Retinal Laser Therapy: Mechanisms of Interaction and Tissue Response

Since its introduction nearly 40 years ago, laser photocoagulation remains the standard of care for many ocular disorders. Despite widespread use of lasers in retinal therapy it remains largely unknown how its benefits and deleterious side effects relate to parameters of laser treatment and subsequent retinal healing. Thus strategies to reduce untoward effects of laser therapy while maintaining clinical benefit are highly desirable.

We developed a new method of retinal photocoagulation using Pattern Scanning Laser (PASCAL). In this approach patterns of pulses are applied during the eye fixation time (under half a second) with pulse durations in the range of 10-30 ms. PASCAL is currently in clinical use world-wide for retina and glaucoma. In addition to much faster and less painful delivery of the laser treatment, PASCAL enabled the computer-guided sub-visible treatments and sparked renewed interest in research of photocoagulation.

We recently discovered that dynamics of retinal healing in highly confined laser lesions dramatically differs from that of conventional retinal burns. For these lighter lesions, not only can the inner retina be spared, but photoreceptors migrating into the damaged zone from unaffected areas can restore photoreceptor layer continuity over time, as opposed to formation of permanent scars in the conventional lesions. This way retinal scotomas and scarring can be avoided, thereby ameliorating many side effects of laser photocoagulation, and allowing for re-treatment. We study the mechanisms of retinal response to thermal injury, associated neural plasticity, and its effects on retinal signal processing.

 

 

We study dynamics of retinal photocoagulation and vaporization of pigmented tissue with millisecond and microsecond pulses. Our computational model of retinal hyperthermia helps optimizing the laser treatment parameters for enhancement of the safe therapeutic window of retinal phototherapy.

We work on minimally-traumatic approaches to retinal laser therapy using spatio-temporal beam modulation, and utilizing the effects of retinal plasticity and sub-lethal hyperthermia. We also work on automated and diagnostic image-guided ocular laser therapies with applications to the retina, glaucoma and cataract.