Effect of Head Trauma-Related Deaths on Corneal Endothelial Cell Loss in Eye Bank Donors

PURPOSE

The purpose of this study was to examine the effect of head trauma-related deaths on corneal endothelial cell density (ECD) in eye bank donors.

METHODS

This is a retrospective study of 287 corneas from donors with causes of death secondary to motor vehicle accident with sustained head trauma (n = 50), gunshot wound to the head (n = 138), fall with sustained head trauma (n = 2), and non-head-related traumatic causes of death (n = 97). Donors older than age 50 years were excluded due to concern for undiagnosed Fuchs endothelial dystrophy as a potential confounder for the cause of endothelial cell loss. Donor characteristics, ECD, and focal endothelial cell loss on specular microscopy were compared between the groups. Donors in the head trauma and nonhead trauma groups were matched by age; there were 42 age-matched donors in both groups.

RESULTS

Age and ECD were negatively correlated (Pearson correlation coefficient = -0.57). Death-to-preservation time was not significantly different between the 2 groups ( P value = 0.59). The mean ECD in the head trauma group was 2859 ± 370 cells/mm 2 and 3041 ± 464 cells/mm 2 in the nonhead trauma group. The head trauma group had a lower ECD (178 ± 70 cells/mm 2 , P value = 0.013). After matching for age, the difference in ECD between the 2 groups was -94 ± 82 cells/mm 2 ( P value = 0.26). The adjusted odds of having focal endothelial cell loss was not statistically significant ( P value = 0.50) between the groups.

CONCLUSIONS

After statistical adjustments, there were no differences between the head trauma and nonhead trauma groups.

National Access to EyeSi Simulation: A Comparative Study Among U.S. Ophthalmology Residency Programs

Purpose  The aim of this study was to evaluate regional disparities in access to EyeSi surgical simulation training among U.S. ophthalmology residency programs. Methods  Access to EyeSi simulation was determined from sales data (2021) provided by VRMagic. Key demographic metrics of the primary counties of U.S. residency training programs were retrieved from the U.S. Census Bureau Database (2019) and PolicyMap (2021). Demographic metrics, Veterans Affairs (VA) hospital affiliation, and Doximity residency program ranking (2021) were compared using the Mann-Whitney U test and Fisher's exact test. Results  A total of 124 residency training programs across 95 U.S. counties were included. Regional density (number of EyeSi simulators/million people) was calculated; the west had a significantly lower density when compared with the northeast (NE), south, and midwest (0.4 vs 1.0, 1.3, 1.1, respectively). In the NE, there was a significantly lower population of Blacks ( p  = 0.01), Hispanics ( p  = 0.028), and Native Americans ( p  = 0.008) residing in counties with access to EyeSi, compared with counties without EyeSi access. Programs with EyeSi access ( N  = 95) had a median Doximity ranking of 52.5, whereas programs without EyeSi access ( N  = 35) had a lower median ranking of 94 ( p  < 0.001). Conclusion  Our analysis demonstrates significant disparities in access to EyeSi simulation training in the United States that could disproportionately impact minority communities. Access to an EyeSi simulator was associated with higher residency ranking independent of VA affiliation.

Changes in Rat Scleral Collagen Structure Induced by UVA-Riboflavin Crosslinking at Various Tissue Depths in Whole Globe Versus Scleral Patch

Purpose

To investigate structural changes in scleral collagen fibers at various tissue depths before and after photosensitized crosslinking (CXL) both isolated scleral patch versus whole globe using second-harmonic generation (SHG) imaging.

Methods

Scleral tissues were harvested from Sprague-Dawley rats and separated into three groups: untreated sclera (control), full-thickness scleral patch for CXL (Free Scleral CXL group), and sclera in intact globe for CXL (Globe CXL group). The CXL groups were soaked in 0.1% riboflavin and irradiated with 365 nm ultraviolet-A light (power, 0.45 mW/cm2) for 30 minutes. SHG images were acquired every 5 µm between 10 and 60 µm from the outer scleral surface. Collagen fiber waviness was calculated as the ratio of the total length of a traced fiber and the length of a straight path between the fiber ends.

Results

In the Free Scleral CXL group, collagen waviness was significantly increased compared to the control group at 35 to 50 µm (P < 0.05). In the Globe CXL group, collagen waviness was decreased compared to control at all depths with statistical significance (P < 0.05) achieved from 10 to 45 µm.

Conclusions

Depending upon its initial state (i.e., free scleral patch versus mechanically loaded intact globe under pressure), collagen may experience different structural changes after CXL. In addition, the extent of the CXL effects may vary at different depths away from the surface.

Translational Relevance

Understanding the CXL effects on collagen structure may be important in optimizing the scleral crosslinking protocol for future clinical applications such as preventing myopic progression.

The Cost-Effectiveness of a Telemedicine Screening Program for Diabetic Retinopathy in New York City

Background

A telemedicine screening initiative was implemented by the Montefiore Health System to improve access to eyecare for a multi-ethnic, at-risk population of diabetic patients in a largely underserved urban community in the Bronx, New York. This retrospective, cross-sectional analysis evaluates the societal benefit and financial sustainability of this program by analyzing both cost and revenue generation based on current standard Medicare reimbursement rates.

Methods

Non-mydriatic fundus cameras were placed in collaboration with a vendor in eight outpatient primary care sites throughout the Montefiore Health Care System, and data was collected between June 2014 and July 2016. Fundus photos were electronically transmitted to a central reading center to be systematically reviewed and coded by faculty ophthalmologists, and patients were subsequently scheduled for ophthalmic evaluation based upon a predetermined treatment algorithm. A retrospective chart review of 2251 patients was performed utilizing our electronic medical record system (Epic Systems, Verona WI). Revenue was projected utilizing standard Medicare rates for our region while societal benefit was calculated using quality adjusted life years (QALY).

Results

Of the 2251 patient charts reviewed, 791 patients (35.1%) were seen by Montefiore ophthalmologists within a year of the original screening date. Estimated revenue generated by these visits was $276,800, with the majority from the treatment of retinal disease ($208,535), and the remainder from other ophthalmic conditions detected in the fundus photos ($68,265). There was a societal benefit of 14.66 quality adjusted life years (QALYs) with an estimated value of $35,471/QALY.

Conclusion

This telemedicine initiative was successful in identifying many patients with diabetic retinopathy and other ophthalmic conditions who may otherwise not have been formally evaluated. Our analysis demonstrates the program to generate a downstream revenue of nearly $280K with a cost benefit below <50% of the threshold of $100,000/QALY, and therefore cost-effective in marginalized communities.

What should be the Earliest Age for Clinical Trials of Corneal Cross Linking for Keratoconus?

Keratoconus is often diagnosed in the second or third decade of life, with a younger mean age at diagnosis, in patients of Middle Eastern and Asian descent.1 Patients with severe forms of keratoconus present at a younger age (usually in the second decade of life), and these patients have more rapid progression of the disease. Pediatric keratoconus is generally attributed to disease manifesting in patients less than 18 years of age. However, studies that looked at progression in different age groups used varying age criteria. 

