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

One-Year Results of a Phase I/II Randomized, Double-Masked, Placebo-Controlled Study of Processed Amniotic Fluid Drops After PRK

PURPOSE

The aim of this study was to evaluate the 1-year outcomes of using processed amniotic fluid (pAF) postoperatively after photorefractive keratectomy (PRK).

METHODS

Sixty-one participants were randomized to receive either placebo or pAF drops. The drops were instilled 4 times daily for 1 week after PRK along with routine postoperative medications. The primary outcome measures included uncorrected visual acuity, topographic corneal irregularity measurement, and surface staining over 1 year.

RESULTS

A statistically significant difference in uncorrected distance visual acuity between the placebo and treatment groups was seen at 1 month post-PRK, with a visual advantage evident in the pAF group. A suggestive difference in corneal irregularity measurement was also seen between the placebo and treatment groups at 1 month postsurgery, with less irregularity noted in the pAF group. No differences in uncorrected distance visual acuity or corneal irregularity measurement were found at 3, 6, and 12 months. There was also no significant difference in corneal staining scores between the 2 groups at any of the measured time points.

CONCLUSIONS

This 1-year study evaluating the safety and efficacy of pAF as an additional postoperative topical medication after PRK demonstrated that pAF offered a mild visual advantage at 1 month post-PRK. There were no late adverse events, and the intervention proved safe at 1 year.

Tear Proteins Altered in Patients with Persistent Eye Pain after Refractive Surgery: Biomarker Candidate Discovery

Some patients develop persistent eye pain after refractive surgery, but factors that cause or sustain pain are unknown. We tested whether tear proteins of patients with pain 3 months after surgery differ from those of patients without pain. Patients undergoing refractive surgery (laser in situ keratomileusis or photorefractive keratectomy ) were recruited from 2 clinics, and tears were collected 3 months after surgery. Participants rated their eye pain using a numerical rating scale (NRS, 0-10; no pain-worst pain) at baseline, 1 day, and 3 months after surgery. Using tandem mass tag proteomic analysis, we examined tears from patients with pain [NRS ≥ 3 at 3 months (n = 16)] and patients with no pain [NRS ≤ 1 at 3 months (n = 32)] after surgery. A subset of proteins (83 of 2748 detected, 3.0%) were associated with pain 3 months after surgery. High-dimensional statistical models showed that the magnitude of differential expression was not the only important factor in classifying tear samples from pain patients. Models utilizing 3 or 4 proteins had better classification performance than single proteins and represented differences in both directions (higher or lower in pain). Thus, patterns of protein differences may serve as biomarkers of postsurgical eye pain as well as potential therapeutic targets.

Comparison of Objective Visual Quality Following SMILE and SmartPulse Technology-Assisted TransPRK at a 1,050-Hz Ablation Frequency for Moderate-to-High Myopia

PURPOSE

To compare the objective visual quality of moderate-to-high myopia corrected by small incision lenticule extraction (SMILE) and transepithelial photorefractive keratectomy (TransPRK) at a 1,050-Hz ablation frequency, assisted by Smart-Pulse technology (SCHWIND eye-tech-solutions).

METHODS

This study involved 123 patients (123 eyes) with moderate-to-high myopia between July 2020 and January 2021. They were categorized into the SMILE group (67 patients, 67 eyes) and the TransPRK group (56 patients, 56 eyes). Follow-ups were conducted at 6 months postoperatively to record the logarithm of the minimum angle of resolution visual acuity, and the Strehl ratio and higher order aberrations were measured using the Sirius anterior segment analysis device (SCHWIND eye-tech-solutions) under a 6-mm pupil diameter at various postoperative intervals.

RESULTS

At 1 week and 1 month postoperatively, the uncorrected distance visual acuity (UDVA) in the SMILE group was superior to that in the TransPRK group (P < .05 for both). At 1 week and 1 month postoperatively, the Strehl ratio value in the SMILE group was higher than that in the TransPRK group (P < .05 for both). At 1, 3, and 6 months postoperatively, coma was greater in the SMILE group than in the TransPRK group (P < .05 for all). Spherical aberrations were lower in the SMILE group than in the TransPRK group at 3 and 6 months postoperatively (P < .05). At 6 months postoperatively, UDVA was -0.09 ± 0.08 and -0.11 ± 0.05 logMAR in the SMILE and TransPRK groups, respectively, which exceeded their preoperative corrected distance visual acuity of -0.05 ± 0.04 and -0.09 ± 0.08 logMAR (all P < .001). Compared with preoperative values, the Strehl ratio, total higher order, coma, and spherical aberration differences were significantly increased postoperatively in both groups (all P < .001).

