Creating realistic anterior segment optical coherence tomography images using generative adversarial networks

AIMS

To develop a generative adversarial network (GAN) capable of generating realistic high-resolution anterior segment optical coherence tomography (AS-OCT) images.

METHODS

This study included 142 628 AS-OCT B-scans from the American University of Beirut Medical Center. The Style and WAvelet based GAN architecture was trained to generate realistic AS-OCT images and was evaluated through the Fréchet Inception Distance (FID) Score and a blinded assessment by three refractive surgeons who were asked to distinguish between real and generated images. To assess the suitability of the generated images for machine learning tasks, a convolutional neural network (CNN) was trained using a dataset of real and generated images over a classification task. The generated AS-OCT images were then upsampled using an enhanced super-resolution GAN (ESRGAN) to achieve high resolution.

RESULTS

The generated images exhibited visual and quantitative similarity to real AS-OCT images. Quantitative similarity assessed using FID scored an average of 6.32. Surgeons scored 51.7% in identifying real versus generated images which was not significantly better than chance (p value >0.3). The CNN accuracy improved from 78% to 100% when synthetic images were added to the dataset. The ESRGAN upsampled images were objectively more realistic and accurate compared with traditional upsampling techniques by scoring a lower Learned Perceptual Image Patch Similarity of 0.0905 compared with 0.4244 of bicubic interpolation.

CONCLUSIONS

This study successfully developed and leveraged GANs capable of generating high-definition synthetic AS-OCT images that are realistic and suitable for machine learning and image analysis tasks.

Design and Biocompatibility of a Novel, Flexible Artificial Cornea

Purpose

We sought to introduce the materials, design, and biocompatibility of a flexible and suturable artificial corneal device.

Methods

Single-piece, fully synthetic, optic-skirt design devices were made from compact perfluoroalkoxy alkane. The skirt and the optic wall surfaces were lined with a porous tissue ingrowth material using expanded polytetrafluoroethylene. Full-thickness macroapertures around the skirt perimeter were placed to facilitate nutrition of the recipient cornea. Material properties including the skirt's modulus of elasticity and bending stiffness, optic light transmission, wetting behavior, topical drug penetrance, and degradation profile were evaluated.

Results

The final prototype suitable for human use has a transparent optic with a diameter of 4.60 mm anteriorly, 4.28 mm posteriorly, and a skirt outer diameter of 6.8 mm. The biomechanical and optical properties of the device closely align with the native human cornea with an average normalized device skirt-bending stiffness of 4.7 kPa·mm4 and light transmission in the visible spectrum ranging between 92% and 96%. No optical damage was seen in the 36 devices tested in fouling experiments. No significant difference was observed in topical drug penetrance into the anterior chamber of the device implanted eye compared with the naïve rabbit eye.

Conclusions

The flexibility and biocompatibility of our artificial cornea device may offer enhanced tissue integration and decreased inflammation, leading to improved retention compared with rigid keratoprosthesis designs.

Translational Relevance

We have developed a fully synthetic, flexible, suturable, optic-skirt design prototype artificial cornea that is ready to be tested in early human feasibility studies.

Clinical Features and Treatment Outcomes of Carbapenem-Resistant Pseudomonas aeruginosa Keratitis

Importance

Evaluation of the microbiological diagnostic profile of multidrug-resistant Pseudomonas aeruginosa keratitis and potential management with rose bengal-photodynamic antimicrobial therapy (RB-PDAT) is important.

Objective

To document the disease progression of carbapenemase-resistant P aeruginosa keratitis after an artificial tear contamination outbreak.

Design, Setting, and Participants

This retrospective observation case series included 9 patients 40 years or older who presented at Bascom Palmer Eye Institute and had positive test results for multidrug-resistant P aeruginosa keratitis between January 1, 2022, and October 31, 2023.

Main Outcomes and Measures

Evaluation of type III secretion phenotype, carbapenemase-resistance genes blaGES and blaVIM susceptibility to antibiotics, and in vitro and in vivo outcomes of RB-PDAT against multidrug-resistant P aeruginosa keratitis.

Results

Among the 9 patients included in the analysis (5 women and 4 men; mean [SD] age, 73.4 [14.0] years), all samples tested positive for exoU and carbapenemase-resistant blaVIM and blaGES genes. Additionally, isolates were resistant to carbapenems as indicated by minimum inhibitory concentration testing. In vitro efficacy of RB-PDAT indicated its potential application for treating recalcitrant cases. These cases highlight the rapid progression and challenging management of multidrug-resistant P aeruginosa. Two patients were treated with RB-PDAT as an adjuvant to antibiotic therapy and had improved visual outcomes.

Conclusions and Relevance

This case series highlights the concerning progression in resistance and virulence of P aeruginosa and emphasizes the need to explore alternative therapies like RB-PDAT that have broad coverage and no known antibiotic resistance. The findings support further investigation into the potential effects of RB-PDAT for other multidrug-resistant microbes.

Automatic Classification of Slit-Lamp Photographs by Imaging Illumination

PURPOSE

The aim of this study was to facilitate deep learning systems in image annotations for diagnosing keratitis type by developing an automated algorithm to classify slit-lamp photographs (SLPs) based on illumination technique.

METHODS

SLPs were collected from patients with corneal ulcer at Kellogg Eye Center, Bascom Palmer Eye Institute, and Aravind Eye Care Systems. Illumination techniques were slit beam, diffuse white light, diffuse blue light with fluorescein, and sclerotic scatter (ScS). Images were manually labeled for illumination and randomly split into training, validation, and testing data sets (70%:15%:15%). Classification algorithms including MobileNetV2, ResNet50, LeNet, AlexNet, multilayer perceptron, and k-nearest neighborhood were trained to distinguish 4 type of illumination techniques. The algorithm performances on the test data set were evaluated with 95% confidence intervals (CIs) for accuracy, F1 score, and area under the receiver operator characteristics curve (AUC-ROC), overall and by class (one-vs-rest).

