Hemi- and Central Retinal Vein Occlusion Associated with COVID-19 Infection in Young Patients without Known Risk Factors.

PURPOSE: Venous thromboembolic complications have been reported in association with coronavirus disease 2019 (COVID-19) infection. We raised awareness regarding a potential temporal association between COVID-19 infection and retinal vein occlusion (RVO). DESIGN: Multicenter, retrospective, nonconsecutive case series. SUBJECTS: Patients presenting with hemi-RVO (HRVO) or central RVO (CRVO) between March 2020 and March 2021, with confirmed COVID-19 infection, were included. The exclusion criteria were as follows: age >50 years, hypertension, diabetes, glaucoma, obesity, underlying hypercoagulable states, and those requiring intubation during hospitalization. METHODS: This was a multicenter, retrospective, nonconsecutive case series including patients presenting with hemi-RVO (HRVO) or central RVO (CRVO) between March 2020 and March 2021, with confirmed COVID-19 infection. The exclusion criteria were as follows: age >50 years, hypertension, diabetes, glaucoma, obesity, underlying hypercoagulable states, and those requiring intubation during hospitalization. MAIN OUTCOME MEASURES: Ophthalmic findings, including presenting and final visual acuity (VA), imaging findings, and clinical course. RESULTS: Twelve eyes of 12 patients with CRVO (9 of 12) or HRVO (3 of 12) after COVID-19 infection were included. The median age was 32 years (range, 18-50 years). Three patients were hospitalized, but none were intubated. The median time from COVID-19 diagnosis to ophthalmic symptoms was 6.9 weeks. The presenting VA ranged from 20/20 to counting fingers, with over half (7 of 12) having a VA of ≥20/40. OCT revealed macular edema in 42% of the eyes; of these, 80% (4 of 5) were treated with anti-VEGF injections. Ninety-two percent (11 of 12) had partial or complete resolution of ocular findings at final follow-up. Four eyes (33%) had retinal thinning, as determined using OCT, by the end of the study interval. The final VA ranged from 20/20 to 20/60, with 11 of the 12 (92%) eyes achieving a VA of ≥20/40 at a median final follow-up period of 13 weeks (range, 4-52 weeks). CONCLUSIONS: Although we acknowledge the high seroprevalence of COVID-19 and that a causal relationship cannot be established, we reported this series to raise awareness regarding the potential risk of retinal vascular events due to a heightened thromboinflammatory state associated with COVID-19 infection.

Impact of Coronavirus Disease 2019 Restrictions on Retinal Detachment: A Multicenter Experience.

In this retrospective, multicenter study of 261 eyes (259 patients), patients who underwent rhegmatogenous retinal detachment repair during the coronavirus disease 2019 (COVID-19) post-lockdown period experienced an additional 22-day delay, leading to significantly more epiretinal membrane and proliferative vitreoretinopathy and lower single-surgery anatomic success rates. During lockdown, perfluoropropane gas was used more commonly, and pneumatic retinopexy was used more commonly in COVID-19-positive patients.

Quantitative assessment of UVA-riboflavin corneal cross-linking using nonlinear optical microscopy.

PURPOSE: Corneal collagen cross-linking (CXL) by the use of riboflavin and ultraviolet-A light (UVA) is a promising and novel treatment for keratoconus and other ectatic disorders. Since CXL results in enhanced corneal stiffness, this study tested the hypothesis that CXL-induced stiffening would be proportional to the collagen autofluorescence intensity measured with nonlinear optical (NLO) microscopy. METHODS: Rabbit eyes (n = 50) were separated into five groups including: (1) epithelium intact; (2) epithelium removed; (3) epithelium removed and soaked in riboflavin, (4) epithelium removed and soaked in riboflavin, with 15 minutes of UVA exposure; and (5) epithelium removed and soaked in riboflavin, with 30 minutes of UVA exposure. Corneal stiffness was quantified by measuring the force required to displace the cornea 500 µm. Corneas were then fixed in paraformaldehyde and sectioned, and the collagen autofluorescence over the 400- to 450-nm spectrum was recorded. RESULTS: There was no significant difference in corneal stiffness among the three control groups. Corneal stiffness was significantly and dose dependently increased after UVA (P < 0.0005). Autofluorescence was detected only within the anterior stroma of the UVA-treated groups, with no significant difference in the depth of autofluorescence between different UVA exposure levels. The signal intensity was also significantly increased with longer UVA exposure (P < 0.001). Comparing corneal stiffness with autofluorescence intensity revealed a significant correlation between these values (R(2) = 0.654; P < 0.0001). CONCLUSIONS: The results of this study indicate a significant correlation between corneal stiffening and the intensity of collagen autofluorescence after CXL. This finding suggests that the efficacy of CXL in patients could be monitored by assessing collagen autofluorescence.

