Fellow eye comparison between alcohol-assisted and single-step transepithelial photorefractive keratectomy: late mid-term outcomes

Abstract

Objective: To compare late mid-term results of two different surgical approaches of surface excimer laser ablation for myopic and astigmatic errors in contralateral eyes of the same patients. Methods: Prospective cohort study. A photorefractive keratectomy technique was performed on the right eye and single-step transepithelial photorefractive keratectomy on the left eye of the same patient, in 2012. Postoperative uncorrected and corrected visual acuities, manifest refraction, contrast sensitivity, objective scatter index, tear film stability assessed by serial measurements of objective scatter index and aberrometry as well as occurrence of haze, were compared between groups of eyes. Results: Thirty-two eyes of 16 patients with a mean time of follow-up of 35.2 +/ - 5.0 months (range 30-46 months) were evaluated. No significant differences were observed in postoperative results (visual acuity, spherical equivalent, defocus equivalent, higher-order aberrations, objective scatter index, tear film stability and contrast sensitivity). Contrast sensitivity tended to be better in transepithelial photorefractive keratectomy technique, under photopic lighting conditions without glare and mesopic conditions both with glare and without glare, however, no statistically significant differences were found. No eye presented corneal haze at the last examination. Conclusion: No statistically significant differences in visual acuity, refractive results, contrast sensitivity, objective scatter index, tear film stability or ocular aberrometry were observed between the two surface ablation techniques.

Keywords: contrast sensitivity; excimer laser; photorefractive keratectomy; refractive surgical procedures; visual acuity.

Fig. 1

Late mid-term visual results in PRK and TransPRK treated eyes: Cumulative percentages of eyes attaining specified cumulative levels of UDVA at the last postoperative follow-up (mean= 35.2 months) in the 2 groups. No statistically significant differences were found (p values shown in the figure calculated using exact Fisher test)

Fig. 2

Contrast sensitivity at spatial frequencies of 1.5, 3.0, 6.0, 12.0 and 18.0 cycles per degree at photopic (superior row) and mesopic (inferior row) conditions, without (left) and with glare (right), at the last follow-up examination (mean:35.2 months after surgery). No statistically significant differences were found