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PubMed1995

The utility of three predictors of childhood myopia: a Bayesian analysis.

Any treatment to prevent the onset of juvenile myopia will require predictive tests in order to determine which children should receive treatment. Three risk factors for myopia were evaluated for their ability to predict myopia: (a) refraction at school entry; (b) refraction in infancy; and (c) parental history of myopia. Bayes' theorem was used to estimate these conditional probabilities. Refraction at school entry had twice the power to predict myopia (probability of juvenile myopia given the child is near emmetropia at school entry = 0.53) compared to either infant refraction (0.21-0.28) or parental myopia (0.20-0.25). While a history of any parent having myopia had the highest test sensitivity (probability of a positive family history of myopia given juvenile myopia in the child = 0.90) and refraction at school entry the highest test specificity (probability of more hyperopia than +0.50 D at school entry given no juvenile myopia = 0.91), none of these three factors had high values for both sensitivity and specificity. Further work is required to develop a battery of tests which could predict the onset of juvenile myopia with both adequate sensitivity and specificity.

Age Factors↗
PubMedDate not supplied

Prevalence of eye disorders among the elderly in Los Angeles.

A series of 431 vision screening records of seniors 55 years of age and older were analysed. Patients were examined by the UCLA Mobile Eye Clinic at two senior centers in the Los Angeles area, between the years 1982 and 1990. Sixty-eight percent of patients were females and 32% were males. The mean (+/-S.D.) age was 69 (+/-7.5) years. Common diagnoses were refractive errors (65.2%) and impaired visual acuity (37.0%). The prevalences of refractive errors were: hyperopia, 24.8%; myopia, 10.4%; presbyopia, 54.1%; and astigmatism, 31.8%. In most patients (94.0%), impaired visual acuity was corrected by spectacles. The prevalence of cataract was 29.5% and age-specific prevalences of cataract increased with age. The prevalences of other eye disorders were as follows: glaucoma, 6.3%; diabetic retinopathy, 1.2%; and macular degeneration, 5.1%. This study highlights the degree of ophthalmic disorders identified by vision screenings in the elderly population in senior centers; our results are consistent with previously reported studies of eye diseases in the elderly.

Journal Article↗
PubMed1989

Assignment of the gene for complete X-linked congenital stationary night blindness (CSNB1) to Xp11.3.

X-linked congenital stationary night blindness (CSNB) is a nonprogressive retinal disorder characterized by a presumptive defect of neurotransmission between the photoreceptor and bipolar cells. Carriers are not clinically detectable. A new classification for CSNB includes a complete type, which lacks rod function by electroretinography and dark adaptometry, and an incomplete type, which shows some rod function on scotopic testing. The refraction in the complete CSNB patients ranges from mild to severe myopia; the incomplete ranges from moderate hyperopia to moderate myopia. To map the gene responsible for this disease, we studied eight multigeneration families, seven with complete CSNB (CSNB1) and one with incomplete CSNB, by linkage analysis using 17 polymorphic X-chromosome markers. We found tight genetic linkage between CSNB1 and an Xp11.3 DNA polymorphic site, DXS7, in seven families with CSNB1 (LOD 7.35 at theta = 0). No recombinations to CSNB1 were found with marker loci DXS7 and DXS14. The result with DXS14 may be due to the small number of scored meioses (10). No linkage could be shown with Xq loci PGK, DXYS1, DXS52, and DXS15. Pairwise linkage analysis maps the gene for CSNB1 at Xp11.3 and suggests that the CSNB1 locus is distal to another Xp11 marker, TIMP, and proximal to the OTC locus. Five-point analysis on the eight families supported the order DXS7-CSNB1-TIMP-DXS225-DXS14. The odds in favor of this order were 9863:1. Removal of the family with incomplete CSNB (F21) revealed two most favored orders, DXS7-CSNB1-TIMP-DXS255-DXS14 and CSNB1-DXS7-TIMP-DXS255-DXS14. Heterogeneity testing using the CSNB1-M27 beta and CSNB1-TIMP linkage data (DXS7 was not informative in F21) was not significant to support evidence of genetic heterogeneity (P = 0.155 and 0.160, respectively).

