Study on the Effect of Two Ways of Cycloplegia on Biological Parameters of Ciliary Muscle
Phase: PHASE4
Conditions: Accomodation, Refractive Errors, Myopia, Cycloplegia
Sponsor: Shanghai Eye Disease Prevention and Treatment Center

Study on the effect of two ways of cycloplegia on biological parameters of ciliary
muscle
2022/06/28
Shanghai Eye Diseases Prevention & Treatment Center
Department of Optometry
Research Background
The ciliary muscle exhibited an inward-forward contraction during accommodation1-3,
resulting in a significant thickening of the anterior area of the ciliary muscle3 4. In addition to
ultrasound biomicroscope (UBM), anterior segment optical coherence tomography (AS-OCT)
is also commonly used to study morphological changes in the ciliary muscle. Studies using
AS-OCT
revealed
that
the
posterior
area
of
the
ciliary
muscle
thinned
during
accommodation3-8.
The morphology of the ciliary muscles differs in individuals with refractive errors. Many
researchers found that the ciliary muscle became thicker with an increase of axial length (AL)7
9-11. Some studies suggested that myopia primarily affected the posterior area of the ciliary
muscle5 9 12-15.
Atropine has a ciliary muscle-paralysing effect and causes hyperopic drift. Besides,
atropine has been proven to slow the progression of myopia
16 17. Many studies have
suggested that atropine can increase the thickness of the choroid17-20. However, few studies
have discussed changes in the ciliary muscle after treatment with atropine or other cycloplegic
agents. This study aimed to assess the difference in ciliary muscle morphology before and
after two different cycloplegic agents and explored the influencing factors of ciliary muscle.
1. Croft MA, McDonald JP, Katz A, et al. Extralenticular and lenticular aspects of
accommodation and presbyopia in human versus monkey eyes. Invest Ophthalmol Vis Sci
2013;54(7):5035-48. doi: 10.1167/iovs.12-10846 [published Online First: 2013/06/08]
2. Stachs O, Martin H, Kirchhoff A, et al. Monitoring accommodative ciliary muscle
function
using
three-dimensional
ultrasound.
Graefes
Arch
Clin
Exp
Ophthalmol
2002;240(11):906-12. doi: 10.1007/s00417-002-0551-2 [published Online First: 2002/12/18]
3. Xie X, Sultan W, Corradetti G, et al. Assessing accommodative presbyopic biometric
changes of the entire anterior segment using single swept-source OCT image acquisitions.
Eye (Lond) 2022;36(1):119-28. doi: 10.1038/s41433-020-01363-3 [published Online First:
2021/02/27]
4. Lossing LA, Sinnott LT, Kao CY, et al. Measuring changes in ciliary muscle thickness
with
accommodation
in
young
adults.
Optom
Vis
Sci
2012;89(5):719-26.
doi:
10.1097/OPX.0b013e318252cadc [published Online First: 2012/04/17]
5. Lewis HA, Kao CY, Sinnott LT, et al. Changes in ciliary muscle thickness during
accommodation
in
children.
Optom
Vis
Sci
2012;89(5):727-37.
doi:
10.1097/OPX.0b013e318253de7e [published Online First: 2012/04/17]

