TY - JOUR
T1 - Ciliary Muscle Dimension Changes With Accommodation Vary in Myopia and Emmetropia
AU - Kaphle, Dinesh
AU - Schmid, Katrina L
AU - Davies, Leon N
AU - Suheimat, Marwan
AU - Atchison, David A
N1 - Funding Information:
Dinesh Kaphle was supported by a postgraduate Research Award from Queensland University of Technology.
Funding Information:
Supported by a grant from Carl Zeiss Vision. Deborah Laughton, Benjamin Coldrick, and Amy Sheppard contributed to the programming. The authors alone are responsible for the content and writing of the paper.
Publisher Copyright:
Copyright 2022 The Authors.
PY - 2022/6/1
Y1 - 2022/6/1
N2 - Purpose: The purpose of this study was to determine whether accommodation-induced changes in ciliary muscle dimensions vary between emmetropes and myopes, and the effect of the image analysis method.Methods: Seventy adults aged 18 to 27 years consisted of 25 people with emmetropia (spherical equivalent refraction [SER] +0.21 ± 0.36 diopters [D]) and 45 people with myopia (-2.84 ± 1.72 D). There were 23 people with low myopia (>-3 D) and 22 people with moderate myopia (-3 to -6 D). Right eye ciliary muscles were imaged (Visante OCT; Carl Zeiss Meditec) at 0 D and 6 D demands. Measures included ciliary muscle length (CML), ciliary muscle curved length (CMLarc), maximum ciliary muscle thickness (CMTmax), CMT1, CMT2, and CMT3 (fixed distances 1-3 mm from the scleral spur), CM25, CM50, and CM75 (proportional distances 25%-75%). Linear mixed model analysis determined effects of refractive groups, race, and demand on dimensions. Significance was set at P < 0.05.Results: Myopic eyes had greater CML and CMLarc nasally than emmetropic eyes. Myopic eyes had thicker muscles than emmetropic eyes at nasal positions, except CM25 and CMT3, and at CM75 temporally. During accommodation and only nasally, CML reduced in emmetropic and myopic eyes, and CMLarc reduced in myopic eyes only. During accommodation, both nasally and temporally, muscles thickened anteriorly (CMT1 and CM25) and thinned posteriorly (CMT3 and CM75) except for temporal CM75. Moderate myopic eyes had greater temporal CMLarc than low myopic eyes, and the moderate myopes had thicker muscles both nasally and temporally using fixed and proportional distances.Conclusions: People with myopia had longer and thicker ciliary muscles than people with emmetropia. During accommodation, the anterior muscle thickened and the curved nasal muscle length shortened, more in myopic than in emmetropic eyes. The fixed distance method is recommended for repeat measures in the same individual. The proportional distance method is recommended for comparisons between refractive groups.
AB - Purpose: The purpose of this study was to determine whether accommodation-induced changes in ciliary muscle dimensions vary between emmetropes and myopes, and the effect of the image analysis method.Methods: Seventy adults aged 18 to 27 years consisted of 25 people with emmetropia (spherical equivalent refraction [SER] +0.21 ± 0.36 diopters [D]) and 45 people with myopia (-2.84 ± 1.72 D). There were 23 people with low myopia (>-3 D) and 22 people with moderate myopia (-3 to -6 D). Right eye ciliary muscles were imaged (Visante OCT; Carl Zeiss Meditec) at 0 D and 6 D demands. Measures included ciliary muscle length (CML), ciliary muscle curved length (CMLarc), maximum ciliary muscle thickness (CMTmax), CMT1, CMT2, and CMT3 (fixed distances 1-3 mm from the scleral spur), CM25, CM50, and CM75 (proportional distances 25%-75%). Linear mixed model analysis determined effects of refractive groups, race, and demand on dimensions. Significance was set at P < 0.05.Results: Myopic eyes had greater CML and CMLarc nasally than emmetropic eyes. Myopic eyes had thicker muscles than emmetropic eyes at nasal positions, except CM25 and CMT3, and at CM75 temporally. During accommodation and only nasally, CML reduced in emmetropic and myopic eyes, and CMLarc reduced in myopic eyes only. During accommodation, both nasally and temporally, muscles thickened anteriorly (CMT1 and CM25) and thinned posteriorly (CMT3 and CM75) except for temporal CM75. Moderate myopic eyes had greater temporal CMLarc than low myopic eyes, and the moderate myopes had thicker muscles both nasally and temporally using fixed and proportional distances.Conclusions: People with myopia had longer and thicker ciliary muscles than people with emmetropia. During accommodation, the anterior muscle thickened and the curved nasal muscle length shortened, more in myopic than in emmetropic eyes. The fixed distance method is recommended for repeat measures in the same individual. The proportional distance method is recommended for comparisons between refractive groups.
KW - Adult
KW - Ciliary Body/physiology
KW - Emmetropia
KW - Humans
KW - Muscle, Smooth
KW - Myopia
KW - Tomography, Optical Coherence
KW - optical coherence tomography
KW - ciliary muscle
KW - accommodation
KW - emmetropia
KW - myopia
UR - http://www.scopus.com/inward/record.url?scp=85133102331&partnerID=8YFLogxK
U2 - 10.1167/iovs.63.6.24
DO - 10.1167/iovs.63.6.24
M3 - Article
C2 - 35749128
SN - 0146-0404
VL - 63
SP - 1
EP - 10
JO - Investigative ophthalmology & visual science
JF - Investigative ophthalmology & visual science
IS - 6
M1 - 24
ER -