A prospective cohort study from Fudan University Eye and ENT Hospital, China, has offered an early, detailed picture of visual quality after keratorefractive lenticule extraction (KLEx) performed with the VISUMAX 800 femtosecond laser platform.
KLEx is already established as a flap-free, minimally invasive approach for correcting myopia and myopic astigmatism. Traditionally performed with the VISUMAX 500 system, the procedure has evolved with the introduction of the VISUMAX 800, which offers faster docking and lenticule creation, improved cutting efficiency, and integrated surgical guidance. Although early reports have supported its safety and refractive performance, the study authors noted that subjective visual quality – particularly glare and halos – had not been systematically explored after VISUMAX 800-assisted KLEx.
To address this, the team enrolled 193 eyes from 97 consecutive patients with myopia or myopic astigmatism who underwent KLEx between November 2024 and January 2025. The mean spherical equivalent was -4.48 ± 1.66 D. Patients were followed for three months and underwent standardized assessments including visual acuity, manifest refraction, slit-lamp examination, corneal topography, wavefront aberration analysis, and questionnaires on subjective visual symptoms.
The refractive results were strong. All procedures were completed successfully, and overall patient-reported satisfaction reached 100%. The efficacy and safety indices were 1.07 ± 0.11 and 1.10 ± 0.11, respectively, and no eye lost two or more lines of corrected distance visual acuity. Among eyes targeted for plano correction, all achieved uncorrected distance visual acuity of 0.8 or better, while 99%reached 1.0 or better. Predictability was also high: all eyes were within ±0.50 D of the intended spherical equivalent target at three months.
Astigmatic outcomes were similarly encouraging. At three months, 98%of eyes had residual astigmatism of 0.50 D or less, and among eyes with preoperative astigmatism of at least 0.5 D, 97%showed an angle of error within ±15 degrees.
The most distinctive aspect of the study was its longitudinal assessment of patient-reported symptoms. On day one, glare, halos, hazy vision, blurred vision, and focusing difficulties were all more common than before surgery. However, most symptoms improved rapidly. Blurred vision and focusing difficulties returned to baseline by one week. Halos peaked early but gradually diminished, with all halo-related scores returning to baseline by three months. Glare improved over time but remained more common than preoperative levels at the final visit.
The investigators also explored factors associated with delayed symptom recovery. Increased coma was independently associated with surgically induced glare, while larger scotopic pupil diameter was linked with halos.
The study is limited by its three-month follow-up and absence of a direct comparator group, so longer-term and randomized studies are still needed. Even so, the findings suggest that VISUMAX 800-assisted KLEx delivers excellent early safety, efficacy, and predictability, while also highlighting the importance of counselling patients that glare and halos may occur early after surgery, but typically improve over time.
