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PubMed1976

Developing visual function in the red jungle fowl embryo.

The onset of visual system function in the wild red jungle fowl embryo was measured by the pupillary reflex technique and compared with its domesticated descendant, the domestic chick. The first neurally mediated pupillary reflex in the jungle fowl embryos was found at Day 15 of incubation after 77% of incubation was completed. This point did not differ significantly from the onset of this reflex in the domestic chick embryo (after approximately 83% of incubation). Thus, it was concluded that the relatively late onset of overt visual system function in the chick, as compared with several other precocial avian species, was not a result of its history of intense domestication but rather was most likely a normal characteristic of this and other closely related species.

Age Factors↗

PubMed2002

[Evaluation of the visual function in employees working with computers].

PURPOSE: To evaluate the effects of long-term work with computer monitor on the accommodation, convergence, stereopsis, near and distant visual acuity. MATERIAL AND METHODS: The studies of the accommodation, convergence, stereopsis, near and distant visual acuity have been performed in 50 employees working with the computer 6.5 hours daily, 5-6 days weekly and 5 to 12 years. The same studies have been performed in 50 white-collar workers, who had no contact with the computer in their work. RESULTS: No changes in the accommodation, convergence, stereopsis, near and distant visual acuity have been found in the employees in both studies groups. CONCLUSION: Long-term work with the computer monitor does not cause changes in the visual function of the employees. Reported changes are probably cause by the visual fatigue associated with the near work, and not by the direct influence of the computer monitor.

Accommodation, Ocular↗

PubMed2003

The Italian version of the 25-item National Eye Institute Visual Function Questionnaire: translation, validity, and reliability.

OBJECTIVE: To test the Italian adaptation of the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ 25) and to investigate its validity and reliability. METHODS: This prospective observational study enrolled nonhospitalized patients with 1 of 5 chronic eye diseases, and a reference sample of subjects without eye diseases. Eligible participants had to be cognitively able to respond to a health status interview and be affected by 1 of the following eye conditions: senile cataract, age-related macular degeneration, glaucoma, diabetic retinopathy, and cytomegalovirus retinitis or low vision. A control group was composed of subjects with no evidence of underlying eye diseases. The Italian self-administered versions of Medical Outcomes Study Short Form and of the NEI-VFQ 25 were administered to all participants. Reliability and validity of the Italian translation of the NEI-VFQ 25 were tested using statistical methods. RESULTS: Statistical analysis points out that the Italian version of the NEI-VFQ 25 has good validity, discriminatory power, internal consistency, and reliability. CONCLUSIONS: This Italian version of the NEI-VFQ 25 shows psychometric properties comparable to those of the American version, and thus can be used in clinical research as a specific measure of quality of life in patients with chronic eye diseases.

Case-Control Studies↗

PubMed1997

Validation of French-language versions of the Visual Functioning Index (VF-14) and the Cataract Symptom Score.

OBJECTIVE: To produce and validate French-language versions of the Visual Functioning Index (VF-14), the Cataract Symptom Score (CSS) and two global measures of trouble and satisfaction with vision. DESIGN: Survey by means of telephone interviews conducted 2 weeks apart. SETTING: Ophthalmology clinic of a teaching hospital in Montreal. SUBJECTS: Subjects were recruited among patients with ocular media opacities, such as cataracts and corneal opacities. Of the 71 subjects recruited, 66 (41 French-speaking and 25 French- and English-speaking) completed the study. OUTCOME MEASURES: Visual acuity, scores on vision-related questionnaires and on the 36-Item Short-Form Health Survey (SF-36), a measure of perceived health status. RESULTS: The integral consistency of the French-language versions of the VF-14 and the CSS was high, with Cronbach alpha values of 0.96 and 0.82 respectively. The fidelity with regard to the English-language version, the test-retest reproducibility and the interrater agreement were high (intraclass correlation coefficients > or = 0.80). The correlation between the visual acuity of the better eye and the mean score on all four vision-related measures was statistically significant (p < or = 0.05). The VF-14 scores were also correlated with the score on five of the eight SF-36 subscales (p < or = 0.05). CONCLUSIONS: Our results show that French-language versions of the VF-14, CSS and global measures of trouble and satisfaction with vision are reliable and valid.

Adult↗

PubMed1998

Oscillopsia: visual function during motion in the absence of vestibulo-ocular reflex.

