Epithelial Debridement Research Articles

Aquaporin 5 Facilitates Corneal Epithelial Wound Healing and Nerve Regeneration by Reactivating Akt Signaling Pathway

Aquaporins (AQPs) are a highly conserved group of membrane proteins that play critical roles in water and small solute transport across epithelial and endothelial barriers. The aim of this study was to determine whether AQP5, a well-known water channel protein, also plays a role in corneal epithelial wound healing. AQP5 knockout (AQP5-/-) mice were generated using CRISPR/Cas9. A corneal wound healing model was established using epithelial debridement of corneas. The time to corneal epithelial and nerve regeneration was significantly delayed in the AQP5-/- mice. Reduction in Ki-67-positive cells and nerve growth factor (NGF) expression was confirmed in the AQP5-/- mice during healing. Epithelial and nerve regeneration rates were significantly increased in the AQP5-/- mice after treatment with NGF, which was accompanied by recovered levels of phosphorylated Akt. NGF treatment also improved the recovery of corneal nerve fiber density and sensitivity in the AQP5-/- mice. While the promotion of NGF induced corneal epithelial and nerve regeneration, Akt inhibitor reversed Akt reactivation. A significant impairment of corneal wound healing in the AQP5-/- mice resulted from distinct defects in corneal epithelial cell proliferation and nerve regeneration. These results provide evidence for the involvement of aquaporin in cell proliferation and suggest that AQP5 induction could be a potential therapy for accelerating the resurfacing of corneal defects.

Pannexin1: Role as a Sensor to Injury Is Attenuated in Pretype 2 Corneal Diabetic Epithelium.

Epithelial wound healing is essential to repair the corneal barrier function after injury and requires coordinated epithelial sheet movement over the wounded region. The presence and role of pannexin1 on multilayered epithelial sheet migration was examined in unwounded and wounded corneal epithelium from C57BL/6J (B6) control and diet-induced obese (DiO) mice, a pretype 2 diabetic model. We hypothesize that pannexin1 is dysregulated, and the interaction of two ion-channel proteins (P2X7 and pannexin1) is altered in pretype 2 diabetic tissue. Pannexin1 was found to be present along cell borders in unwounded tissue, and no significant difference was observed between DiO and B6 control. However, an epithelial debridement induced a striking difference in pannexin1 localization. The B6 control epithelium displayed intense staining near the leading edge, which is the region where calcium mobilization was detected, whereas the staining in the DiO corneal epithelium was diffuse and lacked distinct gradation in intensity back from the leading edge. Cells distal to the wound in the DiO tissue were irregular in shape, and the morphology was similar to that of epithelium inhibited with 10Panx, a pannexin1 inhibitor. Pannexin1 inhibition reduced mobilization of calcium between cells near the leading edge, and MATLAB scripts revealed a reduction in cell-cell communication that was also detected in cultured cells. Proximity ligation was performed to determine if P2X7 and pannexin1 interaction was a necessary component of motility and communication. While there was no significant difference in the interaction in unwounded DiO and B6 control corneal epithelium, there was significantly less interaction in the wounded DiO corneas both near the wound and back from the edge. The results demonstrate that pannexin1 contributes to the healing response, and P2X7 and pannexin1 coordination may be a required component of cell-cell communication and an underlying reason for the lack of pathologic tissue migration.

Combination of violet light irradiation and collagenase treatments in a rabbit model.

