Fundus reflectometry for photocoagulation dosimetry.

A dosimetry technique has been developed which utilizes three-wavelength fundus reflectometry, a quantitative model of fundus reflectance, and a model of thermal tissue damage to control photocoagulation lesion size. The fundus reflectance model uses Lambert-Beer's law exponential attenuators to describe the ocular media, retinal pigment epithelium (RPE), and choriocapillaris transmission characteristics while the choroid is described as a Kubelka-Munklike homogeneous scatterer/absorber. Three reflecting layers are included in the model at the retinal inner limiting membrane, Bruch's membrane, and the sclera.

Spectral reflectance of the human ocular fundus.

Reflectance spectra from discrete sites in the human ocular fundus were measured with an experimental reflectometer in the visible and near-infrared parts of the spectrum. The principal study population consisted of ten subjects 22 to 38 years of age with a wide range of degree of fundus melanin pigmentation. Reflectance spectra were obtained from the nasal fundus, the fovea, and an area 2.

A new solid-state, frequency-doubled neodymium-YAG photocoagulation system.

We have developed a solid-state laser system that produces a continuous green monochromatic laser beam of 532 nm by doubling the frequency of a neodymium-YAG laser wavelength of 1064 nm with a potassium-titamyl-phosphate crystal. Photocoagulation burns of equal size and intensity were placed in two rabbit eyes with the solid-state laser system and the regular green argon laser system, respectively, using the same slit-lamp mode of delivery. Histologic findings of lesion sections revealed no important differences between the two systems.

Retinal illuminance using a wide-angle model of the eye.

A computer model of relative retinal illuminance, based on our optical wide-angle model of the eye, is proposed for the cases of Ganzfeld illumination and the Maxwellian view through a range of visual field angles from 0 degrees to 80 degrees. The proposed model is designed to be functionally correct and to represent closely the anatomical parameters of the eye. Unlike earlier proposed models, this model is based on our previously reported measurements of spherical aberration in 100 eyes in vivo and is designed to be correct in the peripheral field and with large pupils.

[A universal laser for intraocular treatment].

The creation of a single apparatus incorporating the different lasers applicable to intraocular pathology derives from the idea of possessing the means, with one device, of objectively comparing the effects and parameters of various lasers in order to pursue a more precise line of treatment. This has led to our fabrication of the universal intraocular laser. The word universal means the ability of the machine to act on each kind of intraocular tissues with all of the various infrared or other-colored radiations, as well as with different modalities.