6. Mohamed Farouk M, Naito T, Shinomiya K, et al. Observation of Ciliary Body Changes
during
Accommodation
Using
Anterior
OCT.
J
Med
Invest
2018;65(1.2):60-63.
doi:
10.2152/jmi.65.60 [published Online First: 2018/03/30]
7. Richdale K, Bullimore MA, Sinnott LT, et al. The Effect of Age, Accommodation, and
Refractive
Error
on
the
Adult
Human
Eye.
Optom
Vis
Sci
2016;93(1):3-11.
doi:
10.1097/OPX.0000000000000757 [published Online First: 2015/12/26]
8. Chen L, Jin W, Hao X, et al. Dynamic changes of scleral spur length in different
accommodation stimuli states. Sci Rep 2021;11(1):18176. doi: 10.1038/s41598-021-97754-x
[published Online First: 2021/09/15]
9. Oliveira C, Tello C, Liebmann JM, et al. Ciliary body thickness increases with increasing
axial myopia. Am J Ophthalmol 2005;140(2):324-5. doi: 10.1016/j.ajo.2005.01.047 [published
Online First: 2005/08/10]
10. Fernandez-Vigo JI, Shi H, Kudsieh B, et al. Ciliary muscle dimensions by
swept-source optical coherence tomography and correlation study in a large population. Acta
Ophthalmol 2020;98(4):e487-e94. doi: 10.1111/aos.14304 [published Online First: 2019/11/28]
11. Muftuoglu O, Hosal BM, Zilelioglu G. Ciliary body thickness in unilateral high axial
myopia. Eye (Lond) 2009;23(5):1176-81. doi: 10.1038/eye.2008.178 [published Online First:
2008/06/14]
12. Bailey MD, Sinnott LT, Mutti DO. Ciliary body thickness and refractive error in children.
Invest Ophthalmol Vis Sci 2008;49(10):4353-60. doi: 10.1167/iovs.08-2008 [published Online
First: 2008/06/21]
13. Pucker AD, Sinnott LT, Kao CY, et al. Region-specific relationships between refractive
error and ciliary muscle thickness in children. Invest Ophthalmol Vis Sci 2013;54(7):4710-6.
doi: 10.1167/iovs.13-11658 [published Online First: 2013/06/14]
14. Buckhurst H, Gilmartin B, Cubbidge RP, et al. Ocular biometric correlates of ciliary
muscle thickness in human myopia. Ophthalmic Physiol Opt 2013;33(3):294-304. doi:
10.1111/opo.12039 [published Online First: 2013/03/05]
15. Kuchem MK, Sinnott LT, Kao CY, et al. Ciliary muscle thickness in anisometropia.
Optom Vis Sci 2013;90(11):1312-20. doi: 10.1097/OPX.0000000000000070 [published Online
First: 2013/10/09]
16. Wu PC, Chuang MN, Choi J, et al. Update in myopia and treatment strategy of
atropine use in myopia control. Eye (Lond) 2019;33(1):3-13. doi: 10.1038/s41433-018-0139-7
[published Online First: 2018/06/13]
17. Ye L, Li S, Shi Y, et al. Comparisons of atropine versus cyclopentolate cycloplegia in
myopic children. Clin Exp Optom 2021;104(2):143-50. doi: 10.1111/cxo.13128 [published
Online First: 2020/08/28]
18. Nickla DL, Zhu X, Wallman J. Effects of muscarinic agents on chick choroids in intact
eyes and eyecups: evidence for a muscarinic mechanism in choroidal thinning. Ophthalmic

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19. Zhang Z, Zhou Y, Xie Z, et al. The effect of topical atropine on the choroidal thickness
of healthy children. Sci Rep 2016;6:34936. doi: 10.1038/srep34936 [published Online First:
2016/10/08]
20. Sander BP, Collins MJ, Read SA. Short-Term Effect of Low-Dose Atropine and
Hyperopic Defocus on Choroidal Thickness and Axial Length in Young Myopic Adults. J
Ophthalmol
2019;2019:4782536.
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10.1155/2019/4782536
[published
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First:
2019/09/19]
Research purposes
1. To observe the anatomical position and morphological changes of ciliary muscle in
myopic children under two cycloplegic methods
2. To analyze the correlation between the changes of ciliary muscle biological parameters
and the changes of axial length, spherical equivalent, lens power, choroidal thickness, etc.
3. To provide clinical evidence for the role of regulatory factors in the occurrence and
development of myopia
3. Research content
This study was designed as a prospective, randomized controlled clinical study
Grouping
72 people in the 1% atropine group
72 people in the tropicamide group
Children mainly from the optometry clinic of Shanghai Eye Disease Control Center
Inclusion criteria
1. Age from 6 to 12 years old, gender is not limited;
2. Both eyes are in line with the diagnosis of myopic refractive error and the myopia is
0.25D < myopia spherical lens <6.00D, astigmatism <2.00D, binocular anisometropia <3.00D,
and the best corrected distance vision is at least 0.8, near vision at least 0.8;
3. A clear anterior segment image can be obtained through anterior segment OCT;
4. Have normal thinking and language communication skills, and can actively cooperate
with the inspection process;
5. No contraindications to atropine treatment such as acute eye inflammation, dry eye,
keratoconus, diabetes, etc.;
6. Written informed consent of the guardian and the child himself