Alleles↗
PubMed2006

The effect of axial length on photodynamic therapy.

PURPOSE: To determine the effect of the axial length of the eye on photodynamic therapy (PDT) light fluence. DESIGN: Laboratory investigation. METHODS: A calibrated Gullstrand-type model eye was used for this study. The axial length of the model eye was set to different values ranging from 20 to 31 mm, and the light fluence rate for treating a spot of 4 mm was recorded and compared with a fluence rate of 600 mW/cm2 with four indirect condensing laser lenses. RESULTS: The axial length of the eye is inversely related to light fluence. From myopia to hyperopia, the total deviation from 600 mW/cm2 was -37.7% to +53.8% (Mainster Standard; Ocular Instruments Inc, Bellevue, Washington, USA), and -48.3% to +20.5% (Mainster Wide Field; Ocular Instruments Inc), -52.3% to +16.7% (Volk Transequator; Volk Optical Inc, Mentor, Ohio, USA), and -52.3% to +15.3% (Volk PDT Laser; Volk Optical Inc). CONCLUSIONS: Axial length of the eye has a considerable effect on PDT light fluence rate in this model. These findings may be important for optimizing PDT, particularly in eyes with high refractive errors.

Body Weights and Measures↗
PubMed2006

Bull's-eye maculopathy in an infant with Leigh disease.

PURPOSE: To report a bull's-eye maculopathy-like fundus abnormality in an infant with Leigh disease. DESIGN: Observational case report. METHODS: We reviewed the medical, ophthalmic, and genetic records of an eight-month-old boy who presented with hypotonia and bilaterally decreased vision. RESULTS: The ophthalmic examination revealed poor fixation, marked hyperopia, attenuated retinal vessels, and bull's-eye maculopathy. A white blood cell mitochondrial DNA analysis demonstrated a T to G mutation at position 8993 in the mitochondrial ATPase 6 gene. A skeletal muscle biopsy was homoplasmic for this mutation, consistent with a severe mitochondrial disorder. CONCLUSION: Leigh disease should be included in the differential diagnosis of patients presenting with neurologic deficits and a bull's-eye maculopathy.

Adenosine Triphosphatases↗
PubMed2005

Retinal serotonin, eye growth and myopia development in chick.

Myopia (short-sightedness) is a visual problem associated with excessive eye growth and vitreous chamber expansion. Within the eye serotonin (5-hydroxytryptamine, 5-HT) appears to have a variety of effects, it alters retinal amacrine cell processing, increases intraocular pressure, constricts ocular blood vessels, and is also mitogenic. This study sought to determine the role of the retinal serotonin system in eye growth regulation. Myopia was produced in 7-day-old chicks using -15 D spectacle lenses (LIM) and form deprivation (FDM). The effect on LIM and FDM of daily intravitreal injections of a combination of 5-HT receptor antagonists (1, 10, 50 microM), 5-HT(2) selective antagonist (Mianserin 0.5, 20 microM) or 5-HT (1, 10, 50 microM) were assessed. Counts were performed of serotonin and tyrosine hydroxylase positive neurons and the relative density used to account for areal changes due to eye growth. The effect of LIM and lens-induced hyperopia (LIH) on the numbers of 5-HT-containing amacrine cells in the retina were then determined. The combination of 5-HT receptor antagonists inhibited LIM by approximately half (1 microM RE: -7.12+/-1.0 D, AL: 0.38+/-0.06 mm vs. saline RE: -13.19+/-0.65 D, AL: 0.64+/-0.03 mm. RE: p<0.01, AL: p<0.01), whereas FDM was not affected (1 microM RE: -8.88+/-1.10 D vs. saline RE: -9.28+/-1.38 D). The selective antagonist was slightly less effective at inhibiting LIM (0.5 microM RE: -9.02+/-1.01 D). These data suggest that serotonin has a stimulatory role in LIM, although high doses of serotonin were inhibitory (1 microM RE: -9.30+/-1.34 D). 5-HT immunoreactivity was localised to a subset of amacrine cell bodies in the inner nuclear layer of the retina, and to two synaptic strata in the inner plexiform layer. LIM eyes had increased numbers of 5-HT-containing amacrine cells in the central retina (12.5%). Collectively, these results suggest that manipulations to the serotonin system can alter the eye growth process but the role of this transmitter system within this process remains unclear.

