Cornea

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Kheirkhah A, Coco G, Satitpitakul V, Dana R. Subtarsal Fibrosis Is Associated With Ocular Surface Epitheliopathy in Graft-Versus-Host Disease. Am J Ophthalmol 2018;189:102-110.Abstract
PURPOSE: To evaluate occurrence of subtarsal fibrosis in patients with graft-vs-host disease (GVHD) and to determine its association with ocular surface epitheliopathy. DESIGN: Cross-sectional study. METHODS: We enrolled 40 patients with moderate or severe dry eye disease, including 20 patients with chronic ocular GVHD and 20 patients without (as the control group). All patients had a comprehensive ophthalmic assessment including evaluation for subtarsal fibrosis, corneal and conjunctival staining, tear break-up time (TBUT), and Schirmer test. Furthermore, meibomian gland drop-out area and densities of epithelial and stromal immune cells were measured using meibography and in vivo confocal microscopy, respectively. RESULTS: Subtarsal fibrosis was not seen in any eye of the non-GVHD group. However, 16 eyes (40%) of 10 patients (50%) in the GVHD group had subtarsal fibrosis (P < .001) with an average involvement of 28.9% ± 13.7% of the tarsal area. Fibrosis was more frequent in the upper lids (35%) than in the lower lids (5%). Regression analyses showed that corneal fluorescein staining was significantly associated with the extent of fibrosis (P < .001, β = 0.14) and TBUT (P < .001, β = -0.53) but not with other clinical or imaging parameters. Conjunctival lissamine green staining also had a statistically significant association with the extent of fibrosis (P = .04, β = 0.12) but not other clinical or imaging parameters. Eyes with subtarsal fibrosis had a more severe ocular surface epitheliopathy compared with eyes without fibrosis. CONCLUSIONS: Subtarsal fibrosis is present in a significant percentage of patients with chronic ocular GVHD, likely contributing to the ocular surface damage in these patients.
Kheirkhah A, Dohlman TH, Amparo F, Arnoldner MA, Jamali A, Hamrah P, Dana R. Effects of corneal nerve density on the response to treatment in dry eye disease. Ophthalmology 2015;122(4):662-8.Abstract

PURPOSE: To evaluate whether levels of corneal subbasal nerve fiber length (SNFL) in dry eye disease (DED) could prognosticate the level of improvement in signs and symptoms after treatment. DESIGN: Phase IV, double-masked, randomized clinical trial. PARTICIPANTS: Sixty patients with meibomian gland dysfunction-associated DED and 27 age-matched controls. METHODS: Patients with DED were randomized to receive topical artificial tears, loteprednol etabonate 0.5%, or loteprednol etabonate 0.5%/tobramycin 0.3% twice daily for 4 weeks. At baseline, in vivo confocal microscopy of central cornea was performed in both eyes. Patients with DED were divided into 2 subgroups: those with low baseline SNFL and those with near-normal baseline SNFL for this purpose (the cutoff point: the mean SNFL in controls minus 2 standard deviations). Clinical signs and symptoms at baseline and after 4 weeks of treatment were compared between the subgroups with low and near-normal SNFL for all therapeutic groups. MAIN OUTCOME MEASURES: Symptom questionnaires, corneal fluorescein staining (CFS), conjunctival staining with lissamine green, tear break-up time, Schirmer's test, and SNFL. RESULTS: In patients with DED, baseline SNFL (17.06±5.78 mm/mm(2)) was significantly lower than in controls (23.68±3.42 mm/mm(2), P = 0.001). In the artificial tear and loteprednol groups, although no significant improvement in any sign or symptom was noted in patients with low baseline SNFL (<16.84 mm/mm(2)), subjects with near-normal baseline SNFL (≥16.84 mm/mm(2)) showed significant improvement in both symptoms and CFS score (all P < 0.05). In the loteprednol/tobramycin group, no significant change was evident for any sign or symptom in either subgroup of low or near-normal baseline SNFL. CONCLUSIONS: Significant improvements in CFS and patient symptomatology after DED treatment were evident only in the subgroup with near-normal corneal SNFL. Consideration of SNFL may assist in explaining the variability of patients' response to DED therapy.

