Prospective randomised controlled trial comparing sub-threshold micropulse diode laser photocoagulation and conventional green laser for clinically significant diabetic macular oedema.
OBJECTIVE
The study was a prospective randomised controlled double-masked trial performed in two centres to compare sub-threshold micropulse diode laser photocoagulation (MPDL) with conventional green laser photocoagulation (CGL) in the treatment of clinically significant diabetic macular oedema (CSMO).


METHODS
Fifty-three patients (84 eyes) with diabetic CSMO were randomly assigned to MPDL (n = 44) or CGL (n = 40) according to the modified Early Treatment Diabetic Retinopathy Study (ETDRS) protocol. Treatments were performed after baseline and re-treatments were allowed at or after the 4 month visit if necessary. Parameters noted included the best corrected visual acuity (BCVA), colour fundus photographs, central retinal thickness using optical coherence tomography (OCT), vision contrast sensitivity with Pelli-Robson charts and presence of visible laser scars at baseline and at 4 and 12 months. The primary outcome was BCVA at 12 months.


RESULTS
All patients completed 12 months of follow-up after treatment at baseline. There were no statistically significant differences in BCVA, contrast sensitivity and retinal thickness between the two laser modalities at 0, 4 and 12 months. We found that laser scarring was much more apparent with CGL than with the sub-threshold approach (MPDL). Laser scars were identified at the 12 month visits in 13.9% of the MPDL-treated eyes compared with 59.0% of the CGL-treated eyes (p<0.001).


CONCLUSIONS
Sub-threshold micropulse diode laser photocoagulation is equally as effective as CGL treatment for CSMO.


BACKGROUND
ISTRN 90646644.
Figueira
J
J
University Hospital and Institute of Biomedical Research on Light and Image, Faculty of Medicine, University of Coimbra, Portugal.
Khan
J
J
Nunes
S
S
Sivaprasad
S
S
Rosa
A
A
de Abreu
J F
JF
Cunha-Vaz
J G
JG
Chong
N V
NV
D000328:Adult; D000368:Aged; D002921:Cicatrix / Q000209:etiology; D015350:Contrast Sensitivity; D003930:Diabetic Retinopathy / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D017075:Laser Coagulation / Q000009:adverse effects / Q000379:methods*; D008266:Macula Lutea / Q000473:pathology; D008269:Macular Edema / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity