Spectacle Correction Research Articles

Simultaneous Topography-guided Surface Ablation with Collagen Cross-linking for Keratoconus

ABSTRACT Purpose In this article, we present the results of eight eyes of patients who underwent combined same-day partial topography-guided surface ablation followed by accelerated collagen cross-linking (CXL) procedure at Care-Vision Laser Centers to achieve stabilization of corneal ectasia and enhance visual rehabilitation in keratoconus. Materials and methods A retrospective nonrandomized review of 8 eyes of 6 patients who underwent the Athens Protocol for progressive keratoconus. Each patient underwent topography-guided ablation followed by CXL procedure. Follow-up Follow-up was done on day 1, day 7, and then at 1, 3, 6, and 12 months. Results There was a rapid and significant improvement in uncorrected visual acuity and best-corrected visual acuity in 100% eyes, a reduction of keratometric values, and symmetry between vertical hemimeridians. Topographic evaluation showed a marked improvement in irregularity. There were no signs of keratoconic progression noted in any of the eyes on last follow-up. No adverse events were reported in any patient. Conclusion Simultaneous surface ablation + CXL seems to be a promising treatment capable of offering patients functional vision and halting progression of the disorder. Precis Simultaneous topography-guided custom ablation treatment and photorefractive keratectomy with CXL offers keratoconic patients intolerant to contact lenses both stabilization of the cornea and improved functional vision with spectacles correction. How to cite this article Karmona L, Sela T, Franco O, Shoshani A, Munzer G, Kaiserman I. Simultaneous Topography-guided Surface Ablation with Collagen Cross-linking for Keratoconus. Int J Kerat Ect Cor Dis 2016;5(2):71-76.

Posteriorly dislocated/subluxated cataractous lens: A surgical dilemma and management

Aim: To assess and compare the visual outcome of the different approaches in the management of dislocated/subluxated cataractous lens. Methods: This is a retrospective study of 32 eyes of 32 patients who were managed for dislocation/subluxation of cataractous lenses from 2012 to 2015. All patients underwent 3PPPV/ anterior vitrectomy with PFCL assisted extraction of the dislocated cataractous lens. 2 point ab-externo scleral fixated IOLs were implanted in 15 patients, ACIOL implantation was done in 2 patients and the remaining 15 patients who underwent Vitrectomy and lens removal were left aphakic due to various reasons (a)lost to follow up (b)fellow eye aphakic(c)had preoperative complications like Vitreous haemorrhage, Retinal break etc. The visual outcome of these various procedures were compared and analysed. Results: Our study included 32 eyes of 32 patients with a median follow up period ranging from 3-36 months. SFIOLs were implanted in 15 patients, ACIOL implantation was done in 2 patients and 15 patients were left aphakic. Post-operative best corrected visual acuity of 6/18 or better was achieved in 73.33% of patients treated with SFIOL implantation. BCVA of 6/18 or better was achieved in 40% of patients who were left aphakic and given aphakic spectacle correction. The remaining 60% had a visual acuity of

A comparative study of the efficacy of part time occlusion and full time occlusion therapy in moderate and severe Amblyopia in children and factors influencing the outcome

Aims: A comparative study of the efficacy of full time occlusion and part time occlusion therapy in moderate and severe Amblyopia, to establish the dose-response relationship between occlusion therapy and improvement in visual acuity, and how this is modified by patient characteristics. Methods: This is a prospective study including 44 amblyopic patients aged 5-10 years, who were initially given one month of spectacle correction. Four patients lost to follow up and remaining 24 patients were prescribed part time occlusion while 16 patients were given full time occlusion. Subsequently they were followed at 1 week, 2 week, 4 week, 8 week and 12 week intervals. Result: The mean age of study population was 7.2±1.8 years with 60% male and 40% of female. In part occlusion therapy average line of improvement was 1.08±0.51 lines while in full time occlusion therapy improvement was 1.25±0.70 lines and the difference among these groups was not statistically significant (p value 0.53). Conclusion: Part time occlusion is comparable to full-time occlusion in effectiveness of treatment in moderate and severe Amblyopia. Prescribing fewer hours of daily patching may ease the implementation of patching therapy and monitoring of compliance for parents. Key words: Amblyopia, Occlusion therapy, Full-time occlusion, Part-time occlusion