Kheirkhah A, Satitpitakul V, Hamrah P, Dana R. Patients With Dry Eye Disease and Low Subbasal Nerve Density Are at High Risk for Accelerated Corneal Endothelial Cell Loss. Cornea 2016;Abstract

PURPOSE: To evaluate changes in corneal endothelial cell density over time in patients with dry eye disease (DED) and to correlate endothelial cell loss with corneal subbasal nerve density. METHODS: This retrospective study included 40 eyes of 20 patients with DED. Laser in vivo confocal microscopy had been performed in the central cornea of both eyes at an initial visit and repeated after a mean follow-up of 33.2 ± 10.2 months. The densities of corneal endothelial cells and subbasal nerves were measured in both visits and compared with 13 eyes of 13 normal age-matched controls. RESULTS: At the initial visit, the DED group had lower densities of corneal endothelial cells (2620 ± 386 cells/mm) and subbasal nerves (17.8 ± 7.5 mm/mm) compared with the control group (2861 ± 292 cells/mm and 22.8 ± 3.0 mm/mm, with P = 0.08 and P = 0.01, respectively). At the end of follow-up, although there was no significant change in subbasal nerve density (16.7 ± 7.2 mm/mm, P = 0.43), the mean corneal endothelial cell density significantly decreased to 2465 ± 391 cells/mm (P = 0.01), with a mean corneal endothelial cell loss of 2.1 ± 3.6% per year. The endothelial cell loss showed a statistically significant negative correlation with the initial subbasal nerve density (Rs = -0.55, P = 0.02). CONCLUSIONS: Patients with DED have an accelerated corneal endothelial cell loss compared with that reported in the literature for normal aging. Those with lower subbasal nerve density, in particular, are at a higher risk for endothelial cell loss over time.

Kheirkhah A, Rahimi Darabad R, Cruzat A, Hajrasouliha AR, Witkin D, Wong N, Dana R, Hamrah P. Corneal Epithelial Immune Dendritic Cell Alterations in Subtypes of Dry Eye Disease: A Pilot In Vivo Confocal Microscopic Study. Invest Ophthalmol Vis Sci 2015;56(12):7179-85.Abstract

PURPOSE: To evaluate density and morphology of corneal epithelial immune dendritic cells (DCs) in different subtypes of dry eye disease (DED) using in vivo confocal microscopy (IVCM). METHODS: This retrospective study included 59 eyes of 37 patients with DED and 40 eyes of 20 age-matched healthy controls. Based on clinical tests, eyes with DED were categorized into two subtypes: aqueous-deficient (n = 35) and evaporative (n = 24). For all subjects, images of laser scanning in vivo confocal microscopy (IVCM) of the central cornea were analyzed for DC density and DC morphology (DC size, number of dendrites, and DC field). These DC parameters were compared among all dry eye and control groups. RESULTS: Compared with the controls, patients with DED had significantly higher DC density, larger DC size, higher number of dendrites, and larger DC field (all P < 0.001). Comparison between aqueous-deficient and evaporative subtypes demonstrated that DC density was significantly higher in aqueous-deficient subtype (189.8 ± 36.9 vs. 58.9 ± 9.4 cells/mm2, P = 0.001). However, there were no significant differences in morphologic parameters between DED subtypes. When aqueous-deficient DED with underlying systemic immune disease (Sjögren's syndrome and graft versus host disease) were compared with nonimmune conditions, the immunologic subgroup showed significantly higher DC density, DC size, and number of dendrites (all P < 0.05). CONCLUSIONS: Corneal IVCM demonstrated differential changes in DC density and morphologic DC parameters between subtypes of DED. These changes, which reflect the degree of immune activation and inflammation in DED, can be used for clinical practice and endpoints in clinical trials.

