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The Cornea
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  • Meta-Analysis of Postoperative Outcome Parameters Comparing Descemet Membrane Endothelial Keratoplasty Versus Descemet Stripping Automated Endothelial Keratoplasty
    imagePurpose: This meta-analysis compares Descemet membrane endothelial keratoplasty (DMEK) with Descemet stripping automated endothelial keratoplasty (DSAEK) to evaluate their strength and weakness profiles. Design: Meta-analysis. Methods: We performed a meta-analysis and searched the peer-reviewed literature in PubMed, Cochrane Library, Web of Science, and Embase following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Prospective and retrospective trials performing and comparing DMEK and DSAEK were included. Effects were calculated as odds ratios or standardized mean differences. Results: A total of 11 studies with a total of 723 eyes (350 DMEK and 373 DSAEK) were included. No significant difference was found regarding the total detachment rate, graft failure, and rejection. One of 340 eyes undergoing DMEK showed total detachment and 5 of 363 eyes undergoing DSAEK showed total detachment (P = 0.28). Six of 280 eyes undergoing DMEK showed graft failure; 1 of 313 eyes undergoing DSAEK developed this complication (P = 0.18). No rejection was observed in 158 eyes undergoing DMEK; 4 cases of rejection occurred in 196 eyes undergoing DSAEK (P = 0.37). No significant difference was found regarding endothelial cell loss (P = 0.48). There was a significantly higher partial detachment rate with DMEK: 88 of 340 eyes undergoing DMEK showed partial detachment; 16 of 363 eyes undergoing DSAEK showed this complication (P < 0.00001). DMEK was superior in best-corrected visual acuity after 6 months (P < 0.001), subjective evaluation of visual acuity (P = 0.001), patient satisfaction (P < 0.001), and was the method preferred by patients (P = 0.001). Conclusions: DMEK and DSAEK have a similar complication profile. However, the superiority in the visual outcome and patient satisfaction makes DMEK the preferred option for most patients.

  • Minimizing Graft Preparation Failure in Descemet Membrane Endothelial Keratoplasty
    imagePurpose: To report the failure rate of 2 graft preparation techniques for Descemet membrane endothelial keratoplasty (DMEK) and to evaluate how to minimize graft preparation failure. Methods: Retrospective, nonrandomized study at an eye bank specialized in graft preparation for lamellar keratoplasty. For 1416 donor corneas, the DMEK graft preparation failure rate was evaluated for 2 different techniques, technique I: ?Standardized traditional technique? (n = 341) and technique II: ?Standardized no-touch technique? (n = 933), and for grafts that were converted from technique II to technique I during preparation (n = 142). Results: The overall failure rate averaged 3.9% (55/1416): 7.0% (24/341) for technique I and 2.9% (31/1075) for technique II (P < 0.05). Tissue preparations which were converted from technique II to technique I failed in 13.4% (19/142), whereas for grafts that were entirely prepared by technique II, the failure rate was only 1.3% (12/933). The endothelial cell density decrease (before compared with after preparation) did not differ for both techniques (1.1% vs. 0.2%, P > 0.05). Conclusions: Various DMEK graft preparation techniques may provide failure rates of <4%. A ?no-touch preparation? approach (technique II) may combine good graft quality (completely intact endothelial cell layer, ie, negligible preparation-induced endothelial cell density decrease) with low risk of dissection failure, leaving the possibility of conversion to ?traditional preparation? (technique I) as a backup method.

