Significant Refractive Error Research Articles

Prevalence of Visual Disorders among Urban Palestinian Preschool Children

Background: Childhood blindness is a major public health concern since 40% of visual disorders that can cause blindness among children are preventable. Vision screening programs among preschool children have been implemented in several countries as a tool for early detection and intervention of visual disorders. In Palestine, there is a lack of scientific data on the prevalence of visual disorders among children. In addition, vision-screening programs that are currently implemented are neither validated nor effective. Objective: Using validated vision screening protocols, a cross-sectional study is conducted to determine the prevalence of visual disorders among urban Palestinian preschool children between the ages of 3 to 5 years in Nablus city. Methods: All children attending eight preschools selected using single-stage cluster sampling technique, underwent a validated vision screening administered by trained eye care professionals. The screening protocol was based on a combination of clinical assessment adopted from the Modified Clinical Technique and the Vision in Preschoolers studies, including assessment of visual acuity, ocular alignment, depth perception, color vision, non-cycloplegic retinoscopy, and ocular health. A pass-fail criterion was used to refer all children who did not attend the vision screening for comprehensive eye examination, including cycloplegic retinoscopy and a dilated fundus exam. A chi-squared test was used to determine any association between visual disorders and their independent risk factors. Results: A total number of 764 children underwent vision screening. Out of the 290 children who did not attend the vision screening, 127 children responded to the referral call for comprehensive eye examinations. Refractive error was the most prevalent visual disorder with a prevalence of (29.37%), followed by amblyopia (4.10%), color vision deficiency (1.24%), strabismus (1.24%), and ocular health abnormalities (0.70%). There was no age (p=0.35) and gender (p=0.32) variation in children having refractive errors. Anisometropia was the leading cause for amblyopia (1.32%, n=7), followed by significant refractive error (1.13%, n=6) and strabismus (0.37%, n=2). Conclusion: Refractive error was the most prevalent visual disorder affecting Palestinian preschoolers in Nablus. Anisometropia and significant refractive errors were found to be the major causes of amblyopia. Effective nationwide preschool vision screening programs should be implemented in Palestine to screen amblyogenic risk factors.

Long-term Outcomes of Bowman's Membrane Relaxation for Enhancement of Femtosecond Intrastromal Lenticule Implantation Performed for the Management of High Hyperopia.

To evaluate the feasibility and report long-term outcomes with Bowman's membrane relaxation (BMR) for enhancing the residual refractive error following femtosecond intrastromal lenticule implantation (FILI). BMR was performed using a Hessburg-Barron trephine to create a circular incision into the Bowman's membrane and anterior corneal fibers up to the depth of approximately 120 to 130 µm. After enhancement, clinical outcomes were analyzed for a mean period of 36 months (range: 14 to 57 months). Four eyes of 3 patients (mean age: 29 years) underwent enhancement with BMR for a significant residual refractive error of +2.25 diopters (D) spherical equivalent following FILI for high hyperopia (mean spherical equivalent: +7.00 D). After BMR, the residual refraction reduced to +0.31 D, resulting in improvement in uncorrected distance visual acuity from 0.55 to 0.33 logMAR. The mean front keratometry values increased from 46.20 to 49.30 D, and the mean back keratometry values increased from -5.90 to -6.30 D following BMR, the latter returning to the baseline (pre-FILI) value of -6.30 D. An increase in Q-value with a corresponding increase in higher order aberrations was observed. Corneal biomechanics indicated reduction of stiffness and other parameters after enhancement. No intraoperative or postoperative complications were noted. BMR may be an effective technique for enhancement of residual hyperopia following tissue addition techniques such as FILI. BMR may reverse the posterior curvature changes, negating the steepening effect of the anterior cornea following tissue addition, potentially aiding in the enhancement. [J Refract Surg. 2022;38(2):134-141.].