Exclusion criteria
1.
Combined with neurological diseases and have allergies or contraindications to
cycloplegic drugs or other drugs;
2.
Intraocular pressure ≥21mmHg; history of photosensitivity, glaucoma, blue eye
syndrome, ocular hypertension, and retinal macular lesions or damage;
3.
Patients with chronic eye diseases such as ocular trauma and allergic conjunctivitis;
4.
Those who wear contact lenses and those who use myopia control-related drugs
within 1 month, such as atropine and Xinliuding;
5.
Patients with previous varus trichiasis, severe horn, conjunctiva infection and other
eye diseases;
6.
Insufficient image quality, such as inconsistent field of view, poor image exposure,
inaccurate image focus, stains, shadows or crescent shadows, etc.;
7.
There are systemic diseases;
8.
Epilepsy, mental disorders unable to communicate normally;
9.
Other circumstances judged by the investigator to be unsuitable to participate in the
research
Interventions
The period of recruiting patients 3 months
the intervention period 1 week.
1. 1% atropine group: once a night for 7 consecutive days
2. Tropicamide group: once every 5 minutes, after 3 consecutive instillations, close the
eyes for 20 minutes
Outcome
Main outcomes
Ciliary muscle thickness and position parameters before and after treatment
Secondary outcomes
Spherical equivalent and axial length before and after treatment
Other outcomes
Changes in uncorrected visual acuity, corrected visual acuity, intraocular pressure, pupil
diameter, corneal thickness, anterior chamber depth, lens thickness, and choroid/retina
thickness

security indicators
1. Observe changes in intraocular pressure, headache, nausea and vomiting, etc.
2. Questionnaire survey: self-perceived photophobia, near blurred vision and other side
effects levels
3. Incidence of allergic reactions
Security indicators
1. Observe changes in intraocular pressure, headache, nausea and vomiting, etc.
2. Questionnaire survey: self-perceived photophobia, near blurred vision and other side
effects levels
3. Incidence of allergic reactions
Research methods
Sample size
Select the ciliary muscle apex thickness difference after cycloplegia for sample size
calculation
α (inspection level) = 0.05
β (test power) = 0.90
Lost to follow-up rate/dropout rate is 20%
The ratio of the two groups of samples is 1:1
The final calculated sample size is 72 (1% atropine group) + 72 (Tropicamide group) =
144 (total sample size)
grouping
Generate random numbers through a random number table, divide the random numbers
by the number of groups, and group them according to the remainder
Technical Risk
After cycloplegia, near vision blurring may occur, and there may be temporary eye burning
sensation, stinging pain, and photophobia; for people with near vision blurry, the phenomenon
affecting reading needs to be explained patiently, and the subjects should be informed to keep
correct reading distance.
1% atropine may cause dry mouth, dry skin and mucous membranes, nausea, facial
flushing, palpitations and other symptoms after systemic absorption of atropine. Stop the drug

immediately.
A small number of patients have allergic reactions such as itching, redness, and
conjunctival hyperemia of the eyelids, and the drug should be discontinued immediately.
In
case
of
increased
intraocular
pressure,
headache,
eye
pain
and
vomiting
(manifestations of acute angle-closure glaucoma). The solution is to perform initial slit-lamp
screening in all subjects before dilation, and patients with very narrow angles will not be dilated.
If the subject has symptoms such as increased intraocular pressure, headache, eye pain, etc.,
timely drug treatment.
Expected results
To clarify the changes in the morphology and position of the ciliary muscle and its
influencing factors by different methods of mydriasis in clinical practice