Outcomes of Descemet Stripping Only Without Postoperative Use of Topical Rho-associated Protein Kinase Inhibitors.

PURPOSE: Descemet Stripping Only (DSO) is a promising surgical option for select patients with Fuchs endothelial dystrophy (FED). There is growing support for the use of topical Rho-associated protein kinase inhibitors (ROCKi) to optimize DSO outcomes. However, in many settings, ROCKi are either unavailable or not approved to treat corneal diseases. This study sought to characterize patient outcomes after DSO in the absence of ROCKi and potentially broaden the settings where DSO can be offered to patients. METHODS: Single-center retrospective case series of 15 eyes/11 patients (66 years; 52-74) that underwent DSO, alone or combined with cataract surgery, by one surgeon between August 2020 and January 2023. Patients included in analyses had FED with central guttae, no clinical evidence of corneal edema, and a clinically healthy peripheral corneal endothelium. RESULTS: Mean follow-up time was 14 months (2-34). Fourteen of 15 eyes achieved corneal clearance (93.3%). Mean time to clearance was 8.5 weeks (3-23). Eleven eyes (73%) achieved corrected distance visual acuity of ≤0.2 with a significant postoperative improvement at 4 to 8 months (P < 0.05) and sustained improvements at >12 months. No significant astigmatism was introduced by the procedure. Two eyes developed cystoid macular edema postoperatively. A trend toward earlier clearance was observed in the <65 years old group. CONCLUSIONS: Despite a longer time to corneal clearance in this cohort compared with the few studies using ROCKi, the overall success rate and visual outcomes for the patients in our cohort supports the use of DSO in settings where ROCKi are not readily available.

The Impact of Vaping on the Ocular Surface: A Systematic Review of the Literature.

Background: The use of electronic cigarettes has become increasingly popular in recent years. However, the impact that electronic cigarettes have on the ocular surface is not well known. Therefore, the aim of this review is to explore the current literature on the acute and chronic sequelae of electronic cigarettes on the ocular surface. Methods: A systematic review of the literature was undertaken by keyword searching on the Embase, Medline, and Web of Science databases. Articles identified through the search underwent title/abstract screening, full-text screening, and data extraction. Results: A total of 18 studies were included in this review. Non-intended ocular surface exposures and intended exposures on the ocular surface were found to be associated with the use of electronic cigarettes. Conclusions: The impact of vaping on the ocular surface is not benign. There are significant risks that vaping can pose to the ocular surface. Hence, it is necessary to develop appropriate risk communication tools given the increasing popularity of this activity. Additionally, future long-term studies are needed to better understand the long-term impacts of vaping on the ocular surface given the lack of current data.

Trends and Clinical Outcomes of Fungal Keratitis in Canada: A 20-year Retrospective Multicentre Study.

PURPOSE: An increase in fungal and particularly filamentous keratitis has been observed in many geographic areas, mostly in contact lens wearers. This study seeks to characterize long-term trends in fungal keratitis in a continental climate area to provide guidance for diagnosis and treatment. DESIGN: Retrospective multicentric case series. METHODS: Cases of microbiology-confirmed fungal keratitis from 2003 to 2022 presenting to tertiary care centers across Canada were included. Charts were reviewed for patient demographics, risk factors, visual acuity, and treatments undertaken. RESULTS: A total of 138 patients were identified: 75 had yeast keratitis while 63 had filamentous keratitis. Patients with yeast keratitis had more ocular surface disease (79% vs 28%) while patients with filamentous keratitis wore more refractive contact lenses (78% vs 19%). Candida species accounted for 96% of all yeast identified, while Aspergillus (32%) and Fusarium (26%) were the most common filamentous fungi species. The mean duration of treatment was 81 ± 96 days. Patients with yeast keratitis did not have significantly improved visual acuity with medical treatment (1.8 ± 1 LogMAR to 1.9 ± 1.5 LogMAR, P = .9980), in contrast to patients with filamentous keratitis (1.4 ± 1.2 LogMAR to 1.1 ± 1.3 LogMAR, P = .0093). CONCLUSIONS: Fungal keratitis is increasing in incidence, with contact lenses emerging as one of the leading risk factors. Significant differences in the risk factors and visual outcomes exist between yeast keratitis and filamentous keratitis which may guide diagnosis and treatment.

