Use Of Spectacles Research Articles

The Visual Status of Older Persons Residing in Nursing Homes

To characterize habitual visual acuity, contrast sensitivity, spectacle use, and eye care utilization in a large sample of older adults residing in nursing homes. Of 33 nursing homes identified in Birmingham, Alabama, 17 served as sites. Eligibility criteria included age 55 years or older, English-speaking, and Mini-Mental State Examination score of 13 or higher. Habitual distance and near visual acuity and contrast sensitivity were measured for each eye and binocularly. Residents and a family member/guardian were interviewed about spectacle use and eye care utilization. Medical records provided information on demographics, chronic medical conditions, date of last eye examination, duration of residence in the nursing home, and health insurance. Of 380 enrollees, 57% had distance visual acuity in the better eye worse than 20/40; 10% had visual acuity of 20/200 or worse. Near visual acuity was slightly worse on average by a line than distance acuity. Three-fourths of residents had abnormal binocular contrast sensitivity. The medical record had no record of or reference to an eye examination for 66% of enrollees despite 90% having health insurance. The high rate of visual impairment in nursing homes underscores the need to understand its causes and to evaluate interventions to address this public health challenge.

Hyoscine skin patches for drooling dilate pupils and impair accommodation: spectacle correction for photophobia and blurred vision may be warranted

Hyoscine skin patches diminish salivation by their anticholinergic action. The aim of reporting this case series is to present the ophthalmic side effects in children, and to highlight the precautions to take. Five children (two males, three females; age range 8-18y) with quadraplegic cerebral palsy (Gross Motor Function Classification System Level V) and profound intellectual impairment, wearing hyoscine skin patches to control excessive salivation, were examined. Binocular visual acuity, pupil reaction, pupil diameter, and dynamic retinoscopy were recorded before and after instilling guttae cyclopentolate 1%. The accommodative responses were compared with the expected norms. Spectacle correction was provided for refractive error and to compensate for lack of accommodation. Tinted lenses were provided for photophobia. Visual assessment was repeated 6 months later. All children had dilated pupils with a mean diameter of 7.8mm (range 7-9mm) before instilling guttae cyclopentolate. Mean pupil constriction to bright light was only 1.8mm (range 1-2mm). Mean resting accommodation was 0.45 dioptres (D; range 0-1D) and no accommodative responses were detected on dynamic retinoscopy. Three children were photophobic. Visual behaviour was seen to improve after the use of appropriate spectacles. Photophobia was relieved by tinted lenses. The anticholinergic effects of hyoscine skin patches can cause photophobia and impair vision due to pupil dilatation and paralysis of accommodation. Appropriate spectacles are recommended.

056 Qualité optique subjective et inutilité de verres correcteurs avec un implant difractif multifocal apodisé

Apodized diffractive multifocal IOLs provide a new surgical concept to treat presbyopia in the cataract patient. The effectiveness in spectacle independency, pre- and postoperative optical quality and discomfort provoked by different optical phenomena were evaluated in this prospective study. 30 patients underwent bilateral standard phacoemulsification and implantation of a Restor® MIOL. The patients’ postoperative distance and near visual acuity and the use of spectacles were documented A standardized questionnaire was designed to rate the subjective quality of vision and the main visual disturbances as glare, blurred vision, starbursts, halo and ghost images preoperatively and one month postoperatively. The patients were asked to mark the degree of visual disturbances on a scale from 0 (absence) to 100 (worst disturbances) at photopic, mesopic and scotopic illumination. Postoperative spherical equivalent was 0.11±0.78D. Uncorrected far and near visual acuity were 0.71±0.18 and 0.90±0.31, respectively. Best-corrected far visual acuity was 0.92±0.16. Postoperatively, 4 patients depended on spectacles and 2 patients used spectacles for reading. The overall score of the questionnaire improved postoperatively. There was impairment in photopic and improvement in scotopic visual disturbances as well as in the judgments of the overall optical quality. The preoperatively predominant visual disturbance was glare, which changed to blurred vision and halos postoperatively. Halos were predominant postoperatively at scotopic conditions, but not at photopic or mesopic illumination. With MIOLs starbursts and halos worsened at scotopic illumination. After MIOL implantation a good visual acuity and reading ability can be reestablished. Over 90% of the patients were independent from spectacles. Although the apodized diffractive optic minimized the overall optical disturbances and the overall visual quality improved some visual disturbances worsened with MIOL-implantation.