Implantation of an inactive epiretinal poly(dimethyl siloxane) electrode array in dogs.

The aim of this study is to investigate the long-term, mechanical biocompatibility of a polymer microtechnology that can be used to position electrodes in close proximity to the retina. Poly(dimethylsiloxane) (PDMS) arrays were manufactured by soft-lithography at Lawrence Livermore National Laboratory. The PDMS implant measured 4 mm x 40 mm x 55-60 microm and included 4-8 electrodes. Micromolded ribs were placed at the perimetry for strength and ease of manipulation. The PDMS arrays were implanted epiretinally in four normal dogs, with a single retinal tack used in each case to hold the device on the retina. The mechanical effects of the implant were followed up after surgical implantation by photography, fluorescein angiography, optical coherence tomography (OCT), and electrophysiologic tests. An intraoperative retinal tear occurred in the first implanted dog, causing retinal detachment and necessitating termination. The remaining dogs experienced no gross complications secondary to the array implantation procedure. During the follow-up period of 2 months in one eye and 6 months in three eyes, OCT demonstrated that the arrays were in close contact with the retina. Fluorescein angiography showed good perfusion of the retina under the array. At the end of 6 months, there was no statistical difference from baseline in mean retinal thickness under the array (P=0.43) or peripapillary retinal nerve fibre layer thickness corresponding to the implanted area (P=0.34). The mean distance between the array and the retinal surface varied from 32 to 68 microm throughout the follow-up. Histopathologic evaluation of the retinal implantation site in eyes followed for 6 months showed a general preservation of the normal, layered retinal structure, except for some localized retinal thinning in two eyes, where the array frame had been in direct retinal contact. The PDMS substrate micro array is a new and promising technology that can be scaled to support a high-density retinal stimulating array. Its implantation and handling is surgically manageable, and it forms a mechanically stable, acceptable interface with the inner retinal surface.

Nanobiolistic delivery of indicators to the living mouse retina.

The development of a technique to load functional indicators into living neurons is an ongoing challenge in retinal neurophysiology. In a number of live-cell preparations, fluorescence-based indicators have been of particular importance for investigating ionic concentrations, protein localization, and other physiological parameters. In the present study, we demonstrate a novel technique that uses a modified gene gun to propel silver nanoparticles coated with indicators into live retinal neurons, and we highlight the advantages of using this technique to deliver these functional indicators.

Neural responses elicited by electrical stimulation of the retina.

PURPOSE: To study electrically elicited responses (EERs) that are produced by epiretinal stimulation of normal and degenerated retina. METHODS: Three biological models of retinal degeneration are compared: normal and rd1 mouse, normal and RCD1 dog, and human with retinitis pigmentosa. In mouse, epiretinal stimulation was accomplished by means of a wire inserted in the vitreous cavity, and single-unit activity was recorded in visual cortex. In dog and human, an implantable retinal stimulator was used to stimulate the retina, and evoked potentials were recorded from the cortical surface (dog) or scalp (human). RESULTS: Analysis of EERs revealed distinct early (less than 10 ms) and late (greater than 50 ms) responses. Synaptic blockers abolished the late response but not the early response. For eliciting the early response in normal and rd mice, a square pulse stimulus was more efficient than the sine wave or pulse train. In normal and degenerate canine retina, electrically elicited responses also exhibited early and late phases. EERs in a retinal prosthesis test subject (with retinitis pigmentosa) showed latency similar to the canine, but no evidence of an early response, possibly due to the lack of sensitivity in scalp (human) vs cortical surface (canine) electrode placement. CONCLUSION: EERs could be elicited from both normal and degenerated retina. Mouse, dog, and human EERs showed common characteristics.