To investigate the use of collagenase type II for generating a rabbit model of keratoconus and to evaluate the impact of violet light (VL) irradiation on the disease model. Six Japanese White rabbits were used. After epithelial debridement, the collagenase group was treated with a collagenase type II solution for 30min; the control group was treated with a solution without collagenase. Three rabbits also underwent VL irradiation (375nm, irradiance 310μW/cm2) for 3h daily for 7days after topical collagenase application. Slit-lamp microscopy, steep keratometry (Ks), corneal astigmatism, central corneal thickness, and axial length were examined before and after the procedure. The corneas were obtained on day 7 for biomechanical evaluation. A significant increase in Ks and corneal astigmatism was observed in the collagenase and VL irradiation groups compared with the control group at day 7. No significant difference was found in the change in corneal thickness between the groups. The elastic modulus at 10% strain but not at 3% and 5% strain in the collagenase group was significantly lower than that in the control group. There was no significant difference in the elastic modulus at each level of strain between the collagenase and VL irradiation groups. The average axial length at day 7 in the collagenase group was significantly longer than that in the control group. Collagenase type II treatment can mimic keratoconus with increased corneal keratometry and astigmatism. There was no significant difference in the observed elastic behaviour of normal and ectatic corneas under physiologically relevant stress levels. VL irradiation did not cause regression of corneal steepening in this model with short-term observation.

Topical calcitriol application promotes diabetic corneal wound healing and reinnervation through inhibiting NLRP3 inflammasome activation

Vitamin D (VD) deficiency delays corneal wound healing in those with diabetes, which cannot be rescued with supplemental diet. Here, we employed topical calcitriol application to evaluate its efficiency in corneal wound healing and reinnervation in diabetic mice. Type 1 diabetic mice were topically administrated calcitriol, or subconjunctivally injected with NLRP3 antagonist MCC950 or IL-1β blocking antibody after epithelial debridement. Serum VD levels, corneal epithelial defect, corneal sensation and nerve density, NLRP3 inflammasome activation, neutrophil infiltration, macrophage phenotypes, and gene expressions were examined. Compared with those of normal mice, diabetic mice showed reduced serum VD levels. Topical calcitriol application promoted corneal wound healing and nerve regeneration, as well as sensation recovery in diabetic mice. Moreover, calcitriol ameliorated neutrophil infiltration and promoted the M1-to-M2 macrophage transition, accompanied by suppressed overactivation of the NLRP3 inflammasome. Treatment with NLRP3 antagonist or IL-1β blockage demonstrated similar improvements as those of topical calcitriol application. Additionally, calcitriol administration upregulated desmosomal and hemidesmosomal gene expression in the diabetic cornea. In conclusion, topical calcitriol application promotes corneal wound healing and reinnervation during diabetes, which may be related to the suppression of the overactivation of NLRP3 inflammasome.

Impairment of corneal epithelial wound healing is association with increased neutrophil infiltration and reactive oxygen species activation in tenascin X-deficient mice

The purpose of the study was to uncover the role of tenascin X in modulation of healing in mouse corneas subjected to epithelium debridement. Healing in corneas with an epithelial defect was evaluated at the levels of gene and protein expression. Wound healing-related mediators and inflammatory cell infiltration were detected by histology, immunohistochemistry and real-time RT-PCR. Tenascin X protein was upregulated in the wounded wild-type (WT) corneal epithelium. The lack of tenascin X impaired closure of an epithelial defect and accelerated infiltration of neutrophils into the wound periphery as compared to the response in WT tissue. Expression of wound healing-related proinflammatory and reparative components, i.e., interleukin-6, transforming growth factor β, matrix metalloproteinases, were unaffected by the loss of tenascin X expression. Marked accumulation of malondialdehyde (a lipid peroxidation-derived product) was observed in KO healing epithelia as compared with its WT counterpart. Neutropenia induced by systemic administration of a specific antibody rescued the impairment of epithelial healing in KO corneas, with reduction of malondialdehyde levels in the epithelial cells. Finally, we showed that a chemical scavenging reactive oxygen species reversed the impairment of attenuation of epithelial repair with a reduction of tissue levels of malondialdehyde. In conclusion, loss of tenascin X prolonged corneal epithelial wound healing and increased neutrophilic inflammatory response to debridement in mice. Tenascin X contributes to the control of neutrophil infiltration needed to support the regenerative response to injury and prevent the oxidative stress mediators from rising to cytotoxic levels.