AAPOS uniform guidelines for instrument-based pediatric vision screen validation 2021

As instrument-based pediatric vision screening technology has evolved, the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) has developed uniform guidelines (2003, updated 2013) to inform the development of devices that can detect specified target levels of amblyopia risk factors (ARFs) and visually significant refractive error. Clinical experience with the established guidelines has revealed an apparent high level of over-referral for non-amblyopic, symmetric astigmatism, prompting the current revision. The revised guidelines reflect the expert consensus of the AAPOS Vision Screening and Research Committees. For studies of automated screening devices, AAPOS in 2021 recommends that the gold-standard confirmatory comprehensive examination failure levels include anisometropia >1.25 D and hyperopia >4.0 D. Astigmatism >3.0 D in any meridian and myopia <-3 D should be detected in children <48 months, whereas astigmatism >1.75 D and myopia < -2 D should be detected after 48 months. Any media opacity >1 mm and manifest strabismus of >8Δ should also be identified. Along with performance in detecting ARFs and refractive error, validation studies should also report screening instrument performance with regard to presence or absence of amblyopia. Instrument receiver operating characteristic curves and Bland-Altman analysis are suggested to improve comparability of validation studies. Examination failure criteria have been simplified and the threshold for symmetric astigmatism raised compared to the 2013 guidelines, whereas the threshold for amblyogenic anisometropia has been decreased. After age 4 years, lower magnitudes of symmetric astigmatism and myopia are also targeted despite a low risk of amblyopia, because they can influence school performance and may warrant consideration of myopia prevention therapy.

Moebius Syndrome

We report a case of a 13-year-old female who presented in the medical emergency with seizures and was referred to the ophthalmology department for fundus examination. On examination, she was found to have bilateral asymmetric VIth and VIIth nerve palsy, bilateral horizontal gaze paresis (right &gt; left), tongue atrophy, mask-like face, normal intelligence, prominent lower lip, and history of treated club foot. She was diagnosed to have Moebius syndrome based on the above findings. She also had some atypical features such as head tilt, significant refractive error, anisometric amblyopia, and horizontal nystagmus. Her computed tomography scan of the head revealed neurocysticercosis.

Vision Screening, Vision Disorders, and Impacts of Hyperopia in Young Children: Outcomes of the Vision in Preschoolers (VIP) and Vision in Preschoolers - Hyperopia in Preschoolers (VIP-HIP) Studies.

This review summarizes clinically relevant outcomes from the Vision in Preschoolers (VIP) and VIP-Hyperopia in Preschoolers (VIP-HIP) studies. In VIP, refraction tests (retinoscopy, Retinomax, SureSight) and Lea Symbols Visual Acuity performed best in identifying children with vision disorders. For lay screeners, Lea Symbols single, crowded visual acuity (VA) testing (VIP, 5-foot) was significantly better than linear, crowded testing (10-foot). Children unable to perform the tests (<2%) were more likely to have vision disorders than children who passed and should be referred for vision evaluation. Among racial/ethnic groups, the prevalence of amblyopia and strabismus was similar while that of hyperopia, astigmatism, and anisometropia varied. The presence of strabismus and significant refractive errors were risk factors for unilateral amblyopia, while bilateral astigmatism and bilateral hyperopia were risk factors for bilateral amblyopia. A greater risk of astigmatism was associated with Hispanic, African American, and Asian race, and myopic and hyperopic refractive error. The presence and severity of hyperopia were associated with higher rates of amblyopia, strabismus, and other associated refractive error. In the VIP-HIP study, compared to emmetropes, meaningful deficits in early literacy were observed in uncorrected hyperopic 4- and 5-year-olds [≥+4.0 diopter (D) or ≥+3.0 D to ≤+6.0 D associated with reduced near visual function (near VA 20/40 or worse; stereoacuity worse than 240")]. Hyperopia with reduced near visual function also was associated with attention deficits. Compared to emmetropic children, VA (distance, near), accommodative accuracy, and stereoacuity were significantly reduced in moderate hyperopes, with the greatest risk in those with higher hyperopia. Increasing hyperopia was associated with decreasing visual function.

