Scleral lenses, corneal collagen crosslinking, corneal implants and deep anterior keratoplasty are used to correct deforming changes in the cornea at advanced stages of keratoconus, which improves the quality of vision (QoV). The article presents an analysis of changes in QoV in a 30-year-old patient with stage III keratoconus who underwent intracorneal implantation of an allograft with a width of 2.75 mm and thickness of 300 µm at a depth of 370 µm. The following parameters were measured before and 6 months after the procedure: uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), VA with glare, higher order aberrations (HOA), thickness of the lipid layer of the tear film, spatial contrast sensitivity, visual productivity. Observation results show that the Kmax index decreased from 55.9 D to 48.0 D, Kmin - from 39.8 D to 39.4 D, UCVA increased from 0.1 to 0.8 and BCVA - from 0.35 to 0.8. Thickness of the lipid layer of the tear film remained the same. The glare effect with different degrees of brightness did not affect visual acuity. Spatial contrast sensitivity in photopic conditions at medium frequencies increased from 19 to 37 dB, at high frequencies from - 0.5 to 22.5 dB, in mesopic conditions at medium frequencies from 11 to 28 dB, at high frequencies from - 0.5 to 12 dB. The «coma» and «spherical» aberrations decreased by 2 and 3 times, respectively, while «trefoil» increased by 3 times. Visual productivity increased by 36.8%. It may be concluded that the use of a wide intrastromal allograft in keratoconus improves the patient\'s visual quality and visual productivity. At the same time, the «vignetting» effect from the graft side is negligible in photopic conditions and is significant in mesopic conditions.
Для коррекции деформирующих изменений роговицы при выраженных стадиях кератоконуса (КК) применяют склеральные линзы, кросслинкинг роговичного коллагена, корнеальные имплантаты и глубокую переднюю послойную кератопластику, что улучшает качество зрения (КЗ). Представлена оценка изменения КЗ пациента 30 лет с КК III стадии, которому была произведена интракорнеальная имплантация широкого аллотрансплантата шириной 2,75 мм, толщиной 300 мкм на глубине 370 мкм. До и через 6 мес после операции измеряли остроту зрения (ОЗ) без коррекции и с коррекцией, ОЗ с глэр, аберрации высшего порядка, толщину липидного слоя слезной пленки, пространственную контрастную чувствительность, зрительную продуктивность. По результатам наблюдения, показатель Kmax снизился с 55,9 до 48,0 дптр, Kmin — с 39,8 до 39,4 дптр, ОЗ без коррекции возросла с 0,1 до 0,8, с коррекцией — с 0,35 до 0,8. Толщина липидного слоя слезной пленки осталась прежней. Глэр-эффект с разной степенью яркости не оказывал влияния на ОЗ. Пространственная контрастная чувствительность в фотопических условиях возросла на средних частотах с 19 до 37 дБ, на высоких — с (–)0,5 до 22,5 дБ, в мезопических условиях на средних частотах — с 11 до 28 дБ, на высоких — с (–)0,5 до 12 дБ. Аберрации «coma» и «sferical» снизились в 2 и 3 раза соответственно, «trefoil» увеличился в 3 раза. Зрительная продуктивность возросла на 36,8%. Таким образом, можно сделать вывод, что использование широкого интрастромального аллотрансплантата при КК повышает КЗ пациента и его зрительную работоспособность. При этом влияние эффекта виньетирования (затемнения) со стороны трансплантата ничтожно в фотопических условиях и имеет значение в мезопических условиях.

UNASSIGNED: To investigate whether short-term exposure to high temporal frequency full-field flicker has an impact on spatial visual acuity in individuals with varying degrees of myopia.
UNASSIGNED: Thirty subjects (evenly divided between control and experimental groups) underwent a 5-min exposure to full-field flicker. The flicker rate was lower than critical flicker frequency (CFF) for the experimental group (12.5 Hz) and significantly higher than CFF for the controls (60 Hz). Spatial contrast sensitivity function (CSF) was measured before and immediately after flicker exposure. We examined whether the post flicker CSF parameters were different from the pre-exposure CSF values in either of the subject groups. Additionally, we examined the relationship between the amount of CSF change from pre to post timepoints and the degree of subjects\' myopia. The CSF parameters included peak frequency, peak sensitivity, bandwidth, truncation, and area under log CSF (AULCSF).
UNASSIGNED: There was no significant difference of all five pre-exposure CSF parameters between the two groups at baseline (P = 0.333 ∼ 0.424). Experimental group subjects exhibited significant (P < 0.005) increases in peak sensitivity and AULCSF, when comparing post-exposure results to pre-exposure ones. Controls showed no such enhancements. Furthermore, the extent of these changes in the experimental group was correlated significantly with the participants\' refractive error (P = 0.005 and 0.018, respectively).
UNASSIGNED: Our data suggest that exposure to perceivable high-frequency flicker (but, not to supra-CFF frequencies) enhances important aspects of spatial contrast sensitivity, and these enhancements are correlated to the degree of myopia. This finding has implications for potential interventions for cases of modest myopia.

Early visual deprivation is known to have profound consequences on the subsequent development of spatial visual processing. However, its impact on temporal processing is not well characterized. We have examined spatial and temporal contrast sensitivity functions following treatment for early and extended bilateral visual deprivation in fifteen children born with congenital cataracts in rural India. The results reveal a marked difference in post-treatment spatial and temporal sensitivities. Whereas spatial processing in newly sighted children is significantly impaired relative to age-matched controls, temporal processing exhibits remarkable resilience and is comparable to that in the control group. This difference in spatial and temporal outcomes is especially surprising given our computational analyses of video sequences which indicate a strong linkage between the spatial and temporal spectral content of natural visual inputs. We consider possible explanations for this discrepancy.

OBJECTIVE: To study the data of monocular and binocular multifocal electroretinogram (mfERG), flash visual evoked potential (f-VEP), spatial contrast sensitivity (SCS) with and without yellow filters in healthy elderly people.
METHODS: The study included 16 people (8 male and 8 female) with average age of 51.63±4.7 years. Their visual acuity was 0.5±0.35 without correction and 1.0 with correction. For spectral correction, we used Y1 color filters (CF) (analogue of SN60AT) from the «Lornet-M vision spectral correction kit» set with 80% light transmission and wave cut-off of 460 nm. Patients had mfERG recordings performed monocularly and binocularly, f-VEP monocularly, and their spatial contrast sensitivity (SCS) was measured (Astroinform SPE, Russia). The data acquired before and after applying CF was compared.
RESULTS: The data of SCS with light filter was slightly higher at medium and high spatial frequencies (SF): for the right eye on medium SF of 43.8 and 41.8 dB (p≤0.735), 41.5 and 39.8 dB (p≤0.061) for the left eye. The increase of mfERG P1 latency monocularly after application of CF in the R1 ring area was 3.0 ms (40.8-43.8ms) for the right eye (p≤0.05) and 0.9 ms for the left eye (43.7-44.5ms) (p≤0.326). The trend remained for simultaneous mfERG.
CONCLUSIONS: The influence of yellow filters on spectral vision correction can be manifested in inconsistency of SCS, f-VEP, monocular and binocular mfERG readings. Statistically significant differences in healthy individuals of 5th-6th age decades manifest as elongation of the latency of mfERG peaks.
UNASSIGNED: Изучить показатели монокулярной и бинокулярной мультифокальной электроретинографии (мф-ЭРГ), вызванных зрительных корковых потенциалов на вспышку (в-ЗВКП) и пространственную контрастную чувствительность (ПКЧ) при использовании желтых светофильтров (СФ) у здоровых лиц пожилого возраста.
UNASSIGNED: Было обследовано 16 человек (8 мужчин и 8 женщин), средний возраст обследуемых составил 51,63±4,7 года. Острота зрения без коррекции — 0,5±0,35, с коррекцией — 1,0. Для спектральной коррекции использовались СФ Ж1 (аналог SN60AT) из «Набора для спектральной коррекции зрения» (Лорнет-М, Россия) с 80% пропусканием света и длиной волны отсечения 460 нм. Регистрировали мф-ЭРГ монокулярно и бинокулярно, в-ЗВКП монокулярно, исследовали ПКЧ (ООО «Астроинформ СПЕ», Россия). Сравнивали данные до и после применения СФ.
UNASSIGNED: Показатели ПКЧ со СФ были несколько выше на средних и высоких пространственных частотах (ПЧ): 43,8 и 41,8 Дб для правого глаза на средних ПЧ (p≤0,735), 41,5 и 39,8 Дб для левого глаза (p≤0,061). Увеличение Lp1 (латентности компонента P1) мф-ЭРГ после применения СФ в зоне кольца К1 составило при монокулярном измерении 3,0 ms (40,8—43,8 ms) для правого глаза (p≤0,05) и 0,9 ms (43,7—44,5 ms) — для левого (p≤0,326). При симультанной мф-ЭРГ тенденция сохранялась.
UNASSIGNED: Влияние желтых СФ при спектральной коррекции зрения может проявляться неустойчивостью показателей ПКЧ, в-ЗВКП, монокулярной и бинокулярной мф-ЭРГ. Статистически значимые отличия у здоровых лиц пятой-шестой возрастной декады проявляются в виде удлинения латентности пиков мф-ЭРГ.

