Enhanced glaucoma system introduced

October 15, 2010

A portfolio of diagnostic, therapeutic, and data management tools for glaucoma can improve clinical assessment and progression analysis.

Miami-A portfolio of diagnostic, therapeutic, and data management tools for glaucoma can improve clinical assessment and progression analysis, according to Douglas R. Anderson, MD, FARVO.

In recent months, a number of enhancements have been introduced to one manufacturer's (Carl Zeiss Meditec) advanced technologies under the rubric "Glaucoma Solutions." The new offerings are intended to help physicians make more informed treatment decisions from early detection through long-term patient management.

Several of the enhancements affect high-definition optical coherence tomography (HD-OCT) (Cirrus) images. The manufacturer has been developing methods for measuring and studying structures other than the retinal nerve fiber layer (RNFL), such as the cup and center of the optic nerve and the neuroretinal rim of axons, said Dr. Anderson, professor and holder of the Douglas R. Anderson Distinguished Chair in Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami.

Dr. Anderson collaborated on a new method of quantifying optic nerve damage commonly seen in glaucoma.

"These instruments are still in evolution, and part of the development is looking for different measurements, trying to improve on reproducibility and accuracy so that HD-OCT can be used clinically both to make a diagnosis and to see how a person is doing over time with treatment," he said.

The goal is to obtain measurements that are highly accurate and reproducible and that help the eye-care provider make a distinction between whether a person's vision is normal or whether nerve fibers have been lost.

Also of significance, in Dr. Anderson's mind, is the ability of HD-OCT to quantify how many nerve fibers a person has compared with the measurement obtained at a previous or subsequent exam. The number of nerve fibers is determined by measuring the thickness of the RNFL.

That capability to quantify change may turn out to be a more reliable feature than making the initial diagnosis, since the normal number of nerve fibers in a person's eye falls within a wide range, varying from about 750,000 to 1.5 million, he said. A measurement of 1 million nerve fibers in the eye of a patient with glaucoma or suspected glaucoma may seem normal, but not if the total was previously 1.2 million.

Another component of the portfolio is software (Guided Progression Analysis [GPA]) for a proprietary automated perimeter (Humphrey Field Analyzer [HFA]). This software assesses both change from baseline and the rate of change of visual field loss over time. The perimeter assesses the dimmest point of light the patient can see at multiple locations, values that are then analyzed by the software and used for comparison with the results of subsequent tests to monitor the patient's vision.

The software is FDA cleared for the perimeter and the HD-OCT systems.

The Glaucoma Solutions suite also includes a data management system (FORUM) for centralizing and viewing clinical data generated by various ophthalmic instruments.

"[A combined reports enhancement] allows you to look at the results of several different tests at the same time, such as the number of nerve fibers and the patient's vision," he said. Viewed together, the structural and functional information from the perimeter and the HD-OCT could confirm each other and may be especially helpful if linked to an electronic medical record in which the test results are viewed along with the findings of the clinician's examination.

The HFA-Cirrus combined report, available through FORUM 2.5, also includes optic nerve head data in the single page, structure-function summary.

Other recently added features are a raw data synchronization tool that automatically archives patient records after each exam while allowing other instruments and review stations to retrieve these data, and the ability to launch the Cirrus HD-OCT review software from anywhere within FORUM with the single click of a button.

"Before FORUM, the testing machines printed out a report of the results," Dr. Anderson said. "Now, the machine is free to begin testing the next patient, increasing the efficiency of the patients' visits.

"The test results from all the machines can be viewed or printed elsewhere, for example, as you discuss your final conclusions with the patient at the end of the encounter or at the end of the day when you prepare a report to another physician," he added. "Or [you may] contemplate with more leisure a puzzling case and make carefully reasoned decisions with more time than is available during the rush of the moment when trying to keep up with the number of patients who are waiting."

Other technology upgrades to the Glaucoma Solutions offerings include enhanced DICOM connectivity to FORUM as a standard option with the HFA 5.0, and enhanced clinic workflow and more robust GPA analysis through a central HFA database architecture available through FORUM 2.5 Archive.

FYI

Douglas R. Anderson, MD, FARVOPhone: 305/243-5496
E-mail: danderson@med.miami.edu

Dr. Anderson is a consultant for Carl Zeiss Meditec.