Test evaluates, quantifies ocular dominance for robust monovision correction

(Image Credit: AdobeStock/Generative ART)

The SimVis Gekko eye dominance strength (EDS; 2EyesVision) test provides a new way for patients to choose the monovision correction in their IOLs and contact lenses that best suits them. According to Daniel S. Durrie, MD, this test not only offers refractive corrections for patients to consider but also evaluates dominance and the strength of the dominance, which is different than the binary standard clinical tests.

Durrie, a refractive surgeon in Kansas City, Missouri, presented the results of a study that evaluated the device at the 2024 American Society of Cataract and Refractive Surgery Annual Meeting in Boston, Massachusetts. The clinical sites that were involved in the study were Vance Thompson Vision in Sioux Falls, South Dakota; Hoopes Vision in Draper, Utah; Pepose Vision Institute in St Louis, Missouri; Waring Vision Institute in Charleston, South Carolina; and ClearSight LASIK in Oklahoma City, Oklahoma.

“The SimVis Gekko visual simulator allows the patient to see the real world through a presbyopic correction in various types of IOLs before implantation,” Durrie said. “The simulator is a wearable, see-through device that enables binocular vision across a wide field of view and is fully programmable.”

SimVis Gekko (Image Credit: 2eyesvision)

Durrie also pointed out that this commercially available device has the potential to be used for various applications. The application studied in this investigation was an evaluation of the use of the SimVis Gekko to measure eye dominance, to measure the eye that should be potentially corrected for far vision, and to measure the eye that should be corrected for near vision when prescribing monovision correction.

An added feature of this process is that clinicians also can evaluate the EDS as a percentage of each eye. “We wanted to see [whether] patients had strong dominance [90%-100%], weak dominance [70%-80%], or equidominance [50%-60%] strength, because there seems to be a great deal of difference among patients [clinically],” he said.

EDS is defined as the percentage of times the patient preferred the test presented to an eye.

Study protocol and results

The 326 patients who participated in the study were asked to perform a preference test using the SimVis Gekko after they were corrected for distance, including whether they chose their preferred option between 2 choices with randomized blur in 1 eye and then the other eye using a +1.5 diopter lens. The test was randomly repeated 10 times, and the average testing time was approximately 2.3 minutes.

Durrie pointed out that with this method, the clinician sees the patient’s preference and how strongly dominant the eye is. “Strong dominance was more common than equidominance or weak dominance, and the setting at which it was performed did not affect either the laterality or EDS score,” he said. “Similar trends also were observed in a cohort of
48 presbyopic patients.”

Specifically, strong EDSs were seen at distance and near, respectively, in 50% and 56% of patients. The respective percentages for weak EDSs were 26% and 21%, and 25% and 22% for equidominance. The patients also showed a slight preference for the right eye.

When the results were compared with the standard hole-in-the-card test, the investigators found that the 2 methods generally did not match. “In 41% of the cases, we found that the eye chosen to be the dominant eye with the hole-in-the-card method [motor dominance] did not match the results from the sensory dominance test with the SimVis Gekko,” Durrie said.

Moreover, Durrie also reported that in 26% of the cases, patients changed from right eye dominance with the hole-in-the-card test to left eye dominance with the SimVis Gekko test. Durrie explained that this indicates that the motor dominance identified through the hole-in-the-card test may not necessarily correspond to the dominant eye preferred for monovision correction. “With the dominance strength measured using the SimVis Gekko test, we can accurately identify the patient’s preferred combination of far and near corrections in a real-world setting,” he said.

The quantification of the ocular dominance for determining the monovision preference is the strong point of the test. “It is not the same to provide monovision correction to a patient who flips the dominance between eyes [vs] somebody who has a clearly dominant eye. The SimVis Gekko can be an essential tool for accurately determining the dominant eye and therefore the optimal visual correction for each patient—whether it’s monovision, modified monovision, multifocal lens correction, or other types of corrections,” Durrie said.

The key takeaways from this study include the following:

• The SimVis Gekko EDS test both evaluates and quantifies eye dominance.
• Further study is needed to evaluate the clinical significance of these new findings and the test’s effect on IOL and contact lenses monovision success, including patient-reported outcomes.
• Ultimately, the hole-in-the-card test does not align with the patient’s preferred dominant eye when seeing the world through monovision correction with the SimVis Gekko EDS test.

Daniel S. Durrie, MD

E: dsdurrie@gmail.com

Durrie is an investigator and consultant for 2EyesVision.