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A nationwide population-based survey on visual acuity, near vision, and self-reported visual function in the adult population in Finland.
PURPOSE: To estimate the prevalence rates of habitual visual acuity (VA) levels and visual impairment in Finland and to assess their correlation with self-reported visual function. DESIGN: Cross-sectional population-based study. PARTICIPANTS: Subjects were selected randomly from the Finnish population aged 30 years or older. Of 7979 eligible people, 7393 (93%) were interviewed, 6771 (85%) were examined, and 6663 (84%) had distance VA assessed. METHODS: Participants underwent a home interview and a comprehensive examination including measuring binocular VA for distance and for near with the participants' current spectacles, if any. MAIN OUTCOME MEASURES: The level of VA for distance and for near with current spectacle correction. The self-reported capability to read newsprint and television text and the ability to move about without being restricted by reduced vision. RESULTS: The prevalence of good to moderate VA for distance (VA> or =0.5 [> or =20/40]) measured with current spectacles was 95.9%, and 87.4% had a VA level of 0.8 (20/25) or better. The prevalence of habitual visual impairment (VA< or =0.25 [< or =20/80]) was 1.6%, and 0.5% were blind (VA<0.1 [<20/200]). The prevalence of visual impairment increased significantly with age (P<0.001), especially in the age group of 65 to 74 years and upward. There was no gender difference in VA for distance, but decreased near vision (VA< or =0.25 [< or =20/80]) was significantly more common in men than in women (P<0.01). By applying the imputated numbers of visually impaired and blind participants to the Finnish population (approximately 3 million aged 30 years or older), there were approximately 65000 (2.1%) visually impaired and 17000 (0.6%) blind adult persons in the country in 2000. The correlation between self-reported visual ability and measured visual function was moderate but statistically significant (r = 0.27-0.40; P<0.0001). The proportion of people with reading difficulties or who were unable to read newsprint has decreased 7% during the last 2 decades. CONCLUSIONS: Functional visual impairment increased with age especially in the age group of 65 to 74 years and upward and was as prevalent in women as in men. The prevalence of people with reading difficulties has decreased considerably since 1980.
Posterior sub-Tenon's capsule injection of triamcinolone acetonide prevents panretinal photocoagulation-induced visual dysfunction in patients with severe diabetic retinopathy and good vision.
PURPOSE: To evaluate prospectively the efficacy of a single sub-Tenon's capsule injection of triamcinolone acetonide (TA) against panretinal photocoagulation (PRP)-induced macular thickening and visual disturbance in patients with severe diabetic retinopathy and good vision. DESIGN: Prospective, comparative, interventional case series. PARTICIPANTS: Twenty eyes of 10 patients with severe nonproliferative diabetic retinopathy or non-high-risk proliferative diabetic retinopathy whose visual acuity was 20/40 or better (<0.3 in logarithm of the minimum angle of resolution [logMAR] acuity) before the PRP, whose retinopathy was bilateral and symmetrical. The averaged parafoveal retinal thickness was more than 300 microm, leading to a worse visual prognosis after PRP. INTERVENTION: Sub-Tenon's capsule injection of 20 mg TA. MAIN OUTCOME MEASURES: Best-corrected visual acuity (BCVA) with logMAR chart and averaged foveal thickness (FT) using the retinal mapping program of optical coherence tomography. METHODS: In all patients, PRP was performed every other week for 4 sessions on both eyes, and 1 week before PRP; 1 eye received the TA injection, and the other eye served as a control. The clinical course of BCVA and FT was monitored for up to 24 weeks after beginning PRP. RESULTS: Before TA injection, BCVA and FT were 0.055+/-0.072 and 235.5+/-37.5 microm in the TA-injected eye and 0.065+/-0.071 and 233.7+/-39.8 microm in the control eye, respectively; there was no significant difference between eyes. After the TA injection, FT in the TA-injected eyes was significantly decreased. During and after the PRP, FT in the control eye increased dramatically and reached 312.0+/-68.2 microm at 24 weeks, which was significantly different from that in the TA-injected eyes (235.3+/-38.6 microm at 24 weeks). Best-corrected visual acuity in the control eye decreased with time to 0.24+/-0.13; in contrast, and BCVA in the TA-injected eye was good (to 0.085+/-0.11) . CONCLUSIONS: As a pretreatment for PRP, a single sub-Tenon's capsule injection of TA has beneficial effects for preventing PRP-induced foveal thickening and visual dysfunction in patients with severe diabetic retinopathy and good vision.
Cost utility for penetrating keratoplasty in patients with poor binocular vision.
