Safety Of Corneal Collagen Cross-linking Research Articles

Safety and Efficacy of Corneal Cross-Linking in Patients Affected by Keratoconus: Long-Term Results.

The present study evaluated the effectiveness and safety of corneal collagen cross-linking (CXL). A total of 886 eyes with progressive keratoconus were enrolled in a retrospective cohort study in a tertiary care university hospital. CXL was performed using a standard epithelium-off Dresden protocol. Visual outcomes, maximum keratometry (Kmax), demarcation line measurements, and complications were recorded. Visual outcomes and keratometric data were analyzed in a subgroup comprising 610 eyes. Uncorrected distance visual acuity (UDVA) improved from 0.49 ± 0.38 LogMAR to 0.47 ± 0.39 LogMAR (p = 0.03, n = 610) three years after the procedure, while corrected distance visual acuity (CDVA) improved from 0.15 ± 0.14 LogMAR to 0.14 ± 0.15 LogMAR (p = 0.007, n = 610). A significant reduction of Kmax from 56.28 ± 6.10 to 54.98 ± 6.19 (p < 0.001, n = 610) was observed three years after CXL. In five eyes (0.82%, 5/610) keratoconus progression continued after CXL. Three eyes were retreated successfully with documented refractive and topographic stability after five years. In the 35 eyes that completed 10 years of follow-up, mean visual acuity and topographic parameters remained stable. In conclusion, CXL is a safe and effective treatment for avoiding keratoconus progression. Long-term data are encouraging, supporting a high safety profile for this procedure.

CORNEAL COLLAGEN CROSSLINKING FOR THE TREATMENT OF MICROBIAL KERATITIS

Collagen cross-linking (CXL) is a new horizon in the treatment of corneal diseases.The corneal stroma is the thickest part of the cornea and is mainly composed of collagen fibrils,charged with stromal maintenance and wound healing. CXL by using UV rays and riboflavin could actas a photo mediator to inactivate pathogens in plasma, platelets, and red blood cells. Riboflavin alsoinduces a change in properties of the collagen and has a stiffening effect on the corneal stroma,which stabilizes it and increases its resistance to enzymatic bacteria degradation avoiding theprogression of corneal melting this study aimed to assess the efficacy and safety of corneal collagencross-linking (CXL) in the management of infectious keratitis.

Efficacy and Safety of Corneal Collagen Crosslinking in Treatment of Progressive Keratoconus with Consideration to the Long-Term Results

Efficacy and Safety of Corneal Collagen Crosslinking in Treatment of Progressive Keratoconus with Consideration to the Long-Term Results

A study to evaluate safety and efficacy of corneal collagen cross-linking with riboflavin in keratoconus patients

Introduction: Keratoconus is a disorder of progressive corneal steepening, resulting in cone shaped protrusion of cornea, corneal thinning, myopia and astigmatism. Objectives: To assess the efficacy and safety of corneal collagen cross-linking with Riboflavin in the management of keratoconus. Materials and Methods: The study was conducted at an eye hospital over a period of 22 months to evaluate utility of corneal collagen cross-linking in treatment of keratoconus. Study group included 10 eyes (6 right and 4 left) of 8 patients (6 males and 2 females) with one year follow-up. Results: Mean age of study population was 24.25 years (SD=5.97; SE=2.11). The mean logMAR UCVA prior to CXL was 0.85 which improved to 0.57 at 12 months. Mean baseline BCVA was 0.464 logMAR, this improved to 0.170 logMAR at 12 months. At baseline a mean SimK astigmatism was 4.99 (SD= 2.56) and this decrease to 4.72 at 12 months. Conclusion: Present study showed improved visual acuity (both UCVA and BSCVA), stable topographic parameters, stable visual acuity and stable endothelial cell counts over a period of 12 months follow up, indicating that corneal collagen cross-linking with riboflavin is a safe and effective treatment option for keratoconus. Keywords: Corneal collagen cross-linking and visual acuity, Keratoconus.