OBJECTIVES: To investigate (1) the effects of loss of vestibular function on spatiotemporal vision and (2) the mechanisms which enable labyrinthine defective (LD) patients to adapt to oscillopsia. METHODS: Visual function and eye movements were assessed in seven normal subjects and four LD patients with oscillopsia due to absent vestibulo-ocular reflex. Temporal vision was assessed by measurement of threshold sensitivity for detection of a target which moved across a flickering, spatially uniform background field. Spatial vision was investigated by measurements of threshold sensitivity for the detection of a target moving across a spatially modulated background in the form of square wave gratings. Velocity discrimination was assessed with drifting gratings. All measurements were made under static conditions and during oscillatory movement of either the visual stimulus or the subject (1 Hz, peak velocity 50 degrees/s). RESULTS: Temporal responses--Normal subjects and LD patients exhibited similar responses while static and under body oscillation. Spatial responses--The two groups achieved similar results under static conditions but body oscillation reduced threshold sensitivities and shifted the spatial response function towards lower spatial frequencies in the LD patients only. Similar changes in the spatial responses were seen during oscillation of the visual stimulus but these occurred in both normal subjects and LD patients. Velocity discrimination--Two LD patients achieved normal velocity discrimination but the other two showed abnormal responses to visual stimulus movement; one displayed a loss of velocity discrimination during whole body oscillation, and the other mismatched the velocity of two moving grating stimuli. CONCLUSIONS: The changes in the spatial responses are attributed to the presence of retinal slip during visual stimulus motion in all subjects or body oscillation in the LD patients. It is concluded that any visual adaptation to oscillopsia achieved by the LD patients does not influence the measured spatial response functions, which arise at an early stage of visual processing. The abnormal velocity discrimination may relate to the progressive improvement in oscillopsia reported by LD patients.

Adult↗

PubMed2000

Evaluation of the myosin VIIA gene and visual function in patients with Usher syndrome type I.

Usher syndrome type I (USH1) is a recessively-inherited disorder consisting of retinitis pigmentosa, profound congenital deafness, and vestibular ataxia. It can be caused by mutations in at least six different loci (USH1A-1F). The gene encoding human myosin VIIA (MYO7A) is the USH1B locus. In this study, 66 unrelated patients with USH1 were evaluated for defects in MYO7A using single-strand conformation polymorphism analysis and direct genomic sequencing. Twenty-nine per cent of cases were found to have likely pathogenic MYO7A mutations. A total of 22 likely pathogenic changes were identified, 18 of which were novel. Cosegregation analysis of mutations in five available families showed that the MYO7A changes segregated with the disease in an autosomal recessive fashion. Average visual function as measured by visual acuity, visual field area, and ERG amplitude was not significantly different between the group of patients with likely pathogenic MYO7A changes and the group in which no likely pathogenic MYO7A changes were detected.

Adult↗

PubMed1990

[Dynamics of visual functions in the conditions of glow and sodium lighting. I. Visual acuity, accommodation, flicker fusion, visual field and heterophoria].

Investigations of the functions cited in the title were performed in 23 persons with a normal visual system in conditions of equal illumination, first the glow and the next day or later--the sodium one. All the tests were carried out three times in the morning hours evaluating in this way their dynamics as the time goes. The authors are analyzing the degree of the variability of the discussed functions in the time, as well as their behaviour in conditions of applied illumination. The results obtained suggest that in conditions of illumination by a high-pressure sodium lamp no negative characteristics of this source of light emerged. Deterioration of a small degree was observed only in the range of accommodation for near.

Accommodation, Ocular↗

PubMedDate not supplied

Alteration of visual function in impaired glucose tolerance.

People with impaired glucose tolerance are considered to be prone to diabetes. To evaluate their visual function we investigated colour vision with the Farnsworth-Munsell 100 Hue test and contrast sensitivity with Arden's grating cards in people with imparied glucose tolerance (IGT), people with normal glucose tolerance (NGT) and others with type II diabetes (NIDDM). Eyes with low vision or any anterior or posterior segment abnormalities were excluded. Contrast sensitivity and color vision differed significantly between the groups (p < 0.01). It thus appears that patients with IGT but without clinical diabetes could be followed up to see whether these alterations have any predictive value for the development of diabetes and diabetic retinopathy.

Color Perception↗

PubMed1999

Visual function in term infants with hypoxic-ischaemic insults: correlation with neurodevelopment at 2 years of age.

AIMS: To determine if there is any association between the findings of visual assessment performed at the age of 5 months and neurodevelopmental outcome at the age of 2 years in children who have sustained hypoxic-ischaemic insults. METHODS: Twenty nine term infants with hypoxic-ischaemic encephalopathy and/or brain lesions on neonatal magnetic resonance imaging (MRI) were prospectively evaluated. At 5 months of age all the infants had their visual function assessed using the Atkinson Battery of Child Development for Examining Functional Vision, which includes the assessments of optokinetic nystagmus (OKN), acuity, visual fields, fixation shift and phase and orientation reversal visual evoked potentials. At 2 years of age the children had a structured neurological evaluation and a Griffiths developmental assessment. RESULTS: There was good correlation between the extent of the early detected visual impairment and both neuromotor and global development. Children with more than three out of five abnormal visual tests at 5 months of age tended to have abnormal neurological examination results and abnormal developmental quotients. Children with three or fewer abnormalities tended to have developmental quotients in the normal range; the level of their performance, however, was still related to the number of visual tests passed. CONCLUSIONS: Individual visual tests can provide important prognostic information. While abnormal OKN and acuity were always associated with abnormal outcome, normal results on visual evoked potentials and fixation shift tended to be associated with normal outcome.

