SYSTEM FOR MEASURING RODENTS' VISUAL FUNCTION: DESIGN AND IMPLEMENTATION

2014 ◽  
Vol 26 (02) ◽  
pp. 1450018 ◽  
Author(s):  
Carlos Perez-Vidal ◽  
Alejandro Garcia ◽  
Nicolas Garcia-Aracil ◽  
Jose M. Sabater ◽  
Eduardo Fernandez
Keyword(s):  
Computer Vision ◽  
Visual Acuity ◽  
Visual Perception ◽  
Contrast Sensitivity ◽  
Visual Function ◽  
Histological Analysis ◽  
Visual Development ◽  
New Drugs ◽  
Design And Implementation ◽  
Function Design

The aim of the work presented in this paper is the design, manufacturing and assembling of a system able to measure rodents' (mice and rats) visual function and to study the evolution of degenerative retina diseases. Measurement of contrast sensitivity and visual acuity is essential to design new drugs and understand mechanisms of visual development to evaluate treatments' effectiveness. Classical methods to study visual perception of animals such as electroretinogram (ERG) or histological analysis are not supplying enough information because connection between eyes and brain is not considered. The system proposed in this work consists of four screens forming a cube with black methacrylate plastic floor and roof. Screens display visual stimulus and the rodent's behaviour (placed over a platform in the middle of the cube) is analized to determine its visual acuity and contrast sensitivity. These visual stimuli are generated from a FPGA board designed in this project. This board has a USB link with a computer and it controls screens via VGA signals. Rodents' behaviour is analized using computer vision algorithms under OpenCV libraries. To test the system, more than 30 mice (C57 and RD10 type) have been used to validate the hardware, the software, the procedure and protocol.

Prospective analysis of visual function changes in patients with dermatochalasis after upper eyelid blepharoplasty

2019 ◽  
Vol 30 (5) ◽  
pp. 978-984
Author(s):  
Meryem Altin Ekin ◽  
Seyda Karadeniz Ugurlu
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Visual Function ◽  
Spherical Aberration ◽  
Higher Order ◽  
Rank Test ◽  
Higher Order Aberrations ◽  
Upper Eyelid ◽  
Spatial Frequencies ◽  
The Difference

Objective: To evaluate the changes of visual acuity, contrast sensitivity, astigmatism, and higher order aberrations after blepharoplasty in patients with dermatochalasis. Methods: Two hundred six eyelids of 103 patients with dermatochalasis were prospectively studied. Visual acuity, contrast sensitivity, corneal topography, astigmatism degree, and higher order aberrations were examined and recorded before and at 1 month after upper eyelid blepharoplasty. Change in contrast sensitivity and astigmatism values were determined according to margin reflex distance of patients, which were classified into three following groups: <2 mm, 2–3 mm, and ⩾ 4 mm. A Wilcoxon signed rank test was performed to compare the difference. Results: No significant differences were observed for visual acuity (p = 0.157). The contrast sensitivity of patients significantly increased at all spatial frequencies both under glare and nonglare conditions (p < 0.05). The mean refractive astigmatism significantly decreased from ‒1.01 ± 1.3 to ‒0.79 ± 0.71, postoperatively (p = 0.029). In patients with marginal reflex distance < 2 mm, mean contrast sensitivity was increased (p < 0.001) and mean astigmatism was decreased significantly (p < 0.001) compared with those with ⩾ 2 mm. Higher order aberrations decreased significantly from 0.62 ± 0.41 µm to 0.55 ± 0.38 µm (p = 0.038) after blepharoplasty. Root mean square of the vertical trefoil (p = 0.038), vertical coma (p = 0.002), horizontal trefoil (p = 0.027), third-order aberration (p = 0.005), secondary vertical stigmatism (p = 0.001), spherical aberration (p = 0.023), secondary horizontal astigmatism (p = 0.002), fourth-order aberration (p = 0.024), vertical pentafoil (p = 0.015), secondary horizontal coma (p = 0.035), secondary horizontal trefoil (p = 0.030), and horizontal pentafoil (p = 0.048) were decreased significantly. Conclusion: Upper eyelid blepharoplasty in patients with dermatochalasis has a significant improvement in visual function in terms of contrast sensitivity, astigmatism, and higher order aberrations.

