Seeing clearly is not the whole story: A VISUMAX 800 KLEx study tracks early visual quality after myopia surgery

Success after refractive surgery is often measured by visual acuity, but patients also care about how comfortable their vision feels in daily life. Glare, halos, haze, blurred vision, and night-vision discomfort can shape the early postoperative experience even when the eye chart looks excellent. A new prospective cohort study published in Eye Discovery by researchers from the Eye and ENT Hospital of Fudan University and collaborating institutions provides a detailed early picture of both objective and subjective visual quality after keratorefractive lenticule extraction using the VISUMAX 800 platform.

KLEx is a minimally invasive, flap-free corneal refractive procedure in which a femtosecond laser creates an intrastromal lenticule that is removed to reshape corneal refractive power. The VISUMAX 800 platform represents a newer generation of femtosecond laser technology, with improvements in workflow, centration support, and cyclotorsion management. While prior studies have supported its safety and refractive performance, the early trajectory of patient-reported visual symptoms has been less well characterized.

The study included 193 eyes from 97 patients with myopia or myopic astigmatism. All patients completed 3 months of follow-up. The investigators assessed uncorrected and corrected distance visual acuity, manifest refraction, corneal topography, ocular wavefront aberrations, and patient-reported symptoms across multiple time points. The questionnaire covered eight visual symptoms: halos, hazy vision, starbursts, glare, blurred vision, focusing difficulty, visual fluctuation, and difficulty judging distance or depth.

The early surgical outcomes were strong. All procedures were completed successfully, and in this cohort, all patients reported satisfaction with the procedure. At 3 months, the efficacy index was 1.07 and the safety index was 1.10. No eye lost two or more lines of corrected distance visual acuity. Among eyes targeted for plano correction, 99% achieved uncorrected distance visual acuity of 1.0 or better, and all eyes were within ±0.50 D of the intended spherical equivalent target. Astigmatism correction was also predictable, with 98% of eyes showing residual astigmatism of 0.50 D or less.

Yet the study also shows why visual quality requires more than standard acuity and refraction metrics. At 3 months, total higher-order aberrations, coma, and trefoil had increased significantly, while spherical aberration remained stable. Patient-reported symptoms followed different recovery patterns. On the first postoperative day, glare, halos, hazy vision, blurred vision, and focusing difficulty all increased compared with baseline. Blurred vision and focusing difficulty had returned to baseline by week 1. Halo symptoms gradually improved and returned to baseline by month 3. Glare improved over time but remained more frequent than before surgery at the final follow-up.

The study further identified different drivers of delayed symptom recovery. Eyes with increased glare symptoms relative to baseline had higher coma aberrations, while eyes with increased halo symptoms relative to baseline tended to have larger scotopic pupil diameters. Multivariable analysis further confirmed coma as an independent factor associated with postoperative glare and scotopic pupil diameter as an independent factor associated with postoperative halos. These findings suggest that preoperative counseling and postoperative interpretation should consider not only refractive error and corneal thickness, but also pupil size, optical aberrations, and baseline visual complaints.

Overall, KLEx using the VISUMAX 800 platform showed excellent early safety, efficacy, predictability, and patient satisfaction in this cohort. Most subjective visual symptoms improved over time, although glare may persist longer than other early symptoms. The findings should be interpreted as an early clinical performance assessment rather than proof that the platform is superior to other systems, because the study had only 3 months of follow-up and no direct comparison group. Longer-term and controlled studies will be needed to define the durability of these outcomes and the full recovery trajectory of visual quality.

DOI:10.1016/j.edisc.2026.100039

Read the full article: https://doi.org/10.1016/j.edisc.2026.100039

About Eye Discovery

Eye Discovery is an open-access, peer-reviewed international academic journal, with ISSN 3117-4167. It is published quarterly by Elsevier and serves as the official journal of Eye & ENT Hospital of Fudan University, China. 

Eye Discovery  is dedicated to creating a high-end platform for ophthalmologists, scientists, and scholars worldwide to focus on innovative achievements in ophthalmology and interdisciplinary fields, and to promote academic dissemination and exchange.

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