Moxifloxacin releasing intraocular implant based on a cross-linked hyaluronic acid membrane

Intraocular antibiotic delivery is an important technique to prevent bacterial infection after ophthalmic surgery, such as cataract surgery. Conventional drug delivery methods, such as antibiotic eye drops, have limitations for intraocular drug delivery due to the intrinsic barrier effect of the cornea. Therefore, frequent instillation of antibiotic eyedrops is necessary to reach a sufficient bactericidal concentration inside the eye. In this study, an intraocular implant, MXF-HA, that combines hyaluronic acid (HA) and moxifloxacin (MXF) was developed to increase the efficiency of intraocular drug delivery after surgery. MXF-HA is manufactured as a thin, transparent, yellow-tinted membrane. When inserted into the eye in a dry state, MXF-HA is naturally hydrated and settles in the eye, and the MXF contained therein is delivered by hydrolysis of the polymer over time. It was confirmed through in vivo experiments that MXF delivery was maintained in the anterior chamber of the eye at a concentration sufficient to inhibit Pseudomonas aeruginosa and Staphylococcus aureus for more than 5 days after implantation. These results suggest that MXF-HA can be utilized as a potential drug delivery method for the prevention and treatment of bacterial infections after ophthalmic surgery.

Collagen Structural Changes in Rat Tarsus After Crosslinking

Purpose

Surgery is the standard treatment for floppy eyelid syndrome, but crosslinking (CXL) tarsus has recently been proposed as an alternative. To the best of our knowledge, this study is the first to use second-harmonic generation (SHG) microscopy to examine tarsal collagen ex vivo before and after photo-activated crosslinking. To quantify crosslinking, this study examined fluorescence recovery after photobleaching (FRAP), which indirectly measures tissue stiffness.

Methods

Upper eyelid tarsal plates were dissected from 21 Sprague-Dawley rats (total of 42 tarsal plates). Six normal plates were sent for histopathology and SHG imaging; the remaining 36 were crosslinked with phosphate-buffered saline (PBS) alone or riboflavin in PBS (concentrations of 0.1%, 0.3%, and 0.5%). Tissues were irradiated with 365-nm ultraviolet A light (power, 0.45 mW/cm2) for 30 minutes and immediately underwent SHG microscopy. Stiffness was indirectly measured with FRAP using fluorescein isothiocyanate (FITC)-dextran.

Results

SHG imaging of normal tarsus showed that the organization of collagen bundles is complex and varies greatly depending on location. After crosslinking with high-concentration riboflavin (0.5%), collagen fibers showed clear structural changes, becoming more densely packed and wavier compared to control. FRAP half-time to fluorescence recovery was significantly increased (P < 0.05), indirectly indicating increased tissue stiffness. No structural changes were observed after crosslinking with lower riboflavin concentrations of 0.1% and 0.3%.

Conclusions

This is the first report of SHG microscopy used to image tarsus collagen before and after crosslinking. These results highlight collagen structural changes, with effects on tissue stiffness indirectly confirmed by FRAP.

Translational Relevance

Collagen fibers in the tarsus may be a therapeutic target for crosslinking in order to treat symptomatic floppy eyelid syndrome.

Transepithelial Corneal Crosslinking Using a Novel Ultraviolet Light-Emitting Contact Lens Device: A Pilot Study

Purpose

To evaluate the feasibility of a novel, on-eye UVA light-emitting contact lens device driven by fiber optics for the corneal crosslinking (CXL) of patients with keratoconus.

Methods

In nine corneal transplant candidates with advanced keratoconus a scleral contact lens reservoir containing 0.007% benzalkonium chloride preserved with 0.25% riboflavin-monophosphate was placed on the eye for 30 minutes. The reservoir lens was removed and replaced with the CXLens UVA light-emitting contact lens. A 375-nm UVA light at 4 mW/cm² intensity was delivered for 30 minutes for a dose of 7.2 J/cm². A one-sided paired t-test was used to evaluate mean differences in maximum keratometry, thinnest corneal thickness, and endothelial cell density between screening and 6 months after CXL. A two-sided paired t-test was used to evaluate differences in best-corrected distance visual acuity between screening and 6 months after CXL.

Results

All patients received the treatment as per protocol and adhered to follow-up testing. At 6 months after CXL, treated eyes had an average −1.0 ± 1.6 diopters decrease in the maximum keratometry (P = 0.049), a nonsignificant 2.3 ± 7.5 letter improvement in best-corrected distance visual acuity (P = 0.19), a nonsignificant −17 ± 14 µm decrease in thinnest corneal thickness (P < 0.01), and a nonsignificant −86 ± 266 cells/mm² decrease in endothelial cell density (P = 0.20).

Conclusions

Our pilot study demonstrated the feasibility of the novel CXL device for the treatment of keratoconus and indicates the device is ready for larger scale studies with longer follow-up periods.

Translational Relevance

The novel CXLens on-eye UVA light-emitting contact lens device offers the potential for efficient, high-throughput transepithelial corneal CXL.

Corneal Crosslinking in Refractive Corrections

Corneal crosslinking has been well-described for the treatment of progressive corneal ectasias. Although the goal of treatment in these conditions is the decrease in the risk of progressive steepening of the cornea, studies have shown that flattening of the cornea is achieved in many cases. This finding has led to the postulation that corneal crosslinking may have a potential role in the primary treatment of myopia, and that targeted approaches with more specialized patterns of treatment may be used as primary treatments for astigmatism and hyperopia. In this review, we provide a summary of the clinical and laboratory-based studies evaluating corneal crosslinking as a primary, solitary, refractive treatment for myopia, hyperopia, and astigmatism. Clinical studies thus far are small case series. The primary benefit of refractive corneal crosslinking seems to be the correction of small myopic or hyperopic refractive errors without the need for corneal incisions or tissue removal.

A Novel Therapeutic Approach to Corneal Alkaline Burn Model by Targeting Fidgetin-Like 2, a Microtubule Regulator

Purpose

The purpose of this study was to determine the efficacy of nanoparticle-encapsulated Fidgetin-like 2 (FL2) siRNA (FL2-NPsi), a novel therapeutic agent targeting the FL2 gene, for the treatment of corneal alkaline chemical injury.

Methods

Eighty 12-week-old, male Sprague-Dawley rats were divided evenly into 8 treatment groups: prednisolone, empty nanoparticles, control-NPsi (1 µM, 10 µM, and 20 µM) and FL2-NPsi (1 µM, 10 µM, and 20 µM). An alkaline burn was induced onto the cornea of each rat, which was then treated for 14 days according to group assignment. Clinical, histopathologic, and immunohistochemical analyses were conducted to assess for wound healing. FL2-NPsi-mediated knockdown of FL2 was confirmed by in vitro quantitative polymerase chain reaction (qPCR). Toxicity assays were performed to assess for apoptosis (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling [TUNEL] assay) and nerve damage (whole mount immunochemical staining). Statistical analyses were performed using Student's t-test and ANOVA.

Results

Compared with controls, FL2-NPsi-treated groups demonstrated enhanced corneal wound healing, with the 10 and 20 µM FL2-NPsi-treated groups demonstrating maximum rates of corneal re-epithelialization as assessed by ImageJ software, enhanced corneal transparency, and improved stromal organization on histology. Immunohistochemical analysis of vascular endothelial cells, macrophages, and neutrophils did not show significant differences between treatment groups. FL2-NPsi was not found to be toxic to nerves or induce apoptosis (p = 0.917).

Conclusions

Dose-response studies found both 10 and 20 µM FL2-NPsi to be efficacious in this rat model. FL2-NPsi may offer a novel treatment for corneal alkaline chemical injuries.