Risk factors for keratoconus progression after treatment by accelerated cross-linking (A-CXL): A prospective 24-month study

Identification of potential predictive factors for keratoconus progression after treatment by accelerated Cross-linking (A-CXL) SECONDARY OBJECTIVES: Evaluation of clinical and topographic outcomes for two years following accelerated cross-linking treatment for progressive keratoconus including: best spectacle corrected visual acuity (BSCVA), thinnest pachymetry, maximum keratometry (Kmax), cylinder. Prospective, interventional, monocentric study. SITE: Metz-Thionville Regional Medical Center, Lorraine University, Mercy Hospital, Metz, France. We included 82 eyes of 60 patients between March 2014 and June 2016 who underwent accelerated corneal cross-linking (A-CXL) with epithelial debridement for progressive keratoconus, with a minimum follow-up of 2 years. A complete clinical evaluation and corneal topography were performed before cross-linking, and subsequently at 6, 12 and 24 months post-procedure. The following parameters were monitored during follow-up: best spectacle corrected visual acuity (BSCVA), minimal pachymetry, maximum keratometry (Kmax), mean anterior and posterior curvatures, maximum posterior curvature, presence of optical aberrations, subdivided into spherical aberration, coma, astigmatism, higher order optical aberrations and residual optical aberrations. After a 2-year follow-up, two groups, defined as "responders" and "non-responders" to treatment, were separated for analysis, and their initial characteristics were compared. Data for 82 eyes of 60 patients with progressive keratoconus with a mean age of 24±7 years were studied. Fourteen eyes (17.1%) showed signs of progression after treatment by A-CXL (non-responders), and 68 eyes (82.9%) showed stabilization of the disease (responders). Characteristics of non-responding eyes after A-CXL included a younger mean age (20±5 vs. 25±7 years) (P=0.04) and a lower initial mean BCVA for non-responders of 0.44±0.16 logMAR vs. 0.29±0.19 logMAR (P=0.03). Non-responders also had a higher mean maximal posterior curvature (AKB) of -10.84±1.72D vs. -9.46± 1.12D (P=0.03). They also showed more higher order optical aberrations (3.84±1.72D vs. 2.4±1.02D; P=0.01), including coma (3.85±1.81D vs. 2.1±1.01D; P=0.03) and more residual aberrations than responders (1.05±0.44D vs. 0.45±0.6D; P=0.005). No significant differences were found between responders and non-responders for the other parameters in our study. Eyes with progressive keratoconus who did not respond to A-CXL treatment were the most aggressive cases in the youngest patients, with highest maximum corneal curvatures and most pronounced optical aberrations. These patients should be informed in advance of the high risk of non-response to A-CXL treatment, and of the potential need for additional treatment in the future.

Dose-dependent therapeutic effects of topical 1,25 OH-vitamin D3 on corneal wound healing.

Conflicting results have been reported regarding the effects of 1,25 OH-vitamin D3 on corneal wound healing. Therefore, we undertook this study to determine whether the observed differences are dose related. The dose-dependent effects of 1,25 OH-vitamin D3 on corneal wound healing were evaluated using scratch assays on human corneal limbal-epithelial cells (HCLEs) and in vivo mouse corneal epithelial debridement. To evaluate the anti-inflammatory effects of 1,25 OH-vitamin D3, macrophages were stimulated by a Toll-Like Receptor (TLR) ligand followed by treatment with the 10-6M, 10-7M and 10-8M 1,25 OH-vitamin D3. 10-7M 1,25 OH-vitamin D3 induced faster scratch wound closure compared with the other concentrations of 1,25 OH-vitamin D3 tested (10-6M and 10-8M), and 0.02% ethanol as a control (85.8 ± 2.6%, 33.9 ± 6.74%, 32.6 ± 3.35%, and 31.6 ± 3.99%, respectively, P < 0.0001). Single-time treatment with 10-7M 1,25 OH-vitamin D3 also significantly improved the healing of mouse corneal epithelial wound compared to multiple treatments and control (74.1 ± 17.3% vs. 52.4 ± 11.6% and 45.8 ± 13.4%, respectively). Polyinosinic: polycytidylic acid (poly [I:C])-stimulated macrophage cells and 10-7M 1,25 OH-vitamin D3 significantly decreased gene expression of ICAM1, TLR3, IL6, IL8, and TNFα (P < 0.0001). Our results suggest the dose-dependent therapeutic effect of 1,25 OH-vitamin D3 in corneal wound healing which can be potentially used as a non-invasive option in the treatment of corneal wounds.

