A new analysis of data for visual impairment as a function of myopia has helped researchers better understand how myopia control can lower the risk of visual impairment later in life.

Applying a mortality table to a quantitative evidence-based approach comparing myopia control’s risks and benefits resulted in the frequency of visual impairment per 10,000 patients at different levels of myopia. The cumulative risk of visual impairment associated with ultimate levels of myopia of –3D, -5D and –7D was estimated to be 90, 150 and 250 per 10,000 patients, respectively.

“We can integrate the area under those curves, and the area under the curve is patient years of visual impairment,” said Mark A. Bullimore, MCOptom, PhD, dean of the Southern California College of Optometry at Marshall B. Ketchum University, while presenting the research last week at the American Academy of Optometry’s annual meeting in Orlando. “And what we can then see is that if we can lower somebody by a diopter, we can save anywhere from a half to maybe one year of visual impairment in an individual patient.”

“Comparing the benefits and the risks,” Dr. Bullimore explained, “preventing one diopter of myopia through treatment should lower the years of visual impairment by between 5,000 and 10,000 years per 10,000 patients.”

Researchers also developed a mathematical term that encompasses both age and level of myopia that estimates five years of myopia is equivalent to 12 years of aging in terms of risk exposure to the patient.