Intraoperative Optical Coherence Tomography-Assisted Descemet Membrane Endothelial Keratoplasty: Toward More Efficient, Safer Surgery.

PURPOSE: To evaluate the clinical value of intraoperative optical coherence tomography (iOCT) and prolonged overpressure in Descemet membrane endothelial keratoplasty for surgical safety, efficiency, and outcome. METHODS: All Descemet membrane endothelial keratoplasties performed by the same surgeon from November 2016 through April 2018 at the University Medical Center Utrecht were included, including 6 months of follow-up. The primary outcome was the prevalence of adverse events, and the secondary outcomes included critical decision-making and surgery time. Surgeries that included prolonged (ca. 12 minutes) overpressurization of the globe were classified as group 1, and those without prolonged overpressurization of the globe were classified as group 2. In all cases, iOCT was used to determine the graft orientation, apposition, and assessment of interface fluid. RESULTS: A total of 38 cases were included for analysis. In groups 1 and 2, 7 (43.6%) and 4 (18.1%) adverse events, respectively, were recorded (P = 0.29). Specifically, in groups 1 and 2, 4 and 3 cases, respectively, required rebubbling because of graft dislocation (P = 0.15). In 43% of surgeries, iOCT proved to be of value for surgical decision-making. Surgery time differed significantly between groups 1 and 2 (P < 0.001) and was the result of a shortened pressurization time in group 2. CONCLUSIONS: iOCT provides a direct assessment of the graft orientation and apposition, allowing the surgeon to refrain from prolonged pressurization of the globe after graft insertion. Optimizing the surgical protocol using iOCT can lead to a significant reduction in surgery time without compromising surgical safety or outcome.

Prospective 3-arm study on pain and epithelial healing after corneal crosslinking.

PURPOSE: To investigate the effect of 3 regimes on pain and wound healing after corneal crosslinking (CXL). SETTING: Tertiary academic referral center, Utrecht, the Netherlands. DESIGN: Prospective cohort study. METHODS: Consecutive progressive keratoconus patients who underwent 9 mW/cm epithelium-off CXL were included. Patients received a bandage contact lens (n = 20), occlusive patch (n = 20), or antibiotic ointment (n = 20) after treatment. Pain scores and quality of life, measured by the McGill Pain Questionnaire and Visual Analogue Scale (VAS), were analyzed. Epithelial healing after 2 days, correlations between pain and psychological factors that influence pain perception (depression anxiety stress score and pain catastrophizing score), and oral pain medication were evaluated. RESULTS: Sixty eyes of 52 patients were analyzed. On average, patients experienced considerable pain after CXL (median VAS score 6.2, range 0 to 10). The postoperative regimen did not significantly affect pain scores, although the antibiotic ointment group reported a higher VAS score (median VAS score 7.2 vs 6.7 and 6.0; P = .57). Occlusive patching showed a trend to quicker resolution of epithelial defects (85% completely healed vs 65% with lenses and 70% with antibiotic ointment; P = .43). Correlations with pain-modulating psychological factors were weak (R < 0.3) and not significant. The use of pain medication corresponded poorly to the prescribed use. CONCLUSION: This study demonstrated clinical equivalence of 3 regimes in combating postoperative pain after routine CXL. Wound healing appeared quicker in the occlusive patch group and therefore might be the best standard of care after CXL. The clinical tradition of using bandage contact lenses should be reevaluated.

The Independent Effect of Various Cross-Linking Treatment Modalities on Treatment Effectiveness in Keratoconus.