RESULTS

A total of 12,132 images from 409 patients were analyzed, including 41.8% (n = 5069) slit-beam photographs, 21.2% (2571) diffuse white light, 19.5% (2364) diffuse blue light, and 17.5% (2128) ScS. MobileNetV2 achieved the highest overall F1 score of 97.95% (CI, 97.94%-97.97%), AUC-ROC of 99.83% (99.72%-99.9%), and accuracy of 98.98% (98.97%-98.98%). The F1 scores for slit beam, diffuse white light, diffuse blue light, and ScS were 97.82% (97.80%-97.84%), 96.62% (96.58%-96.66%), 99.88% (99.87%-99.89%), and 97.59% (97.55%-97.62%), respectively. Slit beam and ScS were the 2 most frequently misclassified illumination.

CONCLUSIONS

MobileNetV2 accurately labeled illumination of SLPs using a large data set of corneal images. Effective, automatic classification of SLPs is key to integrating deep learning systems for clinical decision support into practice workflows.

Variations in irradiation energy and rose bengal concentration for photodynamic antimicrobial therapy of fungal keratitis isolates

The purpose is to assess the efficacy of rose bengal photodynamic antimicrobial therapy (PDAT) using different irradiation energy levels and photosensitizer concentrations for the inhibition of fungal keratitis isolates. Seven different fungi (Aspergillus fumigatus, Candida albicans, Curvularia lunata, Fusarium keratoplasticum, Fusarium solani, Paecilomyces variotii, and Pseudallescheria boydii) were isolated from patients with confirmed infectious keratitis. Experiments were performed in triplicate with suspensions of each fungus exposed to different PDAT parameters including a control, green light exposure of 5.4 J/cm2, 2.7 J/cm2 (continuous and pulsed), and 1.8 J/cm2 and rose bengal concentrations of 0.1%, 0.05%, and 0.01%. Plates were photographed 72 h after experimentation, and analysis was performed to assess fungal growth inhibition. PDAT using 5.4 J/cm2 of irradiation and 0.1% rose bengal completely inhibited growth of five of the seven fungal species. Candida albicans and Fusarium keratoplasticum were the most susceptible organisms, with growth inhibited with the lowest fluence and minimum rose bengal concentration. Fusarium solani, Pseudallescheria boydii, and Paecilomyces variotii were inhibited by lower light exposures and photosensitizer concentrations. Aspergillus fumigatus and Curvularia lunata were not inhibited by any PDAT parameters tested. Continuous and pulsed irradiation using 2.7 J/cm2 produced similar results. Rose bengal PDAT successfully inhibits the in vitro growth of five fungi known to cause infectious keratitis. Differences in growth inhibition of the various fungi to multiple PDAT parameters suggest that susceptibilities to PDAT are unique among fungal species. These findings support modifying PDAT parameters based on the infectious etiology.

Infectious and Noninfectious Corneal Ulcers in Ocular Graft-Versus-Host Disease: Epidemiology, Clinical Characteristics, and Outcomes

PURPOSE

To evaluate the incidence, clinical characteristics, microbiological profile, and therapeutic outcomes of corneal ulcers in individuals with chronic ocular graft-vs-host disease (coGVHD).

DESIGN

Retrospective clinical cohort study.

METHODS

Review of individuals diagnosed with coGVHD following hematopoietic stem cell transplantation (HSCT) who were seen at the Bascom Palmer Eye Institute between May 2010 and November 2021. Baseline demographics, clinical characteristics, microbiological profile, risk factors for corneal ulceration, and treatment outcomes were collected. Etiology was deemed infectious in individuals with a positive culture or appropriate clinical scenario (presence of stromal infiltrate or hypopyon); otherwise, ulcers were presumed to be noninfectious. Treatment success was defined as reepithelialization with infiltrate resolution, and treatment failure as progression to corneal perforation or keratoplasty. Kaplan-Meier survival analysis estimated the incidence of ulceration. Cox regression analyses examined demographic and risk factors. Infectious and noninfectious ulcer groups were compared using 2-way independent t tests, 1-way analysis of variances, and χ2 tests, as appropriate.

RESULTS

173 individuals were included (53.7±14.4 years old; 59.0% male). Thirty-three individuals developed an ulcer 74.5±54.3 months after HSCT, with estimated 5- and 10-year incidences of 14% and 30%, respectively. Twenty-two (66.6%) ulcers were deemed infectious (15 microbiologically confirmed, 7 clinically) and 11 (33.3%) were deemed noninfectious. Risk factors for corneal ulceration included Black race (hazards ratio [HR] 2.89, 95% CI 1.30-6.42, P < .01), previous ocular surgery (HR 9.16, 95% CI 3.86-21.72, P < .01), eyelid margin abnormalities (HR 3.44, 95% CI 1.69-6.99, P < .01), and topical steroid use (HR 2.74, 95% CI 1.33-5.62, P < .01). Conversely, contact lens use reduced the risk of corneal ulceration (HR 0.29, 95% CI 0.13-0.66, P < .01). Infectious ulcers had a significantly higher frequency of treatment failure than noninfectious ulcers (57.1% vs 20.0%, P = .04).

CONCLUSION

Corneal ulceration is a potential complication of coGVHD, with several clinical features identified as risk factors. Infectious ulcers had worse outcomes than noninfectious ulcers.

Translation and validation of the Visual Function and Corneal Health Status (V-FUCHS) questionnaire into Spanish language

PURPOSE

To translate and validate the V-FUCHS questionnaire into Spanish in a population of patients with Fuchs endothelial dystrophy (DEF).

METHODS

The V-FUCHS consists of 15 short, easily understandable questions that assess visual aspects of quality of life in patients with DEF, which can be gathered into a group of seven that assess the "Visual Difficulty" factor and another group of eight that assess the "Glare Factor". For the translation and cultural adaptation, the standardized norms for this process were followed, among other phases, a translation, a back-translation and an application in patients with DEF.