Exzessives Tränen bei Gleitsichtglasfehlzentrierung

The eye and the progressive lenses in eyeglasses form a three-dimensional optical system, which must be well matched. A 71-year-old man complained about a new and unusual tearing and scratching sensation in his eyes. The work-up revealed subnormal values of the Schirmer test, from the eye refraction of different eyeglass powers and strongly decentred progressive lenses in his, just a few-months-old, eyeglasses. A lubricating therapy remained without success. However, the use of new and correct eyeglasses eliminated the symptoms. Tearing and the sensation of scratching in the eyes in this case are symptoms of an eyeglasses-induced asthenopia. Consequently, it may pay to control the eyeglasses and the centration of progressive lenses in cases with unclear, unspecific eye symptoms even without dissatisfaction with eyeglasses.

This issue of Acta

This issue of Acta emphasizes retinal disease, with a particular focus on the development of new treatment modalities. Two editorials − by Morten la Cour and Anders Kvanta, respectively − deal with emerging new treatments. Our review article is a critical appraisal of new therapies for neovascular age-related macular degeneration and is written by Italian and American ophthalmologists. The cover figure shows a magnetic resonance image of a large inclusion cyst in the orbit (see Hussin et al.). Martin Vinten and colleagues, in Copenhagen, report that intravitreal triamcinolone constricts the retinal blood vessels. This pharmacological effect of triamcinolone may be important in its mechanism of action in diabetic macular oedema and other diseases. Ålborg's Knudsen documents the thickness of the macular region in normal subjects and those with diabetes with and without macular oedema and demonstrates that thickness measurements can indeed be used to diagnose diffuse macular oedema. Neubauer et al., based in Munich and Thessaloniki, describe findings of a correlation between fluorescein leakage and retinal thickening on optical coherence tomography in patients with diabetic macular oedema. Eydís Ólafsdottir and associates, in Iceland and Sweden, report on the diabetes population in the Laxå community in Sweden, where screening for both diabetes mellitus and diabetic eye disease has created an optimal situation for the prevention of diabetic blindness. Helsinki's Sirpa Loukovaara et al. continue their study on diabetic retinopathy in pregnancy and find that progression of retinopathy is associated with a low concentration of glycodelin, a glycoprotein secreted from endometrial glands and involved with the immune response. Parodi et al., Trieste, describe atrophic changes in the retinal pigment epithelium following photodynamic therapy in myopic individuals. Osaka-based Arimura et al. have developed novel charts to evaluate metamorphopsia and claim to be able to quantify metamorphopsia in patients with macular hole. The letters to the editor include a description from German authors Spandau et al. of the use of intravitreal bevacizumab (Avastin®) for branch retinal vein occlusion and age-related macular degeneration. Meanwhile, Kernt et al., Munich, find intravitreal bevacizumab to be safe in terms of intraocular and blood pressure. Writing from Odense, Pedersen et al. report a case of choroidal metastasis in multiple endocrine neoplasia. Helsinki-based Raivio et al. used transscleral cyclocoagulation combined with anterior retinal cryocoagulation in patients with neovascular glaucoma with good results. Bjärnhall et al., in Uppsala and Hiroshima, measured the mean transit time of fluorescein in the retinal circulation of patients with primary open-angle glaucoma and normal-tension glaucoma. They report findings of a correlation between neuronal atrophy and circulation that was similar in both types of glaucoma. Spanish authors Ferreras et al. continue the search for the optimum diagnostic criteria in glaucoma and suggest that frequency doubling perimetry may be helpful. Ozturk et al., writing from Turkey, report their findings that brimatoprost and Cosopt® are similar in their ability to lower intraocular pressure and both are well tolerated. Thomas Olsen, in Århus, finds that the optical coherence interferometry of the Zeiss IOLMaster increases the accuracy of intraocular lens (IOL) power calculations. Budapest's Kovács et al. deal with IOL power calculation in combined cataract and vitreous operations and point out that macular thickness must be taken into account in preoperative calculations. Langenbucher et al., of Erlangen-Nürnberg, may provide more mathematics than most readers of Acta enjoy, but present a comprehensive calculation scheme for retinal image size after implantation of toric (IOLs). Japanese authors Miyata et al. suggest that sharp IOL edges are required to prevent posterior capsular opacification and do not induce anterior capsular contraction. Writing from Sweden, Fagerholm et al. describe a new type of corneal opacities in a small Swedish family. Fernández de Castro and associates, South Carolina, USA, report that ocular wavefront aberrations vary greatly from subject to subject and treatment must be carefully individualized. Denmark-based Sirbikaite and Ehlers' letter to the editor points out the usefulness of Lacrytest® for semiquantitative diagnosis of ocular allergens. Ziylan et al., in Turkey, highlight the risk of isoamitropic amblyopia in highly hyperopic children and describe the use of spectacles for treatment. Lübeck's von Buelow et al. describe a case of systemic bevacizumab (Avastin®) treatment for a retinal haemangioma.

