Accession Number : ADA283026


Title :   Gradient Index (GRIN) Lens Multimode Fiber Probe for Laser Induced Breakdown in the Eye


Descriptive Note : Interim rept. 22-23 Jan 1994


Corporate Author : ARMSTRONG LAB BROOKS AFB TX OCCUPATIONAL AND ENVIRONMENTAL HEALTH DIRECTORATE


Personal Author(s) : Toth, Cynthia A ; Hammer, Daniel X ; Slawinski, Kim


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a283026.pdf


Report Date : 23 Jan 1994


Pagination or Media Count : 16


Abstract : A model laser surgical probe was designed and built to employ laser induced breakdown (LIB) in cutting fibrovascular membranes within the vitreous cavity of the eye. Current surgical techniques for removing such membranes from eyes with severe proliferative diabetic retinopathy or similar proliferative retinopathies involve cutting the membranes with microscissors or other micro- cutting devices. The mechanical movement of scissor blades may damage adjacent tissues directly or by shearing and traction. A laser cutting system that uses optical breakdown would reduce such mechanical damage but may introduce collateral laser damage. The probe is a simple design of a gradient index (GRIN) lens attached to the tip of a multimode fiber. It is designed to fit through a sclerotomy incision and enter the vitreous cavity for work anterior to the retina. The laser light is focused close to the tip of the probe without causing GRIN lens damage. Thus a widely divergent beam behind the focus will diminish potential laser damage posterior to the target tissue. A Nd:YAG 1064 nm 10ns pulsed laser was used with the probe inserted into a cell of tap water. Threshold data for laser induced breakdown was taken and fit to a probit curve. The data was compared with past LIB threshold data


Descriptors :   *EYE SAFETY , *SURGERY , REPRINTS , PROBES , RETINA , OPHTHALMOLOGY , CORNEA , LASER MEDICAL DIAGNOSIS , LASER DAMAGE , EXPOSURE(PHYSIOLOGY) , MEMBRANES(BIOLOGY) , REFRACTIVE INDEX


Subject Categories : Medicine and Medical Research
      Lasers and Masers


Distribution Statement : APPROVED FOR PUBLIC RELEASE