RESULTS

In the first phase, consensus was reached on the Spanish translation of the V-FUCHS. Subsequently, 25 patients were included to carry out the pre-test phase with the aim of assessing the applicability and feasibility of the test. The score obtained a minimum value of -0.88 and a maximum value of +2.44, according to the Rasch probabilistic scale. The mean value obtained from the Visual Difficulty factor was 0.61 (±0.71), while the mean for the Glare Factor was 0.41 (±0.51).

CONCLUSION

The validation of the V-FUCHS questionnaire, after its translation and adaptation into Spanish, proved to be a useful tool for assessing the visual quality of patients with DEF. Patients with a more advanced stage of the disease presented a greater severity in the test result. Likewise, the Glare Factor (Glare) correlates better with the pachymetric increase than with the visual acuity of the patient.

A patient with concurrent Axenfeld-Rieger and Stickler syndromes verified by molecular genetics

Purpose

To report a case of Axenfeld-Rieger and Stickler Syndrome in a pediatric patient.

Observations

A 3-month-old male was referred to the glaucoma clinic after he was noted to have elevated intraocular pressures in both eyes. His family history was notable for infantile glaucoma on his maternal side and retinal detachment on his paternal side. He was found to have anterior segment dysgenesis with iris strands, iridocorneal adhesions, and corectopia, as well as veil-like vitreous in both eyes. He required trabeculotomy, goniotomy, and multiple Baerveldt glaucoma implants in both eyes to achieve intraocular pressure control. Furthermore, the patient later developed macula-involving retinal detachments in both eyes, requiring pars plana vitrectomy with silicone oil tamponade. Genetic analysis confirmed heterozygous pathogenic variants in both the FOXC1 and COL2A1 genes, leading to the concurrent diagnoses of Axenfeld-Rieger and Stickler syndromes.

Conclusions and importance

This is a rare case of a patient with concurrent Axenfeld-Rieger and Stickler syndromes. The severity of pathology in both the anterior and posterior segments required a collaborative multidisciplinary approach. In the diagnostic evaluation of congenital eye diseases, if there is strong family history of atypical findings for a given diagnosis, concurrent syndromes should be considered and ruled out. A comprehensive eye genetics panel may be a useful tool in these cases.

Quantifying Clinicians' Diagnostic Uncertainty When Making Initial Treatment Decisions for Microbial Keratitis

PURPOSE

There is a need to understand physicians' diagnostic uncertainty in the initial management of microbial keratitis (MK). This study aimed to understand corneal specialists' diagnostic uncertainty by establishing risk thresholds for treatment of MK that could be used to inform a decision curve analysis for prediction modeling.

METHODS

A cross-sectional survey of corneal specialists with at least 2 years clinical experience was conducted. Clinicians provided the percentage risk at which they would always or never treat MK types (bacterial, fungal, herpetic, and amoebic) based on initial ulcer sizes and locations (<2 mm 2 central, <2 mm 2 peripheral, and >8 mm 2 central).

RESULTS

Seventy-two of 99 ophthalmologists participated who were 50% female with an average of 14.7 (SD = 10.1) years of experience, 60% in academic practices, and 38% outside the United States. Clinicians reported they would "never" and "always" treat a <2 mm 2 central MK infection if the median risk was 0% and 20% for bacterial (interquartile range, IQR = 0-5 and 5-50), 4.5% and 27.5% for herpetic (IQR = 0-10 and 10-50), 5% and 50% for fungal (IQR = 0-10 and 20-75), and 5% and 50.5% for amoebic (IQR = 0-20 and 32-80), respectively. Mixed-effects models showed lower thresholds to treat larger and central infections ( P < 0.001, respectively), and thresholds to always treat differed between MK types for the United States ( P < 0.001) but not international clinicians.

CONCLUSIONS

Risk thresholds to treat differed by practice locations and MK types, location, and size. Researchers can use these thresholds to understand when a clinician is uncertain and to create decision support tools to guide clinicians' treatment decisions.

Long-Term Comprehensive Management of Bilateral Limbal Stem Cell Deficiency Secondary to Severe Chemical Burn: 10 Years of Follow-Up

PURPOSE

To describe the long-term management of bilateral limbal stem cell deficiency secondary to a severe chemical burn.

METHODS

Descriptive case report.

IMPORTANCE

This case highlights the importance of early intervention in ocular chemical burns for the preservation of tissue integrity and avoidance of perforation. We also review the use of proper ocular surface reconstructive techniques to restore the function of the limbal area, as well as the immunomodulatory strategies and follow-up needed for these interventions.

Twelve-Month Clinical and Histopathological Performance of a Novel Synthetic Cornea Device in Rabbit Model

Purpose

To report the biological stability and postoperative outcomes of a second-generation, single-piece, flexible synthetic cornea in a rabbit model.

Methods

Device materials and design were amended to enhance biointegration. Optic skirt design devices were made from compact perfluoroalkoxy alkane with porous expanded polytetrafluoroethylene ingrowth surface overlying the skirt and optic wall. Sixteen devices were implanted into intrastromal pocket in rabbit eyes. Rabbits were randomly assigned to 6- and 12-month follow-up cohorts (n = 8 in each) postoperatively. Monthly examinations and optical coherence tomography assessed cornea-device integration, iridocorneal angle, optic nerve, and retina.

Results

There were no intraoperative complications. All devices were in situ at exit, with clear optics. No retroprosthetic membrane, glaucoma, cataract formation, or retinal detachment was observed. Two rabbits in the 6-month group had mild, focal anterior lamella thinning without retraction adjacent to the optic near tight sutures. Three postoperative complications occurred in the 12-month group. One rabbit diagnosed with endophthalmitis was euthanized on day 228. Mild sterile focal retraction of anterior lamella occurred in two rabbits, which were terminated on days 225 and 315. Light microscopic examination of enucleated globes demonstrated fibroplasia with new collagen deposition into the porous scaffold without significant inflammation, encapsulation, or granuloma formation.

