Reliability and validity of the partial coherence interferometry for measurement of ocular axial length in children

Abstract

Purpose To assess the validity and repeatability of partial coherence interferometry (IOLMaster) and A-scan ultrasound measurement of axial length (AL) in children. Methods A prospective comparison of AL measurement made by the IOLMaster optical instrument (Carl Zeiss) and ultrasound A-scan (Alcon) was performed. A total of 20 children (11 male, nine female) were recruited into the study; the mean age of the sample was 11.4 years (range 6.2-15.8). Inclusion criteria comprised individuals o16 years, with no ocular pathology and no previous eye operations or allergy to topical anaesthetics. All measurements were performed by a single examiner. Results Data on validity show that, on average, a small measurement difference existed between these groups with the IOLMaster being 0.017 mm greater than A-scan ultrasonography. The 95% confidence interval for this difference encompasses zero, demonstrating that no significant systematic bias exists between the two-measurement techniques. Overall, IOLMaster reliability exceeded that of A-scan. This is evidenced primarily by the spread of the paired test-retest difference for A-scan compared to IOLMaster. The mean test-retest difference for A-scan was considerably larger than IOLMaster at 0.042 and 0.004 mm, respectively. Conclusion The results show that IOLMaster was more accurate and reproducible than the contact ultrasonographic technique when used in children. Such results indicate that IOLMaster may be a useful tool in studies of eye growth and refractive development in children.

Axial Length Measurement Using Partial Coherence Interferometry in Myopic Children: Repeatability of the Measurement and Comparison with Refractive Components

“…21 Hussin et al 17 and Carkeet et al 18 performed 3 and 12 consecutive scans, respectively, with IOLMaster in children and observed no side effects, including photoretinopathy. Accordingly, we did not perform the measurement more than six times (three times for the fi rst and three times for the second measurement) per day, on principle, to allow a safety margin.…”

“…16,26 In children, the reported repeatability differs widely among researchers (±0.23-0.85 mm), 17,18 presumably because the repeatability is dependent on how much cooperation was obtained from the children. Compared with these values, the repeatability of the IOLMaster measurement that we found in children was 5 to19 times more precise.…”

“…Another advantage of this device is its high precision. 15,16 In children, Carkeet et al 17 and Hussin et al 18 reported that test-retest repeatability of this measurement was ±0.047 mm and ±0.04 mm, respectively (Table 1). However, these studies provided no information regarding refractive errors in the subjects, and thus it is still unknown whether the reported repeatability can be expected in children with a wide range of refractive errors.…”

Anisometropic amblyopia: Axial length versus corneal curvature in children with severe refractive imbalance

“…Its advantages include its ability to capture reliable measurements of axial length, corneal curvature, anterior chamber depth, and corneal diameter and its noninvasive, rapid execution, even in young children. 6,7 This may help explain how it was possible to recruit and to complete testing of all parameters on 13 of 14 children aged 7-8 identified as candidates for the study.…”

Testability of the Retinomax Autorefractor and IOLMaster in Preschool Children

“…Partial coherence interferometry has not been previously studied in preschoolers, but it has been demonstrated to be more reproducible than A-scan ultrasonography in measuring axial length in school age children. 9,10 Ophthalmologists and optometrists with pediatric subspecialty training performed all of the tests in this study. Testability of preschoolers with these devices using non-professionals in a screening setting may thus be less.…”