Intraoperative optical coherence tomography guided iris stromal cyst treatment with absolute alcohol injection.

Purpose: To report on the utility of intraoperative optical coherence tomography (iOCT) in the treatment of a traumatic iris cyst with aspiration and alcohol injection. Observations: A 61-year-old male, with a past ocular history of a left corneoscleral laceration in 1982, presented with gradual onset of blurring of vision in 2021. Examination revealed a large iris stromal cyst. He subsequently underwent iOCT guided iris stromal cyst aspiration and absolute alcohol injection. Conclusions and importance: Our case demonstrated the efficacy of iOCT to aid in direct visualization and safe guidance of the alcohol into the iris cyst, reducing the risk of collateral damage.

The Impact of the COVID-19 Pandemic on Corneal Transplantation in Brazil.

PURPOSE: The purpose of this study was to evaluate the impact of the coronavirus disease 2019 pandemic on corneal transplantation (CT) in Brazil. METHODS: Data from patients who underwent CT at the Hospital Oftalmológico de Sorocaba (HOS), Brazil, were analyzed. National and state numbers of keratoplasties, patients added to the CT waiting list, and total patients on the waiting list were also obtained. Baseline prepandemic (from January 1, 2019, to March 31, 2020) data were compared with 2 time frames of the coronavirus disease 2019 pandemic: elective CT suspension period (between April 1, 2020, and September 31, 2020) and after elective CT resumption (between October 1, 2020, and April 30, 2021). RESULTS: Despite elective CT resumption after the moratorium, the monthly CT rates did not return to baseline at HOS (-14.7%, P = 0.007), São Paulo state (-19.1%, P = 0.001), or Brazil (-30.1%, P < 0.001). The waiting list increased significantly regionally (P < 0.001) and nationally (P < 0.001). Among optical keratoplasties performed at HOS after resuming elective CTs, the proportion of endothelial keratoplasties declined from 38.2% to 30.0% (P < 0.001), whereas penetrating keratoplasties increased from 33.2% to 39.5% (P < 0.001) when comparing with prepandemic data. CONCLUSIONS: Keratoplasty numbers dropped significantly locally, regionally, and nationally. Hence, the CT waiting lists had a progressive increase, with significant long-term implications. An estimated increment on monthly CT rates of approximately 34% in São Paulo state, and 91% in Brazil, is required for the CT waiting list to get back to prepandemic numbers over the next 2 years.

Trends in Corneal Transplantation in a Tertiary Hospital in Brazil.

PURPOSE: The purpose of this study was to analyze the evolving trends of surgical techniques and indications of corneal transplantation (CT) at a tertiary hospital in Brazil. METHODS: The medical records of all patients who underwent CT at the Hospital Oftalmológico de Sorocaba (Sorocaba Eye Hospital) from the Banco de Olhos de Sorocaba (Sorocaba Eye Bank) group in Sorocaba, Brazil, from January 1, 2012, to December 31, 2019, were analyzed. Data regarding age, sex, transplant indication, and surgical technique were collected. RESULTS: A total of 16,250 CTs were performed. There was a statistically significant decreasing trend of keratoconus-related CT ( P < 0.0001), with rates dropping from 41.7% among all CTs in 2012 to 25.5% in 2019. Penetrating keratoplasty, anterior lamellar keratoplasty, and endothelial keratoplasty (EK) accounted for 59.3%, 27.1%, and 7.8% of the CTs performed in 2012 and 33.3%, 16.4%, and 39.9% in 2019, respectively. A statistically significant decreasing trend was observed for penetrating keratoplasty ( P < 0.0001) and anterior lamellar keratoplasty ( P < 0.0001), whereas EK showed a statistically significant increasing trend during the period ( P < 0.0001). Among EKs, Descemet membrane EK increased statistically significantly from 12.8% in 2012 to 74.4% in 2019 ( P < 0.0001). CONCLUSIONS: This study shows relevant evolving trends in indications and preferred CT techniques in a tertiary hospital in Brazil.

Gene-Based Therapeutics for Acquired Retinal Disease: Opportunities and Progress.

