Pseudophakic bullous keratopathy

Narrative review after post-hoc trial analysis of factors that predict corneal endothelial cell loss after phacoemulsification: Tips for improving cataract surgery research

PURPOSE

Identifying pre/perioperative factors that predict corneal endothelial-cell loss (ECL) after phacoemulsification may reveal ways to reduce ECL. Our literature analysis showed that 37 studies have investigated one or several such factors but all have significant limitations. Therefore, the data of a large randomized controlled trial (PERCEPOLIS) were subjected to post-hoc multivariate analysis determining the ability of nine pre/perioperative variables to predict ECL.

METHODS

PERCEPOLIS was conducted in 2015-2016 to compare two phacoemulsification techniques (subluxation and divide-and-conquer) in terms of 3-month ECL. Non-inferiority between the techniques was found. In the present study, post-hoc univariate and multivariate analyses were conducted to determine associations between ECL and age, sex, cataract density, preoperative endothelial-cell density, phacoemulsification technique, effective phaco time (EPT), and 2-hour central-corneal thickness. The data are presented in the context of a narrative review of the literature.

RESULTS

Three-month data were available for 275 patients (94% of the randomized cohort; mean age, 74 years; 58% women). Mean LOCSIII cataract grade was 3.2. Mean EPT was 6 seconds. Mean ECL was 13%. Only an older age (beta = 0.2%, p = 0.049) and higher EPT (beta = 1.2%, p = 0.0002) predicted 3-month ECL. Cataract density was significant on univariate (p = 0.04) but not multivariate analysis. The other variables did not associate with ECL.

CONCLUSIONS

Older age may amplify ECL due to increased endothelial cell fragility. EPT may promote ECL via cataract density-dependent and -independent mechanisms that should be considered in future phacoemulsification research aiming to reduce ECL. Our literature analysis showed that the average ECL for relatively unselected consecutively-sampled cohorts is 12%.

Evaluation of biophysical alterations in the epithelial and endothelial layer of patients with Bullous Keratopathy

The cornea is a fundamental ocular tissue for the sense of sight. Thanks to it, the refraction of two-thirds of light manages to participate in the visual process and protect against mechanical damage. Because it is transparent, avascular, and innervated, the cornea comprises five main layers: Epithelium, Bowman's layer, stroma, Descemet's membrane, and endothelium. Each layer plays a key role in the functionality and maintenance of ocular tissue, providing unique ultrastructural and biomechanical properties. Bullous Keratopathy (BK) is an endothelial dysfunction that leads to corneal edema, loss of visual acuity, epithelial blisters, and severe pain, among other symptoms. The corneal layers are subject to changes in their biophysical properties promoted by Keratopathy. In this context, the Atomic Force Microscopy (AFM) technique in air was used to investigate the anterior epithelial surface and the posterior endothelial surface, healthy and with BK, using a triangular silicone tip with a nominal spring constant of 0.4 N/m. Six human corneas (n = 6) samples were used for each analyzed group. Roughness data, calculated by third-order polynomial adjustment, adhesion, and Young's modulus, were obtained to serve as a comparison and identification of morphological and biomechanical changes possibly associated with the pathology, such as craters and in the epithelial layer and exposure of a fibrotic layer due to loss of the endothelial cell wall. Endothelial cell membrane area and volume data were calculated, obtaining a relevant comparison between the control and patient. Such results may provide new data on the physical properties of the ocular tissue to understand the physiology of the cornea when it has pathology.

Five-year clinical outcomes of 107 consecutive DMEK surgeries

PURPOSE

The long-term clinical outcomes, postoperative complications, and graft survival of Descemet-membrane endothelial keratoplasty (DMEK) remain poorly understood. We retrospectively assessed these variables in all consecutive eyes that underwent DMEK for any indication in 2014-2018. The findings were compared to the long-term DMEK studies of five other groups (3-10-year follow-up).

METHODS

Patients underwent ophthalmological tests preoperatively, at 1, 3, 6, and 12 postoperative months, and then annually. Five-year graft survival was determined by Kaplan-Meier estimator. Change in best-corrected visual acuity (BCVA), endothelial-cell density (ECD), and central-corneal thickness (CCT) at each timepoint was determined.

RESULTS

107 eyes (80 patients; 72 years old; 67% female) underwent first-time DMEK for uncomplicated Fuchs endothelial corneal dystrophy (94% of eyes), pseudophakic bullous keratopathy (3%), and regraft after previous keratoplasty (3%). The most common complication was graft detachment requiring rebubbling (18%). Thirteen grafts (12%) failed at ≤15 months. Cumulative 5-year graft-survival probability was 88% (95% confidence intervals = 79-94%). BCVA improved from 0.6 logMAR preoperatively to 0.05 logMAR at 1 year (p<0.0001) and then remained stable. Donor ECD dropped by 47% at 6 postoperative months and then continued to decrease by 4.0%/year. Five-year endothelial-cell loss was 65% (from 2550 to 900 cells/mm2). CCT dropped from 618 to 551 μm at 5 years (p<0.0001). These findings are generally consistent with previous long-term DMEK studies.