PURPOSE: To investigate the 1-year outcomes of using various corneal cross-linking (CXL) techniques for treating keratoconus. METHODS: Setting: This is a prospective longitudinal cohort study performed at a tertiary academic medical center. PATIENT POPULATION: Six hundred seventy eyes of 461 patients with progressive keratoconus who underwent CXL were followed up for 1 year. INTERVENTION: Eight combinations of CXL modalities were assessed, including 2 different CXL techniques (transepithelial or epithelium-off), 7 riboflavin formulations, and 2 ultraviolet-A protocols (conventional 3 mW/cm or accelerated 9 mW/cm). Patients treated using the Dresden protocol were used as the reference group. MAIN OUTCOME MEASURES: Primary outcomes were maximum keratometry and mean keratometry 1 year after treatment. Multivariable linear regression was used which provides ß coefficients (ß). Secondary outcomes were uncorrected and corrected distance visual acuity, manifest refractive spherical equivalent, and corneal thickness 1 year after treatment. RESULTS: Four treatment modalities differed significantly from the reference group regarding both maximum keratometry and mean keratometry: the transepithelial CXL (TE-CXL) group (ß = 1.422; P = 0.001), 1 riboflavin formulation (Meran ß = 1.210; P = 0.02), and both the 9 mW/cm protocols (Vibex Rapid ß = 1.751; P < 0.001 and Collagex ß = 1.170, P < 0.001). Overall, the visual outcome, manifest refractive spherical equivalent, and corneal thickness were similar among the treatment modalities. Infections were rare (1.6% of cases); however, re-treatment was required for 33.3% of cases that underwent TE-CXL. CONCLUSIONS: TE-CXL, the use of Meran riboflavin, and applying the accelerated irradiation protocol appeared to be associated with reduced efficacy regarding controlling keratoconus progression. One-third of cases treated using TE-CXL required re-treatment.

Validation of an Independent Web-Based Tool for Measuring Visual Acuity and Refractive Error (the Manifest versus Online Refractive Evaluation Trial): Prospective Open-Label Noninferiority Clinical Trial.

BACKGROUND: Digital tools provide a unique opportunity to increase access to eye care. We developed a Web-based test that measures visual acuity and both spherical and cylindrical refractive errors. This test is Conformité Européenne marked and available on the Easee website. The purpose of this study was to compare the efficacy of this Web-based tool with traditional subjective manifest refraction in a prospective open-label noninferiority clinical trial. OBJECTIVE: The aim of this study was to evaluate the outcome of a Web-based refraction compared with a manifest refraction (golden standard). METHODS: Healthy volunteers from 18 to 40 years of age, with a refraction error between -6 and +4 diopter (D), were eligible. Each participant performed the Web-based test, and the reference test was performed by an optometrist. An absolute difference in refractive error of <0.5 D was considered noninferior. Reliability was assessed by using an intraclass correlation coefficient (ICC). Both uncorrected and corrected visual acuity were measured. RESULTS: A total of 200 eyes in 100 healthy volunteers were examined. The Web-based assessment of refractive error had excellent correlation with the reference test (ICC=0.92) and was considered noninferior to the reference test. Uncorrected visual acuity was similar with the Web-based test and the reference test (P=.21). Visual acuity was significantly improved using the prescription obtained by using the Web-based tool (P<.01). The Web-based test provided the best results in participants with mild myopia (ie, <3 D), with a mean difference of 0.02 (SD 0.49) D (P=.48) and yielding a corrected visual acuity of >1.0 in 90% (n=77) of participants. CONCLUSIONS: Our results indicate that Web-based eye testing is a valid and safe method for measuring visual acuity and refractive error in healthy eyes, particularly for mild myopia. This tool can be used for screening purposes, and it is an easily accessible alternative to the subjective manifest refraction test. TRIAL REGISTRATION: Clinicaltrials.gov NCT03313921; https://clinicaltrials.gov/ct2/show/NCT03313921.

Clinical Evaluation and Validation of the Dutch Crosslinking for Keratoconus Score.

