The Importance of Signal Strength Index in Optical Coherence Tomography Angiography: A Study of Eyes with Pseudoexfoliation Syndrome.

Purpose: To evaluate the effect of the signal strength index (SSI) on a comparison of the vascular and structural OCT measurements between eyes with pseudoexfoliation syndrome (PXF) and healthy controls of Asian-Indian origin. Methods: In this cross-sectional study, 33 eyes of 33 PXF patients and 40 healthy eyes of 40 controls underwent OCT and OCT angiography (OCTA). Eyes with intraocular pressure (IOP) >21mmHg, glaucomatous disc changes, or any other ocular pathology were excluded. Peripapillary vessel density (VD) and retinal nerve fiber layer (RNFL) thickness were determined from the optic disc scans. Parafoveal VD and ganglion cell complex (GCC) thickness were measured from the macular scans. These parameters were compared between the groups using mixed effect models after adjusting for clinical confounders such as IOP, as well as SSI of the scans. Results: The 2 groups were demographically similar. Average RNFL (94µm vs 100µm, p = 0.01) and GCC (91µm vs 95µm, p = 0.03) were thinner in the PXF group compared to controls. The average peripapillary VD appeared lower in the PXF groups compared to controls (58.2% vs 58.8%, p = 0.04), but after adjusting for IOP and SSI, no difference was noted (p = 0.39). After accounting for confounders, parafoveal VD in the PXF group was significantly lower compared to controls (44.3% vs 46.8%, p = 0.008). Conclusion: Peripapillary RNFL thickness, parafoveal GCC thickness and parafoveal VD were decreased in eyes with PXF when compared to controls. VD measurements are associated with the SSI and, therefore, clinicians and researchers evaluating OCTA scans quantitatively must consider the SSI value during analysis and interpretation.

Eight and a Half Syndrome: A Rare Case of Pontine Infarction.

INTRODUCTION: This case report describes "one-and-a-half" syndrome with supranuclear facial palsy. CASE: 39 years old male hypertensive patient presented with right facial nerve palsy, internuclear ophthalmoplegia and conjugate gaze palsy. Neuroimaging showed acute posterior pontine infarct at medial longitudinal fasciculus, paramedian pontine reticular formation, abducens nerve nucleus and seventh nerve fascicular zone. OBSERVATION: "One-and-a-half"syndrome is characterized by a lateral gaze palsy in one direction and internuclear ophthalmoplegia in the other. Our patient had Right sided one and a half syndrome along with the right facial nerve palsy. CONCLUSION: Eight and a half syndrome is a rare manifestation of pontine infarction.

Floral Pattern of Keratic Precipitates in Vitreoretinal Lymphoma on In Vivo Confocal Microscopy.

PURPOSE: To describe the morphological patterns of keratic precipitates (KPs) in vitreoretinal lymphoma (VRL) using in vivo confocal microscopy (IVCM). METHODS: Six eyes of three biopsy-proven VRL patients were included. KPs were identified and analyzed on IVCM. RESULTS: On examination, pigmented KPs in four eyes, white central KPs in two eyes and anterior chamber cells with flare in six eyes and pseudo hypopyon in one eye were identified. A typical floral pattern of KPs on IVCM was noted in all eyes. Three eyes each showed the complete and incomplete floral patterns, respectively. Resolution of KPs on IVCM was noted after chemotherapy. CONCLUSION: In addition to the routinely used clinical and imaging markers like the visual acuity, presence of lymphomatous cells in the vitreous and optical coherence tomography findings, the presence and appearance of KPs on IVCM can also be considered as a useful, diagnostic and treatment monitoring marker in VRL.

Optical Coherence Tomography Angiography and Visual Field Progression in Primary Angle Closure Glaucoma.

PRECIS: Lower whole enface disc (coefficient: 0.02, P=0.03) and macular vessel densities (coefficient: 0.04, P=0.02) on optical coherence tomography angiography (OCTA) were significantly associated with faster rate of mean deviation (MD) decline. PURPOSE: To evaluate the association between OCTA features and prior visual field (VF) progression in primary angle closure glaucoma (PACG). METHODS: In a cross-sectional study, 46 eyes of 31 PACG patients with 5 reliable VF examinations performed over ≥3 years of follow-up underwent OCTA imaging. Effect of clinical (age, sex, number of antiglaucoma medications, mean, and SD of intraocular pressure during follow-up), optical coherence tomography (average retinal nerve fiber layer and ganglion cell complex thickness) and OCTA (whole enface vessel density of disc and macular scan, deep-layer microvascular dropout) parameters on the rate of MD change was evaluated using linear mixed models. RESULTS: Average (±SD) MD of the baseline VF was -7.4±7.3 dB, and rate of MD change was -0.32±0.29 dB/y. Whole enface vessel density of disc and macular scans was 39.5%±8.1% and 38.7%±4.4%, respectively. Microvascular dropout was noted in 33.3% of the eyes. Multivariate mixed models showed that lower whole enface disc (coefficient: 0.02, P=0.03) and macular vessel densities (coefficient: 0.04, P=0.02) were significantly associated with faster rate of MD decline. Other factors significantly associated with faster progression in multivariate models were older age (coefficient: -0.02, P<0.05) and the presence of systemic hypertension (coefficient: -0.37, P=0.01) and diabetes (coefficient: -0.28, P=0.05). CONCLUSIONS: Lower superficial vessel density measured using OCTA was significantly associated with faster VF progression in PACG. In these eyes, OCTA parameters can serve as biomarker suggestive of past VF progression.