Reliability of Aberrometry Versus Cycloplegic Retinoscopy in Prescribing Glasses to Undilated Child

S.A. Erzurum, MD FACSAylin Sarac

Financial Interest

The authors have no financial interests in any of the topics discussed in this study.

Purpose of Study

Retinoscopy is a difficult skill for many eye care professionals.

Children are a difficult subpopulation for eye care professional to refract.

Inaccurate glass prescribing occurs for many children.

Dilation necessary for accurate refraction but disliked by children and family.

Purpose of Study

Find a reliable method for non-specialized eye care providers to prescribe glasses for children.

Reliable method should be easy and quick.

Find method that eliminates/reduces need for dilating drops to check refraction.

Method

iZON Aberrometer was machine used for comparison to cycloplegic refraction.

Images are taken before dilation.

Child sits upon parent’s lap and multiple rapid images are obtained.

Immediately upon taking image, analysis is provided of sphere, cylinder, axis, level of aberrations, and quality of image.

Example of reliable image capture.

Prescription measured and reported as sphere, cylinder, and axis.

Aberrations measured and reported in green, yellow or red.

Pictures demonstrate how patient sees at night.

Example of poor image and unreliable readings.

No measurements are provided for aberrations.

Whatever prescription was captured is reported, but may not be reliable.

Example of right eye with poor image capture and left eye with excellent capture.

Right eye results for refraction may not be reliable.

Left eye results reliable.

Method

Prospective consecutive series of 256 eyes in 128 pediatric patients involved in full exam.

Age range of 3 to 18 years.

iZON aberrometer images prior to dilation.

Full eye exam with cycloplegic refraction.

No patients were excluded, and all were examined by the same pediatric ophthalmologist.

Results

CYCLOPLEGIC ABERROMETER (mean +/- SD) (mean +/- SD)

Sphere 0.42 + 2.95 -0.05 + 2.16 Astigmatism 0.74 + 0.91 0.92 + 1.52 Spheric equiv 0.75 + 2.91 0.39 + 2.17

Age (mean + SD) 8.1 + 3.2 years; Mode 7 years Range 3-18 years

Female 62 48.4% Male 66 51.6%

Prevalence of Eye Disorders in Study Patients

Prevalence of Eye Disorders– Normal 120 46.9– Esotropia 32 11.3– Amblyopia 29 12.5– Exotropia 9 3.5– Cerebral palsy/ 7 2.7 developmental delay– Congenital nystagmus 4 1.6– Cataracts 3 1.2– IDDM 4 1.6– Duane’s 3 1.2– Best’s 1 0.4– Coloboma 1 0.4

Reliability of Aberrometer

Only 45 eyes of 256 (17%)had an unreliable reading and were excluded from comparison.

26 eyes of these 45 (64%)had ocular pathology which would have directed them to sub-specialized care.

Immediately upon taking image, examiner is aware of reliability of image.

Results of Comparison between two Methods

Comparison between aberrometer and cycloplegic results were made in each area of sphere, cylinder, and axis.

In all categories, correlation was high between the two methods.

Offset and slope of the best fit regression were calculated for each.

All comparisons showed the slope was very close to 1.

Y cyclo sphere = 1.04 X izon sphere + 0.469

Model ANOVA F = 1552.93, p < 0.001

R = 0.934

Y cyclo SPHEQ = 1.019 X izon SPHEQ + 0.400

Model ANOVA F = 718.782 p < 0.001

R = 0.865

Y cyclo astig = 0.909 X izon astig – 0.026

Model ANOVA F = 766.735 p < 0.001

R = 0.887

Sphere Spherical Equivalent

Astigmatism

Conclusions

iZON aberrometer is a reliable method of refraction to assist practitioners uncomfortable with cycloplegic refraction in children.

iZON aberrometer gives a reliable reading and a high correlation with cycloplegic refraction.

Group of patients who showed higher unreliability by aberrometry measurements had a higher chance of ocular pathology.