Amacrine Cells↗
PubMed2006

Acute effects of dietary retinoic acid on ocular components in the growing chick.

When the eyes of chicks are induced to grow toward myopia or hyperopia by having them wear spectacle lenses or diffusers, opposite changes take place in the retina and choroid in the synthesis and levels of all-trans Retinoic Acid (RA). To explore whether RA plays a causal role in the regulation of eye growth, we fed young chicks RA (doses 0.5 to 24 mg/kg) either twice a day or on alternate days or only once. Refractive error was measured with a Hartinger refractometer; ocular length, lens-thickness and choroidal thickness were measured by A-scan ultrasound. The amount of RA present in ocular tissues was determined using HPLC. Oral delivery of RA effectively increased RA in ocular tissues within 8h. During the first day after feeding RA at levels above 8 mg/kg, the rate of ocular elongation tripled, the choroid thickened and lens thickening was inhibited. The day following a dose of RA, the rate of ocular elongation was inhibited and the lens thickened more than normal. Nonetheless, the cumulative effect of repeated doses was that the eye became longer and the lens became thinner than normal, with no net change in refractive error. The rate of elongation was also increased by feeding 13-cis RA, and was reduced by citral, an inhibitor of RA synthesis. Surprisingly, birds fed RA while being kept in darkness also had normal refractive errors despite increased ocular elongation, and birds wearing either +6D or -6D spectacle lenses compensated normally for the lenses despite the enhanced ocular elongation caused by the RA. These results suggest that RA may act at the level of a coordinated non-visual regulatory system which controls the growth of the various ocular components, arguing that emmetropization does not depend entirely on vision.

Animals↗
PubMed2005

Esotropia associated with early presbyopia caused by inappropriate muscle length adaptation.

BACKGROUND: The purpose of this study is to investigate the occurrence of esotropia accompanying early presbyopia. The two primary long-term mechanisms for maintenance of ocular alignment are vergence adaptation (neurologic) and muscle length adaptation (anatomic). Both mechanisms depend upon disparity-driven motor fusion for proper operation. A possible cause for an esotropic shift in early presbyopic adults with insufficient or absent disparity-driven motor fusion is inappropriate muscle length adaptation (medial rectus muscle shortening) occurring in response to increased convergence tonus accompanying increased accommodative effort. METHODS: Of 617 patients, age 10 and older who underwent surgery for esotropia during the period of 1980 to 1996, the age when the deviation occurred or worsened could be determined with confidence in 140. A plot was made of the number of these patients versus the age of onset of the deviation. This was compared with a similar plot of patients operated for exotropia. RESULTS: A statistically significant increase (P = 0.017) in the incidence of an esotropic shift in the age range from 30 to 50 years was found when compared with the incidence of an exotropic shift. CONCLUSION: If the postulated mechanism is correct, full correction of any hyperopia as well as prompt prescription of a reading add (or conversion to monovision correction) may help prevent further progression of small esodeviations accompanying early presbyopia.

Accommodation, Ocular↗
PubMed2004

Autorefraction as an outcome measure of laser in situ keratomileusis.