Clinical trial of topical insulin and sodium hyaluronate in the treatment of epithelial defects produced by intraoperative corneal epithelial debridement during pars plana vitrectomy in diabetics

Clinical trial of topical insulin and sodium hyaluronate in the treatment of epithelial defects produced by intraoperative corneal epithelial debridement during pars plana vitrectomy in diabetics

Correction: The Effectiveness of Corneal Epithelial Debridement Performed with an Alcohol-Impregnated Sponge.

Correction to: The Effectiveness of Corneal Epithelial Debridement Performed with an Alcohol-Impregnated SpongeKlin Monbl Augenheilkd 2022; 239(02): 185-190DOI: 10.1055/a-1327-3156

Neuronal-epithelial cell alignment: A determinant of health and disease status of the cornea

PurposeHow sensory neurons and epithelial cells interact with one another, and whether this association can be considered an indicator of health or disease is yet to be elucidated. MethodsHerein, we used the cornea, Confetti mice, a novel image segmentation algorithm for intraepithelial corneal nerves which was compared to and validated against several other analytical platforms, and three mouse models to delineate this paradigm. For aging, eyes were collected from 2 to 52 week-old normal C57BL/6 mice (n ≥ 4/time-point). For wound-healing and limbal stem cell deficiency, 7 week-old mice received a limbal-sparing or limbal-to-limbal epithelial debridement to their right cornea, respectively. Eyes were collected 2–16 weeks post-injury (n=4/group/time-point), corneas procured, immunolabelled with βIII-tubulin, flat-mounted, imaged by scanning confocal microscopy and analyzed for nerve and epithelial-specific parameters. ResultsOur data indicate that nerve features are dynamic during aging and their curvilinear arrangement align with corneal epithelial migratory tracks. Moderate corneal injury prompted axonal regeneration and recovery of nerve fiber features. Limbal stem cell deficient corneas displayed abnormal nerve morphology, and fibers no longer aligned with corneal epithelial migratory tracks. Mechanistically, we discovered that nerve pattern restoration relies on the number and distribution of stromal-epithelial nerve penetration sites. ConclusionsMicrostructural changes to innervation may explain corneal complications related to aging and/or disease and facilitate development of new assays for diagnosis and/or classification of ocular and systemic diseases.

Transepithelial corneal collagen cross-linking using iontophoresis versus the Dresden protocol in progressive keratoconus: A meta-analysis.

Standard epithelium-off collagen cross-linking using Dresden protocol (S-CXL) is the standard of care for progressive keratoconus. Despite its efficacy, epithelial debridement is associated with pain, delayed visual rehabilitation, stromal oedema and haze. Minimising these complications while achieving a comparable efficacy remains an unmet need. Comparative studies between transepithelial iontophoresis-assisted CXL (I-CXL) and S-CXL reporting the outcomes of visual, refractive, topographic, aberrometry, demarcation line, endothelial cell density, confocal microscopy or complications were identified from databases. Assessments of publication bias, meta-analyses, sensitivity analysis, subgroup analysis, and meta-regressions were performed. In this meta-analysis, 586 eyes from three randomised controlled trials and seven comparative studies were analysed. No differences were found in the change in uncorrected/corrected distance visual acuities, mean/maximum keratometry, central corneal thickness, higher order aberration, spherical aberration, coma, subbasal nerve/anterior stromal keratocyte density and demarcation line depth in both CXL protocols (P ≥ .052). However, I-CXL resulted in less thinning at the minimum pachymetry (standardised mean difference 0.25; 95% confidence interval [CI] 0.06-0.44). More importantly, there was a significant reduction in complications following I-CXL (odds ratio 0.30; 95% CI 0.12-0.75). Meta-regression analyses on demarcation line depth and complication suggested that I-CXL was more effective than S-CXL when baseline maximum keratometry was >55.2 D and the risk of complication was independent of other baseline covariates. I-CXL has a more favourable safety profile, as evidenced by the available literature, with less thinning at the minimum pachymetry and reduced risk of complications while achieving comparable effects on visual, refractive, topographic, aberrometry, and morphological outcomes as S-CXL.

