logMAR Chart Research Articles

Evaluating the effect of cataractous vision on the general characteristics of handwriting: its forensic implications

Abstract Purpose To evaluate any effect of cataractous vision on handwriting performance. Methods Nine patients were enrolled for Phase I with an average age of 75 yrs (range: 69 to 84 yrs). Visual acuity (VA) was evaluated using the European‐wide logMAR charts for far, intermediate and near vision. Measurements were performed pre‐operatively and three‐ months post‐operatively, with habitual correction, under both monocular and binocular viewing conditions. Patients were asked to give signature and handwriting samples at each visit. The signatures were compared, focusing on the general characteristics of line quality, general design, size, arrangement, spacing, slant and their sub‐elements. Results Average monocular and binocular VA was found to improve at all measured distances post‐operatively. E.g., average binocular intermediate acuity increased from 0.52 (±0.29) to 0.20 (±0.24) logMAR, while near acuity increased from 0.70 (±0.33) to 0.52 (±0.17) logMAR. The forensic analysis showed that cataractous vision tends to influence some general characteristics, eg decreasing the line quality of the allographs and creating significant dissimilarity on the size sub‐elements. On average, the general characteristics of general design, intra‐allograph ratio and slant were not influenced by the compromised vision. A number of "non liquet" results were manifested, caused by the complete differentiation of the structure of certain allographs before and after the cataract surgery. Conclusion Cataractous vision compromises some handwriting characteristics. Future research will focus on quantifying and exporting the results to the general population.

A comparison of the effect of 3M Fresnel prisms and Trusetal prism foils on visual function

Aim: To determine any differences in visual acuity (VA) and contrast sensitivity (CS) between 3M Fresnel prisms and Trusetal prisms foils. Methods: Sixteen participants (mean age 20 years) with normal VA and CS participated. The effect of 5 Δ , 10 Δ , 20 Δ and 30 Δ prism strengths on monocular VA and CS was assessed using a Bailey-Lovie logMAR chart and Pelli-Robson chart, respectively. Measurements were carried out for both 3M Fresnel prisms and Trusetal prism foils. A comparison of the physical properties of the two prism types was made. Results: Deterioration in VA and CS was evident with increasing prism strength with both prism types. VA was more significantly reduced with 3M Fresnel prisms than with Trusetal prism foils [F1,15 = 19.63, p < 0.001]. There was significant interaction between prism types and prism strength [F3,45 = 10.36, p < 0.0001], due to 30 Δ 3M Fresnel prisms reducing VA by 0.13 logMAR more than the Trusetal prism foils. There was no statistically significant difference between the prism types for CS [F1,15 = 2.21, p = 0.1582]. 3M Fresnel prisms were thinner than the Trusetal prism foils. The thicker Trusetal prism foils consist of fewer bases per centimetre but were more difficult to fit to spectacle lenses. Conclusions: There is no difference in VA or CS regardless of whether a 3M Fresnel prism or Trusetal prism foil is used until 30 Δ , when Trusetal prism foils give better VA. For large deviations it may therefore be more beneficial for the patient to use a Trusetal prism as part of their treatment plan.

Evidence that children with special needs all require visual assessment

DesignA protocol-based ophthalmological assessment was performed on-site by a skilled investigator.PatientsChildren attending schools for special needs in Glasgow were offered eye care within their school. Outcomes for the first 240...

Use of Visual Acuity to Screen for Significant Refractive Errors in Adolescents

To detect significant refractive error in a population-based random cluster sample of 12-year-old schoolchildren by using sensitivity and specificity of uncorrected visual acuity (VA). The Sydney Myopia Study randomly selected 21 secondary schools stratified by socioeconomic status. All year 7 students (mean age, 12.7 years) were invited to participate. We tested VA monocularly, unaided at 2.44 m, using a retroilluminated logMAR chart. Cycloplegic autorefraction (induced with instillation of cyclopentolate hydrochloride, 1%) was used to define clinically significant refractive error as a spherical equivalent of -1.00 diopters (D) or less for myopia; at least +2.00 D for hyperopia; and -1.00 D or less cylinder power for astigmatism. Data for both eyes were pooled for a total of 4497 observations. The sensitivity and specificity for all clinically significant refractive errors at the best VA cutoff level of 53 letters (6/6(-2)) were 72.2% and 93.3%, respectively. Myopia had the highest sensitivity and specificity of any of the refractive errors for detection using VA (97.8% and 97.1%, respectively, for a 45-letter VA cutoff [6/9.5]). The best VA cutoffs for hyperopia and astigmatism were 57 (6/6(+2)) and 55 (6/6) letters, respectively, with sensitivities of 69.2% and 77.4%, respectively, and specificities of 58.1% and 75.4%, respectively. In this adolescent group, a VA cutoff of 6/9.5 or less detects myopic refractive error reliably. However, there is no reliable VA cutoff for clinically significant hyperopia or astigmatism. Improved VA screening methods are required to improve detection of these conditions. Even so, with the methods described herein, the prevalence of uncorrected VA may provide a reasonably accurate estimate of the prevalence of myopia.