Acquired retinal diseases such as age-related macular degeneration and diabetic retinopathy rank among the leading causes of blindness and visual loss worldwide. Effective treatments for these conditions are available, but often have a high treatment burden, and poor compliance can lead to disappointing real-world outcomes. Development of new treatment strategies that provide more durable treatment effects could help to address some of these unmet needs. Gene-based therapeutics, pioneered for the treatment of monogenic inherited retinal disease, are being actively investigated as new treatments for acquired retinal disease. There are significant advantages to the application of gene-based therapeutics in acquired retinal disease, including the presence of established therapeutic targets and common pathophysiologic pathways between diseases, the lack of genotype-specificity required, and the larger potential treatment population per therapy. Different gene-based therapeutic strategies have been attempted, including gene augmentation therapy to induce in vivo expression of therapeutic molecules, and gene editing to knock down genes encoding specific mediators in disease pathways. We highlight the opportunities and unmet clinical needs in acquired retinal disease, review the progress made thus far with current therapeutic strategies and surgical delivery techniques, and discuss limitations and future directions in the field.

Comparative Study of Long-term Graft Survival Between Penetrating Keratoplasty and Deep Anterior Lamellar Keratoplasty.

PURPOSE: Endothelial failure and immunological graft rejection remain long-term complications leading to late graft failure in penetrating keratoplasty (PK). Deep anterior lamellar keratoplasty (DALK) has emerged as a viable alternative that enables preservation of the host's endothelial cells to eliminate risks of endothelial rejection and failure. The aim of this study was to compare long-term graft survival between PK and DALK. DESIGN: Retrospective clinical cohort study. METHODS: All consecutive primary grafts of DALKs (n = 362) and PKs (n = 307) performed for optical indications in a tertiary eye center from the ongoing, prospective Singapore Corneal Transplant Study. Ten-year graft survival outcomes were compared. Cases in which endothelial pathologies were diagnosed were excluded, as DALK was not performed for such cases. Main outcome measurements were mean graft survival rate. RESULTS: The survival rate for PK was 94.4%, 80.4%, and 72.0% at 1, 5, and 10 years, respectively; and 95.8%, 93.9%, and 93.9% at 1, 5, and 10 years, respectively, for DALK (P = .001). Patients who underwent PK developed more complications of glaucoma (29.3% vs. 11.6%, respectively; P < .001), allograft rejection (16.6% vs. 1.7%, respectively; P < .001), epithelial problems (10.4% vs. 5.5%, respectively; P = .018), and nonimmunological failure (7.8% vs. 1.9%, respectively; P < .001), compared to DALK. Rates of graft failure attributable to rejection (36.7% vs. 5.9%, respectively; P = .015) and endothelial failure (36.7% vs. 5.9%, respectively; P = .015) were lower in DALK. CONCLUSIONS: The 10-year graft survival for primary DALK was superior to that for PK for corneal pathologies with functional endothelium. Primary DALK resulted in fewer post-operative complications and lower rates of graft rejection and failure. This study strengthens the case in favor of performing DALK over PK when possible.

Complications of small incision lenticule extraction.

The procedure of small incision lenticule extraction (SMILE) was introduced in 2011, and since then there has been an increase in the number of cases undergoing this procedure worldwide. The surgery has a learning curve and may be associated with problems in the intraoperative and postoperative periods. The intraoperative problems during SMILE surgery include the loss of suction, the occurrence of altered or irregular opaque bubble layer and black spots, difficulty in lenticular dissection and extraction, cap perforation, incision-related problems, and decentered ablation. Most of the postoperative problems are similar as in other laser refractive procedures, but with decreased incidence. The identification of risk factors, clinical features, and management of complications of SMILE help to obtain optimum refractive outcomes.

Pharmaceutical modulation of the proteolytic profile of Transforming Growth Factor Beta induced protein (TGFBIp) offers a new avenue for treatment of TGFBI-corneal dystrophy.