CONCLUSIONS

Both surgical methods improved UDVA and each had its advantages. The visual quality of SMILE was superior at 1 week and 1 month postoperatively (Strehl ratio values were higher than those of the TransPRK group), and its spherical aberration was lower than that of the TransPRK group at 3 and 6 months; TransPRK with SmartPulse technology with a 1,050-Hz ablation frequency showed that coma was significantly lower than that of the SMILE group at 1, 3, and 6 months postoperatively. [J Refract Surg. 2024;40(7):e490-e498.].

Clinical Outcomes of Transepithelial Photorefractive Keratectomy Performed with Smart Pulse Technology for the Correction of Moderate to High Myopia

Purpose: To evaluate the safety and efficacy of the transepithelial photorefractive keratectomy (TransPRK) performed using smart pulse technology (SPT) in myopic eyes with refractive error ranging from -5.25 D to -9.75 D. Methods: This retrospective study evaluated the outcomes of SPT-assisted TransPRK in 150 eyes performed using a 1050 Hz AMARIS excimer laser. Results: At 6 months postoperative, 98% of eyes achieved uncorrected distance visual acuity (UDVA) of 20/25 or better, and postoperative UDVA within one line of preoperative corrected distance visual acuity (CDVA). No eyes lost any line of CDVA. Residual spherical equivalent refraction and cylinder within ±0.50 D of intended correction were achieved in 72% and 67% of eyes, respectively. Ninety-seven percent of eyes reported no halos and glare. Conclusions: TransPRK using a 1050 Hz excimer laser with SPT showed excellent predictability, safety, and efficacy for moderate to high myopia correction.

Advances in Transepithelial Photorefractive Keratectomy versus Laser-Assisted In Situ Keratomileusis

(1) Background: Laser-assisted refractive surgery is a safe and effective surgical correction of refractive error. For most patients, both the newer Trans-PRK and the established LASIK technique can produce the required surgical correction, sparking the question of which technique should be opted for. (2) Methods: The study prospectively evaluated 121 patients (230 eyes) for at least one month postoperatively; 66 patients (126 eyes) and 45 patients (85 eyes) returned for 6 months and 1 year follow-up. (3) Results: No statistical difference was recorded at 1 week or 1 month post-operation. At 6 months, a difference was found for spherical diopters (Trans-PRK -0.0476 ± 0.7012 versus FS-LASIK +0.425 ± 0.874, p = 0.004) and spherical equivalent (Trans-PRK -0.1994 ± 0.0294 versus FS-LASIK +0.225 ± 0.646, p = 0.025) but not for CYL D (Trans-PRK -0.3036 ± 0.5251 versus FS-LASIK -0.4 ± 0.820, p = 0.499). Uncorrected visual acuity was better for Trans-PRK 6 months post-operation (UCVA logMAR 0.02523 versus 0.0768 logMAR; p = 0.015 logMAR). At 1-year, Trans-PRK was favored for spherical diopters (Trans-PRK -0.0294 ± 0.6493 versus FS-LASIK +0.646 ± 0.909, p < 0.001) and spherical equivalent (Trans-PRK -0.218 ± 0.784 versus FS-LASIK 0.372 ± 1.08, p = 0.007). Overall speed in visual recovery, variance of results and surgically induced astigmatism were in favor of Trans-PRK. (4) Conclusions: The study reported improvements for Trans-PRK patients, with both techniques found to be safe and effective.

Corneal Irregularity Induced by Transepithelial Photorefractive Keratectomy in a Patient With Partial Limbal Stem Cell Deficiency

PURPOSE

The aim of this study was to present a case of transepithelial photorefractive keratectomy (trans-PRK) laser ablation in a patient with partial limbal stem cell deficiency (LSCD) that resulted in corneal irregularity.