Importance: Defining keratoconus progression is fundamental in clinical decision making because crosslinking treatments are indicated when the disease is considered progressive. Currently, there is no consensus which parameters should be used to define progression. Objective: To assess and validate a novel clinical scoring system as an easy-to-use assessment tool for crosslinking treatment in patients with keratoconus. Design, Setting, and Participants: Prospective cohort study at 2 academic treatment centers. Patients with keratoconus referred between January 1, 2012, and June 30, 2014, with 2-year follow-up were included. Analysis began March 2017. Interventions: The Dutch Crosslinking for Keratoconus (DUCK) score is based on changes in 5 clinical parameters that are routinely assessed: age, visual acuity, refraction error, keratometry, and subjective patient experience. The DUCK score is derived by scoring 0 to 2 points per item, and cutoffs were determined by clinical experience. We compared the DUCK scores to the conventional 1.0-diopter increase in maximum keratometry criterion, within the last 12 months, in a longitudinal discovery and a validation cohort. Sensitivity analyses and intraitem correlations were performed. Main Outcomes and Measures: Overall treatment rate reduction and the duly withheld treatment rate. Results: A total of 504 eyes of 388 patients were available for analysis on disease progression in the course of 12 and 24 months. Baseline patient characteristics of the discovery cohort and the validation cohort were comparable in terms of age (mean [SD], 26.8 [8.3] years vs 26.3 [9.1]), sex (216 of 332 [65%] vs 123 of 172 [72%] men), and maximum keratometry (mean [SD], 53.5 [7.1] vs 52.7 [6.3]). Adhering to the DUCK score, rather than maximum keratometry, was associated with a reduction in overall treatment rate by 23% (95% CI, 18%-30%), without increasing the risk of disease progression (ie, the rate of progression for both groups was equal; ±0%). The DUCK score appears to better identify eyes that were duly withheld treatment by 35% (95% CI, 22%-49%). Conclusions and Relevance: These results provide validation of the DUCK score as a tool to determine whether a crosslinking treatment might be warranted. Compared with the conventional maximum keratometry criterion of more than 1.0 diopter, the DUCK score may better select patients who might benefit from crosslinking treatment. Potentially, it may prevent unnecessary treatments, reduce exposure to treatment risks, and improve the cost effectiveness of crosslinking.

Comparison of white and blue light assessment of the upper and lower palpebral conjunctiva.

PURPOSE: To compare upper and lower eyelids in terms of palpebral redness, and roughness under two lighting conditions, and assess the extent of association between redness and roughness. METHODS: This was a cross-sectional study conducted at The Netherlands Contact Lens Congress (2016). The palpebral conjunctivae of the right, upper and lower eyelids of 250 subjects were assessed using a slit-lamp biomicroscope. White light was used to assess palpebral redness and roughness. Roughness was also assessed using cobalt blue light and fluorescein. A 5-point grading scale was used to grade the conditions. The average and maximum grades of 5 zones for the upper, and 3 zones for the lower eyelid were used in the non-parametric analysis. RESULTS: A significantly higher grading in palpebral roughness was found using fluorescein with blue light, compared to using white light, for both upper and lower eyelids (p < 0.001). Upper eyelids appeared significantly rougher than lower eyelids with white and blue light (p < 0.001). Correlations between redness and roughness for upper and lower eyelids were low to moderate (p = <0.001). CONCLUSION: Palpebral roughness was scored more highly with blue, than white light, therefore these methods should not be used interchangeably. Also, roughness was more apparent in the upper eyelid, therefore eyelids should be assessed separately. Palpebral redness and roughness should be considered independent variables due to the low to moderate correlation between them. It is therefore recommended to first assess both eyelids first for redness using white light, followed by examination with fluorescein and blue light to assess roughness.

Autorefraction Versus Manifest Refraction in Patients With Keratoconus.

PURPOSE: To compare visual performance using autorefraction and manifest refraction assessments in patients with keratoconus and investigate whether autorefraction measurements lead to suboptimal visual performance. METHODS: Corrected distance visual acuity (CDVA) was measured in 90 eyes of 61 patients with keratoconus with both autorefraction and manifest refraction, in a random order. Maximum keratometry (Kmax), cone location, and wavefront aberration were determined with Scheimpflug tomography. The difference between the autorefraction and manifest refraction outcomes was converted to vectors and a multivariable analysis was performed to identify potential underlying causes of this difference. RESULTS: A significantly better CDVA was achieved with manifest refraction (0.06 vs 0.29 logMAR [20/23 vs 20/38 Snellen], P < .001). After vector analysis, a mean difference of 4.83 diopters was found between autorefraction and manifest refraction. Increased Kmax was strongly and significantly associated with better visual performance of manifest refraction compared to autorefraction (B = 0.496, P = .002). CONCLUSIONS: This study showed that a superior CDVA is achieved with manifest refraction compared to autorefraction in patients with keratoconus. Furthermore, the difference between the two refraction methods increases as the cornea steepens. According to this study, autorefraction is unreliable in patients with keratoconus and should be avoided. [J Refract Surg. 2018;34(1):30-34.].

