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. 2020 Dec;9(4):917-927.
doi: 10.1007/s40123-020-00281-7. Epub 2020 Jul 28.

Twenty-Year Follow-Up of Excimer Laser Photorefractive Keratectomy: A Retrospective Observational Study

Giovanni Cennamo  1 , Feliciana Menna  1 , Fabrizio Sinisi  1 , Gilda Cennamo  1 , Maria Angelica Breve  1 , Pasquale Napolitano  1 , Maddalena De Bernardo  2 , Livio Vitiello  2 , Nicola Rosa  3
Affiliations

Twenty-Year Follow-Up of Excimer Laser Photorefractive Keratectomy: A Retrospective Observational Study

Giovanni Cennamo et al. Ophthalmol Ther. 2020 Dec.

Abstract

Introduction: Photorefractive keratectomy (PRK) was introduced in the late 1980s to correct myopia. The purpose of this study was to assess its long-term efficacy and safety, analyzing patients with at least 20-year follow-up.

Methods: This retrospective observational study was carried out on 85 eyes of 54 patients (33 females) that underwent PRK between 1991 and 1998 (mean age 32.62 ± 9.74, range 18-55 years). Both preoperatively and postoperatively, patients underwent a complete ophthalmological evaluation, including uncorrected and corrected distance visual acuity, slit-lamp, intraocular pressure, dilated fundus, and corneal topographic examinations. The outcome assessment was made by comparing the preoperative refraction, as spherical equivalent, with the postoperative ones, taking into account the planned refractive correction. Safety and efficacy indices were also calculated. All the data were evaluated with a paired t test.

Results: The mean attempted correction as spherical equivalent was - 5.64 ± 3.01 D (range - 1.00 to - 15.00 D), while the mean achieved correction after 20 years was - 4.30 ± 3.13 D (range - 1.88 to - 14.25 D), with a significant statistical difference (p < 0.01). The mean expected refractive outcome was - 0.27 ± 0.81 D (range - 4.00 to + 1.25 D). The mean difference between achieved and attempted treatment was 1.33 ± 1.92 D (range - 4.25 to + 6.25 D), with a significant difference (p < 0.01). The safety index was 1.00 and the efficacy index was 0.63.

Conclusion: The results provided by this study highlight that the procedure could be considered safe, with no long-term sight-threatening complications such as late ectasia or haze.

Keywords: Long-term follow-up; Myopia; PRK; Photorefractive keratectomy.

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Figures

Fig. 1
Fig. 1
Comparison between postoperative UDVA and preoperative CDVA at 20-year follow-up
Fig. 2
Fig. 2
Comparison between postoperative UDVA and preoperative CDVA at 20-year follow-up, considering Snellen chart lines
Fig. 3
Fig. 3
Change between preoperative and postoperative CDVA at 20-year follow-up, considering Snellen chart lines
Fig. 4
Fig. 4
Correlation between the achieved and attempted correction after 20 years. Dotted line, identity line; bold continuous line and bold dashed lines, mean ± standard deviation; dashed-dotted line, regression line
Fig. 5
Fig. 5
Spherical equivalent refraction accuracy in different ranges of achieved correction at 20-year follow-up
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