Corneal Cross-linking Research Articles

Long-Term Outcomes After Corneal Cross-linking for Progressive Keratoconus and Corneal Ectasia: A 10-Year Follow-Up of the Pivotal Study.

To report on the topographic and visual outcomes 10 years after corneal cross-linking in patients with progressive keratoconus and corneal ectasia after refractive surgery. Cross-sectional cohort study of an original, prospective, randomized, clinical trial. Patients treated in a single center cornea and refractive surgery practice as part of the U.S. pivotal trials, which led to the Food and Drug Administration approval of corneal cross-linking, were recruited for a 10-year follow-up examination. LogMar lines (LL) of uncorrected visual acuity (UCVA) and best spectacle--corrected visual acuity (BSCVA), maximum keratometry, and thinnest pachymetry were evaluated. In addition, the Belin ABCD progression display was used to determine progression (95% confidence interval) of the anterior curvature, posterior curvature, and corneal thickness of each individual eye included. Nineteen eyes of 13 patients treated with standard cross-linking returned for a 10-year follow-up examination. Mean maximum keratometry changed from 58.2±12.0 diopters (D) to 58.3±10.1 D, thinnest pachymetry changed from 440.6±51.6 µm to 442.3±54.4 μm, UCVA changed from 0.79±0.42 LL to 0.86±0.46 LL, and BSCVA changed from 0.38±0.26 LL to 0.33±0.34 LL, 10 years after cross-linking. Individually, 68.5% of the entire cohort, 81.8% of keratoconus eyes, and 50% of eyes with corneal ectasia remained topographically stable 10 years after standard cross-linking. In the entire cohort, visual acuity and topography remained stable 10 years after cross-linking. Over the long-term, eyes with keratoconus seem to be more stable than those with corneal ectasia.

Intrastromal Corneal Ring Segment Implantation Followed by Simultaneous Topography-Guided Photorefractive Keratectomy and Corneal Cross-Linking for Contact Lens-Intolerant Keratoconus.

This study aimed to evaluate the efficacy and safety of Keraring implantation followed by simultaneous topography-guided photorefractive keratectomy (TGPRK) and corneal cross-linking (CXL) in the management of keratoconus. This is a single-center, private practice, retrospective review. Patients with keratoconus who were intolerant to contact lens wear underwent implantation of the Keraring, followed by TGPRK with CXL from 2 to 36 months after implantation. Main outcome measures were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction (cylinder and spherical equivalent), keratometry (steep, maximum, and central), and central corneal thickness (CCT). Patients were followed up for 3 to 60 months postoperatively. Fifty-seven eyes from 45 patients were included. The mean time between Keraring and TGPRK/CXL was 6.0 ± 6.0 months. Patients were followed up for a mean of 28.6 ± 20.1 months after Keraring insertion. At 12-month follow-up, there was a statistically significant improvement in mean UDVA (0.94 ± 0.49-0.35 ± 0.23, P < 0.01), CDVA (0.39 ± 0.26-0.17 ± 0.15, P < 0.01), cylinder (-4.97 ± 2.68 to -1.74 ± 1.25, P < 0.01), steep keratometry (51.25 ± 3.37-45.03 ± 2.27, P < 0.01), central keratometry (52.59 ± 4.98-46.99 ± 3.53, P < 0.01), and maximum keratometry (58.78 ± 4.22-50.76 ± 3.42, P < 0.01). These results were sustained at 48-month follow-up. CCT decreased at 12 months after TGPRK (461.84 ± 27.46-418.94 ± 45.62, P < 0.01) and remained stable at 60 months. Postoperatively, 2 eyes (3.51%) had corneal haze, resulting in decrease in CDVA; 1 was treated successfully with repeat PRK; and 1 patient (1.75%) had wound melt due to partial Keraring extrusion, which settled with repositioning. Keraring implantation followed by simultaneous TGPRK and CXL appears to be effective in the long term in improving UDVA, CDVA, cylinder, CCT, and keratometry in patients with keratoconus who are intolerant to contact lenses.

A Case Series of Infectious Keratitis After Corneal Cross-linking.