CONCLUSIONS

DMEK has low complication and high graft-survival rates and excellent clinical outcomes that persist up to 5 years post-surgery. DMEK seems to be a safe and effective treatment in the long term.

Corneal Edema after Cataract Surgery

This systematic review investigates the prevalence and underlying causes of corneal edema following cataract surgery employing manual phacoemulsification. A comprehensive search encompassing databases such as PubMed, Embase, ProQuest, Cochrane Library, and Scopus was conducted, focusing on variables encompassing cataract surgery and corneal edema. Two independent reviewers systematically extracted pertinent data from 103 articles, consisting of 62 theoretical studies and 41 clinical trials. These studies delved into various aspects related to corneal edema after cataract surgery, including endothelial cell loss, pachymetry measurements, visual performance, surgical techniques, supplies, medications, and assessments of endothelial and epithelial barriers. This review, encompassing an extensive analysis of 3060 records, revealed significant correlations between corneal edema and endothelial cell loss during phacoemulsification surgery. Factors such as patient age, cataract grade, and mechanical stress were identified as contributors to endothelial cell loss. Furthermore, pachymetry and optical coherence tomography emerged as valuable diagnostic tools for assessing corneal edema. In conclusion, this systematic review underscores the link between corneal edema and endothelial cell loss in manual phacoemulsification cataract surgery. It highlights the relevance of factors like patient demographics and diagnostic modalities. However, further research is essential to unravel the complexities of refractive changes and the underlying mechanisms.

Corneal Outcomes Following Cataract Surgery Using Ophthalmic Viscosurgical Devices Composed of Chondroitin Sulfate-Hyaluronic Acid: A Systematic Review and Meta-Analysis

Background

Ophthalmic viscosurgical devices (OVDs) are commonly used during cataract surgery to protect the corneal endothelium. A systematic literature review and meta-analysis were conducted to assess the clinical evidence of OVDs composed of chondroitin sulfate-hyaluronic acid (CS-HA) versus other OVDs in maintaining endothelial cell density (ECD) and corneal thickness (CT).

Methods

MEDLINE and EMBASE databases were searched from 2000 to 2020. Randomized controlled trials (RCTs, N ≥ 20 per group) comparing an OVD containing CS-HA (ie, VISCOAT^®, DuoVisc^® or DisCoVisc^®) to any other OVD were included. The identified comparators were limited to the OVDs found in the literature, which included those composed of HA-only or hydroxypropyl methylcellulose (HPMC). Outcomes of focus included changes in ECD (baseline to 3 months) and CT (baseline to 24 hours). Meta-analyses were performed using R software, to assess mean differences (MD) in ECD and CT change between CS-HA OVDs and HA-only or HPMC OVDs.

Results

A total of 966 abstracts were screened, and data were extracted from 12 RCTs. Meta-analyses using a random-effects model revealed significantly lower percent (%) decrease in ECD for CS-HA OVDs compared to both HA-only (MD: -4.10%; 95% CI: -5.81 to -2.40; p < 0.0001; 9 studies) and HPMC (MD: -6.47%; 95% CI: -10.41 to -2.52; p = 0.001; 2 studies) products. Similarly, % CT increase was significantly lower with CS-HA than with HA-only OVDs (MD: -3.22%; 95% CI: -6.24% to -0.20%; p = 0.04; 4 studies). However, there were no significant differences when comparing % CT change between CS-HA and HPMC OVDs (MD: 2.65%; 95% CI: -0.43% to 0.95%; p = 0.4; 2 studies).

Conclusion

CS-HA OVDs lead to less postoperative loss of endothelial cells and may better protect corneal endothelium during cataract surgery, relative to other OVDs. Future randomized studies may be needed to solidify these findings.

Role of corneal collagen cross-linking in bullous keratopathy: A systematic review

