Trends in Corneal Transplantation in a Tertiary Hospital in Brazil

Management of keratoconus: an updated review

Keratoconus is the most common corneal ectatic disorder. It is characterized by progressive corneal thinning with resultant irregular astigmatism and myopia. Its prevalence has been estimated at 1:375 to 1:2,000 people globally, with a considerably higher rate in the younger populations. Over the past two decades, there was a paradigm shift in the management of keratoconus. The treatment has expanded significantly from conservative management (e.g., spectacles and contact lenses wear) and penetrating keratoplasty to many other therapeutic and refractive modalities, including corneal cross-linking (with various protocols/techniques), combined CXL-keratorefractive surgeries, intracorneal ring segments, anterior lamellar keratoplasty, and more recently, Bowman's layer transplantation, stromal keratophakia, and stromal regeneration. Several recent large genome-wide association studies (GWAS) have identified important genetic mutations relevant to keratoconus, facilitating the development of potential gene therapy targeting keratoconus and halting the disease progression. In addition, attempts have been made to leverage the power of artificial intelligence-assisted algorithms in enabling earlier detection and progression prediction in keratoconus. In this review, we provide a comprehensive overview of the current and emerging treatment of keratoconus and propose a treatment algorithm for systematically guiding the management of this common clinical entity.

A Framework for Human Corneal Endothelial Cell Culture and Preliminary Wound Model Experiments with a New Cell Tracking Approach

Cell injection therapy is emerging as an alternative to treat corneal endothelial dysfunction (CED) and to avoid corneal scarring due to bullous keratopathy. However, establishing a standardized culture procedure that provides appropriate cell yield while retaining functional features remains a challenge. Here, we describe a detailed framework obtained from in vitro culture of human corneal endothelial cells (HCECs) and comparative in vivo experimental models for CED treatment with a new cell tracking approach. Two digestion methods were compared regarding HCEC morphology and adhesion. The effect of Y-27632 (ROCKi) supplementation on final cell yield was also assessed. Cell adhesion efficacy with two cell delivery systems (superparamagnetic embedding and cell suspension) was evaluated in an ex vivo human cornea model and in an in vivo rabbit CED model. The injection of supplemented culture medium or balanced salt solution (BSS) was used for the positive and negative controls, respectively. HCEC isolation with collagenase resulted in better morphology and adhesion of cultured HCEC when compared to EDTA. Y-27632 supplementation resulted in a 2.6-fold increase in final cell yield compared to the control. Ex vivo and in vivo adhesion with both cell delivery systems was confirmed by cell tracker fluorescence detection. Corneal edema and opacity improved in both animal groups treated with cultured HCEC. The corneas in the control groups remained opaque. Both HCEC delivery systems seemed comparable as treatments for CED and for the prevention of corneal scarring.

Diagnosis and Management of Keratoconus-A Narrative Review of Clinicians' Perspectives

This review discusses the current practices, attitudes, and trends in diagnosing and managing keratoconus (KC) in adults and children by optometrists and ophthalmologists in order to highlight the differences on a global scale. Two independent reviewers searched the electronic databases and grey literature for all potential articles published from 1 January 2000 to 1 June 2022 on management of KC. Keywords used in searches included "keratoconus", "diagnosis", "management", "treatment", "attitude", "practices", "opinion", "optometrist", "ophthalmologist", "consensus", and "protocol". A total of 19 articles was included in this review-12 from the database search and seven from the grey literature. Although a common stepwise approach of non-surgical management was noted, there were differences in the rates of prescribing rigid gas permeable lenses. Furthermore, while clinicians agreed on the need for early diagnosis, the timeline and type of referral varied significantly. A similar discordance was found in the milestones for surgical intervention and preferred surgical techniques. Practice patterns in keratoconus diagnosis and management vary throughout the world. Multiple recommendations and suggestions to minimise the differences have been provided in the literature, with the main themes being improvement in education, interdisciplinary patient care, and further research to reach consensus.

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.