Amblyopia: a comparison between distance and near vision

Is there value in measuring near visual acuity during occlusion therapy for amblyopia?

Introduction: The purpose of this study was to investigate near and distance visual acuity (VA) prior to, during and on completion of occlusion therapy for amblyopia. Method: Fifty-four patients aged 4-7 years (mean 4.9; ±0.44) with untreated strabismic, anisometropic or mixed amblyopia were recruited to the study following refractive adaptation where applicable. All patients underwent conventional occlusion (patching). Uniocular near and distance VA was tested using age and ability appropriate Crowded LogMAR VA tests prior to, during and upon conclusion of occlusion therapy. Results: In amblyopic eyes, there was no significant difference between near and distance VA prior to occlusion therapy with LogMAR Crowded (p = .66; mean distance VA at 3 m = 0.6 LogMAR; mean near VA at 40 cm = 0.58 LogMAR), or with LogMAR Crowded Kay Picture test (p = .78, mean distance VA at 3 m = 0.44 LogMAR; mean near VA at 33 cm = 0.46 LogMAR;). No significant difference was found between near and distance VA at any visit during occlusion therapy, or on completion of occlusion therapy with LogMAR Crowded (p = .86, mean final distance VA at 3 m = 0.266 LogMAR; mean final near VA at 40 cm = 0.25 LogMAR) or LogMAR Crowded Kay Pictures (p = .74, mean final distance VA at 3 m = 0.16 LogMAR; mean final near VA at 33 cm = 0.16 LogMAR). There was no significant difference in the VA of the fellow (non-amblyopic) eyes prior to and on completion of occlusion therapy with LogMAR Crowded at distance (3 m) or near (40 cm) (p = .05, p = .40 respectively); or with LogMAR Crowded Kay Pictures at distance (3 m) or near (33 cm) (p = .89, p = .35 respectively). Discussion: Improvement in VA of amblyopic eyes did not significantly differ between near and distance testing proximites at any point during the course of occlusion therapy for amblyopia in our study. These findings may aid clinicians with appropriate test selection and help with clinical time pressures. Where patient concentration does not allow for uniocular distance vision, uniocular near vision may be used to diagnose amblyopia, and vice versa. This could prevent delay in the treatment of amblyopia.

Comparison of Visual Acuity Measurement Using Three Methods: Standard ETDRS Chart, Near Chart and a Smartphone-Based Eye Chart Application

Purpose

To validate the Rosenbaum near vision card (Near Chart) and a smartphone-based visual acuity (VA) test (Eye Chart) against a standard retro-illuminated Early Treatment Diabetic Retinopathy Study (ETDRS) chart within participants.

Materials and Methods

A cross-sectional study of participants aged ≥18 years was conducted. VA was measured in all participants using the ETDRS chart, Near Chart and smartphone-based Eye Chart application, respectively. VA was converted to logarithm of the minimum angle of resolution (logMAR) for statistical analysis. Eyes with ETDRS VA worse than 1.0 logMAR (20/200) were excluded. The main outcome measures were levels of agreement between VA measured using the Near Chart or Eye Chart application vs the ETDRS chart.

Results

A total of 295 eyes of 151 participants were included. One hundred participants (66.2%) were female and the mean age was 64.3 ± 12.5 years. Educational level was high school or below for 49% of participants and at Bachelor's degree or above for 51%. The median logMAR VAs of all eyes tested using the ETDRS chart, Near Chart and Eye Chart application were 0.1, 0.0 and 0.1, respectively. The median VA difference between the Near Chart vs ETDRS chart and Eye Chart application vs ETDRS chart was 0.0 logMAR in both cases for both the right eye (OD) and left eye (OS). Intraclass correlation coefficient (ICC) demonstrated a strong positive correlation between VA tested with the Near Chart vs ETDRS chart (OD: ICC=0.85; p<0.001, OS: ICC=0.77; p<0.001) and Eye Chart application vs ETDRS chart (OD: ICC=0.88; p<0.001, OS: ICC=0.74; p<0.001).

Conclusion

VA measurements with the Near Chart and smartphone-based Eye Chart application corresponded well to the standard ETDRS chart, suggesting potential utility of alternative portable VA tests for in-office or remote vision monitoring, particularly during periods of physical distancing such as the Coronavirus disease 2019 (COVID-19) era.