Performing corneal crosslinking under local anaesthesia in patients with Down syndrome.

PURPOSE: To report on the ability to perform corneal crosslinking (CXL) under local anaesthesia for the treatment of keratoconus in patients with Down syndrome. METHODS: Nine eyes of seven patients with both keratoconus and Down syndrome were scheduled for an epithelium-off CXL procedure under local anaesthesia. Exclusion criteria were a corneal thickness under 400 µm and the presence of corneal scars. A standardized clinical decision tool was used to estimate patient cooperation and the likelihood for a successful procedure under local rather than general anaesthesia. RESULTS: In seven eyes, the CXL was completed successfully. The treatment was aborted in two eyes due to insufficient corneal thickness (<400 µm) prior to ultraviolet-A irradiation, even after employing hypoosmolar riboflavin. No adverse events occurred post-operatively, except for one case of delayed epithelial healing (23 days). CONCLUSIONS: With a proper patient selection, CXL under local anaesthesia can be achieved in patients with Down syndrome.

Higher order optical aberrations and visual acuity in a randomized controlled trial comparing transepithelial versus epithelium-off corneal crosslinking for progressive keratoconus.

PURPOSE: The purpose of this study was to compare the effects of transepithelial crosslinking (trans-CXL) versus epithelium-off crosslinking (epi-off CXL) for progressive keratoconus with respect to the development of higher order aberrations (HOAs) and their effects on visual acuity. MATERIALS AND METHODS: A total of 61 patients were randomized and examined preoperatively and 1, 3, 6, and 12 months postoperatively in an academic referral center. Total corneal HOAs were compared between the two treatment groups using mixed linear modeling. Types of HOAs (coma, trefoil, and spherical aberration) that differed between groups were entered in a multivariable analysis to test their effect on uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA). RESULTS: The epi-off CXL group had more flattening in maximal keratometry compared to the trans-CXL group (P=0.02). UDVA did not differ significantly between the groups (P=0.59); however, CDVA was significantly more improved in the trans-CXL group (P=0.02). Horizontal trefoil improved more in the epi-off group compared to the trans-CXL group (P=0.04), whereas the other HOAs were virtually unchanged in both groups. Differences in changes in HOAs between the two groups had no effect on either UCVA (P=0.76) or CDVA (P=0.96). CONCLUSION: Although HOAs are clinically relevant determinants of vision quality in keratoconus patients, the change in total HOAs post treatment did not differ between the trans-CXL and epi-off CXL groups. Only horizontal trefoil differed significantly post treatment between the trans-CXL and epi-off CXL groups. However, this difference did not independently affect either UDVA or CDVA. Trans-CXL provides no benefit over epi-off CXL regarding visual relevant HOAs.

Predictors for treatment outcomes after corneal crosslinking for keratoconus: a validation study.

Previous research suggested that baseline corrected distance visual acuity (CDVA) and maximum keratometry (Kmax) are the predictors for effectiveness of corneal crosslinking (CXL) for keratoconus. The aim of this study was to validate the previously determined predictors in a new treatment cohort. A prospective cohort of 112 eyes in 90 consecutive patients was used to validate the results of 102 eyes in 79 patients from our previous prospective cohort. All patients were treated using epithelium-off corneal CXL in a tertiary hospital setting. Primary outcomes were changes in CDVA (LogMAR) and Kmax between baseline and 1-year post-treatment. Predictive factors for both outcomes were determined using univariable and multivariable analyses. Lower pretreatment CDVA was found to be the sole independent factor predicting an improvement in CDVA 1 year after CXL (ß coefficient: -0.476, P < 0.01). Kmax flattening is more likely to take place in eyes with preoperative central cones (ß coefficient: 0.655, P < 0.01). These results are consistent with our initial research and indicate high reproducibility in the new cohort. The previously postulated prediction model for postoperative CDVA showed limited predictive value in the validation cohort (R 2 = 0.15). The clinical implication of these results is that patients with lower pretreatment visual acuity are more likely to benefit from CXL (with respect to visual acuity), and patients with more central cones will benefit more in terms of cone flattening. Furthermore, those results can be used to guide customization of the crosslinking treatment.