PURPOSE: To determine the limits of agreement between subjective refraction and autorefraction before and after laser in situ keratomileusis (LASIK) to assess whether autorefraction is a valid refractive outcome measure of refractive surgery. SETTING: Ultralase, Leeds, United Kingdom. METHOD: The prospective study involved consecutive preoperative normal patients and post-LASIK patients who had autorefraction using the Nidek ARK 700A autorefractor and careful subjective refraction (masked to autorefraction). Inclusion criteria were age greater than 18 years and healthy eyes with a visual acuity better than 0.1 logMAR (6/7.5) with or without previous LASIK. Refractions were compared by spherical equivalent (SE) using Bland-Altman limits of agreement and astigmatic vector difference using the median and the 95th percentile. The effect of time after treatment and treatment strength were explored. RESULTS: Data were collected from 208 preoperative patients and 237 post-LASIK patients. Preoperatively, the agreement between subjective refraction and autorefraction for the SE was -0.10 diopter (D) +/- 0.35 (SD) and the median difference for the astigmatic vector was 0.28 D with a 95th percentile of 0.72 D. Post-LASIK, the SE agreement was similar, -0.09 +/- 0.39 D, but the astigmatic vector agreement decreased slightly with a median of 0.31 D and a 95th percentile of 1.02 D. This decrease reflected poorer agreement in patients whose pre-LASIK refractive error was greater than +4.00 D. Removing this group brought the median astigmatic difference post-LASIK to 0.27 D with a 95th percentile of 0.87 D, similar to that in the preoperative normals. The percentage within +/-0.50 D and +/-1.00 D of the attempted correction was 56.1% and 78.5%, respectively, with subjective refraction and 51.2% and 78.1%, respectively, with autorefraction. CONCLUSIONS: Autorefraction showed excellent agreement with subjective refraction and was unaffected by refractive surgery except after LASIK for high hyperopia. Most outcomes were correctly classified in the standard categories (+/-0.50 D, +/-1.00 D), illustrating that autorefraction is a valid outcome measure of refractive surgery.

Adult↗
PubMed2005

Photoablative inlay laser in situ keratomileusis (PAI-LASIK) in the rabbit model.

PURPOSE: To evaluate the suitability, biocompatibility, and efficacy of a proprietary hydrogel photoablative inlay (PAI) for use during laser in situ keratomileusis (LASIK). SETTING: Laboratory study, Tulane University Health Sciences Center, New Orleans, Louisiana, USA. METHODS: Eight rabbits (1 eye each) underwent the PAI-LASIK procedure; 4 eyes had a disk-shaped inlay and 4, a donut-shaped inlay. Preoperatively, the hydrogel material was ablated with a programmed correction of 5.0 diopters of hyperopia or myopia. RESULTS: The eyes were followed for 1 to 16 months. No eye showed signs of rejection or extrusion of the PAI. There was no significant difference in corneal clarity or the healing rate between eyes with donut-shaped PAIs and those with disk-shaped PAIs. One eye with a donut-shaped PAI had minimal corneal haze. The remaining inlays did not opacify or fracture during ablation. CONCLUSION: The hydrogel material can be used for the proposed PAI-LASIK procedure.

Animals↗
PubMed2005

Intraoperative management of iris prolapse using iris hooks.

Iris prolapse has become an unusual and generally benign event in routine cataract surgery using endocapsular phacoemulsification techniques. We operated on the second eye of a patient with hyperopia whose first eye surgery in our care had been uneventful. In the second eye, as soon as the phaco incision was made and hydrodissection begun through the primary incision, the iris repeatedly prolapsed through the incision. This was managed definitively by applying iris hooks, 1 at each side of the primary incision, to the pupillary border so the prolapsing iris was held peripherally in the anterior chamber and under modest tension.

Aged↗
PubMed2005

Two-step procedure to enlarge small optical zones after photorefractive keratectomy for high myopia.

We describe a method for the visual rehabilitation of patients with small optical zones and related complaints after photorefractive keratectomy (PRK) and laser in situ keratomileusis for high myopia. In many of these cases from the early 1990s, low central corneal thickness in combination with residual myopia did not allow for enlargement of the small optical zone by a topography-guided treatment in the first instance. We therefore perform, as a first step, a clear lens exchange aiming at hyperopia. This enables us to perform, as a second step, a topography-guided customized PRK with marked enlargement of the optical zone. Such 2-step procedures may be of great benefit to patients with small optical zones and low central corneal thickness.