The Effectiveness of Corneal Epithelial Debridement Performed with an Alcohol-Impregnated Sponge.

To evaluate the clinical outcomes of patients who underwent corneal surgery with debridement of epithelium by localised application of an alcohol-impregnated sponge instead of the usual alcohol reservoir method. This study retrospectively included 52 eyes of 27 patients who underwent LASEK (laser-assisted subepithelial keratectomy) and CXL (cross-linking) surgery after application of this alcohol-assisted debridement method between January 2019 and April 2019. Twenty-four patients who underwent LASEK and three patients who underwent CXL surgery were included in this study, which comprised a total of 52 eye operations. Epithelial debridement was performed after placing a 20% ethanol-impregnated sponge on the cornea for 20 seconds. The mean pachymetry value was 509.40 ± 30.37 µm, the mean preoperative spherical equivalent was - 2.14 ± 1.02 dioptres, and the highest myopia and astigmatism values were - 4.25 dioptres and - 2.75 dioptres, respectively. It was seen that the corneal epithelium was completely and easily debrided in a size identical to that of the applied sponge. Complete debridement of the corneal epithelium can be performed quickly, safely, and easily with this specially prepared sponge.

Corneal Cross-linking at the Slit Lamp.

To describe a new surgical technique where corneal cross-linking (CXL) (to treat corneal ectasias) and photo-activated chromophore for keratitis-CXL (PACK-CXL) are performed while the patient is seated in an upright position at the slit lamp. Topical anesthesia is applied in the waiting room, 10 minutes before the procedure. Once in the office or procedure room, eyelids and periorbital areas are disinfected with chloramphenicol and the patient is seated at the slit lamp. Epithelial debridement is performed with a cotton swab soaked in freshly prepared 40% ethanol, using 70 seconds of tapping, followed by gentle pressure to remove the epithelium. The patient is placed in the supine position for riboflavin application for 10 minutes. Stromal thickness is assessed using ultrasound pachymetry after 5 and 10 minutes. Finally, the patient is returned to the slit lamp to receive ultraviolet irradiation. CXL at the slit lamp is an easy-to-perform technique that substantially reduces the infrastructure needed to perform CXL and PACK-CXL procedures. A significant advantage of allowing CXL treatment at the slit lamp is that CXL technology can now be used in clinics that do not have easy access to an operating room infrastructure. Slit-lamp CXL can also reduce procedure costs by eliminating the technical fees related to the use of an operating room, making this treatment not only more accessible for patients, but also affordable. [J Refract Surg. 2021;37(2):78-82.].

Pigment Epithelium-Derived Factor Peptide Promotes Corneal Nerve Regeneration: An In Vivo and In Vitro Study.