Higher-order aberrations 1 year after corneal collagen crosslinking for keratoconus and their independent effect on visual acuity.

PURPOSE: To evaluate the effect of corneal collagen crosslinking (CXL) in progressive keratoconus patients on higher-order aberrations (HOAs) and the effect of change in HOAs on visual acuity between baseline and 1 year after CXL. SETTING: Tertiary academic referral center, Utrecht, the Netherlands. DESIGN: Prospective cohort study. METHODS: This study included consecutive keratoconus patients who were treated with epithelium-off CXL and followed for a minimum of 1 year. The following corneal HOAs were measured with Scheimpflug tomography (Pentacam HR type 70900): coma, trefoil, spherical aberration, and total corneal HOAs. A 2-tailed paired-samples t test was used to compare baseline and postoperative aberrations. Multivariable linear regression was applied to assess the independent effects of HOA subtypes on changes in uncorrected (UDVA) and corrected (CDVA) distance visual acuity. RESULTS: Overall, the degree of corneal HOAs in the patient cohort (N = 187) was relatively unchanged after CXL, with a mean change of -1.34% (P = .272). Horizontal coma contributed most to the total amount of HOAs but was virtually unchanged on average. The HOA subtype of spherical aberrations decreased significantly (-15.68%) (P < .001). There was no effect of the change in HOAs on the change in CDVA; however, there was a significant effect of the change in horizontal coma on the change in UDVA (P = .003; B -0.475). CONCLUSIONS: Corneal HOAs in general were relatively unchanged from baseline to 1 year after CXL in eyes with progressive keratoconus. A change in horizontal coma had a strong and independent effect on UDVA. FINANCIAL DISCLOSURE: None of the authors has a financial or proprietary interest in any material or method mentioned.

Corneal Cross-Linking for Pediatric Keratoconus: Long-Term Results.

PURPOSE: To assess the efficacy and safety of cross-linking in pediatric patients with keratoconus and to provide a systematic literature overview regarding this subject. METHODS: In this prospective cohort, 54 eyes of 36 pediatric patients with keratoconus underwent standard epithelium-off cross-linking. Follow-up measurements taken up to 5 years after treatment were compared with baseline values. Logistic regression was used to identify the underlying cause in case of progression despite treatment. Finally, a systematic search was performed in PubMed and Embase, and data were extracted and summarized. RESULTS: At all follow-up visits up to 5 years, maximum keratometry values improved significantly (mean change at 5 years -2.06 diopters (D), P = 0.01); moreover, average keratometry, uncorrected distance visual acuity, and corrected distance visual acuity improved at all follow-up times, though not always to the level of statistical significance. In 12 eyes (22%), keratoconus had progressed by ≥1.0 D by the last follow-up visit, despite corneal cross-linking. Cones that were more decentralized were identified as the underlying cause of disease progression. The systematic search yielded 17 unique articles: 10 articles on epithelium-off cross-linking, 2 on accelerated cross-linking, 2 on transepithelial cross-linking, 1 on both epithelium-off and transepithelial cross-linking, and 2 on transepithelial cross-linking with iontophoresis. CONCLUSIONS: Our long-term follow-up reveals that epithelium-off cross-linking is both apparently safe and effective when used to prevent keratoconus progression in pediatric patients. However, disease progression occurred in 22% of the treated eyes; this progression was attributed to a more decentralized cone location.

Objective and subjective evaluation of the performance of medical contact lenses fitted using a contact lens selection algorithm.

