Abstract
PurposeTo evaluate intra- and intersession repeatability of objective optical quality and intraocular scattering measurements with a double-pass system in children.MethodsForty-two eyes of 42 children were included in the study. An optical quality analysis system (OQAS) was used to measure optical quality parameters, including modulation transfer function cutoff frequency (MTFcutoff), Strehl ratio (SR), OQAS values (OV) at 3 different contrasts and objective scatter index (OSI). Three measurement sessions with 10-min intervals were operated by the same technician, and in each session four consecutive measurements were obtained.ResultsMean values for MTFcutoff, SR and OSI were 46.85 ± 7.45cpd, 0.27 ± 0.06 and 0.34 ± 0.22 respectively. 1) The intraclass correlation coefficients were ranged from 0.89 to 0.97 and coefficients of variation from 0.06 to 0.16 for all the parameters in the first session; the relative repeatability were 11.1% (MTFcutoff), 22.5% (SR), 10.9% (OV100%), 16.6% (OV2%), 22.4% (OV9%) and 56.3% (OSI). Similar results were found in the second and third sessions. 2) Bland-Altman analysis showed that narrow 95% confidence intervals (compared between the first and second sessions) ranged from -5.42 to 5.28 (MTFcutoff), -0.05 to 0.07 (SR), -0.18 to 0.18 (OV100%), -0.26 to 0.29 (OV20%), -0.33 to 0.39 (OV9%) and -0.11 to 0.09 (OSI); the comparison between any two of the three sessions showed similar results.ConclusionMeasurements of optical quality and intraocular scattering in children by the double-pass system showed good intra- and intersession repeatability. Retinal image quality is high and intraocular scattering is low in children.
Highlights
The most commonly used method for objective optical quality assessment is wavefront aberration measuring
Retinal image quality is high and intraocular scattering is low in children
The optical quality analysis system (OQAS)[1,2] directly computes the modulation transfer function (MTF) from the acquired double-pass retinal image through Fourier transformation; low-order aberrations are corrected in advance and the acquired retinal image contains both the information about high-order aberrations and intraocular scattering.[3]
Summary
The most commonly used method for objective optical quality assessment is wavefront aberration measuring. A newly developed system based on the double-pass technique has come into clinical use. The optical quality analysis system (OQAS)[1,2] directly computes the modulation transfer function (MTF) from the acquired double-pass retinal image through Fourier transformation; low-order aberrations are corrected in advance and the acquired retinal image contains both the information about high-order aberrations and intraocular scattering.[3] Previous studies have demonstrated that the double-pass system has good repeatability for optical quality measurements in adults.[4,5,6] The system provides parameters that derive from the MTF curve for retinal image quality assessment and objective scatter index for intraocular scattering evaluation. Normal value reference database of these parameters obtained from the double-pass system, which is available for clinical analysis, was collected using the data from a population of healthy young adults.[7]
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