Value-Based Medicine

How Greatly is Vision Valued?

By Melissa M. Brown, MD, MN, MBA

In the March Value-Based Medicine column, we looked carefully at the value of vision from the perspective of folks with varying levels of visual disability.

We learned that utility varies most directly with the visual level in the better-seeing eye. We are reminded that the mean change in utility when vision improves from "no light perception" to 20/200 is even greater than the large difference appreciated when vision improves from 20/200 to 20/20.

We also appreciated the fact that the value of vision appears to be most related to level of vision rather than to the specific underlying cause of the visual impairment. And that the effect of length of time of visual loss upon utilities is less clear. It appears that patients with AMD, who have an older mean age of disease and may have lost vision precipitously, have a poorer quality of life (QOL) than those with the same visual level but have experienced such a health state for more than a year. Further research needs to be done in this area.

Reviewing, utility ranges from 0.0, representing death in overall health, to 1.0 which reflects permanent, perfect health. The closer the utility to 1.0, the better the quality of life associated with a health state, while the closer it is to 0.0, the poorer the associated quality of life.

Vision Loss vs Other Disabilities

Let's now refer to the accompanying table to see exactly how the value of vision compares with that of other health states.

Certainly it is intriguing that we can compare the QOL of patients experiencing changes in function, pain, mobility, anxiety and so forth due to varying levels of damage due to myocardial infarction, osteoarthritis, cerebral vascular infarctions, diabetes mellitus and the like. Of note, however, is that we can thus measure the effectiveness of medical interventions that improve our function across many dissimilar organ systems.

Of course, it is key that we measure in a standardized manner and with relevant standardized classifications.

As examples, the American College of Rheumatology, Karnofsky Performance Scale and Rankin Classifications are as well known to physicians in the relevant specialties as the Snellen visual acuity classification is to ophthalmologists.

The mean utilities described are helpful in our understanding of how we begin to use value in our assessment of medical interventions. Those interventions that can be shown to demonstrate an improvement in quality of life for our patients will be of most interest. Those interventions that cannot demonstrate their measured improvement of QOL may also become notable.

The comparative effectiveness of our interventions are of increasing interest to our policymakers and, by extension, to our payers of healthcare. It should come as no surprise now, with the new Patient Protection and Affordable Care Act signed into law, that the sighting crosshairs of the newly anointed Patient-Centered Outcomes Research Institute — charged with evaluating effectiveness — will come into focus. OM

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Melissa M. Brown, MD, MN, MBA, is president and CEO of the Center for Value-Based Medicine in Philadelphia, She can be reached via e-mail at mbrown@valuebasedmedicine.com