Visual Function during Acute Hypoglycaemia

1996 ◽  
Vol 6 (1) ◽  
pp. 81-86 ◽  
Author(s):  
H. Tabandeh ◽  
L. Ranganath ◽  
V. Marks
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Visual Function ◽  
Blood Glucose Concentration ◽  
Visual Pathways ◽  
Metabolic Disturbances ◽  
Sensitivity Testing ◽  
Hypoglycaemia Unawareness ◽  
Visual Symptoms ◽  
Binocular Function

Hypoglycaemia symptoms are of particular interest in view of the importance of hypoglycaemia unawareness. Visual symptoms arising during acute hypoglycaemia may be the result of metabolic disturbances in the visual pathways within the central nervous system or impairment of the refractive apparatus of the eye and binocular function. This study investigated the effect of hypoglycaemia upon visual acuity, binocular interaction and contrast sensitivity. Various aspects of visual function were examined in ten normal subjects before, during and after acute insulin-induced hypoglycaemia. A simultaneous study of hypoglycaemic symptoms enabled us to relate the objective findings to the symptoms as reported by the subjects. Snellen visual acuity, fusion and stereopsis were not affected by hypoglycaemia. Five subjects noted visual disturbance. Eight developed significant impairment of contrast sensitivity, which closely matched the lowered blood glucose concentration. These observations suggest that hypoglycaemic visual symptoms are due to neuroglycopenia of central visual pathways rather than changes within the refractive apparatus or abnormality of binocular function. Although these symptoms are not a constant feature of the hypoglycaemic state, subtle impairment of visual function occurs in most cases. Contrast sensitivity testing can be useful for assessment of fine changes in visual function.

scholarly journals Ophthalmic Findings and Their Effect on Visual Function in Persons with Albinism in Southern Nigeria

2019 ◽  
pp. 1-8
Author(s):  
Ihunanya Ibanga ◽  
Chinyere N. Pedro-Egbe ◽  
Alfred A. Onua ◽  
Bassey Fiebai
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Visual Function ◽  
Low Vision ◽  
Statistical Significance ◽  
P Value ◽  
Cross Sectional ◽  
Ocular Disorders ◽  
Southern Nigeria ◽  
Study Participants

Aim: To determine the pattern of ocular disorders in persons with albinism and how they affect visual function. Methods: This was a descriptive cross-sectional study conducted over a five-month period on persons living with albinism in Southern Nigeria. The study participants were randomly selected during the monthly meetings of a support group known as The Albinism Foundation (TAF).Visual acuity and contrast sensitivity were assessed using the ETDRS visual acuity chart and Pelli Robson contrast sensitivity test chart. A comprehensive eye examination including dilated fundoscopy was also carried out to determine other ocular disorders. Data was analyzed using SPSS version 22 and statistical significance was set at a p-value ≤ 0.05. Results: A total of 116 PWA (232 eyes) were examined. There were 44 (37.9%) males and 72 (62.1%) females. The age of the study subjects ranged from 5 to 56 years. Most eyes were visually impaired for both distance (n=228; 98.3%) and near vision (n= 224; 96.6%). Contrast sensitivity in most eyes (n=138; 59.5%) was subnormal. With refraction and Low Vision Aid (LVA), there was significant improvement of the mean VA by 2-3 acuity lines and 6 acuity lines respectively (p=0.000). All the examined eyes had fundus hypo-pigmentation, 91.4% (n=212) had iris trans-illumination, 86.2% (n=200) had nystagmus, and 34.4% (n=80) had strabismus. Nystagmus, strabismus and iris trans-illumination significantly (p=0.00) reduced visual acuity and contrast sensitivity. Conclusion: Most study participants had reduced distance visual acuity and contrast sensitivity but with correction there was a significant improvement in vision. The presence of nystagmus, strabismus and iris trans-illumination were observed to contribute to the poor vision experienced by most persons living with albinism. Hence, early optical intervention and counselling is important in improving the quality of living of persons with albinism.