Translational Relevance

Basic cell biology findings about the microtubule cytoskeleton were used to design a therapeutic to enhance corneal cell migration, highlighting the promise of targeting microtubules to regulate corneal wound healing.

Penetrating ocular injury from motor vehicle rear-view side-mirror

Purpose

To report a case of penetrating ocular injury due to automobile rear-view side-mirror.

Observations

This is a case of a 49-year-old male who developed penetrating eye injury with a full thickness corneal laceration after isolated motor vehicle damage to the rear-view side-mirror. This patient subsequently required surgical repair of the corneal laceration and likely will need further surgical interventions in the future for ocular rehabilitation.

Conclusions and Importance

Our case of rear-view side mirror caused injury and those previously reported highlight an area of opportunity for injury prevention.

Changes in Collagen Structure and Permeability of Rat and Human Sclera After Crosslinking

Purpose

To use second harmonic generation imaging and fluorescence recovery after photobleaching to demonstrate alterations in scleral collagen structure and permeability after crosslinking in rat and human eyes.

Methods

Excised rat and human scleras were imaged ex vivo with an inverted two-photon excitation fluorescence microscope before and after photochemical crosslinking using riboflavin and 405-nm laser light. Fluorescence recovery after photobleaching was applied to measure the diffusion of fluorescein isothiocyanate–dextran across the sclera.

Results

Crosslinking caused scleral collagen fibers to become wavier and more densely packed, with surface collagen being more affected than deeper collagen fibers. Crosslinked sclera showed significantly decreased permeability in the irradiation zone and also extended as far as 250 µm outside the irradiation zone.

Conclusions

Photochemical crosslinking induced changes in scleral structure and permeability that extended to tissue even outside the irradiation zone.

Translational Relevance

Ultrastructural changes associated with the emerging clinical technique of photochemical scleral crosslinking have not been well characterized. We demonstrate not only changes in scleral collagen by second harmonic generation imaging but also the associated functional changes in tissue permeability by fluorescence recovery after photobleaching. We report the novel finding of reduced permeability extending well beyond the direct irradiation zone. This has implications for control in the clinical setting.

Descemet membrane endothelial keratoplasty for endothelial decompensation after previous radial keratotomy

Purpose

To report Descemet membrane endothelial keratoplasty (DMEK) for endothelial decompensation in an eye with previous radial keratotomy.

Observations

A history of radial keratotomy may hasten endothelial dysfunction. Previously reported surgical treatments include penetrating kerotoplasty and Descemet stripping automated endothelial keratoplasty.

Conclusions and Importance

DMEK may be successfully used in post-RK eyes with good recovery of visual acuity and patient satisfaction.

Effect of Nitric Oxide on Acanthamoeba castellanii

Purpose

Acanthamoeba keratitis is a well-known intractable corneal infectious disease. We investigated the anti-Acanthamoeba effect of exogenous nitric oxide (NO).

Methods

Acanthamoeba castellanii was axenically cultured and exposed to various concentrations of NO donors, such as sodium nitrite, sodium nitroprusside (SNP), and NO-releasing silica nanoparticles (coated in branched polyethylene imine, size:100 nm), for 1 to 7 days (sodium nitrite and SNP: 0, 0.1, 1, 10, 100, and 1000 μM; silica nanoparticles: 0, 6.25, 12.5, 25, 50, and 100 μg/mL). Human corneal epithelial cells (HCECs) were cultured and exposed to sodium nitrite, SNP (0, 0.1, 1, 10, 100, and 1000 μM), and silica nanoparticles for 1, 2, and 3 days.

Results

Sodium nitrite and SNP showed a dose-dependent inhibitory effect on A. castellanii viability. A more prominent inhibitory effect was observed with SNP (less than 10% of organisms survived at 7-day culture with 1000 μM) compared with sodium nitrite. However, more cytotoxicity on HCEC was observed with SNP. NO-releasing silica nanoparticles were successfully internalized into the amoebic cytoplasm and accumulated in large vacuoles. Although blank silica nanoparticles had no inhibitory effect on A. castellanii viability, NO-releasing silica nanoparticles showed a dose-dependent amoebicidal effect. Furthermore, no cystic transformation of A. castellanii was observed under a phase contrast microscope or transmission electron microscope after exogenous NO treatment.

Conclusions

Our results demonstrated the anti-Acanthamoeba effect of exogenous NO. This finding suggests that NO-releasing drug platforms, including nano-carriers, can be a promising therapeutic strategy for Acanthamoeba keratitis.

Toxic anterior segment syndrome-an updated review

Background

Toxic anterior segment syndrome (TASS) can be a rare complication of anterior segment surgery. Here we reviewed the most recent advances in the understanding of TASS.

Methods

English articles related to TASS were retrieved from “PubMed” using the following keywords; “toxic anterior segment syndrome” or “TASS”. The authors of this paper reviewed all the retrieved literature and critical findings were summarized.

Results

The onset of TASS can vary from hours to months. The clinical manifestations are also variable. The causes of TASS are broad and continue to expand and could not be elucidated in over half of the reported cases. Prompt and thorough investigation to explore the causes of TASS is critical. Surgeons should be fully aware and updated regarding possible etiologies and make ceaseless efforts to prevent TASS. This effort begins with establishing TASS prevention protocols and regularly training surgical staff. Proper cleaning of surgical instruments is critical and should follow the guidelines set by The American Society of Cataract and Refractive Surgery TASS Task Force. When TASS occurs, sharing information with other ophthalmologists and reporting new causes is crucial for the prevention of outbreaks.

Conclusions

Anterior segment surgeons should be reminded that TASS is mostly preventable by the establishment of TASS prevention protocols, regular surgical staff training and thorough adherence to recommendations for cleaning and sterilizing intraocular surgical instruments.

Optimal size of pterygium excision for limbal conjunctival autograft using fibrin glue in primary pterygia

BACKGROUND

In our study we describe a method that optimizes size of excision and autografting for primary pterygia along with the use of intraoperative MMC and fibrin glue. Our objective is to propose a simple, optimizedpterygium surgical technique with excellent aesthetic outcomes and low rates of recurrence and otheradverse events.

METHODS

Retrospective chart review of 78 consecutive patients with stage III primary pterygia who underwent an optimal excision technique by three experienced surgeons. The technique consisted of removal of the pterygium head, excision of the pterygium body and Tenon's layer limited in proportion to the length of the head, application of intraoperative mitomycin C to the defect, harvest of superior bulbar limbal conjunctival graft, adherence of graft with fibrin glue. Outcomes included operative time, follow up period, pterygium recurrence, occurrences of incorrectly sized grafts, and other complications.

RESULTS

All patients were followed up for more than a year. Of the 78 patients, there were 2 cases of pterygium recurrence (2.6%). There was one case of wound dehiscence secondary to small-sized donor conjunctivaand one case of over-sized donor conjunctiva, neither of which required surgical correction. There were no toxic complications associated with the use of mitomycin C.

CONCLUSION

Correlating the excision of the pterygium body and underlying Tenon's layer to the length of the pterygium head, along with the use intraoperative mitomycin C, limbal conjunctival autografting, and fibrin adhesionresulted in excellent outcomes with a low rate of recurrence for primary pterygia.

Low recurrence rate of anchored conjunctival rotation flap technique in pterygium surgery

Background

To report the recurrence rate for an anchored conjunctival rotation flap technique in primary pterygium surgery.

