Seven year follow-up after advanced surface ablation with excimer laser for treatment of myopia: long-term outcomes of cooling PRK and LASEK

Session Details

Session Title: Surface Ablations for Correction of Ammetropias

Session Date/Time: Tuesday 16/09/2014 | 08:00-10:30

Paper Time: 09:24

Venue: Auditorium

First Author: : R.Hansen DENMARK

Co Author(s): :    K. Grønbech   N. Lyhne   J. Grauslund   A. Vestergaard     

Abstract Details

Purpose:

To evaluate and compare refractive predictability, uncorrected and corrected distance visual acuity (UDVA and CDVA), corneal haze, corneal densitometry and patient satisfaction up to 7 years after Photorefractive Keratectomy with cooling (cPRK) and Laser-Assisted Sub-epithelial Keratectomy (LASEK) for all degrees of myopia, but in particular high myopia.

Setting:

Department of Ophthalmology, Odense University Hospital, Odense, Denmark.

Methods:

Retrospective follow-up study of eyes treated with cPRK or LASEK for all degrees of myopia from 2007 to 2009 at the Department of Ophthalmology, Odense University Hospital. Inclusion criteria: Age 20-50 years at time of surgery, pre-operative CDVA ≤ 0.10 (logMAR) and no other ocular conditions than myopia with or without astigmatism of maximum 3 D. Exclusion criteria: Pregnancy and eyes having undergone re-treatment. A MEL80 flying-spot excimer laser with eye-tracker (Carl Zeiss Meditec AG, Jena, Germany) was used for photoablation in both procedures. Optical zone size ranged from 5.50 to 6.00 mm in both procedures, and maximum attempted spherical correction was -8.50 D. cPRK was performed as a standard PRK procedure, but with immediately cooling of the treated area with chilled saline (range: 2ºC to 4ºC) for 20 seconds after photoablation. Clinical examinations were performed before surgery and 1 day, 6 weeks, and 5 to 7 years after surgery. Pentacam HR (Oculus, Berlin, Germany) tomography was used to determinate corneal densitometry from epithelium to endothelium in the central 2mm ablation zone. For analysis, high myopia was defined as a spherical equivalent (SE) refraction of -6.00 D or worse.

Results:

In total, 66 cPRK eyes and 55 LASEK eyes completed follow-up examination. Before surgery, 97% of cPRK eyes and 93% of LASEK eyes were highly myopic and SE averaged -7.78±1.51 D (range: -4.50 to -13.00) for cPRK and -7.81±1.89 D (range: -1.75 to -13.00) for LASEK (P=0.75). At final follow-up, 35% of cPRK eyes and 16% of LASEK eyes (P=0.10) were within ±0.5 D of intended refraction, whilst 58% of cPRK eyes and 38% of LASEK eyes (P=0.26) were within ±1.0. The mean difference between attempted and achieved SE refraction was -0.98±0.91 D in cPRK eyes and -1.43±1.07 D in LASEK eyes (P<0.05). In eyes with emmetropia as target refraction, 26% of cPRK eyes and 33% of LASEK eyes (P=1.00) had an UDVA ≤ 0.00 (logMAR) at final follow-up. Also, no cPRK eyes, and 2 LASEK eyes (3.6%) had lost 2 or more lines of CDVA. At final follow-up the mean corneal densitometry was 12.31±0.80 in cPRK eyes and 12.30±0.84 in LASEK eyes (P=0.74), and trace haze was found in 4 cPRK eyes (6%) and 6 LASEK eyes (11%) (P=0.51). Ninetyfive percent of all patients were satisfied or very satisfied with the surgery 5 to 7 years after surgery.

Conclusions:

Both cPRK and LASEK seemed safe up to 7 years after surgery for treatment of myopia and low degrees of astigmatism. Results were comparable concerning visual acuity, corneal haze, corneal densitometry and patient satisfaction, although the long-term predictability of cPRK seemed better.

Financial Interest:

NONE