A recent research paper that followed up patients twenty years after laser eye surgery has demonstrated the procedure is safe and without long term complications. The study did show that there was a slight increase in myopia in younger patients over this time. Early patients were treated at St Thomas' Hospital by Professor John Marshall and others using the then ground breaking technology of laser eye surgery. These results a reassuring evidence for both surgeons and patients that the procedure is safe in the long term. The abstract can be read below.
1. Am J Ophthalmol. 2014 Jun 25. pii: S0002-9394(14)00360-2. doi:
10.1016/j.ajo.2014.06.013. [Epub ahead of print]
Twenty year follow-up of a randomized prospective clinical trial of
excimer laser photorefractive keratectomy.
O'Brart DP(1), Shalchi Z(2), McDonald RJ(2), Patel P(2), Archer TJ(3), Marshall J(4).
PURPOSE: To investigate 20 year efficacy and safety of
Photorefractive Keratectomy (PRK) DESIGN: Long-term observational case series.
METHODS, SETTING: University Hospital STUDY POPULATION: Forty-two patients (42 eyes) who had as part of a randomized, prospective trial undergone PRK 20 years previously are presented. All had received -3.0 or -6.0 diopter (D) corrections with either 5.0 or 6.0 millimeter optical zones or a multi-zone treatment. Mean pre-operative spherical equivalent refractive error (SEQ) was -5.13D (range -2.75 to -8.0D).
OUTCOME MEASURES: Visual acuity, Refractive error, Corneal Topography, Axial length
RESULTS: Between 1 and 20 years there was an increase in mean myopic SEQ of -0.54D (p<0.02). In patients under 40 at time of correction, this increase was -0.92D (p<0.002) with an accompanying increase in variance (p<0.02), while in those over 40 it was -0.08D (p=0.8). In female patients the change was -0.69D (p<0.01), while in males it was -0.26D (p=0.6). The efficacy index at 20 years was 0.49 and the safety index was 0.97. Corrected distance visual acuity (CDVA) improved from 1 to 20 years (p<0.01). 93% of corneas were clear at 20 years. 3
eyes had trace haze. There was an improvement in haze scores between 1 and 20 years (p<0.02). Cornea power remained unchanged between 6 months and 20 years (p=0.4). Axial length increased by a mean of 0.84mm (p<0.0001). There was no ectasia.
CONCLUSIONS: There was a slight but significant increase in myopic SEQ after PRK between 1 and 20 years, particularly in those under 40 at the time of treatment and female patients. Corneal power remained unchanged but axial length increased. The procedure was safe with no long-term sight-threatening complications and improvements in CDVA and corneal transparency with time.
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