Methods

Primary pterygium surgeries performed using anchored conjunctival rotation flap techniques (110 eyes in 110 patients) with a minimum follow-up of 12 months were reviewed. In this technique, a conjunctival flap is rotated to cover the bare sclera and suture-fixated with either 8–0 polyglactin (41 eyes) or 10–0 nylon (69 eyes). The recurrence rate was determined, and the two suture materials utilized were compared.

Results

The recurrence rate was 2.71% (3 cases in 110 eyes) when an anchored conjunctival rotation flap technique was used and patients were monitored for 26.40 ± 17.09 months. Interestingly, the recurrences were only observed in polyglactin-sutured eyes. No recurrence was detected in nylon-sutured eyes. No other complications were observed in either group.

Conclusions

The anchored conjunctival rotation flap technique for pterygium surgery has a relatively low recurrence rate. Nylon suture-fixation of the flap was found to be superior to polyglactin suture-fixation in preventing recurrence.

Electronic supplementary material

The online version of this article (10.1186/s12886-017-0587-z) contains supplementary material, which is available to authorized users.

Comparison of Clinical Trial and Systematic Review Outcomes for the 4 Most Prevalent Eye Diseases

Importance

Suboptimal overlap in outcomes reported in clinical trials and systematic reviews compromises efforts to compare and summarize results across these studies.

Objectives

To examine the most frequent outcomes used in trials and reviews of the 4 most prevalent eye diseases (age-related macular degeneration [AMD], cataract, diabetic retinopathy [DR], and glaucoma) and the overlap between outcomes in the reviews and the trials included in the reviews.

Design, Setting, and Participants

This cross-sectional study examined all Cochrane reviews that addressed AMD, cataract, DR, and glaucoma; were published as of July 20, 2016; and included at least 1 trial and the trials included in the reviews. For each disease, a pair of clinical experts independently classified all outcomes and resolved discrepancies. Outcomes (outcome domains) were then compared separately for each disease.

Main Outcomes and Measures

Proportion of review outcomes also reported in trials and vice versa.

Results

This study included 56 reviews that comprised 414 trials. Although the median number of outcomes per trial and per review was the same (n = 5) for each disease, the trials included a greater number of outcomes overall than did the reviews, ranging from 2.9 times greater (89 vs 30 outcomes for glaucoma) to 4.9 times greater (107 vs 22 outcomes for AMD). Most review outcomes, ranging from 14 of 19 outcomes (73.7%) (for DR) to 27 of 29 outcomes (93.1%) (for cataract), were also reported in the trials. For trial outcomes, however, the proportion also named in reviews was low, ranging from 19 of 107 outcomes (17.8%) (for AMD) to 24 of 89 outcomes (27.0%) (for glaucoma). Only 1 outcome (visual acuity) was consistently reported in greater than half the trials and greater than half the reviews.

Conclusions and Relevance

Although most review outcomes were reported in the trials, most trial outcomes were not reported in the reviews. The current analysis focused on outcome domains, which might underestimate the problem of inconsistent outcomes. Other important elements of an outcome (ie, specific measurement, specific metric, method of aggregation, and time points) might have differed even though the domains overlapped. Inconsistency in trial outcomes may impede research synthesis and indicates the need for disease-specific core outcome sets in ophthalmology.

Non-steroidal anti-inflammatory drugs versus corticosteroids for controlling inflammation after uncomplicated cataract surgery

BACKGROUND

Cataract is a leading cause of blindness worldwide. Cataract surgery is commonly performed but can result in postoperative inflammation of the eye. Inadequately controlled inflammation increases the risk of complications. Non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids are used to prevent and reduce inflammation following cataract surgery, but these two drug classes work by different mechanisms. Corticosteroids are effective, but NSAIDs may provide an additional benefit to reduce inflammation when given in combination with corticosteroids. A comparison of NSAIDs to corticosteroids alone or combination therapy with these two anti-inflammatory agents will help to determine the role of NSAIDs in controlling inflammation after routine cataract surgery.

OBJECTIVES

To evaluate the comparative effectiveness of topical NSAIDs (alone or in combination with topical corticosteroids) versus topical corticosteroids alone in controlling intraocular inflammation after uncomplicated phacoemulsification. To assess postoperative best-corrected visual acuity (BCVA), patient-reported discomfort, symptoms, or complications (such as elevation of IOP), and cost-effectiveness with the use of postoperative NSAIDs or corticosteroids.

SEARCH METHODS

To identify studies relevant to this review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Eyes and Vision Trials Register (2016, Issue 12), MEDLINE Ovid (1946 to December 2016), Embase Ovid (1947 to 16 December 2016), PubMed (1948 to December 2016), LILACS (Latin American and Caribbean Health Sciences Literature Database) (1982 to 16 December 2016), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com; last searched 17 June 2013), ClinicalTrials.gov (www.clinicaltrials.gov; searched December 2016), and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en; searched December 2016).

SELECTION CRITERIA

We included randomized controlled trials (RCTs) in which participants were undergoing phacoemulsification for uncomplicated cataract extraction. We included both trials in which topical NSAIDs were compared with topical corticosteroids and trials in which combination therapy (topical NSAIDs and corticosteroids) was compared with topical corticosteroids alone. The primary outcomes for this review were inflammation and best-corrected visual acuity (BCVA).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the full-text articles, extracted data from included trials, and assessed included trials for risk of bias according to Cochrane standards. The two review authors resolved any disagreements by discussion. We graded the certainty of the evidence using GRADE.

MAIN RESULTS

This review included 48 RCTs conducted in 17 different countries and two ongoing studies. Ten included studies had a trial registry record. Fifteen studies compared an NSAID with a corticosteroid alone, and 19 studies compared a combination of an NSAID plus a corticosteroid with a corticosteroid alone. Fourteen other studies had more than two study arms. Overall, we judged the studies to be at unclear risk of bias. NSAIDs alone versus corticosteroids aloneNone of the included studies reported postoperative intraocular inflammation in terms of cells and flare as a dichotomous variable. Inflammation was reported as a continuous variable in seven studies. There was moderate-certainty evidence of no difference in mean cell value in the participants receiving an NSAID compared with the participants receiving a corticosteroid (mean difference (MD) -0.60, 95% confidence interval (CI) -2.19 to 0.99), and there was low-certainty evidence that the mean flare value was lower in the group receiving NSAIDs (MD -13.74, 95% CI -21.45 to -6.04). Only one study reported on corneal edema at one week postoperatively and there was uncertainty as to whether the risk of edema was higher or lower in the group that received NSAIDs (risk ratio (RR) 0.77, 95% CI 0.26 to 2.29). No included studies reported BCVA as a dichotomous outcome and no study reported time to cessation of treatment. None of the included studies reported the proportion of eyes with cystoid macular edema (CME) at one week postoperatively. Based on four RCTs that reported CME at one month, we found low-certainty evidence that participants treated with an NSAID alone had a lower risk of developing CME compared with those treated with a corticosteroid alone (RR 0.26, 95% CI 0.17 to 0.41). No studies reported on other adverse events or economic outcomes. NSAIDs plus corticosteroids versus corticosteroids aloneNo study described intraocular inflammation in terms of cells and flare as a dichotomous variable and there was not enough continuous data for anterior chamber cell and flare to perform a meta-analysis. One study reported presence of corneal edema at various times. Postoperative treatment with neither a combination treatment with a NSAID plus corticosteroid or with corticosteroid alone was favored (RR 1.07, 95% CI 0.98 to 1.16). We judged this study to have high risk of reporting bias, and the certainty of the evidence was downgraded to moderate. No included study reported the proportion of participants with BCVA better than 20/40 at one week postoperatively or reported time to cessation of treatment. Only one included study reported on the presence of CME at one week after surgery and one study reported on CME at two weeks after surgery. After combining findings from these two studies, we estimated with low-certainty evidence that there was a lower risk of CME in the group that received NSAIDs plus corticosteroids (RR 0.17, 95% CI 0.03 to 0.97). Seven RCTs reported the proportion of participants with CME at one month postoperatively; however there was low-certainty evidence of a lower risk of CME in participants receiving an NSAID plus a corticosteroid compared with those receiving a corticosteroid alone (RR 0.50, 95% CI 0.23 to 1.06). The few adverse events reported were due to phacoemulsification rather than the eye drops.

