Agreement and relationship between ultrasonic and partial coherence interferometry measurements of axial length and anterior chamber depth

Abstract

Purpose

To find the relationship between axial length (AL) and anterior chamber depth (ACD) measurements, using partial coherence interferometry (PCI) and A-scan ultrasonography (US).

Setting

National Eye Hospital, Cairo, Egypt.

Method

Retrieving and comparing biometric data from the files of 163 consecutive patients seeking cataract extraction by PCI (IOLMaster) and US (Sonomed).

Results

AL measured using US range from 20.93 to 33.17 mm (mean ± SD = 24.45 ± 2.73 mm). AL measured by PCI range from 20.90 to 33.27 mm (24.05 ± 2.76 mm). The range of ACD measured by US was 2.09 to 4.48 mm (3.32 ± 0.46 mm). The range of ACD measured by PCI was 2.15 to 4.29 mm (3.31 ± 0.45 mm). There is very high agreement between both methods; the intraclass correlation coefficient = 0.999 for AL, and 0.966 for ACD measurements. A linear regression model of two formulae fits the AL values (one for eyes longer than 29 mm, and the other for the shorter eyes), with no significant departure from linearity (P > 0.1). One formula fits the ACD values with significant departure from linearity (P < 0.05).

Conclusion

Both US and PCI methods for measurements of AL and ACD are highly correlated. Therefore, the value of AL measured by one method can be predicted, with high accuracy, from the other method.

Keywords:

• axial length
• anterior chamber depth
• A-scan US
• partial coherence interferometry

Disclosure

The authors did not receive any financial support from any public or private sources. The authors have no financial or proprietary interests in a product, method, or material described herein.