PURPOSE: Cost-utility and cost-effectiveness analyses are of increasing importance to clinicians and health policy experts. This study determines the costs in Germany and other countries in relation to gain of utility for patients with bilateral poor vision owing to corneal disease undergoing penetrating keratoplasty (PK) in 1 eye. DESIGN: A cost-utility analysis was performed using retrospective clinical data and high-level evidence-based data. PARTICIPANTS: Sixty patients (mean age, 46.3 years) with bilateral poor vision who underwent PK for corneal disease. METHODS: Visual acuity and utility values were obtained before and 1 year after PK and after suture removal. A 10-year graft survival rate of 80% was assumed. Expenses included costs for the corneal transplant and surgery, medication, and optical rehabilitation. A discount rate of 5% was applied for costs and quality-adjusted life years (QALYs). Cost-utility analysis encompassed a 10-year period after surgery. MAIN OUTCOME MEASURES: The number of QALYs was calculated for the study group undergoing PK. This was divided into the cost of the procedure to get the number of euros spent per QALY gained. RESULTS: Median binocular preoperative visual acuity was -log mean angle of resolution (-logMAR) 0.91+/-0.53 (Snellen equivalent 20/160) yielding a utility value of 0.67. After suture removal and optical rehabilitation, binocular visual acuity increased to median -logMAR 0.36+/-0.36 (20/46) with a utility value of 0.79. Over the 10 years after surgery and considering graft survival and discounting, a cost utility of 9551 euros per QALY was gained (equivalent to US11,557 dollars). One-way sensitivity analysis yielded a range from 7706 euros to 12874 euros per QALY, highlighting the robustness of the model. CONCLUSIONS: Although an expensive procedure, PK is cost effective in patients with bilateral poor vision.
Monocular deprivation in an identical twin.
PURPOSE: The scientific literature contains minimal human studies of the effect of monocular deprivation on a single eye of twins. This report examines the effects of early visual deprivation on axial length measurements by comparing the refractive findings and axial length measurements of identical twins' 4 eyes, 1 visually deprived and 3 nondeprived. METHODS: A retrospective record review was performed on the medical records of identical 6-year-old Hispanic female twins. Both patients had received eye care at the University Optometric Center, State University of New York, for a period of at least 5 years. Subsequently, an Internal Review Board-approved prospective study was undertaken. Each twin received a comprehensive eye examination and an A-scan. RESULTS: The findings of the 3 nondeprived eyes were compared with those of the 1 deprived eye. The 3 nondeprived eyes had at least 20/20 visual acuity, low hyperopia or astigmatism, low with the rule keratometric findings, 12-mm corneal diameters, and A-scan results ranging from 21.0 to 21.55 mm. The remaining eye, which was visually deprived secondary to congenital cataract from birth to 6 months of age, had an aphakic refractive condition, decreased visual acuity, glaucoma, esotropia, and borderline microcornea. Keratometric findings were comparable with those of the other 3 eyes, whereas the A-scan finding was 25.16 mm. CONCLUSION: This case presented a unique opportunity to directly examine the effect of visual deprivation on axial elongation. Although other factors, such as glaucoma and borderline microcornea, may influence axial elongation, the findings in this patient indicate that a substantial portion, if not all, of the axial elongation can be attributed to early monocular deprivation.
The association between vision quality of life and academics as measured by the College of Optometrists in Vision Development Quality of Life questionnaire.
BACKGROUND: Undetected visual problems are one of the causes of academic difficulties in the classroom. An easily administered screening device that identifies children who are likely to do poorly in school because of vision problems would be a valuable tool. The screening should be able to be performed by a classroom teacher or aide. The objective of this study was to determine if there was an association between vision-related quality-of-life factors (19-item College of Optometrists in Vision Development Quality of Life [COVD-QOL] questionnaire checklist) and academic performance. A secondary objective was to determine whether student and parent responses to the questionnaire would be similar. METHODS: Ninety-one parents or guardians and their children, attending the third, fifth, and seventh grades in a public school participated in this study. Both the parent or guardian and student independently completed the checklist. The scores of both groups were compared with the Stanford IX test scores for total reading, total math, total spelling, and total battery scores of the Stanford IX. The parent or guardian and student scores were compared to evaluate the agreement (intergroup reliability). RESULTS: Parent or guardian and student checklist scores were compared. The Wilcoxon Signed Rank test showed that the mean scores for the parent or guardian were significantly lower than for third grade students and also for the total sample. Visual symptoms were found to be inversely correlated to academic performance; the lower the academic score, the more symptoms were reported. Symptoms reported by third grade students and their parents tended to be more highly correlated with academic scores. In general, symptoms reported by the parent were more highly correlated with academic score than the symptoms reported by the student. CONCLUSION: The COVD-QOL questionnaire is a cost-effective, quick, and easy tool that may be used in school screening to identify possible visual symptoms that are correlated to academic performance.