To present the 7-year experience of a tertiary eye hospital while exploring possible risk factors and incidence of infectious keratitis in patients undergoing standard corneal cross-linking (CXL). This retrospective cohort study included patients with progressive keratoconus undergoing standard CXL in the Farabi Eye Hospital and all other patients who had undergone CXL in other facilities and were diagnosed as having infectious keratitis in the 7-year period of the study. Among the total of 4,863 eyes that underwent CXL, 6 eyes developed infectious keratitis, yielding an incidence rate of 0.12%. Additionally, 13 eyes from 10 patients with a CXL history in other facilities who developed infectious keratitis were included. The mean age was 23.75 years, and 75% of patients were men and 25% were women. Gram-positive bacteria and Staphylococcus aureus were the most prevalent pathogens. Meibomian gland dysfunction, dry eye disease, or blepharitis were present in 12 patients. Medical treatment did not arrest the disease progress in 5 patients, which eventually required cases to undergo keratoplasty. This study supports the need for proper patient selection by using a comprehensive medical history. It also highlights the imperative role of rigorous patient education and follow-up, particularly in the first postoperative week. Finally, the study emphasizes aggressive early therapy for patients with suspicious findings. [J Refract Surg. 2023;39(8):564-572.].

Development of interface haze after femtosecond laser-assisted in situ keratomileusis with accelerated corneal crosslinking: a case series.

Femtosecond laser-assisted in situ keratomileusis (FS-LASIK) with accelerated corneal crosslinking (FS-LASIK Xtra) is a recent procedure to achieve safer corneal ablation in myopic patients with borderline corneal thickness. Despite its well-accepted effectiveness, the development of remarkable interface haze is a potential concern but has rarely been reported and discussed. We report for the first time a case series of 11 eyes of 7 patients who developed typical interface haze 1-3months after FS-LASIK Xtra for the correction of myopia with astigmatism, with intensity grades ranging from 0.5 + to 3 + at the time of onset. The preclinical spherical diopters of the 7 patients ranged from - 2.25 D to - 9.25 D and cylindrical diopters ranged from - 0.25 D to - 2.50 D. The haze tended to be self-limiting, and topical anti-inflammatory therapy was given to moderate and severe cases, who responded well to treatment. The development of clinically significant interface haze is a relatively rare complication after FS-LASIK Xtra but tends to have a higher incidence and intensity compared to conventional stromal surgery such as FS-LASIK. Timely treatment and close follow-up are essential to patients undertaking FS-LASIK Xtra.

Corneal Collagen Cross-Linking for Progressive Keratoconus in Pediatric Patients: Up to 14 Years of Follow-up

To assess the long-term outcomes of corneal collagen cross-linking according to the Dresden protocol (S-CXL) in progressive pediatric keratoconus (KC). Retrospective, single-center noncomparative interventional study. Patients aged <18 years who underwent S-CXL from June 2007 to January 2011 in Humanitas Clinical and Research Center, Rozzano, Milan, Italy, and completed at least 10 years of follow-up were included. Corrected distance visual acuity (CDVA), refraction, and tomography were evaluated at baseline and ≥10 years after S-CXL. Meeting 2 of the following 3 criteria indicated reprogression: progression above 95% CI for post-CXL population of A or B values or a decrease in minimal thickness C evaluated with the ABCD display. Thirty-eight eyes of 24 patients fulfilled inclusion criteria. At a mean of 11.6 years postoperation (maximum 14 years), the CDVA improved significantly (from 0.703 ± 0.33 decimal fraction to 0.887 ± 0.2, P < .001). Similarly, the A value significantly improved from 2.550 ± 1.7 to 1.627 ± 1.68 (P=.019). Thirteen eyes (34%) showed significant postoperative progression in 2 of the 3 parameters A, B, and C. Of these, only 3 eyes (7.9%) of 3 patients showed a statistically significant change in the A value. S-CXL proved to be a safe treatment for progressive KC in pediatric patients with an anterior curvature progression rate of up to 7.9% at ≥10 years of follow-up.

The efficacy of 2 different phakic intraocular lens implant in keratoconus as an isolated procedure or combined with collagen crosslinking and intra-stromal corneal ring segments: a systematic review and meta-analysis.