Can Information on the Purpose of Spectacle Use and Age at First Use Predict Refractive Error Type?

Purpose: To assess the sensitivity and specificity of predicting refractive error type using information from a four-item questionnaire on the purpose of spectacle use and age at first use. Methods: The Sydney Myopia Study examined 1,740 year 1 (78.9% response) and 2,353 year 7 students (75.3% response) from a random cluster sample of 34 primary and 21 secondary schools across Sydney. Parents of participants completed a four-item questionnaire that sought data on parental spectacle use, age at first use, and purpose of use (for clear distant vision, close work, or both). Prescriptions were obtained for 720 of 3,209 (22%) parents (73% of those approached) for validation. A receiver operating characteristic (ROC) curve was used to determine the optimal cutoff age for spectacle use in myopia classification. Results: Using the ROC curve, a cutoff age of 30 years at first spectacle use produced the highest accuracy in determining myopia. We combined information on the purpose for using spectacles (for distant and near vision) and age of first use at 30 years or younger to determine myopia, otherwise hyperopia. Validated against prescriptions, the sensitivity and specificity of these predictions were 0.89 and 0.83, respectively, for myopia. The specificity was 0.92 for hyperopia and 0.80 for astigmatism, though corresponding sensitivities were lower at 0.23 and 0.46, respectively. Conclusions: In a sample of the parents of Sydney Myopia Study participants, information on the purpose of spectacle use with an age-at-first-use criterion can identify myopic refractive error with reasonable sensitivity and specificity. This four-item questionnaire may assist future epidemiological studies of screening for myopia.

Sleep Disturbances and Falls in Older People

Sleep disturbances are common in older people and may contribute to risk of falling. Cross-sectional studies were performed in hostels and with an Internet-based survey. Questionnaires on falls and sleep disturbances were undertaken with clinical measures of cognition, mobility, blood pressure, and vision in the participants in hostels. There were 150 participants in hostels (mean age 81 +/- 8 years) and 150 respondents to the Internet survey (mean age 70 +/- 5 years). Sleep disturbances were reported by most participants in both the hostel and Internet studies. In hostel participants, falls were associated with poor sleep quality (odds ratio = 4.5, 95% confidence interval, 1.9-12.2; p =.002) and number of nocturnal awakenings (2.5 +/- 1.5 vs 2.0 +/- 1.4, p =.04). Other risk factors for falls in these persons included Geriatric Depression Scale score, pain, Timed Get Up and Go Test score, and the use of diuretics. In the Internet respondents, risk factors for falls included poor health rating and the use of spectacles, bifocals, and walking aids; fewer falls were reported by those participants without any sleep disturbances. Sleep disturbances are common in older people and are associated with their risk of falling. Internet-based surveys may be a useful adjunct method for research in older people.

