What Is Quality of Vision?

ByKerry D. Solomon, MD

In this new era of customized ablation in refractive surgery, the quality of vision that patients achieve with surgery must be the standard in assessing visual outcomes. Surgeons can no longer rely on 20/20 vision as the benchmark for successful results.

Regardless of the excellent outcomes that can be achieved by refractive surgery, the visual tests that are currently used to analyze patients are performed in darkened rooms with lighted charts that display black letters on white fields. These tests are outdated and have no relevance to how well patients see in the real world because they do not test contrast sensitivity. Additionally, these tests do not take into consideration nighttime vs. daytime conditions. In recent years, it has been my experience that patients are able to detect the most discreet aberrations, such as halos and starbursts, at night (Figures 1A and 1B).

Kerry D. Solomon, MD [photo] Kerry D. Solomon, MD, is professor of ophthalmology at the Storm Eye Institute and medical director at the Magill Research Center and Medical University of South Carolina in Charleston. Dr. Solomon is also a member of the Ocular Surgery News editorial board.

The ideal quality of vision that should be achieved for patients is 20/20 vision day and night with minimal to no aberrations. The ultimate goal for patients should include not only the ability to see without glasses but also a refractive procedure that does not impair a patient’s vision further. One of the worst comments that a surgeon can hear from a patient postoperatively is that the patient is thrilled with his or her LASIK procedure but since surgery, the patient must rely on someone else to drive him or her around at night.

Figures 1A-2

Testing for quality of vision

For distance vision, quality of vision tests should include evaluation of clarity and crispness of images, minimal aberrations and contrast sensitivity. Additionally, tests should evaluate patients in simulated daytime and nighttime driving situations for the ability to discern targets, signs and other objects in conditions such as fog, rain, dusk and bright sun.

Ophthalmic surgeons must understand that not all quality of vision is the same. Patients’ visual needs vary depending on external factors including where the patient lives and works, as well as profession; these factors should be considered when choosing refractive goals.

In a recent study of patients who underwent customized LASIK with LADARVision (Alcon Laboratories, Inc., Fort Worth, Texas), 100% were 20/20 at 1 month, and, at 3 months, 15% to 20% of patients improved to better than 20/20 (unpublished data). Additionally, 70% of patients were within 0.25 D of the preoperative goal, showing that accuracy with LADARVision is exceptional. However, surgeons must look beyond these measures of visual acuity.

To examine quality of vision more closely, we assessed the same patients on higher-order aberrations and contrast sensitivity. We found that at the 1- and 3-month intervals, higher-order aberrations decreased steadily from preoperative levels (Figure 2). At 1 and 3 months, no patients experienced a decrease and a few patients’ contrast sensitivity increased at 1 and 3 months (Figure 3). By reducing higher-order aberrations and improving contrast sensitivity, surgeons can truly affect patients’ quality of vision in all lighting conditions for real-life situations.

Quality of life issues

Patients equate quality of vision with quality of life. Whether a patient is driving a car, reading a phone book or looking at food and medication labels, if a surgeon can make these simple day-to-day activities possible, or even better, he or she has impacted the patient’s quality of life.

Snellen acuity charts alone do not test what is important to patients. As refractive technology continues to advance, the bar on visual testing must be raised to keep up with science. As patients live longer and are more active as they age, their expectations will increase and quality of vision will become the ophthalmic standard.