Prevalence of Amblyopia and Strabismus in Young Singaporean Chinese Children

PURPOSE. To determine the prevalence of amblyopia and strabismus in young Singaporean Chinese children. METHODS. Enrolled in the study were 3009 Singaporean children, aged 6 to 72 months. All underwent complete eye examinations and cycloplegic refraction. Visual acuity (VA) was measured with a logMAR chart when possible and the Sheridan-Gardner test when not. Strabismus was defined as any manifest tropia. Unilateral amblyopia was defined as a 2-line difference between eyes with VA < 20/30 in the worse eye and with coexisting anisometropia (> or =1.00 D for hyperopia, > or =3.00 D for myopia, and > or =1.50 D for astigmatism), strabismus, or past or present visual axis obstruction. Bilateral amblyopia was defined as VA in both eyes <20/40 (in children 48-72 months) and <20/50 (<48 months), with coexisting hyperopia > or =4.00 D, myopia < or = -6.00 D, and astigmatism > or =2.50 D, or past or present visual axis obstruction. RESULTS. The amblyopia prevalence in children aged 30 to 72 months was 1.19% (95% confidence interval [CI], 0.73-1.83) with no age (P = 0.37) or sex (P = 0.22) differences. Unilateral amblyopia (0.83%) was twice as frequent as bilateral amblyopia (0.36%). The most frequent causes of amblyopia were refractive error (85%) and strabismus (15%); anisometropic astigmatism >1.50 D (42%) and isometropic astigmatism >2.50 D (29%) were frequent refractive errors. The prevalence of strabismus in children aged 6 to 72 months was 0.80% (95% CI, 0.51-1.19), with no sex (P = 0.52) or age (P = 0.08) effects. The exotropia-esotropia ratio was 7:1, with most exotropia being intermittent (63%). Of children with amblyopia, 15.0% had strabismus, whereas 12.5% of children with strabismus had amblyopia. CONCLUSIONS. The prevalence of amblyopia was similar, whereas the prevalence of strabismus was lower than in other populations.

Visual defects in Nepalese children with Down syndrome

Background: Down syndrome (DS) is a common chromosomal anomaly. People with this syndrome have recognisable physical characteristics and limited intellectual abilities. The aim of this study was to determine visual defects, especially refractive error and binocular anomalies, in a sample of Nepalese children with DS.Methods: Thirty‐six children with DS (19 boys and 17 girls) from the Kathmandu valley, aged from four months to 18-years, underwent detailed optometric examination. Cycloplegic refraction was performed on all subjects. Vision on presentation of all the children was assessed with preferential looking cards, the Kay picture cards, the Bailey‐Lovie logMAR chart or the Snellen chart. Binocular function was assessed with cover test, Hirschberg or Bruckner test.Results: Cycloplegic refraction of the children revealed that 80 per cent of the children had significant refractive error. Most of them had hyperopia (55 per cent), followed by astigmatism (44 per cent), myopia (25 per cent) and anisometropia (19 per cent). Only two (5.6 per cent) children were strabismic and both of them were alternating esotropes. Nystagmus was present in 10 (28 per cent). Other ocular findings were upward slanting palpebral fissures, blepharitis, congenital nasolacrimal duct obstruction, blepharoconjunctivitis, chalazion and lenticular opacities.Conclusion: Nepalese children with DS have a high prevalence of refractive error and nystagmus. Regular eye examinations are indicated for these children to enable early diagnosis and appropriate management of ocular disorders to improve their vision and quality of life.