Corneal cross-linking (CXL), a corneal strengthening procedure, is known to alter anterior stroma swelling behavior and is one of the treatment modalities of bullous keratopathy (BK). There are multiple studies published on the role of CXL in the treatment of BK. These articles had heterogeneous study population, different protocols used, and variable conclusions. This systematic review aimed to determine the role of CXL in the treatment of BK. The primary outcomes considered were changes in central corneal thickness (CCT) after 1, 3, and 6 months of CXL. The secondary outcome measures were changes in visual acuity, corneal clarity, subjective symptoms, and complications after CXL. We included randomized control trials (RCTs), observational and interventional studies, and case series with reports of more than 10 cases in this review. In RCTs, the mean pre-CXL CCT (794.0 ± 178.5 μm) in the intervention group (n = 37), decreased at 1 month (750.9 ± 154.3 μm) followed by a subsequent increase, but this difference was not significant during the 6-month follow-up (P- value 0.28, 0.82, and 0.82 at 1, 3, and 6 months, respectively). In noncomparative clinical studies (n = 188), the mean pre-CXL CCT (794.0 ± 178.5 μm) decreased at 1 month (710.9 ± 127.2 μm, P < 0.0001). Seven of the 11 articles included in the review reported no significant improvement in vision with CXL. The initial improvement in corneal clarity and clinical symptoms was not sustained. Current evidence suggests that CXL has short-term efficacy in the treatment of BK. More RCTs with high-quality evidence are needed.

Histopathology of the Host Cornea Following Penetrating Keratoplasty

INTRODUCTION

To study the ultra-structural changes in the diseased corneal cells by histopathology, electron microscopy, and immunohistochemistry using conventional antisera and monoclonal antibodies with the ultimate goal of justifying pre-treatment and post-treatment advice and, if necessary, modifying the post-operative treatment for improved graft survival.

METHODS

Thirty cases registered for penetrating keratoplasty were worked up for routine systemic and ophthalmic criteria. A full-thickness diseased cornea was subjected to histopathology after suitable staining and fixation, including electron microscopic and immunohistochemical studies where possible.

RESULTS

The ages ranged from four to 60 years. The majority (26%) were in the age group of 31-40 years. The most frequent causes of corneal pathology that underwent keratoplasty include post-traumatic corneal scarring (40%), followed by pseudophakic bullous keratopathy (16.7%). In almost all cases, the histopathology confirmed the existing clinical diagnosis. Histopathology helped to confirm one doubtful case of Fuchs' dystrophy and to contradict one clinical diagnosis of pseudophakic bullous keratopathy, which turned out to be epithelization of the anterior chamber.

CONCLUSION

The results underline the significance of the histopathological study of these corneal conditions to increase the post-surgical survival of the corneal graft.

Effects of Descemet Stripping Automated Endothelial Keratoplasty on Corneal Densitometry of Cases with Long-Standing Pseudophakic Bullous Keratopathy

Purpose

To quantify the effects of Descemet stripping automated endothelial keratoplasty (DSAEK) on corneal clarity and densitometry of patients with long-standing pseudophakic bullous keratopathy (PBK) complicated with subepithelial fibrosis.

Methods

Thirty-four eyes with PBK complicated with corneal edema for more than 6 months and subepithelial fibrosis were enrolled. All subjects underwent complete ophthalmic examination and corneal densitometry module of Pentacam HR, before and 1, 3, and 6 months after DSAEK.

Results

Thirteen patients were excluded due to postoperative complications or missed to follow-up visits. Finally, twenty-one patients' data were analyzed. Corneal densitometry measures significantly decreased in all three layers (anterior, central, and posterior) 3 and 6 months after surgery compared to preoperative values; however, the differences did not reach statistical significance in the 1st month. Moreover, densitometry measurements were significantly lower at month 6 compared to month 1, but not at month 3 compared to month 1. Corneal densitometry of the anterior layer was significantly higher than central and posterior layers in 2 mm and 6 mm zones preoperatively and at all postoperative visits. Corneal light backscatter of each three layers was not statistically different between 0-2 mm and 2-6 mm in all pre- and postoperative visits.

Conclusions

Corneal densitometry in cases of PBK begins to improve after DSAEK in different layers in a slow and continued trend which takes up to 6 months for an effect to be seen. Interestingly, this improvement is possible even in complicated corneas with long-standing edema. Hence, corneal densitometry can be used as an objective method for quantification of the outcome of DSAEK in complicated cases of PBK.

Etiology and outcome of penetrating keratoplasty in bullous keratopathy post-cataract surgery vs post-glaucoma surgery

PURPOSE

To investigate the causes of bullous keratopathy (BK) in the Korean population and analyze the results of penetrating keratoplasty (PK) in BK eyes associated with the top two causes: pseudophakic bullous keratopathy (PBK) and glaucoma surgery-associated BK (GBK).

METHODS

Medical records were reviewed of patients diagnosed with BK at a tertiary referral center between 2010 and 2020. The predisposing conditions, clinical characteristics and therapeutic outcomes after PK were analyzed and compared.