Up to now, there has not been a comparison of spatial contrast sensitivity (SCS) in patients with primary and pseudoexfoliation open-angle glaucoma (POAG; PEG) and ophthalmic hypertension (OH).
OBJECTIVE: To study the characteristics of SCS in patients with POAG, PEG (as well as in the paired eye without glaucoma) and OH.
METHODS: The work was performed in the period from 2011 to July 2017. Analytical, observational case-control study data was analyzed. The study included 1380 patients under dynamic observation; in accordance with inclusion and non-inclusion criteria, 290 patients (540 eyes) with POAG, PEG, OH, as well as healthy people were included in the study. SCS was measured using \'Zebra v 3.0\' software developed by the laboratory of clinical physiology of vision named after S.V. Kravkova in collaboration with \'Astroinform SPE\' LLC. Patients were shown vertical achromatic (black and white) and colored (red, green, and blue) gratings of specific spatial frequencies (0.5; 1; 2; 4; 8; 16 cycles/degree). Among the patients of the study, 243 (83%) were female and 47 (17%) were male. The average age of all patients at the time of inclusion in the study was 67.75 (62.8; 74.5); 67.84±8.7 years.
RESULTS: The study revealed an increase of SCS in patients with OH and their tendency for a slight increase in the contralateral eye with unilateral PEG in comparison with measurements taken from patients of POAG and PEG groups.
CONCLUSIONS: The revealed increase of SCS is likely to be a consequence of increased or preserved hemodynamic characteristics in the vessels of the eye and orbit in patients with hypertension and in the contralateral eye in unilateral glaucoma, as described in our previous publications. At the same time, generalized changes in the vascular wall in patients with \'PEG-\' on the paired eye only predetermine a tendency for an increase of SCS indices.
До настоящего времени не проводилось сравнения пространственной контрастной чувствительности (ПКЧ) у пациентов с первичной и псевдоэксфолиативной открытоугольной глаукомой (ПОУГ, ПЭГ) и офтальмогипертензией (ОГ). Цель - изучить особенности ПКЧ у пациентов с ПОУГ, ПЭГ (и на парном глазу без глаукомы) и ОГ. Материал и методы. Работа выполнена в период с 2011 г. по июль 2017 г. Проанализированы данные аналитического, наблюдательного исследования случай-контроль. Под динамическим наблюдением находились 1370 пациентов, в соответствии с критериями включения и невключения объектом исследования стали 290 пациентов (540 глаз) с ПОУГ, ПЭГ, ОГ и здоровые люди. Проведено исследование ПКЧ с использованием программы \'Зебра v 3.0\', разработанной лабораторией клинической физиологии зрения им. С.В. Кравкова совместно с ООО \'Астроинформ СПЕ\'. Пациентам предъявлялись вертикальные ахроматические (черно-белые) и цветные (красного, зеленого и синего цвета) решетки определенной пространственной частоты (0,5; 1; 2; 4; 8; 16 цикл/град). Среди обследованных пациентов было 243 (83٪) женщины и 47(17٪) мужчин. Средний возраст всех пациентов на момент включения в исследование составил 67,75 (62,8; 74,5); 67,84±8,7года. Результаты. Выявлено повышение показателей ПКЧ у пациентов с ОГ и их тенденцию к некоторому увеличению на контрлатеральном глазу с односторонней ПЭГ в сравнении с показателями пациентов групп ПОУГ и ПЭГ. Заключение. Вероятно, выявленное увеличение ПКЧ можно трактовать как следствие повышенных или сохранных гемодинамических характеристик в сосудах глаза и орбиты при ОГ и на контрлатеральном глазу при односторонней глаукоме, что описано в предыдущих наших публикациях. Вместе с тем генерализованные изменения сосудистой стенки у пациентов с \'ПЭГ-\' на парном глазу предопределяют только тенденцию к повышению показателей ПКЧ.

