The effect of phenylephrine hydrochloride 2.5 % and sodium hyaluronate solution on visual functions and accommodation in children with myopia and its local tolerability

Purpose: to evaluate visual functions, accommodation, and local tolerance in children instilled with Phenylephrine hydrochloride 2.5 % and sodium hyaluronate solution (Stelphrin Supra). Material and methods. 30 children (60 eyes) aged 8 to 12 (ave. 10.04 ± 0.24) with low (28 eyes) and moderate (32 eyes) myopia (ave. -2.96 ± 0.17 D) were tested. Refractometry, subjective and objective accommodation, optical biometry, anterior corneal surface examination, Norn test, and polling were performed prior to one-time instillation, 30 minutes after it, and after 1 month of daily bedtime instillations of Stelphrin Supra. Results. We noted a significant decrease in the tone of accommodation in the open field by 90 % from the initial value, an approximation of the nearest point of clear vision by 27 %, an increase in the volume of absolute accommodation by 57 % and the objective amplitude of accommodation by 20 %, which indicates an increase in the accommodation ability. The pupil width increased 30 minutes after a single instillation of Stelphrin Supra, which coincided with an increase in the relative accommodation reserve by 25 % from the initial one. After a month, the pupil width significantly decreased, and the positive relative accommodation reserve decreased to a level only 12 % higher than the original one. Tear film break time significantly increased by 0.89 sec, singular spot stainings disappeared in 2 out of 6 patients, lacrimation — in 6 out of 10, pain — in 1 out of 2, blurring in 4 out of 6, feeling of “sand” — in 7 out of 9 patients who had these symptoms before instillations. Conclusion. Regular instillations of Stelphrin Supra reduce the habitual tone of accommodation, increase the accommodation ability, and improve the condition of the eye surface.

Enriched environment and visual stimuli protect the retinal pigment epithelium and photoreceptors in a mouse model of non-exudative age-related macular degeneration

Non-exudative age-related macular degeneration (NE-AMD), the main cause of blindness in people above 50 years old, lacks effective treatments at the moment. We have developed a new NE-AMD model through unilateral superior cervical ganglionectomy (SCGx), which elicits the disease main features in C57Bl/6J mice. The involvement of oxidative stress in the damage induced by NE-AMD to the retinal pigment epithelium (RPE) and outer retina has been strongly supported by evidence. We analysed the effect of enriched environment (EE) and visual stimulation (VS) in the RPE/outer retina damage within experimental NE-AMD. Exposure to EE starting 48 h post-SCGx, which had no effect on the choriocapillaris ubiquitous thickness increase, protected visual functions, prevented the thickness increase of the Bruch’s membrane, and the loss of the melanin of the RPE, number of melanosomes, and retinoid isomerohydrolase (RPE65) immunoreactivity, as well as the ultrastructural damage of the RPE and photoreceptors, exclusively circumscribed to the central temporal (but not nasal) region, induced by experimental NE-AMD. EE also prevented the increase in outer retina/RPE oxidative stress markers and decrease in mitochondrial mass at 6 weeks post-SCGx. Moreover, EE increased RPE and retinal brain-derived neurotrophic factor (BDNF) levels, particularly in Müller cells. When EE exposure was delayed (dEE), starting at 4 weeks post-SCGx, it restored visual functions, reversed the RPE melanin content and RPE65-immunoreactivity decrease. Exposing animals to VS protected visual functions and prevented the decrease in RPE melanin content and RPE65 immunoreactivity. These findings suggest that EE housing and VS could become an NE-AMD promising therapeutic strategy.

EFFECTS OF PHYSICAL STRESS ON VISUAL ACUITY IN THE PLAIN AND MOUNTAIN CONDITIONS

Научная статья посвящена установлению изменений со стороны зрительных функций у студенток старших курсов очно-заочной формы обучения в условиях гипоксической и динамической гипоксии. В период акклиматизации к гипоксической гипоксии в течение пятнадцати дней наблюдалась волнообразность или двухфазность изменения остроты зрения. Повышение с первого по пятый день и постепенное снижение с десятого по пятнадцатый день. Scientific article is devoted to establishing changes on the part of visual functions in students of senior courses of full-time education in conditions of hypoxic and dynamic hypoxia. During the period of acclimatization to hypoxic hypoxia, waviness or two-phase change in visual acuity was observed for fifteen days. Increase from day one to day five and gradual decrease from day ten to day fifteen.

Rehabilitation of visual functions in adult amblyopic patients with a virtual reality videogame: a case series

Amblyopia or lazy eye is a dysfunction of the visual system that appears during childhood and traditionally has been considered untreatable in adults. Its main consequences are the loss of visual acuity and contrast sensitivity of the amblyopic eye and binocular vision impairments. During the last years videogames have been used as a therapeutic tool for amblyopia with the inconclusive results. The present work has assessed the effectiveness of a virtual reality videogame (AmbliOK®) in the neurorehabilitation of four adult clinical cases with anisometropic amblyopia. Visual acuity, contrast sensitivity, stereopsis and interocular suppression were assessed before, during, immediately after, one month and one year (in one patient) after the training. The intervention was conducted along four weeks (10 h) and yielded the variable results. In general, all patients showed an improvement in visual functions although not all ameliorated in the same way. Visual acuity measures improved in all patients, falling outside the amblyopia criterion at the end of the treatment. However, the improvement was not maintained one month later in two patients. Contrast sensitivity progressively improved for the amblyopic and the fellow eyes with all patients showing better results one month after the treatment. The patient assessed one year after still showed better results than in the baseline. Patients showing bad stereopsis in the baseline reached a performance considered normal one month and even one year after the treatment. The effectiveness of the treatment seems to be related to the characteristics of patients.

