Quality of life a factor for study in glaucoma

Living with the diagnosis and being told the diagnosis are areas that need more intensive study to determine their impact on patients, said Henry Jampel, MD. He discussed the various factors that have come under scrutiny over the past decade at the annual meeting of the Association for Research in Vision and Ophthalmology.

"Studying the quality of life in patients with glaucoma is important, because-as with any chronic disease-our goal is to keep the patient feeling good," explained Dr. Jampel, professor of ophthalmology, department of ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore. "In the past, we tended to focus on the outcomes of IOP and visual field changes.

Quality of life is measured or defined by patient response to questionnaires. There are, however, many tools or instruments that clinicians can also use to measure quality of life, such as evaluating utility values in terms of patient preferences for disease states and looking at patient performance on vision-requiring tasks. Specific instruments that can be used are the Short Form-36, a generic tool, and the specific National Eye Institute Visual Function Questionnaire (NEI-VFQ).

Factors that can affect the quality of life in patients with glaucoma are treatment, effects of the disease, and the anxiety and stress related to receiving a diagnosis of glaucoma, a potentially blinding disease, Dr. Jampel explained.

Treatment effects One rationale for the development of the Collaborative Initial Glaucoma Treatment Study (CIGTS) was the observation that many patients were happier after surgery, when they no longer needed to use medications, than they were before surgery. At the time of the conception of the study, available treatments (i.e., pilocarpine and carbonic anhydrase inhibitors) tended to cause adverse effects, so that result was logical.

In CIGTS, patients were randomly assigned to receive medications or to undergo trabeculectomy. The study design also included administration of a quality-of-life questionnaire and a symptoms-and-health-problems checklist.

Most of the patients had early glaucoma and were free of glaucoma-related symptoms when CIGTS started. When the visual field defects were compared with the quality-of-life outcomes at baseline, there was only a weak correlation between the two. Over the course of CIGTS, there was little change in quality-of-life in either patient group, according to Dr. Jampel.

The Ocular Hypertension Treatment Study (OHTS) also indicated that there was no difference in quality of life detected between the groups.

"Overall, there were no demonstrable adverse effects of medical treatment on quality of life in the OHTS," Dr. Jampel said. "In CIGTS, surgical treatment was no worse than medical treatment in the long term. Therefore, current treatments may have a minimal effect on quality of life."

Disease effect The first consideration for disease effect is determining when decreased visual function affects a patient's quality of life. The two possibilities are either early in the disease process or later in the disease process.

Early in the disease process, the typical visual field defect, for example, a mid-peripheral nasal defect, may not be noticed by the patient, but might be detected if a quality-of-life instrument is used. Another possibility is that changes in a quality-of-life instrument become detectable only when there is at least a moderate visual field loss, according to Dr. Jampel.

Regarding the evidence for quality of life being affected in the early stages of visual field loss, Dr. Jampel stated that a 1997 study showed that as the visual field deteriorated the responses to various subscales, such as the driving scale of the NEI-VFQ, also deteriorated and the deterioration seemed to start early in visual field loss and progress linearly.