A Trial of China Laser and Surgery Study Glaucoma in Rural China

March 18, 2021 updated by: Congdon Nathan, Sun Yat-sen University

The China Laser and Surgery Study : A Mixed Methods Study With an Random Control Trial Comparing Outcomes From Selective Laser Trabeculoplasty Versus Surgical Treatment (Trabeculectomy) for Glaucoma in Rural China .

Aims and Objectives (Quantitative) Aim: To compare the effectiveness of selective laser trabeculoplasty with trabeculoplasty in lowering the intraocular pressure in patients with medically uncontrolled open angle glaucoma in rural China, taking into account the impact of patient acceptance of each type of treatment

Hypothesis: Mean intraocular pressure after treatment with selective laser trabeculoplasty will be lower than with surgery due to higher acceptance rates among patients randomized to receive this treatment and therefore treatment provided at an earlier stage of disease progression.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Glaucoma is one of the three leading causes of blindness in China. Although this condition can be controlled with medication to lower intraocular pressure , such treatment must continue over a patient's lifetime. This is not practical in resource-poor settings due to cost and inconvenience for patients. Trabeculectomy is the standard treatment offered in rural China but is rarely used because of the following issues:

  1. need for hospitalization, which increases patient expense and inconvenience
  2. high refusal rates by patients for all ocular surgery
  3. high rates of infection due to poor quality instruments and material
  4. need for multiple follow-up visits post-surgery (our earlier work shows a return rate of only 30% 1 month post-surgery among rural patients in China).

A viable alternative for patients in rural China is selective laser trabeculoplasty , based on the following advantages:

  1. simplicity (done as a 5-minute out-patient procedure requiring only topical anaesthesia)
  2. effectiveness (18-32% reduction in intraocular pressure, which is comparable to medication)
  3. safety (complications are rare and do not include serious infectious as with trabeculotemy)
  4. convenience (minimal follow-up, with one visit within 6 weeks post-surgery)
  5. cost-effectiveness (compared to other glaucoma therapies in many settings)
  6. acceptability to patients (due to low-cost out-patient care with easy follow-up).

Study Design (Quantitative) This phase of the proposed China Laser and Surgery Study research project is a multi-centre open-label pragmatic randomised controlled trial.

Expected timeline:

  • Enrolment: 12 months
  • Follow-up: 12 months
  • Data analysis: 4 months

Patient Population and Setting: Patients presenting with glaucoma at rural hospitals (n=4) in Guangdong province, China, all of whom are currently capable of performing trabeculectomy surgery, and have been provided an selective laser trabeculoplasty machine and training in its use.

Sample Size: One hundred ninety patients (95 in each group) will be needed to obtain a power of 0.90, with a two-sided alpha of 0.05. Patients are the unit of randomization. Expected IOP difference between groups of 3.0 mm Hg + 4.0 mmg HG, and a correlation of 0.30 between baseline and final intraocular pressure, allowing for loss to follow up of 30%.

Baseline Data:

aseline data (to be collected prior to determination of eligibility and randomization but after obtaining informed consent) include the following:

  • Presence or absence of relevant pre-existing health conditions (i.e., hypertension, diabetes, cardiovascular disease)

  • Ophthamologic test results

    • Best corrected visual acuity and presenting visual acuity in both eyes
    • Intraocular pressure in both eyes
    • Cup to disk ratio in both eyes
    • presence or absence of visually significant cataract in both eyes; if cataract present in study eye, whether cataract surgery has already been performed
    • degrees of visible Trabecular Meshwork in the study eye on gonioscopy without "dynamic gonioscopy"
  • score on glaucoma knowledge test using a simple, previously validated questionnaire

  • Demographic data

    • date of birth or self-reported age in years
    • sex

  • Contact information

    • Address
    • mobile phone number where can be reached (own or neighbours, etc.)

  • Socioeconomic status

    • completed education in years
    • wealth, as measured by ownership of items on a pre-determined list of 13 common household devices in China
    • job title/description

  • Level of difficulty traveling to hospital with eye clinic

    • distance traveled
    • time spent traveling
    • direct or out-of-pocket costs for travel, meals, etc.