PurposeTo investigate the potential of a pigment epithelium-derived factor (PEDF) peptide 44-mer to promote nerve regeneration in a rabbit corneal nerve injury model to demonstrate its neurotrophic ability in cultivated mouse trigeminal neuron cells.MethodsSubconjunctival or intrastromal injection of 44-mer on the cornea was performed in a rabbit model of corneal nerve injury created by corneal epithelial debridement. Immunocytochemical analysis (44-mer, anti-tubulin III, SMI312, CD11b, and α-SMA) and in vivo confocal microscopy were performed. Corneal sensation was estimated using a Cochet-Bonnet corneal esthesiometer. Primary cultivated mouse trigeminal neurons were used to examine the in vitro neurotrophic ability of 44-mer. The cellular morphology and the immunocytochemical staining with anti-tubulin III and SMI312 in different concentrations of 44-mer were compared, and a quantitative assessment of neurite outgrowth was performed.ResultsImmunohistochemical staining showed the retention of 44-mer in the corneal stroma for at least 7 days after a single dose of corneal intrastromal injection and promoted corneal nerve regeneration revealed by in vivo confocal microscopy. Corneal esthesiometer demonstrated gradual recovery of the corneal sensation in 44-mer-treated eyes with a lower corneal touch threshold than wounded vehicles and closer to baseline at 3 weeks after corneal injury (P < 0.001). In vitro studies showed a dose-dependent neurotrophic effect of 44-mer in cultivated trigeminal neuron cells.ConclusionsThe 44-mer showed in vivo and in vitro corneal neurotrophic abilities. Our results suggest that intrastromal injection of 44-mer into the corneal stroma may have a potential role in treating diseases related to corneal nerve damage.

Effects of Intravenous Flunixin Meglumine, Phenylbutazone, and Acupuncture on Ocular Pain Scores in the Horse: A Pilot Study

In this controlled, blinded, randomized block pilot study, the main objective was to evaluate the effectiveness of intravenous flunixin meglumine, phenylbutazone, and acupuncture on ocular pain relief using a multifactorial pain scale in the horse. Four experimental horses underwent corneal epithelial debridement in four sessions, when a randomly selected treatment or a control was used. All horses were pain scored before corneal wounding, then at 18 time points, when 11 parameters were allocated. Differences in the area under the curve of pain scores between the treatment groups were analyzed using a paired t-test. Corneal pain was significantly reduced by the third postoperative day (P = .03) when all 11 parameters were considered. Five ocular signs showed significant differences between treatments and proved to be good indicators of ocular pain. The other parameters (heart rate, corneal touch threshold, respond to palpation, and three behavioral parameters) were determined to be irrelevant when evaluating the degree of pain. When considering the five ocular signs, the lowest pain score was attributed to the flunixin meglumine group (1114), followed by the electroacupuncture group (1356), the phenylbutazone group (1397), and the control group (1580). There were significantly lower pain scores (P = .01) in the flunixin meglumine group when compared with those recorded in the control group during the first 46 hours. Flunixin meglumine was the most effective treatment at reducing ocular pain in the horse. In the future, a reduction in the number of pain score parameters and more precisely defined image evaluation criteria could be used.

Comparison of ocular discomfort after three different epithelial debridement techniques for corneal collagen cross-linking in keratoconus treatment.

Purpose:To compare the severity and duration of ocular discomfort after three different epithelial debridement techniques for corneal collagen cross-linking in the treatment of keratoconus.Methods:Fifty-five patients (65 eyes) known to have keratoconus were enrolled in this retrospective study. The eyes were divided into three groups based on the technique used for epithelial debridement for corneal collagen cross-linking procedure; excimer laser transepithelial phototherapeutic keratectomy was used in group 1 (18 eyes), alcohol-assisted epithelial removal was used in group 2 (27 eyes), and mechanical epithelial debridement was used in group 3 (20 eyes). Preoperative and postoperative (third month) best-corrected visual acuity (BCVA) using Snellen chart, objective refraction, and keratometry results were recorded. The results of the questionnaire obtained from the patient’s medical records were reviewed regarding their subjective evaluation of postoperative symptoms including foreign body sensation, tearing, photophobia, and burning at the end of the first postoperative week. Paired-samples t test was used to compare preoperative and postoperative clinical findings. One-way analysis of variance (ANOVA) was used to analyze the differences between three independent groups.Results:BCVA improved from 0.51 ± 0.27 to 0.58 ± 0.21 (p = 0.05). Objective mean spherical and cylindrical refraction decreased from −5.08 ± 2.78D to −4.46 ± 2.91D (p = 0.22) and from −3.45 ± 2.73D to −3.03 ± 1.97D (p = 0.25). Mean maximum keratometry reading (Kmax) decreased from 57.63 ± 4.73D to 56.13 ± 4.47D (p = 0.001). The mean score for foreign body sensation was the highest in group 3 (4.50 ± 0.53) and the lowest in group 1 (2.10 ± 1.85) (p = 0.01). The mean scores for tearing, photophobia, and burning sensation were comparable in three groups (p = 0.84, p = 0.13, and p = 0.61, respectively). The duration of photophobia was the shortest in group 1 (1.50 ± 2.37 days), followed by group 3 (2.00 ± 1.31 days) and group 2 (4.00 ± 1.83 days) (p = 0.04).Conclusions:The severity and duration of adverse subjective symptoms during the first postoperative week after corneal collagen cross-linking appear to be milder with epithelial debridement using excimer laser transepithelial technique compared with -assisted debridement and mechanical debridement.