Conclusions

Clinical evaluations, imaging, and histopathological findings indicate favorable outcomes of this synthetic corneal device in a rabbit model. Early feasibility studies in humans are being planned.

Translational Relevance

Favorable 12-month results of the device in rabbits demonstrate vision-restoring potential in corneally blind individuals at high risk of failure with donor keratoplasty.

Preparing the Ocular Surface for a Boston Keratoprosthesis Type 1 Through En Bloc Minor Salivary Gland Transplantation and Mucous Membrane Grafting in End-Stage Stevens-Johnson Syndrome

PURPOSE

This case describes the successful visual restoration of a patient with end-stage Stevens-Johnson syndrome (SJS) with a severely keratinized ocular surface.

METHODS

This study is a case report.

RESULTS

A 67-year-old man with SJS secondary to allopurinol sought visual rehabilitation options. His ocular surface was severely compromised from sequelae of chronic SJS, leaving him with light perception vision bilaterally. The left eye was completely keratinized with severe ankyloblepharon. The right eye had failed penetrating keratoplasty, limbal stem cell deficiency, and a keratinized ocular surface. The patient declined both a Boston type 2 keratoprosthesis and a modified osteo-odonto keratoprosthesis. Therefore, a staged approach was pursued with (1) systemic methotrexate to control ocular surface inflammation, (2) minor salivary gland transplant to increase ocular surface lubrication, (3) lid margin mucous membrane graft to reduce keratinization, and finally, (4) Boston type 1 keratoprosthesis for visual restoration. After minor salivary gland transplant and mucous membrane graft, the Schirmer score improved from 0 mm to 3 mm with improvement in ocular surface keratinization. This approach successfully restored the vision to 20/60, and the patient has retained the keratoprosthesis for over 2 years.

CONCLUSIONS

Sight restoration options are limited in patients with end-stage SJS with a keratinized ocular surface, aqueous and mucin deficiency, corneal opacification, and limbal stem cell deficiency. This case demonstrates successful ocular surface rehabilitation and vision restoration in such a patient through a multifaceted approach that resulted in successful implantation and retention of a Boston type 1 keratoprosthesis.

Efficacy of Plasma Rich in Growth Factors (PRGF) in Stage 1 Neurotrophic Keratitis

Background/Aims

Neurotrophic keratitis (NK) is a neurodegenerative disease that can lead to corneal hypoesthesia, decreased tear production, and epitheliopathy. Based on the severity of ocular surface damage, NK is classified into 3 stages. Stage 1 NK is characterized by superficial punctate keratopathy, tear film instability, and reduced corneal sensation. The therapeutic efficacy of PRGF eye drops for NK stages 2 and 3 has been previously reported. In this study, we evaluated the efficacy and safety of autologous PRGF eye drops in improving corneal sensitivity and other ocular surface clinical signs in patients with stage 1 NK.

Methods

Retrospective chart review.

Results

26 eyes of 15 stage 1 NK patients (seven males, eight females), aged 76.3 ± 12.1 years, were included in the study. The mean treatment duration was 2 ± 1.8 months. With PRGF treatment, corneal sensitivity increased from 2.8 to 4.5 cm in 53.8% (14/26) (p < 0.01), TBUT increased from 3.6 to 5.0 s in 69.2% (18/26) (p < 0.01), and Schirmer score increased from 13.7 to 16.8 mm in 80.7% (21/26) of treated eyes (p < 0.01). Similarly, an improvement in corneal staining (punctate epithelial erosions) and MMP-9 levels was seen in 80.7% (n = 21) and 65.4% (n = 17) of treated eyes, respectively. BCVA improvement was seen in 26.9% of treated eyes (n = 7).

Conclusions

This study demonstrates the effective role of PRGF therapy in recovering corneal sensation and tear film function and in the healing of corneal erosions in stage 1 NK patients.

Multidrug-Resistant Pseudomonas aeruginosa Keratitis Associated With Artificial Tear Use

This case report describes severe multidrug-resistant Pseudomonas aeruginosa keratitis in a 72-year-old man after EzriCare artificial tear use.

Role of topical and systemic immunosuppression in aqueous-deficient dry eye disease

Immunosuppression in aqueous-deficient dry eye disease (ADDE) is required not only to improve the symptoms and signs but also to prevent further progression of the disease and its sight-threatening sequelae. This immunomodulation can be achieved through topical and/or systemic medications, and the choice of one drug over the other is determined by the underlying systemic disease. These immunosuppressive agents require a minimum of 6-8 weeks to achieve their beneficial effect, and during this time, the patient is usually placed on topical corticosteroids. Antimetabolites such as methotrexate, azathioprine, and mycophenolate mofetil, along with calcineurin inhibitors, are commonly used as first-line medications. The latter have a pivotal role in immunomodulation since T cells contribute significantly to the pathogenesis of ocular surface inflammation in dry eye disease. Alkylating agents are largely limited to controlling acute exacerbations with pulse doses of cyclophosphamide. Biologic agents, such as rituximab, are particularly useful in patients with refractory disease. Each group of drugs has its own side-effect profiles and requires a stringent monitoring schedule that must be followed to prevent systemic morbidity. A customized combination of topical and systemic medications is usually required to achieve adequate control, and this review aims to help the clinician choose the most appropriate modality and monitoring regimen for a given case of ADDE.

Subpalpebral Antibiotic Lavage for the Treatment of Refractory Infectious Scleritis

Infectious scleritis is a potentially devastating condition that can result in severe vision loss. When traditional management fails, a subpalpebral antibiotic lavage system (SAL) can be considered to bathe the infected area with a high volume and concentration of antibiotics. Several reports show that this method can be curative for infectious scleritis, otherwise refractory to care. However, surgical approaches for this technique are either not well described, advocate for transecting the levator aponeurosis, or do not expose the entire width of the superior fornix, which can lead to postoperative ptosis. The authors describe a case where a novel approach was utilized, using a fenestrated angiocather in the superior lateral fornix, to maximize outcomes and minimize postoperative complications. In the setting of infectious scleritis refractory to traditional management, a SAL can be safely and effectively placed with the technique detailed in this report.