Corneal Collagen Cross-Linking With Photoactivated Chromophore for Infectious Keratitis After Penetrating Keratoplasty.

To evaluate the efficacy and safety of corneal collagen cross-linking with photoactivated chromophore (PACK-CXL) plus medical treatment in comparison with the non-CXL group in the management of graft infections after penetrating keratoplasty. Forty eyes of 40 patients, 18 eyes in the PACK-CXL group and 22 eyes in the non-CXL group, with graft infections were retrospectively reviewed. Patients with microbial keratitis who were resistant to medical treatment for at least 1 week were treated with PACK-CXL in conjunction with medical treatment. The non-CXL group received only medical treatment. The median (interquartile range) size of the infiltrate was 11 (3-12.7) versus 7.5 (3.5-12.7) mm (P = 0.37), the epithelization time was 3 (2.7-5) versus 6 (3-11.2) days (P = 0.06), the complete healing time was 23.5 (17.7-33.5) versus 34 (27.7-41.2) days (P = 0.02), and the best-corrected distance visual acuity was 2.5 (0.5-3) versus 2.0 (0.9-3) logarithm of the minimum angle of resolution (P = 0.79) at presentation and 1 (0.3-3) versus 3 (1-3) logarithm of the minimum angle of resolution (P = 0.19) at the final visit for the PACK-CXL and non-CXL groups, respectively. Resolution of infiltrates was observed in 83.3% and 68.2% of cases in the PACK-CXL and non-CXL groups, respectively (P = 0.28). Graft failure was observed in 5 (27.8%) and 12 (54.5%) patients in the PACK-CXL and non-CXL groups, respectively (P = 0.08). PACK-CXL appears to be a promising adjuvant procedure in the management of resistant graft infections by reducing both the duration required for complete healing and rates of graft failure.

Кросслинкинг роговицы при септических расплавляющих язвах роговицы у собак и кошек

Objective of research. To evaluate the efficacy and safety of corneal collagen cross-linking during melting corneal ulcers in dogs and cats. Describe changes in the properties and structure of the cornea during the entire observation period. Materials and methods. 15 animals were included in the study: 8 dogs and 7 cats that received preliminary treatment for underlying disease, but without positive dynamics. All animals had an infectious-inflammatory process in the cornea with signs of keratomalacia. All animals underwent mechanical diepithelization of cornea with simultaneous surface surgical treatment of pathological tissues. CXL procedure was performed under general anesthesia with preliminary saturation of corneal stroma with riboflavin solution for 30 minutes. Results. All animals showed a decrease in purulent-inflammatory process 3...5 days after CXL. Keratomalacia inhibition was noted on average by 2 ... 3 days after procedure. By 7th day of observation, stabilization of wound process and epithelization of defect were observed in 11 animals. In 4 animals, this process lasted up to 10...12 days. In 13 animals, we observed active corneal vascularization by the 14th day after CXL. In 2 animals, regeneration process was avascular. By 30th day of observation, 13 animals showed complete healing of corneal defect zone with formation of fibrosis and slight vascularization, of which 4 dogs had partial deposition of pigment in defect zone. And 1 cat on 15th day had a perforation of cornea with iris prolapse and subsequent evisceration. Conclusion. This study shows that CXL is effective in animals with infectious keratitis, accompanied by keratomalacia. These results allow us to offer CXL as an alternative to surgical methods of treatment. This method is safe for structures of eye while observing recommended protocols, which was confirmed in our work. However, given small number of patients, further research is required to select optimal combination treatment regimen.