Corneal cross‐linking in advanced keratoconus, is it still effective?

AbstractPurposeThe study aims to investigate the effectiveness of corneal cross‐linking (CXL) treatment in keratoconus patients.MethodsA total of 167 eyes of 159 progressive keratoconic patients (109 males and 58 females) aged 19 to 52 years old were included in the study. Epithelium debridement was performed for all patients, followed by riboflavin and UV‐A accelerated CXL (9.86 mW/cm2 for 9 min). To explore the effect of keratoconus severity on CXL outcomes, patients were divided into two groups based on the preoperative measurements of maximum keratometry (Kmax): Group A (Kmax &lt; 62D) and Group B (Kmax ≥ 62 D). Corrected distance visual acuity (CDVA), corneal curvature and thickness were measured pre‐CXL and at 1, 2 and 3 years post‐CXL treatment using the Oculus Pentacam.ResultsResults showed a significant improvement in CDVA on logMAR chart (0.19 ± 0.41, p = 0.04) at 3 years follow‐up. Kmax reduced significantly by 1.61 ± 3.02D, p = 0.02 (from 64.35 ± 6.85D to 63.19 ± 6.99D) at 3 years after CXL. Pachymetry measurements showed a significant reduction at 1 year (p = 0.01), 2 years (p = 0.00005) and 3 years (p = 0.000002) following CXL. CXL induced a significant reduction in Kmax measurements in Group A at 3 years follow‐up (1.50 ± 2.17D, p = 0.02); however, there was no significant change observed at 3 years following CXL in Group B (p = 0.19). Kmax reduced or at least stabilised in all patients in Group A at 3 years follow‐up; however, 25% of eyes in Group B showed a Kmax worsening of ≥1D.ConclusionsThe findings of the current study show the effectiveness of CXL to stabilise the progression of keratoconus and significantly improve corneal curvature measurements. The progression of keratoconus is more likely to stabilise after CXL in eyes with lower Kmax measurements.

Epi-Bowman keratectomy versus alcohol-assisted photorefractive keratectomy: wound healing and complications

Purpose:In Epi-Bowman Keratectomy™ (EBK), a new dynamic multi-blade single-use device (Epi-Clear™, Orca Surgical, Israel) is utilized to remove the epithelium by sweeping movements across the corneal surface. Epithelial cells are discarded. Alcohol or other chemical agents are not utilized. We wanted to compare clinical results of Epi-Clear photorefractive kertectomy (PRK) to alcohol-assisted PRK.Study design:Retrospective, comparative study.Methods:Consecutive case series: Adult patients seeking laser vision correction of myopia or myopic astigmatism without ocular diseases or prior surgery were included. The Epi-Clear PRK group comprised 50 consecutive eyes of 27 patients and the PRK group 50 eyes of 25 patients.Results:No intraoperative complications occurred. Epi-Clear PRK: At day 1, day 4, and 3 months, uncorrected distance visual acuity (UDVA) was 0.41/0.47/0.93 (decimal scale); epithelial defect diameter was 4.7/0.2/0 (mm); pain level was 3.8/0.3/0 (visual analogue scale, 0–10), respectively. At 3 months, efficacy index was 0.86 and spherical aberrations were unchanged. Three eyes (6%) showed (presumably sterile) infiltrates. PRK: At day 1, day 4, and 3 months, UDVA was 0.56/0.46/1.15; epithelial defect diameter was 6.3/0.2/0 (mm); pain level was 5.0/0.3/0, respectively. At 3 months, efficacy index was 1.1 and spherical aberrations were unchanged.Conclusion:The new method of epithelial debridement with Epi-Clear before laser ablation seems to offer fast epithelial removal without nicking Bowman’s layer (as observed with the laser microscope). However, we found significantly inferior results of Epi-Clear PRK compared to alcohol-assisted PRK. Furthermore, after Epi-Clear PRK corneal infiltrates as a new type of postoperative complication were observed.