Uso de toxina botulínica A en el tratamiento de las endotropías parcialmente acomodativas

ObjectiveTo determine the effectiveness of a botulinum toxin type A injection in both medial rectus muscles in patients with partially accommodative esotropia. Residual deviation and stability of strabismus were evaluated at 18 months follow up. MethodA prospective, analytical, quasi-experimental study was conducted on a cohort of 21 patients who underwent total cycloplegic refraction and with a residual deviation of at least 14 DP. A botulinum toxin type A dose of 5 IU was injected into each medial rectus muscle for a residual deviation greater than 18 DP, with a dose of 2.5 IU being used for a deviation between 14 and 18 DP. Multivariate logistic regression analyses were performed to relate residual deviation to variables recorded as potential predictors. ResultsA total of 21 patients were included, 33.3% (n=7) males and 66.6% (n=14) females. Mean visual acuity was –.28±.25 logMAR for right eye (range 0 to –1) and –.42±.31 logMAR for left eye (range 0 to –1.3). Mean angle of residual deviation before application of botulinum toxin was 40.95±8.6DP without spectacles correction, and 22.3±7.99 DP with full cycloplegic refraction. Adverse effects were ptosis in 14.2% (n=3), diplopia 23.8% (n=5), and vertical deviation in 33% (n=7). One patient had a poor outcome, therefore required surgical treatment.At one year follow up, 85.71% of patients showed good results with esotropia of 12 DP or less, dropping to 71.43% at 18 months of follow up. ConclusionBotulinum toxin type A is an effective long–term treatment with a good response in 71.43% of patients. No predictors of good response were demonstrated.

Penggunaan Lensa Kontak untuk Astigmatisma Paska Keratoplasti

Background: Fitting Contact Lenses for post penetrating keratoplasty patiens can be a great challenges to contact lens practitioner. Despite advances in surgical techniques for penetrating keratoplasty, post- operative ametropia and high irregular astigmatism still remain common. Patients who have such those problems may need contact lenses to achieve optimal vision.Case Illustration: Case 1. A 12 years old boy have a high myop and astigmatism after undergone penetrating keratoplasty combined with traumatic cataract extraction and IOL implantation. His right eye vision was 6/24 with corrections of S – 8.00 C – 6.50 x 150. His right eye was fitted with RGP contact lens with Base curve of 7.20 mm, Power of – 10.25 D, and diameter of 8.80 mm. His RE vision with RGP contact lens was 6/12; Case 2. Female, 18 years old, was diagnosed with compound high myopia astigmatism of right eye due to disfigured cornea post keratoplasty and high astigmatism of the left eye due to corneal scar. Piggyback contact lens system is then used to treat her right eye.The patient’s uncorrected visual acuity on the right eye was half meter counting finger, became 6/40 with spectacle and 2 meters counting finger became 3/60 with spectacle on the left eye. With piggyback contact lens consisting of soft contact lens 8.60/-10.00/14.20 and RGP lens 7.20/-4.00/8.8 on the right eye, and RGP lens 7.90/-5.00/9.2 on left eye, her visual acuity became 6/12 on her right eye became 6/9 on the left eye.Conclusion: Rigid gas-permeable and combination of rigid gas permeable and soft contact lenses can be fitted with piggy-back system successfully in patients unable to achieve optimal vision with spectacle correction after penetrating keratoplasty

Predictive Value of Headache for Screening of Refractive Errors in the Pediatric Age Group