RESULTS

Of total 340 BK eyes, 70% (238 eyes) were associated with ocular surgery; most commonly, cataract surgery (48%, 162 eyes) and glaucoma surgery/laser (21%, 70 eyes). The BK onset was faster following glaucoma surgery/laser (91.7 ± 94.4 months) than following cataract surgery (160.7 ± 138.0 months, p < 0.001). The median survival time of allografts was shorter in GBK than in PBK (24.0 vs 51.0 months, p = 0.020). Best-corrected logMAR visual acuities were lower in GBK than in PBK after PK (1.4 ± 0.7 vs 0.9 ± 0.6, p = 0.017 at one year; 1.8 ± 0.7 vs 1.1 ± 0.8, p = 0.043 at three years).

CONCLUSIONS

Intraocular surgery is the major predisposing condition of BK in Korea. GBK developed earlier and its therapeutic outcome was poorer, compared to PBK.

Ability of routinely collected clinical factors to predict good visual results after primary Descemet membrane endothelial keratoplasty: a cohort study

BACKGROUND

A comprehensive analysis of routinely collected pre/perioperative demographic/clinical factors that could predict final visual acuity after primary Descemet membrane endothelial keratoplasty (DMEK) has not been conducted previously.

METHODS

A retrospective monocenter cohort study was performed with consecutive patients with Fuchs endothelial corneal dystrophy (FECD) who underwent DMEK or triple-DMEK (DMEK combined with cataract surgery) in 2016-2020 in a French tertiary-care hospital. DMEK-only patients were pseudophakic. Patients were followed for 12 months. Surgery was considered successful when 12-month best-corrected visual acuity (BCVA) was ≤0.1 logMAR (≥0.8). Exploratory multivariate analysis was conducted with the following routinely collected variables to determine their ability to predict 12-month BCVA: patient age and sex; graft donor age; triple DMEK; preoperative values of BCVA, endothelial cell density (ECD), central corneal thickness (CCT), and mean anterior keratometry; and rebubbling.

RESULTS

Of 100 eyes (100 patients; mean age, 72 years; 61% female), 81 achieved a 12-month BCVA of ≤0.1 logMAR. Logistic regression analysis showed that older age was a significant prognosticator for 12-month BCVA > 0.1 logMAR (Odds Ratio = 0.914, 95% confidence intervals = 0.846-0.987; p = 0.02).

CONCLUSIONS

An older age associated with worse visual acuity outcomes after DMEK. This was confirmed by our analysis of the literature and supports the notion that DMEK should be conducted without delay once symptoms appear. Patient sex, donor age, triple-DMEK, and anterior keratometry also did not predict final BCVA in the literature. Preoperative CCT, ECD, and BCVA, and rebubbling occasionally appear in the literature as BCVA predictors, possibly reflecting an underlying ECD-BCVA axis.

Inadvertent retention of Descemet membrane after penetrating keratoplasty for pseudophakic bullous keratopathy

A retained Descemet membrane pertains to a type of retrocorneal membrane—a well-known yet rare complication of penetrating keratoplasty. We present a case of retained Descemet membrane after penetrating keratoplasty for pseudophakic bullous keratopathy. A 71-year-old woman presented to the ophthalmology clinic for loss of visual acuity. The previous year she had undergone phacoemulsification on both eyes, resulting in pseudophakic bullous keratopathy in the right eye; an uneventful penetrating keratoplasty was performed on the affected eye. The following day at follow-up, an undulated retrocorneal membrane was discovered on slit-lamp examination: corresponding to a retained Descemet membrane. A satisfactory descemetorhexis was performed. Timely diagnosis and intervention allowed for a remarkable outcome, with a best-corrected visual acuity of 20/50 OD with contact lens use.

Superficial Keratectomy: A Review of Literature

Superficial keratectomy (SK) is the manual dissection of the superficial corneal layers (epithelium, Bowman's layer, and sometimes superficial stroma). SK is done using a surgical blade or diamond burr. Some surgeons use intraoperative mitomycin C 0.02% or amniotic membrane transplantation to improve surgical outcomes. This literature review shows that SK remains an effective method for different indications, including tissue diagnosis, excision of corneal degenerations, dystrophies, scarring, recurrent corneal erosions, and retained corneal foreign body.

Amniotic Membrane Transplantation for Persistent Epithelial Defects and Ulceration due to Pseudomonas Keratitis in a Rabbit Model

Purpose

The use of amniotic membrane has been suggested in the treatment of infectious keratitis for its intrinsic anti-infective properties probably mediated by its anti-inflammatory effects. The aim of this study was to investigate the effect of amniotic membrane transplantation (AMT) along with ciprofloxacin to cure the primary stages of Pseudomonas keratitis.

Methods

In total, 28 rabbits were selected and divided in four groups as follows: group 1 as control, group 2 with amniotic membrane, group 3 with ciprofloxacin, and group 4 with amniotic membrane combined with ciprofloxacin. About 0.05 cc suspension of Pseudomonasaeruginosa, 27853 ATCC was injected into corneal stroma.