Using electronic medical record data to establish and monitor the distribution of refractive errors,

ObjectiveTo establish the baseline distribution of refractive errors and associated factors amongst a population that attended primary care optometry clinics. DesignRetrospective cross sectional cohort study of electronic medical records (EMR). MethodsElectronic medical record data was extracted from forty optometry clinics, representing a mix of urban and rural areas in Ireland. The analysis was confined to demographic and clinical data gathered over a sixty-month period between 2015 and 2019. Distribution rates were calculated using the absolute and relative frequencies of refractive error in the dataset, stratified for age and gender using the following definitions: high myopia ≤ -6.00 D, myopia ≤ -0.50 D, hyperopia ≥ +0.50 D, astigmatism ≤ -0.75 DC and anisometropia ≥ 1.00 D. Visual acuity data was used to explore vision impairment rates in the population. Further analysis was carried out on a gender and age-adjusted subset of the EMR data, to match the proportion of patients in each age grouping to the population distribution in the most recent (2016) Irish census. Results153,598 clinic records were eligible for analysis. Refractive errors ranged from -26.00 to +18.50 D. Myopia was present in 32.7%, of which high myopia represented 2.4%, hyperopia in 40.1%, astigmatism in 38.3% and anisometropia in 13.4% of participants. The clinic distribution of hyperopia, astigmatism and anisometropia peaked in older age groups, whilst the myopia burden was highest amongst people in their twenties. A higher proportion of females were myopic, whilst a higher proportion of males were hyperopic and astigmatic. Vision impairment (LogMAR > 0.3) was present in 2.4% of participants. In the gender and age- adjusted distribution model, myopia was the most common refractive state, affecting 38.8% of patients. ConclusionAlthough EMR data is not representative of the population as a whole, it is likely to provide a reasonable representation of the distribution of clinically significant (symptomatic) refractive errors. In the absence of any ongoing traditional epidemiological studies of refractive error in Ireland, this study establishes, for the first time, the distribution of refractive errors observed in clinical practice settings. This will serve as a baseline for future temporal trend analysis of the changing pattern of the distribution of refractive error in EMR data. This methodology could be deployed as a useful epidemiological resource in similar settings where primary eyecare coverage for the management of refractive error is well established.

Detection of Significant Hyperopia in Preschool Children Using Two Automated Vision Screeners.

Moderate to high uncorrected hyperopia in preschool children is associated with amblyopia, strabismus, reduced visual function, and reduced literacy. Detecting significant hyperopia during screening is important to allow children to be followed for development of amblyopia or strabismus and implementation of any needed ophthalmic or educational interventions. This study aimed to compare the sensitivity and specificity of two automated screening devices to identify preschool children with moderate to high hyperopia. Children in the Vision in Preschoolers (VIP) study were screened with the Retinomax Autorefractor (Nikon, Inc., Melville, NY) and Plusoptix Power Refractor II (Plusoptix, Nuremberg, Germany) and examined by masked eye care professionals to detect the targeted conditions of amblyopia, strabismus, or significant refractive error, and reduced visual acuity. Significant hyperopia (American Association for Pediatric Ophthalmology and Strabismus definition of hyperopia as an amblyopia risk factor), based on cycloplegic retinoscopy, was >4.00 D for age 36 to 48 months and >3.50 D for age older than 48 months. Referral criteria from VIP for each device and from a distributor (PediaVision) for the Power Refractor II were applied to screening results. Among 1430 children, 132 children had significant hyperopia in at least one eye. Using the VIP referral criteria, sensitivities for significant hyperopia were 80.3% for the Retinomax and 69.7% for the Power Refractor II (difference, 10.6%; 95% confidence interval, 7.0 to 20.5%; P = .04); specificities relative to any targeted condition were 89.9 and 89.1%, respectively. Using the PediaVision referral criteria for the Power Refractor, sensitivity for significant hyperopia was 84.9%; however, specificity relative to any targeted condition was 78.3%, 11.6% lower than the specificity for the Retinomax. Analyses using the VIP definition of significant hyperopia yielded results similar to when the American Association for Pediatric Ophthalmology and Strabismus definition was used. When implementing vision screening programs for preschool children, the potential for automated devices that use eccentric photorefraction to either miss detecting significant hyperopia or increase false-positive referrals must be taken into consideration.