Effect of letter separation on computerised visual acuity measurements: comparison with the gold standard Early Treatment Diabetic Retinopathy Study (ETDRS) chart

Contour interaction plays an important role in letter recognition and has long been known to influence clinical visual acuity measurements. LogMAR charts originally employed between-letter and line spacing of one letter width/height; however, in more recent designs, half letter width spacing has become accepted without validation. COMPlog is a computerised visual acuity measurement device being developed and validated for routine and research clinical use and is available commercially. This study was performed to investigate the effect of letter separation on computerised visual acuity measurements. An iterative series of experiments was performed in which test and retest fully interpolated five letters-per-line logMAR visual acuity measurements were taken in three groups of a total 100 adult subjects. Each group had visual acuity measured using ETDRS charts 1 and 2 and on COMPlog using various combinations of letter and line spacing. The first group consisted of 31 subjects tested using 3.75 and 2.50 stroke width spacing, the second 45 subjects using 2.50 and 1.25 stroke width spacing and the last group, 24 subjects tested using 1.90 stroke width spacing. The methods of Bland and Altman were used to analyse the data. No significant bias was noted between the gold standard ETDRS measurements and those taken using COMPlog with 3.75 stroke width spacing. Significant bias of half a logMAR line was found with crowding of 1.90 and 1.25 stroke widths. A small systematic bias with a reduction of 1 ETDRS letter was found with spacing of 2.50 stroke widths which has not been demonstrated in previous validation studies. Crowding of 2.50 stroke widths is the smallest spacing which can be used in the design of COMPlog.

Eye and vision defects in under-five-year-old children in Oman: A public health intervention study

Purpose:To identify under-five-year-old children with vision or ocular defect in two provinces (Wilayats) of central Oman in 2006.Study Design:Public health intervention study.Materials and Methods:Ocular examination in Manah Wilayat was conducted by nursing staff of the primary health center (PHC) and in Mudhaiby Wilayat was conducted by a trainee Omani optometrist. Abnormal sized eyeball, strabismus, nystagmus and white pupil were recorded. Visual acuity was tested by LOGMAR chart with Lea's symbols in children >2 years of age and preferential viewing was assessed by Lea's grating paddle or 'Hiding Heidi' picture in children ≤2 years age. Data was analyzed using Statistical Package for Social Studies (SPSS 12).Result:Among 1,520 examined children, three children had absent eyeball bilaterally and three had unilaterally absent eyeball. Strabismus and nystagmus were detected in 44 (2.9%) and 18 (1.2%) children respectively. 'Hiding Heidi' test was normal in 530/537 (87%) of children. Distant vision reading was ≥0.32 in 386/448 (86.2%) eyes. Preferential looking test suggested that half of the children had defective vision (>2cpcm). Screening at '1-2 year' and '3-4 years' age group could significantly predict eye problems (P ≤ 0.001).Conclusion:Eye and vision screening of under-five kids helped in detection of eye problems in early stages. Instead of universal screening, high risk population or children of '3 to 4' years for vision and '1 to 2' years for ocular abnormalities is proposed The existing health services could not detect some children with eye problems and they were identified during such screening.

Uncorrected Refractive Errors, Presbyopia and Spectacle Coverage: Results from a Rapid Assessment of Refractive Error Survey

To investigate the prevalence of uncorrected refractive errors, presbyopia and spectacle coverage in subjects aged 15-50 years using rapid assessment methodology in the Mahabubnagar district of Andhra Pradesh, India. A population-based cross sectional study was conducted using cluster random sampling to enumerate 3,300 subjects from 55 clusters. Unaided, aided and pinhole visual acuity was assessed using a LogMAR chart at a distance of 4 meters. Near vision was assessed using N notation chart. Uncorrected refractive error was defined as presenting visual acuity worse than 6/12 but improving to at least 6/12 or better on using a pinhole. Presbyopia is defined as binocular near vision worse than N8 in subjects aged more than 35 years with binocular distance visual acuity of 6/12 or better. Of the 3,300 subjects enumerated from 55 clusters, 3,203 (97%) subjects were available for examination. Of these, 1,496 (46.7%) were females and 930 (29%) were > or = 40 years. Age and gender adjusted prevalence of uncorrected refractive errors causing visual impairment in the better eye was 2.7% (95% CI, 2.1-3.2%). Presbyopia was present in 690 (63.7%, 95% CI, 60.8-66.6%) subjects aged over 35 years. Spectacle coverage for refractive error was 29% and for presbyopia it was 19%. There is a large unmet need for refractive correction in this area in India. Rapid assessment methods are an effective means of assessing the need for services and the impact of models of care.

