Abstract
Purpose :
Optimal focusing during laser photocoagulation can improve the safety and efficacy of the treatment. We evaluate a method that facilitates laser focusing by incorporating a commonly used focusing optical system into a laser photocoagulation system that can also prompt the operator to adjust the eyepiece for better visibility.
Methods :
In this experiment, a focusing optical system used for devices such as fundus cameras, was incorporated into the delivery optical system of a laser photocoagulator (MC-500 Vixi, NIDEK). The focusing optical system was designed so that the prism pair was conjugate with the fundus, and the aperture was conjugate with the pupil position. The two light rays (split bars) separated by the prism pair can be aligned to form a single straight line at the fundus conjugate position. A single straight line indicates that the laser beam is properly focused at this observation position.
Results :
The formation of a single straight line by the split bars was confirmed at the position conjugate with the fundus. Additionally, a simulation of the appearance of the split bars when the imaging surface is shifted by z (mm) from a position conjugate to the fundus, a separation of the split bars was confirmed at a distance of z ≧ 0.2 mm. If the split bars formed a single straight line and the observed image remained blurred, the operator has to adjust ocular eyepiece to achieve optimal focus and laser targeting.
The poster presentation will also present an appearance of the split bars at the position conjugate to the fundus that was conducted by incorporating the focusing optical system into a slit lamp (SL-2000, NIDEK), and the variation of reproducibility of adjustments of the oculars based on the presence or absence of the focus assisting system.
Conclusions :
The focus assisting system allows proper (and relatively easy) focusing of the laser beam for photocoagulation at the exact location of observation, and the operator can notice whether visibility adjustments should be made or not.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.