Daniel A. Godefrooij

Nationwide reduction in the number of corneal transplantations for keratoconus following the implementation of cross-linking.

Keratoconus is characterized by corneal ectasia and irregular astigmatism, which can lead to diminished vision and corneal scarring. Approximately 10–20% of patients with keratoconus eventually require a corneal transplant. Corneal cross‐linking (CXL) is a relatively new treatment that may help prevent the need for corneal transplantation. Here, we investigated whether the introduction of CXL has reduced the number of corneal transplants performed annually.

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.

A multivariate analysis and statistical model for predicting visual acuity and keratometry one year after cross-linking for keratoconus.

PURPOSE To investigate putative prognostic factors for predicting visual acuity and keratometry 1 year following corneal cross-linking (CXL) for treating keratoconus. DESIGN Prospective cohort study. METHODS This study included all consecutively treated keratoconus patients (102 eyes) in 1 academic treatment center, with minimal 1-year follow-up following CXL. Primary treatment outcomes were corrected distance visual acuity (logMAR CDVA) and maximum keratometry (K(max)). Univariable analyses were performed to determine correlations between baseline parameters and follow-up measurements. Correlating factors (P ≤ .20) were then entered into a multivariable linear regression analysis, and a model for predicting CDVA and K(max) was created. RESULTS Atopic constitution, positive family history, and smoking were not independent factors affecting CXL outcomes. Multivariable analysis identified cone eccentricity as a major factor for predicting K(max) outcome (ß coefficient = 0.709, P = .02), whereas age, sex, and baseline keratometry were not independent contributors. Posttreatment visual acuity could be predicted based on pretreatment visual acuity (ß coefficient = -0.621, P < .01, R(2) = 0.45). Specifically, a low visual acuity predicts visual improvement. A prediction model for K(max) did not accurately estimate treatment outcomes (R(2) = 0.15). CONCLUSIONS Our results confirm the role of cone eccentricity with respect to the improvement of corneal curvature following CXL. Visual acuity outcome can be predicted accurately based on pretreatment visual acuity. Age, sex, and K(max) are debated as independent factors for predicting the outcome of treating keratoconus with CXL.

Trends in penetrating and anterior lamellar corneal grafting techniques for keratoconus: a national registry study

Keratoconus is a progressive disorder and one of the primary indications for corneal transplantation. Anterior lamellar keratoplasty offers several advantages over other techniques, including endothelial preservation and longer graft survival. In this study, we examined the recent trend of using lamellar techniques for keratoconus at a national level.

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.

Comment on ‘Cost effectiveness of collagen crosslinking for progressive keratoconus in the UK NHS’

Comment on ‘Cost effectiveness of collagen crosslinking for progressive keratoconus in the UK NHS’

What Are the Costs of Corneal Cross-linking for the Treatment of Progressive Keratoconus?

What Are the Costs of Corneal Cross-linking for the Treatment of Progressive Keratoconus? To the Editor: Although corneal cross-linking (CXL) for keratoconus is increasingly applied, there is limited evidence on the costs of this treatment. One cost-effectiveness study estimated the costs of the total CXL treatment for one simulated patient as £928 (

Autorefraction Versus Manifest Refraction in Patients With Keratoconus

1,392 U.S.).1 In our study, we assessed the costs of CXL in clinical practice, including preoperative eligibility assessments and 1-year follow-up. All consecutive patients referred for keratoconus to our tertiary referral center between September 2012 and July 2013 were included. Surgical treatment was performed according to the Dresden protocol (3 mW/cm2 irradiation for 30 minutes). Inclusion and exclusion criteria were described previously.2 All costs of preoperative consultation, surgical procedure, and postoperative costs during 1 year of follow-up were assessed from the health care perspective, following a microcosting approach in concordance with Dutch guidelines for health economic research.3 Equipment costs were based on purchase value, annual volume, and a 10-year depreciation. Costs of medication were obtained from the Dutch Healthcare Institution.4 All costs were converted to 2015 Euros and an exchange rate of 1.10 to U.S. dollars was applied. A total of 43 patients (86 eyes) were included in this study. Twenty-eight eyes of 20 patients were scheduled for CXL treatment. The mean age of treated patients was 20.2 years and mean uncorrected and corrected visual acuity of treated eyes were 20/100 and 20/29, respectively, with a mean maximum keratometry value of 57.50 diopters. The mean total costs for one eye treated with CXL were €1,754.06 (± 177.23) or

Von Helmholtz's ophthalmometer: historical review and experience with one of the last surviving original devices

1,929.47 (± 194.95). The mean costs of the surgical CXL procedure itself were €719.50 (± 18.82) of

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

791.45 (± 20.70) (Table A, available in the online version of this article). Personnel costs were the main driver, accountable for 88.1% of the total costs. Further cost categories, such as medication, diagnostic procedures, and the ultraviolet-A lamp, were accountable for 4.6%, 4.3%, and 3%, respectively (Figure 1). Although personnel costs are the main expense in the CXL treatment, it should be taken into account that wages can diverge among organizations and countries. In our institution, the surgical procedure is performed by an optometrist, as are parts of the preoperative and postoperative consultation. The investment of medical specialist time is therefore reduced. If all care would be delivered by an ophthalmologist, the costs of the treatment itself would increase by 23.5% and the overall cost by 20.3% (calculations not shown). Accelerated CXL has been shown to produce similar results with shorter ultraviolet-A radiation times and thus shorter surgical procedure times.5 A decreased radiation time from 30 to 5 minutes would save €141.09 or