Adult↗
PubMed2006

Iris-fixated toric phakic intraocular lens: Three-year follow-up.

PURPOSE: To evaluate the 3-year safety, efficacy, predictability, and stability of iris-fixated toric phakic intraocular lens (pIOL) implantation for the correction of myopia or hyperopia with astigmatism. SETTING: Department of Ophthalmology, Johannes Gutenberg University, Mainz, and Department of Ophthalmology, University Clinic, Bochum, Germany. METHODS: A prospective clinical trial of 40 eyes of 23 patients with high ametropia and astigmatism was conducted. Best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity, refraction, astigmatism, intraocular pressure, slitlamp biomicroscopy, and indirect ophthalmoscopy were measured preoperatively and postoperatively. RESULTS: Of the 40 eyes, 28 were myopic and 12 were hyperopic. Three years postoperatively, 70% of eyes were within +/-1.00 diopter (D) of the targeted refraction. In the myopic group, mean preoperative BSCVA was 20/40 and improved postoperatively to 20/25. Sixty-six percent of eyes gained 1 or more lines from the preoperative BSCVA. The mean cylinder decreased from -3.58 D +/- 1.26 (SD) preoperatively to -1.15 +/- 1.01 D postoperatively. In the hyperopic group, preoperative BSCVA was 20/25 and improved to 20/20 postoperatively. Thirty-six percent of eyes gained 1 or more lines from the preoperative BSCVA. The mean cylinder decreased from -3.37 +/- 0.88 D to -1.53 +/- 0.69 D postoperatively. The correction was stable in all eyes 3 years after surgery. No potentially sight-threatening complications occurred. CONCLUSION: The 3-year follow-up showed the iris-fixated toric pIOL was effective in correcting high ametropia and astigmatism.

Adult↗
PubMed2006

Visual and refractive status at different focal distances after implantation of the ReSTOR multifocal intraocular lens.

PURPOSE: To evaluate the visual acuity and determine the refraction in emmetropic pseudophakic eyes at different focal distances after implantation of the AcrySof SA 60D3 ReSTOR multifocal intraocular lens (IOL) (Alcon Laboratories). SETTING: Private clinical practice. METHODS: Thirty-seven eyes of 20 patients received the ReSTOR IOL. Visual acuity was measured at several distances, and best distance corrected, best intermediate corrected (60 cm), and best near corrected (33 cm) visual acuities were determined 3 months after surgery. Subjective outcomes were assessed by a questionnaire. RESULTS: Postoperatively, 36 of 37 eyes (97.3%) were within +/-1.00 diopter (D) of the manifest refraction spherical equivalent and cylinder. Monocularly, the mean best distance corrected, best distance corrected intermediate, and best distance corrected near visual acuities were 20/20, 20/46, and 20/23, respectively. The best distance corrected acuities at 40, 50, 60, and 70 cm were significantly worse than the best distance corrected and best distance corrected near acuities (P<.05). On the questionnaire, all patients noted intermediate blur, but 75% had little or no difficulty seeing and were bothered by the blur occasionally or never. The mean additional add to best distance correction for best intermediate corrected visual acuity was +1.20 diopters (D) +/- 0.27 D or -1.68 +/- 0.24 D and for best near corrected visual acuity, -0.26 +/- 0.24 D. CONCLUSIONS: Implantation of the ReSTOR IOL offered excellent visual acuity at distance and near distance and functional visual acuity in the intermediate range. For patients who need excellent vision at intermediate range, leaving 1 eye with distance myopia or hyperopia to compensate for intermediate vision may provide consistent good binocular vision over the full range in cases of bilateral implantation.

Acrylic Resins↗
PubMed2004

Using InterWave aberrometry to measure and improve the quality of vision in LASIK surgery.