To compare the efficacy of phakic intra-ocular lenses in isolation or in combination with corneal crosslinking (CXL) and/or intra-stromal corneal ring segments (ICRS) in keratoconus. Data extracted from the publications meeting the selection. The outcome parameters included mean pre- and post-operative uncorrected distance visual acuity, corrected distance visual acuity (CDVA), sphere and cylinder of refraction and complications. Available data analyzed with Cochrane Review Manager. A total of 23 studies including 464 eyes were included. All the parameters showed significant improvement in all subgroups other than CDVA in ACPIOL + CXL subgroup and cylinder in PIOL + CXL subgroups. There was not a significant difference between PCPIOL and ACPIOL in the outcomes, exception was more improvement of CDVA in "ACPIOL only" than" PCPIOL only" subgroup. Both PCPIOLs and ACPIOLs are comparably safe and efficient options in management of KCN and their efficacy significantly improves when combined with CXL/ICRS.

Study Of Macular Function and Morphology After Transepithelial Accelerated Corneal Collagen Cross-linking in Progressive Keratoconus

Objective The aim of this work is to evaluate the effect of transepithelial accelerated cross-linking (Epi-on CXL) on the macular function and morphology in progressive keratoconus. Patients and Methods The study included 25 patients with progressive keratoconus with age ranged between 18 and 32 years. Epi-On Accelerated CXL was done for all cases. Evaluation was performed 2 and 6 weeks postoperatively after transepithelial (Epi-on) accelerated CXL by Optical coherence tomography (OCT) and multifocal electroretinography (mf-ERG). Results The central foveal thickness (CFT) decreased from 165.1 ± 21.5 µm to 163.4 ± 24.2 µm 2 weeks postoperatively to 164.8 ± 23.9 µm 6 weeks postoperatively, with no statistically significant difference. The preoperative retinal response density (RRD) decreased in macular ring 1 (foveal area of 2.8 degrees) from 179.5 ± 52.1 nV/deg2 preoperatively to 134.7 ± 43.2 nV/deg2 and 146.7 ± 41.6 nV/deg2 in 2 and 6 weeks, respectively postoperatively with statistically significant difference (p = 0.012), while the other 4 rings showed statistically insignificant difference (p &gt;0.05) .On the other hand, implicit time latency (Pl) showed statistically insignificant difference between preoperative and postoperative values (p &gt;0.05) in all macular rings. Conclusion There is a minimal change in macular morphology after Epi-on accelerated CXL in progressive keratoconus, however, no significant change in macular function without any structural changes in progressive keratoconus 6 weeks postoperatively. A longer follow-up period studies are recommended to provide more information.

Outcomes of two different treatment modalities in mild to moderate keratoconus

PurposeTo describe visual and refractive outcomes of intrastromal corneal ring segments (ICRS) and toric implantable collamer lenses (TICL) implantation in cases of mild and moderate keratoconus.MethodsA prospective descriptive interventional case series. 40 eyes were allocated into two groups. First group (20 eyes) was treated with corneal collagen crosslinking (CXL) 1 month after ICRS implantation and the second group was treated using TICL after 1 year of CXL.ResultsBoth groups showed statistically significant improvement in spherical equivalent, cylindrical refraction, uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) over the follow-up period.ConclusionBoth ICRS and TICL are effective in treatment of mid and moderate keratoconus with more predictable visual results with TICL.

Inflammatory profile of keratoconic corneal epithelium

BackgroundRecent studies have presented inflammatory features on keratoconus (KC) and many inflammatory markers are described in the tears of patients with this disease. The KC pathogenesis is still unknown just like the correlation with inflammatory patterns. However, environmental and genetic issues may be part of the progress of KC. In addition, some systemic features, such as allergy and obesity, seem to be related to the progression of KC. Our purpose was to evaluate the neuropeptides vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), chemokines ligand 2 (CCL-2) and 5 (CCL-5), and interleukins 6 (IL-6) and 8 (IL-8) on corneal epithelial cells and blood of patients with KC and in healthy controls. In addition, the neutrophil-to-lymphocyte ratio (NLR) was evaluated to predict inflammation.MethodsThis including prospective observational study included 32 KC patients who underwent corneal crosslinking (CXL) and 32 control patients who underwent photorefractive keratectomy (PRK). Patients’ corneal epithelial cells were removed surgically, and blood (buffy coat) was analyzed. Samples in triplicate were evaluated on rt-PCR for neuropeptides (VIP e NPY), interleukins (IL-6 e IL-8), and chemokines (CCL-2 and CCL-5).ResultsOur study showed statistically higher CCL-5 and IL-8 on corneal epithelial cells in patients with KC. Blood cells were statistically higher in VIP and NPY in the KC group. Interleukin-8 on blood cells was statistically significant in KC’S group; for CCL-2 and CCL-5 they were statistically lower in patients with KC compared with controls. NLR showed no difference between the groups.ConclusionsOur data support the findings of other studies that suggested altering KC status, such as inflammatory corneal disease. The presence of IL-8 in the cornea and blood samples of KC’s group suggested systemic disease with a possible local or repercussion action. Further studies are warranted to elucidate KC pathogenesis and its correlation to systemic disease.

