Early clinical outcomes and comparison between trans-PRK and PRK, regarding refractive outcome, wound healing, pain intensity and visual recovery time in a real-world setup

Abstract

Purpose: To compare early clinical outcomes of single-step transepithelial photorefractive keratectomy (tPRK) and photorefractive keratectomy (PRK) regarding refractive outcome, visual acuity, wound healing, pain intensity and visual recovery time.d.

Methods: In this prospective clinical observational study 200 eyes of 100 consecutive patients with mild to moderate myopia with or without mild astigmatism were included. One hundred eyes each were either treated with StreamLight™ tPRK or PRK with the WaveLight® EX500 excimer laser. Visual acuity (Decimal) was assessed preoperatively and at day 4, 7 and 6 weeks postoperatively. Wound healing (hours between surgery and complete epithelial closure) was monitored at the slit lamp. At day 4, patients subjectively rated the maximum pain intensity within the last 4 days using a numerical pain rating scale (0-15).

Results: Visual recovery was significantly faster in the tPRK group. At days 4 and 7, the mean monocular UCDVA was significantly better in the tPRK group than in the PRK group (p < 0.001). Four days after surgery 72 % of eyes in the tPRK group but no eye in the PRK had a UCDVA of 0.7 or better. At six weeks postoperatively, a UCDVA of 1.0 or better was achieved in both groups. Complete epithelial wound closure was achieved significantly faster in the tPRK group (p < 0.0001) and maximum pain level within the first 4 days after surgery was significantly lower in the tPRK group (p < 0.0001). No patient had lost a line of BCDVA and no complications or adverse effects were observed.

Conclusions: According to our early clinical results, both treatments options appear to be safe and effective methods for the correction of low to moderate myopia with and without astigmatism. However, in our study, StreamLight™ tPRK offered faster visual recovery and epithelial healing and was associated with less pain compared to PRK. It can therefore be considered a good treatment option for patients who refuse or are not eligible for Femto-LASIK, but at the same time demand a faster and more comfortable recovery time than PRK can offer.

Keywords: Myopia; Pain; Transepithelial PRK; Visual acuity; Visual recovery; Wound healing.

Fig. 1

Typical picture of epithelial abrasion using tPRK with clearly visible margin of the ablation zone (a) and typical picture of epithelial abrasion using an Amoils brush (b)

Fig. 2

Mean monocular UCDVA (decimal) preoperatively and at 4, 7 days and six weeks postoperatively in both treatment groups groups for (a) all eyes, b right eyes, c left eyes. Error bars indicate SD for the mean. UCDVA at day 4 and day 7 was significantly better in the tPRK group (p < 0.001 same level of significance on both days)

Fig. 3

„Off target“ spherical equivalent at 6 weeks after surgery in both treatment groups for (a) all eyes, b right eyes, c left eyes (p > 0,05)

Fig. 4

Time until complete epithelial wound healing in both treatment groups for (a) all eyes, b right eyes, c left eyes. Complete wound closure was achieved significantly faster in the tPRK group (p < 0.001)

Fig. 5

Subjective maximum pain intensity level within the first 4 days after surgery evaluated with a numeric pain rating scale in both treatment groups for (a) all eyes, b right eyes, c left eyes. Patients in the tPRK group experienced significantly less pain (p < 0.001)