The study was undertaken to examine visual pathway function by psycho- and electrophysiological studies in patients with type 1 diabetes. Sixty-three patients (age 25±2.3 years) with moderate type 1 diabetes in a subcompensated state (mean HbA1c 7.4±0.2%), including 32 patients without diabetic retinopathy (DR) and 31 patients with nonproliferative diabetic retinopathy were examined. A control group consisted of 30 healthy individuals. The complex of diagnosis included critical flicker frequency test, retinal light and contrast sensitivity threshold tests, electroretmography (ERG), and studies of optic nerve lability and visual evoked potentials (VEP). A comprehensive study established functional visual pathway abnormalities that were undetectable on routine ophthalmologlcal examination. Lower ERG \"a\" wave amplitudes, higher latency, and reductions in the amplitude of VEP P100 peak and in spatial contrast sensitivity for low frequencies were of the greatest value in the diagnosis of diabetic abnormalities of the visual pathway. Visual pathway lesions are detectable in patients with type 1 diabetes without DR. In the latter, these lesions are more pronounced.
Цель - изучить функциональное состояние проводящего отдела зрительного анализатора с использованием психо- и электрофизиологических методов у больных сахарным диабетом (СД) 1-го типа. Обследовано 63 пациента в возрасте 25 ± 2,3 года с СД 1-го типа средней степени тяжести в состоянии субкомпенсации (HbA1с 7,4 ± 0,2%), в том числе 32 больных без диабетической ретинопатии (ДР) и 31 больной с непролиферативной ДР. Контрольная группа - 30 здоровых лиц. Комплекс диагностики включал определение критической частоты слияния мельканий (КЧСМ), порога электрической чувствительности (ПЭЧ) сетчатки, лабильности зрительного нерва (ЗН), электроретинографию (ЭРГ), визоконтрастометрию (ВКМ), исследование зрительных вызванных потенциалов (ЗВП). При комплексном обследовании установлены нарушения функции проводящих путей зрительного анализатора, которые не выявляются при обычном офтальмологическом исследовании. Наиболее значимыми для диагностики диабетических нарушений зрительного анализатора являются: снижение амплитуды а-волны при ЭРГ, увеличение латентности и снижение амплитуды пика Р100 ЗВП, снижение пространственной контрастной чувствительности в области низких частот. Поражения проводящих путей зрительного анализатора выявлены у больных СД 1-го типа без ДР, при ДР они более выражены.

We examined how visual sensitivity and perception are affected by adaptation to the characteristic amplitude spectra of X-ray mammography images. Because of the transmissive nature of X-ray photons, these images have relatively more low-frequency variability than natural images, a difference that is captured by a steeper slope of the amplitude spectrum (~ - 1.5) compared to the ~ 1/f (slope of - 1) spectra common to natural scenes. Radiologists inspecting these images are therefore exposed to a different balance of spectral components, and we measured how this exposure might alter spatial vision. Observers (who were not radiologists) were adapted to images of normal mammograms or the same images sharpened by filtering the amplitude spectra to shallower slopes. Prior adaptation to the original mammograms significantly biased judgments of image focus relative to the sharpened images, demonstrating that the images are sufficient to induce substantial after-effects. The adaptation also induced strong losses in threshold contrast sensitivity that were selective for lower spatial frequencies, though these losses were very similar to the threshold changes induced by the sharpened images. Visual search for targets (Gaussian blobs) added to the images was also not differentially affected by adaptation to the original or sharper images. These results complement our previous studies examining how observers adapt to the textural properties or phase spectra of mammograms. Like the phase spectrum, adaptation to the amplitude spectrum of mammograms alters spatial sensitivity and visual judgments about the images. However, unlike the phase spectrum, adaptation to the amplitude spectra did not confer a selective performance advantage relative to more natural spectra.

Leber inherited optic neuropathy (LHON) is characterized by subacute bilateral loss of central vision due to dysfunction and loss of retinal ganglion cells (RGCs). Comprehensive visual electrophysiological investigations (including pattern reversal visual evoked potentials, pattern electroretinography and the photopic negative response) performed on 13 patients with acute and chronic LHON indicate early impairment of RGC cell body function and severe axonal dysfunction. Temporal, spatial and chromatic psychophysical tests performed on 7 patients with acute LHON and 4 patients with chronic LHON suggest severe involvement or loss of the midget, parasol and bistratified RGCs associated with all three principal visual pathways.

Research on aging and vision has increased dramatically over the past few decades. Changes in our visual capacities in later adulthood have the potential to impact our ability to perform common everyday visual tasks such as recognizing objects, reading, engaging in mobility activities, and driving, thus influencing the quality of our life and well-being. Here, we discuss several common visual problems in older adults that cause performance problems in the visual tasks of everyday living and when exacerbated are related to the development of common eye conditions and diseases of aging.

Birds are generally thought to have excellent vision with high spatial resolution. However, spatial contrast sensitivity of birds for stationary targets is low compared to other animals with similar acuity, such as mammals. For fast flying animals body stability and coordination are highly important, and visual motion cues are known to be relevant for flight control. We have tested five budgerigars (Melopsittacus undulatus) in behavioural discrimination experiments to determine whether or not stimulus motion improves contrast sensitivity. The birds were trained to distinguish between a homogenous grey field and sine-wave gratings of spatial frequencies between 0.48 and 6.5 cyc/deg, and Michelson contrasts between 0.7% and 99%. The gratings were either stationary or drifting with velocities between 0.9 and 13 deg/s. Budgerigars were able to discriminate patterns of lower contrast from grey when the gratings were drifting, and the improvement in sensitivity was strongest at lower spatial frequencies and higher drift velocities. Our findings indicate that motion cues can have positive effects on visual perception of birds. This is similar to earlier results on human vision. Contrast sensitivity, tested solely with stationary stimuli, underestimates the sensory capacity of budgerigars flying through their natural environments.