Nystagmus: prevalence, classification, pathogenesis. (Literature review)

The article provides information on the prevalence of nystagmus in the Russian Federation and the world. However, the lack of standards for data collection and the very understanding of the definition of optical nystagmus is the reason for the variation in prevalence values in different sources. Additionally, the article presents various classifications of nystagmus. Currently, there are many different classifications, and the most commonly used examples are given. The classification of eye movement disorders and strabismus, adopted by the working group in 2001 (Classification of Eye Movement Abnormalities and Strabismus CEMAS), is used worldwide. In our country, the most popular was the classification proposed by E.S. Avetisov (2001). Various sources have suggested quite contradictory data on the nature of the onset and the mechanism of development of nystagmus. Recently, the issues related to the pathogenesis of nystagmus have been revised. The theories that existed at the end of the last century were not substantiated in modern works. The pathogenesis of optic nystagmus remains less studied due to its complexity and ambiguity. The investigations continue to find the relationship between the pathology of the central nervous system and functional disorders of visual functions. The question of the relationship between visual acuity and nystagmus remains unclear. Does a decrease in vision cause nystagmus? How do oscillatory movements in nystagmus affect visual functions? This article encompasses the main areas of this issue. However, despite a significant step in understanding the causes of the development of nystagmus, this pathology remains insufficiently studied. This prompts many researchers and practicing doctors to study its pathogenesis further

Complex use of energetic surgery in treatment of patients with primary open-angle glaucoma and cataract on the background of pseudoexfoliative syndrome

BACKGROUND: Glaucoma remains one of the current problems of modern ophthalmology. The combination of glaucoma and cataract is observed in 1738.6% of cases, and glaucoma with pseudoexfoliative syndrome in 2050% of primary open-angle glaucoma cases. AIM: The aim of this work is to develop an effective and safe technology of complex energetic surgical treatment of the incipient primary open-angle glaucoma stage and cataract on the background of pseudoexfoliation syndrome on the basis of modified laser, hydrodynamic and ultrasound methods use. MATERIALS AND METHODS: 187 patients (187 eyes) with the incipient stage of primary open-angle glaucoma, cataract and pseudoexfoliation syndrome were examined. In the main group (111 eyes), selective laser trabeculoplasty followed by femtosecond laser-assisted cataract surgery with hydrodynamic trabeculocleaning was performed. Patients in the control group (76 eyes), after selective laser trabeculoplasty, underwent phacoemulsification according to the standard technique. RESULTS: The developed technology allowed to reach the hypotensive effect in 35.2% (t=23.0; р 0.001) of baseline intraocular pressure values, of individual intraocular pressure level without adding IOP-lowering medications in 27% of cases, stabilization of visual functions and morphometric indices of the optic disc during 2 years of follow-up in 97.3% of cases unlike the selective laser trabeculoplasty with subsequent phacoemulsification (21.2, 5.3 and 81.6% respectively). The patients of the main group had significantly lower energy expenditure during the stage of phacoemulsification, a lower percentage of postoperative inflammatory reaction was noted, and a persistent hypotensive effect with stabilization of visual functions was achieved based on the results of a two-year follow-up. CONCLUSIONS: Femtosecond laser-assisted phacoemulsification, performed as part of complex treatment in patients with cataract and incipient stage of primary open-angle glaucoma, is a sparing method that minimizes surgical trauma and achieves a persistent hypotensive effect, reduces intraocular pressure to an individual level and stabilizes visual functions in 97.3% of cases.

The Impact of Clinical Atropine Use in Taiwanese Schoolchildren: Changes in Physiological Characteristics and Visual Functions

Taiwan is commonly noted for its high prevalence of myopia, as well as a long history of more than 20 years of using atropine to control myopia. However, the clinical implications are rarely discussed. This is a cross-sectional study investigating the influence of topical atropine instillation on ocular physiology, visual function, and visual discomfort in children. Aged 7 to 12 years, 212 schoolchildren were recruited and divided into the atropine group and the non-atropine group. Physiological characteristics such as pupil size and intraocular pressure were measured, and a variety of visual functions was also evaluated. A questionnaire was used to investigate the side effects and visual complaints caused by atropine treatment. There was a significant difference in pupil size (OD: 5.40 ± 0.90 vs. 6.60 ± 1.01 mm; OS: 5.42 ± 0.87 vs. 6.64 ± 1.00 mm, p < 0.001) between the two groups. Reductions in near visual acuity, accommodation, convergence ability, and stereopsis were observed in the atropine group. The horizontal pupil diameter enlarged, and visual functions were greatly affected after administration of topical atropine. The changes in visual function during atropine therapy need to be carefully monitored by clinicians, while patient compliance is usually the key to success.

Spared perilesional V1 activity underlies training-induced recovery of luminance detection sensitivity in cortically-blind patients

Damage to the primary visual cortex (V1) causes homonymous visual-field loss long considered intractable. Multiple studies now show that perceptual training can restore visual functions in chronic cortically-induced blindness (CB). A popular hypothesis is that training can harness residual visual functions by recruiting intact extrageniculostriate pathways. Training may also induce plastic changes within spared regions of the damaged V1. Here, we link changes in luminance detection sensitivity with retinotopic fMRI activity before and after visual discrimination training in eleven patients with chronic, stroke-induced CB. We show that spared V1 activity representing perimetrically-blind locations prior to training predicts the amount of training-induced recovery of luminance detection sensitivity. Additionally, training results in an enlargement of population receptive fields in perilesional V1, which increases blind-field coverage and may support further recovery with subsequent training. These findings uncover fundamental changes in perilesional V1 cortex underlying training-induced restoration of conscious luminance detection sensitivity in CB.