Visual acuity and refractive findings in children prescribed glasses from a school-based vision program

We report visual acuity improvement and refractive profiles in children prescribed glasses by a school-based vision program (SBVP) in Baltimore, Maryland. In this cross-sectional analysis, pre-kindergarten through 8th grade students who failed vision screening underwent an eye examination. Students prescribed glasses are included. Visual acuity improvement was the difference between presenting and best-corrected visual acuity based on noncycloplegic manifest refraction. Clinically significant refractive error (CSRE) was defined as ≥0.75 D myopia, ≥2.00 D hyperopia without strabismus, ≥1.00 D hyperopia with esodeviation, or ≥1.50 D astigmatism AND presenting visual acuity ≤20/40 or ≥2-line interocular difference with the better-seeing eye ≤20/30. Characteristics associated with greater visual acuity improvement were explored. Of the 4,972 students, mean age was 9.4 ± 2.7 years; 77% were black, and 18% were Hispanic. Myopia, hyperopia, astigmatism, and CSRE were found in 65%, 24%, 60%, and 46% students, respectively. In the better-seeing eyes, 70% gained ≥2 lines. Of students with CSRE, improvement of at least 5 lines in the worse-seeing eye increased from 30.9% in pre-kindergarten and kindergarten to 77.3% in 7th and 8th grade (Ptrend < 0.001). Students with CSRE had a higher rate of gaining at least 2 lines' improvement in their worse-seeing eyes compared with those without (98.7% vs 80.6%). Older students as well as black and Hispanic students were more likely to have improvement of at least 2 lines. Most students prescribed glasses from our SBVP had clinically significant visual deficits corrected.

Pattern of oculomotor and visual function in children with hydrocephalus

To investigate the ocular motility disturbances, optic nerve changes, and refractive errors in children with or without surgically treated hydrocephalus. This retrospective study included 63 subjects diagnosed with hydrocephalus between 2007 and 2019 at the Baskent University Hospital. Full orthoptic and ophthalmic examination and brain magnetic resonance imaging were performed in all subjects. The mean age of patients was 68.4±27.6 months, and the mean follow-up time was 21.3±5.2 months. Twenty-one (51.2%) patients had esotropia (ET), and 14 (34.1%) had exotropia (XT). Of the patients with ET, 9 (14.2%) had a sixth nerve palsy. Four patients (6.3%) had a fourth nerve palsy, and 1 had a superior rectus palsy. Eleven patients had manifest, and 2 latent, nystagmus. Thirteen (20.6%) patients had optic disc abnormalities. The mean BCVA was 0.4±0.2 (0.05-1.0) in the right eye and 0.5±0.2 (0.1-1.0) in the left eye. Of the 19 (30.1%) patients who had a significant refractive error, 9 (47.3%) had hyperopia. Thirty-six (57.1%) patients had ventriculoperitoneal shunt surgery, and 11 (30.5%) of them had shunt revision due to occlusion. Ocular motility disorders were found to be significantly more common in patients who underwent single shunt surgery and shunt revision than those who had no surgical procedure (P=0.041and P=0.032, respectively). The evaluation of ocular motility disorders and visual dysfunction in hydrocephalic children can be a source of valuable information when diagnosing and following the disease.

Physician Prescribing and Referral Patterns in Children with Cerebral Visual Impairment.

Cerebral visual impairment (CVI) is the leading cause of visual impairment in the developed world. Providing children with CVI with the appropriate treatment ensures the best possible visual outcome and potentially improves quality of life. The purpose of this study was to determine physician prescribing and visual rehabilitation referral patterns in children with CVI. A retrospective chart review was completed on children with CVI examined at Cincinnati Children's Hospital Medical Center from January 1, 2008, to March 1, 2018. Significant refractive error warranting correction was determined using the American Academy of Ophthalmology Preferred Guidelines and the American Association for Pediatric Ophthalmology and Strabismus Vision Screening Committee Guidelines. The CVI Range was used as a surrogate to categorize CVI severity. A total of 194 children were included. Sixty-eight (35%) had refractive error warranting correction and were prescribed glasses (group RC), 99 (51%) did not have refractive error warranting correction and were not prescribed glasses (group NRNC), 20 (10%) had refractive error warranting correction but were not prescribed glasses (group RNC), and 7 (4%) did not have refractive error warranting correction but were prescribed glasses (group NRC). There was greater than one-line Snellen equivalent difference between group RC (20/156) and group RNC (20/221). There was greater than six-line Snellen equivalent difference between group NRNC (20/149) and group NRC (20/35). Mean CVI Range score 2 values for each group were 5.9, 4.6, 4.8, and 7.1. Children with less severe CVI were less likely to have significant refractive error but given glasses. Despite significant refractive error, children with more severe CVI were not prescribed glasses. Children with very low visual function were not prescribed glasses as frequently, possibly limiting their visual rehabilitation. Providers should ensure that all children with CVI are correctly prescribed glasses to provide the best possible visual outcome.

