ABSTRACT
A brand-new class of photoreceptors has been identified in the past 20a: intrinsically photosensitive retinal ganglion cells(ipRGC). With melanopsin as its photopigment, ipRGCs transmit light signals to non-imaging brain regions like the suprachiasmatic nucleus(SCN)and the olivary pretectal nucleus(OPN)to regulate circadian photoentrainment and pupillary light reflex; a small portion of the signals are projected to brain imaging regions like the dorsal lateral geniculate nucleus(dLGN)and superior colliculus(SC), to participate in imaging vision. There are six different ipRGC subtypes(M1～M6), each with its own morphological and physiological characteristics. In addition to receiving signaling inputs from the rods and cones, ipRGCs also regulate retinal signals through chemical and electrical synapses and play important roles in visual signaling and visual development. It has been discovered that ipRGCs are implicated in several systemic and ocular illnesses. Overall, various aspects of ipRGC are reviewed including the discovery, general physiological properties, signaling, and the relationship with disease in this work.
ABSTRACT
ABSTRACT BACKGROUND: This article systematically updates the literature on changes in visual functions during the phases of the normal menstrual cycle in women. OBJECTIVES: To update Guttridge's 1994 review of visual structures and functions associated with the menstrual cycle and broaden the search through psychophysical, neuroimaging and neurobehavioral measurements covering 1994-2020. DESIGN AND SETTING: Narrative review conducted in a neurosciences and behavior laboratory in Brazil. METHODS: The PubMed, Cochrane Clinical Answers and Google Scholar databases were searched. After screening and applying the eligibility criteria, 32 articles were examined. Through this analysis, the following information was extracted: (1) geographical distribution of the study; (2) sample size (according to age and phase of the menstrual cycle); (3) type of measurements according to psychophysical, neuroimaging and neurobehavioral instruments; (4) vision testing model; (5) visual subcategory evaluated; (6) categories of processed visual stimuli; and (7) main findings. RESULTS: The menstrual phases give rise to significant changes in visual functions, including in relation to orientation and spatial attention, visual campimetry and visual sensitivity. These relate specifically to the follicular and luteal phases. CONCLUSIONS: These findings theoretically expand the effects of menstrual cycles on visual functions found by Guttridge (1994). Despite some inconsistencies in the studies analyzed, it was found that visual processing during the follicular and luteal phases of the normal menstrual cycle of healthy women can explain physiological, cognitive, behavioral and social modulations.
Subject(s)
Humans , Female , Follicular Phase , Menstrual Cycle , Brazil , Luteal PhaseABSTRACT
@#AIM: To explore whether low myopia would affect cerebral visual functions by comparing perceptual eye position(PEP), fixation stability and stereoacuity tests between low myopic and normal adolescents. <p>METHODS: Totally 120 adolescents matched in age and gender participated in our study. Subjects were divided into three groups according to their refractive states. The cerebral visual functions tested in our study included perceptual eye position(PEP), fixation stability and stereoacuity. Stereoacuity tests involved in our study could be categorized into two parts. The first part was classical stereo tests including Titmus and synoptophore stereo test. The second part was 3D random-dot test for zero-order stereoacuity(hereinafter as zero-order test)at different viewing distances(0.8 m and 1.5 m).<p>RESULTS:1)PEP: the deviation of horizontal PEP was significantly larger in non-anisometropia when compared to control group. Both horizontal and vertical PEP bias pixels were significantly larger in anisometropia group. 2)χ2 test showed that both non-anisometropia group and anisometropia group had more trouble in holding their fixation stable. Moreover, anisometropia group had more abnormal results than other two groups. And in zero-order test at 1.5 m, both non-anisometropia and anisometropia had more abnormal results in stereoacuity than control group. The correlation between fixation stability and near stereoacuity(Titmus and zero-order stereoacuity at 0.8 m)was weak and positive.<p>CONCLUSION:Low myopic adolescents still have certain defects in cerebral visual functions; Examinations used in our study were useful in assessing cerebral visual functions. They could provide better follow-up evaluation and solid ground for further specific treatments in treating defects of cerebral visual functions. So far, local retinal environment has been the focus on the development in myopia. Our results suggested that researchers might pay more attention on visual cortex in studying the mechanisms of myopia in the near future.
ABSTRACT
@#AIM: To investigate the effect of cardiovascular risk factors on the occurrence of nonarteritic anterior ischemic optic neuropathy(NAION)and visual functions of the patients.<p>METHODS: Sixty-eight patients diagnosed as initial ipsilateral NAION(68 eyes)in NAION group and another 68 patients(68 eyes)matched in age, gender and systemic diseases in Control group were selected from June 2014 to June 2016 were enrolled in this study and evaluated for their levels of homocysteine(Hcy), blood lipids, folic acid and vitamin B12, as well as carotid Doppler ultrasonography. The visual functions were also examined in patients with NAION.<p>RESULTS: The levels of Hcy(24.8±13.9μmol/L), total plasma cholesterol(4.5±1.0mmol/L), triglyceride(2.0±0.9 mmol/L)and low-density lipoprotein(2.9±0.8mmol/L)in NAION patients were significantly higher(<i>P</i><0.05)than those in Control group(11.1±8.2μmol/L, 3.8±0.7mmol/L, 1.5±0.5mmol/L and 2.3±0.5mmol/L)while the level of vitamin B12 decreased significantly(315.6 ±214.5pg/mL, <i>P</i><0.05)in NAION group in comparison with those(467.9±198.2pg/mL)in Control group. However, no significant differences in the artery resistance and inner diameter of the internal carotid were detected between the two groups. The mean deviation(MD)of the visual field was 16.6±7.5dB in NAION group. The levels of Hcy, vitamin B12, folic acid and blood lipid and the presence of systemic diseases were not the risk factors for the visual field damage in NAION patients. MD value was associated with the amplitude and peak latency of P100 waves.<p>CONCLUSION: Hyperhomocysteinemia, hyperlipidemia and low vitamin B12 are the risk factors of in NAION patients. These risk factors, however, are not related to the extent of visual field damage. To some extent, the amplitude and peak latency of visual evoked potentials can reflect the extent of visual field damage.