Main analyses:

  • Following requirements for intention-to-treat analyses, we will measure mean intraocular pressure at 12 months comparing the two groups and adjusting for baseline intraocular pressure, including all subjects who accepted and refused treatment (primary analysis, unadjusted). We will also measure intraocular pressure as above, adjusting for cataract surgery, age, gender, prior use of medication, degrees of open angle in study eye at baseline, and severity of glaucoma (Cup to disk ratio) in study eye at baseline (primary analysis, adjusted). Both of the above analyses will be repeated using a per protocol approach (including only patients who accepted their assigned therapy, or secondary analysis).
  • We will test for differences in baseline characteristics by study group with t-tests (for continuous variables) and Chi-square tests (for categorical variables). We will use generalized linear models with Poisson regression (for variables with binary outcomes) and linear regression (for variables with continuous outcomes) to estimate the relative risk for the intervention arm. Multiple imputation in Stata 13.1 (StataCorp, College Station, TX, USA) will be used to address missing data. All statistical analysis will be performed using Stata 13.1. A two-tailed P-value of <0.05 will be considered statistically significant.

Study Type

Interventional

Enrollment (Anticipated)

200

Phase

  • Early Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • China
    • Guangdong
      • Guangzhou, Guangdong, China, 510060
        • Blindness Preventment and Treatment Department

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • diagnosis of glaucoma (Cup to disk ratio, or CDR > 0.6 with optic nerve appearance and/or visual field findings consistent with glaucoma in the study eye)
  • angle configuration > 180° of trabecular meshwork visible in the study eye
  • no previous ocular incisional surgery or ocular laser treatment except refractive or cataract surgery in the study eye
  • Best corrected visual acuity > 6/60 metres in both eyes

Exclusion Criteria:

  • Intraocular pressure > 35 in the study eye
  • Cup to disk ratio > 0.9 in the study eye
  • Inability to give informed consent.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: SLT laser group
  1. selective laser trabeculoplasty for 360 degrees the study eye.
  2. Patients having 1 or 2 quadrants of angle with trabecular meshwork not visible will undergo Laser peripheral iridotomy prior to selective laser trabeculoplasty to maximize the amount of angle visible;
  3. Cataract surgery will be offered if indicated and completed within 3 months of selective laser trabeculoplasty , if accepted by the patient.
  4. Patients will be re-examined every 4 months and selective laser trabeculoplasty performed again according to the above protocol if intraocular pressure exceeds the target (25% reduction from the original intraocular pressure or < 21 mmHg, whichever is lower).
Device: SLT laser
Patients will be offered initial SLT laser by doctors
No Intervention: Standard care group
  • Trabeculectomy as usually performed by the operative surgeon in one eye (study eye).
  • Both Mitomycin and releasable sutures are permitted if indicated in the opinion of the surgeon and s/he can perform and/or has access.
  • Simultaneous cataract surgery is permitted if indicated in the opinion of the operating surgeon.
  • Patients will be re-examined every 4 months， and Timolol 0.5% added bid if intraocular pressure exceeds the target (25% reduction from the original intraocular pressure or < 21 mmHg, whichever is lower)
No Intervention: Drug treatment group
Patients not accepting the offered treatment for the study eye within 3 months will receive topical Timolol 0.5% bid at the usual price, with the prescription to be refilled per usual practice at the hospital (usually monthly).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Intraocular pressure
Time Frame: 12 months
  • intraocular pressure in study eye 12 months after receiving treatment (laser or surgery)
  • the intraocular pressure of patients refusing their allocated intervention will still be recorded at 12 months post-refusal and will be considered in the analysis
  • patients accepting the allocated treatment > 3 months after initial offer of treatment will be considered as having refused and their outcome intraocular pressure will be the last reading prior to treatment
12 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Visual quality of life
Time Frame: 12 months
use the scale "NEI-VQ 25" to assess the patient's visual quality of life
12 months
Satisfaction score
Time Frame: 12 months
Using a Surgical Satisfaction Questionnaire previously validated in rural China
12 months
Cataract surgery
Time Frame: 12 months
Cataract surgery performed in conjunction with allocated treatment (Yes/No)
12 months
Allocated treatment
Time Frame: 12 months
use acceptance questionnaire form to calculate surgical receiving rate
12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sun Yat-sen University

Investigators

  • Principal Investigator: Nathan G Congdon, MD,MPH, Zhongshan Ophthalmic Center, Sun Yat-sen University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

September 1, 2016

Primary Completion (Actual)

December 1, 2019

Study Completion (Actual)

December 1, 2019

Study Registration Dates

First Submitted

April 11, 2016

First Submitted That Met QC Criteria

November 2, 2016

First Posted (Estimate)

November 4, 2016

Study Record Updates

Last Update Posted (Actual)

March 19, 2021

Last Update Submitted That Met QC Criteria

March 18, 2021

Last Verified

November 1, 2016

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • SLT in rural China

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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