Prevalence of refractive error and attitude to spectacle use among drivers of public institutions in Ibadan, Nigeria

High rate of motor vehicle accidents' have been associated with poor vision. Studies on drivers from elsewhere other than health institutions have found abnormal visual acuities. The aim of this study is to determine prevalence of refractive errors and the attitude to spectacle wear among drivers of public institutions studied. A cross sectional population study of all 99 motor vehicle drivers from the College of Medicine, University of Ibadan and University College Hospital (UCH) Ibadan between December 2003 and January 2004. The ninety-nine motor vehicle drivers in the study comprised of 67 (67.7%) from the College of Medicine, and 32 (32.3%) from the UCH. All were males, aged 38 to 60 years, mean 50.1 +/- (SD= 4.8 years). Proportion of drivers with refractive errors was 16.7% (95% CI, 16.6-16.8) but only 56.3% of these wear glasses while driving (others did not including 3 out 4 who were bilaterally visually impaired without glasses). Relative frequency of RTA among drivers was 16.2%, the risk was marginally higher among drivers with refractive error (OR 1.2, 95% CI: 0.4-3.7). The commonest refractive error was simple hypermetropia present in 15 eyes. Hypermetropia was associated with increasing age of drivers (p<0.05). Majority (97.7%) of the drivers were presbyopic but only 32 (32.3%) were current wearers of spectacles. Refractive errors were present in 16.7% of drivers studied. But 43.8% of these (3 out 4 of whom were bilaterally visually impaired without glasses) do not wear corrective lenses while driving. There is need for periodic visual screening exercise and eye health education on drivers.

Refractive Surgery in Children: Is it Ready for Prime Time?

IntroductionPotential indications for excimer laser procedures in children include accommodative esotropia, bilateral high ametropia, and severe anisometropia. Treatment of these conditions has traditionally included spectacle or contact lens use. This treatment, however, is often ineffective in children with severe anisometropia or bilateral ametropia, especially those with neuropsychological disorders. Refractive surgery may be a viable treatment option for these conditions.MethodsThe visual and refractive results from our studies on photorefractive keratectomy for pediatric anisometropic amblyopia are discussed. Also, I will present a review of the world literature on excimer laser procedures for accommodative esotropia, pediatric high anisometropia, and pediatric bilateral high ametropia.ResultsIn our study, at 36 months follow-up, 7 of 9 patients who were able to perform psychophysical acuity testing preoperatively had improvement of two or more lines of uncorrected visual acuity and 6 of 9 had improvement of two or more lines of best corrected visual acuity. Fifty percent of the myopic patients and 100% of the hyperopic patients were within 2 D of refractive target at the 36-month follow-up visit. Refractive error stability has been good and corneal haze has been minimal.ConclusionsRefractive surgery in children to reduce amblyopiogenic levels of refractive error is proving to be relatively stable. Best corrected and uncorrected visual acuity has also been shown to improve following the excimer laser procedures. Refractive surgery also appears to be effective for pure accommodative esotropia. Randomized clinical trials are needed to fully establish safety and efficacy. Other refractive procedures, such as clear lens extraction and phakic intraocular lenses, may also prove to be valid treatment options for these conditions in the future.

Refractive Error and Patterns of Spectacle Use in 12-Year-Old Australian Children

To document the prevalence of visual impairment resulting from refractive error and to describe patterns of spectacle use in a representative sample of 12-year-old Australian school children. Population-based cross-sectional study. Two thousand three hundred fifty-three predominantly 12-year-old children examined from 2004 through 2005. Logarithm of the minimum angle of resolution (logMAR) visual acuity (VA) was measured unaided and with spectacles if worn. Subjective refraction, cycloplegic autorefraction (with cyclopentolate), and detailed dilated fundus examination were performed. Myopia was defined as spherical equivalent (SE) refraction < or =-0.50 diopters (D), hyperopia as SE refraction > or =2.0 D, and astigmatism as cylinder > or =1.0 D. Uncorrected visual impairment was defined using unaided VA, and presenting visual impairment was defined using spectacle-corrected VA, if worn. Visual impairment was defined as VA <20/40 (<40 logMAR letters) for both better and worse eyes. Spectacle need was defined as uncorrected visual impairment in the better eye, improving by at least 2 lines with refraction, and undercorrection as presenting impairment in the better eye, improving by at least 2 lines with refraction. Uncorrected and presenting visual impairment in at least 1 eye because of refractive error was found in 10.4% and 3.7%, respectively. Spectacle use was reported by 448 children (19.0%); 204 (46.3%) had myopia, 48 (10.9%) had hyperopia, and 96 (21.8%) had astigmatism in at least 1 eye; 38.3% had no significant refractive error in either eye. Eight children were in need of spectacles and 37 children (8.3% of spectacle users) were undercorrected. Nonrefractive spectacle users were more likely to report eyestrain and headache or to have had learning difficulty at school (P<0.0001). This study documents a relatively low prevalence of undercorrected refractive error in a population of Australian children. Nonrefractive prescription of spectacles is common.