  • Standardizing Descemet Membrane Endothelial Keratoplasty Graft Preparation Method in the Eye Bank?Experience of 527 Descemet Membrane Endothelial Keratoplasty Tissues
    imagePurpose: To share the experience and provide a standardized protocol for Descemet membrane endothelial keratoplasty (DMEK) graft preparation. Methods: A retrospective study based on 527 prestripped DMEK tissues that were prepared between 2014 and 2017. The experience of using different instruments and techniques has been described, and a standardized technique for preparing DMEK grafts has been identified. The tissues in general were prepared by superficially tapping the endothelial side with a Moria trephine (9.5 mm diameter). The plane of cleavage was identified using a cleavage hook, and the DMEK graft was deadhered from the trephined site throughout the circumference for ease of excising the graft. The DMEK graft was peeled using either one or multiple quadrant methods depending on the challenges faced during excision. The graft was finally marked with the letter ?F? to identify the orientation during surgery. Data on endothelial cell loss (ECL) and challenging cases were observed, monitored, and recorded during this period. Results: Less than 1 percent trypan blue-positive cells with tissue wastage of <6% was observed during the study period. Our standardized stripping technique has resulted in an overall ECL of 4.6%. Marking Descemet membrane showed 0.5% cell mortality. Conclusions: Standardizing DMEK technique using specific tools and simple techniques would help new surgeons to decide the instruments and improve their tissue preparation skills also in challenging cases such as previous cataract incisions or horseshoe-shaped tears, further reducing ECL or tissue wastage.

  • Multicenter Study of 6-Month Clinical Outcomes After Descemet Membrane Endothelial Keratoplasty
    imagePurpose: To report the 6-month clinical outcomes of a large cohort of Descemet membrane endothelial keratoplasty (DMEK) eyes operated by 55 starting or experienced surgeons. Methods: This is a retrospective, multicenter, interventional, cohort study with a total of 2485 eyes. Best-corrected visual acuity (BCVA), endothelial cell density (ECD) decrease, and intra- and post-operative complications were evaluated. Three groups based on case order were compared: group I (cases 1?24), group II (cases 25?99), and group III (cases ?100). Forty-nine percent of the surgeons were in their learning curve (<25 cases), representing 10.4% of the surgeries. Results: Six months after DMEK, BCVA improved in 90.5% of eyes, remained unchanged in 4.6%, and deteriorated in 4.9% (n = 1936); 75.4% of eyes reached a BCVA of ?20/40 (?0.5), 45.4% ?20/25 (?0.8), and 25.8% ?20/20 (?1.0) (n = 1959) and ECD decreased by 40% (19) (n = 1272, P < 0.05). BCVA and ECD outcomes did not differ between groups I and III (P > 0.05). Intraoperative complications were reported for 9.4% of eyes, whereas graft detachment was the main postoperative complication (27.4%), with lower intra- and post-operative complication rates in group III than group I (P < 0.05). Rebubbling was performed in 20.1% of eyes; 13.8% required secondary keratoplasty within 6 months. Conclusions: DMEK is applicable for surgeons in various settings with good clinical outcomes. After an arbitrary learning curve (<25 cases), virtually all transplant-related complications declined with experience. Notably, surgeons with a higher annual caseload may pass faster through their learning curve than surgeons performing their first surgeries over an extended period.

  • Learning DMEK From YouTube
    Purpose: To evaluate the outcomes of the first cases of Descemet membrane endothelial keratoplasty (DMEK) performed by an anterior segment surgeon, learning the procedure, including graft preparation, primarily from watching YouTube videos. DMEK surgery was not learned during fellowship training; there was no attendance at DMEK courses, no witnessing of live surgery, and no supervision by an experienced DMEK surgeon. All graft tissue was prepared by the surgeon on the day of surgery. Methods: This is a retrospective review of the 3-month postoperative results of the first 40 consecutive cases. The success rate of graft preparation, intraoperative and postoperative complications, spectacle-corrected visual acuity, endothelial cell density, and central corneal thickness were evaluated. Results: Grafts were successfully prepared in all cases with no loss of donor tissue. DMEK surgery was successful in 39 of 40 eyes with the one failure occurring in a vitrectomized eye without an intact iris?lens diaphragm. Spectacle-corrected visual acuity was ?6/6 in 23 of the 25 eyes without comorbidity. Mean endothelial cell density was 1515 (474) cells/mm2. Mean central corneal thickness decreased from 624 (40) ?m preoperatively to 513 (34) ?m postoperatively. Conclusions: Although formal training is desirable, good results can be obtained by an anterior segment surgeon learning DMEK, including graft preparation, without it. DMEK should no longer be considered a procedure with a long learning curve in routine cases.