METHODS

A 23-year-old man with bilateral partial LSCD underwent trans-PRK for myopia correction 2 months before presentation to our department. Trans-PRK ablation was performed with a phototherapeutic keratectomy ablation profile set at 60 μm in the OD and 57 μm in the OS and 8 mm zone. At the time of presentation, the patient complained of decreased visual acuity. Corrected distant visual acuity was 20/20 (-3.25, -0.75 × 180 degrees) and 20/50 (-3.00, -3.00 × 180 degrees) in the OD and the OS, respectively. No further ocular history was reported other than prolonged soft contact lens use for myopia. Pre-trans-PRK tomography (WaveLight Oculyzer II diagnostic system, WaveLight GmbH, Germany) revealed bilateral superior steepening with corresponding epithelial thinning as obtained by the epithelial map using Optovue optical coherence tomography (Visionix Luneau technology). Slit-lamp examination showed bilateral superficial neovascularization, suggestive of early-stage LSCD.

RESULTS

A nonuniform laser stromal ablation resulting in corneal irregularity and decreased visual acuity was observed 2 months postoperatively. During the 6-month follow-up, corneal tomography was stable with only minimal improvement. At that time, corrected distant visual acuity remained 20/20 (-2.75, -0.75 × 160 degrees) in the OD and 20/50 (-3.00, -3.00 × 180 degrees) in the OS.

CONCLUSIONS

Trans-PRK seems to be a contraindication in cases with corneal epithelial irregularities and could lead to abnormal and nonuniform stromal ablation .

Investigation of corneal epithelial thickness and irregularity by optical coherence tomography after transepithelial photorefractive keratectomy

CLINICAL RELEVANCE

Corneal epithelial healing after refractive surgery is a clinically significant issue, especially for surface ablation procedures, and this can be monitored using optical coherence tomography (OCT).

BACKGROUND

The aim of this work is to investigate the corneal epithelial thickness and irregularity by OCT after transepithelial photorefractive keratectomy (t-PRK) and analyse its correlation with visual and refractive outcomes.

METHODS

Patients aged ≥18 years with myopia, with or without astigmatism, who underwent t-PRK between May 2020 and August 2021 were included. All participants were subjected to complete ophthalmic examinations and OCT pachymetry at every follow-up visit. Patients were followed up at 1 week and 1, 3, and 6 months postoperatively.

RESULTS

A total of 67 patients (126 eyes) were enrolled in this study. One month postoperatively, spherical equivalent refraction and visual acuity achieved preliminary stability. However, central corneal epithelial thickness (CCET) and standard deviation of the corneal epithelial thickness (SDcet) took 3-6 months to progressive recovery. Patients with higher baseline spherical equivalent refraction were associated with slower epithelial recovery. At every follow-up time point, a significant superior-inferior difference in the minimum corneal epithelial thickness area was observed. Higher stromal haze was correlated with higher spherical equivalent refraction (both baseline and residual) but had no relation with visual outcomes. There was a significant correlation between higher CCET with a better uncorrected distance visual acuity and lower corneal epithelial thickness irregularity.

CONCLUSIONS

CCET and SDcet measured by OCT seem to be a good auxiliary indicator for reflecting the status of corneal wound recovery after t-PRK surgery. However, a well-designed randomised control study is needed to confirm the study results.

Transepithelial photorefractive keratectomy: a prospective randomized comparative study between the two-step and the single-step techniques

OBJECTIVES

To assess and compare the six-month outcome of the two-step transepithelial phototherapeutic keratectomy- photorefractive keratectomy (PTK-PRK) and the single-step transepithelial PRK for myopia and myopic astigmatism.

METHODS

A prospective randomized study. The study enrolled 100 eyes of 50 patients with mild to moderate myopia or myopic astigmatism stratified into two groups, PTK-PRK (n = 50 eyes) and single step PRK (n = 50 eyes). Primary outcome measures were visual acuity and manifest refraction. Secondary outcome measures were epithelial healing duration, post-PRK pain scores and 3-month postoperative haze grading.