Levator Palpebrae Superioris With Inferior Oblique Muscle Flaps for Total Ocular Surface Reconstruction

A healthy middle-aged man sustained extensive burns after a motor vehicle accident, including fourth-degree burns to the ocular adnexa. He had bilateral eyelid necrosis with complete tissue loss to the orbital rim. Progressive corneal thinning occurred bilaterally despite frequent lubrication, weekly amniotic membrane placement, and a Gunderson flap, ultimately requiring evisceration of his OS. In accordance with family wishes to perform all interventions for the OD, he underwent ocular surface reconstruction with levator palpebrae superioris (LPS) and inferior oblique (IO) muscle flaps, supplemented with an orbital fat transfer and bucket-handle muscle flap. These flaps were covered with porcine urinary bladder matrix and remained viable with complete globe coverage postoperatively. Although local eyelid flaps traditionally involve tissue supplied by branches of the external carotid artery, this case suggests that orbital-internal carotid artery based flaps utilizing the LPS and IO muscles may achieve ocular surface coverage after complete periocular and facial soft tissue loss.

Considerations for Corneal Surgery With Patients in the 10th Decade of Life

PURPOSE

The purpose of this study was to report the indications, ocular and systemic comorbidities, and surgical outcomes of corneal transplantation in patients older than 90 years.

METHODS

A retrospective review was conducted to identify individuals 90 years and older who underwent corneal transplantation surgery at the Bascom Palmer Eye Institute between January 2013 and October 2020. Outcomes included best-corrected visual acuity and graft survival over time. Paired t tests were used to compare visual acuity preoperatively versus postoperatively. Graft survival was evaluated with Kaplan-Meier curves.

RESULTS

Fifty-eight eyes of 52 consecutive individuals were included. The mean age of individuals was 92 ± 2 years; 26.9% were male; and 48.1% self-identified as non-Hispanic White and 38.5% as Hispanic. Postoperative follow-up was 14.7 ± 12.1 months. Of the 58 eyes, 44.8% (26/58) underwent penetrating keratoplasty, 46.6% (27/58) Descemet stripping automated endothelial keratoplasty, and 6.9% (4/58) keratoprosthesis. All surgeries were performed under monitored local anesthesia, without major complications. Surgical indications included pseudophakic bullous keratopathy (36.2%), glaucoma-associated corneal decompensation (27.6%), Fuchs endothelial dystrophy (25.9%), and perforated corneal ulceration (19.0%). The best-corrected visual acuity improved by 0.32 (95% confidence interval 0.14-0.50; P < 0.01) as early as 1 month postoperatively, and vision gains were sustained for at least 12 months. Graft survival probability at 12 months was 88%.

CONCLUSIONS

Corneal transplantation is a safe and successful procedure in restoring the visual acuity for patients older than 90 years after careful preoperative evaluation. Further research is needed to evaluate the impact of corneal transplantation on quality of life in patients in the 10th decade of life.

Impact of Cataract Surgery on Low Luminance Visual Acuity Deficit Measurements

Purpose

The impact of cataract surgery on low luminance visual acuity deficit (LLVAD) measurements was investigated by measuring the LLVAD before and after cataract surgery.

Design

Prospective, longitudinal study.

Participants

Patients undergoing cataract surgery.

Methods

Photopic luminance (PL)–best-corrected visual acuity (BCVA) and low luminance (LL)–BCVA were obtained using the ETDRS chart. Low luminance visual acuity deficit scores were calculated by subtracting the LL-BCVA letter score from the PL-BCVA letter score. To demonstrate the reproducibility of these visual acuity measurements, we used data from drusen-only eyes previously published in the Complement Inhibition with Eculizumab for the Treatment of Nonexudative Age-Related Macular Degeneration (COMPLETE) study. The PL-BCVA, LL-BCVA, and LLVAD measurements obtained at an interval of 3 months in this cohort were used for comparison. In the current study, the impact of cataract surgery on LLVAD measurements was analyzed by comparing the PL-BCVA, LL-BCVA, and LLVAD measurements before and after cataract surgery.

Main Outcome Measures

The reproducibility of the visual acuity measurements and the changes in LLVAD measurement after cataract surgery.

Results

In the COMPLETE study, no clinically significant differences were found in the PL-BCVA, LL-BCVA, or LLVAD measurements between baseline and the 3-month follow-up visits with a change of –1.1 letters, –1.3 letters, and 0.1 letters, respectively (P = 0.02, P = 0.11, and P = 0.88, respectively). In the current study, significant increases were found in the PL-BCVA and LL-BCVA measurements, with a change of 7.3 letters and 10.2 letters after cataract surgery (P < 0.001 for both), and a statistically significant decrease in LLVAD measurements was found, with a change of –3.0 letters after cataract surgery (P = 0.002).

Conclusions

Because of the variable effect of cataracts on LL-BCVA measurements and the significant change in LLVAD measurements after cataract surgery, investigators should be aware that cataract surgery during a trial will have an unpredictable impact on LLVAD measurements, and pseudophakic and phakic patients should be analyzed separately.

Rose Bengal Photodynamic Antimicrobial Therapy: A review of the intermediate term clinical and surgical outcomes

PURPOSE

To evaluate the intermediate term clinical outcomes of Rose Bengal Photodynamic Antimicrobial Therapy (RB-PDAT) for infectious keratitis. Secondarily, to evaluate the surgical outcomes of individuals that underwent optical keratoplasty after RB-PDAT.

DESIGN

Retrospective cohort study.

METHODS

Retrospective chart review of 31 eyes from 30 consecutive individuals with infectious keratitis refractory to standard medical therapy who underwent RB-PDAT at the Bascom Palmer Eye Institute between January 2016 and July 2020. Data collected included demographics, risk factors for infectious keratitis, microbiological diagnosis, Best Spectacle-Corrected Visual Acuity (BCVA), clinical outcomes after RB-PDAT and complication rates post-keratoplasty. RB-PDAT was performed as described in previous studies. Graft survival was evaluated using Kaplan Meier curves with log-ranks in individuals that underwent keratoplasty after RB-PDAT.