Predicting Long-Term Endothelial Cell Loss after Preloaded Descemet Membrane Endothelial Keratoplasty in Fuchs' Endothelial Corneal Dystrophy: A Mathematical Model.

(1) Background: This study offers a biexponential model to estimate corneal endothelial cell decay (ECD) following preloaded "endothelium-in" Descemet membrane endothelial keratoplasty (DMEK) in Fuchs' endothelial corneal dystrophy (FECD) patients; (2) Methods: A total of 65 eyes undergoing DMEK alone or combined with cataract surgery were evaluated. The follow-up period was divided into an early phase (first 6 months) and a late phase (up to 36 months). Endothelial cell count (ECC) and endothelial cell loss (ECL) were analyzed; (3) Results: The half time of the ECD was 3.03 months for the early phase and 131.50 months for the late phase. The predicted time-lapse interval to reach 500 cells/mm2 was 218 months (18.17 years), while the time-lapse interval to reach 250 cells/mm2 was 349 months (29.08 years). There was no statistically significant difference between the ECL in DMEK combined with cataract extraction and DMEK alone at 24 months (p ≥ 0.20). At the late phase, long-term ECL prediction revealed a lower ECC half time in patients undergoing DMEK combined with cataract surgery (98.05 months) than DMEK alone (250.32 months); (4) Conclusions: Based on the mathematical modeling, a predicted average half-life of a DMEK graft could reach 18 years in FECD. Moreover, combining cataract extraction with DMEK could result in excessive ECL in the long term.

Global impact of COVID-19 on corneal donor tissue harvesting and corneal transplantation.

Introduction: The purpose of this review is to consolidate and examine the available literature on the coronavirus disease 2019 pandemic and its effect on corneal transplantation and eye banking. Methods: A primary literature search was conducted using the PubMed (Medline) database with keywords and MeSH terms such as "corneal transplantation," "eye banks," "keratoplasty" and then were combined with COVID-19. Relevant articles through September 2022 were assessed and 25 articles were included in this review. Results: Donor tissue volumes declined globally during lockdown periods due to a lower number of referrals and tighter tissue screening guidelines. Rates of elective surgeries decreased in the lockdown period compared to respective periods in previous years. However, changes in rates of emergency procedures were not uniform across different regions. Moreover, rates of different elective corneal grafts [i.e., penetrating keratoplasty (PK), endothelial keratoplasty (EK), or anterior lamellar keratoplasty (ALK)] were affected differently with the pattern of change being dependent on region-specific factors. Conclusion: Both donor tissue volumes and rates of corneal transplant procedures were affected by lockdown restrictions. The underlying etiology of these changes differed by region. Examining the range of impact across many countries as well as the contributing factors involved will provide guidance for future global pandemics.

Outcomes of XEN Stent in Patients With Glaucoma and Previous Corneal Transplantation.

PRCIS: The XEN stent safely and effectively controls intraocular pressure in select patients with history of corneal transplantation. PURPOSE: Glaucoma is a common complication after corneal transplantation and can be difficult to manage in these patients. This study reports outcomes of XEN stent implantation in eyes with glaucoma in the setting of previous corneal transplantation. PATIENTS AND METHODS: Noncomparative retrospective case series including eyes with a history of corneal transplantation and subsequent XEN stent implantation by a single glaucoma surgeon in Surrey, British Columbia, between 2017 and 2022. The analysis included patient demographics, pre and postoperative intraocular pressure (IOP), pre and postoperative glaucoma medications, peri and postoperative complications and interventions, and incidence of repeat corneal transplantation and additional glaucoma procedures to control IOP. RESULTS: Fourteen eyes with previous cornea transplantation underwent XEN stent implantation. Mean age was 70.1 years (range: 47-85 y). Mean follow-up was 18.2 months (range: 1.5-52 mo). The most common glaucoma diagnosis was secondary open angle glaucoma (50.0%). There was a significant reduction in IOP and the number of glaucoma agents at all postoperative time points ( P < 0.05). IOP decreased from 32.7 ± 10.0 mm Hg at baseline to 12.5 ± 4.7 mm Hg at the most recent follow-up. Glaucoma agents decreased from 4.0 ± 0.7 to 0.4 ± 1.0. Two eyes required additional glaucoma surgery to control IOP, with an average time to reoperation of 7 weeks. Two eyes underwent repeat corneal transplantation, with an average time to reoperation of 23.5 months. CONCLUSIONS: In selected patients with previous corneal transplants and refractory glaucoma, the XEN stent was safely implanted and effectively reduced IOP in the short term.