This article aims to study the predictive value of headache for screening of refractive errors in the pediatric age group. This is a cross-sectional study conducted in the outpatient setting of the Department of Ophthalmology of Lala Lajpat Rai Hospital, associated with Ganesh Shanker Vidyarthi Memorial Medical College, Kanpur (India), during a period of 1 year, including 5,398 children in the age group of 5 to 15 years. Data were collected using a predesigned, pretested questionnaire which included demographic data and chief complaints. All the subjects underwent visual acuity and refractive error testing. Visual acuity was conducted using Snellen's chart and Landolt's C chart. Thereafter, refractive testing was done under cycloplegia and corrective spectacles were prescribed to the patient. Data were analyzed using statistical package for social sciences version 16.0. Chi-square test was applied to analyze the discrete variables. Data were also used to calculate the sensitivity, specificity, positive predictive value, and negative predicative value of headache as a screening tool for the predicting refractive errors in children. Twelve percent of the total population attending the ophthalmic outpatient department belonged to the age group of 5 to 15 years. The male:female ratio was 1.3:1. Out of the total, 58.8% of the subjects had refractive errors. Myopia was the most common refractive error (46.4%) followed by astigmatism (31.3%) and then hyperopia (22.3%). Gender difference was significant (p

Efficacy, Safety and Acceptability of Orthokeratology on Slowing Axial Elongation in Myopic Children by Meta-Analysis

Purpose: To compare the efficacy, safety and acceptability of a treatment group (Orthokeratology) to a control group (single vision Spectacles) on slowing axial elongation in children.Methods: We searched studies in MEDLINE, EMBASE and the Cochrane Library up to January 2015 for randomized controlled trials (RCTs) and observational studies. We pooled the mean differences between the Orthokeratology and Control groups for axial elongation and the OR for rates of adverse events and dropout.Results: Three RCTs and six cohort studies with 667 children aged 6–16 years old were included. Two years’ mean differences in axial elongation were −0.27 mm (95% confidence intervals [CI], −0.32 to −0.23) in all studies, −0.28 mm (95% CI, −0.35 to −0.20) in RCTs and −0.27 mm (95% CI, −0.32 to −0.22) in cohort studies (p < 0.01). At 6 months, 1 year, 1.5 years and 2 years, mean differences in axial elongation were −0.13 mm, −0.19 mm, −0.23 mm, and −0.27 mm (p < 0.01), respectively. The effect was greater in Asian children than Caucasian (−0.28 mm versus −0.22 mm) and in children with moderate to high myopia when compared to children with low myopia (−0.35 mm versus −0.25 mm). Orthokeratology had more non-significant adverse events (odd ratio [OR], 8.87; 95% CI, 3.79–20.74; p < 0.01) but comparable dropout rates (OR = 0.84, 95% CI, 0.40–1.74, p = 0.64) than control.Conclusion: Orthokeratology has significantly greater efficacy in controlling axial elongation in children compared to Spectacle correction. The safety and acceptability results are good, and there appears to be a greater myopia control effect in Chinese children compared to Caucasians, and in those with higher initial myopia.

Stereoacuity in children with accommodative esotropia versus partially accommodative esotropia

• Accommodative esotropia was defined as > 10 PD of intermittent or constant esotropia. • Fully accommodative esotropia (FAET) was diagnosed in those children having 4 weeks and maintaining such alignment for > one year. • Partially accommodative esotropia (PAET) was diagnosed in those children with 10 PD or more residual ET after wearing their full hyperopic spectacle correction for > 4 weeks. • Stereoacuity was tested with the fly and circles on the Stereo Fly Test (Stereo Optical Co., Inc.) at 40 cm.

Overminus spectacle correction in the management of intermittent exotropia

We sought to determine the effectiveness of prescribing over-minus spectacle correction in the management of intermittent exotropia.