Corneal collagen cross-linking in patients with keratoconus associated with dry eye

Purpose The aim of this study was to assess the safety and efficacy of corneal collagen cross-linking in keratoconus associated with dry eye.Patients and methods This study included 35 eyes of 29 patients diagnosed as having keratoconus associated with moderate dry eye manifestations (as measured by Schirmer 1 test result of 8-4 mm after 5 min). Moreover, 12 keratoconic eyes were also included in this study without any manifestations of dry eye as a control group (as measured by Schirmer 1 test result of ≥15 mm after 5 min). All eyes were subjected to preoperative and postoperative assessments including uncorrected visual acuity, best-corrected visual acuity, pachymetry, simulated keratometry, and corneal topography. The thinnest corneal thickness was at least 400 μm in all eyes. As mentioned before, the degree of preoperative dry eye was assessed using Schirmer 1 test. Epithelium-on cross-linking technique was used. All data were analyzed and recorded.Results The results of ‘epithelium-on’ collagen cross-linking are variable, but its noninvasive nature makes it potentially useful in cases when epithelium debridement is better to be avoided, such as in patients with dry eyes.In our study, there was a remarkable improvement regarding postoperative uncorrected visual acuity and best-corrected visual acuity (one line or more). There was no statistical significant difference between the results among dry eyes and nondry eyes. Average K readings showed a marked reduction reaching more than 2 D. The mean astigmatism showed unremarkable changes. The main central corneal thickness showed marked corneal thinning with reduction in the corneal thickness of ∼50 μm or more in many eyes.Conclusion This study showed no significant difference in efficacy and safety of corneal collagen cross-linking among eyes with keratoconus either associated with dry eye or not.

The Long-term Clinical Outcome after Corneal Collagen Cross-linking in Korean Patients with Progressive Keratoconus

PurposeTo evaluate the long-term clinical effectiveness and safety of corneal collagen cross-linking (CXL) in progressive keratoconus compared with untreated contralateral eyes.MethodsIn this retrospective study, nine eyes of nine patients with progressive keratoconus who received CXL (treatment group) and nine untreated contralateral eyes with keratoconus (control group) were included. All patients were followed for at least 5 years and assessed with best-corrected visual acuity, maximum keratometry, mean keratometry, corneal astigmatism, and corneal thickness. Clinical data were collected preoperatively and at 1, 3, 6, 12, 24, 36, 48, and 60 months, postoperatively.ResultsMean best-corrected visual acuity improved significantly from 0.58 ± 0.37 logarithm of minimum angle of resolution preoperatively to 0.39 ± 0.29 logarithm of minimum angle of resolution at 5 years after corneal CXL (p = 0.012). There was significant flattening of the maximum keratometry and mean keratometry from preoperative values of 63.39 ± 10.89 and 50.87 ± 6.27 diopter (D) to postoperative values of 60.89 ± 11.29 and 49.54 ± 7.23 D, respectively (p = 0.038, 0.021). Corneal astigmatism decreased significantly from 7.20 ± 1.83 D preoperatively to 5.41 ± 1.79 D postoperatively (p = 0.021). The thinnest corneal thickness decreased from 434.00 ± 54.13 to 365.78 ± 71.58 µm during 1 month after treatment, then increased to 402.67 ± 52.55 µm at 5 years, which showed a statistically significant decrease compared to the baseline (p = 0.020). In the untreated contralateral eyes, mean keratometry increased significantly at 2 years compared with the baseline (p = 0.043).ConclusionsCXL seems to be an effective and safe treatment for halting the progression of keratoconus over a long-term follow-up period of up to 5 years in progressive keratoconus.