The Correlation Between Migraine Headache and Refractive Errors

A literature review reveals historical references to an association between migraine headache and refractive errors, but a lack of scientific evidence relating to these claims. In a masked case-controlled study, we investigated the four aspects of refractive errors that have been implicated in the literature as correlated with migraine: spherical refractive error, astigmatic refractive error, anisometropia, and uncorrected ametropia. We also compared the calculated scalar value of refractive error, aided and unaided visual acuity, and spectacle use in migraine and control groups. We then investigated the relationship between refractive components and key migraine headache variables. Compared with the control group, the migraine group had higher degrees of astigmatic components of refractive error assessed both objectively (C, p = 0.01; C(0), p = 0.01; C(45), p = 0.05) and subjectively (C, p = 0.03; C(0), p = 0.03; C(45), p = 0.05), uncorrected astigmatic components of refractive error (C(0), p = 0.02; C(45), p = 0.04), and anisometropia (p = 0.06). Perhaps the historical literature is indeed correct that low degrees of astigmatism and anisometropia are relevant in migraine. Our most significant finding was of higher degrees of astigmatism in the migraine group. This study does indicate that people who experience migraine headaches should attend their optometrist regularly to ensure that their refractive errors are appropriately corrected.

Neuro-Ophthalmic Manifestations of Intracranial Cavernous Hemangiomas

To describe the neuro-ophthalmic manifestations of patients with intracranial cavernous hemangiomas (cavernomas). A retrospective review of all patients with intracranial cavernomas with neuroophthalmic manifestations who were treated at the Royal Adelaide Hospital in Australia between 1994 and 2004. There were nine patients (three men and six women), with a mean age of 39 years (range 22-61). There was one cerebellar lesion, two thalamic, four pontine, one midbrain/pontine, and one midbrain. Ophthalmic presentations included internuclear ophthalmoplegia (one patient), third cranial nerve (CN) palsy (one patient), fourth CN palsy (one patient), and sixth CN palsy (six patients). Three patients underwent extraocular muscle surgery, and six were treated medically or observed. In five patients the diplopia resolved, in three it was only mild, and in one patient no significant change was noted during the follow-up period. Diplopia is the main neuro-ophthalmic manifestation of intracranial cavernomas. Sixth CN palsy is the most common cause. Neurosurgical or conservative treatment leads to improvement in most cases, and later use of spectacles or extraocular muscle surgery may lead to further improvement.

Patterns of Spectacle Use in Young Australian School Children: Findings from a Population-Based Study

To describe the patterns of spectacle use in a population-based sample of Australian Year 1 school children (mostly aged 6 years). Logarithm of the minimum angle of resolution (logMAR) visual acuity was measured in both eyes before and after pinhole correction, and using spectacles if worn. Cycloplegic autorefraction (cyclopentolate) and detailed dilated fundus examination were performed. Visual impairment was defined as visual acuity <40 logMAR letters (ie, <20/40 Snellen equivalent). Myopia was defined as spherical equivalent (SE) refraction < or = -0.50 diopters (D), and hyperopia as SE refraction > or = +2.0D, deemed significant when > or = +3.0D. Astigmatism was defined as cylinder > or =1.0D and anisometropia as SE refraction difference between the two eyes at least 1.0D. One thousand seven hundred forty predominantly 6-year-old school children were examined during 2003 to 2004. Spectacle use was documented in 77 children (4.4% of sample). Uncorrected visual impairment was found in the worse eye of 71 children (4.1%) and refractive error accounted for the majority (69.0%). Astigmatism was the most common refractive error causing visual impairment, accounting for 46.5%. Hyperopia, with or without astigmatism, was the most frequent reason for spectacle use, documented in 40.3%. Spectacle use in the absence of significant refractive error, amblyogenic risk factors, or visual impairment was noted in 26 children (33.8% of spectacle wearers). The prescription of spectacles could have benefited a further 26 children (1.5% of sample), mostly for correction of astigmatism. This study documents a significant disparity between spectacle use and need. Astigmatism was the most common cause of visual impairment due to refractive error.

