Vision outcomes in dogs with primary glaucoma surgically treated with lensectomy and endolaser cyclophotocoagulation after an Ahmed valve gonioimplantation failure.

OBJECTIVE: The aim of this study was to retrospectively evaluate vision outcomes of dogs with primary angle closure glaucoma (PACG) that underwent Ahmed valve gonioimplantation (AVG) followed by lensectomy and endolaser cyclophotocoagulation (ECP) with or without bleb resection after AVG failure. PROCEDURE: Medical records from 2008 to April 2022 were reviewed. All patients selected had an AVG performed first. Following valve failure, lensectomy-ECP was performed in addition to bleb resection as indicated. Additional ECP and AVG replacement surgeries were performed as deemed medically necessary. Main outcomes evaluated included vision preservation, average IOP reduction, and the number of glaucoma medications (both oral and topical) at 6, 12, 24, and 36 months. RESULTS: Fourteen eyes from 13 patients were included in the study. Females were predominant (n = 9) compared with males (n = 4). Mean age at initial glaucoma diagnosis was 6.82 years. Following AVG and lensectomy-ECP, vision was preserved in 93%, 84%, 60%, and 48% of eyes at 1, 2, 3, and 4 years respectively. Following lensectomy-ECP, there was a significant reduction in mean IOP of 9.64 mmHg (p = .015) and 9.71 mmHg (p = .016) at 2 and 6 months, respectively. There was a reduction in mean IOP of 2.45, 7.25, and 12.25 mmHg at 12, 24, and 36 months, respectively, which was not statistically significant. There was a significant decrease in the number of glaucoma medications at all evaluated time points except 24 months. CONCLUSIONS: Combined AVG and lensectomy-ECP is successful in maintaining vision long term as well as decreasing IOP, and the number of glaucoma medications administered.

Acremonium and trichosporon fungal keratoconjunctivitis in a Leopard Gecko (Eublepharis macularius).

A 6-year-old male leopard gecko (Eublepharis macularius) was presented with a 2-year history of recurrent dysecdysis involving the ocular surface of both eyes. Ophthalmic examination revealed ocular surface desiccation and multifocal superficial ulcerative keratitis with patchy remnants of retained shed. Other abnormalities included stomatitis and mandibular and maxillary osteomyelitis. Topical and systemic antibiotic therapy, oral vitamin A, and improved husbandry conditions resolved the stomatitis and osteomyelitis but did not improve the ocular surface. Corneal cytology collected with a cytobrush revealed branching hyphae and budding yeast consistent with fungal keratitis. Fungal culture grew Acremonium sp. and Trichosporon sp. The addition of topical antifungal therapy improved the ocular surface health, but the patient was euthanized 7 weeks after initial presentation for persistent vomiting and dyspnea. Necropsy was declined. This case describes the first case of fungal keratitis caused by Acremonium sp. and Trichosporon sp. in a reptile.

Comparison of chorioretinal layers in rhesus macaques using spectral-domain optical coherence tomography and high-resolution histological sections.

Nonhuman primates are important preclinical models of retinal diseases because they uniquely possess a macula similar to humans. Ocular imaging technologies such as spectral-domain optical coherence tomography (SD-OCT) allow noninvasive, in vivo measurements of chorioretinal layers with near-histological resolution. However, the boundaries are based on differences in reflectivity, and detailed correlations with histological tissue layers have not been explored in rhesus macaques, which are widely used for biomedical research. Here, we compare the macular anatomy and thickness measurements of chorioretinal layers in rhesus macaque eyes using SD-OCT and high-resolution histological sections. Images were obtained from methylmethacrylate-embedded histological sections of 6 healthy adult rhesus macaques, and compared with SD-OCT images from 6 age-matched animals. Thicknesses of chorioretinal layers were measured across the central 3 mm macular region using custom semi-automated or manual software segmentation, and compared between the two modalities. We found that histological sections provide better distinction between the ganglion cell layer (GCL) and inner plexiform layer (IPL) than SD-OCT imaging. The first hyperreflective band between the external limiting membrane (ELM) and retinal pigment epithelium (RPE) appears wider on SD-OCT than the junction between photoreceptor inner and outer segments seen on histology. SD-OCT poorly distinguishes Henle nerve fibers from the outer nuclear layer (ONL), while histology correctly identifies these fibers as part of the outer plexiform layer (OPL). Overall, the GCL, inner nuclear layer (INL), and OPL are significantly thicker on histology, especially at the fovea; while the ONL, choriocapillaris (CC), and outer choroid (OC) are thicker on SD-OCT. Our results show that both SD-OCT and high-resolution histological sections allow reliable measurements of chorioretinal layers in rhesus macaques, with distinct advantages for different sublayers. These findings demonstrate the effects of tissue processing on chorioretinal anatomy, and provide normative values for chorioretinal thickness measurements on SD-OCT for future studies of disease models in these nonhuman primates.

In Vivo Multimodal Imaging of Drusenoid Lesions in Rhesus Macaques.

Nonhuman primates are the only mammals to possess a true macula similar to humans, and spontaneously develop drusenoid lesions which are hallmarks of age-related macular degeneration (AMD). Prior studies demonstrated similarities between human and nonhuman primate drusen based on clinical appearance and histopathology. Here, we employed fundus photography, spectral domain optical coherence tomography (SD-OCT), fundus autofluorescence (FAF), and infrared reflectance (IR) to characterize drusenoid lesions in aged rhesus macaques. Of 65 animals evaluated, we identified lesions in 20 animals (30.7%). Using the Age-Related Eye Disease Study 2 (AREDS2) grading system and multimodal imaging, we identified two distinct drusen phenotypes - 1) soft drusen that are larger and appear as hyperreflective deposits between the retinal pigment epithelium (RPE) and Bruch's membrane on SD-OCT, and 2) hard, punctate lesions that are smaller and undetectable on SD-OCT. Both exhibit variable FAF intensities and are poorly visualized on IR. Eyes with drusen exhibited a slightly thicker RPE compared with control eyes (+3.4 µm, P=0.012). Genetic polymorphisms associated with drusenoid lesions in rhesus monkeys in ARMS2 and HTRA1 were similar in frequency between the two phenotypes. These results refine our understanding of drusen development, and provide insight into the absence of advanced AMD in nonhuman primates.

Feeding induces translocation of vacuolar proton ATPase and pendrin to the membrane of leopard shark (Triakis semifasciata) mitochondrion-rich gill cells.

In this study we characterized mitochondrion-rich (MR) cells and regulation of acid/base (A/B) relevant ion-transporting proteins in leopard shark (Triakis semifasciata) gills. Immunohistochemistry revealed that leopard shark gills posses two separate cell populations that abundantly express either Na⁺/K⁺-ATPase (NKA) or V-H⁺-ATPase (VHA), but not both ATPases together. Co-immunolocalization with mitochondrial Complex IV demonstrated, for the first time in shark gills, that both NKA- and VHA-rich cells are also MR cells, and that all MR cells are either NKA- or VHA-rich cells. Additionally we localized the anion exchanger pendrin to VHA-rich cells, but not NKA-rich cells. In starved sharks, VHA was localized throughout the cell cytoplasm and pendrin was present at the apical pole (but not in the membrane). However, in a significant number of gill cells from fed leopard sharks, VHA translocated to the basolateral membrane (as previously described in dogfish), and pendrin translocated to the apical membrane. Our results highlight the importance of translocation of ion-transporting proteins to the cell membrane as a regulatory mechanism for A/B regulation.