Results

The results showed groups of AMT, AMT + ciprofloxacin, and ciprofloxacin had 0% perforation while the control group had 85.6%. Average infiltration of 5.5 mm was observed in ciprofloxacin group, 5 mm in AMT + ciprofloxacin group, 24 mm in AMT group, and finally 23.75 mm for control. Amniotic membrane showed to be effective in prevention of cornea perforation as well as remission of Pseudomonas keratitis. There was no significant difference between ciprofloxacin groups in comparison with ciprofloxacin + AMT group. However, regarding the anti-inflammatory effect, the process of improvement of inflammation in ciprofloxacin + AMT group was faster.

Conclusion

Transplantation of amniotic membrane in the primary stages of Pseudomonas keratitis treatment remarkably prevents the disease and it can be used to control its process.

Visual Outcome of Combined Descemet Stripping Endothelial Keratoplasty and Sutured Scleral Fixated Intraocular Lens in Endothelial Decompensation with Coexistent Aphakia or Intra Ocular Lens Subluxation

Purpose To elucidate visual outcome of patients after combined Descemet stripping endothelial keratoplasty (DSEK) with scleral fixated intra ocular lens (SFIOL) implantation in patients of endothelial decompensation with coexistent aphakia or lens subluxation.

Materials and Methods A prospective interventional study of combined DSEK with sutured SFIOL in the patients who have undergone surgery at our center over 6-month follow-up period. Preoperative visual acuity and slit lamp findings were documented. Postoperative follow-up was done at days 1, 3, and 7 subsequently, months 1 and 3, and thereafter monthly till the sixth month.

Results Mean age of the patients was 60.47 years. Six patients had aphakic bullous keratopathy, while 11 patients had pseudophakic bullous keratopathy with subluxated posterior chamber IOL (PCIOL). Preoperative visual acuity ranged from hand movements close to face (LogMar 2.4) with accurate projection of rays to 1/60 (LogMar 2) due to existing corneal edema and aphakia. Postoperatively uncorrected visual acuity at 6 months improved up to 6/36 (LogMar 0.8) in all cases. There was gradual improvement in corneal clarity and compactness during the follow-up. A good donor tissue endothelial count and an adequate IOP control were vital prognostic factors for the successful outcome.

Conclusion This novel surgical merger reduces the complications of lenticule dislocation into vitreous and repeated surgeries and shows results akin to when performed in a staged manner.

Descemet-stripping automated endothelial keratoplasty with intrascleral haptic-fixated intraocular lens in a sequential vs simultaneous approach

PURPOSE

To compare the outcomes of Descemet-stripping automated endothelial keratoplasty (DSAEK) with intrascleral haptic-fixated intraocular lens (IOL) in a sequential and simultaneous approach.

SETTING

Tertiary eyecare center.

DESIGN

Prospective randomized comparative study.

METHODS

Patients with aphakic or complicated pseudophakic bullous keratopathy visiting a tertiary eyecare center were included in the study. A total of 40 patients were randomized into 2 groups of 20 each. Group 1 had subjects who underwent scleral-fixated IOL (SF IOL) implantation by intrascleral haptic fixation technique, followed by DSAEK (sequential procedure) with an interval of at least 3 months. Group 2 (simultaneous) had subjects who underwent DSAEK with SF IOL as a combined procedure. Graft survival, endothelial cell loss (ECL), corrected distance visual acuity (CDVA), and need for any intervention such as rebubbling were evaluated for both the groups at the end of 6 months.

RESULTS

At 6 months, the sequential group had significantly better CDVA of 0.62 ± 0.17 logMAR compared with 0.87 ± 0.19 logMAR in the simultaneous group (P = .002). Group 1 had significantly better overall cumulative graft survival (100% vs 60%, P = .002), significantly lower ECL (P = .006), lesser mean central corneal thickness (P = .03), and significantly thinner donor lenticule (P = .009). Rebubbling rate was significantly higher in Group 2 (P = .025). The mean hyperopic shift was significantly more in Group 2 (P = .02).

CONCLUSION

The sequential procedure of SF IOL followed by DSAEK has better visual outcomes and graft survival when compared with simultaneous procedure in cases of aphakic or complicated pseudophakic bullous keratopathy.

