Search Results

Abstract

PURPOSE: Timely screening and treatment are essential for preventing diabetic retinopathy blindness. Improving screening workflows can reduce waiting times for specialist evaluation and thus enhance patient outcomes. This study assessed different screening approaches in a Brazilian public healthcare setting.
METHODS: This retrospective study evaluated a telemedicine-based diabetic retinopathy screening implemented during the COVID-19 pandemic and compared it with in-person strategies. The evaluation was conducted from the perspective of a specialized referral center in an urban area of Central-West Brazil. In the telemedicine approach, a trained technician would capture retinal images by using a handheld camera. These images were sent to specialists for remote evaluation. Patient variables, including age, gender, duration of diabetes diagnosis, diabetes treatment, comorbidities, and waiting time, were analyzed and compared.
RESULTS: In total, 437 patients with diabetes mellitus were included in the study (mean age: 62.5 ± 11.0 years, female: 61.7%, mean diabetes duration: 15.3 ± 9.7 years, insulin users: 67.8%). In the in-person assessment group, the average waiting time between primary care referral and specialist evaluation was 292.3 ± 213.9 days, and the referral rate was 73.29%. In the telemedicine group, the average waiting time was 158.8 ± 192.4 days, and the referral rate was 29.38%. The telemedicine approach significantly reduced the waiting time (p<0.001) and significantly lowered the referral rate (p<0.001).
CONCLUSION: The telemedicine approach significantly reduced the waiting time for specialist evaluation in a real-world setting. Employing portable retinal cameras may address the burden of diabetic retinopathy, especially in resource-limited settings.

Keywords: Telemedicine/methods; Diabetic retinopathy; Diagnostic screening programs; Vision screening; Practice patterns, physicians

Abstract

Corneal blindness affects more than 12 million individuals worldwide; however, the availability of human donor corneas meets only a small fraction of the demand. Porcine corneal xenotransplantation represents a promising alternative because of the cornea's immune privilege and the anatomical similarities between human and porcine corneas. However, the galactose-α1,3-galactose antigen expressed on porcine cells induces hyperacute rejection through the activation of human anti-Gal antibodies, complement pathways, and innate immune cell infiltration. This review summarizes the mechanisms underlying corneal immune privilege and contrasts them with galactose-α1,3-galactose-mediated rejection pathways. In addition, it evaluates five major mitigation strategies: GGTA1-knockout pigs, enzymatic α-galactosidase treatment, RNA interference, decellularization, and immunosuppressive approaches, including CD40-CD154 blockade and topical tacrolimus. Preclinical studies have demonstrated that GTKO corneas can maintain transparency for longer than 1 year, whereas decellularized matrices preserve corneal architecture while exhibiting low antigenicity. These findings support the future clinical translation of porcine corneal xenotransplantation.

Keywords: Corneal transplantation; Xenotransplantation; Graft rejection; Galactose; Immunosuppressive agents.