Changes in the Spatial-Contrast Sensitivity during Work with Liquid-Crystal Monitors and with Spectral Correction of Vision

Thirty-seven design engineers with refraction varying from emmetropia to −6.0-diopter myopia and 5.5-diopter hypermetropia and visual acuity 1.0 (with correction) were examined for the spatial-contrast sensitivity (SCS) of the organ of vision before and after working for 4 h with a liquid-crystal monitor under ordinary conditions and with the use of LS-KOM spectacles having a special light-absorbing (spectral) layer. After 4 h of working under ordinary conditions, a significant decrease in SCS for high frequencies and a slight decrease for medium frequencies were observed. When the LS-KOM spectacles were used, the SCS increased at all frequencies at the beginning of work and was retained at the baseline normal level after 4 h of work, being higher than that after working without the light-absorbing spectacles. It was established that long-term work with an LCD monitor interferes with the perception of high spatial frequencies, while the use of the LS-KOM spectacles increases the SCS and allows its normal level to be maintained during 4 h of work.

In focus: the use of bifocal spectacles with children with Down's syndrome

Over 75% of children with Down's syndrome fail to accommodate accurately on near targets. This deficit must result in optically blurred images for near work. This present study set out to evaluate the controlled use of bifocal spectacles as an aid to near focusing. Although sometimes used clinically, no systematic studies of bifocals for children with Down's syndrome have been reported. This was a comparative non-randomised interventional study. Thirty-four children with Down's syndrome of primary school age (5-11 years) took part, assigned in equal numbers to form two matched groups. All children received a full optometric assessment prior to entering the study. The treatment group was prescribed bifocal spectacles with a +2.50 addition, and the control group provided with single vision lenses to correct any clinically significant refractive error. Three follow-up visits were made over a 5-month period after spectacle provision. The treatment group showed consistently more accurate accommodation than the control group both through the bifocal segment, and, unexpectedly, through the distance part of the lens (p < 0.05). Compliance with new spectacles was high in both groups (>82% fully compliant). Bifocals confer benefit to children with Down's syndrome who under-accommodate, both directly (better focusing through the bifocal) and indirectly (by encouraging improved accommodation through the distance part of the lens). Based on the results of this study, eye examinations of children with Down's syndrome should routinely include a measure of accommodation at near, and bifocal spectacles should be considered for those who show under-accommodation.

Use of Recommended Eye Glasses by Professional Librarians

The study attempted to investigate why professional librarians wear eyeglasses, whether they have enough information concerning the use of eyeglasses, whether the use of eye glasses improves their productivity, and if the use of eyeglasses can be regarded as an occupationally-induced health problem. Two hundred five of the librarians who attended the 2004 Annual General Conference of Nigerian Library Association Meeting were studied. A stratified random sampling technique was used to select the respondents. A questionnaire was used to elicit information from them. The study revealed that librarians use eyeglasses because of eyestrain. It was found that wearing eyeglasses improve librarians' productivity and efficiency. It was concluded that librarians wear eyeglasses not for fashion, but to correct poor reading vision. It is suggested that eye health education and information be widely disseminated. Librarians should go for regular eye check ups and reduce stress on the eye by alternating reading with writing.

Falls and fractures in women at work

Older women have been observed to have more serious injury particularly fractures after slips, trips or falls at the workplace. It is unclear whether this excess reflects a greater likelihood of falling or a greater proportion presenting with fractures once the fall has occurred. Two studies were carried out: Study A, of 130 women who fell at work and matched referents, and Study B, of 120 women who fell at work and sustained a major fracture and 314 matched referents who fell but for whom no fracture was recorded. In Study A, the workplace of the case and referent was observed, questionnaires completed and objective health measures carried out. Study B relied on information obtained from the subject by postal questionnaire. Women who fell were older than referents matched on workplace and occupation, but age did not continue to be a significant factor after allowing for bodyweight and use of spectacles. Fractures were more common in older women who fell, particularly post-menopausal women with low body mass. The risk of fracture increased steadily with age without an obvious discontinuity around the likely age of menopause. The observed excess of fractures in older women falling at work appeared to be explained by the greater risk of fracture among those who fell.