Corneal collagen cross-linking for keratoconus: Results of 3-year follow-up in Pakistani population

ObjectiveTo assess the effectiveness and safety of corneal collagen cross-linking with riboflavin and ultraviolet A (UV-A) light in arresting the progression of keratoconus. DesignProspective, nonrandomized experimental study. ParticipantsSeventy-one eyes of 66 patients with progressive keratoconus. MethodsCorneal cross-linking was carried out with riboflavin and UV-A light in patients with progressive keratoconus at Al-Shifa Trust Eye Hospital, Pakistan. Standard protocol of cross-linking comprising epithelial debridement, instillation of isotonic riboflavin (0.1%) for 30 minutes, followed by application of UV-A light for 30 minutes with riboflavin was followed. Variables of interest were uncorrected and best corrected visual acuity (BCVA) with spectacles, spherical equivalent refraction, maximum keratometric reading, and central corneal thickness. Three-year results of these variables after cross-linking were analyzed. ResultsMean age of patients was 19.79 ± 3.71 years; 75.8% were male and 24.2% were female. After 3 years, uncorrected visual acuity improved in 31.0% by mean 2.0 ± 1.06 Snellen lines, remained same in 64.8%, and deteriorated in 4.2% by mean 1.33 ± 0.57 lines. BCVA improved in 56.3% by mean 2.37 ± 1.10 Snellen lines, remained the same in 40.8%, and deteriorated in 2.8% by mean 1.50 ± 0.70 lines. Spherical equivalent refraction decreased in 33.8% by mean 2.29 ± 1.48 D, remained stable in 60.6%, and increased in 5.6% by mean 1.43 ± 0.42 D. Maximum keratometric reading showed mean regression of 2.64 ± 1.42 D in 60.6%, stabilization in 35.2%, and mean progression of 2.0 ± 0.17 D in 4.2%. In 95.8% of cases, progression of keratoconus halted. Central corneal thickness was decreased by mean 10.32 ± 21.19 µm. ConclusionsCross-linking is an effective and safe treatment option in halting the progression of keratoconus.

Corneal Collagen Cross-Linking in the Treatment of Progressive Keratoconus: A Randomized Controlled Contralateral Eye Study.

Background:To assess the short-term efficacy and safety of corneal collagen cross-linking (CXL) in preventing the progression of keratoconus (KCN).Materials and Methods:This randomized controlled clinical trial enrolled 26 patients diagnosed with bilateral progressive KCN and were eligible for CXL. In each patient, one eye was randomly selected for treatment, and the contralateral eye served as the control. The patients underwent CXL with riboflavin drops and ultraviolet radiation in the treated eye. One year follow-up data are presented. Postoperatively, patients were assessed for progression of KCN, visual changes, and other findings. The main outcome measures were maximum simulated keratometry (K-max), best spectacle-corrected visual acuity (BSCVA), and average simulated keratometry. P <0.05 was considered as statistically significant.Results:In the treated eyes, the mean K-max values decreased by 0.22 D at 1-year postoperatively and increased by 0.41 D in the control group. This difference was statistically significant (P < 0.001). BSCVA improved slightly (a decrease of 0.13 LogMAR) and decreased slightly in the control group (a 0.01 LogMAR increase). The difference between groups was statistically significant (P = 0.014). There was no decrease in visual acuity attributable to complications of CXL in the treated eyes. At 1-year, the keratometry in 3 (12%) treated eyes increased by more than 0.50 D and were considered cases of failed treatment.Conclusion:Preliminary and 1-year results indicate CXL can halt the progression of KCN in most cases without causing serious complications.

In vivo confocal laser microscopy of morphologic changes after simultaneous LASIK and accelerated collagen crosslinking for myopia: One-year results