OBJECTIVE: To compare visual outcomes in eyes undergoing aberrometry-guided (InterWave) LASIK with those in eyes undergoing standard LASIK treatment based upon refractive measures. DESIGN: Single-center, comparative, interventional, consecutive case series. PARTICIPANTS: Four hundred two consecutive eyes undergoing LASIK were analyzed retrospectively. One group, 106 eyes undergoing primary LASIK and 224 eyes undergoing LASIK enhancement, was treated with standard LASIK treatment using a 5.5-mm optical zone, 1.5-mm transition zone laser with the settings determined by manifest refraction. The second group, 44 untreated (primary) eyes and 28 previously treated (enhancement) eyes, received a multipass, multistage treatment in which the laser settings for each stage were determined by aberrometry measurements. Eyes with desired monovision (undercorrected) outcome and preoperative hyperopia were excluded from the study. INTERVENTION: An aberrometry-guided laser treatment (InterWave LASIK) was compared with the standard LASIK treatment based upon the manifest refraction. MAIN OUTCOME MEASURES: Uncorrected visual acuity (VA), manifest refraction, best spectacle-corrected VA (BSCVA), severity of halos, and root mean square (RMS) retinal blur area measured at 3 months postoperatively. RESULTS: Three months postoperatively there was no difference in uncorrected VA, BSCVA, refraction, or RMS retinal blur areas for pupil sizes of 3.5 mm between eyes treated by InterWave and those treated by standard LASIK. However, InterWave LASIK reduced the retinal blur area by 48% (P<0.0103) and 58% (P<0.0004) in primary cases and 43% (P<0.0430) and 74% (P<0.0271) in enhancement cases, respectively, for pupil sizes of 4.5 and 6.5 mm relative to standard LASIK treatments. Patients undergoing InterWave-guided treatment reported less severity of halo (0.37 vs. 0.98 [P<0.016] for primary cases and 0.35 vs. 0.73 [P<0.04] for enhancement cases). CONCLUSION: InterWave LASIK achieved acuity and refractive results equivalent to those of standard LASIK treatment based upon refraction, but resulted in superior quality mesopic vision.

Adult↗
PubMed2005

Visual acuity and the causes of visual loss in a population-based sample of 6-year-old Australian children.

PURPOSE: To describe the distribution of visual acuity and causes of visual loss in a representative sample of Australian schoolchildren. DESIGN: Population-based cross-sectional study. PARTICIPANTS: One thousand seven hundred thirty-eight predominantly 6-year old children examined during 2003 to 2004. METHODS: Logarithm of the minimum angle of resolution (logMAR) visual acuity was measured in both eyes before and after pinhole correction and with spectacles if worn. Cycloplegic autorefraction (cyclopentolate) and detailed dilated fundus examination were performed. MAIN OUTCOME MEASURES: Visual impairment was defined as any (visual acuity <20/40; <40 letters) or severe (visual acuity < or =20/200; 0-5 letters) for both better and worse eyes. Myopia was defined as spherical equivalent (SE) refraction < or =-0.50 diopters (D), and hyperopia as SE refraction > or =+2.0 D, deemed significant when > or =+3.0 D. Astigmatism was defined as cylinder > or =1.0 D and anisometropia as SE refraction difference between eyes at least 1.0 D. Amblyopia was defined as corrected visual acuity <0.3 logMAR units (<20/40; <40 letters) in the affected eye not attributable to any underlying structural abnormality of the eye or visual pathway, together with a 2-logMAR line difference between the eyes and presence of an amblyogenic risk factor. RESULTS: The mean visual acuity of this sample was 20/25 (49.3 letters). Uncorrected visual impairment was found in the better eye of 23 children (1.3%) and in the worse eye of 71 children (4.1%). The prevalence was higher in girls than boys and among children of lower socioeconomic status. Refractive error was the most frequent cause, accounting for 69.0%, followed by amblyopia (22.5%). Astigmatism was the principle refractive error causing visual impairment and was frequently uncorrected. Presenting visual impairment (using current glasses if worn) was found in the better and worse eyes of 15 children (0.9%) and 54 children (2.8%), respectively. This was mainly due to under corrected or uncorrected refractive error. CONCLUSIONS: This study has documented a relatively low prevalence of visual impairment in a population of Australian children. Uncorrected astigmatism and amblyopia were the most frequent causes.