Corneal dystrophies are a group of genetically inherited disorders with mutations in the TGFBI gene affecting the Bowman's membrane and the corneal stroma. The mutant TGFBIp is highly aggregation-prone and is deposited in the cornea. Depending on the type of mutation the protein deposits may vary (amyloid, amorphous powdery aggregate or a mixed form of both), making the cornea opaque and thereby decreases visual acuity. The aggregation of the mutant protein is found to be specific with a unique aggregation mechanism distinct to the cornea. The proteolytic processing of the mutant protein is reported to be different compared to the WT protein. The proteolytic processing of mutant protein gives rise to highly amyloidogenic peptide fragments. The current treatment option, available for patients, is tissue replacement surgery that is associated with high recurrence rates. The clinical need for a simple treatment option for corneal dystrophy patients has become highly essential either to prevent the protein aggregation or to dissolve the preformed aggregates. Here, we report the screening of 2500 compounds from the Maybridge RO3 fragment library using weak affinity chromatography (WAC). The primary hits from WAC were validated by 15N-HSQC NMR assays and specific regions of binding were identified. The recombinant mutant proteins (4th FAS-1 domain of R555W and H572R) were subjected to limited proteolysis by trypsin together with the lead compounds identified by NMR assays. The lead compounds (MO07617, RJF00203 and, BTB05094) were effective to delay/prevent the generation of amyloidogenic peptides in the R555W mutant and compounds (RJF00203 and BTB05094) were effective to delay/prevent the generation of amyloidogenic peptides in the H572R mutant. Thus the lead compounds reported here upon further validation and/or modification might be proposed as a potential treatment option to prevent/delay aggregation by inhibiting the formation of amyloidogenic peptides in TGFBI-corneal dystrophy.

Descemet Membrane Endothelial Keratoplasty With a Pull-Through Insertion Device: Surgical Technique, Endothelial Cell Loss, and Early Clinical Results.

PURPOSE: To describe a surgical technique for Descemet membrane endothelial keratoplasty (DMEK) using a pull-through, endothelium-in insertion device, the DMEK EndoGlide. We evaluated the endothelial cell loss (ECL) associated with the EndoGlide-DMEK (E-DMEK) technique in both ex vivo and prospective clinical studies. METHODS: The ex vivo study involved calcein acetoxymethyl staining and preparation of DMEK grafts, which were trifolded endothelium-in, loaded into the EndoGlide, pulled through, and unfolded in imaging dishes. Inverted fluorescent microscopy was performed, and ECL was quantified using trainable segmentation software. The prospective clinical series describes the outcomes of consecutive surgeries using the E-DMEK technique. Grafts were pulled through the EndoGlide with forceps and unfolded in the anterior chamber endothelium-down. Our main outcome measure was ECL in both studies. RESULTS: In the ex vivo study with 9 human donor corneas, mean ECL was 15.2% ± 5.4% (n = 9). In our clinical series of 69 eyes, leading indications for surgery were pseudophakic/aphakic bullous keratopathy (47.8%), previous failed grafts (23.2%), and Fuchs endothelial dystrophy (18.8%). Rebubbling and primary graft failure rates related to E-DMEK were 11.6% and 1.5%, respectively. Among eyes with at least 6 months of follow-up, mean preoperative endothelial cell density was 2772 (range 2457-3448) cells/mm, and postoperative endothelial cell density was 1830 (range 541-2545) cells/mm. Mean ECL was 33.6% (range 7.5-80.4; n = 32) at the 7.1 (range 6-11) months follow-up. CONCLUSIONS: The ex vivo and pilot clinical studies suggest that E-DMEK shows acceptable rates of ECL, with safe and promising early clinical outcomes.

Corneal remodelling and topography following biological inlay implantation with combined crosslinking in a rabbit model.

