The Changes Under Different Accommodation of Anterior Eye and 3D Crystal Reconstruction.

To Study the Changes Under Different Accommodation of Anterior Eye in People of Different Ages and 3D Crystal Reconstruction.

Accommodation is defined as a dynamic change in the overall refractive power of the eye during near fixation. Despite extensive investigations, the exact nature of human accommodation remains controversial. And recent alternative theories question the original concept of accommodation.Different experts have put forward different hypotheses. The age-related changes that underlie presbyopia are also not fully understood.Because of these unanswered questions, the topic of regulation and presbyopia remains a focus of research.

Study Overview

• Status: Recruiting
• Conditions: Accommodation

Detailed Description

Accommodation is the process by which the eye changes the shape and diopter of the lens to obtain a clear image of an object at different distances. Despite extensive research on regulation, the exact nature of human regulation remains controversial. Age-related changes in presbyopia are also not fully understood. Some studies have shown that a hardening of the lens and an increase in the thickness and diameter of the lens with age can lead to presbyopia. Others believe that the main cause is external lens factors, such as age-related changes in the Angle of lens suspension ligament attachment, reduced ciliary body movement, etc. Due to these unanswered questions, the topic of regulation and presbyopia remains the focus of research. In living humans, modulation studies utilize different imaging modes, and ultrasound biomicroscopy (UBM) and Optical Coherence Tomography(OCT) are particularly important in studying anterior segments and modulation. However, UBM is a contact inspection and requires highly skilled technicians. And UBM cannot image the entire anterior segment in a single capture. Anterior segment OCT (AS-OCT), on the other hand, is non-invasive and provides higher resolution imaging, allowing us to capture the morphology of the anterior segment structures in different populations and the changes of the anterior segment structures in response to regulatory stimuli. Studies have shown that with age, reduced anterior chamber depth, pupil contraction, increased lens thickness, increased lens arch height, and loss of posterior ciliary muscle contraction may be biomarkers of early presbyopia. In this study, anterior segment OCT was used to explore whether there were differences in the structural morphology of the anterior segment in people of different ages, and what changes occurred in the structure of the anterior segment after initiation of regulation.

• Study Type: Observational
• Enrollment (Estimated): 120

Contacts and Locations

• Study Contact: Name: Wen Xu, Phd; Phone Number: +86-13858185223; Email: xuwen2003@zju.edu.cn

Study Locations

• China
  • Zhejiang
    • Hangzhou, Zhejiang, China, 310009
      • Recruiting
      • Second Affiliated Hospital, Zhejiang University School of Medicine
      • Contact: wen xu; Phone Number: 13858185223; Email: xuwen2003@zju.edu.cn
    • Hangzhou, Zhejiang, China, 310009
      • Not yet recruiting
      • Second Affiliated Hospital, Zhejiang University School of Medicine
      • Contact: Wen Xu, Phd; Phone Number: +86-13858185223; Email: xuwen2003@zju.edu.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Probability Sample

Study Population

Age 20-80 years old; Astigmatism ≤-1.50D; Best corrected visual acuity ≥4.9;Excluding other systemic underlying diseases; Have a history of eye surgery; Patients with intraocular lens or aphakia; Patients with strabismus and amblyopia; Pregnant or lactating women; People with mental disorders or neurological diseases who cannot cooperate with the examination;

Description

Inclusion Criteria:

· Patients with astigmatism ≤-1.50D and best corrected visual acuity ≥4.9

Exclusion Criteria:

• Patients with other systemic diseases
• Patients with a history of eye surgery
• Patients with intraocular lens or aphakia
• Patients with strabismus and amblyopia
• Pregnant or lactating women
• People with mental disorders or neurological diseases who cannot cooperate with the examination

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
Group A was 20-40 years old; They were divided into three groups according to age: A, B, and C.Group A was 20-40 years old.
Group B was 40-60 years old; They were divided into three groups according to age: A, B, and C. Group B was 40-60 years old.
Group C was 60-80 years old; They were divided into three groups according to age: A, B, and C. Group C was 60-80 years old.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Central corneal thickness changes during accommodation	Central corneal thickness CCT(μm)	Baseline, after accommodation(30 minutes after using pilocarpine)
peripheral corneal thickness changes during accommodation	peripheral corneal thickness(μm)	Baseline, after accommodation(30 minutes after using pilocarpine)
anterior chamber depth changes during accommodation	anterior chamber depth ACD(mm)	Baseline, after accommodation(30 minutes after using pilocarpine)
anterior chamber Angle Angle changes during accommodation	anterior chamber Angle Angle ACA(°)	Baseline, after accommodation(30 minutes after using pilocarpine)
anterior opening distance changes during accommodation	anterior opening distance AOD(mm)	Baseline, after accommodation(30 minutes after using pilocarpine)
pupil size changes during accommodation	pupil size PD(mm)	Baseline, after accommodation(30 minutes after using pilocarpine)
lens thickness changes during accommodation	lens thickness LT(mm)	Baseline, after accommodation(30 minutes after using pilocarpine)
anterior and posterior surface curvature radius changes during accommodation	anterior and posterior surface curvature radius(mm)	Baseline, after accommodation(30 minutes after using pilocarpine)
lens arch height changes during accommodation	lens arch height LV(mm)	Baseline, after accommodation(30 minutes after using pilocarpine)
lens sagittal height changes during accommodation	lens sagittal height(mm)	Baseline, after accommodation(30 minutes after using pilocarpine)
anterior chamber volume changes during accommodation	anterior chamber volume(mm³)	Baseline, after accommodation(30 minutes after using pilocarpine)
posterior chamber volume changes during accommodation	posterior chamber volume(mm³)	Baseline, after accommodation(30 minutes after using pilocarpine)
crystal equatorial diameter changes during accommodation	crystal equatorial diameter(mm)	Baseline, after accommodation(30 minutes after using pilocarpine)

Collaborators and Investigators

• Sponsor: Second Affiliated Hospital, School of Medicine, Zhejiang University
• Investigators: Principal Investigator: Wen Xu, Phd, Second Affiliated Hospital, School of Medicine, Zhejiang University

Study record dates

Study Major Dates

• Study Start (Actual): November 27, 2024
• Primary Completion (Estimated): December 31, 2028
• Study Completion (Estimated): December 31, 2028

Study Registration Dates

• First Submitted: November 17, 2024
• First Submitted That Met QC Criteria: November 24, 2024
• First Posted (Actual): November 26, 2024

Study Record Updates

• Last Update Posted (Actual): May 23, 2025
• Last Update Submitted That Met QC Criteria: May 19, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: 2024-0939

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No