RESULTS

Mean age of the study population was 53±18.0 years. 70% were female; 53.3% self-identified as non-Hispanic White; 43.3% as Hispanic. Mean follow-up time was 28.0±14.4 months. Risk factors included contact lens use (80.6%), history of infectious keratitis (19.3%), and ocular surface disease (16.1%). Cultures were positive for Acanthamoeba (51.6%), Fusarium (12.9%), and Pseudomonas (6.5%). 22.5% of individuals with Acanthamoeba infection were treated with concomitant Miltefosine. Clinical resolution was achieved in 77.4% of individuals on average 2.72±1.85 months after RB-PDAT with 22.5% requiring therapeutic penetrating keratoplasties and 54.8% subsequently requiring optical penetrating keratoplasties. At 2 years, the overall probability of graft survival was 78.7% and the graft failure rate was 21.3%.

CONCLUSION

RB-PDAT is a potential adjunct therapy for infectious keratitis that may reduce the need for a therapeutic penetrating keratoplasty. Cases that undergo keratoplasty after RB-PDAT may have a higher probability of graft survival at one year postoperatively.

Role of corneal biopsy in the management of infectious keratitis

PURPOSE OF REVIEW

The aim of this study was to review the existing literature and investigate the role of microbiologic culture and histopathologic examination of corneal biopsies in the management of infectious keratitis.

RECENT FINDINGS

Corneal biopsy continues to be a significantly useful tool in the diagnosis and tailored management of infectious keratitis. Several techniques can be employed for tissue collection, handling and processing to optimize diagnostic yield and maximize safety, including emerging femtosecond laser-assisted biopsy.

SUMMARY

Corneal opacities represent a significant cause of global blindness, and infectious keratitis is the most common cause. Organism identification in progressive infectious keratitis is essential for proper management. However, microbiological culture alone has a high rate of false-negative results. Records from the Bascom Palmer Eye Institute were retrospectively searched for patients between 1 January 2015, and 31 December 2019, who underwent corneal biopsy, therapeutic keratoplasty or endothelial graft removal for infectious keratitis and had specimens bisected and submitted for evaluation with both microbiologic culture and histopathologic examination. Detection of bacteria, fungus and mycobacteria was not statistically different between culture and histopathology. Microbiology and histopathology are complementary methods for the identification of causative microorganisms in corneal specimens with presumed infectious keratitis.

Nocardia keratitis: amikacin nonsusceptibility, risk factors, and treatment outcomes

PURPOSE

To report the increasing trends in Nocardia keratitis species diversity and in vitro antibiotic susceptibility, to demonstrate contact lens wear as a risk factor, and to report visual acuity outcomes after treatment.

METHODS

A retrospective clinical case series was performed at a single academic referral center which identified 26 patients with culture-confirmed Nocardia keratitis between 2014 and 2021. A combination of conventional microbiology and molecular techniques were used to identify isolates. Antibiotic susceptibilities were determined using both commercial and in-house laboratory methods. Microbiology and electronic medical records were used to characterize patients' clinical profiles.

RESULTS

Patients' median age was 32.5 years with a 2:1 male to female ratio. Eighty-four percent (n = 21/25) of patients were diagnosed within two weeks of symptom onset. Nocardia amikacinitolerans (n = 11/26) was the most recovered Nocardia isolate among study patients. Sixty-four percent (n = 16/25) of all isolates, including all 11 N. amikacinitolerans isolates, were resistant to amikacin. All isolates were susceptible to trimethoprim sulfamethoxazole. Contact lens wear was the leading identified risk factor (n = 23/26) in this population. Median time to resolution was 44 days (n = 23, range: 3-190 days). Seventy-one percent of patients (n = 15/21) had a final visual acuity of 20/40 or better.

CONCLUSION

Amikacin resistant Nocardia isolates were the majority in the current study. Trimethoprim sulfamethoxazole may be the preferred alternative antibiotic treatment based on in vitro susceptibilities. Contact lens wear was the major risk factor for Nocardia keratitis in South Florida. Overall visual acuity treatment outcomes of patients were favorable.

Risk and Impact of Severe Acute Respiratory Syndrome Coronavirus 2 Infection on Corneal Transplantation: A Case-Control Study

PURPOSE

The purpose of this study was to evaluate the risk of symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection after corneal transplantation surgery, with cataract surgeries as controls, and the impact of the novel coronavirus disease pandemic in the clinical and surgical complications of corneal transplantation and cataract surgeries.

METHODS

A retrospective matched case-control study of 480 consecutive individuals who underwent surgery at the Bascom Palmer Eye Institute between May 2020 and November 2020. A total of 240 patients who underwent corneal transplantation with tissue obtained from the Florida Lions Eye Bank were age, race, ethnicity, and sex matched with 240 patients who underwent cataract surgery during the same day and by the same surgical team. Only the first corneal transplant or cataract surgery during this period was considered for each individual. All donors and recipients were deemed SARS-CoV-2 negative by a nasopharyngeal polymerase chain reaction test before surgery. Postoperative SARS-CoV-2 infections were defined as previously SARS-CoV-2(-) individuals who developed symptoms or had a positive SARS-CoV-2 polymerase chain reaction test during the first postoperative month.

RESULTS

Mean age, sex, race, and ethnicity were similar between groups. There were no differences between the corneal transplant and cataract groups in the rates of SARS-CoV-2 infection before (5.8% vs. 7.5%, P= 0.6) or after surgery (2.9% vs. 2.9%, P = 1). The rates of postoperative complications did not increase during the pandemic, compared with previously reported ranges.

CONCLUSIONS

In this study, postoperative SARS-CoV-2 infection was similar for individuals undergoing corneal transplantation or cataract surgery. Further research is required to evaluate the transmission of SARS-CoV-2 through corneal tissue.