The Massachusetts preschool vision screening program.
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Associations of ambient illumination with mood: contribution of ophthalmic dysfunctions.
Evidence suggests that ocular pathology could reduce light-stimulated neuronal signaling to the suprachiasmatic nuclei. This study investigated associations of ambient illumination with moods, while considering the contribution of ophthalmic dysfunctions. Seventy Black (59%) and White (41%) Americans participated in the study. Their average age was 68.27+/-5.97 years; 73% were women. Baseline data included: physical health, mood, and sociodemographics. Ophthalmic factors including visual acuity, visual field defects, intraocular pressure, vertical and horizontal cup-to-disk ratios, and nerve-fiber-layer thickness were assessed at SUNY Downstate's eye clinic. The following week, participants wore the Actiwatch-L at home to monitor ambient illumination and sleep. Cosine analyses were performed on the logarithm of measured illumination, yielding the mesor and acrophase of daily illumination exposure. Sleep was estimated with an automatic scoring algorithm. Of the sample, 25% reported visual impairment and 85% reported good to excellent health; 27% were visually impaired according to American criteria. Partial correlation analyses showed an inverse correlation of daily illumination levels to depressed mood [r(p)=-0.33, P<0.05], when age, sex, ethnicity, income, BMI, diabetes, hypertension, respiratory disease, and habitual sleep duration were controlled. With further control for ophthalmic factors, the magnitude and significance of the correlation diminished [r(p)=-0.26, NS]. Individuals receiving daily illumination later in the day reported more depressed moods [r(p)=0.36, P<0.01]; of note, this correlation was not significant after control for the covariates [r(p)=0.18, NS]. Regression analysis indicated that the ophthalmic factors explained 13% of the variance in depression. Our results show that both the level and timing of ambient illumination are associated with mood. Furthermore, they suggest that visual impairment has a mediating effect on the associations of ambient illumination with depression, supporting the notion that ocular pathology lessens the efficacy of daily illumination in promoting positive moods.
Severe delirium due to basal forebrain vascular lesion and efficacy of donepezil.
A severe intractable delirium caused by the basal forebrain vascular lesion and its dramatic recovery after donepezil administration were reported. A 68-year-old man had suffered for a month from delirium of mixed type caused by the right basal forebrain vascular lesion after surgery for craniopharyngioma. Magnetic resonance imaging (MRI) showed hemorrhagic infarcts in the head of the right caudate nucleus and the right basal forebrain of the medial septal nucleus, diagonal band of Broca and nucleus basalis of Meynert. He had been treated with anti-psychotics, anti-depressants and hypnotics, which resulted in little improvement. Donepezil administration dramatically improved his intractable delirium at the 19th post-donepezil administration day, but this was followed by amnestic symptoms. Clinical correlates of delirium with the basal forebrain lesion and efficacy of donepezil support the hypocholinergic theory of delirium.
Visual function in epilepsy patients treated with initial valproate monotherapy.
PURPOSE: To investigate whether initial valproate (VPA) monotherapy for the treatment of epilepsy causes visual field defects and visual dysfunction. METHODS: In a cross-sectional study, visual fields were examined with the kinetic Goldmann and automated Humphrey perimeters, contrast sensitivity function with the Pelli-Robson letter chart and colour vision with the Standard Pseudoisochromatic Plates Part 2 (SPP 2) and Farnsworth-Munsell 100 Hue test (FM 100) in eighteen epilepsy patients (aged 18--50 years, 30.2.+/-10 years, mean+/-S.D.) treated with initial valproate monotherapy for 2--20 years (8.4+/-5.1 years). RESULTS: None had vigabatrin-type, concentric visual field defect with the kinetic Goldmann or automated Humphrey perimetries. In the Humphrey perimetry, the mean deviation for the group was within normal limits varying from -2.53 to 0.59 dB (-0.74+/-0.80 dB) in the right eye and from -2.66 to 0.67 dB (-0.78+/-0.82 dB) in the left eye. In the FM 100 test, acquired colour vision deficiency was found in two out of 18 patients (11%, 95% CI: 0--25%). However, the mean total error score was lower in the patient group than in the control group. All patients had normal contrast sensitivity function. CONCLUSIONS: The use of VPA in the treatment of epilepsy is not associated with visual field defects similar to vigabatrin, but may induce abnormalities in colour vision.