Comparison of refractive outcomes after combined cataract and glaucoma surgery: trabeculectomy and glaucoma drainage device implantation.

To investigate the refractive outcome of combined cataract surgery and glaucoma drainage device (GDD) implantation compared with trabeculectomy and cataract surgery. Department of Ophthalmology, National University Health System, Singapore. Retrospective cohort study. 206 eyes were enrolled for analysis: 50 had combined cataract surgery and trabeculectomy (trabeculectomy group), 50 had combined cataract surgery and GDD implantation (GDD group), and 106 had cataract surgery alone (control group). Refractive prediction error and absolute prediction error of each glaucoma surgery group were compared with the control group. Subgroup analysis was performed in the following axial length (AL) subgroups: short (<22.5 mm), medium (≥22.5 to <25.5 mm), and long (≥25.5 mm). In total, 206 eyes were examined. There was no statistically significant difference in the overall refractive prediction error between the GDD (0.00 ± 0.54 diopters [D]) and the control group (0.10 ± 0.53 D, P = .58). There was significant myopic refractive prediction error in the trabeculectomy group (-0.18 ± 0.88 D, P = .020). In eyes with short AL, a greater absolute prediction error was observed in the GDD group (-0.75 ± 0.43 D, P = .039). Apart from a significant deviation in short AL eyes, combined cataract surgery and GDD implantation demonstrated no significant postoperative refractive prediction error.

Refractive Error Findings in Students Who Failed School-based Vision Screening

ABSTRACT Purpose To report refractive error findings in Baltimore City schoolchildren who failed school-based vision screenings. Methods In this cross-sectional analysis, students pre-kindergarten through 8th grade who failed screenings during school years 2016–2019 received an eye examination, including non-cycloplegic autorefraction and visual acuity (VA) measurements. Refractive error was identified when there was at least: −0.50 diopter (D) spherical equivalent (SE) myopia, +0.50D SE hyperopia, 1.00D astigmatism, or 1.00D anisometropia in either eye. Generalized estimating equation models were used to identify factors associated with clinically significant refractive error, defined as decreased VA and more severe refractive error. Results Of 7520 students who failed screening, 6627 (88%) were analyzed. Clinically significant refractive error and any refractive error were found in 2352 (35.5%) and 5952 (89.8%) students, respectively. Mild myopia (45%, −0.50 D to <-3.00 D SE) and low astigmatism (47%, 1.00 D to <3.00 D cylinder) were the most prevalent types of refractive error. Proportions of students with myopia increased with higher grade levels (Ptrend<0.001). Myopia and astigmatism were more common in black and Latinx. Risk factors for clinically significant refractive error included higher grades (odds ratios [OR] ranged from 1.30 to 2.19 compared with 1st grade, P < .05) and Latinx ethnicity (OR = 1.31, 95%CI: 1.08–1.59). Conclusion A Baltimore school-based vision program identified a substantial number of students with refractive error in a high-poverty urban community. Over 1/3 students who failed vision screening had clinically significant refractive error, with black and Latinx students at higher risk of having myopia and astigmatism.

Ophthalmologic characteristics and outcomes of children with cortical visual impairment and cerebral palsy