Implantation of biological corneal inlays, derived from small incision lenticule extraction, may be a feasible method for surgical management of refractive and corneal diseases. However, the refractive outcome is dependent on stromal remodelling of both the inlay and recipient stroma. This study aimed to investigate the refractive changes and tissue responses following implantation of 2.5-mm biological inlays with or without corneal collagen crosslinking (CXL) in a rabbit model. Prior to implantation, rotational rheometry demonstrated an almost two-fold increase in corneal stiffness after CXL. After implantation, haze gradually subsided in the CXL-treated inlays (p = 0.001), whereas the untreated inlays preserved their clarity (p = 0.75). In-vivo confocal microscopy revealed reduced keratocyte cell count at the interface of the CXL inlays at week 8. Following initial steepening, regression was observed in anterior mean curvature from week 1 to 12, being most prominent for the non-CXL subgroups (non-CXL: -12.3 ± 2.6D vs CXL: -2.3 ± 4.4D at 90 µm depth, p = 0.03; non-CXL: -12.4 ± 8.0D vs CXL: -5.0 ± 4.0D at 120 µm depth, p = 0.22). Immunohistochemical analysis revealed comparable tissue responses in CXL and untreated subgroups. Our findings suggest that CXL of biological inlays may reduce the time before refractive stabilization, but longer postoperative steroid treatment is necessary in order to reduce postoperative haze.

Corneal re-innervation following refractive surgery treatments.

Laser refractive surgery is one of the most performed surgical procedures in the world. Although regarded safe and efficient, it has side effects. All of the laser based refractive surgical procedures invoke corneal nerve injury to some degree. The impact of this denervation can range from mild discomfort to neurotrophic corneas. Currently, three techniques are widely used for laser vision correction: small incision lenticule extraction, laser-assisted keratomileusis in situ and photorefractive keratotomy. Each of these techniques affects corneal innervation differently and has a different pattern of nerve regeneration. The purpose of this review is to summarize the different underlying mechanisms for corneal nerve injury and compare the different patterns of corneal reinnervation.

Trinucleotide repeat expansion length as a predictor of the clinical progression of Fuchs' Endothelial Corneal Dystrophy.

PURPOSE: To determine if CTG18.1 TNR expansion length prognosticates the clinical progression of Fuchs' Endothelial Corneal Dystrophy (FECD). METHODS: This was a prospective cohort study. A total of 51 patients with newly diagnosed FECD were recruited and followed-up over a period of 12 years, from November 2004 to April 2016. Baseline clinical measurements included central corneal thickness (CCT), endothelial cell density (ECD) and CTG18.1 TNR expansion length from peripheral leukocytes, with yearly repeat measurements of CCT and ECD. A patient was defined to have experienced significant clinical progression and to have developed Threshold Disease if any of these criteria were fulfilled in either eye: a) CCT increased to >700µm, b) ECD decreased to <700 cells/mm2, or c) underwent keratoplasty for treatment of FECD. RESULTS: Patients were categorized as having at least one allele whose maximum allele length was equal to or greater than 40 repeats (L≥40, n = 22, 43.1%), or having both alleles shorter than 40 repeats (L<40). Threshold Disease rates at the 5-year time point were 87.5% for the L≥40 group and 47.8% for the L<40 group (p = 0.012). This difference narrowed and was no longer statistically significant at the 8-years (92.9% vs 78.9%, p = 0.278) and 10-years (92.9% vs 84.2%, p = 0.426) time points. CONCLUSIONS: L≥40 patients are at greater risk of FECD progression and development of Threshold Disease within the first 5 years following diagnosis.

Reshaping and Customization of SMILE-Derived Biological Lenticules for Intrastromal Implantation.

Purpose: To evaluate the feasibility of excimer laser reshaping of biological lenticules available after small incision lenticule extraction (SMILE). Methods: Fresh and cryopreserved SMILE-derived human lenticules underwent excimer laser ablation for stromal reshaping. The treatment effects in the lasered group were compared with the nonlasered group with respect to changes in surface functional groups (by Fourier transform infrared spectroscopy [FTIR]) and surface morphology (by scanning electron microscopy [SEM] and atomic force microscopy [AFM]). Ten SMILE-derived porcine lenticules, five nonlasered (107-µm thick, -6 diopter [D] spherical power) and five excimer lasered (50% thickness reduction), were implanted into a 120-µm stromal pocket of 10 porcine eyes. Corneal thickness and topography were assessed before and after implantation. Results: FTIR illustrated prominent changes in the lipid profile. The collagen structure was also affected by the laser treatment but to a lesser extent. SEM exhibited a more regular surface for the lasered lenticules, confirmed by the lower mean Rz value (290.1 ± 96.1 nm vs. 380.9 ± 92.6 nm, P = 0.045) on AFM. The lasered porcine lenticules were thinner than the nonlasered controls during overhydration (132 ± 26 µm vs. 233 ± 23 µm, P < 0.001) and after 5 hours in a moist chamber (46 ± 3 µm vs. 57 ± 3 µm, P < 0.001). After implantation, the nonlasered group showed a tendency toward a greater increase in axial keratometry (6.63 ± 2.17 D vs. 5.60 ± 3.79 D, P = 0.613) and elevation (18.6 ± 15.4 vs. 15.2 ± 5.5, P = 0.656) than the lasered group. Conclusions: Excimer laser ablation may be feasible for thinning and reshaping of SMILE-derived lenticules before reimplantation or allogenic transplantation. However, controlled lenticule dehydration before ablation is necessary in order to allow stromal thinning.