  • Dark Endothelial Spots After Descemet Membrane Endothelial Keratoplasty May Appear as Recurrent Fuchs Dystrophy or Herald Graft Failure or Rejection
    imagePurpose: To evaluate the clinical significance of dark spots in the donor endothelial cell layer as observed with specular microscopy, in patients who underwent Descemet membrane endothelial keratoplasty (DMEK) for Fuchs endothelial dystrophy (FED). Methods: Specular microscopy images of 83 consecutive eyes up to 7 years after DMEK were retrospectively reviewed in a masked fashion for the presence of dark spots and morphologic changes in the endothelial cell layer and processed for endothelial cell density (ECD) measurements. Results: A normal endothelial cell layer was found in 52/83 eyes (62.7%) (group 0). In the remaining 31/83 eyes, various dark discolorations with or without altered endothelial cell morphology were categorized into 4 groups. Dark spots were classified as artifacts in 10/83 (12.0%) eyes (group I) and as ?superimposed? dots in 10/83 (12.0%) eyes (group II), that is, optical irregularities slightly anterior to a healthy endothelial cell layer. In 11/83 (13.3%) eyes, endothelial stress was characterized by dark grayish discolorations and/or nuclear activation (group III). Most of the latter eyes also had a significant ECD decrease; 3 of these eyes later developed secondary graft failure, of which one was preceded by allograft rejection. None of the eyes showed recurrent guttae typical for FED (group IV). Conclusions: Dark endothelial spots after DMEK for FED may not represent a recurrent disease, but tissue irregularities just anterior to the graft. However, if associated with changes in endothelial cell morphology, nuclear activation and/or ECD decrease, dark discolorations may reflect ?cellular stress? heralding secondary graft failure or (subclinical) allograft rejection.

  • Meibomian Gland Dysfunction Associated With Periocular Radiotherapy
    imagePurpose: To investigate the influence of periocular radiotherapy on meibomian glands. Methods: We evaluated 28 patients (40 eyes) who received radiotherapy (RT group) for conjunctival or orbital lymphoma and 30 age-matched control subjects (60 eyes). Subjects underwent slit-lamp examination of the eyelids, Schirmer test, meibography, and evaluation of tear film breakup time (TBUT), Ocular Surface Disease Index (OSDI) scores, meibomian glands evaluation (meiboscore, meibum expressibility, and lid margin abnormality scores), and tear film lipid layer thickness using an ocular surface interferometer. These parameters were compared between subjects in the RT and control groups. Results: Meiboscores as well as meibum expressibility and OSDI scores in the RT group were significantly higher compared with those in the control group (1.6 0.9 vs. 0.4 0.6, 1.6 1.0 vs. 0.2 0.4, and 48.1 21.4 vs. 6.2 4.4, respectively, P < 0.001, all), whereas the Schirmer value (9.2 5.1 vs. 12.3 5.2, P = 0.004), TBUT (4.2 2.5 vs. 6.4 2.6, P = 0.001), and lipid layer thickness (61.0 29.3 vs. 85.2 20.0, P < 0.001) in the RT group were lower compared with those in the control group. The percentage of meibomian gland dropout was significantly correlated with age (P = 0.025) and total radiation dose (P = 0.012), regardless of the target location of irradiation. Even low-dose irradiated eyes (<30 Gy) exhibited significantly higher meiboscores (P < 0.001) and shorter TBUT (P = 0.005) compared with control eyes. Conclusions: Eyes that received periocular radiotherapy exhibited relatively high tear film instability induced by meibomian gland dysfunction, contributing to the high severity of dry eye symptoms.