The status of refractive errors in elementary school children in South Jeolla Province, South Korea

Purpose: To assess the prevalence of refractive errors among elementary school children in South Jeolla Province of South Korea. Methods: The subjects were aged 8–13 years; a total of 1,079 elementary school children from Mokpo, South Jeolla Province, were included. In all participants, uncorrected visual acuity and objective and subjective refractions were determined using auto Ref-Keratometer and phoropter. A spherical equivalent of -0.50 diopter (D) or worse was defined as myopia, +0.50 D or more was defined as hyperopia, and a cylinder refraction greater than 0.75 D was defined as astigmatism. Results: Out of 1,079 elementary school children, the prevalence of uncorrected, best-corrected, and corrected visual acuity with own spectacles of 20/40 or worse in the better eye was 26.1%, 0.4%, and 20.2%, respectively. The uncorrected visual acuity was 20/200 or worse in the better eye in 5.7% of school children, and 5.2% of them already wore corrective spectacles. The prevalence of myopia, hyperopia, and astigmatism was 46.5% (95% confidence interval [CI]: 43.56–49.5), 6.2% (95% CI: 4.92–7.81), and 9.4% (95% CI: 7.76–11.25), respectively. Conclusion: The present study reveals a considerably higher prevalence of refractive error among elementary school children in South Jeolla Province of South Korea, exceeding 50% of subjects. The prevalence of myopia in the school children in Korea is similar to many other countries including People’s Republic of China, Malaysia, and Hong Kong. This may indicate that genetics and educational influences, such as studying and learning, may play a role in the progression of myopia in Korean elementary school children.

Prevalence of presbyopia and spectacle correction coverage in a rural population of North West Nigeria.

PurposeTo determine the prevalence of presbyopia, and near vision spectacle coverage in a rural population of Northwestern Nigeria.Study designCross sectional prevalence study.Subjects and methodsSix hundred and fifty people of at least 40 years of age, in 13 clusters (50 per cluster) were examined using a multi-stage random sampling with probability proportional to size. The survey was conducted from April 7 to 28, 2012 at Bungudu Local Government Area of Zamfara State, Nigeria. Presbyopia was defined as the inability to read N8 at 40 cm. Presbyopic Spectacle Correction Coverage (PSCC) was calculated, and information on barriers to using near vision spectacles identified.ResultsThe crude prevalence of presbyopia was 30.4%, 95% CI: (26.8%–34.1%). The prevalence was significantly higher in females (P=0.0005) and individuals with at least secondary education (P=0.022). The age specific prevalence of presbyopia was three times (63.5%) more among those aged 70 years and above, as compared to those within 40–49 years age group (19.3%). The met need was 0.2%, the unmet need 30.2%, and a PSCC of 0.7%. The major barriers reported as reasons for not obtaining near vision spectacles were unawareness and lack of felt need.ConclusionThe prevalence of presbyopia in Bungudu is relatively low compared to other reports with major risk factors being increasing age, female sex and attainment of higher education. The presbyopic spectacles correction coverage is very low with high unmet need thus there is a need to create awareness, and provide affordable and accessible optical services in the affected population.

Visual impairment attributable to uncorrected refractive error and other causes in the Ghanaian youth: The University of Cape Coast Survey

PurposeTo determine the prevalence of visual impairment attributable to refractive error and other causes in a youthful Ghanaian population. MethodsA prospective survey of all consecutive visits by first-year tertiary students to the Optometry clinic between August, 2013 and April, 2014. Of the 4378 first-year students aged 16–39 years enumerated, 3437 (78.5%) underwent the eye examination. The examination protocol included presenting visual acuity (PVA), ocular motility, and slit-lamp examination of the external eye, anterior segment and media, and non-dilated fundus examination. Pinhole acuity and fundus examination were performed when the PVA≤6/12 in one or both eyes to determine the principal cause of the vision loss. ResultsThe mean age of participants was 21.86 years (95% CI: 21.72–21.99). The prevalence of bilateral visual impairment (BVI; PVA in the better eye ≤6/12) and unilateral visual impairment UVI; PVA in the worse eye ≤6/12) were 3.08% (95% CI: 2.56–3.72) and 0.79% (95% CI: 0.54–1.14), respectively. Among 106 participants with BVI, refractive error (96.2%) and corneal opacity (3.8%) were the causes. Of the 27 participants with UVI, refractive error (44.4%), maculopathy (18.5%) and retinal disease (14.8%) were the major causes. There was unequal distribution of BVI in the different age groups, with those above 20 years having a lesser burden. ConclusionEye screening and provision of affordable spectacle correction to the youth could be timely to eliminate visual impairment.

