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Trial registered on ANZCTR


Registration number
ACTRN12612000266864
Ethics application status
Approved
Date submitted
5/03/2012
Date registered
6/03/2012
Date last updated
2/11/2012
Type of registration
Retrospectively registered

Titles & IDs
Public title
Outcomes of 400 versus 600 micrometer spot size after single session multispots pattern scan panretinal photocoagulation
Scientific title
The macular thickness changes after single session multispots pattern scan panretinal photocoagulation with 400 versus 600 micrometer spot size in severe diabetic retinopathy, randomized clinical trial
Secondary ID [1] 280073 0
Nil
Universal Trial Number (UTN)
U1111-1128-8868
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
severe diabetic retinopathy (severe nonproliferative and proliferative diabetic retinopathy) 285981 0
Condition category
Condition code
Eye 286171 286171 0 0
Diseases / disorders of the eye

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Arm 1: multispots pattern panretinal photocoagulation using 400 micrometer spot size
Arm 2: multispots pattern panretinal photocoagulation using 600 micrometer spot size
Laser photocoagulation is performed using pattern scan system (Valon pattern laser, Dual laser LTD OY, Vantaa, Finland), which is a Nd-YAG 532 nm laser beam. The parameters are: 1) spot sizes of 200 or 300 micrometer with superquad 160 contact lens (laser spot magnification of 2.0; Volk Optical Inc., Mentor, OH) which equivalent to the retinal lesion size of 400 and 600 micrometer, respectively, 2) duration of 20 ms, 3) grid pattern of 4x4, 4) spot spacing of 1.5 widths apart, 5) intensity of gray-white burn, titrated at the major vascular area, 6) distribution extended from vascular arcade to beyond equator, no closer than 2 disc diameter temporal to fovea, no closer than 1 disc diameter to the nasal optic disc. All treatments are performed under topical anesthesia. Duration of the procedures are approximately 4 to 6 minutes. The re-treatment will be considered at 3 months and 6 months of follow-up. The indications of retreatment are persistence or recurrence of the neovascularization.
Intervention code [1] 284395 0
Treatment: Devices
Comparator / control treatment
Control: multispots pattern panretinal photocoagulation using 400 micrometer spot size
Control group
Active

Outcomes
Primary outcome [1] 286639 0
Macular thickness changes after multispots patter photocoagulation in both groups.
Retinal thickness measurements are performed with SD-OCT (Spectralis; Heidelberg Engineering, CA, USA). Scans are performed in fast high resolution pattern, 1024 x 526 resolution. All scans will be reviewed for the accuracy and manually adjusted by one investigator.
Timepoint [1] 286639 0
6 months
Secondary outcome [1] 296344 0
Visual acuity changes after multispots patter photocoagulation in both groups.
Visual acuity will be recorded in ETDRS letters measured at 6-meter charts.
Timepoint [1] 296344 0
6 months

Eligibility
Key inclusion criteria
severe diabetic retinopathy without macular edema (macular thickness of less than 350 micrometers by SD-OCT)
Minimum age
18 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Previous intraocular surgery
macular thickness before treatment more than 350 micrometers by SD-OCT
Associated disease affecting visual acuity
Hemoglobin A1c more than 15

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
1:1 permuted block allocation to 400 micrometer spot size group or 600 micrometer spot size group were performed by one ophthalmologist who does not involved in this research. The alllocation are kept in the sealed opaque enveloped and only exposed by 1 technician not involved in the study.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Permuted block randomization stratified by sex
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Nil
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis

Recruitment
Recruitment status
Stopped early
Data analysis
Reason for early stopping/withdrawal
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment outside Australia
Country [1] 4182 0
Thailand
State/province [1] 4182 0

Funding & Sponsors
Funding source category [1] 284827 0
Hospital
Name [1] 284827 0
Chiang Mai University Hospital
Address [1] 284827 0
110 Intavarorod Road
Maung
Chiang Mai
Thailand
5010
Country [1] 284827 0
Thailand
Primary sponsor type
Individual
Name
Janejit Choovuthayakorn
Address
110 Intavarorod Road
Maung
Chiang Mai
Thailand
5010
Country
Thailand
Secondary sponsor category [1] 283706 0
Individual
Name [1] 283706 0
Nawat Watanachai
Address [1] 283706 0
110 Intavarorod Road
Maung
Chiang Mai
Thailand
5010
Country [1] 283706 0
Thailand

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 286817 0
Chiang Mai University Hospital Ethic committee
Ethics committee address [1] 286817 0
110 Inravarorod Road
Maung
Chiang Mai
Thailand
50100
Ethics committee country [1] 286817 0
Thailand
Date submitted for ethics approval [1] 286817 0
Approval date [1] 286817 0
09/12/2011
Ethics approval number [1] 286817 0
OPT-11-09-14-13

Summary
Brief summary
Long pulse duration pan retinal photocoagulation has been demonstrated the retinal structure damaged and extensive scar after treatment. The treatment should divided into two sessions to reduce the risk of macular edema. With the new concept of shorter pulse duration for panretinal photocoagulation, the expectency of less tissue damage and less chance of macular edema developed after treatment. The laser session may reduce into one session.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 33864 0
Address 33864 0
Country 33864 0
Phone 33864 0
Fax 33864 0
Email 33864 0
Contact person for public queries
Name 17111 0
Janejit Choovuthayakorn
Address 17111 0
110 Intavarorod Road
Maung
Chiang Mai
Thailand
50100
Country 17111 0
Thailand
Phone 17111 0
+66 53 94 5512
Fax 17111 0
+66 53 94 6121
Email 17111 0
janjitc@yahoo.com
Contact person for scientific queries
Name 8039 0
Nawat Watanachai
Address 8039 0
110 Intavarorod Road
Maung
Chiang Mai
Thailand
50100
Country 8039 0
Thailand
Phone 8039 0
+ 66 94 5512
Fax 8039 0
+ 66 94 6121
Email 8039 0
nwwatanachai@gmail.com

No information has been provided regarding IPD availability
Summary results
No Results