The relationship between keratan sulfate glycosaminoglycan density and mechanical stiffening of CXL treatment

The corneal stroma is primarily composed of collagen fibrils, proteoglycans, and glycosaminoglycans (GAGs). It is known that corneal crosslinking (CXL) treatment improves mechanical properties of the cornea. However, the influence of stromal composition on the strengthening effect of CXL procedure has not been thoroughly investigated. The primary objective of the present research was to characterize the effect of keratan sulfate (KS) GAGs on the efficacy of CXL therapy. To this end, the CXL method was used to crosslink porcine corneal samples from which KS GAGs were enzymatically removed by keratanase II enzyme. Alcian blue staining was done to confirm the successful digestion of GAGs and uniaxial tensile experiments were performed for characterizing corneal mechanical properties. The influence of GAG removal and CXL treatment on resistance of corneal samples against enzymatic pepsin degradation was also quantified. It was found that removal of KS GAGs significantly softened corneal tensile properties (P < 0.05). Moreover, the CXL therapy significantly increased the tensile stiffness of GAG-depleted strips (P < 0.05). GAG-depleted corneal buttons were dissolved in the pepsin digestion solution significantly faster than control samples (P < 0.05). The CXL treatment significantly increased the time needed for complete pepsin digestion of GAG-depleted disks (P < 0.05). Based on these observations, we concluded that KS GAGs play a significant role in defining tensile properties and structural integrity of porcine cornea. Furthermore, the stiffening influence of the CXL treatment does not significantly depend on the density of corneal KS GAGs. The findings of the present study provided new information on the relation between corneal composition and CXL procedure mechanical effects.

Corneal cross-linking for treatment of keratoconus relapse in post-keratoplasty eyes.

Keratoconus relapse after penetrating keratoplasty is a rare condition that may result in severe visual deterioration and corneal graft thinning. Therefore, treatment to stabilize the cornea should be considered. The purpose of this study was to evaluate the safety and efficacy of Corneal Cross-Linking (CXL) in eyes with relapse of keratoconus after penetrating keratoplasty for keratoconus. A retrospective review of eyes that developed keratoconus relapse following a penetrating keratoplasty and treated with CXL. The main outcome measures were change in maximal keratometry (Kmax), best-corrected distance visual acuity (BCVA), thinnest corneal thickness (TCT) and central corneal thickness (CCT), and complications. We identified 10 consecutive eyes of 9 patients. Preoperative median BCVA before the CXL and 1year after the CXL procedure remained stable (p = 0.68). The median (IQR) of Kmax improved from 63.2 (24.9) D before the CXL procedure to 62.2 (27.1) D at 1year postoperatively (P = 0.028). Median TCT and CCT also remained with no significant change 1year after CXL. No complications were noted following the procedure. CXL in eyes with keratoconus relapse after keratoplasty is a safe and effective procedure enabling not only visual stabilization but also might bring keratometry improvement. Routine follow-up after keratoplasty should be performed for early detection of keratoconus relapse and CXL is timely advised when such a relapse is documented.

