Phototherapeutic intrastromal corneal collagen cross-linking (PiXL) for treatment of low-grade myopia: comparison of two different protocols with 12 months' follow-up

Session Details

Session Title: Keratoconus & Secondary Ectasia

Session Date/Time: Sunday 15/09/2019 | 08:00-10:00

Paper Time: 09:39

Venue: Free Paper Forum: Podium 2

First Author: : A.Behndig SWEDEN

Co Author(s): :                                 

Abstract Details

Purpose:

To compare the efficacy and safety of PiXL for low-grade myopia with UV irradiation in central 4.0 and 3.5 mm ring-shaped zones.

Setting:

Department of Clinical Sciences/Ophthalmology, Umeå University, Umeå, Sweden.

Methods:

Twenty-seven low-grade myopic participants were treated with bilateral high-oxygen epi-on PiXL, comparing two UV irradiation protocols. In each participant, one eye was treated with one protocol and the contralateral eye with the other, which was randomized. Uncorrected (UDVA) and corrected visual acuities (CDVA), low-contrast visual acuities, refractive spherical equivalents (SE), endothelial cell count (ECC) and adverse events were analyzed pre- and postoperatively. At 1 day and 1 week the participants were asked which eye had the better subjective vision and which eye had least irritation.

Results:

With the 4-mm ring protocol, UDVA improved by 0.35±0.22 LogMAR and SE by 0.98±0.39D at 12 months (p<0.001). The results were better with the 3.5 mm zone (0.55±0.22 LogMAR and 1.25±34D , respectively, p<0.05), but a larger reduction in low-contrast visual acuity was seen with the latter protocol (p<0.05). The 3.5 mm treated eyes had less irritation at day 1 and best subjective vision at 1 week. The ECC and CDVA remained unchanged. No adverse events occurred.

Conclusions:

Our results indicate that these PiXL protocols are promising non-invasive alternatives to refractive surgery for low-grade myopic patients, with an effect of ≥ 1D in myopic reduction. The results remain stable over a 12-months follow up. Reducing the treatment zone may increase the treatment effect but may also affect the low contrast visual acuity.

Financial Disclosure:

None