Construction and validation of a Tamil logMAR chart

To design, construct and validate a new Tamil logMAR visual acuity chart based on current recommendations. Ten Tamil letters of equal legibility were identified experimentally and were used in the chart. Two charts, one internally illuminated and one externally illuminated, were constructed for testing at 4 m distance. The repeatability of the two charts was tested. For validation, the two charts were compared with a standard English logMAR chart (ETDRS). When compared to the ETDRS chart, a difference of 0.06 +/- 0.07 and 0.07 +/- 0.07 logMAR was found for the internally and externally illuminated charts respectively. Limits of agreement between the internally illuminated Tamil logMAR chart and ETDRS chart were found to be (-0.08, 0.19), and (-0.07, 0.20) for the externally illuminated chart. The test - retest results showed a difference of 0.02 +/- 0.04 and 0.02 +/- 0.06 logMAR for the internally and externally illuminated charts respectively. Limits of agreement for repeated measurements for the internally illuminated Tamil logMAR chart were found to be (-0.06, 0.10), and (-0.10, 0.14) for the externally illuminated chart. The newly constructed Tamil logMAR charts have good repeatability. The difference in visual acuity scores between the newly constructed Tamil logMAR chart and the standard English logMAR chart was within acceptable limits. This new chart can be used for measuring visual acuity in the literate Tamil population.

Survey Effect on Use of Eye Care by Older Persons with Correctable Visual Impairment

ABSTRACTPurpose: To assess changes in the pattern of eye care utilization among older Australians with correctable visual impairment, identified in an eye survey. Methods: The Blue Mountains Eye Study (BMES) examined 3654 Australians aged ≥ 49 years at baseline (BMES-I). Five-year follow-up examinations were attended by 2334 participants, 75.0% of survivors (BMES-II). Interviewers collected data on eye care utilization at each visit. Habitual (presenting) and best-corrected visual acuity were assessed using a LogMAR chart. Survey reports, including visual acuity and recommendations were sent to participants after each visit. Those with under-corrected refractive error were informed that they could benefit from a new distance prescription. Eye care utilization was compared before and after the BMES-I survey. Results: Of 2152 participants with data from both examinations, 26 had non-correctable and 115 had correctable visual impairment at BMES-I. The proportion of the 115 participants with correctable visual impairment who reported seeing an eye care provider during the previous 2 years increased from 55% at BMES-I to 64% at BMES-II. Comparing the data collected at BMES-II with that at BMES-I, a higher proportion of reported optometric visits in the previous 5 years was evident for all participants regardless of their correctable visual impairment status. Among those with correctable visual impairment at BMES-I, 58% improved to no visual impairment at BMES-II, and the proportion who subsequently wore distance correction increased from 57% to 71%. Conclusions: We observed modest increases in eye care utilization by older persons after an eye survey, particularly those with correctable visual impairment.

Comparison of the ETDRS logMAR, ‘compact reduced logMar’ and Snellen charts in routine clinical practice

To compare the performance of the ETDRS logMAR, compact reduced logMAR and Snellen charts in an ophthalmic outpatient setting. The reliability and reading times of the charts were compared in a stratified sample of 40 eyes of 40 ophthalmic patients with a variety of stable eye diseases. In order to simulate a clinical setting, forced-choice testing was not used. Similar acuity results were recorded from all three charts, suggesting a lack of a systematic bias as regards chart design. A small practice effect was observed for all charts but was greatest for Snellen and least for ETDRS. The test-retest variability of the charts was similar, with the 95% tolerance limit for change being +/-0.14 logMAR for ETDRS, +/-0.16 for reduced logMAR and +/-0.18 for Snellen. The mean reading times for the subjects were 34.65 s for ETDRS, 21.17 s for reduced logMAR and 18.67 s for Snellen. The performance of the compact reduced logMAR chart was intermediate between Snellen and ETDRS. The theoretical advantages of the ETDRS design were still measurable in a clinical setting but the magnitude of the advantage in terms of test-retest reliability was fairly small and the time taken to complete the EDTRS was 1.86 times that of the Snellen chart.

