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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↗
PubMed1978

Visual function in acute posterior multifocal placoid pigment epitheliopathy.

We examined a 19-year-old woman with acute posterior multifocal placoid pigment epitheliopathy one week after she noted blurring of central vision. Her corrected visual acuity was R.E.: 6/7.5 (20/25), and L.E.: 6/12 (20/40). The visual fields showed 10-degree pericentral scotomas. A color vision defect and an abnormal Stiles-Crawford effect were present. Dark adaptation showed a delayed time course, with normal final thresholds. The electro-oculogram was subnormal, suggesting widespread abnormality of the retinal pigment epithelium. Active lesions resolved within three weeks, but fluorescein angiography showed characteristic widespread residual changes. Within three weeks, she had normal visual acuity and a normal electro-oculogram. Other tests of visual function showed recovery with a slower time course. By one year, the visual fields, color matching, Stiles-Crawford effect, and dark adaptation were almost normal. Analysis of the color-matching data and Stiles-Crawford effect indicated that the abnormalities of macular function were caused by an underlying lesion of the pigment epithelium and photoreceptors. This caused a physical distortion of the photoreceptor layer and metabolic disfunction of the photoreceptors.

Adult↗
PubMed2006

Psychometric performance of the National Eye Institute visual function questionnaire in Latinos and non-Latinos.

OBJECTIVE: To compare the psychometric performance of Spanish versions of the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) and the NEI VFQ-39 administered to Latino patients with the psychometric performance of the standard English NEI VFQ-25 and NEI VFQ-39 administered to non-Latino patients. DESIGN: Clinic-based cross-sectional survey. PARTICIPANTS: Four hundred three patients (160 Latinos and 243 non-Latinos) recruited from general ophthalmology clinics of an urban public hospital over a 6-month period. METHODS: Structured face-to-face interviews were conducted in Spanish and English to collect data for the NEI VFQ-25 and NEI VFQ-39. We calculated the mean, standard deviation, and percentage of participants having the minimum (floor) and maximum (ceiling) possible score for each item and scale. Internal consistency reliability of the NEI VFQ-25 and NEI VFQ-39 was estimated using the Cronbach alpha and average inter-item correlation. Construct validity for the instruments was assessed by comparing scores for participants classified as having normal versus impaired visual acuity. MAIN OUTCOME MEASURES: Instrument scales for general health; general vision; ocular pain; near activities; distance activities; vision-specific social functioning, mental health, role difficulties, and dependency; driving; color vision; and peripheral vision. RESULTS: Internal consistency reliability was significantly lower in the Spanish version than in the English version for 3 scales of the NEI VFQ-25. More importantly, 3 scales in the Spanish version manifested inadequate reliability (alpha< or =0.70), compared with only 1 inadequately reliable subscale in the English version. Reliability coefficients associated with the Spanish NEI VFQ-39 scales exceeded commonly accepted minimum standards. Comparison of reliability coefficients between Latino and non-Latino subgroups demonstrated statistically significant differences for 4 scales: Ocular Pain, Mental Health, Role Difficulties, and Dependency. In each case, the Latino group had the lower internal consistency reliability. However, only for the Ocular Pain subscale was reliability both significantly lower and inadequate (alpha<0.70). CONCLUSION: Overall performance of the NEI VFQ in Latino populations is adequate. However, in the absence of modifications to improve the reliability of specific Spanish version subscales, comparisons between Latino and non-Latino subgroups using the NEI VFQ must be interpreted with appropriate caution.

Adult↗
PubMed2003

[Loss of visual function as the result of gunshot injuries of the eye].