  • Conventional Corneal Collagen Cross-Linking Versus Transepithelial Diluted Alcohol and Iontophoresis-Assisted Corneal Cross-Linking in Progressive Keratoconus
    imagePurpose: To compare clinical outcomes of conventional corneal cross-linking (C-CXL) and diluted alcohol and iontophoresis-assisted corneal cross-linking (DAI-CXL) for the treatment of progressive keratoconus (KC). Methods: Ninety-three eyes of 80 patients with KC were treated by C-CXL (n = 47) or DAI-CXL (n = 46). Visual acuity, keratometry, KC indexes, pachymetry, and aberrations were recorded before treatment and 1, 3, 6, and 12 months after treatment. The demarcation line was assessed 1 month after treatment. Results: A significant improvement in visual acuity was observed at month 3 and month 6 after DAI-CXL and C-CXL, respectively. A significant decrease in maximum keratometry was observed in both groups at month 6. The front symmetry index significantly improved in both groups after 6 months, whereas the Baiocchi Calossi Versaci index significantly improved only after DAI-CXL at month 12 (P = 0.01). Average keratometry and other KC indexes were stable during 12 months of follow-up. Central corneal thickness decreased by 28.6 and 40.2 ?m after DAI-CXL and C-CXL at month 1, respectively (P < 0.01), and it reached baseline at the 12th month (P = 0.14) only in the DAI-CXL group. Higher-order aberrations, coma, and spherical aberration significantly worsened at month 1 (P < 0.01) only after C-CXL; however, they improved significantly at month 12 compared with baseline (P < 0.05) in both groups. The demarcation line was visible in all cases at month 1 at a mean depth of 302 56 ?m and 311 57 ?m after DAI-CXL and C-CXL, respectively (P = 0.7). Conclusions: The DAI-CXL protocol seems as effective as the C-CXL protocol in halting KC progression after 1 year of follow-up.

  • Corneal Tomographic Changes After UV Cross-Linking for Corneal Ectasia (1-Year Results)
    imagePurpose: To evaluate changes in maximum keratometry (Kmax), corneal higher-order aberrations (HOAs), and densitometry (backscattered light) up to 1 year after UV cross-linking and their possible relation with changes in the visual outcome. Methods: Retrospective cohort study on 18 eyes of 16 patients, who underwent UV cross-linking after the Dresden protocol for progressive keratoconus or ectasia after laser-assisted in situ keratomileusis. Corrected distance visual acuity (CDVA), Scheimpflug-based corneal tomography, mean image brightness (corneal densitometry) from the anterior 120 ?m of the midcornea, and posterior 60 ?m of the central 6 mm of the cornea, and HOAs were evaluated. Results: Kmax at 1 month (59.7 6.0D) after UV cross-linking resembled preoperative Kmax (59.3 6.4D, P = 0.368), decreased until 3 months postoperatively (58.3 6.3D, P = 0.002), and stabilized thereafter (P > 0.227). All postoperative corneal densitometry values were higher than preoperative values in all measured depths (P < 0.05). One-month anterior and total corneal HOAs (4.28 1.64 ?m and 3.87 1.62 ?m, respectively) resembled preoperative values (4.10 1.70 ?m and 3.67 1.62 ?m, respectively; P > 0.221) and then decreased until 12 months postoperatively (3.86 1.84 ?m and 3.40 1.80 ?m, respectively; P < 0.005). Thinnest point thickness decreased from before (442 25 ?m) to 3 months postoperatively (427 25 ?m, P < 0.001), with no difference at 12 months postoperatively compared with preoperative values (437 29 ?m, P = 0.149). CDVA and endothelial cell density remained unchanged (P > 0.345 and P > 0.257, respectively). No relations were found between CDVA and the evaluated parameters (P > 0.05). Conclusions: One year after UV cross-linking, the observation of stable CDVA and thinnest point thickness, together with reduced Kmax suggests no ectasia progression within the study period in these cases. Although HOAs showed a trend toward improvement, corneal densitometry remained elevated.