Visual Outcomes of Cataract Surgery in Patients With Keratoconus Using Toric and Non-toric Lenses.

PURPOSE: To compare the accuracy and outcomes of different intraocular lens (IOL) power calculation formulas in eyes with keratoconus undergoing cataract surgery with toric and non-toric IOLs. METHODS: This was a consecutive retrospective case series study including patients from the Cornea Service at the Department of Ophthalmology and Visual Sciences at the University of British Columbia, Vancouver, Canada, from 2000 to 2020. Keratoconus was diagnosed based on corneal topography and clinician opinion. Patients who underwent topography-guided photorefractive keratectomy, intracorneal ring segments implantation, or corneal transplant were excluded. The manifest spherical equivalent, prediction errors, and median absolute errors were calculated. Descriptive statistics were expressed as mean ± standard deviation. RESULTS: There were 160 eyes from 101 patients; 136 eyes received non-toric lenses and 24 eyes received toric lenses. Most patients had mild disease (< 48.00 diopters [D]) when stratified by steep keratometry values. Patients with severe disease (> 53.00 D) were significantly more hyperopic following surgery (P < .05). The Barrett Universal II (0.26 D, inter-quartile range [IQR] = 0.4), Holladay 2 (0.31, IQR = 1.2), and SRK/T (0.42, IQR = 0.86) formulas had the lowest median absolute error. The postoperative prediction error following toric lens insertion was not significantly different than following non-toric lens insertion, and the mean absolute astigmatism was significantly reduced with toric lenses. CONCLUSIONS: The Barrett Universal II, Holladay 2, and SRK/T were the most accurate IOL power calculation formulas in patients with keratoconus undergoing cataract surgery. Hyperopic surprise was increased in severe keratoconus. Toric IOLs may be considered in patients with mild keratoconus. [J Refract Surg. 2023;39(5):319-325.].

Superior limbic keratoconjunctivitis: Update on pathophysiology and management.

Superior limbic keratoconjunctivitis (SLK) is an under-recognized condition characterized by a final common pathologic presentation of superior conjunctival and limbal inflammation and staining. Existing literature attributes both microtrauma and local inflammation, frequently in the setting of tear film insufficiency, as the underlying mechanisms that lead to a self-perpetuating pathologic process dependent in on inflammatory cells and signaling. Effective treatments act by targeting inflammation and by mitigating mechanical stressors. This critical review discusses the latest in our understanding of the pathophysiology of SLK and how it guides our treatment strategies.

Long-term outcomes of fornix reconstruction and cicatricial entropion repair in ocular mucous membrane pemphigoid and drug-related secondary pemphigoid.

OBJECTIVE: To investigate the long-term outcomes of fornix reconstruction and cicatricial entropion repair in patients with ocular mucous membrane pemphigoid (MMP) and secondary MMP. METHODS: Retrospective chart review of patients with MMP undergoing either fornix reconstruction (with amniotic membrane or buccal mucosal graft) or Wies cicatricial entropion repair between January 1, 2000, and September 1, 2020. Patients had a positive mucosal biopsy and (or) clinical features of MMP or secondary MMP. The primary outcome was overall success of fornix reconstruction based on fornix depth maintenance at latest follow-up. Secondary outcomes included resolution of trichiasis, visual acuity, and improvement of subjective symptoms. RESULTS: Eight patients (10 eyes) with a diagnosis of MMP (3 males and 5 females; median age, 71 years) and 4 patients (4 eyes) with a diagnosis of secondary MMP (2 females and 2 male; median age, 87 years) were enrolled. Mean follow-up was 22.7 months (range, 0.3-87.5 months) for MMP patients and 15.4 months (range, 3.0-43.9 months) for secondary MMP patients. For MMP eyes, 30.0% underwent fornix reconstruction, 60.0% underwent entropion repair, and 10.0% received both. Re-formation of symblepharon and loss of fornix depth occurred in all MMP eyes at an average of 6.4 ± 7.0 months postoperatively, and trichiasis recurred in all patients at the last follow-up visit. In secondary MMP patients, 75.0% of the eyes showed recurrence of symblepharon, and 66.7% re-formed trichiasis. Both MMP and secondary MMP patients had short-term symptom improvements. CONCLUSIONS: Fornix reconstruction and cicatricial entropion repair in our cohort of MMP and secondary MMP patients resulted in short-term symptomatic improvement, but recurrence was seen, on average, at 6 months postoperatively.

