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Purpose: To evaluate the efficacy of removal and relocation of intracorneal ring segments for improving outcomes in treatment of keratoconus and corneal ectasia., Methods: This is a retrospective case series conducted at a cornea and refractive surgery subspecialty practice setting. Patients with previous insertion of 2 intracorneal ring segments underwent surgical removal and repositioning of segments because of unsatisfactory visual and topographic outcomes. The principal outcomes included uncorrected and corrected visual acuities, manifest refraction, topography-derived maximum keratometry (Kmax), inferior-superior topography power difference (I - S), and higher-order aberration profile derived from wavefront analysis., Results: Three patients are presented in this case series. Uncorrected visual acuity improved in all eyes by an average of 2.75 lines. Corrected visual acuity improved in 2 eyes and remained unchanged in 1 eye. Refractive astigmatism decreased in all patients by an average of 2.50 D. Kmax decreased by an average of 1.43 D. All patients had improvement in the I - S value with a mean decrease of 5.13 D., Conclusions: Topography-guided repositioning and/or replacement of corneal ring segments can result in improved topographic, optical, and visual outcomes in patients in whom the initial result is suboptimal. In these cases, a single segment repositioned beneath the cone resulted in an improved outcome. Analysis of corneal topography can guide the surgeon in treatment planning and can suggest patients in whom such an effort will be rewarded with better results.

Purpose: To assess the effect of preoperative topographic cone location on 1-year outcomes of corneal collagen cross-linking (CXL)., Methods: In this prospective, randomized, controlled clinical trial, 99 eyes (66 keratoconus, 33 ectasia) from 76 patients underwent CXL. Cone location was defined by the coordinates of preoperative maximum keratometry (maximum K) using the anterior sagittal curvature topography map (Pentacam, Oculus Optikgeräte GmbH). Patients were divided into three groups: those with a maximum K located within the central 3-mm (central cone group), 3- to 5-mm (paracentral cone group), and outside the 5-mm (peripheral cone group) optical zones. Topography and visual acuity data were obtained preoperatively and at 1 year., Results: In the combined cohort, maximum K and uncorrected and corrected distance visual acuity significantly improved by -1.60±3.40 diopters (D) (P<.001), -0.08±0.25 logMAR (P=.001), and -0.10±0.18 log-MAR (P<.001), respectively. Comparing cone groups, maximum K decreased by 2.60±4.50 D (P<.001) in the central cone group, 1.10±2.50 D (P=.02) in the paracentral cone group, and 0.40±1.20 D (P=.08) in the peripheral cone group. Differences among groups were statistically significant (P<.001). Uncorrected distance visual acuity improved by -0.07±0.3 logMAR (P=.1) (central cone group), -0.1±0.17 logMAR (P=.004) (paracentral cone group), and -0.1±0.25 logMAR (P=.04) (peripheral cone group). Corrected distance visual acuity improved by -0.14±0.21 logMAR (P<.001) (central cone group), -0.08±0.17 logMAR (P=.01) (paracentral cone group), and -0.08±0.12 logMAR (P=.002) (peripheral cone group). For both UDVA and CDVA outcomes, these differences among groups were not statistically significant., Conclusions: After CXL, more topographic flattening occurs in eyes with centrally located cones and the least flattening effect occurs when the cone is located peripherally. This cone-location effect is found in eyes with both keratoconus and ectasia., (Copyright 2012, SLACK Incorporated.)

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., (Copyright © 2011. Published by Elsevier Inc.)

We describe 2 cases in which evaluation of rigid contact lens fluorescein patterns were used to delineate and characterize topography irregularities. Contact lens analysis confirmed and localized topography findings of an elevated central island in 1 patient and a semicircular pattern in the other patient. To determine a therapeutic strategy to correct topography irregularities after laser refractive surgery, it is critical to document a corneal elevation and delineate its location.

To assess outcomes of corneal crosslinking (CXL) and intracorneal ring segments (ICRS) (Intacs) used adjunctively, and then compare the safety and efficacy of concurrent versus sequential surgery. Cornea and refractive surgery subspecialty practice. Prospective randomized clinical trial. Patients were randomized to one of two groups: ICRS first, immediately followed by CXL during the same session (n = 104), or ICRS followed by CXL 3 months later (n = 94). Outcomes included changes in maximum keratometry (K) and topographic inferior–superior (I–S) difference, maximum flattening of topographic K, and changes in uncorrected (UDVA) and corrected (CDVA) distance visual acuities. These were analyzed in the entire cohort, in the two randomized groups, and in subgroups stratified to ICRS size and placement. Patients were followed for 6 months. The study comprised 198 eyes of 198 patients. Overall, maximum K decreased by an average of 2.5 D, I–S difference improved by 3.9 D, and there was an average maximum flattening of −7.5 D. The UDVA improved by 2.0 logarithm of the minimum angle of resolution lines, on average, and the CDVA improved by 1.1 lines. There was no significant difference between the sequential and concurrent groups in any of the outcomes analyzed. There were 6 clinically significant adverse events. CXL and ICRS can be used adjunctively with substantial improvement in corneal topography, and with no increase in safety concerns over each procedure alone. Sequential and concurrent treatment with ICRS and CXL show equivalent outcomes. Both thicker segment size and single segment placement seem to result in greater topographic improvement. [ABSTRACT FROM AUTHOR]