RESULTS

Preoperative characteristics were similar in both groups (p value > 0.05). The mean uncorrected distance visual acuity (UDVA) at 1 week, 1 month, 3 and 6 months was significantly better in the single-step PRK group than in the two-step PTK-PRK group (p < 0.001). The mean manifest sphere, cylinder and spherical equivalent showed a significant difference at all follow up visits in favour of the single-step PRK (p value < 0.001). Epithelial healing duration was faster in single-step PRK (p value < 0.001). Pain scores were significantly lower following single-step PRK at 8 h, 1 day, 3 days (p value < 0.001) but were similar at the 7th day. Haze scores showed no statistical difference between the two groups at 3-month follow-up.

CONCLUSION

The two transepithelial PRK techniques were effective in correcting mild to moderate myopia and myopic astigmatism. However, Single-step transepithelial PRK achieved faster visual recovery, better refractive outcome and shorter epithelial healing time with less post-PRK pain.

CLINICAL TRIALS REGISTRY

(Clinical Trials.gov Identifier): NCT04710082.

Outcomes of Single-Step Transepithelial Photorefractive Keratectomy Compared With Alcohol-Assisted Photorefractive Keratectomy Using Wave-Light EX500 Platform

Purpose To compare the visual outcome of transepithelial photorefractive keratectomy (PRK) against alcohol-assisted PRK in treating low-to-moderate myopia with or without astigmatism. Setting Dhahran Eye Specialist Hospital, Dhahran, Saudi Arabia. Design This is a retrospective study. Methods Forty eyes of 22 patients with myopia from -0.75 to -6.00 diopters (D) with or without astigmatism from 0 to -3D were included in this study. Preoperative and postoperative data of 20 eyes from 11 patients who underwent transepithelial PRK were compared with 20 eyes from 11 patients who underwent alcohol-assisted PRK were collected and analyzed. The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest spherical equivalence (SE), manifest cylinder, vector analysis of astigmatism, and efficacy and safety indices were compared between the groups at a mean follow-up of one year postoperatively. Results Baseline characteristics were similar between groups, except the transepithelial PRK group had lower cylinder values than the alcohol-assisted PRK group by 0.69D. Regression analysis was used to control for the difference in the cylinder in all outcome parameters. Both groups had similar mean UDVA (p=0.73), CDVA (p=0.98), the proportion of eyes in either group achieved (20/20, 20/25, and 20/30) UDVA (p=0.72, 0.68 and 0.31 respectively) and percentage of eyes lost two lines of CDVA (p=1.0). There was no statistically significant difference between the two groups in regard to both efficacy and safety indices (p=0.55 and 0.67, respectively). Both groups had similar residual SE (p=0.72), the proportion of eyes within ±0.5D of SE (p=0.29), and residual refractive astigmatism (p=0.87). Both groups had similar difference vectors, surgically induced astigmatism, and correction index (p=0.82, 0.10, and 0.26, respectively). However, the transepithelial PRK group had lower target-induced astigmatism (TIA; p=0.01), higher magnitude of error (ME; p=0.05), and higher angle of error (AE; p=0.02) than the alcohol-assisted PRK group. Conclusion Transepithelial PRK had similar visual and refractive outcomes as alcohol-assisted PRK. This approach was considered as safe and effective as alcohol-assisted PRK in treating patients with low-to-moderate myopia with or without astigmatism.

Resveratrol increases tear production and ocular pain after corneal abrasion in male, but not female, rats using a photorefractive keratectomy model

Photorefractive keratectomy (PRK) is an alternative to LASIK and can cause intense acute pain that is often not relieved by standard treatments. To assess potential therapeutics for this type of acute pain, appropriate preclinical models are needed. We describe a preclinical corneal abrasion rat model that simulates the initial stages of PRK surgery and demonstrates similar pain and tear dysfunction as seen clinically. We used both behavioral and homeostatic assays to determine the therapeutic potential of resveratrol on pain and tear production. Studies were conducted in male and female Sprague-Dawley rats. Heptanol was applied to one eye and the superficial corneal epithelium was removed, mimicking the abrasion used in PRK. Spontaneous pain was assessed with orbital tightening (OT) scores for 7 days. Topical resveratrol increased OT scores sex-specifically in abraded males, but not females, at 72 h and 1 week after abrasion. Resveratrol increased tear production in abraded males, with no effect in abraded females. There was no correlation between OT score at 1 week and tear production measurements, demonstrating no relationship between spontaneous ocular pain and tear dysfunction in this model. These findings demonstrate the usefulness of our corneal abrasion preclinical PRK model for the assessment of ocular pain therapeutics and indicate that topical resveratrol may not be useful for managing PRK-induced pain.