To evaluate the safety of corneal collagen crosslinking (CXL) combined with laser in situ keratomileusis (LASIK). Shinagawa LASIK Center, Tokyo, Japan. Case series. Bilateral myopic LASIK patients had unilateral accelerated CXL (KXL System) in the nondominant eye. After LASIK, riboflavin 0.1% was instilled in the residual stromal bed for 60 seconds. After the riboflavin was washed out and the flap placed in its original position, ultraviolet-A light (30 mW/cm(2)) was administered for 60 seconds. The LASIK-CXL eyes and the LASIK-only eyes were compared. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities, manifest refraction spherical equivalent (MRSE), keratometry values, endothelial cell density (ECD), pachymetry, optical coherence tomography (OCT), corneal hysteresis (CH), corneal resistance factor (CRF), keratoconus match index (KMI), and 37 parameters from a dynamic bidirectional applanation device (Ocular Response Analyzer) were analyzed. Morphologic changes were evaluated using confocal microscopy. No significant differences in UDVA, CDVA, MRSE, ECD, dynamic bidirectional applanation readings (eg, CH, CRF, KMI), or 37 additional parameters were found between the 2 groups (P>.05). Increased hyperreflectivity and a demarcation line similar to that seen after CXL were observed in the LASIK-CXL eyes. The demarcation line (mean depth 200.04 μm ± 27.01 [SD]; range 178 to 278 μm) was present in 23 eyes (95.8%); the line was well defined in 2 eyes (8.3%) and faint in 21 eyes (87.5%). Combined LASIK-CXL was safe, causing insignificant corneal biomechanical and morphologic changes similar to those with CXL treatment only. No author has a financial or proprietary interest in any material or method mentioned.

Collagen crosslinking in the management of advanced non-resolving microbial keratitis

AimTo evaluate the efficacy and safety of corneal collagen crosslinking (CXL) in the management of culture proven microbial keratitis.Methods15 eyes of 15 patients of microbial keratitis were included in the...

Collagen Cross-Linking with Photoactivated Riboflavin (PACK-CXL) for the Treatment of Advanced Infectious Keratitis with Corneal Melting

To investigate the efficacy and safety of corneal collagen cross-linking (CXL) with photoactivated riboflavin (photoactivated chromophore for infectious keratitis [PACK]-CXL) in the management of infectious keratitis with corneal melting. Prospective clinical trial. Forty eyes from 40 patients with advanced infectious keratitis and coexisting corneal melting. Twenty-one patients (21 eyes) underwent PACK-CXL treatment in addition to antimicrobial therapy. The control group consisted of 19 patients (19 eyes) who received only antimicrobial therapy. The slit-lamp characteristics of the corneal ulceration, corrected distance visual acuity, duration until healing, and complications were documented in each group. The Mann-Whitney U test was used for statistical analysis. P values less than 0.05 were considered statistically significant. The average time until healing was 39.76 ± 18.22 days in the PACK-CXL group and 46.05 ± 27.44 days in the control group (P = 0.68). After treatment and healing, corrected distance visual acuity was 1.64 ± 0.62 in the PACK-CXL group and 1.67 ± 0.48 in the control group (P = 0.68). The corneal ulceration's width and length was significantly bigger in the PACK-CXL group (P = 0.004 and P = 0.007). Three patients in the control group demonstrated corneal perforation; infection recurred in 1 of them. No serious complications occurred in the PACK-CXL group. Corneal CXL with photoactivated riboflavin did not shorten the time to corneal healing; however, the complication rate was 21% in the control group, whereas there was no incidence of corneal perforation or recurrence of the infection in the PACK-CXL group. These results indicate that PACK-CXL may be an effective adjuvant therapy in the management of severe infectious keratitis associated with corneal melting.

Case of Corneal Perforation as a Complication after Uneventful CXL without Infection

ABSTRACT Purpose To demonstrate that UVA/riboflavin crosslinking (CXL) can cause corneal melting in some unpredictable cases. Materials and methods We will present a case report of 25-year-old male patient referred for emergency keratoplasty which is due to corneal melting and perforation developed after uneventful CXL procedure for the treatment of keratoconus. Results We performed uncomplicated penetrating keratoplasty of the left eye in our hospital. Conclusion CXL is gradually becoming the standard treatment procedure for progressive keratoconus and the only major safety concerns associated with CXL are ocular surface damage and endothelial cell damage. This case has shown, however, that even if CXL seems to have been successful, there is still a risk of adverse outcomes. Our report suggests that further research is necessary regarding the safety of corneal collagen crosslinking in corneas with keratoconus. How to cite this article Demirci G, Ozdamar A. Case of Corneal Perforation as a Complication after Uneventful CXL without Infection. J Kerat Ect Cor Dis 2013;2(3):139-142.