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 &y& Elsevier]

We present the case of an Alport syndrome patient whose anterior lenticonus was detected by wavefront analysis and Scheimpflug imaging technology. The patient''s lenticular abnormalities were too subtle to be detected by the initial slitlamp examination. Normal corneal topography and elevation maps with high total-eye aberrations pointed to internal optics as the source of aberrations, and predominant negative spherical aberrations suggested anterior lenticonus, a diagnosis confirmed by Scheimpflug images that showed central bulging of the anterior lens surface. Following diagnosis, uneventful phacoemulsification and intraocular lens implantation were performed. We recommend wavefront analysis and Scheimpflug imaging technology as effective tools in the detection of lens disorders, especially those that are too subtle to be observed by other examination methods. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. [Copyright &y& Elsevier]

Purpose: To assess changes in corneal asphericity after laser refractive surgery and mathematically model possible causes of the changes.Setting: Cornea and Laser Eye Institute, Hersh Vision Group, Teaneck, New Jersey, USA.Methods: The corneal topography (EyeSys 2000) of 20 eyes was measured before and after laser in situ keratomileusis, laser-assisted subepithelial keratectomy, and photorefractive keratectomy for myopia. All preoperative and postoperative maps were analyzed using the CTView 4.0, a computer software program for determining quantitative corneal spherical aberration. To define possible mechanisms of asphericity change, 2 mathematical models of corneal ablation were constructed and theoretical postoperative corneal asphericities were determined over a range of corrections from −12.0 to +6.0 diopters. Model 1 assumes homogeneous beam fluence over the ablation zone, and model 2 accounts for a theoretical ablation rate drop off peripherally as a result of the angle of incidence of the laser beam on the cornea. Postoperative clinical corneal spherical aberration was compared to the theoretically predicted asphericity values.Results: After excimer laser procedures, all corneas had positive asphericity within the ablation zone, generally changing from a prolate to an oblate optical contour. The mean asphericity (Q) was −0.17 ± 0.14 (SD) preoperatively and +0.92 ± 0.70 postoperatively. The mean change in spherical aberration was +1.09 ± 0.67 of positive asphericity; the range of asphericity change was +0.40 to +2.73 in the direction of a more oblate corneal profile. A trend toward greater change in asphericity and more oblateness was observed among eyes receiving higher correction. A mathematical model taking into account theoretical beam fluence changes across the ablation zone was highly predictive of the actual postoperative asphericity measurements.Conclusions: The cornea within the ablation zone becomes more oblate after laser refractive surgery. A mathematical model of the change in asphericity, which accounts for the angle of incidence of the laser beam across the ablation area, predicted this change in spherical aberration. If the model is correct, possible changes in laser algorithms, delivering more ablation to the peripheral optical zone, may better retain the native corneal prolate conformation. Moreover, wavefront-guided ablations may have to consider the effects of fluence variability across the optical zone to fully correct spherical as well as other aberrations. [Copyright &y& Elsevier]

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 assess the incidence and motivating determinants of explantation of intracorneal ring segments (ICRS) (Intacs) used for the treatment of keratoconus and corneal ectasia. Setting Cornea and refractive surgery subspecialty practice. Design Retrospective case series. Methods Consecutive cases of ICRS implantation performed to treat keratoconus or corneal ectasia were reviewed to determine the number that were eventually explanted and the motivating factors for explantation. Cases were assigned to 1 of 2 groups: (1) medical complications requiring removal and (2) refractive/topographic problem, with the explantation being elective. The corrected distance visual acuity, uncorrected distance visual acuity, maximum keratometry, and inferior–superior topography power difference before and after ICRS removal were also evaluated. Results The ICRS were explanted from 35 eyes of 31 patients from a total cohort of 572 eyes (6.1%). Of these, 15 ICRS (2.6%) were removed for medical complications and 20 (3.5%) for refractive/topographic considerations. Conclusions A large proportion of ICRS were generally well tolerated on a long-term basis. The incidence of explantation secondary to medical complications was low, with the most frequent complication being infiltration around the segment. Explantation was effective in ameliorating medical complications and can be effective in improving corneal topography and clinical outcomes in some cases. [ABSTRACT FROM AUTHOR]