Prospective Observational Study Evaluating Systemic Hormones and Corneal Crosslinking Effects in Keratoconus

To evaluate associations between hormone levels and corneal parameters in patients with keratoconus (KC), before and after photooxidative corneal collagen crosslinking (CXL). Prospective, observational cohort study. Twenty-eight patients with KC who were scheduled for CXL at Aarhus University Hospital in Denmark. Androgen (dehydroepiandrosterone sulfate [DHEA-S]) and estrogen (estrone and estriol) plasma levels were measured and clinical assessments were performed before CXL and 2 to 3 months post-CXL, comparing the CXL eye with the control eye from the same participant. Associations between hormone levels and maximum corneal curvature (Kmax) and minimum central corneal thickness (CCtmin) before and after CXL. Corneal collagen crosslinking was associated with a 2% reduction in Kmax values in the CXL eye, post-CXL, from baseline (median, 56.8 diopters [D]; 95% confidence interval [CI], 50.4-60.3) to the second visit (55.7 D; 95% CI, 50.4-58.8; P < 0.001). Systemic DHEA-S levels were 5 to 6 orders of magnitude higher than estriol or estrone concentrations in plasma. Importantly, estriol levels, rather than DHEA-S or estrone levels, were more closely correlated with Kmax before CXL (Spearman's r= 0.55, P= 0.01). Post-CXL Kmax and CCtmin were not associated with DHEA-S, estrone, or estriol plasma levels at the same timepoint. This study provides supporting evidence based on a KC clinical population that systemic estrogen levels may influence corneal parameters (curvature and thickness) pre-CXL. Further studies evaluating the interplay between the therapeutic benefits of CXL and systemic hormone distributions are needed to determine if perturbation of the local corneal microenvironment influences endocrine function. The authors have no proprietary or commercial interest in any materials discussed in this article.

Combined Photorefractive Keratectomy and Corneal Cross-Linking for Keratoconus and Ectasia: The Athens Protocol.

Customized photorefractive keratectomy with minimal tissue ablation combined with corneal cross-linking seems to be a long-term safe and effective strategy for anatomical and visual management of keratoconus, postsurgical ectasia, and other ectasia management. Multiple published studies, many with long-term follow-up, have supported the Athens Protocol and its various forms as a means to manage corneal ectatic disorders, which not only stabilize corneal shapes but also improve functional vision.

Development and validation to predict visual acuity and keratometry two years after corneal crosslinking with progressive keratoconus by machine learning.

To explore and validate the utility of machine learning (ML) methods using a limited sample size to predict changes in visual acuity and keratometry 2 years following corneal crosslinking (CXL) for progressive keratoconus. The study included all consecutive patients with progressive keratoconus who underwent CXL from July 2014 to December 2020, with a 2 year follow-up period before July 2022 to develop the model. Variables collected included patient demographics, visual acuity, spherical equivalence, and Pentacam parameters. Available case data were divided into training and testing data sets. Three ML models were evaluated based on their performance in predicting case corrected distance visual acuity (CDVA) and maximum keratometry (Kmax) changes compared to actual values, as indicated by average root mean squared error (RMSE) and R-squared (R2) values. Patients followed from July 2022 to December 2022 were included in the validation set. A total of 277 eyes from 195 patients were included in training and testing sets and 43 eyes from 35 patients were included in the validation set. The baseline CDVA (26.7%) and the ratio of steep keratometry to flat keratometry (K2/K1; 13.8%) were closely associated with case CDVA changes. The baseline ratio of Kmax to mean keratometry (Kmax/Kmean; 20.9%) was closely associated with case Kmax changes. Using these metrics, the best-performing ML model was XGBoost, which produced predicted values closest to the actual values for both CDVA and Kmax changes in testing set (R2 = 0.9993 and 0.9888) and validation set (R2 = 0.8956 and 0.8382). Application of a ML approach using XGBoost, and incorporation of identifiable parameters, considerably improved variation prediction accuracy of both CDVA and Kmax 2 years after CXL for treatment of progressive keratoconus.

First Experience of Combined Treatment of Corneal and Graft Ulcers in Preschool Children Using Local Ultraviolet Crosslinking (Clinical Cases)