  • Accelerated Epi-On Versus Standard Epi-Off Corneal Collagen Cross-Linking for Progressive Keratoconus in Pediatric Patients
    imagePurpose: To evaluate and compare the effectiveness and safety of accelerated transepithelial (A-epi-on) corneal collagen cross-linking (CXL) with standard CXL (epi-off) for children with progressive keratoconus. Methods: Prospective, cohort study including 61 eyes of 51 patients younger than 18 years with progressive keratoconus at Oftalmosalud Instituto de Ojos, Lima, Peru. A-epi-on CXL was performed for 36 eyes using 30 minutes of impregnation (0.25% riboflavin, 1.0% phosphate hydroxypropyl methylcellulose, 0.007% benzalkonium chloride) and 5 minutes of irradiation (18 mW/cm2). Epi-off CXL was performed for 25 eyes using 30 minutes of impregnation (riboflavin 0.1% solution plus 20% dextran 500) and 30 minutes of irradiation (3 mW/cm2). Scheimpflug imaging parameters were evaluated preoperatively and at 6 and 12 months postoperatively. Results: Mean uncorrected visual acuity improvement was 0.12 logarithm of the minimum angle of resolution (logMAR) for both groups (P = 0.09 for A-epi-on and P = 0.16 for Epi-off). Mean improvements in the best-corrected visual acuity were 0.09 logMAR (P = 0.05) and 0.06 logMAR (P = 0.05) at 12 months postoperatively for the A-epi-on group and the epi-off group, respectively. Mean maximum keratometry changes were +0.1 D (P = 0.62) and ?0.94 D (P = 0.11) for the A-epi-on group and the epi-off group, respectively, at 12 months postoperatively. There were no significant differences between groups regarding changes in pachymetry and posterior elevation values (P > 0.05). Keratoconus progression was observed in 5.6% and 12% of eyes in the A-epi-on group and the epi-off group, respectively. Conclusions: Accelerated epi-on CXL and standard epi-off CXL are safe and effective for stopping the progression of keratoconus at 12 months postoperatively.

  • Lamina Cribrosa Thickness in Patients With Keratoconus
    imagePurpose: To evaluate the thickness and depth of lamina cribrosa (LC) in the optic nerve head region of the eyes in patients with nonglaucomatous keratoconus and to compare the thickness and depth with those of age-matched controls. Methods: This was a cross-sectional, observational study comprising 45 patients with keratoconus and 56 healthy subjects. Analysis of LC imaging was performed using spectral domain optical coherence tomography. Data collected included spherical equivalent, central corneal thickness, axial length, intraocular pressure, and keratometry. Results: Eyes with keratoconus had significantly thinner LC (174.9 11.4 vs. 249.1 4.9 ?m, P < 0.001) compared with control group eyes. There was no statistically significant difference in the depth of LC between the keratoconus and control groups (P = 0.3). Multivariable analysis, controlled for age and sex, showed that the thickness of LC significantly correlated with central corneal thickness (P < 0.001). This association persisted (P < 0.001) after controlling for intraocular pressure in addition to age and sex. There was no significant correlation with other factors, including the spherical equivalent (P = 0.93) and keratometry (P = 0.46). Conclusions: The results of this study showed that optical coherence tomography measurement of LC revealed thinner LC for patients with keratoconus compared with healthy controls. The structural properties of the cornea may be related to the optic nerve.

  • Comparison of the Center and Flex-Center Methods of Corneal Endothelial Cell Analysis in the Presence of Guttae
    imagePurpose: To compare endothelial cell analysis by the center and flex-center methods in corneas with guttae of differing severity and to determine the minimum countable cell number for using only the flex-center method. Methods: Forty-seven eyes with corneal guttae and 50 age-matched normal controls were enrolled in the study. Three images were captured in each central cornea with the noncontact specular microscope. Endothelial cell density (ECD), coefficient of variation (CV), and percentage of hexagonal cells (HEX) were analyzed by trained graders, using both center and flex-center methods. Results: Consistent ECD and HEX values were obtained in normal eyes by both methods (P > 0.05). In corneas with guttae, ECD values obtained by the center method were 2.4% higher than those obtained with the flex-center method (P < 0.001). ECD values derived by both methods disagreed only when <30 cells were identified or <20 cells were analyzed. CV values obtained by the center method were 17.1% (P < 0.001) lower than those obtained by the flex-center method. HEX values obtained with both methods (P > 0.05) agreed. Regardless of guttae density, the ECD, CV, and HEX values of 3 images of each eye were in agreement (P > 0.05). Conclusions: In corneas with guttae, both center and flex-center methods can reliably determine ECD. Although current practice recommends the center method when at least 100 cells can be counted, our study suggests that the center method can provide a reliable ECD value when there are ?30 contiguous countable cells in a central cornea endothelial image. The flex-center method is recommended when <30 contiguous cells are identified.

