Fundamentals of Presbyopia: visual processing and binocularity in its transformation

Abstract

BackgroundThe accommodation has considerable interactions with the pupil response, vergence response and binocularity. The transformation of visual reception processing and the changes of the binocular cooperation during the presbyopia development are still poorly studied. So, the regularities of visual system violation in the presbyopia formation need to be characterized. This study aims to reveal the transformation of visual reception processing and to determine the role of disturbances in binocular interactions in presbyopia formation.MethodsThis study included 60 people with emmetropic refraction, uncorrected distance visual acuity 1.0 or higher (decimal scale), normal color perception, without concomitant ophthalmopathology. The first group consisted of 30 people (from 18 to 27 years old) without presbyopia, the second cohort comprised 30 patients (from 45 to 55 years old) with presbyopia. The eyeball anatomy and optics were evaluated using ultrasound biomicroscopy, aberrometry, and pupillometry. The functional state of the visual system was investigated under monocular and binocular conditions. The registration of the disparate fusional reflex limits was performed by the original technic using a diploptic device which facilitated investigation of the binocular interaction under natural conditions without the accommodation response, but with the different vergence load. The disparate fusional reflex was analyzed using the proximal and distal fusion borders, and the convergence and divergence fusion borders. The calculation of the area of binocularity field was performed in cm2.ResultsThe presbyopia formation is characterized by a change in an intraocular anatomy, optics, visual processing, and binocularity. The processes of binocular interaction inhibition make a significant contribution to the misalignment of the visual perception. The modification of the proximal, distal and convergence fusion borders was determined. It was revealed that 87% of the presbyopic patients had binocularity shortage, whereas the reduction of binocularity field area in extreme grade was seen in 6% of cases.ConclusionsThe presbyopia formation is accompanied by a significant reorganization of the visual system activity and by the creation of the new visual processing interactions. These data may be useful in presbyopia surgery.

Computer vision syndrome in healthcare workers using video display terminals: an exploration of the risk factors

“…The questionnaire on anamnesis, occupational information, and history of exposure to VTD was developed to collect information about the sociodemographic variables (sex and age), ocular history (ophthalmic or contact lens use, previous eye diseases, ocular treatment, and/or ocular surgeries), job characteristics (hospital, occupational groups, work schedules, and seniority), history of exposure to VDTs at work (hours per day of use), opinions about the ease of use of the software applications, and exposure to VDTs outside of work. Age was categorized as ≤35, 36–45, and >45 years, since each of these groups have different accommodative conditions (Girum et al, 2017; Rozanova et al, 2018). Seniority was categorized as ≤10, 10–20, and >20 years because these cut‐off points divided the sample into three groups of similar sizes.…”

“…Age was categorized as ≤35, 36-45, and >45 years, since each of these groups have different accommodative conditions (Girum et al, 2017;Rozanova et al, 2018). Seniority was categorized as ≤10, 10-20, and >20 years because these cut-off points divided the sample into three groups of similar sizes.…”

Binocular Interaction Measurement in Non-Strabismus Patients

“…Rabichev (1998) showed that the virtual binocular image obtained with a binarimeter is a measure of binocular interaction. Later, the method of spatial reconstruction of the area of binocular interaction (ABI), which enables calculation of the area of fusional field, was proposed [21,22], but the normative database of ABI under free haploscopy in non-strabismus patients is absent.…”