Course and structure of corneal nerve fibers in patients with primary open-angle glaucoma

   PURPOSE. T o analyze the course and structure of corneal nerve fibers (CNF) in patients with different stages of primary open-angle glaucoma (POAG), and to determine possible correlations with the available diagnostic indicators of glaucoma progression.   METHODS.  The study included 48 patients (48 eyes) diagnosed with stages I–IV POAG at the age of 33 to 75 years. In addition to standard examination methods, all patients underwent static perimetry with Humphrey Field Analyzer II, optical coherence tomography (OCT) of the optic disc, measurement of biomechanical properties of the fibrous membrane of the eye, as well as laser confocal microscopy of the cornea on HRT III device with corneal adapter Cornea Rostock.   RESULTS. There were positive correlations of medium strength between the indices of basic nerve fiber length (r = 0.64 and r = 0.63; p < 0.05) and density (r = 0.6 and r = 0.65; p < 0.05) with perimetry data (MD and PSD) and retinal nerve fiber thickness measured with OCT of the optic disc (r = 0.65 and r = 0.61; p < 0.05). Nerve fiber anisometry and symmetry coefficients depended on glaucoma stage (r = 0.62 and r = 0.65; p < 0.05). An increase in the number and density of Langerhans cells and an increase in the length of their processes were detected. A reliable correlation (r = 0.63) was found between glaucoma stage and corneal inflammatory response. The immune etiology of the glaucoma process considered by several authors may be a reason of an increase in the number and density of macrophages during the progression of POAG.   CONCLUSION. Laser confocal microscopy can be used as an additional diagnostic method for patients with different stages of POAG.