A Test for Progressive Myopia and the Role of Latent Accommodation in its Development

Purpose: To determine whether those myopes who respond like hyperopes when tested with a multivergence hologram are progressive myopes and to investigate the role of latent accommodation in the development of progressive myopia. Methods: Recently, we introduced a specially designed hologram to test the vision of spectacle corrected subjects. A subject viewing through this hologram would see the real and virtual images of different test letters at various distances. We observed that some of the myopes responded like hyperopes in that test. The current study is designed to see if these myopes were progressive myopes. Using data on the spectacle correction measured initially and in later years for the myopes who participated in our studies with the hologram, we calculate the progression rate of myopia. Using progression rate, subjects are classified into progressive and non-progressive myopes. We analyse the data obtained for these subjects in the test with the hologram and propose a test for progressive myopia. We also investigate the role of latent accommodation in the measurement of low ametropia and the development of progressive myopia. Results: We found that the myopes who respond like hyperopes in the test with the hologram are progressive myopes! Based on this result we propose a test for progressive myopia. Our initial results show that the test has a sensitivity of 54% and a specificity of 100%. Our studies indicate that progressive myopes have some latent accommodation like hyperopes and progressive myopia may be a consequence of incorrect diagnosis/correction of low hyperopia/ myopia brought about by the play of latent accommodation.

Postkeratoplasty Astigmatism

The success of penetrating keratoplasty in terms of graft survival is excellent but visual rehabilitation continues to be a significant issue primarily due to astigmatism. Factors contributing to postoperative astigmatism can be related to preoperative etiology, suturing techniques and the postoperative healing process and timing of surgery. The large number of options available to address postoperative astigmatism only serves to highlight the complex nature of the problem. This review offers an up-to-date account of the various options available to manage postkeratoplasty astigmatism. Spectacles and rigid gas-permeable (RGP) contact lenses offer the earliest and easiest forms of visual rehabilitation. Spectacle correction may be limited by astigmatic anisometropia. Rigid gas-permeable contact lenses are an effective alternative to spectacles but limited by fitting and handling issues. Suture adjustment and suture removal are the initial options for reducing postoperative astigmatism. Careful attention to suture techniques intraoperatively and timely removal of appropriate sutures in the postoperative period can decrease astigmatism to tolerable levels. For the management of residual astigmatism after suture removal, a plethora of choices exist. Relaxing incisions, astigmatic keratotomy, compression sutures and wedge resections are well explored techniques offering effective but unpredictable results. Photorefractive keratectomy and laser in situ keratomileusis are newer options available to correct both spherical and astigmatic errors, but outcomes are variably affected by the healing process. The current availability of phakic and toric intraocular lenses has also been explored for the correction of postkeratoplasty astigmatism with promising results. Intra-corneal ring segments used for the management of astigmatism in keratoconus finds a new application in postkeratoplasty astigmatism. The femtosecond laser has opened up ways to perform procedures such as astigmatic keratotomy, the placement of intra-corneal ring segments, and creation of flaps for laser in situ keratomileusis, with very good precision and accuracy.

Brief Report: A Hypothetical Construct Based on Limited Data Visual System Recovery After Refractive Surgery

Laser refractive surgery, involving the computer-controlled application of a 193-nm beam of excimer laser "light," is utilized to resculpt the central cornea, thus reducing its apical thickness. On casual inspection, this simple matter of removing or excising a specific amount of central corneal avascular tissue is a smooth, seamless alteration with few apparent secondary issues or sequelae. Normal postoperative recovery is typically gauged by the recovery of high-contrast visual acuity to the same (or better) degree as was previously obtained with a spectacle correction. However, although this is an acceptable means of determining operative success, it is not indicative of the complex challenges imposed upon the neurosensory system. The secondarily imposed strain upon the visual system, regarding the return to its pre-existing visual line-of-sight organization occurs only by bringing multiple adaptations into subtle and seamless play. This process is initiated and completed in a relatively short time period, such that most patients (but not all) are not even marginally aware of the challenges imposed to the visual system. This article is meant to probe those system challenges, serving to highlight this postoperative plasticity, seeking to gain a broader understanding and appreciation of the perceptual range of the visual recovery process.