Early glycaemic control for maintaining visual function in type 1 diabetes: The Oulu cohort study of diabetic retinopathy

2018 ◽  
Vol 28 (6) ◽  
pp. 684-689 ◽  
Author(s):  
Nina Hautala ◽  
Mira Siiskonen ◽  
Virva Hannula ◽  
Kaisu Järvinen ◽  
Aura Falck
Keyword(s):  
Visual Acuity ◽  
Type 1 Diabetes ◽  
Contrast Sensitivity ◽  
Visual Function ◽  
Glycated Haemoglobin ◽  
Haemoglobin A1c ◽  
Corrected Visual Acuity ◽  
Long Duration ◽  
Haemoglobin A1

Purpose: The purpose of this study was to evaluate the visual function and the ophthalmic status of young Finnish adults with long duration of type 1 diabetes in relation to the history of the metabolic control. Methods: A population-based cohort of children with type 1 diabetes examined in the Northern Ostrobothnia hospital district in 1989 (n = 216) was re-examined 18 years later. High-contrast visual acuity (best-corrected visual acuity), contrast sensitivity, refractive error, lens status, intraocular pressure, stage of diabetic retinopathy and received treatments were evaluated. The metabolic control was reflected by the mean of glycated haemoglobin A1 or glycated haemoglobin A1c values of the years 1983–1989 and 1992–2007, respectively. Results: In all, 96 men and 76 women age 30 ± 3 years with type 1 diabetes duration of 23 ± 4 years attended the re-evaluation. About 60% (103/172) had normal best-corrected visual acuity and 3% had low vision. Contrast sensitivity was abnormal in two-thirds. Half had myopia. Four patients had cataract surgery. Low childhood glycated haemoglobin A1 was indicative, and favourable glycated haemoglobin A1c during youth was a significant predictor of better contrast sensitivity and ocular state in adulthood. Conclusion: The majority of the patients have useful vision, although minor functional impairments are commonly detectable. Long duration of type 1 diabetes in association with non-optimal glycaemic control threatens visual function already at young adulthood. Thus, strong emphasis to control diabetes from onset is important in maintaining good visual function.

scholarly journals Reading Performance and Compensatory Head Posture in Infantile Nystagmus after Null Zone Training

2019 ◽  
Vol 16 (23) ◽  
pp. 4728
Author(s):  
Norliza Mohamad Fadzil ◽  
Zainora Mohammed ◽  
Mizhanim Mohamad Shahimin ◽  
Noor Haziq Saliman
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Visual Function ◽  
Reading Time ◽  
Reading Rate ◽  
Reading Performance ◽  
Head Posture ◽  
Infantile Nystagmus

This study aimed to assess the visual function, reading performance, and compensatory head posture (CHP) in schoolchildren with infantile nystagmus. A total of 18 participants aged between 13 to 18 years old were divided into spectacle (n = 9) and null zone group (n = 9) based on their visual acuity. Visual acuity (LogMAR), contrast sensitivity (Pelli–Robson), reading time and rate (Tobii TX300), and CHP were measured pre and post null zone reading training. Participants in the null zone group received 10 sessions of training (5 weeks). Visual acuity and contrast sensitivity of participants in the spectacle and null zone groups were not significantly different pre and post training. Reading performance, i.e., reading time (z = −1.36; p = 0.173) and reading rate (z = −0.06; p = 0.953), of participants in the spectacle group was not significantly different after 5 weeks. Reading time (z = −2.55; p = 0.011) and reading rate (z = −2.07; p = 0.038 of participants in the null zone group showed significant improvement post training. After 5 weeks, CHP improved in six out of the nine participants (66.7%) of the null zone group and was unchanged in all participants in the spectacle group. Null zone reading training could benefit children with infantile nystagmus in improving reading performance and compensatory head posture.

