FEATURES OF FUNCTIONAL DIAGNOSTICS OF OPTIC NERVE DAMAGE IN CASE OF HEAD INJURY

Abstract

Introduction. Traumatic optic nerve damage is a rare complication of a head injury. Symptoms of primary damage appear at the time of first diagnostic in the early period and mask TON’s signs. Understanding of visual disturbances for the patient comes in a later period, when recovery is limited due to the irreversibility of the received injuries. Difficulties of early diagnosis of optic nerve damage in case of head trauma encourage the search for new, more informative methods. The aim of the study was to analyze the functional manifestations of the optic nerve damage in case of head injuries with different localization. Materials and methods. 366 cases (732 eyes) of patients with traumatic optic neuropathy (TON) were studied according to archival data in the period from 2014 to 2019. The control group consisted of 58 practically healthy persons (116 eyes). All patients were divided into three groups: A group - patients with traumatic brain injury (TBI) was 120 persons, B group - patients with craniofacial injury (CFI) - 118 persons and C group - with combined injuries - 128 injured. The degree of optic nerve damage was assessed using visometry, pupillometry, and perimetry. Results. In case of craniocerebral injury, decrease of visual acuity with an average value of 0.92±0.06 corresponded to degrees 0 (93%) and I (7%). In the case of craniofacial trauma, according to the research, visual acuity decreased to 0.76±0.13 (by 0.24, 24% compared to the control group, p<0.05). The first degree (23%) and the second degree (7%) were determined. With a combined primary head injury, visual acuity decreased to 0.42±0.21 (by 0.58, 58%, compared to the control group, p<0.05). One third were patients with I, II and III degrees of visual impairment. The use of static perimetry made it possible to detect damage to the optic nerve in patients with 0 degrees of reduced visual acuity. At the same time, 88% of patients of A group (n=120) had 0A class, 23% of B group (n=118) had 0B class, and in C group (n=122) there was almost no. The relative afferent pupillary defect’s test was negative at 0A group of vision loss, but the pupil cycle speed (PSC) was reduced in all patients. This confirms damage to the optic nerve in patients with high visual acuity This study showed that patients with TBI had high visual acuity in 93% of cases, The visual acuity was around 0.5-1.0, but sensitivity in the central part of the visual field decreased by 12 times, and the pupil reaction rate decreased by 55% compared to the control group. In case of craniofacial trauma (B group), visual acuity decreased to 0.76±0.13 (by 0.24, 24% compared to the control group, p<0.05). I degree (23%) and II degree (7%) decrease of visual acuity was determined. As for the sensitivity in the central part of the visual field, it was 46.59% lower than in the A group. In patients with a combined injury of the head and face, a third of the injured had visual acuity less than 0.1, which is not found in other variants of injury. Conclusions. Analysis showed that severity of optic nerve damage depends on localization of the head injury. The use of static perimetry and pupillometry is important for the early diagnosis of TON in conditions with high visual acuity when other symptoms are weak or not amenable to examination.