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Beam-deflection method of diagnosing impaired vision
BibTeX
@MISC{Frohn_beam-deflectionmethod,
author = {Andreas Frohn and Wolfgang Fink and H. Burkhard Dick and Hans-jürgen Thiel Md},
title = {Beam-deflection method of diagnosing impaired vision},
year = {}
}
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Abstract
We describe a simple method to assign a diagnosis of cataract to patients with obscurely impaired vision as well as to those with mild lens opacities. When the narrowest slit is used in a slitlamp examination, a small beam of light appears on the macula. Routine fundoscopy with the 78.0 diopter lens or a 3-mirror glass is appropriate. If a cataract is present, the beam of light is scattered into several straight lines, distorted lines, or both. This has proved a useful diagnostic tool when the lens appears clear but the patient’s vision is impaired, and extensive examinations such as computer tomography or nuclear magnetic resonance tomography for impaired vision may be avoided. The beam-deflection method uses de-vices that are generally available and can detect cataract in the early stages of develop-ment. J Cataract Refract Surg 2001; 27:994–999 © 2001 ASCRS and ESCRS In cases of mild cataract with faint lens opacities, itmay be difficult to find the cause of obscurely im-paired vision. The ophthalmologist may fail to recognize zones of increased light scattering in the nuclear region of the crystalline lens when brunescence is not present. Thus, unremarkable morphology of the eye compart-ments calls for intensive evaluation including perimetry, electrophysiology, and neuroradiology. These examina-tions may be avoided by using a simple method we de-veloped to clarify the diagnosis of impaired vision caused by cataract. This beam-deflection approach comple-ments the classic methods of investigation, which typi-cally consist of slitlamp examination with lateral light, Scheimpflug imaging,1 and laser scattering.2 During fundus examinations with the 3-mirror glass, we observed that the slitlamp’s beam was de-formed by lens opacities. This phenomenon was only visible at the appropriate slitlamp setting; that is, coaxial light, slightly defocused. This article describes our tech-nique to evaluate vision impaired by cataract, its clinical application, and the optical explanation of the beam-deflection phenomenon.
Keyphrases
impaired vision beam-deflection method simple method 3-mirror glass slitlamp examination fundus examination mild cataract cataract refract surg diopter lens beam-deflection phenomenon unremarkable morphology useful diagnostic tool intensive evaluation lens opacity scheimpflug imaging routine fundoscopy faint lens opacity nuclear region early stage nuclear magnetic resonance tomography small beam classic method im-paired vision slitlamp beam computer tomography patient vision optical explanation beam-deflection approach comple-ments coaxial light increased light extensive examination lateral light several straight line eye compart-ments appropriate slitlamp setting mild lens opacity clinical application
