Objective:

To investigate micropulse contiguous grid laser in fovea involved DDME and to correlate SD-OCT structural changes with resolution target visual fields.

Purpose:

To investigate micropulse contiguous grid laser in the treatment of eyes with DDME involving the fovea, and second, to correlate OCT findings with resolution target visual field (RTVF) measurements of threshold acuity at fixation, best acuity measured at any intercept within 6 degrees of fixation (BA6o) and with the global macular acuity (weighted average of all acuities) and with NEI-VFQ 25.

Motivation:

Grid application of continuous wave laser for diffuse edema causes severe scarring of the macular retina that expand with time, and pockmark the central visual field, curtailing adequate performance for real world vision tasks.

Methods:

Retrospective pilot study of sequential eyes treated over all areas of leakage on fluorescein angiography (FA). Prior to and at follow-up every 3 months OCT, FA, and RTVF were performed. OCT images were analyzed for disruption of IS/OS junction, ELM, outer nuclear layer (ONL), and central and paraxial thickness and central cyst size. A self-administered version of the NEI VFQ-25 was performed at 6 month intervals. Primary outcome was change in RTVF Global Macular Acuity (GMA) with secondary outcomes the change in BCVA, OCT, and VFQ.

Results:

78 eyes of 57 patients were followed for at least 12 months after treatment. ETDRS BCVA (initial 0.35+0.23logMAR) improved 0.2logMAR in 15%, and 0.3logMAR in 6%, but declined 0.3logMAR in 4%. RTVF GMA (initial 0.82+0.27logMAR) improved 0.3logMAR in 26%, 0.2logMAR in 19% but with 3% worsening>0.3logMAR. OCT central thickness (initial 295+160um) demonstrated only an average 5.2 um but highly variable(+145um) change, with similar variable changes observed in central or paraxial cyst size (7.4+194.um change). The VFQ demonstrated a significant improvement in 28% of subjects. OCT central or paraxial retinal thickness, or cystoid thickness were not correlated with local RTVF scotoma density, whereas disruption of IS/OS junction and ELM with ONL thinning were most often associated with more severe field defects (>3 SD from age matched normal) and failure to improve following treatment.

Conclusion:

In this study of eyes with diffuse macular edema associated with DR, contiguous micropulse grid laser stabilized edema and central vision with improvement in central visual field in approximately 25% of eyes, but without evidence of lesions or scotomata caused by laser. An intact IS/OS junction, ELM and no ONL thinning were associated with less corresponding visual field impairment and improved treatment prognosis. It is our belief that CW laser treatment should not be used for treatment of central macular edema associated with DR and that best corrected visual acuity and central retinal thickness should not be used to define outcomes of treatment.

Contact Details:

Email: ssinclair@stephensinclairmd.com
Cell Phone: +14848026654

Stephen Sinclair