Corneal collagen crosslinking for corneal ectasia of post-LASIK: one-year results.

To evaluate the efficacy and safety of corneal collagen crosslinking (CXL) to prevent the progression of post-laser in situ keratomileusis (LASIK) corneal ectasia. In a prospective, nonrandomized, single-centre study, CXL was performed in 20 eyes of 11 patients who had LASIK for myopic astigmatism and subsequently developed keratectasia.The procedure included instillation of 0.1% riboflavin-20% dextrane solution 30 minutes before UVA irradiation and every 5 minutes for an additional 30 minutes during irradiation. The eyes were evaluated preoperatively and at 1-, 3-, 6-, and 12-month intervals. The complete ophthalmologic examination comprised uncorrected visual acuity, best spectacle-corrected visual acuity, endothelial cell count, ultrasound pachymetry, corneal topography, and in vivo confocal microscopy. CXL appeared to stabilise or partially reverse the progression of post-LASIK corneal ectasia without apparent complication in our cohort. UCVA and BCVA improvements were statistically significant(P<0.05) beyond 12 months after surgery (improvement of 0.07 and 0.13 logMAR at 1 year, respectively). Mean baseline flattest meridian keratometry and mean steepest meridian keratometry reduction (improvement of 2.00 and 1.50 diopters(D), respectively) were statistically significant (P<0.05) at 12 months postoperatively. At 1 year after CXL, mean endothelial cell count did not deteriorate. Mean thinnest cornea pachymetry increased significantly. The results of the study showed a long-term stability of post-LASIK corneal ectasia after crosslinking without relevant side effects. It seems to be a safe and promising procedure to stop the progression of post-LASIK keratectasia, thereby avoiding or delaying keratoplasty.

Corneal collagen crosslinking in progressive keratoconus: Multicenter results from the French National Reference Center for Keratoconus

To report refractive, topographic, and biomechanical outcomes, efficiency, and safety of corneal collagen crosslinking (CXL) 1, 3, 6, and 12 months after treatment. National Reference Centre for Keratoconus, Bordeaux and Toulouse, France. Case series. This retrospective uncontrolled double-center study comprised eyes with progressive keratoconus. Uncorrected distance visual acuity, corrected distance visual acuity (CDVA), corneal pachymetry, endothelial cell count, and corneal hysteresis and corneal resistance factor were evaluated at baseline and at 1, 3, 6, and 12 months. One hundred forty-two eyes were enrolled in the study. At 6 months, the CDVA had stabilized in 53 eyes (48.1%), improved in 36 eyes (32.7%), and decreased in 18 eyes (16.3%). At 12 months, the CDVA had stabilized in 31 eyes (47.6%), improved in 26 eyes (40.0%), and decreased in 8 eyes (12%). At 6 months, keratoconus progression had stopped in 51 eyes (49.03%) and the maximum keratometry (K) value had decreased by more than 1.0 diopter (D) in 37 eyes (35.5%); it continued to progress in 16 eyes (15.3%). At 12 months, keratoconus progression had stopped in 42 eyes (68.8%) and the maximum K value had decreased by more than 2.0 D in 13 eyes (21.3%). The complication rate with loss of vision was 3.5%. Ultraviolet-A light associated with riboflavin CXL is an efficient procedure to stabilize and improve progressive keratoconus. The results reinforce previous studies highlighting the efficacy and safety of the procedure. A large prospective randomized clinical trial is needed.