Predisposing Factors for Severe Complications after Cataract Surgery: A Nationwide Population-Based Study

We conducted a retrospective group study to evaluate the potential systemic risk factors for major postoperative complications of cataract surgery. Individuals diagnosed with (n = 2046) and without (n = 8184) serious complications after cataract surgery were matched 1:4 for age, sex, and index date obtained using Taiwan’s National Health Insurance Research Database. The outcome was defined as at least one new inpatient or outpatient diagnosis of systemic disease one year before the index date. The effect of demographic data on postoperative complications was also analyzed in the multivariable model. Data were analyzed using univariate and multivariate conditional logistic regression models to calculate odds ratios (ORs) and 95% confidence intervals of the risk of developing serious complications. After the entire study interval, the major postoperative complications of cataract surgery were associated with the following systemic diseases: hypertension (adjusted OR (aOR) = 2.329, p < 0.001), diabetes mellitus (aOR = 2.818, p < 0.001), hyperlipidemia (aOR = 1.702, p < 0.001), congestive heart failure (aOR = 2.891, p < 0.001), rheumatic disease (aOR = 1.965, p < 0.001), and kidney disease needing hemodialysis (aOR = 2.942, p < 0.001). Additionally, demographic data including old age, higher urbanization level, higher level of care, and more frequent inpatient department visits were associated with a higher rate of postoperative complications. In conclusion, metabolic syndrome, chronic heart failure, end-stage renal disease, rheumatic disease, older age, and frequent inpatient department visits are correlated with the development of severe postoperative complications of cataract surgery. Therefore, cataract surgery patients should be informed about a higher possibility of postoperative complications.

Fabrication and Characterization of Silk Fibroin-Based Nanofibrous Scaffolds Supplemented with Gelatin for Corneal Tissue Engineering

Tissue engineering is a promising approach to overcome the severe worldwide shortage of healthy donor corneas. In this work, we have developed a silk-gelatin composite scaffold using electrospinning and permeation techniques to achieve the properties comparable to cornea analog. In particular, we present the fabrication and comparative evaluation of the novel gelatin sheets consisting of silk fibroin nanofibers, which are prepared using silk fibroin (SF) (in formic acid) and SF (in aqueous) electrospun scaffolds, for its suitability as corneal stromal analogs. All the fabricated samples were treated with ethanol vapor (T) to physically crosslink the silk nanofibers. Micro/nano-scale features of the fabricated scaffolds were analyzed using scanning electron microscopy micrographs. Fourier transform infrared spectroscopy revealed characteristic peaks of polymeric functional groups and modifications upon ethanol vapor treatment. Transparency of the scaffolds was determined using UV-visible spectra. Among all the fabricated samples, the gelatin-permeated SF (in formic acid; T) scaffold showed the highest level of transparency, i.e., 77.75 ± 2.3%, which is similar to that of the native cornea (∼70%-90% [variable with age group]) with healthy acute vision. Contact angle of the samples was studied to estimate the hydrophilicity of the scaffolds. All the scaffolds except non-treated SF (in aqueous; NT) were found to be significantly stable up to 14 days when incubated in phosphate buffered saline at 37°C. Treated samples showed significantly better stability, both physically and microscopically, in comparison to nontreated samples. Proliferation and viability assays of rabbit corneal fibroblast cells (SIRC) and mouse fibroblast cells (L929 RFP) when cultured on fabricated scaffolds revealed remarkable cellular compatibility with gelatin-permeated SF (in formic acid; T) scaffolds compared to SF (in aqueous; T). Unlike other reports in the existing literature, this work presents the design and development of a nanofibrous silk-gelatin composite that exhibits acceptable transparency, cellular biocompatibility, as well as improved mechanical stability comparable to that of native cornea. Therefore, we anticipate that the fabricated novel scaffold is likely to be a good candidate for corneal tissue construct. Moreover, among the fabricated scaffolds, the outcomes depict gelatin-permeated SF (in formic acid; T) composite scaffold to be a better candidate as a corneal stromal analog that carries properties of both the silk and gelatin, i.e., optimal transparency, better stability, and enhanced cytocompatibility.

The ROCK Inhibitor Ripasudil Shows an Endothelial Protective Effect in Patients With Low Corneal Endothelial Cell Density After Cataract Surgery

Purpose

In the field of regenerative medicine, Rho kinase inhibitors (ROCK inhibitors) show a protective effect on the corneal endothelium and promote effective healing in acute surgical wounds. In this study, we investigated the effectiveness of eyedrops containing ripasudil, a ROCK inhibitor approved in Japan for therapeutic use for glaucoma.

Methods

In this retrospective observational study, 13 glaucoma patients (16 eyes) were treated with 0.4% ripasudil eyedrops twice a day after cataract surgery. The control group comprised 13 patients (17 eyes). The averaged corneal endothelial cell density from one central and four paracentral points was <1500/mm2 (range, 527 to 1439/mm2).

Results

The mean rate of increase in the thinnest corneal thickness one week after surgery was 1.25% in the ripasudil group, which was significantly lower than the 5.97% increase observed in the control group (P = 0.0037). The mean endothelial cell density loss 90 to 120 days after surgery, excluding bullous keratopathy patients for whom measurements were not possible was -4.5% in the ripasudil group, which was significantly lower than in control group (14.1%; P = 0.0003).

Conclusions

The results suggest that ripasudil may help maintain corneal endothelial functional integrity and reduce cell loss after cataract surgery in patients with low corneal endothelial cell density, suggesting that it may be more broadly useful for protection of the corneal endothelium after intraocular surgery.

Translational Relevance

The clinically approved ROCK inhibitor ripasudil formulated as an eye drop for glaucoma has a corneal endothelial protective effect in cataract surgery for patients with low corneal endothelial cell density.

[Evaluation of aqueous cytokine levels in eyes with Fuchs endothelial corneal dystrophy and bullous keratopathy]

PURPOSE

To evaluate cytokine levels in the aqueous humor (AH) of patients with Fuchs endothelial corneal dystrophy (FECD) and bullous keratopathy (BK).

MATERIAL AND METHODS

The study included 74 patients (74 eyes). The first group consisted of 31 patients (72.7±9.2 years) with FECD; the second group included 35 patients (72.4±9.1 years) with BK. The control group comprised 8 patients (74.3±4.1 years) with immature cataract. Before surgery, patients underwent pachymetry of the central cornea (RTvue-100 OCT, Optovue, USA). Patients of groups 1 and 2 underwent endothelial keratoplasty (DSAEK or DMEK), or penetrating corneal transplantation. Patients of the control group underwent phacoemulsification with implantation of intraocular lens. The initial stage of the surgery involved AH sample collection for evaluation of cytokine levels (IL-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12(p70), IL-13, IL-17, G-CSF, GM-CSF, IFNγ, MCP-1, MIP-1β and TNF-α) by fluorescent flow cytometry using the Bio-Plex Pro Human Cytokine Panel, 17-plex (Bio-Rad, USA).

RESULTS

Multiplex analysis of the AH content did not show any statistically significant differences in cytokine levels between decompensated FECD and BK eyes. The levels of IL-6, IL-8, GM-CSF, IFNγ, MCP-1, MIP-1β were significantly elevated in FECD and BK eyes compared with healthy control. An insignificant deviation of IL-4 and IL-13 levels was detected in FECD and BK eyes compared with healthy controls. There were no significant differences in IL-1β and TNF-α (indicators of acute inflammation) between the study groups.

CONCLUSION

The obtained data confirm that FECD and BK are associated with disruption of ocular immune privilege that leads to chronic local inflammation, which in turn causes remodeling of the corneal tissues resulting in fibrosis.

"Chopper Shield" Technique to Protect Corneal Endothelium During Phacoemulsification Surgery for Rock Hard Cataracts

Purpose

To describe an innovative technique of using a chopper as a shield for preventing mechanical corneal endothelial trauma that can occur during the phacoemulsification of brunescent cataracts.

Methods

This prospective study included patients with hard cataracts (grade nuclear opalescence 4 and above on LOCS III) who underwent phacoemulsification surgery. The chopper shield technique was performed in 48 eyes of 44 patients. The technique entailed placing the chopper horizontally as a shield anterior to the emulsifying nuclear fragment between the phaco tip and corneal endothelium to prevent nucleus fragments from coming into contact with the corneal endothelium. Outcome measures included cumulative dissipated energy (CDE), corneal edema (day one), CCT (assessed at one day, one week, and one month), and endothelial cell density assessed at three months.

Results

Of the 48 eyes included in the study, 23 were males and 25 were females (mean age: 70.02±5.98years). Preoperatively, mean central corneal thickness (CCT) was 529.62±21.70 microns, and endothelial cell counts were 2258.76±182.22 cells per mm². Postoperatively on day one, CCT increased to 563.93±24.53 microns, a 6.47% increase from preoperative central corneal thickness. CCT became 534.83±22.64 microns on postoperative day seven, a 0.98% increase from preoperative CCT. Endothelial cell loss was 6.77% at three months from the day of surgery.

Conclusion

The chopper shield technique offers continuous protection to the corneal endothelium by minimizing endothelial cell loss during phacoemulsification of dense nuclear cataracts.

Alternative Indications for Corneal Crosslinking

ABSTRACT

Corneal crosslinking (CXL) is the current mainstay treatment for progressive keratoconus. In the past 15 years, a variety of other indications have been tested. A systematic review was conducted to examine these alternative indications for CXL. In total, of 143 papers on crosslinking as a treatment for infectious keratitis, bullous keratopathy, pellucid marginal degeneration, post- laser in situ keratomileusis (LASIK) ectasia, and as a way to improve vision either on its own or in combination with other interventions were included. Post-LASIK ectasia is a definite indication for crosslinking. Surprisingly, only limited research has been performed on pellucid marginal degeneration, with no randomized trials available to date. Other interesting applications are the combined use of refractive lasers and crosslinking for suspicious or ectatic corneas and crosslinking as a standalone intervention for minor refractive errors. CXL might offer a solution for refractory bacterial keratitis. In bullous keratopathy, it seems to offer only a transient benefit.