Cortical visual impairment (CVI) is the most common cause of pediatric visual impairment in developed countries, and cerebral palsy (CP) is diagnosed in approximately half of children with CVI. It is unknown whether children with CVI who also have CP (CVI+CP) have different characteristics and outcomes (with regard to visual acuity, strabismus, and response to strabismus surgery) than children with CVI without CP (CVI-CP). The medical records of all children with CVI, with and without CP, evaluated at our institution between 2013 and 2019 were retrospectively reviewed. Presentation and outcomes of children with CVI+CP were compared to those with CVI-CP. A total of 151 children with CVI+CP and 153 children with CVI-CP were included. Children with CVI+CP were more likely to be diagnosed with significant refractive error (53.6% vs 41.2%; P=0.03), optic atrophy (46.4% vs 32.7%; P=0.01), and strabismus (82.8% vs 72.5%; P=0.03) at presentation. Good ocular alignment after strabismus surgery was achieved in 30% of children with CVI+CP and 63.6% of children with CVI-CP (P=0.48). Of 9 children with long-term (≥8years) postoperative follow-up, 100% of CVI-CP patients achieved good outcomes compared with 0% of CVI+CP patients (P=0.0079). Visual acuity at presentation and the percentage of patients who experienced improvement in visual acuity did not differ between groups. In our study cohort, children with CVI+CP had a higher likelihood of ophthalmic comorbidities and may have worse long-term strabismus surgery outcomes than children with CVI-CP.

Factors affecting guardians' decision making on clinic-based purchase of children's spectacles in Nigeria.

This study aims to understand the key factors influencing guardians' decisions when purchasing spectacles for their children in semi-urban and urban areas of Cross River State, Nigeria, where a spectacle cross-subsidisation scheme will be implemented. This cross-sectional study was conducted among all consecutive guardians visiting the Calabar (urban), Ugep, Ikom and Ogoja (semi-urban) public eye clinics in Cross River State, southern Nigeria, from August 1 to October 31 2019, and whose children had significant refractive errors (myopia ≤-0.50D, hyperopia ≥1.50D, astigmatism >0.75D) and received spectacles. Guardians were interviewed using a questionnaire which included i) close-ended questions on reasons guardians choose to purchase spectacles for their children in eye clinics, ii) guardians' perceptions of the quality and design of children's current spectacle, iii) factors most heavily influencing their choice of spectacles for children, and iv) open-ended questions to seek guardians' suggestions on how to improve the current spectacle range. All 137 eligible guardians (67.2% women [n = 92]) who visited the selected eye clinics participated in the study (response rate = 100%), with 109 (79.6%) from semi-urban and 28 (20.4%) attending urban clinics. Guardians from both urban and semi-urban clinics prioritised frame design, quality, and material as the main factors affecting their decision when purchasing spectacles for their children. Female guardians and those with higher incomes were both 1.5 times more likely to emphasise frame quality when describing selection criteria for purchasing spectacles for their children than male guardians (p = 0.01) or guardians earning less (p = 0.03). Design, material, and frame quality are key factors influencing guardians when purchasing spectacles for their children in these setting and female guardians or those with higher income prioritise frame quality. This study could guide the planning and implementation of a novel cross-subsidisation scheme in Cross River State.

Accuracy of autorefraction in an adult Indian population.

PurposeAutorefractors allow non-specialists to quickly assess refractive error, and thus could be a useful component of large-scale vision screening programs. In order to better characterize the role of autorefraction for public health outreach programs in resource-limited settings, the diagnostic accuracy of two autorefractors was assessed relative to subjective refraction in an adult Indian population.MethodsAn optometrist refracted a series of patients aged ≥50 years at an eye clinic in Bangalore, India using the Nidek ARK-900 autorefractor first, followed by the 3nethra Royal autorefractor, and then subjective refraction. The diagnostic accuracy of each autorefractor for myopia, hyperopia, and astigmatism was assessed using subjective refraction as the reference standard, and measures of agreement between refractions were calculated.ResultsA total of 197 eyes in 104 individuals (mean age 63 ± 8 years, 52% female) were evaluated. Both autorefractors produced spherical equivalent estimates that were on average more hyperopic than subjective refraction, with a measurement bias of +0.16 D (95%CI +0.09 to +0.23D) for Nidek and +0.42 D (95%CI +0.28 to +0.54D) for 3nethra. When comparing pairs of measurements from autorefraction and subjective refraction, the limits of agreement were approximately ±1D for the Nidek autorefractor and ±1.75D for the 3Nethra autorefractor. The sensitivity and specificity of detecting ≥1 diopter of myopia were 94.6% (95%CI 86.8–100%) and 92.5% (95%CI 88.9–97.5%) for the Nidek, and 89.2% (95%CI 66.7–97.4) and 77.5% (95%CI 71.2–99.4%) for the 3Nethra. The accuracy of each autorefractor increased at greater levels of refractive error.ConclusionsThe sensitivity and specificity of the Nidek autorefractor for diagnosing refractive error among adults ≥50 years in an urban Indian clinic was sufficient for screening for visually significant refractive errors, although the relatively wide limits of agreement suggest that subjective refinement of the eyeglasses prescription would still be necessary.