  • Comparison of Oral Voriconazole Versus Oral Ketoconazole as an Adjunct to Topical Natamycin in Severe Fungal Keratitis: A Randomized Controlled Trial
    imagePurpose: To compare the efficacy of oral voriconazole (VCZ) with oral ketoconazole (KCZ) as an adjunct to topical natamycin in severe fungal keratitis. Methods: Fifty eyes of 50 patients with proven severe fungal keratitis, (>5 mm size, involving >4 mm central cornea and >50% stromal depth), smear, and/or culture positive were randomized to receive either oral VCZ (n = 25) or oral KCZ (n = 25) 200 mg twice a day. Both groups received topical natamycin along with oral medication. The primary outcome measure was best spectacle-corrected visual acuity (BSCVA) at 3 months of follow-up. Secondary outcomes were the percentage of healed cases and scar size. Results: The mean BSCVA after treatment was 1.3 0.35 logarithm of minimum angle of resolution units in the VCZ group and 1.6 0.39 logarithm of minimum angle of resolution units in the KCZ group [P = 0.004, 95% confidence interval (CI), ?0.10 to 0.54]. The final mean scar size was smaller for oral VCZ than for oral KCZ (P = 0.04, 95% CI, ?0.01 to 0.93 mm). The percentage of cases healed were 80% and 72% in VCZ and KCZ groups, respectively (P = 0.51, 95% CI, ?0.15 to 0.31). The ratio of tear film to serum concentration of oral VCZ was better than oral KCZ at days 14 (P = 0.002) and 21 (P = 0.006). Conclusions: Although the duration and percentage of healing was similar in both groups, oral VCZ attained a significantly better tear film concentration with a smaller scar size and better BSCVA compared with oral KCZ. Thus, oral VCZ may be preferred over oral KCZ in severe fungal keratitis.

  • Bacterial Keratitis in Toronto: A 16-Year Review of the Microorganisms Isolated and the Resistance Patterns Observed
    imagePurpose: To review the incidence, distribution, current trends, and resistance patterns of bacterial keratitis isolates in Toronto over the past 16 years. Methods: Microbiology records of suspected bacterial keratitis that underwent a diagnostic corneal scraping and cultures from January 1, 2000, through December 31, 2015, were retrospectively reviewed. The distribution of the main isolated pathogens and in vitro laboratory minimum inhibitory concentration testing results were used to identify resistance patterns. Results: A total of 2330 corneal scrapings were taken over 16 years. A pathogen was recovered in 1335 samples (57.3%), with bacterial keratitis accounting for 1189 of the positive cultures (86.0% of all isolates). The total number of gram-positive and gram-negative isolates was 963 and 324, respectively. Coagulase-negative Staphylococcus and Pseudomonas aeruginosa were the most common gram-positive and gram-negative bacteria isolates, respectively. A decreasing trend in the number of isolates in gram-positive bacteria (P = 0.01), specifically among Staphylococcus aureus (P < 0.0001) and Streptococcus species (P = 0.005), was identified. When analyzing the susceptibilities of gram-positive and gram-negative isolates, an increasing trend in antibiotic resistance was observed in erythromycin (P = 0.018), ceftazidime (P = 0.046), and piperacillin/tazobactam (P = 0.005). The susceptibility of tested gram-positive microorganisms to vancomycin was 99.6%. Conclusions: There has been a decreasing trend in the number of isolates in gram-positive microorganisms over the past 16 years. An increasing trend in resistance for various antibiotics against gram-negative and gram-positive isolates was identified. High susceptibility to vancomycin reinforced the empirical use of fortified tobramycin and vancomycin in the initial management of severe bacterial keratitis.