Long-term stimulation by active epiretinal implants in normal and RCD1 dogs.

An epiretinal prosthesis, consisting of an extraocular microelectronic stimulator and an intraocular electrode array, was implanted in one eye of three blind and three sighted dogs. Three dogs (2 blind, 1 normal) were stimulated for 120 days, and two dogs (both normal) for 60 and 103 days respectively for 8-10 h/day at levels of 0.1 mC cm(-2) and 0.05 mC cm(-2), with each stimulus level presented to half of the array. One blind dog was kept as an inactive implant control. During the study period, electroretinograms (ERG) and fundus photographs were recorded. At the end of the study period, the dogs were sacrificed and histological and morphometric evaluation was made of the retina. No inflammatory reaction, neovascularization or hemorrhage was observed during the follow-up examinations. ERGs were unchanged. Stimulus levels used were of sufficient amplitude to elicit cortical evoked potentials. Histological evaluation showed no inflammatory infiltrates or changes in retina morphometry related to electrical stimulation when compared to the unstimulated control eye. Morphometric analysis revealed no consistent differences relating to electrical stimulation. In summary, chronic electrical stimulation of the dog retina at up to 0.1 mC cm(-2) with an epiretinal prosthesis does not appear to adversely affect the retina.

Iris recognition as a biometric method after cataract surgery.

BACKGROUND: Biometric methods are security technologies, which use human characteristics for personal identification. Iris recognition systems use iris textures as unique identifiers. This paper presents an analysis of the verification of iris identities after intra-ocular procedures, when individuals were enrolled before the surgery. METHODS: Fifty-five eyes from fifty-five patients had their irises enrolled before a cataract surgery was performed. They had their irises verified three times before and three times after the procedure, and the Hamming (mathematical) distance of each identification trial was determined, in a controlled ideal biometric environment. The mathematical difference between the iris code before and after the surgery was also compared to a subjective evaluation of the iris anatomy alteration by an experienced surgeon. RESULTS: A correlation between visible subjective iris texture alteration and mathematical difference was verified. We found only six cases in which the eye was no more recognizable, but these eyes were later reenrolled. The main anatomical changes that were found in the new impostor eyes are described. CONCLUSIONS: Cataract surgeries change iris textures in such a way that iris recognition systems, which perform mathematical comparisons of textural biometric features, are able to detect these changes and sometimes even discard a pre-enrolled iris considering it an impostor. In our study, re-enrollment proved to be a feasible procedure.

Descrição de uma ferramenta digital e de um ambiente virtual para fins de segunda opinião em oftalmologia / Description of a digital image system and a virtual environment to be used as a remote second referral option in ophthalmology

OBJETIVOS: Idealizar, desenvolver e verificar a funcionalidade um sistema de teleoftalmologia para diagnóstico remoto em casos clínicos. MÉTODOS: Descrever o funcionamento e utilização do sistema, sua capacidade de captura, arquivamento e envio de imagens via internet, e de um domínio virtual voltado ao telediagnóstico, aconselhamento ou segunda opinião. RESULTADOS: Foram definidos os requisitos básicos, detalhes de programação e de funcionamento de um programa de captura de imagens. O funcionamento do mesmo acoplado a uma placa de captura de imagens foi realizado com sucesso, bem como a criação, na internet, de um domínio médico-oftalmológico. CONCLUSÃO: Os resultados preliminares permitiram a avaliação de um sistema misto para o suporte médico em nosso meio. Os instrumentos diagnósticos disponíveis bem como suas conexões com a rede foram satisfatórias e suficientes para viabilizar um estudo piloto bem su-cedido. O sistema revelou-se potencialmente adequado para o telediagnóstico e segunda opinião. O método necessita de testes clínicos e compa-ração com métodos diagnósticos tradicionais para comprovar a sua eficácia.

