The age of refractive surgery has introduced new aberrations to the human eye that require a shift in how visual performance is evaluated, said Ray Applegate, MD. Mesopic low contrast acuity best quantifies vision quality; it overcomes the weaknesses of other metrics and it can predict visual function among individuals.
The age of refractive surgery has introduced new aberrations to the human eye that require a shift in how visual performance is evaluated, said Ray Applegate, MD. Mesopic low contrast acuity best quantifies vision quality; it overcomes the weaknesses of other metrics and it can predict visual function among individuals.
Dr Applegate recruited 168 people with 6/6 or better vision across a range of ages and conducted a photopic high-contrast logMAR acuity test. "The test could only account for around 4% of the variation in our sample," he said. "We can't use it to predict the visual function of individuals. However mesopic low-contrast logMAR acuity accounted for a much broader range of the variation."
Dr Applegate said high contrast acuity is a poor metric because it is conducted under high luminance conditions and has excess contrast allowing a loss in contrast and image fidelity without a loss in measured acuity.
Contrast sensitivity, on the other hand, is impractical because it requires measurements along many different orientations. "That is simply not practical in the clinical environment and it is totally insensitive to phase shifts," insisted Applegate.
But mesopic low contrast acuity allows a large physiologic pupil and is sensitive to phase shifts and contrast loss. "It's also a recognition task as opposed to a detection task that's understood by clinicians and patients and it's easy to administer in a clinical setting," he said.
The study will be published shortly in Optometry and Vision Science.
Ophthalmology Times Europe reporting from the XXIV Congress of the ESCRS, London, 9-13 September, 2006.
AAO 2024: Transient vision loss with Alexander Fein, MD
October 21st 2024Alexander Fein, MD, spoke with the Eye Care Network to share how to approach a patient presenting with transient vision loss, what this type of vision loss can mean, and what additional testing might be needed to determine the best plan for care.
AAO 2024: Optimal pupil size reduction percentage for near vision improvement in presbyopia
October 21st 2024Jennifer Loh, MD, shared insights from on her presentation at the American Academy of Ophthalmology meeting in Chicago on the effects of CSF-1, which is the lowest effective concentration of pilocarpine approved in the United States.