Axial elongation measured by long scan depth optical coherence tomography during pilocarpine-induced accommodation in intraocular lens-implanted eyes

Yilei Shao,Jianhua Wang,Di Hu,Yimin Yuan,Dexi Zhu,Fan Lu,Meixiao Shen,Lin Leng,Lingmin Zhang,Qi Chen,Shenghai Huang,Qiuruo Jiang

doi:10.1038/s41598-018-19910-0

Yilei Shao, Jianhua Wang + Show 10 more

Open Access

https://doi.org/10.1038/s41598-018-19910-0

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Journal: Scientific Reports	Publication Date: Jan 31, 2018
Citations: 5	License type: open-access

Affiliation: Wenzhou Medical University, University of Miami

Abstract

We used an ultra-long scan depth optical coherence tomography (UL-OCT) system to investigate changes in axial biometry of pseudophakic eyes during pilocarpine- induced accommodation. The right eyes from 25 healthy subjects (age range 49 to 84 years) with an intraocular lens (IOL) were imaged twice in the non-accommodative and the accommodative states. A custom-built UL-OCT instrument imaged the whole eye. Then accommodation was induced by two drops of 0.5% pilocarpine hydrochloride separated by a 5-minute interval. Following the same protocol, images were acquired again 30 minutes after the first drop. The central corneal thickness (CCT), anterior chamber depth (ACD), IOL thickness (IOLT), and vitreous length (VL) were obtained using custom automated software. The axial length (AL) was calculated by summing the CCT, ACD, IOLT, and VL. With accommodation, ACD increased by +0.08 ± 0.09 mm, while the VL decreased by −0.04 ± 0.09 mm (paired t-test each, P<0.05). CCT and IOLT remained constant during accommodation (P > 0.05). The non-accommodative AL was 23.47 ± 0.93 mm, and it increased by +0.04 ± 0.04 mm after accommodation (P<0.01). The AL increased and the IOL moved backward during pilocarpine-induced accommodation in pseudophakic eyes.

Highlights

Accommodation in the human eye is a dynamic process that originates from the contraction of ciliary muscle and results in the reshaping of the crystalline lens
Considering that the ciliary muscle in aging human eyes still has the capability of contraction[25,26,27], we used UL–OCT to evaluate the change in ocular axial length (AL) during pilocarpine-induced accommodation in patients with implanted intraocular lens (IOL)
central corneal thickness (CCT) and intraocular lens thickness (IOLT) remained constant during accommodation (P > 0.05)

Summary

Introduction

Accommodation in the human eye is a dynamic process that originates from the contraction of ciliary muscle and results in the reshaping of the crystalline lens. With A-scan ultrasound, which requires contact of the probe on the corneal surface, the AL was reported to increase[3] or remain constant[13,14] during accommodation In these studies, the effect of placing the ultrasound probe on the cornea could have influenced the results. Changes in the shape of the crystalline lens during accommodation may result in changes of the effective refractive index This could lead to a change of optical path distance and subsequent deviation of the measurement from the true change in AL18–21. Because the exact change in refractive index of the crystalline lens during accommodation is not known, the values of AL during accommodation in those studies still may not be the true value at that time This cross-sectional and population-based study was performed using UL-OCT to investigate changes in axial biometry of pseudophakic eyes during pilocarpine-induced accommodation. Considering that the ciliary muscle in aging human eyes still has the capability of contraction[25,26,27], we used UL–OCT to evaluate the change in ocular AL during pilocarpine-induced accommodation in patients with implanted IOLs

Methods

Results

Conclusion