Applications of dynamic visual acuity test in clinical ophthalmology

Dynamic visual acuity test (DVAT) plays a key role in the assessment of vestibular function, the visual function of athletes, as well as various ocular diseases. As the visual pathways conducting dynamic and static signals are different, DVATs may have potential advantages over the traditional visual acuity tests commonly used, such as static visual acuity, contrast sensitivity, and static perimetry. Here, we provide a review of commonly applied DVATs and their several uses in clinical ophthalmology. These data indicate that the DVAT has its unique clinical significance in the evaluation of several ocular disorders.

Periphery kinetic perimetry: clinically feasible to complement central static perimetry

Background Existing evidence suggests that visual field defect in eyes with glaucoma significantly varies between individuals. The following study compared the central visual field defects with the peripheral visual field defects in patients with suspect glaucoma and primary open-angle glaucoma (POAG) and investigated whether using the central visual field test alone could result in loss of clinically valuable information. Methods In this prospective observational study, 167 eyes from 89 patients with suspect glaucoma or POAG were first examined with static automated perimetry (SAP), followed by a peripheral visual field test on Octopus 900 perimeter (Haag-Streit, Koeniz, Switzerland). The peripheral visual field test was performed by “Auto Kinetic Perimetry” program, in which Goldmann III4e stimuli randomly moved along 16 vectors at a constant angular velocity of 5 deg/s. Results Glaucomatous peripheral visual field defects were seen in 18% of the eyes with a normal central visual field. In addition, 86% of glaucoma patients with moderate-to-severe central visual field defects had corresponding peripheral visual field defects in the form of localized or diffuse depression of the isopters. Furthermore, a moderate correlation was found between the central and peripheral visual fields. The median test duration was 71 s for the peripheral test and 803 s for the central test (p < 0.001). Conclusions Our study demonstrated the diversity of glaucomatous visual field defects, as well as the possibility of losing the clinically valuable information due to focusing on the central visual field test alone. The peripheral kinetic perimetry is clinically feasible to complement the central static perimetry for a comprehensive assessment of visual function in glaucoma patients.

Modern methods for assessing morphometric and functional indicators in primary glaucoma

In the article are presented analytical review of scientific articles devoted to the study of modern methods of diagnostics of primary glaucoma. On the basis of scientific articles, a review material was collected and systematized on diagnostic methods for studying morphometric and functional changes in primary glaucoma, which are used in modern ophthalmic practice. In recent years, the improvement and implementation of new high-tech modern diagnostic methods open up new opportunities for researchers and clinicians. Optical coherence tomography, OCT angiography, static perimetry make it possible, by comparing morphometric and functional parameters, to give a more complete, comprehensive assessment of pathological changes in the optic nerve head, in the macular region and at the level of the choriocapillaries. Prevention of glaucoma blindness largely depends on its early diagnosis based on the use of modern organizational and medical technologies. Key words: glaucoma, open-angle glaucoma, intraocular pressure, glaucomatous optic neuropathy, diagnostic methods.

PUPIL VISUAL TRACKING ALGORITHMS FOR AUTOMATED STATIC PERIMETRY SYSTEMS

Some diseases, for instance, a glaucoma, cause visual field defects. For the timely diagnostics of such defects, various methods are used. One of the state-of-the-art diagnostic methods is automated static perimetry. The method of static perimetry consists in the light sensitivity determination in different parts of the visual field using stationary objects of variable luminosity. When scanning the visual field in this way, an important factor is the control of gaze fixation at the fixation point. The greatest accuracy in determining the gaze fixation position is achieved by the method of the pupil visual tracking using a video camera.In this paper, four groups of visual tracking algorithms are considered: segmentation-based methods, correlation methods, methods based on optical flow and on weighted average. An experimental comparison of these methods was carried out using the base of video recordings obtained in the automatic static perimetry apparatus. On these videos the ground truth tracks of pupil were marked. The comparison was conducted according to two criteria: center location error and tracking length. It is shown that only the weighted average method has an acceptable tracking length.

Primary Angle-Closure Glaucoma Due to Cyst of the Ciliary Body. Clinical Case

There is a clinical case of the occurrence of angle-closure glaucoma due to closure of the angle of front camera with the cyst of a ciliary body. Patient A., 42 years old, complained about a feeling of transient blurring of the right eye vision, visual impairment in the evening. At the initial ophthalmological examination, the maximum corrected visual acuity in both eyes was 1.0, intraocular pressure according to pneumotonometry: OD — 21 mm Hg, OS — 14.8 mm Hg. There were no changes in the anterior segment of the eyeball according to biomicroscopic data. Taking into account the asymmetry of IOP data, the patient underwent the following studies: static perimetry, optical coherence tomography (OCT), flowmetry with the calculation of tolerant intraocular pressure (TIOP). According to OCT and static perimetry, pathological deviations were not detected. When performing flowmetry on the left eye, the indicators were within normal values, however, a significant decrease in the volume of eye ocular blood flow and an increase in the IOP were determined in the right eye. In the left eye, the TIOP corresponded to the IOP, and in the right eye, the IOP indicators exceeded the TIOP value. The lack of correlation between morphofunctional indicators and flowmetry data, an unburdened hereditary history of glaucoma, and a discrepancy between flowmetry and age could indicate the development of the angle-closed glaucoma, so the patient was referred to ultrasound biomicroscopy. The echographic picture of the anterior part of the right eye was characterized by a decrease in the depth of the anterior chamber, a partial displacement of the peripheral part of the iris anteriorly, a slight narrowing of the angle of the anterior chamber, and an uneven posterior chamber. In the region of the process part of the ciliary body along the meridian of 3 hours, a thinwalled volumetric formation, anechogenic, with clear contours and dimensions was revealed: height 4.3 mm, length 4.8 mm. The root of the iris was determined by the average attachment to the ciliary body. In accordance with this, the diagnosis was made: OD — cyst of the ciliary body, the patient was referred for consultation about a possible laser surgical intervention.

Diagnostic Possibilities of Standard Automatic and FunctionSpecific Perimetry (HFA, Octopus) in the Study of the Visual Field in Patients with Compression in the Chiasm-Sellar Region

The literature review presents the results of a static perimetry for the study of the visual field in patients with compression in the chiasm-sellar region on the Humphrey Visual Field Analyzer (HFA) and Octopus. These models of perimeters are recognized as the “gold standard” and are most widely used in the global ophthalmic practice. The analysis of research results using traditional and function-specific perimetry with selective stimulation of the magnocellular and koniocellular (frequency-doubling technology perimetry, FDT; short-wavelength automated perimetry, SWAP) visual pathways was performed. The literature data analysis allows us to conclude that the static perimetry for the study of the visual field in patients with chiasmatic compression is carried out quite widely and is informative. But despite this, there are no generally accepted recommendations on the use of certain testing strategies and programs for the diagnosis and further dynamic observation of changes in the visual field in patients with this pathology. In this regard, it is advisable to conduct further studies that will allow the formation of standard perimetric protocols for diagnosing and monitoring visual field defects in patients with compression in the chiasm-sellar region based on a comparative analysis of the diagnostic informativity of various strategies and programs.