PURPOSE: To evaluate the performance of medical contact lenses (CLs) for a wide range of clinical indications. DESIGN: Prospective cross-sectional study. METHODS: A total of 281 eyes were evaluated in 281 consecutive patients (≥18 years of age; CL use ≥3 months) who visited the contact lens service in a tertiary academic clinic for a scheduled follow-up visit. The main outcome measured were clinical indications for CL wear; CL type; change in corrected distance visual acuity (CDVA) with CL use; CL wearing duration; CL wearing time; subjective performance measured using a visual analog scale (VAS) questionnaire (score range: 0-100); and effectiveness of the lens-selection algorithm. RESULTS: Wearing CLs significantly improved CDVA compared to wearing spectacles (median change: -0.15 logMAR, range: 1.00 to -2.10; P<.001). Daily-wear CLs were worn by 77% of patients for a median of 15h/day (range: 5-18h/day), median 7 days/week (range: 1-7 days/week). High subjective scores were measured, with similar results obtained between the scleral lens and soft lens groups. The medical CL fitting was found to be generally effective (the overall satisfaction rating was ≥70 for 81% of patients). CONCLUSIONS: Fitting CLs based on the lens-selection algorithm yielded positive clinical results, including improved visual acuity, satisfactory wearing time, and high overall subjective performance. Moreover, subjective performance was similar between users of scleral lenses and users of soft lenses. These results underscore the importance of prescribing scleral lenses and the need for tertiary eye clinics to offer patients a variety of CL types.

Scleral lens influence on corneal curvature and pachymetry in keratoconus patients.

OBJECTIVES: To investigate the influence of full scleral lenses on corneal curvature and pachymetry in keratoconus patients. METHODS: In this intervention study, 20 eyes of 14 patients were measured by Scheimpflug imaging (Pentacam HR, Oculus) at two time points: directly and ≥1 week after scleral lens removal. Steep, flat and maximal keratometry (K(steep), K(flat) and K(max)) and optical pachymetry were analyzed. A generalized estimating equation analysis was performed to correct for paired eyes. RESULTS: Directly after scleral lens removal, all three curvature parameters were significantly flatter compared to ≥1 week after scleral lens removal. Average K(steep) was 0.7 diopter (D) lower (P<0.001), average K(flat) was 0.5D lower (P=0.037) and average K(max) was 1.1D lower (P<0.001). Directly after scleral lens removal, average optical pachymetry was ±2.5% higher (P<0.001) compared to ≥1 week after scleral lens removal. CONCLUSIONS: Although scleral lenses do not mechanically touch the cornea, curvature and pachymetry seem to be influenced by scleral lens wear in keratoconus patients. The duration of these changes remain unclear.

Transepithelial versus epithelium-off corneal cross-linking for the treatment of progressive keratoconus: a randomized controlled trial.

PURPOSE: To compare the clinical effects and safety of transepithelial corneal cross-linking (CXL) to epithelium-off (epi-off) CXL in progressive keratoconus. DESIGN: Randomized clinical trial (noninferiority). METHODS: Patients received either transepithelial CXL with Ricrolin TE (n = 35) or epi-off CXL with isotonic riboflavin (n = 26) in 1 academic treatment center, using a simple unrestricted randomization procedure. The main outcome measure was clinical stabilization of keratoconus after 1 year, defined as a maximal keratometry (Kmax) increase <1 diopter (D). RESULTS: Average Kmax was stable at all visits in the transepithelial group, while after epi-off CXL a significant flattening of 1.2-1.5 D was demonstrated from the 3-month follow-up onwards. The trend over time in Kmax flattening was significantly different between the groups (P = .022). Eight eyes (23%) in the transepithelial group showed a Kmax increase of >1 D after 1 year (range 1.3-5.4 D) vs none in the epi-off group (P = .017). There was significant different trend in corrected distance visual acuity (CDVA), with a more favorable outcome in the transepithelial group (P = .023). In the transepithelial group, no complications occurred and in the epi-off group, 4 eyes (15%) developed complications owing to healing problems (sterile infiltrate, herpes keratitis, central haze, and stromal scar). CONCLUSION: This study showed that although transepithelial CXL was a safe procedure without epithelial healing problems, 23% of cases showed a continued keratoconus progression after 1 year. Therefore, at this time, we do not recommend replacing epi-off CXL by transepithelial CXL for treatment of progressive keratoconus.

Scleral lens tolerance after corneal cross-linking for keratoconus.

