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Br J Ophthalmol. 2009 Oct;93(10):1341-4. doi: 10.1136/bjo.2008.146712. Epub 2008 Dec 3.

Prospective randomised controlled trial comparing sub-threshold micropulse diode laser photocoagulation and conventional green laser for clinically significant diabetic macular oedema.

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University Hospital and Institute of Biomedical Research on Light and Image, Faculty of Medicine, University of Coimbra, Portugal.



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).


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.


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).


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


ISTRN 90646644.

[Indexed for MEDLINE]

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