What do catastrophic visual binding failures look like?
Ordinary vision is considered a binding success: all the pieces and aspects of an image are bound together, despite being processed by many different neurons in several different cortical areas. How this is accomplished is a key problem in visual neuroscience. The study of visual binding might be facilitated if we had ways to induce binding failures. A particularly interesting failure would involve a loss of the physical integrity of the image. Here, we identify conditions that induce such perceptual failures (e.g. the melting together of equiluminant colored images and the fragmentation of retinally stabilized images) and we suggest that these should studied using electrophysiological measures of binding.
Low contrast vision function predicts subsequent acuity loss in an aged population: the SKI study.
Can vision tests predict subsequent loss of acuity? The association between performance on several low contrast spatial vision measures, glare recovery, color discrimination, flicker sensitivity, stereopsis and ocular disease status at baseline and acuity loss 4.4 years later was examined in a large aged random sample with good initial acuity. In univariate analyses, several vision measures, retinal disease status and age were each significant predictors of subsequent acuity loss. In a multiple regression analysis, only low contrast spatial vision was a significant predictor, but the other vision measures, retinal disease status and age were not. For each doubling of low contrast spatial vision threshold at baseline, individuals were more than two times as likely to suffer subsequent significant visual acuity loss. Tests of low contrast spatial vision are strong predictors of significant subsequent visual acuity loss. These findings have implications for clinical trials, clinical management, and acceptance of these measures into clinical practice.
Results from screening over 9000 mutation-bearing mice for defects in the electroretinogram and appearance of the fundus.
Random mutagenesis combined with phenotypic screening using carefully crafted functional tests has successfully led to the discovery of genes that are essential for a number of functions. This approach does not require prior knowledge of the identity of the genes that are involved and is a way to ascribe function to the nearly 6000 genes for which knowledge of the DNA sequence has been inadequate to determine the function of the gene product. In an effort to identify genes involved in the visual system via this approach, we have tested over 9000 first and third generation offspring of mice treated with the mutagen N-ethyl-N-nitrosourea (ENU) for visual defects, as evidenced by abnormalities in the electroretinogram and appearance of the fundus. We identified 61 putative mutations with this procedure and outline the steps needed to identify the affected genes.
Optic-flow and egocentric-direction strategies in walking: central vs peripheral visual field.
The impact of a central or peripheral visual field loss on the vision strategy used to guide walking was determined by measuring walking paths of visually impaired participants. An immersive virtual environment was used to dissociate the expected paths of the optic-flow and egocentric-direction strategies by offsetting the walker's point of view from the actual direction of walking. Environments consisted of a goal within a forest, the goal alone, or the forest alone following a brief presentation of the goal. The first two environments allowed an evaluation of the visual information used in a goal-directed task whereas the third environment investigated the information used in a memory-guided task. Participants had either a central (CFL) or peripheral visual field loss (PFL) or were fully sighted (FS). Results showed that, for the goal-directed task, the CFL group was less influenced by optic flow than was an age-matched FS group. Optic flow decreased heading error by only 1.3 degrees (16%) in the CFL group compared to 3.6 degrees (42%) in the FS group. The PFL group showed an optic-flow influence (2.4 degrees or 26%) comparable to an older, age-matched FS group (2.9 degrees or 31%). For the memory-guided task, all but the PFL group had heading errors comparable to those obtained in the goal-alone scene, demonstrating the ability to use an egocentric-direction strategy with a stored representation of either the goal's position or an offset relative to a landmark instead of a visible goal. The paths of the PFL group veered significantly from the predicted paths of both the optic-flow and egocentric-direction strategies. The findings of this study suggest that central vision is important for using optic flow to guide walking, whereas peripheral vision is important for establishing and/or updating an accurate representation of spatial structure for navigation.
Characterisation of ocular fixation in humans by analysis of saccadic intrusions and fixation periods: a pragmatic approach.
Eye movements during fixation were recorded in 55 normal subjects with ages ranging from 21 to 81 years. We analysed ocular fixation recordings using measurements of saccadic intrusion amplitudes and frequencies along with fixation periods and mean fixation displacement. Viewing conditions included monocular, binocular and presence or absence of a visual fixation target. Visual feedback reduced the saccadic intrusion amplitudes but had no effect on fixation periods or mean fixation displacements. Binocular viewing had no effect on saccadic intrusion amplitudes, fixation periods or mean fixation displacements. A decrease in fixation periods and an increase in the number of saccadic intrusions with age was observed. This approach could be a clinically useful tool to quantify ocular fixation in neurological disease.