Characteristics of idiopathic epiretinal membrane by new Fourier-domain optical coherence tomography

Objective To observe the Fourier-domain optical coherence tomography(FD-OCT) characteristic of idiopathic epiretinal membrane (ERM) and its correlation with the visual acuity. Methods The 116 eyes (112 patients) with idiopathic epiretinal membrane were included in this study. All the had undergone examination of visual acuity (LogMAR chart), ocular fundus (direct ophthalmoscope and fundus pre-set lens), and FD-OCT (Zeiss HD-OCT) with the speed of 27 000 A scan/s, area of 6.0 mm× 6.0 mm, and mode of 512 × 128. The central fovea thickness (CFT), volume (V), average thickness (AT) were collected from the OCT readings, and the fovea thickness (FT) was measured manually. Data were analyzed using SPSS 16.0. Results The traction on retina caused by ERM can be divided into 3 types according to the OCT findings., no traction (9.48 %), tangential traction (84.48 %) and tangential traction with anterior-posterior traction (6.04 %). A total of 97 eyes (83.62 %) had retinal edema (diffuse or cystoid) and the edema located at the outer nuclear layer(ONL), outer plexiform layer(OPL)and inner nuclear layer (INL). A total of 14 eyes (12. 07%) had retinal nerve fiber layer (RNFL) schisis and 27 eyes (23.28%) had inner segment/outer segment j unction(Ls/OS) impairment. Statistic analysis revealed that BCVA was not related to the age, gender, types of traction, presence of IS/OS damage or RNFL schisis(P>0.05), but was related with CFT(P<0.05). Conclusions Idiopathic ERM can exert different types of traction on the macular, and cause different types of retinal lesions. OCT is a useful tool to measure these lesions. CFT reading is closely related to patients visual acuity. Key words: Macula lutea; Membranes; Tomography, optical coherence; Diagnostic imaging

Association Between the Nursing Home Minimum Data Set for Vision and Vision-Targeted Health-Related Quality of Life in Nursing Home Residents as Assessed by Certified Nursing Assistants

Purpose The purpose of this study was to evaluate the association between the federally mandated Minimum Data Set (MDS) Vision Patterns assessment for nursing home residents in the United States and an assessment of their vision-targeted quality of life as assessed by certified nursing assistants (CNAs). Methods Participants were 371 residents over the age of 55 from 17 nursing homes in the Birmingham, Alabama metropolitan area and the CNAs directly assigned to their care. CNAs assessed the vision-targeted quality of life of residents in their charge using the Nursing Home Vision-Targeted Health-Related Quality of Life (NHVQoL) questionnaire. MDS assessment categories assigned to each resident by the MDS nurse coordinator (“adequate”, “impaired”, “moderately impaired”, “highly impaired”, “severely impaired”) were obtained from the medical record. Visual acuity was measured using logMAR charts by trained research staff. Results CNA-rated NHVQoL subscale scores decreased as the MDS rating indicated more vision impairment (all P's for trend <0.05). Almost all mean scores were in the 80s and 90s for those in the adequate, impaired, and moderately impaired categories. For those with MDS ratings of severely or highly impaired, NHVQoL subscale scores (except ocular symptoms) were dramatically lower ( P≤0.001) than those rated as moderately impaired. Conclusions Ratings by CNAs on the vision-targeted quality of life of nursing home residents under their care is in general agreement with the MDS category assigned by the nurse coordinator. However, CNA ratings are largely homogeneous in the adequate vision to moderately impaired categories.

Uncorrected Refractive Errors, Presbyopia and Spectacle Coverage: Results from a Rapid Assessment of Refractive Error Survey

Purpose: To investigate the prevalence of uncorrected refractive errors, presbyopia and spectacle coverage in subjects aged 15–50 years using rapid assessment methodology in the Mahabubnagar district of Andhra Pradesh, India. Methods: A population-based cross sectional study was conducted using cluster random sampling to enumerate 3,300 subjects from 55 clusters. Unaided, aided and pinhole visual acuity was assessed using a LogMAR chart at a distance of 4 meters. Near vision was assessed using N notation chart. Uncorrected refractive error was defined as presenting visual acuity worse than 6/12 but improving to at least 6/12 or better on using a pinhole. Presbyopia is defined as binocular near vision worse than N8 in subjects aged more than 35 years with binocular distance visual acuity of 6/12 or better. Results: Of the 3,300 subjects enumerated from 55 clusters, 3,203 (97%) subjects were available for examination. Of these, 1,496 (46.7%) were females and 930 (29%) were ≥ 40 years. Age and gender adjusted prevalence of uncorrected refractive errors causing visual impairment in the better eye was 2.7% (95% CI, 2.1–3.2%). Presbyopia was present in 690 (63.7%, 95% CI, 60.8–66.6%) subjects aged over 35 years. Spectacle coverage for refractive error was 29% and for presbyopia it was 19%. Conclusions: There is a large unmet need for refractive correction in this area in India. Rapid assessment methods are an effective means of assessing the need for services and the impact of models of care.

