Session Title: New Drug Treatment and Technology I
Session Date/Time: Friday 18/09/2015 | 11:00-12:30
Paper Time: 12:04
First Author: : H.Kwak KOREA, SOUTH
Co Author(s): : S. Yu
PURPOSE:To evaluate structural changes of the retina following selective retina therapy (SRT) controlled by optical feedback-techniques (OFT) with histology and in-vivo spectral domain optical coherence tomography (SD-OCT).
The study was carried out in Kyung Hee University Hospital, Seoul, Korea.
SRT using a pulsed double-Q-swithched Nd-YLF laser with automatic dosage control system (wave length = 527 nm, duration=1.7 ㎲, repletion rate = 100Hz, Number of pulse in a burst = 30) was applied to 12 eyes of Dutch Belted rabbits. The maximum energy power was 45 µJ and the laser spot size in air is 200㎛. Retinal changes were assessed using fundus photography, fluorescein angiography (FAG), SD-OCT and light microscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) at each time point in 1 hour, 1, 3, 7, 14, 28 days after SRT.
SRT lesions obtained 1 hour after SRT were ophthalmoscopically invisible. FAG showed leakage corresponding to SRT treated lesions and hyperfluorescence disappeared after 7 days. SD-OCT observed that decreased reflectivity correspond to RPE damage return to normal RPE layer over time in SRT treated lesions. In histologic analysis, the damage of SRT treated lesions were limited primarily to retinal pigment epithelium (RPE) and the outer segment of photoreceptor. SEM and TEM disclosed RPE cells showed migrating on 3 days after SRT, and in 1 week there was restoration of RPE monolayer with microvilli. By 14 and 28 days, ultra-structures of RPE including microvilli, tight junction and apical-basal polarity were completely restoration. The outer segments of photoreceptor were recovered without sequelae. Interdigitation between photoreceptor and RPE was observed.
Selective targeting of RPE can be achieved by OFT-controlled SRT without adverse effects to the neurosensory retina.