Reconhecimento de íris como método biométrico após cirurgiade catarata / Iris biometrics after cataract surgery

Objetivo: verificar a capacidade de reconhecimento biométrico iriano após a cirurgia de catarata. Métodos: cinqüenta e cinco olhos de cinqüenta e cinco pacientes a serem submetidos à cirurgia de catarata foram selecionados e cadastrados pelo sistema biométrico lrisAccess© da LG Electronics. Todos tiveram suas íris examinadas por biomicroscopia. Os pacientes foram, então, submetidos à facoemulsificação com implante de lente intra-ocular no Setor de Catarata da UNIFESP. Pelo menos trinta dias após o procedimento, os mesmos pacientes foram reexaminados e tiveram suas íris verificadas. Resultados: os pacientes apresentaram variados graus de diferenças de textura na camada superficial da íris, alterações no formato da pupila, perda de tecido e atrofia. Quarenta e nove olhos continuaram sendo reconhecidos, e seis perderam o cadastramento inicial, tendo tido sucesso no recadastramento do mesmo olho. Todos os olhos não-reconhecidos, exceto um, tiveram alterações irianas clinicamente importantes. As variações biométricas binárias (distância Hamming) foram estatisticamente correlacionadas com as alterações clínicas. Conclusão: o procedimento de facoemulsificação causa alterações irianas capazes de mudar, de forma estatisticamente significante, a característica dos códigos irianos provocando a não identificação biométrica

Therapeutic contact lens-related bilateral fungal keratitis.

PURPOSE: To describe a rare case of bilateral Candida keratitis after contact lens use following bilateral penetrating keratoplasty (PK). METHODS: A 40-year-old female with a clinical diagnosis of Sjögren's syndrome was being followed for corneal thinning in both eyes. She suffered a spontaneous bilateral perforation and underwent penetrating keratoplasty. Therapeutic contact lenses were prescribed for both eyes owing to persistent epithelial defects. Two months later, a biomicroscopic examination revealed corneal infiltrates. RESULTS: A corneal tissue sample, saline, and contact lens cultures were all positive for Candida albicans. Topical and systemic antifungal therapy successfully cleared the infection in the right eye; however, the left eye underwent another corneal graft surgery. CONCLUSIONS: Infectious fungal keratitis may be a complication of wearing therapeutic contact lenses after PK, in a patient with Sjögren's syndrome. The pre-existing eye disease is an important associated factor in cases of yeast infection; therefore, adequate care of these patients and careful follow-up after PK are indicated as measures to prevent early infections.

Impacto econômico on tratamento do glaucoma: volume de gotas de colírio antiglaucomatosos brasileiros e norte americanos / Economic impact of glaucoma treatment: Brazilian and North-american antiglaucomatous

Objetivo: Comparar o exame de gotas de colírios antiglaucomatosos norte-americanos e brasileiros, e a repercussäo no custo do tratamento. Métodos: Estudo volumétrico da gota e consequente número de gotas por mililitro, com estabelecimento da duraçäo média de cada frasco de colírio para a posologia e custo anual do tratamento. Resultados: A gota de Alphagan brasileiro foi em média 18 por cento maior que a norte-americana, com duraçäo média de 30,8 dias e custo anual de R$ 440,70; o Alphagan norte-americano teve duraçäo média de 36,3 dias e custo anual de R$374,10, ou seja, 17,8 por cento de diferença no custo anual. A gota de Betoptic S brasileiro foi 38,4 por cento maior que a norte-americana, com duraçäo de 31,3 dias e custo anual de R$ 192,60; o Betoptic S norte-americano teve duração de 43,3 dias e custo anual deR$139,40, ou seja, 38,1 por cento de diferença no custo anual. A gota de Iopidine brasileiro foi 46,3 por cento maior que a norte-americana, com duraçäo de 35,7 dias e custo anual de R$ 365,00; o Iopidine'" norte-americano teve duraçäo de 52,6 dias e custo anual de R$ 248,40, ou seja, 46,9 por cento de diferença no custo anual. A gota de Timoptol foi 14,7 por cento maior que a norte-americana, com duraçäo de 45,4 dias e custo anual de R$ 58,40; o Timoptic norte- americano teve duraçäo de 52,1 dias e custo anual de R$ 51,00, ou seja, 14,5 por cento de diferença no custo anual. Conclusöes: Em todos os colírios D volume da gota brasileira foi estatisticamente maior, acarretando menor duração do frasco, maior custo anual do tratamento com desperdício significativo e prejuízo para o consumidor.