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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 evaluate changes in corneal topography indices after corneal collagen crosslinking (CXL) in patients with keratoconus and corneal ectasia and analyze associations of these changes with visual acuity. Setting: Cornea and refractive surgery subspecialty practice. Design: Prospective randomized controlled clinical trial. Methods: Corneal collagen crosslinking was performed in eyes with keratoconus or ectasia. Quantitative descriptors of corneal topography were measured with the Pentacam topographer and included 7 indices: index of surface variance, index of vertical asymmetry, keratoconus index, central keratoconus index, minimum radius of curvature, index of height asymmetry, and index of height decentration. Follow-up was 1 year. Results: The study comprised 71 eyes, 49 with keratoconus and 22 with post-LASIK ectasia. In the entire patient cohort, there were significant improvements in the index of surface variance, index of vertical asymmetry, keratoconus index, and minimum radius of curvature at 1 year compared with baseline (all P<.001). There were no significant differences between the keratoconus and ectasia subgroups. Improvements in postoperative indices were not correlated with changes in corrected or uncorrected distance visual acuity. Conclusions: There were improvements in 4 of 7 topography indices 1 year after CXL, suggesting an overall improvement in corneal shape. However, no significant correlation was found between the changes in individual topography indices and changes in visual acuity after CXL. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. Additional disclosure is found in the footnotes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Purpose: To determine the natural history of collagen crosslinking (CXL)–associated corneal haze measured by Scheimpflug imagery and slitlamp biomicroscopy in patients with keratoconus or ectasia after laser in situ keratomileusis. Setting: Cornea and refractive surgery subpecialty practice, United States. Design: Prospective randomized controlled clinical trial. Methods: The treatment group received ultraviolet-A/riboflavin CXL therapy. The control group received riboflavin alone without epithelial debridement. To objectively measure CXL-associated corneal haze, corneal densitometry using Scheimpflug imagery was measured and the changes in haze were analyzed over time. A similar analysis was performed using clinician-determined slitlamp haze. Correlation of CXL-associated corneal haze with postoperative outcomes was analyzed. Results: The mean preoperative corneal densitometry was 14.9 ± 1.93 (SD) (Pentacam Scheimpflug densitometry units). Densitometry peaked at 1 month (mean 23.4 ± 4.40; P<.001), with little change at 3 months (mean 22.4 ± 4.79; P = .06) and decreased between 3 months and 6 months (19.4 ± 4.48; P<.001) and between 6 months and 12 months. By 12 months, densitometry had not completely returned to baseline in the entire cohort (mean 17.0 ± 3.82; P<.001) and the keratoconus subgroup; however, it returned to baseline in the ectasia group (16.1 ± 2.41; P = .15). The postoperative course of slitlamp haze was similar to objective densitometry measurements. Increased haze, measured by densitometry, did not correlate with postoperative clinical outcomes. Conclusions: The time course of corneal haze after CXL was objectively quantified; it was greatest at 1 month, plateaued at 3 months, and was significantly decreased between 3 months and 12 months. Changes in haze did not correlate with postoperative clinical outcomes. Financial Disclosure: Drs. Greenstein and Fry and Ms. Bhatt have no financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes. [Copyright &y& Elsevier]