantly to 2.59 ± 1.06 μm, 2.42 ± 1.07 μm, 2.39 ± 1.07 μm, 0.88 ± 0.49 μm, and 0.83 ± 0.38 μm, respectively (all P=.01). After CXL, HOAs were significantly improved compared with the control group. Changes in HOAs were not statistically associated with an improvement in visual acuity or most subjective visual symptoms, however. Conclusion: Corneal and ocular HOAs decreased after CXL, suggesting an improvement in corneal shape. Financial Disclosure: Dr. Hersh is medical monitor for Avedro, Inc. No author has a financial or proprietary interest in any material or method mentioned. [ABSTRACT FROM AUTHOR]