Transcript Funding Mechanism

Comparison of Modified ETDRS and
Mild Macular Grid Laser
Photocoagulation Strategies for
Diabetic Macular Edema
Sponsored by the National Eye Institute,
National Institutes of Health, U.S. Department of Health and Human
Services
Objective
Compare two laser photocoagulation
techniques:
 Modified ETDRS focal photocoagulation
(mETDRS) to areas of edema
• Direct treatment to microaneurysms
• Grid to diffuse leakage
 Mild macular grid (MMG) laser technique
• small mild burns throughout macula
• in areas with and without edema
• no direct treatment of microaneurysms
Background
Presumed mechanism of focal
photocoagulation include
 Closure of microaneurysms
 Reduced blood flow leading to auto-regulation
and reduced edema
 Improved oxygenation leading to auto-regulation
and reduced edema
 Stimulation of biochemical processes in RPE
Would light widespread laser (mild
macular grid, MMG) to the macula be
effective?
Pilot clinical trial
Study Design
Randomized Clinical Trial (Pilot Study)
Major Eligibility Criteria Assessed:
>18 years old
Type 1 or type 2 diabetes
Study eye meets the following criteria (subjects allowed 2 study eyes):
Best corrected electronic ETDRS visual acuity score of ≥19
Definite retinal thickening on clinical exam due to previously untreated DME
Retinal thickness measured on OCT of 250 μm or more in the central subfield or
300 μm or more in at least 1 of the 4 inner subfields
Had no prior laser or other treatment for DME.
• Subjects with 2 study eyes: 1 eye was randomly assigned to receive
1 treatment and 1 eye was assigned to receive the other.
mETDRS N=162 Eyes
MMG N=161
4
Mild Macular Grid
40 minutes post laser
treatment
6 weeks post laser
treatment
Follow-up and Treatment Schedule
3.5 Month
± 2 Weeks
.
.
.
8 Month
± 4 Weeks
.
.
.
12 Month
± 4 Weeks
Measurements by certified Evaluator
•Best-corrected electronic ETDRS visual
acuity
•OCT-measured retinal thickness
Macular laser photocoagulation was
repeated if DME persisted and such
treatment was warranted in the opinion of
the investigator, according to the treatment
guidelines.
Primary outcome: Change in OCT
Secondary Outcome: Change in visual acuity
(Method: Repeated measures least squares
regression models)
Baseline Demographics and Clinical
Characteristics
mETDRS Group
(N=162 eyes)
MMG Group
(N=161 eyes)
38%
58+11
43%
59+11
White
African-American
Hispanic or Latino
Asian
63%
18%
10%
5%
64%
19%
8%
4%
Other
4%
4%
Subject Characteristics
Gender: Women - N(%)
Age (yrs) - Mean+SD
Race - N(%)
Baseline Demographics and Clinical
Characteristics
Diabetes Type - N(%)
Type 1
Type 2
Duration of Diabetes (years) Mean+SD
HbA1c (%) - Mean+SD
mETDRS
Group
(N=162 eyes)
MMG Group
(N=161
eyes)
7%
93%
14+9
6%
94%
13+8
8.2+1.9
8.2+2.1
Baseline Demographics and Clinical
Characteristics Cont.
Ocular Characteristics
E-ETDRS Visual Acuity (letter score)
- N(%)
> 84: 20/20 or better
83-69: < 20/20 to 20/40
68-49: < 20/40 to 20/100
48-34: < 20/100 to 20/200
33-19: < 20/200-20/400
Mean+SD - letters
mETDRS
Group
(N=162 eyes)
MMG
Group
(N=161 eyes)
27%
47%
22%
20%
57%
17%
4%
0%
4%
2%
74+12
73+14
Baseline Demographics and Clinical
Characteristics Cont.
mETDRS
Group
(N=162 eyes)
MMG
Group
(N=161 eyes)
Central Subfield Thickness
(microns) Mean+SD
335+128
346+118
Maximum retinal thickening
of central and inner
subfields (microns, see text)
Mean+SD
148+122
163+111
Number of eyes with at
least 1 unthickened subfield
- N(%)
60%
55%
OCT
Mean Central Subfield Thickness
Percent Edema Resolved for
Central Subfield Thickness
P=0.56
P=0.23
P=0.29
Percent of Edema Resolved for
Weighted Inner Zone Thickness
P=0.07
P=0.02
P=0.57
Note: Weighted inner zone thickness is a weighted average of
the thickness in the central and 4 inner subfields
Percent of Edema Resolved for
Maximum Retinal Thickening
P=0.26
P=0.93
P=0.57
Note: Maximum thickening is the maximum amount of excess
thickness of the central and 4 inner subfields
Percent of Edema Resolved for
Retinal Volume
P=0.01
P=0.12
P=0.31
Note: Retinal volume is a weighted average of the thickness in
the central, 4 inner and 4 outer subfields converted to mm3
Percent with ≥ 10 Letter
Improvement in Visual Acuity
Percent with ≥ 10 Letter Worsening
in Visual Acuity
Summary
Maximum retinal thickening in the inner
zone (within 1500 microns of macular
center), central subfield thickness,
weighted inner zone thickness and retinal
volume decreased in both groups
MMG less effective than mETDRS in
reducing retinal thickening
Visual acuity similar in both groups