Non-damaging laser therapy of the macula: Titration algorithm and tissue response

Daniel Palanker; Daniel Lavinsky; Roopa Dalal; Philip Huie

doi:10.1117/12.2036870

28 February 2014 Non-damaging laser therapy of the macula: Titration algorithm and tissue response

Daniel Palanker, Daniel Lavinsky, Roopa Dalal, Philip Huie

Proceedings Volume 8930, Ophthalmic Technologies XXIV; 893016 (2014) https://doi.org/10.1117/12.2036870
Event: SPIE BiOS, 2014, San Francisco, California, United States

Abstract

Retinal photocoagulation typically results in permanent scarring and scotomata, which limit its applicability to the macula, preclude treatments in the fovea, and restrict the retreatments. Non-damaging approaches to laser therapy have been tested in the past, but the lack of reliable titration and slow treatment paradigms limited their clinical use. We developed and tested a titration algorithm for sub-visible and non-damaging treatments of the retina with pulses sufficiently short to be used with pattern laser scanning. The algorithm based on Arrhenius model of tissue damage optimizes the power and duration for every energy level, relative to the threshold of lesion visibility established during titration (and defined as 100%). Experiments with pigmented rabbits established that lesions in the 50-75% energy range were invisible ophthalmoscopically, but detectable with Fluorescein Angiography and OCT, while at 30% energy there was only very minor damage to the RPE, which recovered within a few days. Patients with Diabetic Macular Edema (DME) and Central Serous Retinopathy (CSR) have been treated over the edematous areas at 30% energy, using 200μm spots with 0.25 diameter spacing. No signs of laser damage have been detected with any imaging modality. In CSR patients, subretinal fluid resolved within 45 days. In DME patients the edema decreased by approximately 150μm over 60 days. After 3-4 months some patients presented with recurrence of edema, and they responded well to retreatment with the same parameters, without any clinically visible damage. This pilot data indicates a possibility of effective and repeatable macular laser therapy below the tissue damage threshold.

Citation Download Citation

Daniel Palanker, Daniel Lavinsky, Roopa Dalal, and Philip Huie "Non-damaging laser therapy of the macula: Titration algorithm and tissue response", Proc. SPIE 8930, Ophthalmic Technologies XXIV, 893016 (28 February 2014); https://doi.org/10.1117/12.2036870

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