Purpose: to evaluate the results of a new combined method for the treatment of corneal and graft ulcers in preschool children, including local ultraviolet crosslinking (UVA CL) of corneal collagen and amniotic membrane transplantation (AMT).Methods. 1 patient 4 years old with a corneal ulcer and transplant disease after penetrating subtotal keratoplasty and 1 child 6 years old with a corneal ulcer of herpetic etiology was under observation for 1 year. The treatment included 3–5 consecutive procedures of local UVA CL of the cornea lasting 5 min. and amniotic membrane transplantation (AMT) after the first CL procedure. Biomicroscopy with fluorescein test and optical coherence tomography (OCT Spectralis, Heidelberg Engineering, Germany) were used to dynamically monitor the clinical course of corneal and graft ulcers. Local CL was performed using a new Keratolink device (OA Elatomsky Instrument Plant, Russia). Immediately after the 1st CL procedure, a TAM operation was performed under operating conditions under anesthesia, after which 2–4 more local CL procedures were performed sequentially every 3 days.Results. During treatment with each subsequent CL procedure, the clinical condition of the eyes improved: inflammation was relieved, photophobia, lacrimation, blepharospasm disappeared, a gradual increase in the epithelium from the periphery of the cornea with the formation of a gentle translucent opacification was noted, vascular activity decreased, and visual acuity significantly increased. After 2–10 months, in both cases there are no active complaints, the eyes are calm, infiltrates were not determined, in their place a gentle cloud-like translucent opacity formed, including in a child after keratoplasty. Vessels are empty.Conclusion. Combined treatment of corneal and graft ulcers in children (local UVA CL together with TAM) demonstrated high therapeutic efficacy, ensured stable corneal epithelialization in a short time and improved visual functions at the end of the inflammatory process. This method can significantly expand the possibilities of treating ulcerative lesions of the cornea and graft in preschool children.

Five-year results of iontophoresis-assisted transepithelial corneal cross-linking for keratoconus

PurposeTo assess long-term efficacy and safety of iontophoresis-assisted transepithelial corneal cross-linking (I-CXL) for keratoconus.Patients and methodsTwenty-seven eyes of 21 patients (15 M, 6F) affected by progressive keratoconus were evaluated. All subjects were treated with iontophoresis-assisted transepithelial CXL. The patients were examined at baseline and each 6 months after the CXL procedure. Only subjects who completed the follow-up of 5 years were considered in this study. The main outcome measures were uncorrected visual acuity (UCVA), corrected visual acuity (CDVA), corneal transparency and corneal parameters such as K-max, central corneal thickness (CCT) and at the thinnest point, and high-order ocular aberrations (HOAs). The ABCD system was used to determine the progression and re-progression of ectasia.SettingOphthalmology Clinic, University Hospital of Messina, Messina, Italy.ResultsAt 5 years, significant improvements of UCVA from 0.53 ± 0.33 logMAR to 0.4 ± 0.33 logMAR (p = 0.001) and HOAs (p = 0.01) were registered. No significant changes of CDVA (p = 0.4), K-max (p = 0.75), CCT (p = 0.5) were observed at the end of follow-up period.The ABCD system showed re-progression in 25.9% of eyes after 5 years. No adverse events such as corneal opacities and infections were reported.ConclusionsIontophoresis-assisted transepithelial CXL resulted to be safe and effective to stabilize progressive keratoconus in adults at a long-term follow-up.

A Novel Procedure for Keratoconus/Corneal Ectasia Treating Epithelial Compensation of Higher-Order Aberrations, Topographic Guided Ablation, and Corneal Cross Linking - The CREATE+CXL Protocol.

To present the outcomes of a retrospective study in keratoconus/corneal ectasia patients of treating the higher order aberrations compensated for the corneal epithelium in addition to topographic guided ablation followed by corneal cross linking. Twenty-seven eyes of 14 patients were treated for keratoconus/corneal ectasia utilizing trans-epithelial topographic guided ablation photorefractive keratectomy (PRK) for treatment of corneal higher order aberrations and lower order astigmatism followed immediately by 15-minute cross linking were examined retrospectively. Six-month results were analyzed via measurement of vision, refraction, residual higher-order aberrations (HOAs), residual lower-order and higher-order aberrations, as well as for loss or gains of lines of best corrected visual acuity. All eyes save one had reduction in K1, K2, K Max, and K Mean. All eyes had reduction in manifest astigmatism, Contoura measured astigmatism, 57% reduction of higher-order aberrations (HOA), and 53% reduction of higher-order aberrations grouped with lower-order aberrations (Grouped). Nearly all (96.3%) eyes achieved 20/40 vision or better, 20 eyes had 1-7 lines gained of vision, and no eyes had any loss of lines of vision. Use of the CREATE+CXL protocol combined with 15-minute corneal cross linking results in a significant increase in HOA reduction, as well as a significant improvement in corrected distance visual acuity over past procedures.

