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Amplitude of accommodation measurements using the Donders clinical methods

Compartir 16/07/2015 Publicaciones Científicas

J. Pujol , R. Borrás, F.J. Paniagua, A. Sánchez-Magan, J. C. Ondategui-Parra

DAVALOR Research Center (DRC) Universitat Politècnica de Catalunya, Terrassa, Spain

Purpose

To compare the results of an automated system to measure the amplitude of accommodation with the subjective methods commonly used in clinics. The former one being implemented in a prototype of a new fully autonomous and automated vision analyzer (Eye and Vision Analyzer, EVA, DAVALOR, Spain) that records eye movements, pupil diameter values and refractive state while the patient watches a true-3D short video game.

Methods

Measurements were performed in a group of 54 young (mean±SD 21.9±1.6 years; range: 19 to 24) healthy subjects with no history of strabismus, amblyopia, ocular disease or previous eye surgery. Monocular visual acuity for far and near distance equal or better than 0.0 logMAR were required. Clinical methods consisted of Donders' push-up (CAAPU) when the patient detects blur vision while the optotype is coming near and Donders' push-down (CAAPD), when the patient detects clear vision while the optotype is moving away. Both methods were performed with a speed of 2 cm/sec and under controlled conditions of ilumination (L≈450 lux).The exams were performed in two sessions to determine the intra subjects variability and for two examiners, to determine the inter examiner variability.

EVA measurements were performed in a subsample of 24 subjects (mean±SD 22.6±2.0 years; range: 19 to 24) also looking for the blur point of vision with the method Donders’ push-up (EAAPU) and the point of clear vision with the Donders’s push-down (EAAPD) in a subsample of 24 subjects. Three measurements were done for each amplitude of accommodation methods.

Results

Mean values of amplitude of accommodation were 10.58±1.86D for CAAPU, 10.55±1.80Dfor CAAPD. The mean difference for both methods was 0.03±1.85D (p=0.91). The PearsonCorrelation was 0.5 (p>0.001). For the Bland Altman plot the Confidence Interval at 95%was between -3.6 to 3.6D. The intra-observer variability showed a difference of 0,5±2,2 D(p=0,11) and the inter-examiner repeatability was 1,2±2,2 D (p<0,001).

For EVA device the mean values were 9.83±1.90D for EAAPU and 9.03±1.89D for EAAPD.The mean difference for both methods was 0.80±0.21D (p<0.001). The Pearson Correlationwas 0.99 (p<0.001). For the Bland Altman plot the Confidence Interval at 95% was between0.38 to 1.22D. Comparing clinical and automated methods there were not statisticallysignificant differences for push-up method -0.39D (p=0.448) or push-down method -0.57D(p=0.267).

Conclusions

The EVA prototype is a useful device to measure amplitude of accommodation using both push-up and push-down procedures.Clinical procedures for measure the amplitude of accommodation show a good agreement between both methods. For EVA instrument the agreement between methods is higher than in clinical methods.

 

Amplitude of accommodation measurements using the Donders clinical methods and a new vision analyzer (PDF)

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Jaume Pujol
Director del DRC y Director del consejo clínico de Davalor

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