Brain↗

PubMed1993

Visual function in children with developmental disabilities.

Vision involves a process of maturation that occurs in early childhood. Early recognition of visual disorders such as amblyopia is necessary to assure prompt treatment and optimize visual potential. This is especially important in children with developmental disabilities, in whom there is a high prevalence of such problems. Certainly, the type of ocular disorder varies according to the type of disability. But individual ophthalmic assessment is important, regardless of diagnosis, to identify treatable conditions that may improve or maximize visual function. In addition, ophthalmic examination may reveal distinctive anomalies in cases in which the etiology of disability has been difficult to establish. The present level of expertise and technology allows a comprehensive ophthalmic assessment to be performed, regardless of a child's level of impairment or ability to cooperate.

Child↗

PubMed2002

Binocular visual function in congenital esotropia after bilateral medial rectus recession with loop suture.

PURPOSE: Our aim was to evaluate the binocular visual function in congenital esotropia after bimedial rectus recession with loop suture and to address the factors that could take part in the attainment of binocular function. SUBJECTS AND METHODS: Forty children with congenital esotropia who were operated on between 12 and 48 months of age were included in the study group. Postoperative follow-up ranged from 2 to 10 years. In order to determine the factors affecting the sensory results in congenital esotropia, we classified our patients into two groups according to their fusion status. We compared the preoperative and postoperative characteristics of patients in these two groups. RESULTS: Twenty-one of 40 patients (52.5%) fused the Worth four-dot at near (Group 1), 19 patients (47.5%) did not (Group 2) at the final examination. No patient showed evidence of stereopsis. We found significant differences between these two groups in respect to the final angle of vertical deviation, the age at surgery, the presence of postoperative inferior oblique overaction, dissociated vertical deviation and abnormal head position. Correlation analysis revealed that early alignment of the eyes and the absence of postoperative vertical deviation were associated with increased incidence of achieving some degree of binocular vision. CONCLUSION: In congenital esotropia, not all infants may have the potential for normal binocular function owing to yet unknown constitutional factors. We determined that achieving some degree of binocular function may be related to early alignment of the eyes. Additionally, close follow-up and precise treatment of the accompanying vertical deviation, especially inferior oblique overaction and dissociated vertical deviation, in a timely manner may enhance the attainment of binocular sensory function.

Child, Preschool↗

PubMed1992

[Visual function damage in primary open angle glaucoma (POAG) in relation to hemorheology, ocular rheograph and other factors].

Researches of glaucomatous visual damage, hemorheology, ocular rheograph and other multiplex factors, with computed multifactorial stepwise regression analysis, indicate that elevation of intraocular pressure (IOP) is not the only factor to induce visual impairment. POAG patients are shown to have markedly reduced diastolic perfusion pressure in the ophthalmic artery, besides prolonged filling time of the retinal artery and vein, diminished erythrocyte deformability and increased platelet adhesion rate. The characteristic ocular rheographic changes in POAG patients of controlled IOP suggest that hemorheological factors play a role in the visual function damage.

Adult↗

PubMed1996

Visual function after laser hyperthermia and chemotherapy for macular retinoblastoma.

PURPOSE: To determine whether treatment of macular retinoblastoma with chemotherapy and laser hyperthermia can lead to satisfactory visual acuity. METHODS: A child with unilateral macular retinoblastoma was treated with chemotherapy and laser hyperthermia. Visual function was assessed one year after treatment. RESULTS: At age 25 months, the patient had normal visual behavior and a normal spatial-sweep visual-evoked potential. CONCLUSION: Treatment of macular retinoblastoma with chemotherapy and laser hyperthermia may enable recovery of satisfactory visual acuity.

Antineoplastic Combined Chemotherapy Protocols↗

PubMedDate not supplied

[Mean-term variations of visual function of video display terminal operators: observations on 70 cases].

The aim of the study was to evaluate medium-term variations of visual functions in VDT operators and their possible relationship to VDT exposure. The clinical records of 70 VDT operators attending our outpatient service for periodical ergophthalmological evaluation were reviewed in order to evaluate the variation of some visual parameters after a two-years follow-up. These included refraction, phorias, fusional convergence and divergence, stereopsis. The group did not include subjects affected by hyperopia, large ametropias, or binocular vision disturbances and was divided into two subgroups: low exposure group (n = 20; < 4 hours/day) and high exposure group (n = 50; exposure > 4 hours/day). Asthenopia was frequent in both groups. Variation of refraction and binocular vision parameters were absent or rather limited in both exposure groups. This seems to indicate that in subjects without significant ophthalmological problems the risk of permanent functional damage is very low at medium-term.

