Active eye-tracking for an adaptive optics scanning laser ophthalmoscope

Abstract

Abstract:We demonstrate a system that combines a tracking scanning laser ophthalmoscope (TSLO) and an adaptive optics scanning laser ophthalmoscope (AOSLO) system resulting in both optical (hardware) and digital (software) eye-tracking capabilities. The hybrid system employs the TSLO for active eye-tracking at a rate up to 960 Hz for real-time stabilization of the AOSLO system. AOSLO videos with active eyetracking signals showed, at most, an amplitude of motion of 0.20 arcminutes for horizontal motion and 0.14 arcminutes for vertical motion. Subsequent real-time digital stabilization limited residual motion to an average of only 0.06 arcminutes (a 95% reduction). By correcting for high amplitude, low frequency drifts of the eye, the active TSLO eye-tracking system enabled the AOSLO system to capture high-resolution retinal images over a larger range of motion than previously possible with just the AOSLO imaging system alone.

Subretinal Injection for Gene Therapy Does Not Cause Clinically Significant Outer Nuclear Layer Thinning in Normal Primate Foveae

“…In our study, significant eye movements in our animals due to light sedation would have made AO imaging very challenging, yet continuous technological improvement in eye-tracking and acquisition speeds might help overcome these limitations. 28 Also, we believe that investigating ways to further reduce retinal stress and cellular damage by optimizing the SRi surgical approach could prove beneficial not only to reduce direct damage to photoreceptors in weaker, disease-affected retinas, but could also by minimizing disruption of the blood-retina barrier and proinflammatory effects of retinal damage. 29 Further optimization of the surgical approach should contribute to the overall safety and efficacy of target cell transduction and long-term transgene expression in the context of gene therapy.…”

Adaptive Optics for Photoreceptor-Targeted Psychophysics

“…Fast software stabilization algorithms have been developed to measure image strip offsets and to correct the AOM timing signals accordingly [74,75]. With this real-time stabilization of fixational eye movements, stimulus positions can be locked onto selected retinal locations, with a residual position jitter of about 0.15 arcmin, an area slightly smaller than the diameter of the smallest photoreceptors [76]. Saccades and microsaccades are too large to be corrected at present, so they must be ignored, or at least recognized when they occur in order to reject any compromised data.…”

“…In some forms of ocular disease, such as retinal dystrophies, normal fixational eye movements are accompanied a b by large nystagmus-type eye movements [95]. While smaller fixational eye movements can be compensated for by hardware or software based image stabilization tools [76,96], larger motion amplitudes can be counteracted by active beam steering [96,97]. An intense pathological nystagmus, however, can considerably prolong the imaging process, degrade image quality, or may render correction impossible completely [43,56,98].…”

Adaptive Optiken – Möglichkeiten für die Diagnostik hereditärer Netzhauterkrankungen

“…Kleinere Fixationsaugenbewegungen können aber, z. B. in SLO-Modalitäten durch hardware-und softwarebasierte Bildstabilisierungsalgorithmen, in nahezu Echtzeit kompensiert werden [81,82]. Augenbewegungen mit größeren Amplituden können in SLO-Systemen durch eine aktive Strahllagenanpassung ausgeglichen werden [81,83].…”