Stereoacuity changes after laser in situ keratomileusis.

To study changes in near and distance stereoacuity after laser in situ keratomileusis (LASIK). A prospective interventional study was conducted at an apex tertiary care ophthalmology center in India. Near and distance stereoacuity was tested in 40 patients (80 eyes) who underwent LASIK for myopic correction and got unaided vision of 0.67 or better in each eye. Stereoacuity was tested with best spectacle correction before LASIK, and post-LASIK stereoacuity was tested with unaided eye near and distance Randot tests. Forty patients (80 eyes) had a mean (±SD) pre-LASIK refractive error of -4.70 (±1.72) DS OD and -4.59 (±1.58) DS OS and a mean (±SD) anisometropia of 0.55 (±0.51) DS. The median pre-LASIK near stereoacuity was 70 arcsec and distance stereoacuity was 200 arcsec, both of which improved after LASIK to 30 and 60 arcsec, respectively (p < 0.001, both). Amount of refractive error was not associated with stereoacuity but anisometropia of greater than or equal to 1 diopter had significantly worse distance stereoacuity in both the pre-LASIK and post-LASIK period. The post-LASIK near stereoacuity and distance stereoacuity were strongly associated (r = 0.706, p < 0.001) unlike the change in stereoacuity. Near and distance stereoacuity shows significant improvement after LASIK. Stereoacuity is associated with the degree of anisometropia but not the amount of refractive error corrected.

Prevalence of refractive error, presbyopia and spectacle coverage in Kahama District, Tanzania: a rapid assessment of refractive error

BackgroundIn Tanzania, the prevalence of refractive error and presbyopia have not been comprehensively assessed, limiting appropriate planning and implementation of delivery of vision care. This study sought to determine the prevalence of refractive error and presbyopia, spectacle coverage and the barriers to uptake of refractive services in people aged 15 years and older in the Kahama district of Tanzania.MethodsA cross‐sectional community‐based survey was conducted using 54 randomly selected clusters. Respondents 15 years and older were interviewed and underwent standardised clinical eye examinations. Uncorrected refractive error (URE) was defined as presenting vision worse than 6/12 that could be corrected to better than 6/12 using a pinhole. Spectacle coverage was defined as the proportion of need that was met (those that improved from unaided vision with their own spectacle correction).ResultsA total of 3,230 subjects (99.75 per cent of 3,240 eligible) participated in the study with 57.2 per cent males and the median age of participants was 35 years (inter‐quartile range, 24 to 49). The prevalence of visual impairment was 10.4 per cent (95% CI 9.4 to 11.4) and was lower in those who had completed their primary school education (odds ratio (OR) 0.54, 95% CI: 0.40 to 0.72) and highest in subjects 40 years and older (OR 3.17, 95% CI: 2.14 to 4.70) and farmers (OR 8.57 95% CI: 2.27 to 32.43). Refractive error prevalence was 7.5 per cent (95% CI: 6.65 to 8.54) and this was highest in participants over 40 years (OR 1.60, 95% CI: 1.14 to 2.25) and in students (OR 3.64, 95% CI: 1.35 to 9.86). Prevalence of presbyopia was 46.5 per cent (773/1,663, 95% CI: 44.34 to 48.75). Spectacle coverage for refractive error and presbyopia was 1.69% (95% CI: 0 to 3.29) and 0.42% (95% CI: 0 to 1.26), respectively.ConclusionUncorrected refractive error is a public health challenge in the Kahama district and sustainable service delivery and health promotion efforts are needed.

Evaluating the cost effectiveness of national program for control of blindness in Jorhat district, India.