PURPOSE: Subjective and objective evaluation of scleral lens tolerance and fitting before and after corneal cross-linking (CXL) for progressive keratoconus. METHODS: In this prospective cohort, evaluations were made of 18 unilateral eyes in patients who underwent CXL and had been wearing scleral lenses before the procedure. All the patients gave informed consent; they were able to cooperate with the study, were eligible for CXL, had been wearing well-fitting scleral lenses for at least 3 months, and had no other active ocular disease. Data were collected before and 1 year after CXL. Outcome measures were changes in clinical and subjective scleral lens performance. The following components were studied: scleral lens corrected distance visual acuity, scleral lens specifications, scleral lens fit, wearing time, and subjective measures on visual analogue scale questionnaires (1 to 100 mm). RESULTS: There was no significant change in scleral lens corrected distance visual acuity (p = 0.632). Sixty-one percent of eyes needed a scleral lens fit and/or power change. Wearing time (median, 16 hours per day) and subjective tolerance were found to be stable. CONCLUSIONS: Scleral lens tolerance after CXL appeared to be stable.

Standard and hypoosmolar corneal cross-linking in various pachymetry groups.

PURPOSE: To investigate the influence of corneal thickness on the outcome of corneal cross-linking (CXL) for progressive keratoconus. METHODS: In this cohort study, 72 unilateral eyes were treated by CXL and divided into three groups according to central corneal thickness (CCT) measured by ultrasound pachymetry after 30-minute riboflavin. Group 1 (CCT <400 µm) underwent hypoosmolar CXL; group 2 (CCT 400 to 460 µm) and group 3 (CCT >460 µm) underwent standard CXL. Visual acuity, refraction, topography, ultrasound and optical pachymetry, intraocular pressure, endothelial cell count, and complications were evaluated 1 year post-CXL. RESULTS: Ultrasound CCT after riboflavin instillation decreased significantly in groups 1 and 2 (-57 ± 44 µm and -39 ± 23 µm, respectively) and increased in group 3 (+15 ± 37 µm). One year post-CXL, maximal keratometry decreased significantly in group 2. Keratoconus progression was halted in 92% (group 1), 97% (group 2), and 86% (group 3). Optical pachymetry decreased significantly in all groups. Corrected distance visual acuity improved significantly in groups 1 and 3. No significant difference was found in visual acuity, keratometry, optical pachymetry, or endothelial cell density change between groups. Complication rates were comparable between the groups; there was no significant difference in CXL failure (p = 0.687) or corrected distance visual acuity loss (p = 0.617). CONCLUSIONS: During CXL, corneas with CCT less than or equal to 460 µm seem to dehydrate faster than corneas with CCT greater than 460 µm. Both standard and hypoosmolar CXL are safe and effective treatments, with comparable amounts of stabilization after 1 year.

Corneal cross-linking for treatment of progressive keratoconus in various age groups.

PURPOSE: To compare the effect of corneal cross-linking (CXL) for keratoconus in various age groups and to investigate the influence of the topographic cone location on the outcome of CXL. METHODS: This cohort study included 95 patients (119 eyes) diagnosed as having progressive keratoconus who underwent epithelium-off standard protocol CXL from January 2010 through May 2012. For statistical analysis, patients were divided into three age groups: pediatric patients (< 18 years), adolescent patients (18 to 26 years), and adults (> 26 years). Visual acuity and refraction, topography, intraocular pressure, and endothelial cell counts were recorded preoperatively and postoperatively. RESULTS: Topographic cones were located more centrally in pediatric corneas (0.85 ± 0.66 mm) compared to adolescent corneas (1.49 ± 0.76 mm, P = .002) and adult corneas (1.86 ± 0.99 mm, P < .001). Pediatric corneas flattened 1 year after CXL by a mean of 1.8 diopters (D), compared to 1.1 D in the other age groups. Central cones (0 to 1 mm) were steeper (62.3 ± 8.3 D) before treatment than peripheral cones (3 to 4 mm) (55.9 ± 8.9 D). One year after CXL, corrected distance visual acuity improved in all age groups, with the highest improvement in pediatric eyes (-0.23 ± 0.40 logMAR, P = .044). CONCLUSIONS: Before CXL, cones of pediatric keratoconic corneas were located more centrally than in the two older age groups. After CXL, pediatric corneas showed more corneal flattening and more corrected distance visual acuity improvement. Pediatric CXL was equally safe compared to adolescent and adult CXL.