Child↗
PubMed2006

Factors associated with childhood strabismus: findings from a population-based study.

PURPOSE: To describe strabismus prevalence and associated factors in a representative sample of 6-year-old Australian children. DESIGN: Population-based cross-sectional study. PARTICIPANTS: One thousand seven hundred thirty-nine predominantly 6-year-old children resident in Sydney examined in 2003 and 2004. METHODS: Cover testing was performed at near and distance fixation, and with spectacles if worn. Logarithm of the minimum angle of resolution visual acuity was measured in both eyes before and after pinhole correction, after correcting any cylindrical refraction >0.50 diopters and with spectacles, if worn. Cycloplegic autorefraction (cyclopentolate) and detailed dilated fundus examination were performed. Each child's medical and perinatal histories were sought in a detailed parental questionnaire. MAIN OUTCOME MEASURES: Strabismus was defined as any heterotropia at near or distance fixation, or both, on cover testing. Microstrabismus was defined as a deviation of fewer than 10 prism diopters. RESULTS: Strabismus was diagnosed in 48 children (2.8% of the population), 5 of whom had previously undergone surgical correction; 26 children (54%) had esotropia, 14 (29%) had exotropia, 7 (15%) had microstrabismus, and 1 child had VIth cranial nerve palsy. Prematurity was associated with a 5-fold increase in the risk of esotropia (odds ratio, 5.0; 95% confidence interval, 1.8-14.1). Visual impairment (with presenting correction) was significantly more common in children with (22.9%) than without (1.3%) strabismus (P<0.0001). The presence of strabismus was significantly associated with hyperopia, astigmatism, anisometropia, and amblyopia (P<0.0001). CONCLUSIONS: This report documents the prevalence of strabismus and its relation to other ocular signs and visual impairment in a representative sample of Australian school children. Presence of strabismus was significantly associated with prematurity.

Child↗
PubMed2006

Refractive error and visual impairment in school children in rural southern China.

PURPOSE: To assess the prevalence of refractive error and visual impairment in school children in a rural area of southern China. DESIGN: Prospective cross-sectional survey. PARTICIPANTS: Two thousand four hundred children from junior high schools in Yangxi County. METHODS: Random selection of classes from the 3 junior high school grade levels was used to identify the study sample. Children from 36 classes in 13 schools were examined in April 2005. The examination included visual acuity (VA) testing; ocular motility evaluation; cycloplegic autorefraction; and examination of the external eye, anterior segment, media, and fundus. MAIN OUTCOME MEASURES: Distance VA and cycloplegic refraction. RESULTS: Among 2515 enumerated children, 2454 (97.6%) were examined. The study population consisted of the 2400 children between 13 and 17 years old. Prevalences of uncorrected, presenting, and best-corrected VA < or = 20/40 in the better eye were 27.0%, 16.6%, and 0.46%, respectively. Sixty percent of those who could achieve acuity > or =20/32 in at least one eye with best correction were without the necessary spectacles. Refractive error was the cause in 97.1% of eyes with reduced vision; amblyopia, 0.81%; other causes, 0.67%; and unexplained causes, 1.4%. Myopia (spherical equivalent, -0.50 diopters [D] or more in either eye) affected 36.8% of 13-year-olds, increasing to 53.9% of 17-year-olds. Myopia was associated with higher grade level, female gender, schooling in the county urban center, and higher parental education. Hyperopia (+2.00 D or more) affected approximately 1.0% in all age groups. Astigmatism (> or =0.75 D) was present in 25.3% of all children. CONCLUSIONS: Reduced vision because of uncorrected myopia is a public health problem among school-age children in rural China. Effective VA screening strategies are needed to eliminate this easily treated cause of visual impairment.

Adolescent↗