Visual Function and Subjective Quality of Life in Chinese Cataract Patients after Implantation with Aspheric Intraocular Lenses

2011 ◽  
Vol 21 (6) ◽  
pp. 732-740
Author(s):  
Yanwen Fang ◽  
Yi Lu ◽  
Xinhua Wu ◽  
Aizhu Miao ◽  
Yi Luo
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Visual Function ◽  
Spherical Aberration ◽  
Visual Quality ◽  
Intraocular Lenses ◽  
Subjective Quality Of Life ◽  
Significant Difference ◽  
The Mean ◽  
Cataract Patients

Purpose. To evaluate and compare the objective and subjective visual function after implantation of 2 aspheric intraocular lenses (IOLs) in Chinese cataract patients. Methods. Forty-one eyes of 28 patients with cataract were randomly assigned to receive either the MC X11 ASP IOL or the AcrySof IQ IOL. Three months postoperatively, best-corrected visual acuity (BCVA), contrast sensitivity, wavefront aberrations, and subjective visual quality were measured. The degree of posterior capsule opacification (PCO) was recorded at last follow-up. Results. Postoperative mean monocular BCVA was 0.05±0.13 logMAR in the MC X11 group and 0.05±0.08 logMAR in the IQ group. There was no significant difference in visual acuity, contrast sensitivity, subjective visual quality, and degree of PCO between the 2 groups. For a 6-mm pupil diameter, the mean spherical aberration (Z40) was 0.075±0.076 μm in the MC X11 group and 0.056±0.111 μm in the IQ group. However, 45.5% and 57.9% of the eyes in the MC X11 and IQ groups had values >0.10 μm, respectively. The mean RMS values of the high-order aberrations were similar between the 2 groups except the higher fifth- and sixth-order aberrations, which were significantly higher in the MC X11 group. Conclusions. Both IOLs provided similar and good visual outcomes. However, the data suggest that the amount of negative spherical aberration generated by current available aspheric IOLs might not be optimal for Chinese eyes.

scholarly journals Functional visual acuity after implantation of diffractive extended depth-of-focus intraocular lenses using an echelett optics

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Toshihiro Sakisaka ◽  
Keiichiro Minami ◽  
Keita Takada ◽  
Yosai Mori ◽  
Kazunori Miyata
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Visual Function ◽  
Case Series ◽  
Intraocular Lenses ◽  
Depth Of Focus ◽  
Mean Response Time ◽  
Extended Depth Of Focus ◽  
Functional Visual Acuity ◽  
The Mean

Abstract Background The prospective comparative case series aimed to evaluate all-distance visual acuity, contrast sensitivity, and functional visual acuity (FVA) of eyes with diffractive extended depth-of-focus (EDOF) intraocular lenses (IOLs) using an echelett optics and monofocal IOLs with the same platform. Methods Diffractive EDOF and monofocal IOLs were implanted in 27 eyes of 27 patients each. At 3 months after implantation, all-distance visual acuities at distances of 0.3, 0.5, 0.7, 1, 2, 3, and 5 m were measured under distance-corrected. Static visual function was also examined using photopic contrast sensitivity and area under the logarithmic contrast sensitivity function (AULCSF). Dynamic visual function was examined with FVA, and mean FVA value, visual maintenance ratio (VMR), mean response time, and number of blinks were evaluated. These outcomes were compared between the two IOLs. Results The mean distance-corrected visual acuities were better at distances of 0.7 m or nearer in eyes with EDOF IOLs. There was no difference in the contrast sensitivities (P > 0.22). In the FVA results, no difference was found in mean FVA and VMR (P > 0.68). Conclusion The static and dynamic evaluations of postoperative visual functions demonstrated that the visual function of eyes with EDOF IOLs under photopic and distance-corrected conditions was comparable to eyes with monofocal IOLs.

scholarly journals Visual Function Tests as cost Effective Screening Tools For Diabetic Retinopathy

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Faryal Ahmed ◽  
Faraz Iftikhar Malik ◽  
Chaudhary Ehtsham Azmat ◽  
Ambreen Gul ◽  
Ali Raza
Keyword(s):  
Visual Acuity ◽  
Diabetic Retinopathy ◽  
Contrast Sensitivity ◽  
Color Vision ◽  
Visual Function ◽  
Cost Effective ◽  
Screening Tools ◽  
Diabetic Patients ◽  
Effective Screening ◽  
Function Tests

