Primary open-angle glaucoma (POAG) is characterized by degeneration of retinal ganglion cells associated with an increase in intraocular pressure (IOP) due to hindered aqueous humor (AH) drainage through the trabecular meshwork and uveoscleral pathway. Polyunsaturated fatty acids and oxylipins are signaling lipids regulating neuroinflammation, neuronal survival and AH outflow. Among them, prostaglandins have been previously implicated in glaucoma and employed for its treatment. This study addressed the role of signaling lipids in glaucoma by determining their changes in AH accompanying IOP growth and progression of the disease. Eye liquids were collected from patients with POAG of different stages and cataract patients without glaucoma. Lipids were identified and quantified by UPLC-MS/MS. The compounds discriminating glaucoma groups were recognized using ANCOVA and PLS-DA statistic approaches and their biosynthetic pathways were predicted by bioinformatics. Among 22 signaling lipids identified in AH, stage/IOP-dependent alterations in glaucoma were provided by a small set of mediators, including 12,13-DiHOME, 9- and 13-HODE/KODE, arachidonic acid and lyso-PAF. These observations correlated with the expression of cytochromes P450 (CYPs) and phospholipases A2 in the ocular tissues. Interestingly, tear fluid exhibited similar lipidomic alterations in POAG. Overall, POAG may involve arachidonic acid/PAF-dependent pathways and oxidative stress as evidenced from an increase in its markers, KODEs and 12,13-DiHOME. The latter is a product of CYPs, one of which, CYP1B1, is known as POAG and primary congenital glaucoma-associated gene. These data provide novel targets for glaucoma treatment. Oxylipin content of tear fluid may have diagnostic value in POAG.

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В обзоре литературы представлены сведения об анатомо-физиологических особенностях строения сосудов конъюнктивы, радужки, цилиарного тела. Приведены данные, касающиеся разработки и применения новых, неинвазивных методов исследования гемодинамики в микрососудах переднего отрезка глаза. Для изучения кровотока переднего отрезка глаза в последние годы используют биомикроскопию, фотографирование и видеобиомикроскопию, телевизионную биомикроскопию сосудов, темнопольную визуализацию, аппликационную флюоресцентную ангиографию, фотоакустическую ангиографию, ортогональную поляризационную спектроскопию, лазерную допплеровскую флоуметрию и ОКТ-ангиографию. Эти методы позволяют определять качественные и количественные характеристики состояния микроциркуляции конъюнктивы, радужки, цилиарного тела и являются высокоинформативными для оценки влияния различных лекарственных препаратов на сосудистую систему глаза. Исследование состояния гемодинамики в микрососудах глаза необходимо для фундаментального подхода к изучению патофизиологии системных нарушений кровообращения (при артериальной гипертензии, сахарном диабете и др.) и изменений регионарного кровотока при заболеваниях органа зрения. Мониторинг микроциркуляции переднего отрезка глаза в клинической практике дает возможность контролировать эффективность медикаментозного воздействия и хирургического лечения.

The review is focused on modern methods of instrumental diagnostics of primary open-angle glaucoma. Diagnostic possibilities and informativeness of objective measurable parameters are discussed with regard to special criteria, called clinical endpoints.

Purpose: to determine the changes in electrophysiological parameters reflecting specific dysfunctions of retinal ganglion cells (RGCs) at advanced stages of glaucomatous optic neuropathy (GON).Material and methods. The study involved 35 patients (55 eyes) aged 51–76 (63.1 ± 7.7 years) with primary open-angle glaucoma (POAG), divided into two subgroups depending on POAG stages: developed (24 patients, 27 eyes) and advanced stages (24 patients, 28 eyes). The age-matched control group (aged 51–72, 59.8 ± 5.9) included 28 relatively healthy individuals (32 eyes). Transient and steady-state pattern ERG (PERG) and photopic negative response (PhNR) were recorded according to ISCEV standards.Results. A decrease in the amplitude of the transient PERG's N95 and P50-waves and steady-state PERG was found, the degree of which showed an inverse dependence on the angular size of the stimulus, which clearly distinguished the developed and advanced POAG stages from the initial GON. The developed stages are characterized by a decrease in the PhNR amplitude, calculated from the baseline, and the PhNR/b index, the reduction of which was the more significant the greater the intensity of the flash. A significant delay of the N95 peak for patterns of all angular sizes and a less pronounced lengthening of the latency of the P50 wave (significant only for small stimuli 0.8° and 0.3°) in comparison with the age norm were found. The latencies of the steady-state PERG and PhNR practically did not differ from the age norm values.Conclusion. The revealed reduction in the amplitudes of N95 and P50 waves of transient and steady-state PERG, PhNR, and the PhNR/b index, as well as an increase in the peak latency of N95 and P50 waves of transient PERG, may be markers of functional changes in the retina associated with non-adaptive plasticity or reflecting a combination of the processes of adaptive plasticity and degeneration of RGCs. Further research in this area will help give a more accurate characterization of the found regularities and apply the obtained results in clinical practice.