AUTHORS' CONCLUSIONS

We found insufficient evidence from this review to inform practice for treatment of postoperative inflammation after uncomplicated phacoemulsification. Based on the RCTs included in this review, we could not conclude the equivalence or superiority of NSAIDs with or without corticosteroids versus corticosteroids alone. There may be some risk reduction of CME in the NSAID-alone group and the combination of NSAID plus corticosteroid group. Future RCTs on these interventions should standardize the type of medication used, dosing, and treatment regimen; data should be collected and presented using the Standardization of Uveitis Nomenclature (SUN) outcome measures so that dichotomous outcomes can be analyzed.

The Effects of Nonporous Silica Nanoparticles on Cultured Human Keratocytes

Purpose

Silica nanoparticles (SiNPs) are promising carriers for ophthalmic drug delivery. In this study, we investigated the effect of various sizes of nonporous SiNPs on cultured human keratocytes.

Methods

Three different sizes of SiNPs (50, 100, and 150 nm) were manufactured. Primarily cultured human keratocytes were exposed to different concentrations (0, 25, 50, and 100 μg/mL) of three sizes of SiNPs for up to 72 hours. Intracellular reactive oxygen species (ROS) generation, cellular viability, lactate dehydrogenase (LDH) assay, autophagy, vimentin expression, and mammalian target of rapamycin (mTOR) pathway activation were evaluated. Intracellular distribution of SiNPs was evaluated with transmission electron microscopy.

Results

Transmission electron microscopy revealed SiNPs were taken up by keratocytes inside cytoplasmic vacuoles. Neither nuclear entry of SiNPs nor mitochondrial structural damage was observed. Both intracellular ROS generation and LDH level remained unchanged with up to 100 μg/mL SiNP treatment. Cellular viability was not affected by SiNP treatment. Autophagy showed significant dose-dependent activation with 50- and 100-nm SiNPs. However, mTOR activation remained unchanged. Vimentin expression did not show any significant increase with SiNPs.

Conclusions

Our findings suggested that 50-, 100-, and 150-nm SiNPs did not induce significant cytotoxicity in cultured human keratocytes at concentrations up to 100 μg/mL.

Details of the Collagen and Elastin Architecture in the Human Limbal Conjunctiva, Tenon's Capsule and Sclera Revealed by Two-Photon Excited Fluorescence Microscopy

Purpose

To investigate the architecture and distribution of collagen and elastin in human limbal conjunctiva, Tenon's capsule, and sclera.

Methods

The limbal conjunctiva, Tenon's capsule, and sclera of human donor corneal buttons were imaged with an inverted two-photon excited fluorescence microscope. No fixation process was necessary. The laser (Ti:sapphire) was tuned at 850 nm for two-photon excitation. Backscatter signals of second harmonic generation (SHG) and autofluorescence (AF) were collected through a 425/30-nm and a 525/45-nm emission filter, respectively. Multiple, consecutive, and overlapping (z-stack) images were acquired. Collagen signals were collected with SHG, whereas elastin signals were collected with AF.

Results

The size and density of collagen bundles varied widely depending on depth: increasing from conjunctiva to sclera. In superficial image planes, collagen bundles were <10 μm in width, in a loose, disorganized arrangement. In deeper image planes (episclera and superficial sclera), collagen bundles were thicker (near 100 μm in width) and densely packed. Comparatively, elastin fibers were thinner and sparse. The orientation of elastin fibers was independent of collagen fibers in superficial layers; but in deep sclera, elastin fibers wove through collagen interbundle gaps. At the limbus, both collagen and elastin fibers were relatively compact and were distributed perpendicular to the limbal annulus.

Conclusions

Two-photon excited fluorescence microscopy has enabled us to understand in greater detail the collagen and elastin architecture of the human limbal conjunctiva, Tenon's capsule, and sclera.

The effect of ocular biometric factors on the accuracy of various IOL power calculation formulas

Background

To evaluate how differences in ocular biometry affects the Hoffer Q, Holladay 1, SRK/T, and Haigis intraocular lens power calculation formulae predictions.

Methods

This study was performed on 91 eyes of 91 patients who underwent uneventful cataract surgery. Ocular biometry values were measured using the IOL Master 500, and intraocular lens (IOL) power was calculated using the Haigis, Hoffer Q, Holladay 1, and SRK/T formulas. We calculated the expected difference (ED) of each 3rd generation formula from the Haigis formula by subtracting the predicted refraction of the Haigis formula from the predicted refraction of each 3rd generation formula. Post-operative anterior chamber depth (ACD) was measured at 1 month after surgery using the IOL master. We calculated errors of each formula by subtracting predicted from manifest refraction at post-operative 1 month. Correlation analysis was performed between ocular biometry values, formula expectation values, formula errors and absolute formula errors.

Results

Multiple regression analysis revealed that preoperative ACD was the only significant factor for ED prediction in all of the 3rd generation formulas. For mean errors, axial length and post-operative 1-month change of ACD (delta ACD) correlated significantly with the errors in all 3rd generation formulas, but not with errors of the Haigis formula. Median absolute error (MedAE) of the formulas were 0.40 D for the Hoffer Q formula, 0.37 D for the Holladay formula, 0.34 D for the SRK/T formula, and 0.41 D for the Haigis formula. The MAE of the formulas were 0.50 ± 0.47 D for the Hoffer Q formula, 0.50 ± 0.50 D for the Holladay formula, 0.47 ± 0.51 D for the SRK/T formula, and 0.50 ± 0.47 D for the Haigis formula.

Conclusion

Regarding ED between the third generation and Haigis formulas, preoperative ACD demonstrated the greatest influence. Calculating mean absolute errors of the formulas, all IOL formulas showed excellent and comparable accuracy. Post-operative change (delta) of ACD correlated significantly with errors of third generation formulas according to simulated ACD.

Laser-assisted subepithelial keratectomy (LASEK) versus laser-assisted in-situ keratomileusis (LASIK) for correcting myopia

BACKGROUND

Near-sightedness, or myopia, is a condition in which light rays entering the eye along the visual axis focus in front of the retina, resulting in blurred vision. Myopia can be treated with spectacles, contact lenses, or refractive surgery. Options for refractive surgery include laser-assisted subepithelial keratectomy (LASEK) and laser-assisted in-situ keratomileusis (LASIK). Both procedures utilize a laser to shape the corneal tissue (front of the eye) to correct refractive error, and both create flaps before laser treatment of corneal stromal tissue. Whereas the flap in LASEK is more superficial and epithelial, in LASIK it is thicker and also includes some anterior stromal tissue. LASEK is considered a surface ablation procedure, much like its predecessor, photorefractive keratectomy (PRK). LASEK was developed as an alternative to PRK to address the issue of pain associated with epithelial debridement used for PRK. Assessing the relative benefits and risks/side effects of LASEK and LASIK warrants a systematic review.

