The OPHTHIMUS system
High-pass resolution perimetry  for faster examinations
and more reliable diagnoses

High pass resolution perimetry (HPR) introduces a new principle for visual field examination, made possible by recent advances in the physiology of vision and computer technology. The method utilizes spatially high-pass filtered "vanishing" targets to measure resolution rather than differential light sensitivity, as do all other perimetric systems. Click here to see the list of scientific references. A complete description of the Ophthimus system can be found in the manual

The HPR principle has several advantages.

More informative to the Ophthalmologist

The test results are directly related to the functional state of the visual system. In fact the number of active neural channels can be calculated. By comparison with other sophisticated techniques such as pattern electroretinography (Wanger & Persson 1987) and the photography of defects in the retinal nerve fiber layer (Airaksinen 1998), high- pass resolution perimetry has been shown to be very sensitive and reliable. Yet, the HPR examination is extremely easy to perform. The early and reliable detection of disease reduces the need for repeated examinations to confirm diagnosis. Thus, treatment can be intiated without unnecessary delay.

More Rewarding to the patient

Compared to other preimetric systems, the examination time is considerably reduced, to about 5 minutes for each eye. Continuous feedback helps to improve concentration. The system design ensures that the patient remains relaxed and comfortable throughout the test. Handicapped patients can be examined without having to leave their wheelchair or bed. The patient can intuitively understand the test results, which are graphically presented after the examination. This unique feature enhances motivation for treatment and follow-up.

More productive for the clinic

The computer runs the entire test and is controlled by the operator through commands in plain English, entered with a few keystrokes. Therefore, less than one hour of instruction will suffice for personnel with a basic understanding of visual examinations. The comprehensive manual covers all aspects of system setup and operation. The short examination time triples the perimetrist´s productivity compared to conventional systems.

Flexible Installation

A minimum number of compenents which can be configured in various ways,ensures easy installation in any environment. In fact, there is no need for separate perimetric laboratory:the system can be fitted into the standard examination setup in the ophtalmologist´s office.

Versatility

An ongoing R&D program is your guarantee against obsolescence. Right now a number of other useful tests are already included in the basic package or offered as options. And the computer can be used for many other purposes when not busy with ophthalmic examinations.

Test Description

Hig-pass resolution perimetry uses ring-shaped, spatially high-pass filtered "vanishing" targets to determine resolution over the 30 degree visual field. The targets are presented on a test monitor and the progress of the test can be followed on the computer´s system screen. The computer runs the entire test and adapts automatically to the patient´s reaction time as well to responses to fixation control tests and "blank" and "catch" targets. The patient can, at any time, request a pause by simply holding down the response button.

After a brief introduction, during which the patient is provided with standardized instructions, the actual examination starts with a rapid check for measurable vision in all quadrants. Resolution thresholds are then established for 50 locations. Advanced algorithms enable the continuous use of all avaiable information during the examination. The measurements are automatically repeated for test points showing the patient how he/she has performed. A sophisticated statistical package is avaiable as an option.