Kheirkhah A, Satitpitakul V, Syed ZA, Müller R, Goyal S, Tu EY, Dana R. Factors Influencing the Diagnostic Accuracy of Laser-Scanning In Vivo Confocal Microscopy for Acanthamoeba Keratitis. Cornea 2018;37(7):818-823.Abstract
PURPOSE: To determine the factors that influence the sensitivity and specificity of laser-scanning in vivo confocal microscopy (IVCM) for diagnosing Acanthamoeba keratitis (AK). METHODS: This retrospective, controlled study included 28 eyes of 27 patients with AK and 34 eyes of 34 patients with bacterial keratitis (as the control group). All patients had undergone corneal imaging with a laser-scanning IVCM (Heidelberg Retina Tomograph 3 with the Rostock Cornea Module). The IVCM images were independently evaluated by 2 experienced and 2 inexperienced masked observers. Sensitivity and specificity of IVCM for diagnosing AK and the effects of various clinical and imaging parameters on the sensitivity were then investigated. RESULTS: Overall, IVCM had average sensitivity and specificity of 69.7% ± 2.5% and 97.1% ± 4.2% for experienced observers and 59.0% ± 7.6% and 92.7% ± 10.4% for inexperienced observers, respectively. However, the sensitivity did not show any significant association with the duration of disease, size of ulcer, depth of involvement, culture results, or cyst morphology. Although interobserver agreement was good (κ = 0.60, P < 0.001) for the experienced observers, it was only at a moderate level (κ = 0.48, P < 0.001) for the inexperienced observers. CONCLUSIONS: IVCM has a moderate sensitivity and a high specificity for diagnosis of AK. Although clinical parameters do not affect this diagnostic accuracy, a higher sensitivity is seen when images are interpreted by experienced observers.
Kheirkhah A, Saboo US, Abud TB, Dohlman TH, Arnoldner MA, Hamrah P, Dana R. Reduced Corneal Endothelial Cell Density inPatients With Dry Eye Disease. Am J Ophthalmol 2015;159(6):1022-1026.e2.Abstract

PURPOSE: To evaluate corneal endothelial cell density (ECD) in patients with dry eye disease (DED) compared to an age-matched control group. DESIGN: Cross-sectional, controlled study. METHODS: This study included 90 eyes of 45 patients with moderate to severe DED (aged 53.7 ± 9.8 years) and 30 eyes of 15 normal controls (aged 50.7 ± 9.8 years). All subjects had a complete ophthalmic evaluation including symptom assessment using the Ocular Surface Disease Index (OSDI) and corneal fluorescein staining. In addition, laser scanning in vivo confocal microscopy was performed to measure the density of the following parameters in the central cornea: endothelial cells, subbasal nerves, and subbasal immune dendritic cells. RESULTS: Corneal ECD was significantly lower in the DED group (2595.8 ± 356.1 cells/mm(2)) than in the control group (2812.7 ± 395.2 cells/mm(2), P = .046). The DED group showed significantly lower corneal subbasal nerve density (17.1 ± 6.9 mm/mm(2)) compared to the control group (24.7 ± 4.4 mm/mm(2), P < .001). Dendritic cell density was significantly higher in the DED group than in the controls (111.7 ± 137.3 vs 32.0 ± 24.4 cells/mm(2), respectively, P = .002). There were statistically significant correlations between corneal ECD and dry eye severity parameters including the OSDI score (rs = -0.26, P = .03), and corneal fluorescein staining (rs = -0.28, P = .008). CONCLUSIONS: There is a significant reduction in corneal ECD in DED that correlates with clinical severity of the disease.