OBJECTIVES

To assess the effects of LASEK versus LASIK for correcting myopia.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Eyes and Vision Trials Register (2016, Issue 10); MEDLINE Ovid (1946 to 24 October 2016); Embase.com (1947 to 24 October 2016); PubMed (1948 to 24 October 2016); LILACS (Latin American and Caribbean Health Sciences Literature Database; 1982 to 24 October 2016); the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), last searched 20 June 2014; ClinicalTrials.gov (www.clinicaltrials.gov); searched 24 October 2016; and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en); searched 24 October 2016. We did not use any date or language restrictions in the electronic searches for trials.

SELECTION CRITERIA

We considered only randomized controlled trials (RCTs) for the purposes of this review. Eligible RCTs were those in which myopic participants were assigned randomly to receive either LASEK or LASIK in one or both eyes. We also included paired-eye studies in which investigators randomly selected which of the participant's eyes would receive LASEK or LASIK and assigned the other eye to the other procedure. Participants were men or women between the ages of 18 and 60 years with myopia up to 12 diopters (D) and/or myopic astigmatism of severity up to 3 D, who did not have a history of prior refractive surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened all reports and assessed the risk of bias in trials included in this review. We extracted data and summarized findings using risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes. In the absence of clinical and methodological heterogeneity across trials, we used a random-effects model to calculate summary effect estimates. We used a fixed-effect model when including fewer than three trials in a meta-analysis. When clinical, methodological, or statistical heterogeneity was observed across trials, we reported our findings in a narrative synthesis.

MAIN RESULTS

We identified four eligible trials with 538 eyes of 392 participants for the review, but only three trials (154 participants) provided outcome data for analysis. We found no ongoing trials. Two of four trials were from China, one trial was from Turkey, and the location of one trial was not reported. The risk of bias for most domains was unclear due to poor reporting of trial methods; no trial had a protocol or trial registry record. Three trials enrolled participants with mild to moderate myopia (less than -6.50 D); one trial included only participants with severe myopia (more than -6.00 D).The evidence showed uncertainty in whether there is a difference between LASEK and LASIK in uncorrected visual acuity (UCVA) at 12 months, the primary outcome in our review. The RR and 95% confidence interval (CI) at 12 months after surgery was 0.96 (95% CI 0.82 to 1.13) for UCVA of 20/20 or better and 0.90 (95% CI 0.67 to 1.21) for UCVA of 20/40 or better based on data from one trial with 57 eyes (very low-certainty evidence). People receiving LASEK were less likely to achieve a refractive error within 0.5 diopters of the target at 12 months follow-up (RR 0.69, 95% CI 0.48 to 0.99; 57 eyes; very low-certainty evidence). One trial reported mild corneal haze at six months in one eye in the LASEK group and none in the LASIK group (RR 2.11, 95% CI 0.57 to 7.82; 76 eyes; very low-certainty evidence). None of the included trials reported postoperative pain score or loss of visual acuity, spherical equivalent of the refractive error, or quality of life at 12 months.Refractive regression, an adverse event, was reported only in the LASEK group (8 of 37 eyes) compared with none of 39 eyes in the LASIK group in one trial (low-certainty evidence). Other adverse events, such as corneal flap striae and refractive over-correction, were reported only in the LASIK group (5 of 39 eyes) compared with none of 37 eyes in the LASEK group in one trial (low-certainty evidence).

AUTHORS' CONCLUSIONS

Overall, from the available RCTs, there is uncertainty in how LASEK compares with LASIK in achieving better refractive and visual results in mildly to moderately myopic participants. Large, well-designed RCTs would be required to estimate the magnitude of any difference in efficacy or adverse effects between LASEK and LASIK for treating myopia or myopic astigmatism.

The Effect of Silica Nanoparticles on Human Corneal Epithelial Cells

Ocular drug delivery is an interesting field in current research. Silica nanoparticles (SiNPs) are promising drug carriers for ophthalmic drug delivery. However, little is known about the toxicity of SiNPs on ocular surface cells such as human corneal epithelial cells (HCECs). In this study, we evaluated the cytotoxicity induced by 50, 100 and 150 nm sizes of SiNPs on cultured HCECs for up to 48 hours. SiNPs were up-taken by HCECs inside cytoplasmic vacuoles. Cellular reactive oxygen species generation was mildly elevated, dose dependently, with SiNPs, but no significant decrease of cellular viability was observed up to concentrations of 100 μg/ml for three different sized SiNPs. Western blot assays revealed that both cellular autophagy and mammalian target of rapamycin (mTOR) pathways were activated with the addition of SiNPs. Our findings suggested that 50, 100 and 150 nm sized SiNPs did not induce significant cytotoxicity in cultured HCECs.

Indocyanine Green Dye Enhanced Vascular Welding With the Near Infrared Diode Laser

For vascular anastomosis, use of topical photosensitizing dye enhances selec tive delivery of laser energy to target tissue, thus reducing the amount of collat eral thermal injury and threshold power required for welding. The authors compared the threshold power density needed to weld abdominal aortotomies in rabbits with and without photosensitizing dye. With continuous wave diode la ser energy, the threshold for welding using the dye indocyanine green (ICG) was 150 mW (power density 4.8 watts/cm2 at spot diameter of 2 mm). Without dye enhancement, tissue effects were not observed even at the highest energy output available from the laser (300 mW, power density 9.6 watts/cm2). Immediately after welding, the mean bursting pressure for the welds was 260 mm Hg. In survival studies, no anastomotic ruptures, thomboses, or aneurysms were iden tified. Use of photosensitizing dyes for tissue welding is feasible and may allow arterial welding with lower power laser systems and cause less thermal trauma by lowering threshold power levels.

Second Harmonic Generation Imaging Analysis of Collagen Arrangement in Human Cornea

PURPOSE

To describe the horizontal arrangement of human corneal collagen bundles by using second harmonic generation (SHG) imaging.

METHODS

Human corneas were imaged with an inverted two photon excitation fluorescence microscope. The excitation laser (Ti:Sapphire) was tuned to 850 nm. Backscatter signals of SHG were collected through a 425/30-nm bandpass emission filter. Multiple, consecutive, and overlapping image stacks (z-stacks) were acquired to generate three dimensional data sets. ImageJ software was used to analyze the arrangement pattern (irregularity) of collagen bundles at each image plane.

RESULTS

Collagen bundles in the corneal lamellae demonstrated a complex layout merging and splitting within a single lamellar plane. The patterns were significantly different in the superficial and limbal cornea when compared with deep and central regions. Collagen bundles were smaller in the superficial layer and larger in deep lamellae.

CONCLUSIONS

By using SHG imaging, the horizontal arrangement of corneal collagen bundles was elucidated at different depths and focal regions of the human cornea.

New Details of the Human Corneal Limbus Revealed With Second Harmonic Generation Imaging

PURPOSE

To report novel findings of the human corneal limbus by using second harmonic generation (SHG) imaging.

