[Preliminary results of a computerized and stereoscopic system for in vivo pupillometry].
OBJECTIVE
We developed a digital system with accommodation capacities for measurement of the diameter and shape of the in vivo pupil for 10 different levels of illumination intensity, varying from mesopic to photopic.


METHODS
An optical system for conjugating images from an infrared and white light illuminated pupil was designed and mounted using an ophthalmoscope helmet and a typical diving mask as support for a high-resolution and sensitivity CCD. Using an IBM compatible computer sequences of video in AVI format were digitized for several seconds at a mean rate of 30 Hz. Algorithms using principles of image processing were implemented for detection of the pupil edges.


RESULTS
We present preliminary results of this system for a voluntary patient. Data for the horizontal (x) and vertical (y) central position and for the diameter of the pupil were then exported to files that could be read by typical spread sheet programs (Excel).


CONCLUSIONS
In this manner, precise data can be obtained stereoscopically (for both pupils at the same time) for any patient, given that the accommodation process is guaranteed by using a white LED virtual mire located 6 meters from the patient's eye. An electronic board precisely controls the level of illumination. We believe here developed instrument may be useful in certain ophthalmic practices where precise pupil geometric data are needed.
Carvalho
Luis Alberto Vieira de
LA
Departamento de Oftalmologia da Universidade Federal de São Paulo - São Paulo (SP) - Brasil. lavcf@if.sc.usp.br
Paranhos Júnior
Augusto
A
D000221:Adaptation, Ocular / Q000502:physiology*; D000328:Adult; D000465:Algorithms; D004867:Equipment Design; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D007498:Iris / Q000033:anatomy & histology; D008029:Lighting / Q000379:methods; D008297:Male; D055255:Mesopic Vision / Q000502:physiology; D019721:Ophthalmoscopes; D055096:Optical Devices; D010775:Photic Stimulation / Q000379:methods*; D011680:Pupil / Q000502:physiology*; D012984:Software