Transepithelial Photorefractive Keratectomy Compared to Conventional Photorefractive Keratectomy: A Meta-Analysis

This meta-analysis review compares the primary and secondary outcomes of transepithelial photorefractive keratectomy (TPRK) to the conventional photorefractive keratectomy (PRK), in terms of efficacy, predictability, safety, and patient perspectives. A total of 1711 eyes with PRK (811 eyes) and TPRK (900 eyes) from 12 studies were included through bibliographic searches. The main outcomes were efficacy, predictability, and safety parameters, and the secondary outcomes included visual and patient-reported parameters. The effect measures were weighted mean differences with 95% confidence intervals (CI) which were derived from the random-effects model of the meta-analysis to account for possible heterogeneity. TPRK procedure presents a comparable status in the main outcome and a very dominant significance in all the secondary outcomes in this meta-analysis. This study updates the evidence of the accuracy of TPRK procedure for surgical correction of all refractive errors and was deemed safer with less surgical time required and an early healing time.

Corneal Epithelial Removal with a Newly Designed Epithelial Brush

This study aimed to evaluate and compare the effectiveness of a newly developed epithelial removal brush with conventional methods in a rabbit model of corneal epithelial defects. The corneal epithelia of thirty-seven rabbits were removed by three different methods including blades (blade group), newly developed epithelial brushes (Ocu group), and conventional rotating brushes (Amo group). The defect area was measured with light microscopy immediately and at 4, 18, 24, and 50 hours after removal. Corneas were obtained immediately and at 24 and 50 hours and subjected to hematoxylin and eosin (H&E) and immunofluorescence staining using proliferating cell nuclear antigen (PCNA) and phosphorylated heat shock protein 27 (pHSP27) antibodies. The residual stromal surface was observed by scanning electron microscopy (SEM). In the Ocu group, epithelia were significantly recovered at 18, 24, and 50 hours compared with immediately after removal, and in the blade and Amo groups, epithelia were significantly recovered only at 50 hours after epithelial removal. The expression levels of PCNA and pHSP27 did not differ among three groups. There was significantly more inflammatory cell infiltration in the blade group than in the other groups. SEM showed a more regular and uniform residual stromal surface in the Ocu group than in the other groups. The newly developed epithelial brush showed better polishing ability and led to earlier significant epithelial recovery and a more regular and uniform stromal surface than conventional methods in this rabbit model of epithelial defects. Accumulation of clinical data is expected to expand the scope of application of new brushes for laser surface ablation.

Single-Step Transepithelial Photorefractive Keratectomy in Low to Moderate Myopia: A One-Year Follow-Up Study

Aim

To evaluate predictability, safety, efficacy, and visual outcome of StreamLight. ™ (SL.), the newly released single-step transepithelial photorefractive keratectomy platform by Alcon WaveLight™ (WL).

Methods

In this prospective cohort study, photorefractive keratectomy (PRK) was conducted on 500 eyes of 250 patients seeking myopic refractive vision correction. The new single-step transepithelial PRK method was applied, using the SL. platform installed in the WL. Ex 500 excimer laser machine. Patients were followed up to monitor intensity and duration of postoperative pain, as well as speed of epithelial healing in the early post-operative period and visual acuity, postoperative refraction and development of postoperative haze for one year post-operatively.

Results

Average pain duration was 1.5 days, and the mean pain intensity score on a scale of 0–10 was 3.74 + 1.51. Mean postoperative spherical equivalence was 0.01 ± 0.38 D, and the final postoperative uncorrected distance visual acuity (UCDVA) was 20/20 in 98% of eyes included in this study. None of the eyes lost more than one Snellen chart line or developed visually significant postoperative haze during the follow-up period.

Conclusion

The new SL. platform for transepithelial PRK is a safe, accurate platform, offering an easier early post-operative recovery, with no compromise in final visual outcome.

Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use:

https://youtu.be/_lJS9rzTWDk