Kheirkhah A, Di Zazzo A, Satitpitakul V, Fernandez M, Magilavy D, Dana R. A Pilot Randomized Trial on Safety and Efficacy of a Novel Topical Combined Inhibitor of Janus Kinase 1/3 and Spleen Tyrosine Kinase for GVHD-Associated Ocular Surface Disease. Cornea 2017;36(7):799-804.Abstract
PURPOSE: Janus kinase (JAK) and spleen tyrosine kinase (SYK) play critical functions in T-cell activation and in inflammation. Because of their antiinflammatory effects, JAK and SYK inhibitors have recently been evaluated in several immunopathogenic disorders. This pilot study was designed to assess the safety and efficacy of a topical combined JAK/SYK inhibitor, R348, ophthalmic solution for treatment of ocular surface disease in graft-versus-host disease (GVHD). METHODS: This phase 2, double-masked, randomized, pilot trial included 30 patients with ocular surface disease due to GVHD who were randomized to receive topical 0.5% R348, 0.2% R348, or vehicle, twice daily for 12 weeks. Before and after treatment, a comprehensive ophthalmic evaluation was performed, which included Ocular Surface Disease Index (OSDI) questionnaire, Ocular Comfort Index questionnaire, corneal fluorescein staining, conjunctival lissamine green staining, and Schirmer test with anesthesia. Changes in these parameters were compared between the 3 groups. RESULTS: The mean decrease in total corneal fluorescein staining at 12 weeks after treatment was higher in the 0.5% R348 group (-6.0 ± 3.9, NEI scoring) compared with the vehicle (-2.1 ± 2.6, P = 0.045) or the 0.2% R348 group (-4.1 ± 3.6, P = 0.34). However, there were no significant differences among the groups in terms of treatment-induced changes in OSDI, Ocular Comfort Index, conjunctival lissamine green staining, or Schirmer scores. R348 eye drops were well tolerated. CONCLUSIONS: This pilot study indicates that 0.5% R348 JAK/SYK inhibitor ophthalmic solution is well tolerated and may have some therapeutic efficacy in treating ocular GVHD. Larger trials are required to derive more definitive data.
Kheirkhah A, Coco G, Satitpitakul V, Pham TT, Dana R. Limbal and Conjunctival Epithelial Thickness in Ocular Graft-Versus-Host Disease. Cornea 2019;38(10):1286-1290.Abstract
PURPOSE: To compare the thickness of the limbal epithelium (LE) and the bulbar conjunctival epithelium (BCE) between patients with dry eye disease (DED) with and without ocular graft-versus-host disease (GVHD). METHODS: This cross-sectional study enrolled 40 patients with moderate to severe DED including 20 with and 20 without chronic ocular GVHD. All patients had a comprehensive clinical ophthalmic assessment. Moreover, the thickness of the LE and BCE in both nasal and temporal regions of both eyes was measured using spectral domain optical coherence tomography. RESULTS: The average LE thickness in all patients with dry eye (GVHD and non-GVHD) was 65.8 ± 11.9 μm temporally and 69.7 ± 11.1 μm nasally (P = 0.02). The average BCE thickness was 55.8 ± 11.4 μm temporally and 60.1 ± 11.0 μm nasally (P = 0.03). There were no statistically significant differences between GVHD and non-GVHD groups in LE thickness (69.6 ± 11.7 vs. 66.1 ± 6.2 μm, respectively, P = 0.31) or BCE thickness (58.9 ± 9.6 vs. 57.3 ± 9.8 μm, respectively, P = 0.82). There was a significant correlation between LE thickness and BCE thickness (P = 0.01, Rs = 0.41). A statistically significant negative correlation was also observed between LE thickness and age (P = 0.002, Rs = -0.35). There were no significant correlations between the thickness of the LE or BCE and other clinical parameters. CONCLUSIONS: No difference exists in the thickness of the ocular surface epithelia between dry eyes with and without ocular GVHD, which would suggest that these epithelial changes may be independent of the underlying etiology and possibly only reflect the disease severity. Furthermore, there are regional variations in the thickness of the ocular surface epithelia in patients with DED.
Kim EC, Toyono T, Berlinicke CA, Zack DJ, Jurkunas U, Usui T, Jun AS. Screening and Characterization of Drugs That Protect Corneal Endothelial Cells Against Unfolded Protein Response and Oxidative Stress. Invest Ophthalmol Vis Sci 2017;58(2):892-900.Abstract

Purpose: To screen for and characterize compounds that protect corneal endothelial cells against unfolded protein response (UPR) and oxidative stress. Methods: Bovine corneal endothelial cells (BCECs) were treated for 48 hours with 640 compounds from a Food and Drug Administration (FDA)-approved drug library and then challenged with thapsigargin or H2O2 to induce UPR or oxidative stress, respectively. Cell viability was measured using the CellTiter-Glo survival assay. Selected "hits" were subjected to further dose-response testing, and their ability to modulate expression of UPR and oxidative stress markers was assessed by RT-PCR, Western blot, and measurement of protein carbonyl and 8-hydroxydeoxyguanosine (8-OHdG) adducts in immortalized human corneal endothelial cells (iHCECs). Results: Forty-one drugs at 20 μM and 55 drugs at 100 μM increased survival of H2O2-challenged cells, and 8 drugs at 20 μM and 2 drugs at 100 μM increased survival of thapsigargin-challenged cells, compared with untreated control cells. Nicergoline, ergothioneine, nimesulide, oxotremorine, and mefenamic acid increased survival of both H2O2- and thapsigargin-challenged cells. Oxotremorine altered DNA damage inducible 3 (CHOP) gene expression, glucose-regulated protein 78 kDa (GRP78) and activating transcription factor 4 (ATF4) protein expression, and protein carbonyl and 8-OHdG levels. Mefenamic acid altered GRP78 protein expression and protein carbonyl and 8-OHdG levels. Conclusions: Oxotremorine and mefenamic acid are potential survival factors for corneal endothelial cells under UPR and oxidative stress. The described assay can be further expanded to screen additional drugs for potential therapeutic effect in corneal endothelial diseases such as Fuchs' endothelial corneal dystrophy.