ABSTRACT
@#The aim of the present study was to evaluate visual functions and retinal morphology of Polypoidal Choroidal Vasculopathy (PCV) patients seen in an AMD referral centre of Malaysia and to further explore association between visual functions and optical coherence tomography (OCT) parameters in PCV eyes. In this single centre, cross sectional study, best corrected distance visual acuity (DVA), near vision acuity (NVA), reading speed (RS), and contrast sensitivity (CS) were measured in naïve PCV eyes. Selective parameters such as integrity of external limiting membrane (ELM), inner segment and outer segment junction (IS-OS), retinal pigment epithelium and Bruch’s membrane (RPE-BM) complex, average retinal thickness (ART) and volume (ARV), central retinal thickness (CT), centre maximum (CTmax) and centre minimum (CTmin) thickness were assessed using spectral-domain OCT. Forty-three new PCV eyes of 42 patients were evaluated. Mean (±SD) DVA, NVA, CS, RS were 0.83 ± 0.35 logMAR, 0.77 ± 0.3 logMAR, 0.69 ±.26 log CS and 59.56 ±14 words per minutes respectively. ART and CT showed good correlation with DVA (r=0.571& 0.546) and CS (r= 0.576 & 0.586). ARV and CTmax showed good correlation with CS (r=0.516 &, 0.513). The mean DVA, NVA and CS between three ELM and IS-OS status were significantly different (p=.002 & .000; p=.012 & .029; p=.005 & .001). In conclusion, present study reports visual functions and OCT characteristics of PCV patients in an AMD referral centre of Malaysia. Many of the quantitative and qualitative OCT parameters showed good association with the visual functions in eyes with PCV.
Subject(s)
Polypoidal Choroidal VasculopathyABSTRACT
Context: Retinal nerve fiber layer (RNFL) thinning has been demonstrated in cases of optic neuritis (ON) and multiple sclerosis (MS) in Caucasian eyes, but no definite RNFL loss pattern or association with visual functions is known in Indian eyes. Aim: To evaluate RNFL thickness in cases of ON and MS, and to correlate it with visual function changes in Indian patients. Settings and Design: Cross‑sectional case‑control study at a tertiary level institution. Materials and Methods: Cases consisted of patients of (i) typical ON without a recent episode (n = 30:39 ON eyes and 21 fellow eyes), (ii) MS without ON (n = 15;30 eyes) while the controls were age‑matched (n = 15; 30 eyes). RNFL thickness was measured using the Stratus 3°CT. The visual functions tested included the best‑corrected visual acuity (BCVA), contrast sensitivity, stereopsis, visual evoked responses, and visual fields. Statistical analysis used: Intergroup analysis was done using ANOVA and Pearson’s correlation coefficient used for associations. Results: RNFL thickness was reduced significantly in the ON and MS patients compared to the controls (P‑0.001). Maximum loss is in the temporal quadrant. Lower visual function scores are associated with reduced average overall RNFL thickness. In ON group, RNFL thinning is associated with severe visual field defects while contrast sensitivity has strongest correlation with RNFL in the MS group. Conclusions: RNFL thickness is reduced in ON and MS cases in a pattern similar to Caucasians and is associated with the magnitude of impairment of other visual parameters. Contrast sensitivity and stereoacuity are useful tests to identify subclinical optic nerve involvement in multiple sclerosis.
ABSTRACT
Effects of a dietary supplement of carp gallbladder powders, New-Eyereturn<sup>®</sup>, on visual functions were investigated in elder ophthalmic patients. The tablets (12 tablets/day) were taken by 15 and 12 subjects for one-month and three-month period, respectively. In comparison with the visual function data at baseline and thereafter, improvements of subjective symptoms by questionnaire was observed in a three-month intake group, although no significant difference of the values of visual acuity and intraocular pressure was recognized. These results suggest intake of this dietary supplement has a possibility to improve visual functions of elder people.<br>
ABSTRACT
The purpose of this study was to investigate the status of contact lens use in the pool for water polo players. A total of 627 male subjects were studied : junior high school players (n=190), high school players (n=188), college players (n=121) and water polo club players (n=128).Results were summarized as follows : 1) The percentage of players using vision correction devices in daily life was 43.38%, and use of contact lenses during water polo play was 30.14% for all subjects. 2) Junior high school players using contact lenses during water polo play showed a significantly lower rate compared with other players (<i>X</i><sup>2</sup>=34.38, p<.01). 3) There were a lot of users of disposable type contact lenses during water polo play. 4) Players using contact lenses during water polo play had significantly higher corneal and conjunctival damage than subjects using vision correction devices in daily life and subjects without vision correction devices (<i>X</i><sup>2</sup>=13.64, p<.01).We concluded that it was a problem for junior high school players with low vision acuity during water polo play.