Need and Challenges of Refractive Correction in Urban Chinese School Children

Uncorrected refractive error is recognized as the principal cause of visual impairment in school-aged children. Although correction of refractive error is easy, safe, and effective, many children are without the necessary spectacles. Empiric research on barriers to refractive correction remains limited, precluding the formulation of effective remedial actions. The aims of this study were to characterize parental awareness and other barriers to spectacle use among children considered to be in need of refractive correction and to determine the proportion undercorrected for those already with spectacles. A population-based sample of children 5 to 15 years of age was examined in Guangzhou, China. Visual acuity was measured followed by cycloplegic refraction and best-corrected vision. Parental awareness of the child's vision difficulties, spectacle use, and frequency of vision checkups were collected by questionnaire. Associations between these variables and demographic and socioeconomic characteristics were investigated with multiple logistic regression. Among the 4359 examined children, 919 (21.1%) were found to be in need of refractive correction. Need was defined as uncorrected visual acuity < or = 0.50 in both eyes correctable by at least two lines in the better eye. Parental awareness was apparent for 85% of cases; 74% had spectacles. Awareness of vision difficulties was associated with older child age, greater visual impairment, and higher parental education. The purchase of spectacles was associated with greater visual impairment; the child's age, gender, parental education, and family income were not significant factors. Undercorrection by two lines or more in the better eye was found in 30% of those already with spectacles; undercorrection was associated with greater visual impairment and less frequent refraction checkups. Half of the children in need of first-time or updated spectacles are without them, an unacceptably high proportion. Younger children with moderate visual impairment are at particular risk for uncorrected refractive error. Parental education and enhanced school-based screening programs may be necessary to address the unfilled need for refractive correction among school-aged children.

The eye care profile and outcomes of multi-handicapped adults residing in Wayne County, Michigan group homes

Patients with multi-handicaps present clinical challenges and are underserved. Central nervous system dysfunction and ocular disorders with this population are prevalent and well-documented. However, vision care outcomes data are limited and specific visual function recommendations to caregivers are rarely cited. The charts of 110 multiply handicapped adults residing in 22 group homes in Wayne County. Michigan were retrospectively studied to identify ocular profiles and predictors of visual function. Sixty-five percent of the subjects were male and 80% were ages 26 to 55 years. There was no expressive language in 41%, and 37% were non-ambulatory. The median visual impairment level was moderate in both eyes (based on WHO). Significant associations between visual impairment level and subpopulations (such as seizure disorder, mental retardation without specific etiology, cerebral palsy, and Down syndrome) were identified. Successful spectacle wear statistically increased with higher refractive errors. Associations between cataract, nystagmus, and strabismus with particular subpopulations were significant (all P values < 0.0182). Clinicians who evaluate patients with multi-handicaps have few known predictors of treatment success. This study indicates that useful predictors of visual function can be made from refractive error, systemic conditions, and ocular diagnoses. No significant relationship was found with cognitive level and either vision impairment or spectacle use. The authors attribute successful implementation of recommendations to communication with group home caregivers.

A non-contact device for tracking gaze in a human computer interface

This paper presents a novel design for a non-contact eye detection and gaze tracking device. It uses two cameras to maintain real-time tracking of a person’s eye in the presence of head motion. Image analysis techniques are used to obtain accurate locations of the pupil and corneal reflections. All the computations are performed in software and the device only requires simple, compact optics and electronics attached to the user’s computer. Three methods of estimating the user’s point of gaze on a computer monitor are evaluated. The camera motion system is capable of tracking the user’s eye in real-time (9 fps) in the presence of natural head movements as fast as 100°/s horizontally and 77°/s vertically. Experiments using synthetic images have shown its ability to track the location of the eye in an image to within 0.758 pixels horizontally and 0.492 pixels vertically. The system has also been tested with users with different eye colors and shapes, different ambient lighting conditions and the use of eyeglasses. A gaze accuracy of 2.9° was observed.