Kim S, Bispo PJM, Tanner EEL, Mitragotri S, E Silva RN, Gipson I, Chodosh J, Behlau I, Paschalis EI, Gilmore MS, Dohlman CH. The Search for Antifungal Prophylaxis After Artificial Corneal Surgery-An In Vitro Study. Cornea 2020;39(12):1547-1555.Abstract
PURPOSE: To evaluate the antifungal properties of topical antibiotics (already being used successfully to prevent bacterial endophthalmitis) and some promising antiseptics for antifungal prophylaxis in the setting of artificial corneal implantation. METHODS: Several commonly used antibiotics for antimicrobial prophylaxis after artificial corneal implantation, in addition to antiseptics [benzalkonium chloride (BAK), povidone-iodine (PI), and some ionic liquids (ILs)], were tested in vitro against Candida albicans, Fusarium solani, and Aspergillus fumigatus. The time-kill activity was determined. Toxicity was assayed in vitro on human corneal epithelial cultures using trypan blue. Adhesion and tissue invasion experiments were also carried out on porcine corneas and commonly used contact lenses, with or without gamma irradiation, and by analysis with fluorescence microscopy. RESULTS: Polymyxin B (PMB)/trimethoprim/BAK (Polytrim), PMB alone, gatifloxacin with BAK (Zymaxid), and same-concentration BAK alone exhibited antifungal activity in vitro. Moxifloxacin (MOX) or gatifloxacin without BAK-as well as trimethoprim, vancomycin, and chloramphenicol-had no effect. 1% PI and ILs had the highest efficacy/toxicity ratios (>1), and Polytrim was species dependent. Subfungicidal concentrations of Polytrim reduced adhesion of C. albicans to Kontur contact lenses. Gamma-irradiated corneas showed enhanced resistance to fungal invasion. CONCLUSIONS: Of antibiotic preparations already in use for bacterial prophylaxis after KPro surgery, Polytrim is a commonly used antibiotic with antifungal effects mediated by both PMB and BAK and may be sufficient for prophylaxis. PI as a 1% solution seems to be promising as a long-term antifungal agent. Choline-undecanoate IL is effective and virtually nontoxic and warrants further development.
Kim YJ, Payal AR, Daly MK. Effects of tear gases on the eye. Surv Ophthalmol 2016;61(4):434-42.Abstract

Chemical agents that target the eyes have been a popular choice for law enforcement during riots and for military training for nearly a century. The most commonly used agents are chloroacetophenone (formerly sold as Mace), o-chlorobenzylidene malononitrile, and oleoresin capsicum (OC or pepper spray, current ingredient for Mace). Initially, most severe ocular injuries were caused by the explosive force rather than the chemical itself. The development of sprays reduced the mechanical severity of ocular injuries, but resulted in a variety of chemical injuries. The effects on eyes include conjunctival injection, complete corneal epithelial defects, pseudopterygium, corneal neovascularization, persistent conjunctivalization, corneal opacities, and reduced visual acuity. Current management, based on limited human studies, emphasizes decontamination and symptomatic treatment. We review the literature related to clinical and histopathologic effects of tear gas agents on the eye and their management.

