Ablation Pattern And Outcomes Of Femtosecond Laser-Assisted Laser-In-Situ Keratomileusis In Hyperopic Eyes

To study the ablation pattern and outcomes in patients with hyperopic refractive error who underwent Femtosecond LASIK using Zeiss VisuMax femtosecond and MEL 90 excimer laser (Carl Zeiss Meditec, Jena, Germany). 

Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi, India

In a prospective case series, the ablation pattern at the flap hinge was observed in 10 eyes of 5 consecutive patients who underwent femtosecond Laser in situ Keratomileusis (LASIK) for hyperopic refractive correction (Preoperative Mean refractive spherical equivalent up to +6.50DS). The mean Best-spectacle corrected distant visual acuity (BSCVA) preoperatively was found to be 0.28±0.21 logMAR Snellen visual acuity. The postoperative observation was documented with Uncorrected Distant Visual Acuity (UDVA), serial Anterior Segment Optical Coherence Tomography (ASOCT) examination, and serial clinical photographs.

It was found that the excimer laser firing created an ablative pattern that included the hinge region of the flap partially, resulting in a step-pattern of ablation at the hinge region in these eyes, causing a localized thinning of the flap. This pattern could also be documented better with an ASOCT, showing, a trough-like depression at the region of the hinge, which regressed in subsequent post-operative examinations. This also had an effect on the mean UDVA on day 1 postoperative day (0.5±0.38 logMAR), which improved gradually at 1 month post-operatively (0.3±0.2 logMAR), with the regressing step-configuration. The final postoperative mean UDVA was comparable with the preoperative BSCVA. (p-value 0.9)

Hyperopic laser ablation might involve the hinge region which might result in suboptimal visual outcomes initially. However, this regresses with time, improving visual outcomes.