Rose Bengal and Riboflavin Mediated Photodynamic Antimicrobial Therapy Against Selected South Florida Nocardia Keratitis Isolates

Purpose

To examine and compare the efficacy of in vitro growth inhibition using rose bengal and riboflavin photodynamic antimicrobial therapy (PDAT) for Nocardia keratitis isolates.

Methods

Nocardia asteroides complex, Nocardia amikacinitolerans, and Nocardia farcinica species were isolated from patients with confirmed Nocardia keratitis. Isolates were tested against three experimental groups: (1) no photosensitizer/no irradiation, (2) photosensitizer/no irradiation, and (3) photosensitizer/irradiation. Each isolate was prepared in suspension to a concentration of 1.5 × 10⁸ CFU/mL. Bacterial suspensions were mixed with water or prepared 0.1% photosensitizer solution for a final bacterial concentration of 1.5 × 10⁷ CFU/mL. Aliquots of 1 mL were plated on 5% sheep blood agar. Rose bengal and riboflavin PDAT plates were irradiated for 15 minutes with a 525- or 375-nm custom 6-mW/cm² powered light source for a total fluence of 5.4 J/cm². All experimental groups were repeated in triplicate. Plates were incubated in a 35°C non-CO₂ incubator for 96 hours and photographed. Percent inhibition was evaluated using LabVIEW-based software.

Results

All strains of Nocardia tested with 0.1% rose bengal and irradiated for 15 minutes demonstrated statistically significant inhibition of growth (P < 0.05). No other experimental groups displayed any bacterial inhibition.

Conclusions

Rose bengal is superior to riboflavin PDAT against selected Nocardia isolates. In vivo testing is warranted to investigate the utility of rose bengal PDAT for severe Nocardia keratitis.

Translational Relevance

In vitro results for three clinical strains of Nocardia support the possible use of rose bengal PDAT as a complementary treatment of Nocardia keratitis.

Double-masked, sham and placebo-controlled trial of corneal cross-linking and topical difluprednate in the treatment of bacterial keratitis: Steroids and Cross-linking for Ulcer Treatment Trial (SCUT II) study protocol

Introduction

Although antibiotics are successful at achieving microbiological cure in infectious keratitis, outcomes are often poor due to corneal scarring. Ideal treatment of corneal ulcers would address both the infection and the inflammation. Adjunctive topical steroid treatment may improve outcomes by reducing inflammation. Corneal cross-linking (CXL) is a novel prospective therapy that may simultaneously reduce both inflammatory cells and bacterial pathogens. The purpose of this study is to determine differences in 6-month visual acuity between standard medical therapy with antibiotics versus antibiotics with adjunctive early topical steroid therapy versus antibiotic treatment plus CXL and early topical steroids.

Methods and analysis

This international, randomised, sham and placebo-controlled, three-arm clinical trial randomises patients with smear positive bacterial ulcers in a 1:1:1 fashion to one of three treatment arms: (1) topical 0.5% moxifloxacin plus topical placebo plus sham CXL; (2) topical 0.5% moxifloxacin plus difluprednate 0.05% plus sham CXL; or (3) the CXL group: topical 0.5% moxifloxacin plus difluprednate 0.05% plus CXL.

Ethics and dissemination

We anticipate that both adjunctive topical steroids and CXL will improved best spectacle corrected visual acuity and also reduce complications such as corneal perforation and the need for therapeutic penetrating keratoplasty. This study will comply with the NIH Data Sharing Policy and Policy on the Dissemination of NIH-Funded Clinical Trial Information and the Clinical Trials Registration and Results Information Submission rule. Our results will be disseminated via ClinicalTrials.gov website, meetings and journal publications. Our data will also be available on reasonable request.

Trial registration number

NCT04097730.

Photodynamic Therapy for Infectious Keratitis

Infectious keratitis is a sight-threatening microbial infection. The prevalence of antimicrobial resistance in cases of infectious keratitis has increased the demand for fortified compounded antimicrobial drops. Even with proper medical management, severe cases of infectious keratitis can further evolve into corneal perforation, requiring surgical intervention in the form of keratoplasty to control the infectious process. Due to the invasive nature of the procedure and the shortage of available donor tissue around the world, alternative treatments are needed for the management of progressive infectious keratitis. In ophthalmology, photodynamic therapy (PDT) has been used for numerous applications. PDT with Rose Bengal as a photosensitizer combined with green light optical irradiation (RB-PDAT) is a novel treatment with dual purpose: to arrest the infection from progressing and strengthen the collagen of the cornea. RB-PDAT may be considered as an adjunct therapy in severe cases of infectious keratitis to minimize the need for a therapeutic keratoplasty.

Rose Bengal Photodynamic Antimicrobial Therapy: A Pilot Safety Study

PURPOSE

To evaluate the in vivo corneal changes after Rose Bengal photodynamic antimicrobial therapy (RB-PDAT) treatment in New Zealand White rabbits.

METHODS

Sixteen rabbits were divided into 5 groups. All groups underwent deepithelialization of an 8 mm diameter area in the central cornea. Group 1: balanced salt solution drops only, group 2: 0.2% RB only, group 3: green light exposure (525 nm, 5.4 J/cm2) only, group 4: 0.1% RB-PDAT, and group 5: 0.1% RB-PDAT. All rabbits were followed clinically. Group 5 rabbits were followed using anterior segment optical coherence tomography (AS-OCT) and clinically. On day 35 after initial treatment, 1 rabbit from group 5 was re-exposed to green light (5.4 J/cm2) to evaluate reactivation of the remaining RB dye, and terminal deoxynucleotyl transferase-mediated UTP-biotin-nick-end labeling assay was performed on corneal cryosections.