Pathophysiology of Corneal Endothelial Cell Loss in Dry Eye Disease and Other Inflammatory Ocular Disorders.

PURPOSE: Dry eye disease (DED) and other inflammatory ocular disorders have been reported to be associated with decreased corneal endothelial cell density (CECD), however the mechanism of underlying endothelial cell loss remains unknown. METHODS: We conducted a comprehensive literature search of English-written publications on dry eye disease, corneal endothelial cell loss, Sjögren's syndrome, and Graft Vs Host Disease (GVHD), to review the effects of DED and other inflammatory ocular surface conditions on CECD. RESULTS: A total of 78 studies were included in our study. Loss of corneal neurotrophic support, cytotoxic stress, and a heightened immune response, all of which may occur secondarily to a common causative agent such as inflammation, are major contributors to reduced CECD. CONCLUSION: More studies are needed to determine how the interrelated pathways of altered corneal nerve function and upregulated expression of inflammatory activity influence corneal endothelial cell loss.

Impact of the use of anti-glaucoma medications on the risk of herpetic keratitis recurrence.

PURPOSE: Numerous case reports have associated anti-glaucoma medications with recurrence of herpes simplex virus (HSV) and herpes zoster virus (HZV) keratitis. The aim of our study was to determine whether different anti-glaucoma agents are associated with recurrence of herpetic keratitis. METHODS: This was a retrospective cohort study using health databases from a Canadian province from January 2001 to December 2012. A new cohort of users on topical prostaglandins (PGs), beta blockers (BBs), alpha-2 agonists (AAs) and carbonic anhydrase inhibitors (CAIs) was created. The date of the third anti-glaucoma drug dispensation within 90 days was deemed the index date of the case. Herpetic keratitis events, as defined by an ICD-9/10 code for HSV or HZV keratitis, or the dispensation of an anti-viral medication by either an ophthalmologist or an optometrist, were examined prior to and following the index date. Risk ratios (RRs) were computed to compare the risk of HSV/HZV keratitis among the PG, BB, AA, and CAI groups individually and collectively while adjusting for age and sex. RESULTS: Among 19,986 users of glaucoma medications identified, there were 684 cases of HSV/HZV keratitis. There was no increased risk of HSV/HZV keratitis recurrence for any of the four glaucoma medications classes individually or collectively when adjusted for age and sex. There was also no increased risk for redeveloping either HSV keratitis only or HZV keratitis only amongst all anti-glaucoma users. CONCLUSION: There is no association between the use of topical ocular hypotensive therapies and HSV/HZV keratitis recurrence. Further studies are needed to confirm these findings.

Ex Vivo Evaluation of a Pressure-Sensitive Device to Aid Big Bubble Intrastromal Dissection in Deep Anterior Lamellar Keratoplasty.

Purpose: To develop and perform ex vivo testing for a device designed for semiquantitative determination of intracorneal dissection depth during big bubble (BB) deep anterior lamellar keratoplasty. Methods: A prototype device connected to a syringe and cannula was designed to determine depth of intrastromal placement based on air rebound pressure emitted by a software controlled generator. Ex vivo testing of the device was conducted on human corneas mounted on an artificial anterior chamber in three experiments: (1) cannula purposely introduced at different depths measured with anterior segment optical coherence tomography, (2) cannula introduced as per the BB technique, and (3) simulation of the BB technique guided by the device. Results: A positive pressure differential and successful BB were observed only when the cannula was positioned within 150 microns from the endothelial plane. In all successful BB cases (21/40), a repeatable increase in tissue rebound pressure was detected, which was not recorded in unsuccessful cases. The device was able to signal to the surgeon correct placement of the cannula (successful BB) in 16 of 17 cases and incorrect placement of the cannula (unsuccessful BB) in 8 of 8 cases (94.1% sensitivity, 100% specificity). Conclusions: In our ex vivo model, this novel medical device could reliably signal cannula positioning in the deep stroma for effective pneumatic dissection and possibly aid technical execution of BB deep anterior lamellar keratoplasty. Translational Relevance: A medical device that standardizes big bubble deep anterior lamellar keratoplasty could increase the overall success rate of the surgical procedure and aid popularization of deep anterior lamellar keratoplasty.