Diagnostic accuracy of the Parr vision test, single crowded Lea symbols and Spot vision screener for vision screening of preschool children aged 4-5years in Aotearoa/New Zealand.

Preschool children in New Zealand undergo vision screening to detect amblyopia at 4-5years of age. The current test, the Parr vision test, does not meet international visual acuity chart guidelines and has not been validated against other commonly used paediatric vision tests. New Zealand vision screening protocols are also not targeted for detecting other eye conditions such as uncorrected refractive error, which may affect school performance. We compared the Parr vision test with the single crowded Lea symbols and the Spot vision screener for detecting ocular pathology, refractive error and amblyopic risk factors in preschool children. A cross-sectional diagnostic accuracy study recruited children aged 4-5years via convenience sampling from the University of Auckland Optometry Clinic and through primary schools in Auckland, New Zealand. Participants received vision screening with the three different instruments administered by a lay screener. Comprehensive eye examinations were completed by a paediatric optometrist to determine the presence of vision disorders. Of 197 children who received a comprehensive eye examination, 14 (7.1%) had amblyopic risk factors and 43 (21.8%) had significant refractive error (15.7% with astigmatism, 9.1% with hyperopia). The sensitivity for detecting any ocular condition did not differ significantly between the tests (50.0% for Parr, 43.5% for Lea, 42.5% for Spot). Specificity was significantly lower for the Parr vision test (80.8%) than for the Lea symbols (93.4%) and Spot vision screener (98.0%). Adding the Spot vision screener to measurements of visual acuity significantly improved sensitivity in detecting any ocular condition with the Parr vision test (67.5% for Parr/Spot vs 50% for Parr alone), but not with the Lea symbols (52.5% for Lea/Spot vs 43.5% for Lea alone). The sensitivity of the Parr vision test for detecting ocular conditions in preschool children does not vary significantly from that achieved by the Lea symbols or the Spot vision screener. However, current New Zealand vision screening protocols could be improved by expanding the target conditions to include significant refractive error and incorporating the use of the Spot vision screener to increase the accuracy with which children with refractive error are identified. Future research should include longitudinal studies to determine the effect of preschool vision screening on later ocular and academic outcomes.

Progression From Soft Lens to Piggyback Soft-Scleral Contact Lens System to Facilitate Scleral Lens Use in a Pediatric Patient.

Traumatic injury in the pediatric population often results in significant refractive errors that if left untreated can lead to amblyopia. Scleral contact lenses (ScCLs) have recently gained popularity in this population for efficacy in treatment of significant refractive errors, including irregularity astigmatism and corneal abnormalities. Scleral contact lens intolerance may limit the ability of practitioners to use this modality. Although a soft contact lens (SCL) is generally well tolerated, it cannot treat refractive error as effectively as an ScCL. We recently used an SCL followed by an SCL-ScCL combination ("piggyback" system) sequence in a pediatric patient to facilitate use of an ScCL alone. We hope that our results may provide practitioners with an additional option when treating this challenging patient population.

Visual Status among Nepalese Civilian Pilots

Introduction: Vision assessment is a part of medical examination for pilots. Visual acuity and refraction are performed routinely but binocular vision assessment is rarely performed. The aim of this study was to evaluate the visual status of Nepalese civilian pilots, including binocular vision assessment. Methods: It was a descriptive, cross sectional study conducted among Nepalese pilots. Thirty pilots operating domestic flights and twenty operating international flights, from 7 different airline companies participated in this study. A detailed ophthalmic examination of the pilots was performed by an investigator under the guidance of an Optometrist from January to August 2006. Examinations were conducted at Nepal Airlines Corporation, head office and domestic terminal at Tribhuwan international airport (TIA). The data collected were analyzed to determine presenting visual acuity, refractive error and binocular vision of pilots. Results: Among 50 pilots, 88% of pilots had presenting visual acuity within normal limits (6/6 binocularly) as normal requirement set by Civil Aviation Authority of Nepal (CAAN). Pilots having significant refractive errors were 32%. Other visual symptoms related were present in 16% of pilots. Only one case had intermittent exotropia (IXT) and exophoria was present in 15 (30%) pilots among which 3 (6%) had deviation between 4-8 prism diopters. Conclusion: About 90% of Nepalese civilian pilots had normal visual acuity as defined by civil aviation authority of Nepal (CAAN). However, few pilots had some form of binocular vision disorders which could easily be im3proved by vision therapy.

