MyMedR

Displaying all 6 publications

Abstract:

Sort:

Fulltext Comparison on testability of visual acuity, stereo acuity and colour vision tests between children with learning disabilities and children without learning disabilities in government primary schools

Abu Bakar NF, Chen AH

Indian J Ophthalmol, 2014 Feb;62(2):141-4.
PMID: 24008790 DOI: 10.4103/0301-4738.116481

Children with learning disabilities might have difficulties to communicate effectively and give reliable responses as required in various visual function testing procedures.

Matched MeSH terms: Vision, Binocular/physiology*
Multifocal frequency-doubling pattern visual evoked responses to dichoptic stimulation

Rosli Y, Maddess T, Dawel A, James AC

Clin Neurophysiol, 2009 Dec;120(12):2100-2108.
PMID: 19846337 DOI: 10.1016/j.clinph.2009.09.006

OBJECTIVE: To examine the feasibility of a multifocal visual evoked potential (mfVEP) binocularly, using a variant of the multifocal frequency-doubling (FD) pattern-electroretinogram (MFP).
METHODS: Stimuli were presented in both monocular and dichoptic conditions at eight visual field locations/eye. The incommensurate stimulus frequencies ranged from 15.45 to 21.51 Hz. Five stimulus conditions differing in spatial frequency and orientation were examined for three viewing conditions. The resulting 15 stimulus conditions were examined in 16 normal subjects who repeated all conditions twice.
RESULTS: Several significant independent effects were identified. Response amplitudes were reduced for dichoptic viewing (by 0.85 times, p<4 x 10(-11)); offset by increases in responses for between eye differences of one octave of spatial frequency: lower (1.15 times, 0.1 cpd); higher (1.29 times, 0.4 cpd), both p<1.8 x 10(-7). Crossed orientations produced significant effects upon response phase (p=0.023) but not amplitude (p=0.062).
CONCLUSIONS: The results indicated that dichoptic evoked potentials using multifocal frequency-doubling illusion stimuli are practical. The use of crossed orientation, or differing spatial frequencies, in the two eyes reduced binocular interactions.
SIGNIFICANCE: The results indicate a method wherein several spatial or temporal and frequencies per visual field region can be tested in reasonable time using a multifocal VEP using spatial frequency-doubling stimuli.

Matched MeSH terms: Vision, Binocular/physiology
Fulltext The consistency of retinal image size measurement using smartphone application

Nura Syahiera Ibrahim, Firdaus Yusuf @ Alias, Norsham Ahmad

Malaysian Journal of Medicine and Health Sciences, 2020;16(3):15-20.
MyJurnal

Introduction: Unequal retinal image size (RIS) or aniseikonia is usually related with anisometropia. Higher dif- ferences of RIS may manifest symptoms such as dizziness, headache or disorientation. In worst case might cause suppression that leads to amblyopia. Current study aims to evaluate the consistency of aniseikonia measurement in Smart Optometry smartphone application among myopic, hyperopic, and astigmatic simulated anisometropia and real anisometropia groups. Methods: Fifteen real anisometropes (refractive error; -0.50 until -6.00 diopters; D) and fifteen emmetropes (refractive error: -0.25 until +0.50D) were recruited. Real anisometropes wore their habitual spectacle correction while each emmetropes were fitted using soft contact lenses of +4.00DS, -4.00DS and -4.00DC with base curve 8.6 and total diameter 14.2mm in random order to mimic myopic-, hyperopic- and astigmat- ic-anisometropia before testing. Participants with any ocular disease and binocular vision problem were excluded. The consistency of aniseikonia measurement was determined in two visits, separated by at least 24-hour interval. Three repetitive measurements were taken in each visit. Results: Independent t-test and paired t-test showed that real and simulated anisometropia gave insignificant aniseikonia percentage, p>0.05. ICC findings revealed moder- ate-to-good agreement for all simulated and real groups. Bland Altman analysis between two visits exhibited good agreement among all simulated group; myopic (mean difference 0.2047; 95%CI:-1.1386-1.549), hyperopic (mean difference 0.2200; 95%CI:-0.9286-1.3686) and astigmatic (mean difference 0.2533; 95%CI:-0.7114-1.2180). Real anisometropes demonstrated good agreement with bias value of 0.2247(95%CI:-0.9162-1.3656) using Bland Altman plot. Conclusion: Smart Optometry application provides consistent measurement of aniseikonia regardless any types of anisometropia.