Delayed Topographical and Refractive Changes Following Corneal Cross-Linking for Keratoconus.

Background: The aim of this study was to analyze the long-term topographic and refractive outcomes of corneal cross-linking (CXL) in keratoconus. Methods: We used a retrospective observational study of patients with keratoconus who underwent CXL with a minimum follow-up of 5 years. Patients' refractive and topography data (corrected distance visual acuity, sphere, cylinder, average and maximum keratometry, and corneal aberrations) were collected. Results: A total of 112 patients/150 eyes (mean age: 33.2 ± 10.7 years; range: 13−61) were included. The mean follow-up was 5.87 ± 1.35 years (range: 5−10). At the last follow-up visit, an improvement in CDVA, spherical and cylindrical refraction, average and steepest keratometry, and corneal aberrations were observed (p < 0.05), with the exception of trefoil. At the last visit, 49 (34.8%) and 31 (22.0%) eyes had an improvement beyond 1D in their spherical and cylindrical power, respectively, and 43 (28.7%) eyes had a flattening of their steepest keratometry. Progressive improvement over time was observed for spherical refraction; max and mean-K; as well as corneal RMS, total, high, coma, and spherical aberrations (p < 0.05). More severe disease at the baseline correlated with an improvement in corneal aberrations over time. Conclusions: In addition to a progressive improvement in refractive and keratometric indices, corneal aberrations also demonstrate a steady decline with long-term follow-up after CXL, which was more pronounced in more severe patients.

Thygeson's superficial punctate keratitis.

PURPOSE: Thygeson's superficial punctate keratitis (TSPK) is a chronic and recurrent corneal epitheliopathy. Although first described more than 70 years ago, the precise etiological mechanism and optimal treatment approach for TSPK has not been established. In this paper, we present an up-to date review of the literature and propose a step-by-step management protocol. METHOD: A literature search was done on PubMed using keywords including Thygeson's superficial punctate keratitis, punctate keratitis, etiology, management, and treatment. The literature was reviewed and reported. RESULTS: The main findings of this review include a summary of the main theories behind the cause TSPK; although topical corticosteroids remain the treatment of choice, long-term risks associated with these agents and recent studies have revealed immunomodulatory agents as promising treatment adjuvants or alternatives for TSPK; surgical interventions such as PRK/PTK have been utilized in selected refractory cases; finally we propose a treatment protocol based the best available evidence and clinical experience. CONCLUSION: Although the clinical features of TSPK have been well described, the specific cause of TSPK remains inconclusive. Mechanisms proposed including viral infection, immune-mediated, and immune responses to viral infection but require further investigation. More prospective randomized clinical trials comparing efficacy of corticosteroids, tacrolimus, and cyclosporine A (CSA) are required. More evidence is required for surgical interventions such as PRK/PTK.

Delayed-onset Bilateral Peripheral Posterior Interstitial Keratitis Associated with Epstein-Barr Virus-Induced Infectious Mononucleosis.

INTRODUCTION: Epstein-Barr Virus (EBV) has been previously reported to cause rare occurrence of mostly epithelial and nummular keratitis. We hereby report two patients developing bilateral peripheral deep interstitial keratitis following EBV-related infectious mononucleosis (IM). DESCRIPTION OF CASES: Two female adolescents presented with findings of chronic relapsing posterior interstitial keratitis with neovascularisation mostly located in the superior and inferior peripheral cornea, in absence of signs of anterior uveitis. The disease presented months after the occurrence of IM. Other etiologies of interstitial keratitis were excluded. EBV DNA could not be detected in the aqueous humor of both patients. The patients responded promptly to topical corticosteroids, with multiple recurrences reported in one case. CONCLUSION: EBV-induced IM can cause bilateral peripheral interstitial keratitis with delayed onset. Progressive relapsing course of the keratitis can be observed.