Background:We evaluated the cost of different components of the national program for control of blindness (NPCB) and assess the cost effectiveness of this program.Materials and Methods:An observational study was conducted in Jorhat District of Assam, India from July 2009 to June 2010 for assessing the cost effectiveness of the NPCB. Four broad categories of cost inputs, that is, capital costs, recurrent costs, prime/variable costs, and fixed costs were considered. The cost incurred by the provider was taken as the actual cost of delivery of different component of services to the patients, which was calculated from the costs of labor, material, and capital costs using the time utilization pattern recommended by WHO.Result:The District Blindness Control Society, Jorhat had spent 58.93% of total expense on fixed heads of which 65.86% had been spent for cataract surgery. The medical care cost was found to be Indian rupee (INR) 425 for intracapsular cataract extraction (ICCE), INR 675 for extracapsular cataract extraction + intraocular lens (ECCE + IOL) and INR 225 for refractive error correction. The patient-wise provider cost was estimated to be INR 519 for ICCE, INR 769 for ECCE + IOL implantation and INR 319 for spectacle correction of refractive error.Conclusion:National program for control of blindness is a cost effective means of controlling and treating blindness.

Changes in refractive errors related to spectacle correction of hyperopia.

BackgroundHyperopic undercorrection is a common clinical practice. However, less is known of its effect on the change in refractive errors and emmetropization throughout the later years of childhood.ObjectivesTo evaluate the effect of spectacle correction on the change in refractive errors in hyperopic children less than 12 years of age with or without strabismus.Data ExtractionA retrospective cohort study was performed by a computer based search of the hospital database of patients with hyperopia, accommodative esotropia or exotropia. A total of 150 hyperopic children under 12 years of age were included. Patients were classified into four groups: 1) accommodative esotropia with full correction of hyperopia, 2) exotropia with undercorrection of hyperopia, 3) orthotropia with full correction of hyperopia, 4) orthotropia with undercorrection of hyperopia. The 4 groups were matched by initial age on examination and spherical equivalent refractive errors (SER). The main outcome measure was the change in SER (Diopter/year) in both eyes after two years of follow-up.ResultsAn overall negative shift in SER was noted during the follow-up period in all groups, except for the group with esotropia and full correction. The mean negative shift of hyperopia was more rapid in groups receiving undercorrection of hyperopia with or without strabismus. The amount of undercorrection of hyperopia was positively correlated to the magnitude of decrease in hyperopia in all patients (r = 0.289, P<0.001) and in the subgroup of patients with orthotropia (r = 0.304, P = 0.011). The amount of undercorrection of hyperopia was the only factor associated with a more negative shift in SER (OR, 2.414; 95% CI, 1.202–4.849; P = 0.013).ConclusionsThe amount of undercorrection is significantly correlated to the change in hyperopic refractive errors. Full correction of hyperopia may inhibit emmetropization during early and late childhood.

Prevalence of refractive error and visual impairment among rural school-age children of Goro District, Gurage Zone, Ethiopia.

Refractive error is one of the major causes of blindness and visual impairment in children; but community based studies are scarce especially in rural parts of Ethiopia. So, this study aims to assess the prevalence of refractive error and its magnitude as a cause of visual impairment among school-age children of rural community. This community-based cross-sectional descriptive study was conducted from March 1 to April 30, 2009 in rural villages of Goro district of Gurage Zone, found south west of Addis Ababa, the capital of Ethiopia. A multistage cluster sampling method was used with simple random selection of representative villages in the district. Chi-Square and t-tests were used in the data analysis. A total of 570 school-age children (age 7-15) were evaluated, 54% boys and 46% girls. The prevalence of refractive error was 3.5% (myopia 2.6% and hyperopia 0.9%). Refractive error was the major cause of visual impairment accounting for 54% of all causes in the study group. No child was found wearing corrective spectacles during the study period. Refractive error was the commonest cause of visual impairment in children of the district, but no measures were taken to reduce the burden in the community. So, large scale community level screening for refractive error should be conducted and integrated with regular school eye screening programs. Effective strategies need to be devised to provide low cost corrective spectacles in the rural community.