Kitamoto K, Taketani Y, Fujii W, Inamochi A, Toyono T, Miyai T, Yamagami S, Kuroda M, Usui T, Ouchi Y. Generation of mouse model of TGFBI-R124C corneal dystrophy using CRISPR/Cas9-mediated homology-directed repair. Sci Rep 2020;10(1):2000.Abstract
Mutations in transforming growth factor-beta-induced (TGFBI) gene cause clinically distinct types of corneal dystrophies. To delineate the mechanisms driving these dystrophies, we focused on the R124C mutation in TGFBI that causes lattice corneal dystrophy type1 (LCD1) and generated novel transgenic mice harbouring a single amino acid substitution of arginine 124 with cysteine in TGFBI via ssODN-mediated base-pair substitution using CRISPR/Cas9 technology. Eighty percent of homozygous and 9.1% of heterozygous TGFBI-R124C mice developed a corneal opacity at 40 weeks of age. Hematoxylin and eosin and Masson trichrome staining showed eosinophilic deposits in subepithelial corneal stroma that stained negative for Congo-red. Although amyloid deposition was not observed in TGFBI-R124C mice, irregular amorphous deposits were clearly observed via transmission electron microscopy near the basement membrane. Interestingly, we found that the corneal deposition of TGFBI protein (TGFBIp) was significantly increased in homozygous TGFBI-R124C mice, suggesting a pathogenic role for the mutant protein accumulation. Furthermore, as observed in the LCD1 patients, corneal epithelial wound healing was significantly delayed in TGFBI-R124C mice. In conclusion, our novel mouse model of TGFBI-R124C corneal dystrophy reproduces features of the human disease. This mouse model will help delineate the pathogenic mechanisms of human corneal dystrophy.
Kitazawa K, Inotmata T, Shih K, Hughes J-WB, Bozza N, Tomioka Y, Numa K, Yokoi N, Campisi J, Dana R, Sotozono C. Impact of aging on the pathophysiology of dry eye disease: A systematic review and meta-analysis. Ocul Surf 2022;25:108-118.Abstract
PURPOSE: Dry eye disease (DED) is a common age-related ocular surface disease. However, it is unknown how aging influences the ocular surface microenvironment. This systematic review aims to investigate how the aging process changes the ocular surface microenvironment and impacts the development of DED. METHODS: An article search was performed in PubMed, EMBASE, and Web of Science. 44 studies reporting on age-related ocular changes and 14 large epidemiological studies involving the prevalence of DED were identified. 8 out of 14 epidemiological studies were further analyzed with meta-analysis. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines were followed. Study-specific estimates (impact of aging on the prevalence of DED) were combined using one-group meta-analysis in a random-effects model. RESULTS: Meta-analysis revealed the prevalence of DED in the elderly aged 60 years old or older was 5519 of 60107 (9.2%) and the odds ratio of aging compared to younger age was 1.313 (95% confidence interval [CI]; 1.107, 1.557). With increasing age, the integrity of the ocular surface and tear film stability decreased. Various inflammatory cells, including senescent-associated T-cells, infiltrated the ocular surface epithelium, lacrimal gland, and meibomian gland, accompanied by senescence-related changes, including accumulation of 8-OHdG and lipofuscin-like inclusions, increased expression of p53 and apoptosis-related genes, and decreased Ki67 positive cells. CONCLUSIONS: The aging process greatly impacts the ocular surface microenvironment, consequently leading to DED.
Kobashi H, Kamiya K, Shimizu K. Randomized Comparison Between Rebamipide Ophthalmic Suspension and Diquafosol Ophthalmic Solution for Dry Eye After Penetrating Keratoplasty. J Ocul Pharmacol Ther 2017;33(1):13-18.Abstract

PURPOSE: To compare the ocular surfaces of patients treated with rebamipide (REB) ophthalmic suspension or diquafosol (DQS) ophthalmic solution for dry eye syndrome after penetrating keratoplasty (PK). METHODS: A total of 40 eyes of 40 patients who had dry eyes after undergoing PK were enrolled and randomly divided into an REB group and a DQS group. Both REB and DQS groups used each eye drop four times. The tear breakup time (TBUT), corneal fluorescein staining scores, and dry eye-related quality-of-life score (DEQS) were evaluated before treatment, 2 weeks after start of treatment and 4 weeks after start of treatment. RESULTS: We found a significant improvement in TBUT (P < 0.001, Dunnett's test) and fluorescein scores (P < 0.001) 4 weeks after treatment in the REB group. Similar results were obtained in the DQS group (P < 0.001 and P = 0.01, respectively). No significant improvements in DEQS were found 4 weeks after treatment in each group (P = 0.15 and P = 0.63, analysis of variance, respectively). No significant differences were seen in these variables and in the changes between the groups after treatment. CONCLUSIONS: REB and DQS may be effective for the management of dry eye syndrome after PK in terms of ocular surface findings. In our study, effects of REB appear to be equivalent to those of DQS in the patients.

