Clinical pathology and diagnostics of nystagmus

Optical nystagmus is an involuntary oscillatory movement. Nystagmus can occur as an isolated nosology and lead to decreased visual functions in combination with other pathologies. A decreased visual function, including visual acuity, is observed in many patients with optic nystagmus. Patients with optical nystagmus were noted by ophthalmologists with a significant difference in the acuity of monocular and binocular vision, which is much higher in the second case. As a rule, a difference is observed in visual acuity in the straight and forced position of the head. Frequently, nystagmus is combined with refractive errors. Some authors consider astigmatism the most common form of ametropia in nystagmus, and nystagmus itself, a predisposing factor for the presence of astigmatism. An important task in diagnostics is the quantitative eye movement assessments since the tactics of treatment and the prognosis of the course of the disease depend on this. One of the problems in the examination of patients with nystagmus is the assessment of the fundal condition. Modern optical coherence tomographs are helpful in the objective diagnostics of retinal structures of the posterior pole of the eye, as well as improved software, such as the Eye Tracking system, and an increased scanning speed allowed reliable studies even with spontaneous oscillatory eye movements and a significantly decreased visual acuity. With nystagmic relative amblyopia, both photosensitivity and fixation were violated, which may indicate the presence of organic changes in the central parts of the retina and a primary fixation violation.