Abstract
Purpose :
Micropulse laser (ML) represents a subthreshold alternative to anti-vascular endothelial growth factor (VEGF) injections for the treatment of diabetic macular edema (DME). ML alters the metabolic activity and gene expression of the retinal pigment epithelium, changing angiogenesis regulation. Via a retrospective chart review, our study sought to determine the impact of ML in the treatment of DME in our unique patient population at Cook County Hospital (Chicago, IL).
Methods :
ML was performed in foveal-threatening DME by the same physician with the same laser parameters (power 200mw; 0.2ms duration; 200µm; and 5% duty cycle). It was performed in 38 eyes of 30 patients, aged 31-84 years (14 female, 16 male) with the objective of preventing foveal involvement. If there was sight-threatening DME at follow-up, patients were observed, treated with anti-VEGF therapy, or ML was repeated. Paired sample t-tests were conducted between baseline and 1, 3, 6 and 12-month data for logMAR visual acuity, central macular thickness (CMT), and maximal macular thickness (MMT).
Results :
Sixteen of 38 eyes (42%) received intravitreal injections (M=2.56) within 6 months of ML (M=88.75 days after ML). Twenty of 32 eyes (63%) received intravitreal injections (M=3.67) within 12 months of ML (M=148.6 days after ML). Two of these injections were performed solely for proliferative disease.
No statistically significant difference was found between baseline, 6 and 12 months for all endpoints. LogMAR Va remained stable (baseline M=0.255 SD= 0.198, 6 mo M=0.262 SD=0.217 {p>0.775}, 12 mo M=0.272 SD=0.232 {p>0.876}). CMT values at baseline and follow-up were less than 300μm (baseline M=246μm SD=53.16, 6 mo M=247.71μm SD=51.26 {p>0.862}, 12 mo M=244.22μm SD=46.56 {p>0.734}). There was however a trend toward improved MMT, indicating an improvement in foveal-threatening disease (baseline M=447.57μm SD=63.72, 6 mo M=436.20μm SD=51.14 {p>0.403}, 12 mo M=428.39μm SD=75.42 {p>0.505}).
Conclusions :
Our data did not support that ML improves logMAR Va, CMT, or MMT, but it does support ML’s role in stability of DME over time in a population that hasn’t previously been reported on. Given the trend toward improvement in MMT, ML represents an adjunctive treatment modality to prevent foveal involvement of DME in patients with a known high injection burden.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.