  • Descemet Membrane Thickening as a Sign for the Diagnosis of Corneal Graft Rejection: An Ex Vivo Study
    imagePurpose: To disclose, using an ex vivo study, the histopathological mechanism behind in vivo thickening of the endothelium/Descemet membrane complex (En/DM) observed in rejected corneal grafts (RCGs). Methods: Descemet membrane (DM), endothelium, and retrocorneal membranes make up the total En/DM thickness. These layers are not differentiable by high-definition optical coherence tomography; therefore, the source of thickening is unclear from an in vivo perspective. A retrospective ex vivo study (from September 2015 to December 2015) was conducted to measure the thicknesses of DM, endothelium, and retrocorneal membrane in 54 corneal specimens (31 RCGs and 23 controls) using light microscopy. Controls were globes with posterior melanoma without corneal involvement. Results: There were 54 corneas examined ex vivo with mean age 58.1 12.2 in controls and 51.7 27.9 years in RCGs. The ex vivo study uncovered the histopathological mechanism of En/DM thickening to be secondary to significant thickening (P < 0.001) of DM (6.5 2.4 ?m) in RCGs compared with controls (3.9 1.5 ?m). Conclusions: Our ex vivo study shows that DM is responsible for thickening of the En/DM in RCGs observed in vivo by high-definition optical coherence tomography and not the endothelium or retrocorneal membrane.

  • Effect of Multipurpose Solution Combined With Autophagy Inhibitors on Adhesion of Acanthamoeba trophozoites to Silicone Hydrogel Contact Lenses
    imagePurpose: The aim of the study was to evaluate the effect of multipurpose contact lens (CL) solution (MPS) combined with autophagy inhibitors on the adhesion properties of Acanthamoeba castellanii (AC) trophozoites to silicone hydrogel CLs. Methods: AC trophozoites were inoculated onto discs trimmed from a silicone hydrogel CL with plasma surface treatment. After 18 hours, the number of adherent AC trophozoites on the CL treated with MPS was counted under phase-contrast microscopy. We analyzed the efficacy of MPS combined with autophagy inhibitors, 3-methyladenine (0.1, 1, and 5 mM) and chloroquine (10, 100 ?M, and 1 mM), on Acanthamoeba adhesion by electron microscopy. Results: Adhesion of AC trophozoites to the CL treated with MPS (average number of trophozoites adhered to the CL: 61.2 8.1) was significantly lower compared with that of the CL treated without MPS (83.8 10.2) (P = 0.027). In MPS application, the number of adhered AC trophozoites treated with 3-methyladenine [8.2 2.5 for 5 mM (P = 0.008)] or chloroquine [19.4 7.6 for 100 ?M (P = 0.038) and 5.3 1.9 for 1 mM (P = 0.001)] was significantly reduced compared with the sample without autophagy inhibitors. However, the number of adherent AC trophozoites was not significantly reduced in less than 5 mM in 3-methyladenine [50.4 5.1 for 0.1 mM (P = 0.084) and 43.1 5.0 for 1 mM (P = 0.079)] and 100 ?M in chloroquine [40.6 13.5 for 10 ?M (P = 0.075)]. 3-methyladenine induced blebby structures or disrupted the membranes of AC trophozoites. AC trophozoites treated with chloroquine showed undigested organelles in the cytoplasm of Acanthamoeba cells. Conclusions: MPS combined with 3-methyladenine or chloroquine reduced the adhesion rate of AC trophozoites rather than MPS containing only polyhexamethylene biguanide. Appropriate concentrations of autophagy inhibitors, 3-methyladenine and chloroquine, added to commercial MPS should be considered to decrease the clinical rate of Acanthamoeba keratitis.

  • Promotion of Corneal Epithelial Wound Healing in Diabetic Rats by the Fibronectin-Derived Peptide PHSRN
    imagePurpose: Topical application of the fibronectin-derived peptide PHSRN facilitates corneal epithelial wound healing in healthy animals and in patients with nonhealing epithelial defects. We have now examined the effect of PHSRN eye drops on the healing of corneal epithelial wounds in diabetic rats. Methods: Wistar rats were injected intraperitoneally with streptozotocin to induce diabetes or with a vehicle as a control. Four weeks after confirmation of the corresponding presence or absence of glycosuria, a 3-mm-diameter portion of the corneal epithelium of the right eye was excised and eye drops containing PHSRN (200 ?M) or phosphate-buffered saline (PBS) vehicle were administered to the injured eye every 6 hours. Results: The area of the epithelial defect did not differ significantly among the 4 experimental groups (diabetic or nondiabetic rats treated with PHSRN or vehicle) at 12 hours after wounding. At 18 hours, however, the area of the defect in diabetic rats treated with PHSRN (0.50 0.34 mm2) was significantly (P < 0.05) smaller than that in diabetic rats treated with PBS (1.06 0.42 mm2) and was similar to that in nondiabetic rats treated with PBS (0.60 0.23 mm2). The decrease in the size of the epithelial defect in diabetic rats treated with PHSRN was also found to be dependent on the dose of the peptide. Conclusions: Administration of PHSRN significantly facilitated healing of corneal epithelial wounds in diabetic rats, which suggests that PHSRN eye drops warrant further investigation as a treatment option for patients with diabetic keratopathy.