Habitual vs optimal distance visual acuity

The maintenance of a good level of vision is desirable for developmental and social reasons; it is also a requirement that should not be overlooked in the clinical research environment. This study set out to quantify and analyse any difference between 'habitual' (pre-sight test) and 'optimal' (post-refraction) distance visual acuity in an optometric population. It is intended that the outcome of this work will inform not only clinicians but also those undertaking vision research. Binocular logMAR visual acuity was determined at 6 m before and after optometric intervention in patients attending optometric practice for a routine sight test. Cases were recorded seriatim but restricted to the 'core' refraction range representative of typical optometric practice; three further exemption criteria included subject illiteracy, the necessity for a non-standard test distance and contact lens wear. Over a 12-month period, two-thirds of patients examined satisfied the study inclusion criteria; it is the clinical data of these 1288 individuals that are described and analysed here. These data provide a quantitative demonstration that an optometric intervention will most likely improve the habitual distance visual acuity of subjects, irrespective of gender, age group, time interval since last test, refractive status and whether or not the subject is a habitual spectacle wearer. The improvement found was typically within one logMAR chart line (<5 letters), being greatest in spectacle-wearing teenagers and in individuals beyond retirement age (increasing to eight letters in elderly habitual non-spectacle wearers); also in non-wearers who left an interval of 2 years or more between sight tests. Clinical and laboratory-based investigators are advised that a current and optimal refractive correction should be worn by subjects of all ages enrolled in vision-related studies. Refractive defocus may introduce or exaggerate test outcome variability.

Associations between Anisometropia, Amblyopia, and Reduced Stereoacuity in a School-Aged Population with a High Prevalence of Astigmatism

To describe the relation between magnitude of anisometropia and interocular acuity difference (IAD), stereoacuity (SA), and the presence of amblyopia in school-aged members of a Native American tribe with a high prevalence of astigmatism. Refractive error (cycloplegic autorefraction confirmed by retinoscopy), best corrected monocular visual acuity (VA; Early Treatment Diabetic Retinopathy Study logMAR charts), and best corrected SA (Randot Preschool Stereoacuity Test) were measured in 4- to 13-year-old Tohono O'odham children (N = 972). Anisometropia was calculated in clinical notation (spherical equivalent and cylinder) and in two forms of vector notation that take into account interocular differences in both axis and cylinder magnitude. Astigmatism >or= 1.00 D was present in one or both eyes of 415 children (42.7%). Significant increases in IAD and presence of amblyopia (IAD >or= 2 logMAR lines) occurred, with >or=1 D of hyperopic anisometropia and >or=2 to 3 D of cylinder anisometropia. Significant decreases in SA occurred with >or=0.5 D of hyperopic, myopic, or cylinder anisometropia. Results for vector notation depended on the analysis used, but also showed disruption of SA at lower values of anisometropia than were associated with increases in IAD and presence of amblyopia. Best corrected IAD and presence of amblyopia are related to amount and type of refractive error difference (hyperopic, myopic, or cylindrical) between eyes. Disruption of best corrected random dot SA occurs with smaller interocular differences than those producing an increase in IAD, suggesting that the development of SA is particularly dependent on similarity of the refractive error between eyes.

Visual prognosis and vitreous cytokine levels after arteriovenous sheathotomy in branch retinal vein occlusion associated with macular oedema

To investigate the relationship between vitreous levels of cytokines, including interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF), and visual prognosis after pars plana vitrectomy (PPV) with arteriovenous sheathotomy in patients with branch retinal vein occlusion (BRVO) associated with macular oedema. We studied 60 patients with logMAR visual acuity (VA) scores of < 0.3 and visual impairment secondary to BRVO-associated macular oedema. All patients underwent PPV with arteriovenous sheathotomy. At the time of PPV, vitreous samples were collected from the operated eye and vitreous levels of VEGF and IL-6 were measured. Best corrected VA (BCVA) (using a logMAR chart) and foveal thickness (FT) (using optical coherence tomography) were monitored for up to 6 months after PPV. Both BCVA and FT significantly improved after PPV. According to multiple regression analysis, both the improvement in BCVA and decrease in FT were closely related to the vitreous level of IL-6 but not to that of VEGF. The vitreous level of VEGF was strongly correlated with duration of BRVO. Both improvement in BCVA and decrease in FT were observed after PPV in BRVO patients with macular oedema. Interestingly, these visual prognoses strongly correlate with the vitreous level of IL-6, whereas the duration of BRVO strongly correlates with the vitreous level of VEGF.