METHODS

Corneal limbus was imaged by using an inverted two-photon excitation fluorescence microscope. Laser (Ti:Sapphire) was tuned at 850 nm for two-photon excitation. Backscatter signals of SHG and autofluorescence (AF) were collected through a 425/30-nm emission filter and a 525/45-emission filter, respectively. Multiple, consecutive, and overlapping image stacks (z-stack) were acquired for the corneal limbal area.

RESULTS

Two novel collagen structures were revealed by SHG imaging at the limbus: an anterior limbal cribriform layer and presumed anchoring fibers. Anterior limbal cribriform layer is an intertwined reticular collagen architecture just beneath the limbal epithelial niche and is located between the peripheral cornea and Tenon's/scleral tissue. Autofluorescence imaging revealed high vascularity in this structure. Central to the anterior limbal cribriform layer, radial strands of collagen were found to connect the peripheral cornea to the limbus. These presumed anchoring fibers have both collagen and elastin and were found more extensively in the superficial layers than deep layer and were absent in very deep limbus near Schlemm's canal.

CONCLUSIONS

By using SHG imaging, new details of the collagen architecture of human corneal limbal area were elucidated. High resolution images with volumetric analysis revealed two novel collagen structures.

Risk Factors for Pterygium in Korea: The Korean National Health and Nutrition Examination Survey V, 2010-2012

The aim of this study is to report general and age-specific risk factors for pterygium prevalence in the Korean population.This in an observational case series study.Data from total 24,812 participants (age 40 years or older) from the Korean National Health and Nutrition Examination Surveys conducted from 2010 to 2012 were retrieved. After applying exclusion criteria, data from 13,204 participants (821 with pterygium and 12,383 without) were used for univariate and multivariate analyses. General risk factors were identified and participants were grouped by decade: 40 s, 50 s, 60 s, 70 s, and 80+. Age-specific risk factors were investigated for each group.After univariate analysis, 2 multiple regression models were constructed. Model 1: age + sex + spherical equivalent (SE) + sun exposure hours + occupation (indoor vs outdoor) + residency area (rural vs urban) + education level; model 2: age + sex + SE + sun exposure hours. In model 1, older age (odds ratio [OR]: 1.05 95% confidence interval [CI]: 1.05-1.06), male gender (OR: 1.28, 95% CI: 1.01-1.61), and longer sun exposure hours (OR: 1.47, 95% CI: 1.11-1.94) were significant risk factors for pterygium prevalence whereas higher level of education (elementary school vs college, OR: 3.98, 95% CI: 2.24-7.06) and urban residency (vs rural residency, OR: 0.56, 95% CI: 0.45-0.70) were protective factors. Higher SE (OR 1.11, 95% CI: 1.03-1.19) refractive error was considered a risk factor when using model 2 for the analysis. Age-specific risk factors were different in each age group. Male gender was associated with higher pterygium prevalence in younger age groups while longer sun exposure (5+ hours/day) increased pterygium prevalence in older age groups.Previously characterized risk factors were also found in this large population study. However, we found that risk factors may vary according to the age group. Myopic eyes were found to have lower prevalence than hyperopic eyes.

The effect of corneal irregularity on astigmatism measurement by automated versus ray tracing keratometry

The aim of this study was to compare the effect of corneal irregularity on astigmatism assessment using automated keratometry (AK) (IOLMaster) versus ray tracing keratometry (Pentacam). This is an observational case series approved by the institutional review board of Dongguk University Hospital, Goyang, South Korea. A total of 207 eyes of 207 cataract patients were included. Preoperative corneal astigmatism was measured by both IOLMaster and Pentacam. Corneal irregularity index (IR) was calculated in Fourier analysis map of Pentacam. AK by IOLMaster and total corneal refractive power (TCRP, 3 mm and 4 mm zone analysis with pupil centered) by Pentacam were selected and the difference between the 2 measurements (delta Δ) was calculated using vector analysis. Ocular residual astigmatism (ORA) after cataract surgery was calculated by subtracting 6-month postoperative refractive astigmatism (RA) measurements from corresponding preoperative values (AK, TCRP3, and TCRP4). The mean irregularity index measured was 0.042 ± 0.019 mm (mean ± standard deviation) and was positively correlated with age and magnitude of corneal astigmatism (P < 0.001 and P < 0.05). The difference (Δ) between TCRPs and AK (ΔTCRPs-AK) was 0.43 ± 0.37 (TCRP3) and 0.39 ± 0.35 (TCRP4) diopters. Linear regression analysis revealed that age (P < 0.001), IR (P < 0.001), and AK (P < 0.001) were positively correlated with ΔTCRPs-AK. In highly irregular corneas (IR over 0.77 diopters: mean + 2 standard deviation), postoperative ORAs calculated using TCRPs were significantly lower than ORAs calculated using AK. Corneal irregularities significantly impact astigmatism assessment by IOLMaster (AK) and Pentacam (TCRPs). Compared with AK, TCRPs were more accurate in predicting postoperative residual astigmatism in highly irregular corneas.

Regeneration of corneal epithelium utilizing a collagen vitrigel membrane in rabbit models for corneal stromal wound and limbal stem cell deficiency

PURPOSE

This study was performed to evaluate the potential of a collagen-based membrane, collagen vitrigel (CV), for reconstructing corneal epithelium in the stromal wound and limbal stem cell deficiency (LSCD) models.

METHODS

Three groups of rabbits were used in the stromal wound model: CV affixed using fibrin glue (CV + FG group, n = 9), fibrin glue only (FG group, n = 3) and an untreated control group (n = 3). In the LSCD model, one group received CV containing human limbal epithelial cells (CV + hLEC group, n = 2) and the other was an untreated control (n = 1). Gross observation, including fluorescent staining, pathological examination, immunohistochemistry and electron microscopy, was used to evaluate the effect of CV on the corneal epithelium.

RESULTS

In the stromal wound model, fluorescent staining showed that epithelial reconstruction occurred as rapidly in the CV + FG group as it did in the control group. The pathological examination proved that the CV supported a healthy corneal epithelium in the CV + FG group, whereas FG led to hypertrophy and inappropriate differentiation of corneal epithelium in the FG group. In the LSCD model, the corneas in the CV + hLEC group showed sustained tissue transparency with good epithelialization, low inflammatory response and reduced neovascularization. However, the control cornea was translucent and showed high amounts of inflammation and neovascularization.

CONCLUSION

We have demonstrated that CV supports corneal epithelial differentiation and prevents epithelial hypertrophy, in addition to serving as a scaffold for hLEC transplantation, without complications.

Transient corneal edema is a predictive factor for pseudophakic cystoid macular edema after uncomplicated cataract surgery

PURPOSE

To report transient corneal edema after phacoemulsification as a predictive factor for the development of pseudophakic cystoid macular edema (PCME).

METHODS

A total of 150 eyes from 150 patients (59 men and 91 women; mean age, 68.0 ± 10.15 years) were analyzed using spectral domain optical coherence tomography 1 week and 5 weeks after routine phacoemulsification cataract surgery. Transient corneal edema detected 1 week after surgery was analyzed to reveal any significant relationship with the development of PCME 5 weeks after surgery.

