Korean J Ophthalmol.  2014 Oct;28(5):379-385. 10.3341/kjo.2014.28.5.379.

The Short-term Efficacy of Subthreshold Micropulse Yellow (577-nm) Laser Photocoagulation for Diabetic Macular Edema

• Kwon YH
• Lee DK
• Kwon OW

• KMID: 2344261
• DOI: http://doi.org/10.3341/kjo.2014.28.5.379

Abstract

PURPOSE
This pilot study aimed to evaluate the efficacy and safety of subthreshold micropulse yellow (577-nm) laser photocoagulation (SMYLP) in the treatment of diabetic macular edema (DME).
METHODS
We reviewed 14 eyes of 12 patients with DME who underwent SMYLP with a 15% duty cycle at an energy level immediately below that of the test burn. The laser exposure time was 20 ms and the spot diameter was 100 microm. Laser pulses were administered in a confluent, repetitive manner with a 3 x 3 pattern mode.
RESULTS
The mean follow-up time was 7.9 ± 1.6 months. The baseline-corrected visual acuity was 0.51 ± 0.42 logarithm of the minimum angle of resolution (logMAR), which was improved to 0.40 ± 0.35 logMAR (p = 0.025) at the final follow-up. The central macular thickness at baseline was 385.0 ± 111.0 microm; this value changed to 327.0 ± 87.7 microm (p = 0.055) at the final follow-up.
CONCLUSIONS
SMYLP showed short-term efficacy in the treatment of DME and did not result in retinal damage. However, prospective, comparative studies are needed to better evaluate the efficacy and safety of this treatment.

Keyword

Diabetic retinopathy; Laser therapy; Macular edema

MeSH Terms

Aged
Diabetic Retinopathy/diagnosis/physiopathology/*surgery
Female
Fluorescein Angiography
Follow-Up Studies
Humans
*Laser Coagulation
Lasers, Semiconductor/*therapeutic use
Macular Edema/diagnosis/physiopathology/*surgery
Male
Middle Aged
Pilot Projects
Tomography, Optical Coherence
Treatment Outcome
Visual Acuity/physiology

Figure

• 

  Fig. 1 Color fundus photograph of patient's right eye with diabetic macular edema (A). Subthreshold micropulse yellow laser photocoagulation site shown on a color fundus photograph (B). Laser shots were delivered at the same time with a 3 × 3 pattern mode (multiple squares with yellow dashed line) over the entire area of macular edema including the foveal center. Additional laser shots were applied on other edematous retinal areas.

• 

  Fig. 2 Color fundus photographs and spectral domain optical coherence tomography images of the macula for case 1. The right eye of a 63-year-old woman before (A,B) and after subthreshold micropulse yellow laser photocoagulation (C-L).

• 

  Fig. 3 Changes in logarithm of the minimum angle of resolution (logMAR) visual acuity (VA) (A) and central macular thickness (CMT) (B).

• 

  Fig. 4 Baseline fundus color photographs, red-free photographs, autofluorescence (AF) and fluorescein angiography (FA) images for (A) case 1; (B) shows images of the same patient 14 months after subthreshold micropulse yellow laser photocoagulation (SMYLP; note the invisible chorioretinal scar in the color photograph, red-free photograph, and AF images, and the reduced fluorescein leakage in the FA image); (C) shows case 2 before treatment and (D) shows images of the same patient six months after SMYLP treatment (note that there is no chorioretinal damage in any of the images and an improved petaloid pattern of hyperfluorescence is observed in the AF and FA images).

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