The visual outcomes and complications of manual small incision cataract surgery and phacoemulsification: long term results

Objective: To compare visual outcomes and complications between manual small incision cataract surgery (MSICS) and phacoemulsification.

Methods: A retrospective study was conducted in the tertiary care center. A total of 1281 cases underwent manual small incision cataract surgery and phacoemulsification from January 2014 to December 2016. The postoperative best corrected visual acuity (BCVA) along with the rates of complications were compared between both groups.

Results: Five hundred and twenty-one patients (40.67%) and 760 patients (59.33%) were subjected by staff members and residents, respectively. Altogether, 689 cases (53.79%) were subjected to MSICS technique and 592 cases (46.21%) to phacoemulsification. The MSICS group had significantly harder cataract (cataract grading ≥ 4+ :31.64% vs. 7.77%; p<0.001). One month postoperatively, good visual outcome (BCVA ≥ 6 /18) in the phacoemulsification group was higher than that in the MSICS group (86.33% vs. 72.12%, p<0.001). The risk factor for poor outcome (post-operative BCVA < 6 /60 in both groups) was the presence of associated ocular pathologies. The intraoperative and perioperative complications rates were higher in the MSICS group (16.55% vs. 6.6%, p<0.001). The most common complications were hyphema (4.35%), posterior capsule ruptures (4.21%), and prolapsed iris (3.05%). Long-term postoperative complication rates were higher in the phacoemulsification group (9.29% vs. 21.28%, p<0.001). The most common complication was posterior capsule opacity (8.71% vs. 20.44%, p<0.001). Pseudophakic bullous keratopathy (PBK) was similar in both groups (0.29% vs. 0.17%, p=1.00).

Conclusion: The number of patients who had experienced good visual outcomes was higher in the phacoemulsification group. However, for both groups, no significant differences were found on the long-term complication rate.

Review on the Use of Topical Ocular Hypertonic Saline in Corneal Edema

PURPOSE

To review the effectiveness of topical ocular hypertonic saline in corneal edema.

METHODS

Online literature search of published articles on the effectiveness of topical hypertonic saline in corneal edema, bullous keratopathy (BK), and other associated corneal conditions in humans was performed on April 16, 2020.

RESULTS

A total of 16 articles were reviewed after curation by the authors for relevance, with 4 randomized control trials, 6 prospective studies, 4 retrospective studies, and 2 case reports. Efficacy of hypertonic saline eye drops varied widely, depending on the specific corneal disorder being treated. Six of the studies involved BK (edema involves epithelium), 2 in corneal edema limited to the stroma, 5 in Fuchs dystrophy, 3 in filamentary keratitis (the presence of filaments attached to corneal epithelium), 2 in recurrent corneal erosion, and 1 in jellyfish stings. There was limited efficacy for hypertonic saline in BK, whereas clinical improvement was noted in most studies for corneal edema without epithelial involvement, especially if associated with Fuchs dystrophy or corneal hydrops in keratoconus. Hypertonic saline also seems to be beneficial for other corneal disorders, such as filamentary keratitis and jellyfish stings, but not in recurrent corneal erosion. Adverse effects from topical hypertonic saline include a mild stinging or burning sensation, with no serious complications having been reported.

CONCLUSIONS

Topical ocular hypertonic saline seems to be a safe and effective treatment in the management of less severe forms of corneal edema and other corneal disorders such as filamentary keratitis.

Iatrogenic corneal diseases or conditions

Any prescribed or self-administered therapy carries inherent risks of secondary adverse events. While the volume of treatments being administered through healthcare systems has been increasing, scientific advancements in our understanding of the mechanisms of pharmaceutical side effects and complications from procedures now allow us to reduce the risk of non-intentional damage to ocular health. This review summarizes the most common and leading causes of iatrogenic visual impairment, corneal diseases, and conditions that present in a general ophthalmologic practice, including a comprehensive analysis of their pathophysiology and recommendations for management and prophylaxis.Iatrogenic corneal diseases and conditions can arise from topical drugs, contact lens use, eye surgeries and procedures, systemic drugs, non-ophthalmological events, and cosmetic procedures. Topical and systemic drugs may disturb tear film homeostasis or result in ocular surface deposits. The use of ill-fitted contact lenses can trigger eye discomfort and poor hygiene conditions that can predispose to severe infections. Procedures to the eye may result in a variety of anatomical and functional complications that ophthalmologists should be aware of how to avoid or at least be prepared to manage if they occur. Even non-ophthalmological events such as non-invasive ventilation, radiation therapies and, immune-based conditions, or cosmetic procedures such as eyelash growth and fillers, can result in unwanted damage to the ocular surface.