Long Term Corneal Flattening After Corneal Crosslinking in Patients with Progressive Keratoconus.

We evaluate the long-term visual, refractive, and keratometric outcomes after corneal crosslinking (CXL) in patients with progressive keratoconus (KC) and the incidence of an extreme corneal flattening effect. Oftalmosalud Institute of Eyes, Lima, Perú. Retrospective cohort study. Forty-five eyes that underwent CXL with epithelial removal between June 2006 and September 2011. Data analysis was performed at preoperative evaluation, 1 year postoperatively, and at least 10 years or more postoperatively. Outcome measures included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and Scheimpflug (Pentacam) analysis. Progression was defined by an increase in steep keratometry (Ks) of 1.5D or greater between 2 examinations. Extreme flattening effect was defined as a decrease in K values equal to or greater than 5 diopters (D). Mean follow-up time was 11 ± 1.07 years (range 10-13 years). There was a significant improvement in Ks, UCVA, CDVA, and spherical equivalent at the last visit. The overall rate of progression was 2.22% (1/45). Extreme flattening was observed in 15.5% (7/45) of the eyes, and this was associated with a loss of CDVA in 4.44% (2/45) of the eyes. One eye with corneal flattening of 11.5 D lost 7 lines of CDVA and required corneal transplantation. CXL is a safe and effective procedure to stop the progression of KC with a good overall long-term success rate. Extreme corneal flattening may be more common than commonly recognized, and severe corneal flattening associated with a decrease in CDVA may occur.

A "T.E.S.T." hydrogel bioadhesive assisted by corneal cross-linking for in situ sutureless corneal repair.

Corneal transplantation is an effective clinical treatment for corneal diseases, which, however, is limited by donor corneas. It is of great clinical value to develop bioadhesive corneal patches with functions of "Transparency" and "Epithelium & Stroma generation", as well as "Suturelessness" and "Toughness". To simultaneously meet the "T.E.S.T." requirements, a light-curable hydrogel is designed based on methacryloylated gelatin (GelMA), Pluronic F127 diacrylate (F127DA) & Aldehyded Pluronic F127 (AF127) co-assembled bi-functional micelles and collagen type I (COL I), combined with clinically applied corneal cross-linking (CXL) technology for repairing damaged cornea. The patch formed after 5min of ultraviolet irradiation possesses transparent, highly tough, and strongly bio-adhesive performance. Multiple cross-linking makes the patch withstand deformation near 600% and exhibit a burst pressure larger than 400mmHg, significantly higher than normal intraocular pressure (10-21mmHg). Besides, the slower degradation than GelMA-F127DA&AF127 hydrogel without COL I makes hydrogel patch stable on stromal beds in vivo, supporting the regrowth of corneal epithelium and stroma. The hydrogel patch can replace deep corneal stromal defects and well bio-integrate into the corneal tissue in rabbit models within 4 weeks, showing great potential in surgeries for keratoconus and other corneal diseases by combining with CXL.

Current Surgical Options in the Management of Cataract in Keratoconus Patients

Abstract An ectatic cornea presents unique challenges at the time of cataract surgery. Keratoconus is the most common corneal ectasia, affecting 2–54.5 per 100,000 people. Cataract surgery in keratoconus often yields suboptimal visual outcomes, with &lt; 50% achieving within +/−0.5D of the desired refractive target in mild–moderate disease and worsening to 0%–18% in severe disease. Improving postsurgical visual outcomes requires a multifaceted approach, starting with modification of risk factors and patient education. Disease progression should be halted prior to any final surgical plan, often requiring the use of corneal crosslinking to create long-term stability in keratometry prior to cataract surgery. Inaccurate keratometry is a common and significant source of postoperative refractive error, and recent developments in keratoconus-specific intraocular lens (IOL) power calculations have attempted to address this. Despite the above strategies, correction of postsurgical refractive error may be done using corrective lenses or IOL-based techniques. Additionally, surgical strategies such as topography-guided photorefractive keratectomy, intrastromal ring segments, or corneal allogenic intrastromal ring segments can be performed pre- or postoperatively to enhance vision. This review seeks to provide an overview of the considerations and available strategies for cataract surgery in patients with keratoconus.