RESULTS

Complete reepithelization was observed, and corneas remained clear after treatment in all groups. In group 5, AS-OCT revealed a cross-linking demarcation line. AS-OCT showed RB fluorescence and collagen cross-linking in all treated eyes of group 5 animals after 5 weeks of treatment. Photobleached RB retention in the corneal stroma was corroborated by fluorescence confocal microscopy on frozen sections. There was no evidence of a sustained cytotoxic effect through terminal deoxynucleotyl transferase-mediated UTP-biotin-nick-end labeling at 5 weeks.

CONCLUSIONS

RB-PDAT with 0.1% RB is a safe procedure. There was no difference clinically and on histopathology compared with control groups. In eyes where RB dye is retained in the corneal stroma after 1 month of treatment, oxidative stress is not evidenced at long term.

Tumor necrosis factor-alpha and interferon-gamma induce inflammasome-mediated corneal endothelial cell death

PURPOSE

Chronic corneal endothelial cell (CEC) loss results in corneal edema and vision loss in conditions such as pseudophakic bullous keratopathy (PBK), Fuchs' dystrophy, and corneal graft failure. Low CEC density has been associated with an elevation of intraocular pro-inflammatory cytokines such as tumor necrosis factor (TNF)-α and interferon (INF)-γ. These cytokines are capable of triggering pyroptosis, a programmed cell death mechanism mediated by the inflammasome, prompting the activation of the pro-inflammatory cytokine interleukin (IL)-1β, the perpetuation of inflammation, and subsequent damage of corneal endothelial tissue. Therefore, the purpose of this study was to determine the deleterious contribution of the inflammasome and pyroptosis to CEC loss.

METHODS

CECs from human donor corneas were treated ex vivo with TNF-α and IFN-γ for 48 h. Levels of caspase-1 and IL-1β were then assayed by ELISA, and the expression of caspase-1 and gasdermin-D (GSDM-D) were confirmed by immunofluorescence. Endothelial cell damage was analyzed by a lactate dehydrogenase (LDH) release assay, and oxidative stress was determined by measuring the levels of reactive oxygen species (ROS) in the culture media.

RESULTS

Inflammasome activation and oxidative stress were elevated in CECs following exposure to TNF-α and IFN-γ, which resulted in cell death by pyroptosis as determined by LDH release which was inhibited by the caspase-1 inhibitor Ac-YVAD-cmk.

CONCLUSION

CEC death is induced by the pro-inflammatory cytokines TNF-α and IFN-γ, which contribute to inflammasome activation. Moreover, the inflammasome is a promising therapeutic target for the treatment of chronic CEC loss.

UV-Photokeratitis Associated with Germicidal Lamps Purchased during the COVID-19 Pandemic

PURPOSE

To report photokeratitis caused by the improper use of germicidal lamps purchased during the COVID-19 pandemic.

METHODS

Case series.

RESULTS

Seven patients presented with acute ocular surface pain after exposure to UV-emitting germicidal lamps. Visual acuity was 20/30 or better in 13 of 14 eyes (93%). Anterior segment examination revealed varying degrees of conjunctival injection and diffusely distributed punctate epithelial erosions (PEEs) in every patient. No intraocular inflammation was identified across the cohort and all fundus examinations were normal. Treatment varied by provider and included artificial tears alone or in combination with antibiotic ointments and/or topical steroids. Five patients were followed via telehealth, one patient returned for an in-office visit, and one patient was lost to follow-up. Five of six patients endorsed complete resolution of symptoms within 2-3 days.

CONCLUSIONS

Patients should follow manufacturer recommendations when using UV-emitting germicidal lamps and avoid direct exposure to the ocular surface.

Minor salivary gland transplantation for severe dry eye disease due to cicatrising conjunctivitis: multicentre long-term outcomes of a modified technique

AIM

To report the clinical outcomes of autologous minor salivary gland transplantation (MSGT) for the treatment of severe dry eye disease caused by cicatrising conjunctivitis.

METHODS

This was a retrospective case series of patients undergoing MSGT at four different centres from 2016 to 2018. The technical modifications included en bloc harvesting of a 20 mm×15 mm mucosa-gland-muscle complex and fixation of the glands to the superior bulbar surface anchored to the superior rectus muscle. The primary outcome measure was improvement in best-corrected visual acuity (BCVA). Secondary outcome measures were change in Schirmer test scores and grades of conjunctival and corneal fluorescein staining, grades of corneal neovascularisation, opacification and keratinisation.

RESULTS

21 eyes of 19 patients underwent MSGT, with a median follow-up duration of 3 years. The median BCVA improved from a baseline value of 20/500 to 20/125 at 1 year (p=0.0004) and 20/80 at 3 years (p=0.0002) after surgery. The proportion of cases with BCVA ≥20/200 improved from 38% at baseline to 67% at 1 year (p=0.0294), 78% at 2 years (p=0.0227) and 93% at 3 years (p=0.0015) after surgery. There was a significant improvement (p<0.0036) in Schirmer scores, conjunctival and corneal staining scores as well as grades of corneal neovascularisation and opacification after surgery. There were no serious sight-threatening complications in the transplanted eyes or at the donor site.

CONCLUSIONS

Long-term improvement in the visual acuity, ocular surface environment, and keratopathy was noted after MSGT performed in severely dry eyes using a modified technique.

Chronic, Recurrent Bacterial Endophthalmitis Caused by Achromobacter xylosoxidans: Clinical Features and Management

A 79-year-old man presented to a tertiary referral center from the Dominican Republic with an opaque corneal graft and a diagnosis of chronic, recurrent culture-positive Achromobacter xylosoxidans endophthalmitis of the left eye. The patient had a history of penetrating keratoplasty for Fuchs' dystrophy and had undergone multiple intraocular surgeries including pars plana vitrectomy and anterior chamber wash out for the diagnosis and management of chronic endophthalmitis. After being referred, the patient underwent a third PKP, removal of his intraocular lens (IOL), capsulectomy, and injection of intravitreal antibiotics. All surgical specimens demonstrated the growth of A. xylosoxidans. Five months after surgery, the graft remained clear without evidence of infection and best-corrected visual acuity was 20/350.