First Evaluation of a Retinal Imaging Laser Eyewear System Based Low Vision Aid.
Purpose: We conducted this trial to investigate a new wearable laser-eyewear (LEW). Images of an integrated camera are projected to the retina by a RGB-Laser (<1µW) and MEMS-mirror system. This enables a full-color live video as augmented reality embedded in the field of vision of the wearer. Thin parallel laser beams are projected following the principle of Maxwellian view through the center of the ocular lens to ensure independency of refractive errors. We performed a study with healthy subjects to test this independency.
Materials and methods: LEW was tested in 20 healthy subjects (aged between 21 and 60 years) with hyperopia, myopia, astigmatism and/or presbyopia. Subjects underwent standardized visual acuity (VA) measurements (ETDRS) without any correction, with LEW and with best correction.
Results: We found no significant correlation between refraction and VA while using LEW in linear regression (r=0.17). Still, younger participants performed better in terms of VA with the device compared to older participants despite no differences in BCVA (p<0.01). The achievable VA with LEW was in general reduced compared to uncorrected VA (0.50 vs 0.40 logMAR). Only myopic subjects reached a significantly higher VA using LEW (p<0.001). Presbyopic subjects showed enhanced near VA (0.25 logMAR) by reading at 15cm with LEW without any further necessary refractive correction. Nearly all patients (80%) showed stereopsis without need for additional adjustments.
Conclusion: Our investigation could verify the independence of LEW of refractive errors. Therefore, the technology seems to be especially useful in patients with untreatable corneal conditions, e.g., after corneal burns, to achieve higher VA since the thin laser should penetrate even corneal opacities with less scattering.