Kobashi H, Rong SS, Ciolino JB. Transepithelial versus epithelium-off corneal crosslinking for corneal ectasia. J Cataract Refract Surg 2018;44(12):1507-1516.Abstract
This review compared the clinical results of transepithelial corneal crosslinking (CXL) to epithelium-off (epi-off) CXL in progressive corneal ectasia using a metaanalysis. The Cochrane databases and Medline were searched for randomized controlled trials (RCTs). Seven RCTs involving 505 eyes that met the eligibility criteria were identified. The epi-off CXL group showed significantly better outcomes in postoperative changes in maximum keratometry (K) during 1-year observation periods. Transepithelial CXL resulted in significantly greater post-treatment central corneal thickness and best spectacle-corrected visual acuity (BSCVA). The presence of a postoperative demarcation line was significantly more frequent after epi-off CXL than that after transepithelial CXL. No statistically significant difference was found between other parameters. Although patients in the transepithelial CXL group demonstrated a greater improvement in BSCVA compared with patients in the epi-off CXL group at the 1 year follow-up, transepithelial CXL had less impact on halting progressive corneal ectasia in terms of maximum K than epi-off CXL.
Kobashi H, Kamiya K, Shimizu K. Dry Eye After Small Incision Lenticule Extraction and Femtosecond Laser-Assisted LASIK: Meta-Analysis. Cornea 2017;36(1):85-91.Abstract

PURPOSE: To compare postoperative ocular surface integrity and innervation between small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). METHODS: The Cochrane Central Register of Controlled Trials, PubMED, and EMBASE were searched for prospective comparative studies. Trials meeting the selection criteria were quality appraised, and the data were extracted by 2 independent authors. The weighted mean differences (WMDs) and 95% confidence intervals (CIs) were used to compare dry eye examinations and corneal subbasal nerve density (SMILE-FS-LASIK). RESULTS: The study covered 5 trials. No significant difference was found in the Schirmer test score between both groups (WMD = -1.91 and 0.27; 95% CI, -5.02 to 1.20 and -0.99 to 1.54; P = 0.23 and 0.67 at 1- and 6-month follow-ups, respectively). Tear breakup time in the SMILE group significantly exceeded that in the FS-LASIK group (WMD = 0.65 and 1.14; 95% CI, 0.20-1.10 and 0.18-2.10; P = 0.004 and 0.02, at 1- and 6-month follow-ups, respectively). Ocular surface disease index scores were significantly better in the SMILE group 6 months postoperatively (WMD = -10.12, 95% CI, -16.07 to -4.18, P = 0.0008). No significant difference was found in tear osmolarity between both groups (WMD = -5.19 and -6.37; 95% CI, -17.15 to 6.76 and -22.74 to 10.00; P = 0.39 and 0.45 at 1- and 6-month follow-ups, respectively). Higher corneal sensitivity was observed in the SMILE group 1 and 6 months postoperatively (WMD = 11.35 and 3.49; 95% CI, 7.29-15.40 and 1.76-5.21; P < 0.00001 and <0.0001, at 1- and 6-month follow-ups, respectively). Corneal subbasal nerve density was also significantly higher in SMILE-treated eyes than it was in FS-LASIK-treated eyes 1 month postoperatively (WMD = 4.72, 95% CI, 1.10-8.34, P = 0.01). CONCLUSIONS: According to this meta-analysis, the SMILE procedure has fewer negative impacts on the ocular surface and corneal innervation than does FS-LASIK. Furthermore, SMILE shows superiority over FS-LASIK by a exhibiting a lower risk of postoperative dry eye.