Adult↗

PubMed1991

Does the lymph drainage from the head influence aqueous humour outflow and visual functions?

Effect of lymphoedema of the head on the central nervous system is known. Possible changes in intraocular pressure, tonogram, electroretinogram, visual functions and ophthalmologic state was studied in animal experiments and in patients following serious surgical impairment of the cervical lymph drainage. Lymph drainage from the orbit to the deep cervical lymphatics was established, while no ophthalmologic alteration was detected after surgery.

Animals↗

PubMed2000

[Improvement of visual function after balloon angioplasty for innominate artery stenosis: a case report].

Occlusive disease of the innominate artery is relatively rare, but visual disturbance is a frequently encountered manifestation of this disease. A 48-year-old man presented with a 1-year history of right amaurosis fugaxs. During the nine years prior to admission, the patient had undergone aortic artery-coronal artery bypass surgery two times. Upon ophthalmological examination, the patient was found to have impaired right retinal sensitivity and prolonged right arm-to-retina circulation time. Aortic arch angiography demonstrated severe stenosis of the innominate artery near its origin. The stenosis was successfully treated by balloon angioplasty. Subsequently, right retinal sensitivity improved and right arm-to-retina circulation time normalized following the procedure. These findings indicate that this patient had sufferred impaired visual function due to hemodynamic retinal ischemia caused by innominate artery stenosis.

Angioplasty, Balloon↗

PubMed1989

[Postoperative recovery of visual function in sella tumors: prognostic assessment by electro-ophthalmologic studies].

Preoperative examination of the visual system in patients with tumors of the sellar region is usually limited to checking the visual acuity, assessing the visual field, and ophthalmoscopy of the optic disc. In addition to these tests we investigated pre- and postoperatively 35 patients with meningiomas, pituitary adenomas and other sellar and parasellar tumors by recording the pattern electroretinogram (PERG) and the pattern-evoked cortical potential (PVECP) in order to evaluate functional and possible structural impairment of the visual pathway. Based on electro-ophthalmological tests, the retinal and cortical findings were classified as: regular ERG and VECP (0), regular ERG and irregular VECP (1), irregular ERG and VECP (2). Up to six months postoperatively, eyes with alteration of the VECP alone (category 1) showed recovery of visual function, while those with alteration of ERG as well (category 2) did not recover in visual function. Since loss of the PERG or long-lasting alteration of it is indicative of irreversible impairment of the inner retinal layers including the retinal ganglion cells, repeat examination of the pattern ERG is recommended in disturbances caused by alterations in the central nervous system.

Adenoma↗

PubMed2001

Effect of preoperative pupil measurements on glare, halos, and visual function after photoastigmatic refractive keratectomy.

PURPOSE: To prospectively assess the effect of preoperative variables such as pupil size on glare, halos, and visual function after photoastigmatic refractive keratectomy (PARK). SETTING: Department of Ophthalmology, Stanford University School of Medicine, Stanford, California, USA. METHODS: Ninety-three eyes had PARK for primary compound myopic astigmatism. Preoperative pupil diameters were measured under scotopic and photopic illuminance conditions. Postoperatively, patients were evaluated at 1, 3, 6, 9, 12, 18, and 24 months. A regression model was performed to evaluate the predictive value of assessing preoperative variables such as pupil diameter on the development of glare and halos, contrast sensitivity, and best spectacle-corrected visual acuity (BSCVA) under scotopic, photopic, and glare conditions. RESULTS: The greater magnitude loss of BSCVA under scotopic conditions in the early postoperative period as well as the slower recovery to preoperative levels in eyes with larger scotopic pupil diameters were not statistically significant (P >.05). An increase in symptoms of glare was related more to the attempted level of spherical equivalent (SE) correction than to the pupil size during the first 12 postoperative months (P <.01). The photoablation dimensions as determined by the attempted level of astigmatic correction may result in decreases in the glare BSCVA up to 12 months after PARK (P =.03). At the 2 year follow-up, pupil diameter under both scotopic and photopic illuminance conditions was not predictive of any of the measured outcomes variables. CONCLUSIONS: An assessment of preoperative pupil size and the attempted level of both SE and astigmatic correction may be useful in identifying patients at risk of developing symptoms or declines in visual performance after PARK. However, follow-up studies are indicated to identify variables predictive of poor visual outcomes following excimer laser refractive surgery.

Adaptation, Ocular↗