  • Aberrant Patterns of Key Epithelial Basement Membrane Components in Keratoconus
    imagePurpose: In the cornea, the epithelial basement membrane (BM) plays an important role in maintaining corneal integrity and homeostasis. Aberrations in this vital structure are associated with several corneal pathologies including keratoconus. The aim of this study was to investigate the expression of key structural components of the epithelial BM in keratoconic corneas and to identify and describe any aberrant patterns. Methods: Immunohistochemical labeling of key BM components including fibronectin, laminin, and type IV and VII collagen was performed in healthy and keratoconic corneas. Results: Clear changes in the BM components in the keratoconic corneas were seen with the key structural components either being absent or forming a discontinuous pattern. Another aberrant pattern, the expression of BM proteins, particularly fibronectin, laminin, and type IV collagen, in the anterior stroma of keratoconic corneas was also observed. Conclusions: These results indicate the activation of keratocytes into the fibroblast and myofibroblast wound phenotypes and the potential source of corneal scarring commonly observed in keratoconic corneas. Our data also support the hypothesis of dysregulated collagen synthesis and breakdown in the keratoconic cornea, in particular, the BM, and suggest a role for the BM in initiation and progression of keratoconus.

  • Adjuvant Stromal Amphotericin B Injection for Late-Onset DMEK Infection
    imagePurpose: To report the successful medical management of a late-onset Descemet membrane endothelial keratoplasty (DMEK)-related interface infection. Methods: A case of DMEK endothelial keratoplasty-related infection treated with intrastromal antifungal injection was identified. The following information was collected: demographic data, surgical indications, donor rim cultures, donor mate outcomes, clinical course, diagnostic tests, and clinical outcome. Results: A DMEK patient developed a single infiltrate approximately 1 month after uncomplicated DMEK. Donor rim culture was positive for Candida glabrata but no prophylactic treatment was initiated. Anterior segment optical coherence tomography confirmed the location of the infiltrate, and the patient was treated with oral fluconazole and an intrastromal injection of amphotericin B with an inadvertent, but negligible, intracameral volume of the same drug. The lesion significantly regressed on examination 2 days later with complete involution and excellent visual acuity to date. Conclusions: Medical therapy, including systemic and intrastromal application, is a viable initial treatment option for late-onset, presumed yeast interface keratitis in patients who have undergone DMEK.

  • Descemet Membrane Endothelial Keratoplasty Patch for Persistent Corneal Hydrops
    imagePurpose: To report successful management of a case of persistent keratoconus-related hydrops with a Descemet membrane endothelial keratoplasty (DMEK) patch graft. Methods: A case of corneal hydrops persisting for 7 months treated with DMEK was identified. The following information was collected: demographic data, surgical indications, clinical course, diagnostic tests, and clinical outcome. Results: A 55-year-old patient with an established diagnosis of keratoconus was followed for 7 months without improvement in his acute corneal hydrops. Because of excellent vision and central corneal clarity, the patient was treated with a 5-mm DMEK covering the Descemet membrane tear, developing cataract secondary to the procedure, but with resolution of his corneal hydrops. An uncorrected visual acuity of 20/25 was achieved after uncomplicated cataract extraction. Conclusions: DMEK, although technically challenging, can be considered for patients with persistent hydrops with preservation of corneal clarity and contour in areas of the uninvolved cornea.



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