Epidemiology, clinical profile, and pattern of refractive error in newly diagnosed cases of refractive error in pediatric population visiting a tertiary eye care center

Purpose: This study aimed to evaluate the epidemiology, clinical profile, and pattern of refractive error in newly diagnosed cases in children visiting a tertiary care eye center in southern India. Materials and Methods: This prospective study was conducted on 367 children, ≤15 years of age, with significant refractive error who visited our tertiary eye care hospital over a period of 1 year. Every child underwent detailed ocular examination. Significant refractive error was defined as myopia of ≥−0.75 diopter (D), hypermetropia of more than +2 D, and astigmatism of more than 0.75 D. Descriptive statistics were computed for better and the worse eye. Statistical tests were applied between the worse and better eyes using Chi-square test. Results: A total of 367 children (38.8%) were diagnosed for the first time of having refractive error. Only 146 (39.8%) children presented with visual complaints. With respect to the vision in the worse eye, 65.9% (n = 240) had moderately subnormal vision. There was no statistically significant difference (P = 0.057) between age distribution and visual acuity in the worse eye. Two hundred and thirty-eight children (64.9%) had significant astigmatism as compared to 161 myopic (43.9%) children. There was a statistically significant difference between reasons of visit and different age groups. Conclusions: Astigmatism was the most prevalent refractive error and uncorrected astigmatism the most significant amblyogenic factor. Since majority of children, especially in the younger age group, present with nonvisual complaints, involvement of pediatricians and parents will help us to reduce morbidity due to uncorrected refractive error and amblyopia.

Co-existence of myopia and amblyopia in a guinea pig model with monocular form deprivation.

BackgroundForm deprivation myopia is a type of ametropia, with identifiable causes in humans, that has been induced in many animals. The age of onset of myopia induced by monocular form deprivation coincides with the period of visual development in guinea pigs. However, visual acuity of form-deprived eyes in guinea pigs is not understood yet. In this study, we investigated whether monocular form deprivation would affect visual acuity in infant guinea pigs by evaluating the development of myopia and amblyopia after monocular form deprivation, and whether form deprivation myopia and amblyopia occurred simultaneously or successively.MethodsTwenty pigmented guinea pigs (2 weeks old) were randomly assigned to two groups: monocularly form-deprived (n=10), in which facemasks modified from latex balloons covered the right eye, and normal controls (n=10). Refraction, axial length, and visual acuity were measured at 4 intervals (after 0, 1, 4, and 8 weeks of form deprivation), using cycloplegic streak retinoscopy, A-scan ultrasonography (with an oscillation frequency of 10 MHz), and sweep visual evoked potentials (sweep VEPs), respectively. Sweep VEPs were performed with correction of the induced myopic refractive error.ResultsLonger deprivation periods resulted in significant refractive errors in form-deprived eyes compared with those in contralateral and normal control eyes; the axial lengths of form-deprived eyes increased significantly after 4 and 8 weeks of form deprivation. These results revealed that myopia was established at 4 weeks. The acuity of form-deprived eyes was unchanged compared to that at the pretreatment time point, while that of contralateral eyes and eyes in normal control guinea pigs improved; there were significant differences between the deprived eyes and the other two open eyes from 1 to 8 weeks of form deprivation, showing that amblyopia was possibly established during 1 week of form deprivation.ConclusionsThis study demonstrated the feasibility of using sweep VEPs to estimate the visual acuity of guinea pigs. Further, our results revealed that amblyopia likely occurred earlier than myopia; amblyopia and myopia coexisted after a long duration of monocular form deprivation in guinea pigs. Understanding this relationship may help provide insights into failures of treatment of amblyopia associated with myopic anisometropia.