The neurological control of the visual process is extremely complex and the pupil movement plays an important role. It
controls the intensity of light entering the eye, is responsible for focusing depth and avoiding undesired paracentral rays.
As such factors vary along the day for each patient individually, allied to the individual answer to determined light
stimulation, it is not possible to predict the pupilar size change along the day, leading to undetermined image quality of
the patient for a pre-existent condition.
Among the clinical and surgical procedures in order to enhance the quality of the visual system of the patient, wave-front
based surgeries are performed and its efficiency is strongly dependent on the pupilar position as well as the area to be
ablated. In order to predict the individual behavior of the pupil change during an ordinary routine of the patient we have
been developing a system to provide means for the personal refractive surgery to be the most efficient as possible.
This work presents a method for monitoring the dynamics of the pupil. The methodology presented in this work provides
measurements of the patient's pupil sizes along an entire day with light intensity conditioned to the one that the patient is
exposed. A prototype has been developed using an eyeglass frame, where a dichroic mirror (70% transmittance) is
attached to the frame, as well as a CMOS camera and an infrared illumination system. The image of the pupil is acquired
every 4 minutes, its transferring is done by wireless serial communication (RS-232) and saved in a flash memory. Image
processing and pupil size determination are done later separately from monitoring. The system is under preliminary tests.
We have developed an automatic keratometer module for slit lamp that provides automatic measurements of the radii of
the corneal curvature. The system projects 72 light spots displayed in a precise circle at the examined cornea. The
displacement and deformation of the reflected image of these light spots are analyzed providing the keratometry.
Measurements in the range of 26,8D - 75D can be obtained and a self-calibration system has been specially designed in
order to keep the system calibrated.
Infrared leds indicate automatically which eye is being examined.
Volunteer patients (492) have been submitted to the system and the results show that our system has a high correlation
factor with the commercially available manual keratometers and the keratometry measurements from a topographer.
Our developed system is 95% in agreement with the corneal topographer (Humphrey - Atlas 995 CZM) and the manual
keratometer (Topcon OM-4).
The system's nominal precision is 0,05mm for the radii of curvature and 1o for the associated axis.