Matched MeSH terms: Vision, Binocular
Fulltext Spectral sensitivity in eyes with macular holes and their fellow eyes

Sharanjeet-Kaur, O'Donaghue E, Murray IJ

Clin Exp Optom, 2003 Nov;86(6):385-9.
PMID: 14632615 DOI: 10.1111/j.1444-0938.2003.tb03083.x

BACKGROUND: This prospective study was undertaken to investigate whether spectral sensitivity can be useful in determining the prognosis of fellow eyes of eyes with macular holes.
METHODS: Spectral sensitivity measurements using a one degree test spot presented at a rate of 1 Hz and 25 Hz on a bright (1000 td) white background were carried out on 10 patients aged between 67 and 74 years (mean age 70.3 +/- 2.6 years). Each patient had a full thickness macular hole in one eye and a normal contralateral fellow eye. The spectral sensitivity measurements were made with eccentric fixation in the eyes with macular holes and with central fixation in the normal fellow eye. A year later, the patient files were reviewed to look at the patient's ocular condition. Another 10 subjects between the ages of 50 and 80 years (mean age 69.5 +/- 4.2 years) were also seen. These control group subjects had visual acuities of 6/9 or better with minimal ocular media changes and no ocular or systemic pathology that could affect colour vision.
RESULTS: The 1 Hz and 25 Hz spectral sensitivities of all patients were reduced for both eyes. Despite the good eye without a macular hole having a VA of 6/6, the spectral sensitivity was similar to that of the eye with the macular hole and markedly reduced visual acuity.
CONCLUSION: The present investigation enabled us to examine the chromatic and achromatic mechanisms by testing spectral sensitivity at 1 Hz and 25 Hz, respectively. The data revealed that both chromatic and achromatic processing could be damaged in the eye with a macular hole. Surprisingly, the spectral sensitivities of both 1 Hz and 25 Hz are equally reduced in the good fellow eye with no macular hole. A one-year follow-up showed that two of the 10 patients (20 per cent) did eventually develop a macular hole in the normal fellow eye. This indicates that there is some subclinical foveal dysfunction in the normal fellow eye, the nature of which is unclear.
Study site: Manchester Royal Eye Hospital (MREH), United Kingdom

Matched MeSH terms: Vision, Binocular
Fulltext Visual and binocular status of Down syndrome children in Malaysia

Mohd-Ali B, Mohammed Z, Norlaila M, Mohd-Fadzil N, Rohani CC, Mohidin N

Clin Exp Optom, 2006 May;89(3):150-4.
PMID: 16637969 DOI: 10.1111/j.1444-0938.2006.00033.x

Down syndrome is a common chromosomal anomaly. Few reported studies make reference to the ocular status in Asian children with Down syndrome. The purpose of this study was to determine the visual and binocular status of a sample of Down syndrome children in Malaysia.

Matched MeSH terms: Vision, Binocular/physiology*
A comparison of autorefraction and subjective refraction with and without cycloplegia in primary school children

Choong YF, Chen AH, Goh PP

Am J Ophthalmol, 2006 Jul;142(1):68-74.
PMID: 16815252 DOI: 10.1016/j.ajo.2006.01.084

To evaluate the accuracy of autorefraction using three autorefractors comparing to subjective refraction in diagnosing refractive error in children.

Matched MeSH terms: Vision, Binocular