Prevalence and causes of blindness and Low Vision in Ethiopia

Background: Ethiopia lacked accurate recent national estimates of blindness and low vision. Therefore, prevention and control programs face serious problem of lack of recognition of the problem and challenges in tracking achievements towards program goals. Objective: To determine the prevalence of blindness and low vision at the national and regional levels in Ethiopia. Method: A national survey was conducted on a representative population in all nine regional states and two city administrations of the country. The LogMar chart was used to determine the presenting visual acuity and ophthalmologists determined the primary cause of low vision and blindness. Results: Based on the assessment of the presenting visual acuity, the national prevalence of blindness is 1.6% (1.1% for urban and 1.6% for rural populations) and that of low vision is 3.7% (2.6% for urban and 3.8% for rural populations). Blindness and Low vision are more prevalent among females. The major causes of blindness are cataract and trachomatous corneal opacity. The major causes of low vision are cataract and refractive error. Prevalence of childhood blindness is 0.1% and accounts for over 6% of the total blindness burden in Ethiopia. The national prevalence of Bitot\'s spots is 0.7%. Conclusion: Blindness and low vision are major public health problems in Ethiopia. The large proportion of low vision (91.2%) and blindness (87.4%) are due to avoidable (either preventable or treatable) causes. Females and rural residents carry greater risk for eye problems. Adequate emphasis needs to be given to prevent blindness among children and avert millions of years of unnecessary blindness. Recognizing the severity of the magnitude of eye problems (blindness and low vision) and enhancing the government commitment to improve the situation is critical.Ethiopian Journal of Health Development Vol. 21 (3) 2007: pp. 204-210

National Survey on Blindness, Low Vision and Trachoma in Ethiopia: Methods and Study Clusters Profile

Background: The magnitude and causes of eye diseases in Ethiopia has been derived from small scale studies. This information became no longer useful in tracking the success of intensified efforts in preventing and controlling avoidable causes of blindness and eye diseases in line with the goals of Vision 2020: The Right to Sight. Objective: The national household survey was conducted primarily to provide national and regional state level estimates of low vision, blindness and trachoma. The secondary aims include describing the major causes of low vision and blindness. Methods: The national survey utilized cross sectional epidemiological study design with multistage sampling strategy. All nine regional states and two city administrations of the country were involved in the survey. Sample size and sampling strategies were developed taking into account population size of the regional states. Visual acuity was tested using the LogMar chart and trachoma grading was done following the WHO grading system. The cause of low vision and blindness were determined by ophthalmologists. Results: A total of 174 clusters, 6056 households and 30022 individuals were involved in the survey. Of the total 30022 individuals 25650 (85.4%) were present and examined by the survey team. Implementing quality control supervision in the very remote clusters was a major challenge. About 55% of the survey clusters were within 10 Km of health facility that stock tetracycline; 18.3% within 10 Km of health facility that provides Trachomatous Trichiasis (TT) surgery and 18.6% were within 10Km of health facility that provides cataract surgery. Only 29.4% of the survey clusters were fully accessible by car. The majority of survey household head were farmers (70.8%) and illiterate (64.5%). About 48% of the households obtain their water from either a protected well/spring or piped distribution. Only 40.4% of the households reported that no animal is kept around the living quarter. Most households dispose garbage in open field (84.6%) and have no latrine (60.3%). Conclusion: The survey was conducted on a representative sample and provides reliable estimates at the national and regional levels. However, careful interpretations of results from remote and inaccessible areas are warranted. Access to eye care facilities are limited and need expansion in order to reduce the blindness and low vision load. Sanitation conditions favoring fly breeding are rampant and trachoma control program need to emphasize a more integrated approach.Ethiopian Journal of Health Development Vol. 21 (3) 2007: pp. 185-203