The article presents the clinical-and-statistical analysis of causes of visual function loss occurred after the gunshot injuries of eyes. The main cause of sight loss is the eye destruction as the result of gunshot injury (61.1%). Because of the unsuccessful treatment of posttraumatic changes in eyeball the injured eyes were removed in 38.9% of the casualties. In most cases the fragmentation and mine-explosive trauma were the cause of eye destruction. In the cases of eyeball destruction enucleation and evisceration were the main surgical interventions. In the therapy of posttraumatic changes in the injured eye (flaccid inflammatory process without tendency towards its resolution, painful syndrome as well as eyeball atrophy and subatrophy) enucleation was performed. Improvement of conservative methods in therapy of posttraumatic complications could contribute to decrease in the number of casualties with sight loss after the eye gunshot injures.

Eye Injuries↗
PubMed1984

Visual function in diabetic patients undergoing dialysis: comparison of peritoneal and hemodialysis.

A prospective, uncontrolled study was designed to evaluate the changes in visual efficiency among insulin-requiring diabetic patients undergoing peritoneal and hemodialysis. Of the 112 patients (63% adult onset and 37% juvenile onset diabetics) studied chronologically, 63% were treated with hemodialysis and 37% with peritoneal dialysis. The mean distribution of sex, age, observation period and initial visual function were the same in the peritoneal and hemodialysis subpopulations, but more juvenile onset diabetics were treated with peritoneal dialysis. Preservation of vision correlated well with overall blood pressure control in all dialysis groups. Loss of vision was independent of the dialysis modality, of glucose control, and of the type of onset of diabetes.

Blood Pressure↗
PubMedDate not supplied

Visual function during acute hypoglycaemia.

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.

Accommodation, Ocular↗
PubMed1999

Visual function correlates with nerve fiber layer thickness in eyes affected by ocular hypertension.

PURPOSE: To test whether the high variability observed when measuring pattern electroretinogram (PERG), visual evoked potentials (VEP), and spatial contrast sensitivity (SCS) in eyes with ocular hypertension is associated with variation in nerve fiber layer thickness, as measured by optical coherence tomography (OCT). METHODS: The study involved 32 untreated eyes (32 patients; age range, 29-64 years) showing a normal whiteon-white 24/2 Humphrey (San Leandro, CA) perimetry, IOP between 23 and 28 mm Hg, best corrected acuity of 20/20 or better, and none of the following papillary signs on conventional color stereo slides: rim notch(es), peripapillary splinter hemorrhages, or increased vertical-to-horizontal cup-to-disc ratio. On recruitment, each eye underwent SCS testing, OCT, PERG, and VEP recordings. Linear regression (Pearson's test) or Spearman's rank regression was adopted for the analysis of the data. RESULTS: The 95% confidence limits of the electrophysiological data were: PERG P50 latency, 59.3 to 63 msec; PERG P50 to N95 amplitude, 0.74 to 1.15 cmV; VEP P100 latency, 113 to 118 msec; VEP N75 to P100 amplitude, 3.81 to 4.90 micromV. The 360 degrees nerve fiber layer thickness overall (NFLO) ranged between 113 and 169 microm (145+/-16 microm; mean+/-SD) and significantly correlated with PERG P50 to N95 amplitude (r: 0.518; P = 0.002), PERG P50 latency (r: -0.470; P = 0.007), VEP N75 to P100 amplitude (r: 0.460; P = 0.008), VEP P100 latency (r = -0.422; P = 0.016) and SCS at 3 cyc/deg (r: -0.358; P = 0.044). CONCLUSIONS: The variability of PERG, VEP, and SCS testing observed in eyes with ocular hypertension is associated with differences in NFL thickness (the thinner the layer, the worse the visual function).

Adult↗
PubMed2004

Depression and the 25-item National Eye Institute Visual Function Questionnaire in older adults.

PURPOSE: To examine the impact of depression in older adults on responses to the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) independent of demographics, vision, and general health. DESIGN: Cross-sectional. PARTICIPANTS: We took the opportunity of an ongoing study on older drivers to address the specific aim stated above. The recruitment population consisted of 6342 older adults (> or =60 years) who were licensed drivers residing in Birmingham, Alabama; who had been involved in a crash in the prior year, as identified by Alabama Department of Public Safety records; and whose phone numbers could be located. Additional eligibility criteria were visual acuity impairment, slowed visual processing speed, or both, and a Mini-Mental State Examination score of > or =23. Persons in the recruitment population who met these eligibility criteria and agreed to enroll in a study on driver safety (purpose of the main study) numbered 403. METHODS: The following questionnaires were interviewer administered in person and scored per standard procedures: the NEI VFQ-25, the Center for Epidemiological Studies Depression Scale (CES-D), a general health questionnaire, and a review of demographic information. Depressed persons were defined as those with CES-D scores of > or =16. There were complete data on 397 persons. MAIN OUTCOME MEASURE: Reduced score on the NEI VFQ-25 (defined by a score of <87.5) on the total questionnaire and 12 subscales. RESULTS: After adjusting for demographics, vision, mental status, and general health, depression was significantly associated with a reduced NEI VFQ-25 score for total score and the subscales of distance vision, peripheral vision, role difficulties, dependencies, and mental health. Odds ratio point estimates in these adjusted associations ranged from 2.9 to 4.6. CONCLUSIONS: The results imply that older persons who are depressed may have reduced scores on the NEI VFQ-25 independent of the impact of vision problems. Depression in the elderly could be influencing their self-perception of the burden of eye disease and treatment effectiveness in clinical and epidemiologic studies.

Aged↗
PubMed1987

Analysis of binocular visual function using tests made under binocular conditions.

Accommodation and vergence have a complex relation which occasionally breaks down, resulting in a loss of visual efficiency along with symptoms of discomfort associated with use of the eyes. Studies of accommodation/vergence interactions and tonic vergence disorders indicate that, using classical analysis techniques, separate methods are frequently necessary to determine whether existing binocular deficiencies are causing reported symptoms. The problem with current systems of binocular visual function analysis is that the vergence error which exists under binocular conditions is often not the same as that which is measured under monocular conditions. A rationale for, and technique of, analyzing binocular function using results of tests made under binocular conditions is described. This analysis incorporates the concepts of CA/C, proximal vergence (PV), and fixation disparity along with several accommodative measures (facility, lag, sustaining ability, and accuracy). By identifying relevant binocular components and the interrelations, the clinician should be better able to assess the contribution of each and examine which may be modified most easily by vision therapy, lenses, and/or prism intervention.

Accommodation, Ocular↗
PubMedDate not supplied

Functional visual loss in Cambodian refugees: a study of cultural factors in ophthalmology.

South East (SE) Asians accounted for a disproportionate percentage of the functional visual loss (FVL) seen in our area between 1983 and 1987. Moreover, 94% of the SE Asian FVL patients were Cambodian, although Cambodians only represented 20-30% of the local SE Asian patient population. Cambodian refugees are, at present, generally from lower socio-economic classes than the Vietnamese, and a much larger percentage of them have a history of camp incarceration and previous trauma. The Cambodians presenting with FVL may have conversion hysteria influenced by their wartime experience and cultural background. This study demonstrates that the SE Asian refugees in California are not a homogenous group with respect to visual problems, and that an awareness of cultural or historical factors can be important to the management of ophthalmic symptoms in our multi-cultural societies.

Adult↗
PubMed1978

Pituitary adenoma and visual function. The prognostic value of clinical, ophthalmological and neuroradiologic findings in 51 patients subjected to operation.

The series studied included 51 patients subjected to operation for pituitary adenoma. The visual status was analysed both pre- and postoperatively. The pre- and postoperative parameters were compared with clinical information, ophthalmological and neuroradiological findings with a view to an evaluation of their prognostic value. In 36 patients with chromophobe adenoma, visual field defects were present in 92% before the operation; visual function improved in 62% and returned to normal in 24%. Among 15 patients with eosinophil or mixed adenoma, only two (13%) had visual field defects pre-operatively. In those patients where operation was followed by a distinct visual improvement, the pre-operative ophthalmological findings were as follows: visual acuity greater than 6/24, normal optic discs, visual field defects up to two quadrants, and pneumoencephalographic findings suggestive of only a small suprasellar tumour.