RESULTS

Transient corneal edema developed in 17 (11.3%) of 150 eyes 1 week after surgery. A history of diabetes mellitus was significantly associated with development of transient corneal edema (odds ratio [OR], 4.04; 95% confidence interval [CI], 1.41 to 11.54; p = 0.011). Both diabetes mellitus and transient corneal edema were significantly associated with PCME development 5 weeks after surgery (OR, 4.58; 95% CI, 1.56 to 13.43; p = 0.007; and OR, 6.71; CI, 2.05 to 21.95; p = 0.003, respectively). In the 8 eyes with both diabetes mellitus and transient corneal edema, 4 (50%) developed PCME 5 weeks after surgery.

CONCLUSIONS

Transient corneal edema detected 1 week after routine cataract surgery is a predictive factor for development of PCME. Close postoperative observation and intervention is recommended in patients with transient corneal edema.

Effect of 0.025% FK-506 eyedrops on botulinum toxin B-induced mouse dry eye

PURPOSES

To investigate the effect of FK-506 eye drops on Botulinum toxin B (BTX-B)-induced mouse dry eye.

METHODS

Forty-five CBA/J mice were followed up for 4 weeks after treatment with 0.025% FK-506, vehicle or 0.9% saline eye drops 3 days after intralacrimal glands injection with 20 milliunits BTX-B. Tear production, corneal fluorescein staining, the mRNA, and protein expression of cytokines were measured. The activation of nuclear factor-κB (NF-κB) was detected by Western blotting. The infiltration of inflammatory cells was examined by immunohistochemistry.

RESULTS

After treated with FK-506 eye drops, aqueous tear production in the mice began to recover at week 1, and then increased to the levels of pre-BTX-B injection at week 4 (2.21 ± 0.43 vs. 2.52 ± 0.71 mm, t = 0.84, P > 0.05). The severity of corneal epithelial defects was alleviated at week 2 and further improved at week 4 when compared with those in the vehicle- and saline-treated groups. The gene expression of IL-1β and TNF-α in the FK-506 and vehicle-treated groups were 47.01% and 45.56%, 85.91% and 115.83% of that in the saline-treated group in the ocular surface, while in the lacrimal glands 49.16% and 67.60%, 94.91% and 95.77% of that in the saline-treated group, respectively. The ratio of phosphorylated IκB-α to total IκB-α in the keratoconjunctival tissues was lower in the FK-506-treated group than in the vehicle- and saline-treated groups (both P < 0.05). No inflammatory cells were detected in all groups.

CONCLUSIONS

Topical application of FK-506 can inhibit NF-κB activation and related inflammatory response and alleviate the signs of dry eye.

Vitreous hyper-reflective dots in optical coherence tomography and cystoid macular edema after uneventful phacoemulsification surgery

Purpose

To report the observation of hyper-reflective dots in the vitreous cavity using spectral domain optical coherence tomography (SD-OCT) after uneventful phacoemulsification cataract surgery and to investigate their association with cystoid macular edema (CME).

Materials and Methods

Medical records of consecutive Asian patients who had no preoperative retinopathy and underwent uneventful phacoemulsification cataract surgery from March 2012 through February 2013 were reviewed. SD-OCTs were performed before, 1 week, and 1 month after surgery. The number of vitreous hyper-reflective dots (VHDs) was counted in 5 OCT images of high-definition 5-line raster scans. The development of CME was assessed using postoperative 1-month OCT.

Results

In 74 eyes of 74 patients, all of three SD-OCTs with a signal to noise ratio of 0.6 or more were available and were analyzed in this study. In preoperative OCT, the VHD was observed in 2 (2.7%) of 74 eyes; one eye had 1 VHD and the other eye had 2 VHDs. In 72 eyes with no preoperative VHD, VHDs were observed in 40 (55.6%) eyes at 1 week after the surgery. In the multivariate analysis, the number of VHDs measured at 1 week after the surgery was significantly associated with CME development at 1 month after the surgery (odds ratio = 1.93, 95% confidence interval = 1.15 to 3.24, P = 0.012).

Conclusions

VHDs were frequently observed in OCT after uneventful phacoemulsification cataract surgery. VHDs observed at 1 week after the surgery may be a risk factor for the development of pseudophakic CME. Further studies are needed to identify the source of the VHDs.

Total anterior corneal surface and epithelial stem cell harvesting: current microkeratomes and beyond

Currently, most corneal lamellar allografts are performed by manually dissecting donor corneoscleral material for transplantation. Manual dissection is technically challenging and time intensive, and excessive handling of tissue may decrease the likelihood of obtaining viable grafts. These mechanical factors, along with problems controlling immune rejection, have prevented limbal stem cell lamellar allografts in particular from becoming more widely used. Anterior lamellar keratoplasty is gaining in clinical importance and usage but is still only practiced by a limited number of surgeons. Recently, new mechanical and femtosecond laser microkeratomes have been adapted to harvest the anterior corneal surface, including the limbal stem cell region. Preliminary results have been encouraging and give hope that this technique may prove to be of benefit to patients in the future.

Predicting ocular residual astigmatism using corneal and refractive parameters: a myopic eye study

PURPOSE

To investigate the nature of ocular residual astigmatism (ORA) in myopic patients and to identify indicators to predict a patient's ORA from corneal and ocular refractive data.

METHODS

In total, 356 myopic eyes from 178 patients (M:F = 41:137) were examined using a Scheimpflug keratometer (Pentacam) and a wavefront analyzer (WaveScan). Vertex distance-adjusted total ocular astigmatism and corneal astigmatism [anterior corneal power (ACP) and true net power (TNP)] were used to calculate ORA, respectively. A power vector system (J0 and J45) was adopted for the astigmatism analysis.

RESULTS

The mean age of the study eyes was 27.6 ± 5.0 years, and mean refractive spherical equivalent, sphere and cylinder was -4.94 ± 1.90 diopter, -4.42 ± 1.87 diopter, and -1.05 ± 0.82, respectively. Corneal astigmatism measured by TNP was more representative of total ocular astigmatism than ACP (p < 0.001). Both the J0 and J45 components of ORA showed significant negative correlation with corneal astigmatism measured by ACP and TNP (p < 0.001). ORA (J0 and J45) was negatively correlated with total ocular spherical equivalent and positively correlated with total ocular astigmatism.

CONCLUSIONS

We verified the general compensatory effect of corneal astigmatism by internal optics in myopic patients. TNP was closer to refractive astigmatism than ACP was. Total ocular spherical equivalent and total ocular astigmatism showed significant correlation with ORA. Therefore these can be possible indicators to predict ORA.

Viral transgene expression delivered by repeat intraocular adenoviral vector injection: in vivo live imaging study

We delivered adenovirus vector (Ad) via intravitreous injection and monitored transgene (luciferase) expression in living mice (BALB/c) at multiple time points. In vivo live imaging technology was able to assess dynamically intraocular luciferase expression in a single animal population throughout the entire experiment period. Using this information, we were able to determine the optimal time point for readministration of Ad into the eyes and to dynamically study the time course of expression of a second Ad administration. Optical imaging demonstrated the limited period of transgene expression in eyes. Significant transgene signal was also detected in livers. The repeat intraocular delivery of the adenovirus resulted in significant blunting of transgene expression in both eyes and livers compared to the initial delivery. Periocular corticosteroid (triamcinolone acetonide) injection combined with initial Ad delivery was effective to rescue luciferase expression on repeat Ad vector delivery. However, this effect was not observed when corticosteroid was combined with repeat Ad delivery. Although corticosteroid enhanced ocular transgene expression, it also increased transgene expression in liver, which has potential safety implications. This dynamic transgene expression in eyes was successfully traced and monitored via a live imaging technique.