Kobashi H, Ciolino JB. Innovative Development of Contact Lenses. Cornea 2018;37 Suppl 1:S94-S98.Abstract
Contact lenses have been a common means of vision correction for more than half a century. Recent developments have raised the possibility that the next few decades will see a considerable broadening of the range of applications for contact lenses, with associated expansions in the number and type of individuals who consider them a valuable option. The novel applications of contact lenses include treatment platforms for myopic progression, biosensors, and ocular drug delivery. Orthokeratology has shown the most consistent treatment for myopia control with the least side effects. Recent work has resulted in commercialization of a device to monitor intraocular pressure for up to 24 hours, and extensive efforts are underway to develop a contact lens sensor capable of continuous glucose tear film monitoring for the management of diabetes. Other studies on drug-eluting contact lenses have focused on increasing the release duration through molecular imprinting, use of vitamin E, and increased drug binding to polymers by sandwiching a poly (lactic-co-glycolic acid) layer in the lens. This review demonstrates the potential for contact lenses to provide novel opportunities for refractive management, diagnosis, and management of diseases.
Kobashi H, Kamiya K, Shimizu K. Impact of Forward and Backward Scattering and Corneal Higher-Order Aberrations on Visual Acuity after Penetrating Keratoplasty. Semin Ophthalmol 2018;:1-9.Abstract
PURPOSE: To assess the relationship of forward and backward scattering and corneal higher-order aberrations (HOAs) with corrected distance visual acuity (CDVA) after penetrating keratoplasty (PK). METHODS: This retrospective study comprised 25 eyes of 25 consecutive patients who underwent PK using the VisuMax femtosecond laser system and age-matched 25 eyes of 25 healthy subjects. We quantitatively assessed objective scattering index (OSI) using the double-pass instrument (OQAS II, Visiometrics), corneal densitometry (CD) and corneal HOAs with the Scheimpflug rotating camera (Pentacam HR, Oculus) 1 year postoperatively. RESULTS: The OSI, CD, and corneal HOAs were significantly larger in the PK group than those in the control group (p ≤ 0.011). We found significant correlations of logMAR CDVA with the OSI (r = 0.477, p = 0.016), and with the anterior, posterior, and total corneal HOAs of the central 4-mm zone (anterior: r = 0.573, p = 0.003, posterior: r = 0.596, p = 0.002, total: r = 0.472, p = 0.017), but no significant association with the CD of the 0-2 mm zone at any layers (anterior: r = 0.236, p = 0.257, center: r = 0.139, p = 0.506, posterior: r = 0.073, p = 0.728, total: r = 0.212, p = 0.308). Similar results were obtained when the analysis was repeated with corneal HOAs of the central 6-mm zone and CDs in 2-6 mm zone. CONCLUSIONS: Our pilot study demonstrated that the postoperative CDVA was significantly correlated with OSI and corneal HOAs, but not with backward scattering in post-PK eyes, suggesting that OSI as well as corneal HOAs plays an essential role in postoperative visual performance after PK.
Kocaba V, Damour O, Auxenfans C, Burillon C. [Limbal stem cell deficiency management. A review]. J Fr Ophtalmol 2016;39(9):791-803.Abstract

Limbal stem cell deficiency is predominantly caused by severe eye burns resulting in a decreased or a complete ablation of the regenerative potential of these stem cells. The inability to reconstruct the corneal epithelium further leads conjunctivalization of the gimbal-epithelial barrier. These abnormalities collectively result in the progressive opacification of the cornea responsible for blindness that is driven by chronic corneal ulceration and neovascularization. The underlying pathology of the cornea affects the homeostasis of the neighboring conjunctiva, eyelids, and tear film. Therefore, the ocular reconstruction to treat limbal stem cell deficiency is quite prolonged and involves a continued treatment plan. The management of limbal stem cell deficiency has undergone a multitude of changes over the past several decades. The understanding of limbal anatomy and physiology, as well as therapeutic advances in the stem cell field have propelled the development of new treatments offering new hope to severely disabled patients. Cultivated limbal epithelial and oral mucosal epithelial transplantations are therefore viable alternatives that could be utilized for the treatment of limbal stem cell deficiency.

Kodati S, Chauhan SK, Chen Y, Dohlman TH, Karimian P, Saban D, Dana R. CCR7 is critical for the induction and maintenance of Th17 immunity in dry eye disease. Invest Ophthalmol Vis Sci 2014;55(9):5871-7.Abstract

PURPOSE: We characterized antigen-presenting cell (APC)-relevant chemokine receptor expression in dry eye disease (DED), and investigated the effect of topical CC chemokine receptor (CCR)-7 blockade specifically on Th17 cell immunity and dry eye disease severity. METHODS: We induced DED in female C57BL/6 mice. Chemokine receptor expression by corneal APCs was characterized using immunohistochemistry. To determine the functional role of CCR7 in DED, mice were treated topically with either anti-CCR7, a control isotype antibody, or left untreated, and clinical disease severity, Th17 responses, and molecular markers of DED were quantified. RESULTS: Frequencies of CD11b(+) cells and their chemokine expression were increased in the cornea of DED mice. Mice treated topically with anti-CCR7 antibody displayed a significant reduction in clinical disease severity and Th17 response compared to the isotype and untreated groups. Topical CCR7 blockade was effective in ameliorating DED in its acute and chronic stages. CONCLUSIONS: Our findings suggest that CCR7-mediated trafficking of APCs drives the induction and maintenance of Th17 immunity in DED and that CCR7 blockade is effective in suppressing the immunopathogenic mechanisms in DED.

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