Adenoma↗
PubMed2006

The impact of modest prematurity on visual function at age 6 years: findings from a population-based study.

OBJECTIVE: To determine the effects of modest low birth weight and prematurity on visual function of children predominantly aged 6 years. METHODS: Children with a birth weight of 1500 to 2499 g were considered exposed to a modest low birth weight (n = 82) and were compared with children with a birth weight of 2500 g or more (n = 1386). Exposure to modest prematurity, 32 to 36 weeks' gestation (n = 115), was similarly analyzed and compared with birth at term, 37 or more weeks' gestation (n = 1446). Logarithm of the minimum angle of resolution visual acuity was measured in both eyes. Cycloplegic autorefraction (cyclopentolate), cover testing, and dilated fundus examinations were performed. RESULTS: A modest low birth weight increased the risk of amblyopia (relative risk [RR], 5.1; 95% confidence interval [CI], 2.2-12.0), strabismus (RR, 3.7; 95% CI, 1.5-9.1), and anisometropia (RR, 3.7; 95% CI, 1.2-11.1), together with an increased risk of uncorrected visual acuity in the lowest quartile (RR, 1.7; 95% CI, 1.3-2.2). Modest prematurity increased the risk of amblyopia (RR, 4.5; 95% CI, 1.9-10.6), strabismus (RR, 2.6; 95% CI, 1.1-6.0), and uncorrected visual acuity in the lowest quartile (RR, 1.5; 95% CI, 1.1-2.0). CONCLUSION: Modest degrees of low birth weight and prematurity may be associated with increased ophthalmic morbidity at age 6 years.

Amblyopia↗
PubMed1991

Long-term visual function in acute posterior multifocal placoid pigment epitheliopathy.

Acute posterior multifocal placoid pigment epithellopathy is a chorioretinal inflammatory disease occurring in young, healthy adults. The long-term visual prognosis and recurrence rate is uncertain. We reexamined 28 patients (53 affected eyes) with acute posterior multifocal placoid pigment epitheliopathy (mean follow-up, 8 years) to obtain details on the long-term functional visual outcome. The final visual acuities were 20/25 or better in 48 eyes (90.6%), 20/30 to 20/100 in four eyes (7.5%), and 20/200 in one eye (1.9%). Although the final visual acuity was good, 33 eyes (62.3%) were symptomatic with blurred vision, metamorphopsia, or scotomas. Thirty-six eyes (67.9%) had significant central visual field defects on follow-up examination. There were no recurrences after the initial month of symptoms. The chorioretinal scars did not enlarge with time. Acute posterior multifocal placoid pigment epitheliopathy has a good longterm prognosis for visual acuity, although most patients have residual symptoms and paracentral scotomas.

Acute Disease↗
PubMed2004

Changes in fundus autofluorescence in patients with age-related maculopathy. Correlation to visual function: a prospective study.

BACKGROUND: As members of the Fundus Autofluorescence in Age-related Macular Degeneration Study Group (FAM Study Group), we report changes of fundus autofluorescence (AF) in patients with multiple soft drusen in correlation to visual function. METHODS: Inclusion criteria were age >50 years, the presence of soft drusen, visual acuity of 20/100 or better, and no previous laser treatment in the study eye. All patients underwent a detailed ophthalmological examination including ETDRS visual acuity, binocular funduscopy, and color fundus photography. AF imaging was performed with a confocal scanning laser ophthalmoscope following a standard protocol. We used the classification of the International Fundus Autofluorescence Classification Group (IFAG) for the description of the AF patterns. RESULTS: One hundred and twenty-five patients (81 women, 44 men) aged from 55 to 86 years (mean 70+/-7 years) were included in this prospective study. During follow-up (mean 18+/-6 months), 6 of 35 eyes with patchy AF pattern developed exudative changes, as well as 2 eyes with focal-plaque-like AF pattern and 1 eye with reticular pattern at baseline. Geographic atrophy was seen in two eyes with focal AF pattern and one eye with focal-plaque-like pattern at baseline. A total of 11 eyes presented with severe visual loss (> or = 6 ETDRS lines). Ten (91%) of these had patchy AF pattern. CONCLUSION: Imaging of fundus AF in patients with age-related maculopathy allows identification of different patterns of fundus AF. Our preliminary data suggest that a patchy pattern of AF indicates a relatively high risk of progression to age-related macular degeneration with visual loss.