Corneal melting after collagen cross-linking for keratoconus: a case report

IntroductionCorneal collagen cross-linking is a rather new technique that uses riboflavin and ultraviolet A light for collagen fiber stabilization in keratoconus corneas. Other than reversible side effects, the preliminary results of corneal collagen cross-linking studies suggest that it is a rather safe technique. In this report, we demonstrate a case of corneal melting after corneal collagen cross-linking for keratoconus corneas associated with an acute inflammatory response.Case presentationA 23-year-old Caucasian man with keratoconus cornea stage 1 to 2 underwent uneventful corneal collagen cross-linking treatment according to the Dresden protocol. The next day the patient had intense photophobia, watering and redness of the eye, and his visual acuity was limited to counting fingers. Slit lamp biomicroscopy revealed severe corneal haze accompanied by non-specific endothelial precipitates following an acute inflammatory response. Mild inflammation could be detected in the anterior chamber. Moreover, the re-epithelialization process could barely be detected. His corneal state gradually deteriorated, resulting in descemetocele and finally perforation.ConclusionIn this report, we present a case of a patient with corneal melting after standard corneal collagen cross-linking treatment for keratoconus corneas following an acute inflammatory response. Despite modifying postoperative treatment, elaboration of all apparent associated causes by the treating physicians and undergoing extensive laboratory testing, the patient developed descemetocele, which led to perforation. Our report suggests that further research is necessary regarding the safety of corneal collagen cross-linking in keratoconus corneas.

Safety of Corneal Collagen Cross-linking With UV-A and Riboflavin in Progressive Keratoconus

To assess the possible damage to ocular tissues during treatment of keratoconus with UV-A-riboflavin corneal collagen cross-linking (CXL). Single center, prospective, interventional study. Fourteen eyes of 14 patients aged 28.2 ± 5.9 (mean ± SD) years with progressive keratoconus were treated with UV-A-riboflavin CXL. Corneal endothelium was assessed with the endothelial specular microscope. Central retina was assessed with biomicroscopy fundus examination and with optical coherence tomography using macular thickness protocol. Patients were assessed preoperatively, at week 1, month 1, 3, 6, 9, and 12 after treatment. Comparative preoperative and postoperative results showed stable endothelial cell density (2730 cells/mm, 2793 cells/mm, and 2640 cells/mm, preoperatively, at month 6, and at month 12, respectively) and stable foveal thickness (203, 202, and 205 μm, preoperatively, at month 6, and at month 12, respectively). No morphological abnormalities were noted. UV-A-riboflavin CXL seems to be a safe procedure that does not cause damage to the corneal endothelium and central retina.

Photorefractive Keratectomy Retreatment After LASIK

This prospective, randomized, controlled trial aims to provide evidence in relation to the efficacy and safety of corneal collagen cross-linking (CXL) in the management of progressive keratoconus. Eligible eyes were separately randomized into either treatment or control groups. Collagen crosslinking was performed using 0.1% riboflavin (in 20% dextran T500) and ultraviolet A (UVA) irradiation (370 nm, 3 mW/cm2, 30 min) in accordance with a previously published protocol. At each review, a full clinical ophthalmic examination was performed including endothelial cell count and confocal microscopy. To date, 66 eyes of 49 patients with documented progression of keratoconus have been enrolled and randomized. Interim analysis of treated eyes showed a flattening of the steepest simulated keratometry value (K-max) by an average of 0.74 diopters (D) (P = .004) at 3 months, 0.92 D (P = .002) at 6 months, and 1.45 D (P = .002) at 12 months. A trend toward improvement in best spectacle-corrected visual acuity was also observed. In the control eyes, mean K-max steepened by 0.60 D (P = .041) after 3 months, by 0.60 D (P = .013) after 6 months, and by 1.28 D (P < or = .0001) after 12 months. Best spectacle-corrected visual acuity decreased by logMAR 0.003 (P = .883) over 3 months, 0.056 (P = .092) over 6 months, and 0.12 (P = .036) over 12 months. No statistically significant changes were found for spherical equivalent or endothelial cell density. Preliminary results of this randomized controlled trial suggest a temporary stabilization of all treated eyes after CXL.