Purpose:  To find out the importance of visual function tests as cost effective screening tools for diabetic retinopathy. Study Design:  Descriptive, Cross sectional study. Place and Duration of Study:  Ophthalmology Unit of Holy Family Hospital, from September 2018 to November 2018. Material and Methods:  Two hundred and forty-two patients were selected by convenience sampling technique and were divided into three groups. Two groups of diabetics with and without retinopathy and one group of non-diabetics age-matched controls. After relevant history, patients were examined for Visual acuity, Color vision and Contrast sensitivity using Snellen’s Chart, 24 Plates Ishihara Chart and Pelli Robson Chart respectively. Staging of retinopathy was done after mydriasis. Results:  Diabetic patients irrespective of type and stage, when compared with non-diabetic patients had a greater percentage of abnormal visual function tests. A 6/6 visual acuity was observed in 38.2% of non diabetics as compared to only 8.6% diabetics without retinopathy and 7.5% of diabetics with retinopathy. Color vision abnormalities were detected in only 8.6% of non diabetic patients. However, 11.1% of diabetics without retinopathy and 23.7% with retinopathy showed abnormalities of color vision. The percentage of abnormal Contrast sensitivity was 76.2% for diabetics with retinopathy and 60.4% for diabetics without retinopathy and 27.1% for non-diabetic patients. Conclusion:  Evaluation of Visual Acuity, Color Vision and Contrast Sensitivity are cheap and easy tests that can be used to screen for diabetic retinopathy thereby allowing early interventions to prevent development of serious ocular diabetic complications.

The Investigation Of The Effect Of Hyperglycaemic Changes On Psychophysical Measurements Of Visual Function In Pseudophakic People Living With Diabetes Mellitus.

2020 ◽  
Author(s):  
Lindokuhle Majola ◽  
Alvin J Munsamy
Keyword(s):  
Diabetes Mellitus ◽  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Visual Function ◽  
Health Centre ◽  
Ethics Committee ◽  
Department Of Health ◽  
Kwazulu Natal ◽  
Quasi Experimental ◽  
Visual Disturbances

Abstract Background Phakic people living with diabetes mellitus (PDM) have been known to complain of transient subjective visual disturbances, however it has yet to be shown if this can extended to pseuodphakia as well. The measurement of visual acuity (VA) and contrast sensitivity (CS) forms part for these visual disturbances and is regarded as psychophysical measurements of vision. The purpose of this study was to show the effect of increasing blood glucose level (BGL) on visual acuity and contrast sensitivity in pseudophakic PDM. Methods This was quasi-experimental, quantitative study using a pretest-posttest approach. The study was conducted at Gamalakhe community health centre and included a sample of 50 pseudophakic people living without diabetes mellitus (PWDM) and 50 pseudophakic-PDM. BGL as well as psychophysical measurements of visual function were measured pre-prandial and postprandial. VA was measured at distance (4 m) and near (40 cm) using LogMAR VA charts, CS was measured at 50 cm using Mars chart. Ethical permission was obtained before commencement of the study from Biomedical Research Ethics Committee (BREC) and KwaZulu-Natal Department of Health. The data collected was captured and subsequently analysed using the SPSS version 25. The Kruskal-Wallis Test and Wilcoxon Sign Ranked was used to compare changes within each group. Results Glycaemic changes observed had a mean increase of 2.06 ± 1.35 mmol/L and 1.08 ± 0.47 mmol/L in pseudophakia PDM and pseudophakic PWDM, respectively. A mean increase in CS of 0.01 ± 0.10 log units in PDM was found, however the independent T-Test showed this was insignificant between PDM and PWDM (p = 0.27). Mean increase in distance (0.01 ± 0.04 log units, p = 0.25) and near LogMAR VA (0.001 ± 0.01 log units, p = 0.32) for pseudophakic PDM was found, however the Mann-Whitney U-Test showed a statistically insignificant change p = 0.45 and p = 0.13 in distance and near VA respectively when compared to changes observed for pseudophakic PWDM. Conclusions Acute hyperglycaemic changes does not result in overall significant changes in visual acuity and contrast sensitivity in pseudophakic PDM for an increase in glycaemia of 2 mmol/L. However, the duration of DM may affect the CS in pseudophakic PDM without retinopathy who have had DM for greater than 10 years.

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