Aged↗
PubMed2005

Measuring outcomes of cataract surgery using the Quality of Well-Being Scale and VF-14 Visual Function Index.

PURPOSE: To evaluate the validity and responsiveness of the self-administered Quality of Well-Being Scale (QWB-SA) and the 14-item Visual Function Index (VF-14) to assess patients having cataract surgery. SETTING: Large Southern California health maintenance organization. METHODS: This study comprised 233 adults who had uneventful small-incision (< 3.0 mm) phacoemulsification cataract extraction under local anesthesia. Patients were assessed before surgery as well as 4 to 6 weeks and 4 months after surgery using the QWB-SA and the VF-14. RESULTS: Postoperatively, patients reported significant improvements on QWB-SA (P < .005) and VF-14 (P < .001) measures. Those grouped by visual acuity in the operated eye and unoperated eye and first-eye surgery or second-eye surgery had significant changes in VF-14 results (P < .001). Improvements on the QWB-SA were significant except when the preoperative visual acuity was better than 20/40 in the operated eye or 20/50 in the unoperated eye and when patients had first-eye surgery. The vision-specific VF-14 was more sensitive to improvements after surgery than the more general QWB-SA. Both demonstrated a greater magnitude of change with lower baseline scores and correlated significantly with self-reported satisfaction and trouble with vision. CONCLUSIONS: Both the utility-based generic QWB-SA and disease-specific VF-14 profile were responsive to changes in quality of life after cataract surgery. The VF-14 was more sensitive to change but cannot be used for comparison across disease states or for policy analysis. The QWB-SA can be used to estimate the cost/utility of cataract surgery.

Adult↗
PubMed1996

Establishing a reliable visual function test and applying it to screening optic nerve disease in onchocercal communities.

The computer Controlled Video Perimetry (CCVP) is a computer screening test for detecting visual function loss caused by onchocerciasis, glaucoma, etc. Installed on portable computers, the CCVP has been shown to be high acceptability in field community investigation. However, it is regarded to be difficult in obtaining reliable results from portable computer screening tests because of human behavioural variants and the lack of standard testing environment. In this paper, we propose an architecture for implementing a more reliable CCVP system. In particular, a self-organising neural network is applied to manage measurement noise caused by behavioural factors. A control unit is introduced to manage the overall behaviour of the system. The integrated test system has been used to screen optic nerve disease in onchocercal communities of rural Nigeria and the experimental results obtained from a large number of test records are very encouraging: reliable results from volatile test environments may be obtained using the proposed method.

Artifacts↗
PubMed1989

Differential development of two visual functions in primates.

Psychophysical data suggest that spatial resolution and spatial position sensitivity may be limited by different neural mechanisms. We investigated this hypothesis from a developmental perspective by studying the development of these two kinds of visual performance in two groups of infant macaque monkeys (Macaca nemestrina), one normal and one given an experimental strabismus. The results show that these two visual functions develop at different rates in normal monkeys and are disrupted differentially by abnormal early visual experience. However the relationship between the two measures is the same in strabismic and normally reared monkeys; the performance of strabismic monkeys resembles that of younger normal monkeys.

Aging↗