Purchase this article with an account.
Stacey S Choi, Elaine Wells-Gray, Matthew P Ohr, Nathan Doble; Retinal Integrity after Short Wavelength Subthreshold Micropulse Laser Therapy for Diabetic Macular Edema. Invest. Ophthalmol. Vis. Sci. 2017;58(8):945.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Subthreshold micropulse laser photocoagulation (SMLP) using 532 and 577 nm wavelengths has recently been proposed as a safer, but equally efficacious treatment for diabetic macular edema (DME). While SMLP appears to be less damaging to the retina compared to the existing modified Early Treatment Diabetic Macular Retinopathy Study (ETDRS) laser, there is much to be understood about its effect to the microstructure of the retina following treatment. This project examines the retinal integrity after SMLP treatment using an adaptive optics (AO) imaging system.
Four DME subjects were imaged with an AO scanning laser ophthalmoscope (SLO) – optical coherence tomography (OCT) system at retinal locations that included the DME and its surround. All were treated using the Iridex IQ 577 (Mountain View, CA) and were followed at 2 time points: pre-treatment and 3 months post-treatment. The same retinal locations were imaged at each time point. Cone inner and outer segment lengths (ISL/OSL) and density were quantified at each location for each time point. Total retinal thickness (TRT) and inner retinal thickness (IRT) measurements were also made to monitor the resolution of the edema.
The DME prior to treatment obscured the view of cones in the AO-SLO images. However, over time, the DME resolved and at 3 months post-treatment, individual cones became clearly visible. For all subjects, the change between the 2 time points for all measurements was small. However, there was a large inter-subject variation, showing more obvious structural changes for some patients than others at the same time point. For example, a 13% reduction in TRT was noted for subject #1 vs. 0.8% increase for subject #3. Similarly, for IRT, the values ranged from 7.5% (subject #2) to -0.6% (subject #3). For the ISL and OSL, the ranges were 1.6% (subject #2) to -8.7% (subject #3) and -0.6% (subject #3) to -8.4% (subject #2) respectively.There was a general trend of an increase in IRT at 3 months post-treatment time point with resolution of the DME.
SMLP appears to be an effective treatment for DME without causing structural damage to the underlying photoreceptor layer. This appears to support the findings of previous studies that SMLP is a safe alternative for treating DME.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
This PDF is available to Subscribers Only