Role of therapeutic contact lens following Descemet's stripping automated endothelial keratoplasty: A randomized control trial.

Purpose:Therapeutic contact lenses (TCL) are known to help in epithelial healing and decreasing pain after various corneal surgeries. However, literature lacks any data describing their use following Descemet's stripping automated endothelial keratoplasty (DSAEK) where intraoperative epithelial debridement is commonly performed. Here we study the efficacy and safety of TCL in patients undergoing DSAEK.Methods:In this prospective, randomized, controlled clinical trial. 40 eyes of 40 patients of pseudophakic bullous keratopathy undergoing DSAEK were enrolled and randomized into two groups, control (no TCL) and test (TCL). Primary outcome was time taken for epithelial healing and secondary outcomes were postoperative pain score, graft attachment, best spectacle-corrected visual acuity, and endothelial cell loss at 3 months.Results:Average time taken for epithelial healing was 3.35 ± 0.49 days in the test group and 4.95 ± 1.05 days in the control group (P < 0.001). Average pain scores in first operative week were significantly lower in the test group as compared to control (P < 0.001). Graft detachment occurred in eight patients in control group and two in test group (P = 0.03). Both rebubbling rates and average endothelial cell loss at 3 months were higher in the control group with P = 0.07 and 0.06 respectively. No contact lens-related adverse effects were noted during the study period.Conclusion:Use of TCL in DSAEK leads to faster epithelial healing and lesser postoperative pain. In addition, it may also contribute to lower rebubbling rates and endothelial cell loss.

Brillouin microscopic depth-dependent analysis of corneal crosslinking performed over or under the LASIK flap.

To determine the impact of corneal crosslinking (CXL) performed over the laser in situ keratomileusis (LASIK) flap using the Standard CXL (S-CXL) protocol or under the flap after flap lift (flap-CXL) on regional corneal stiffness using Brillouin microscopy. University of Southern California Keck School of Medicine, Los Angeles, California, and Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA. Laboratory ex vivo experiment. After epithelium debridement, LASIK flaps were created on intact fresh porcine eyes with a mechanical microkeratome. Then, S-CXL (riboflavin applied to the corneal surface followed by 3 mW/cm ultraviolet exposure with the flap in place for 30 minutes) or flap-CXL (riboflavin applied to the stromal bed after reflecting the flap followed by the same ultraviolet A exposure with the flap replaced) was performed. Depth profile of stiffness variation and averaged elastic modulus of anterior, middle, and posterior stroma were determined by analyzing Brillouin maps. Each eye served as its own control. The study was performed on 24 fresh porcine eyes. S-CXL had maximal stiffening impact in the anterior most corneal stroma within the LASIK flap (8.40 ± 0.04 GHz), whereas flap-CXL had lower maximal stiffening impact (8.22 ± 0.03 GHz) (P < .001) that occurred 249 ± 34 μm under the corneal surface. S-CXL increased longitudinal modulus by 6.69% (anterior), 0.48% (middle), and -0.91% (posterior) as compared with flap-CXL, which increased longitudinal modulus by 3.43% (anterior, P < .001), 1.23% (middle, P < .1), and -0.78% (posterior, P = .68). The S-CXL technique generated significantly greater stiffening effect in the anterior cornea than a modified protocol with riboflavin administration under the flap (flap-CXL). Minimal stiffening occurred in the middle or posterior cornea with either protocol.