Predicative Factors for Corneal Endothelial Cell Migration.

PURPOSE: To characterize the effects of Descemet's stripping, Rho-associated protein kinase inhibitor Y-27632, and donor age on endothelial migration in human corneas maintained in ex vivo culture. METHODS: Twenty-eight cadaveric human corneas underwent ex vivo culture in either standard or Y-27632-supplemented culture medium for 14 days. The posterior surface of each cornea was manipulated to create two types of wounds: scratched wound--corneal endothelial cells (CECs) were denuded from the Descemet's membrane (DM) to leave behind a bare but intact DM; and peeled wound--both the DM and overlying CECs were stripped to leave behind bare corneal stroma. Endothelial migration was assessed via Trypan blue staining. Morphologic traits of CECs were assessed via Alizarin red microscopy and scanning electron microscopy. RESULTS: The CECs migrated preferentially over scratched wounds compared with peeled wounds. Y-27632 supplementation accelerated endothelial migration over scratched wounds. Endothelial migration decreased with advanced donor age for both wound types, regardless of exposure to Y-27632. Y-27632 supplementation resulted in a less rapid decline in endothelial migration for donors older than 50 years of age for scratched surfaces. Greater cell density and hexagonality was observed over scratched wounds compared with peeled wounds, regardless of Y-27632 supplementation. CONCLUSIONS: The presence of an intact DM, Y-27632 supplementation, and young donor age are factors that promote endothelial migration in an ex vivo human cornea culture model. The negative effect of age on endothelial migration can be mitigated by the presence of an intact DM and Y-27632 supplementation.

Signature microRNAs in human cornea limbal epithelium.

This study was aimed to identify the signature microRNAs, which regulate the biological processes of corneal epithelial progenitor cell (CEPC) homeostasis and regulation through characterizing the differential expression profile of microRNAs in human limbal epithelium containing adult CEPC versus central corneal epithelium without CEPC. MicroRNA microarray had identified 37 microRNAs enriched in human corneal epithelium. Among them, nine were significantly upregulated in limbal epithelium and one in central corneal epithelium after validation by TaqMan® real-time polymerase chain reaction. In addition to our previous finding of miR-143 and 145, the expression of miR-10b, 126, and 155 was localized in limbal epithelium (LE) (predominantly basal layers) by using locked nucleic acid-based in situ hybridization. Potential target genes were predicted by TargetScan Human v6.0 and compared to the reported human cornea epithelial gene profile GSE5543. Analyzed by web-based Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and DAVID Functional Annotation Bioinformatics Resources v6.7, the downregulated genes were involved in pathways of immune response and cellular protection, apoptosis, and cell movement whereas upregulated genes with cell survival, cell-matrix interaction, and cell-cell adhesion. We found a constant occurrence of miR-143, 145, and 155 in all KEGG pathways regulating limbal epithelial events. By Ingenuity Systems (IPA®) analysis, these microRNAs could cooperatively regulate cell growth and apoptosis via tumor necrosis factor activation and MYC repression. Our findings thus suggest a unique microRNA signature existing in human limbal epithelium and participating in CEPC homeostasis.

Absence of phenotype-genotype correlation of patients expressing mutations in the SLC4A11 gene.