Comparison between distance and near visual acuity in amblyopes

To compare distant visual acuity (DVA) and near visual acuity (NVA) in amblyopia and evaluate if NVA can be used to diagnose amblyopia.A retrospective study was performed on 73 patients diagnosed with amblyopia based on DVA, by measuring their NVA and comparing the DVA and NVA. The NVA was measured by Snellen chart at 30 cm and the DVA was measured by Dr Hahn vision test chart at 5m. The patients' age, type of amblyopia, spherical equivalent, the difference between spherical equivalent and the fellow eye spherical equivalent spherical, and prism diopter (PD) were evaluated and their relationship with the difference between the DVA and NVA was analyzed.The NVA was significantly better than the DVA in amblyopia (P = .000). The difference between the DVA and NVA was not significantly related to the type of amblyopia (P = .600) or the patients' age(P = .351). Also, the difference between the DVA and NVA was not significantly affected by the spherical equivalent (P = .425) or the difference between spherical equivalent and the fellow eye spherical equivalent (P = .212) in anisometropia amblyopia, and also not by the PD (P = .882) in strabismus amblyopia.In amblyopes, the NVA was better than the DVA before amblyopia treatment. The difference between the DVA and NVA was not affected by age, type of amblyopia, spherical equivalent, the difference between spherical equivalent and the fellow eye spherical equivalent spherical, or PD. Therefore, it should be taken into consideration that NVA could underestimate the severity of amblyopia and affect the accuracy at diagnosing amblyopia.

Automated Measurement of Visual Acuity in Pediatric Ophthalmic Patients Using Principles of Game Design and Tablet Computers

PURPOSE

To report on the utility of a computer tablet-based method for automated testing of visual acuity in children based on the principles of game design. We describe the testing procedure and present repeatability as well as agreement of the score with accepted visual acuity measures.

DESIGN

Reliability and validity study.

METHODS

Setting: Manchester Royal Eye Hospital Pediatric Ophthalmology Outpatients Department.

PATIENT POPULATION

Total of 112 sequentially recruited patients.

INTERVENTION

For each patient 1 eye was tested with the Mobile Assessment of Vision by intERactIve Computer for Children (MAVERIC-C) system, consisting of a software application running on a computer tablet, housed in a bespoke viewing chamber. The application elicited touch screen responses using a game design to encourage compliance and automatically acquire visual acuity scores of participating patients. Acuity was then assessed by an examiner with a standard chart-based near ETDRS acuity test before the MAVERIC-C assessment was repeated.

MAIN OUTCOME MEASURE

Reliability of MAVERIC-C near visual acuity score and agreement of MAVERIC-C score with near ETDRS chart for visual acuity.

RESULTS

Altogether, 106 children (95%) completed the MAVERIC-C system without assistance. The vision scores demonstrated satisfactory reliability, with test-retest VA scores having a mean difference of 0.001 (SD ±0.136) and limits of agreement of 2 SD (LOA) of ±0.267. Comparison with the near EDTRS chart showed agreement with a mean difference of -0.0879 (±0.106) with LOA of ±0.208.

CONCLUSIONS

This study demonstrates promising utility for software using a game design to enable automated testing of acuity in children with ophthalmic disease in an objective and accurate manner.

Distance versus near visual acuity in amblyopia

PURPOSE

There are conflicting reports about whether distance and near visual acuity are similar in eyes with amblyopia. The purpose of this study is to compare monocular distance visual acuity with near visual acuity in amblyopic eyes of children.

METHODS

Subjects 2 to 6 years of age were evaluated in a randomized trial of amblyopia therapy for moderate amblyopia (20/40 to 20/80) due to anisometropia, strabismus, or both. Prior to initiating the protocol-prescribed therapy, subjects had best-corrected visual acuity measured with standardized protocols at 3 meters and 0.4 meters using single-surrounded HOTV optotypes.

RESULTS

A total of 129 subjects were included. The mean amblyopic eye visual acuity was similar at distance and near (mean, 0.45 logMAR at distance versus 0.45 logMAR at near; mean difference, +0.00, 95% CI, -0.03 to 0.03). Of the 129 subjects, 86 (67%) tested within 1 line at distance and near; 19 (15%) tested more than 1 logMAR line better at distance, and 24 (19%) tested more than 1 logMAR line better at near. The mean visual acuity difference between distance and near did not differ by cause of amblyopia, age, or spherical equivalent refractive error.

CONCLUSIONS

We found no systematic difference between distance and near visual acuity in 2- to 6-year-old children with moderate amblyopia associated with strabismus and/or anisometropia. Individual differences between distance and near visual acuity are likely due to test-retest variability.

The R.A.F. near-point rule

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