PURPOSE: The purposes of this study were to describe the clinical characteristics of corneal patients with mutations in the SLC4A11 gene and to determine if these characteristics could be correlated with specific genetic mutations. METHODS: A retrospective case series review was conducted. Baseline demographic data, including gender, age at diagnosis of congenital hereditary endothelial dystrophy, family history, and pedigree information, were obtained. Information from clinical examination, including intraocular pressure, ultrasonic pachymetry, best spectacle-corrected visual acuity, axial length, and slit-lamp biomicroscopic evaluation, including corneal diameter and fundus examination, were also documented from the notes. History of corneal surgery was also recorded. Hearing loss was assessed by audiometry. Genetic analysis was performed by polymerase chain reaction amplification and sequencing. RESULTS: Seven patients were identified. Four of the seven had associated hearing loss; all of the patients had undergone or were awaiting penetrating keratoplasty to one or both eyes. No correlation could be reached between the ocular phenotype and the gene mutation in this small sample. Individuals with the same mutation had different degrees of hearing loss within their respective families. CONCLUSIONS: Corneal endothelial cells are more vulnerable to defects in the functional activity of SLC4A11 than cells of the striae vascularis of the inner ear. Both congenital hereditary endothelial dystrophy 2 and Harboyan syndrome have similar ocular phenotypes, ie, diffuse bilateral corneal edema present at birth or within the neonatal period; hence, audiometry must be performed to differentiate the two conditions.

Femtosecond laser-assisted endothelial keratoplasty: a laboratory model.

PURPOSE: To evaluate the ability of a 40-kHz femtosecond laser in performing posterior stromal ablation for endothelial keratoplasty. METHODS: Human corneoscleral rims were mounted on an artificial anterior chamber. After corneal pachymetry, the femtosecond laser was used to create a donor lenticule by using a variety of diameter ablations, 150 microm from the Descemet membrane. After ablation, the donor lenticule was peeled from the posterior surface and examined under light and scanning electron microscopy. Grading of ease of peeling and removing of the donor lenticule was assessed. RESULTS: The 40-kHz laser was able to produce effective dissection at low power in the posterior stroma. Modification of laser parameter settings was needed to improve the quality of stromal bed ablation. Double pass ablation of the bed significantly improved ease of peeling and removing of the donor lenticule. This was corroborated by smoother ablations on light and scanning electron microscopy. However, multiple pass ablations did not improve vertical rim dissections, which were satisfactory when single passes were used. CONCLUSIONS: Femtosecond laser-assisted endothelial keratoplasty is a viable alternative to microkeratome-assisted endothelial keratoplasty. Customized nomograms are needed for deep stromal ablation.

Primary graft failure after Descemet-stripping automated endothelial keratoplasty: clinico-pathological study.

PURPOSE: Descemet-stripping automated endothelial keratoplasty (DSAEK) is a selective tissue corneal transplantation procedure in which only the diseased endothelium and the Descemet membrane is replaced. Refractive and visual results have been encouraging with this procedure, but higher rates of primary graft failure have been noted. We herein report histopathologic and ultrastructural changes in 2 cases of primary graft failure after DSAEK. We are not aware of these features being reported previously. METHODS: Two cases of primary graft failure after DSAEK. One patient underwent DSAEK for Fuchs endothelial dystrophy and the other for pseudophakic bullous keratopathy. Both DSAEK procedures were uneventful. Postoperatively, there was no graft dislocation, but 1 patient had a nasal Descemet detachment that was reapposed with intracameral air. One month postoperatively, there was no improvement in the vision, and both patients had pronounced swelling of the recipient and donor corneas. Both patients underwent graft exchange. Both the recipient and donor corneal edema resolved. RESULTS: Histopathologic evaluation showed marked corneal edema and loss of endothelial cells. Ultrastructural evaluation showed only remnant endothelial cell membranes present in 1 sample devoid of any intracellular contents. Transmission electron microscopy showed the presence of extensively damaged keratocytes in the deep posterior stroma and also in the interface at the graft-host junction. CONCLUSIONS: These cases show widespread and irrecoverable endothelial and keratocyte damage in patients with primary graft failure after DSAEK.