Effectiveness of Trans-PRK: Scientific Articles in Peer-Reviewed Journals

Study published at the SFO 2011: Standard PKR versus transepihelial PKR (Trans PKR): anatomical and functional results.

(by V. Kocaba-Salles and Professor C. Burillon of the Lyon Civil Hospitals)

Conclusion of the study:

TransPKR, a new, totally non-contact technique, therefore makes it possible to reduce pre- and post-operative pain and the number of delayed healings, while achieving refractive results similar to those of standard PRK.

Introduction

Prospective study comparing the anatomical and functional results of standard PRK with transepihelial PRK, a new totally non-contact technique. Evaluation of the refractive results of transepihelial PRK. Comparison of pre- and post-operative pain between the two techniques. Comparison of post-operative complications.

Equipment and methods

60 patients were included, i.e. 120 eyes. 60 eyes were treated with standard PRK (two-stage treatment: mechanical removal of the corneal epithelium after application of alcohol, followed by refractive treatment with Excimer, Amaris or Schwind laser), 60 with transepihelial PRK (one-stage non-contact treatment with Excimer laser), divided into two groups according to the treatment modality. Criteria studied: age, sex, pre- and post-operative refraction, post-operative complications: delayed healing, haze, over- or under-correction, decentring of the treated area, pre- and post-operative pain on days 1, 2 and 3 assessed by the Visual Analogue Scale rated between 0 and 10 (0: no pain, 10: unbearable pain).

Results

The two groups were comparable in terms of age, sex ratio, and pre- and post-operative refraction. There was no significant difference in terms of over- or under-correction, haze or decentring of the treated area. However, there was a significant difference in the number of cases of delayed healing, with five in the PRK group and none in the Trans-PCR group.

Discussion

Trans-PCR is just as effective as standard PRK for surface refractive treatment. However, this technique not only eliminates pre-operative pain but also significantly reduces post-operative pain, as the epithelial ablation is strictly identical to the optical zone treated (on average 6.5mm in diameter). The ulcer created is therefore smaller in size, which reduces healing time. This may also explain the absence of delayed healing in the Trans PKR group.

Study carried out by the Haug Lasik Centrum in Pforzheim, Germany:

Results at one month and 3 months after Trans PK

Conclusion :

Our results with Trans-PRK are in line with previously published results versus PRK / LASEK / EpiLASIK.
The main advantages are shorter recovery time and one-step treatment with significantly reduced post-operative risks.

This technique allows less abrasion of the epithelium and therefore faster re-epithelialisation, with less discomfort and pain and less risk of infection due to rapid epithelial healing. In all patients, the epithelium had healed by the 3rd postoperative day.

See the full study:

http://trans-pkr.fr/wp-content/uploads/2014/03/Haug-TransPRK.pdf

Clinical ophthalmology
Comparison of single-stage transepithelial laser ablation (ASLA) to alcohol-assisted photorefractive keratectomy
.

Ioannis M Aslanides1, Sara Padroni1, Samuel Arba Mosquera2, Antonis Ioannides1, Achyut Mukherjee1,
1Emmetropia Mediterranean Eye Institute, Heraklion, Crete, Greece;
2Schwind eye-tech-solutions GmbH, Kleinostheim, Germany

Goal:

To evaluate post-operative pain, corneal epithelial healing, corneal haze development, refractive outcomes, and corneal aberrations in a one-step treatment, modified photoepihelial keratectomy (PRK), called All-Surface Laser Ablation (ASLA), compared to conventional PRK with alcohol epithelial removal.

Equipment and methods

Sixty eyes of 30 myopic patients were prospectively recruited. Patients underwent PRK with conventional alcohol abrasion in one eye (control group) and modified ASLA transepihelial PRK in the 2nd group (30 eyes in each treatment arm) . Primary endpoints were post-operative pain and haze scores at 1 day, 3 days, 1 week, 1 month, 3 months, 6 months and 12 months. Secondary endpoints were visual acuity at 1, 3, 6 and 12 months, corneal aberrations at 3, 6 and 12 months, and late onset and haze.

The refraction predictability, safety and efficacy of the two methods were examined.

Results : The mean age of the cohort was 29 years (standard deviation [ SD ] : 9 ; range : 18-46), and the mean spherical equivalent refractive error was -4.18 dioptres ( SD: 1.9).

At 3 days after surgery, the mean pain score was 64% lower in the ASLA group (trans PKR) (P, 0.0005 ).

At this stage, 96% of ASLA/transPKR eyes had no epithelial lesions, while 43% in the alcohol group had not achieved complete healing of the epithelium.

The level of disorder was consistently lower in the ASLA/transPKR group at all controls from 1 to 6 months.

Conclusion :

This study shows that the ASLA/transPKR technique may have a future role in refractive surgery, as it offers faster epithelial healing, lower pain scores, and much less haze formation.

See the pdf of the full article:

http://trans-pkr.fr/wp-content/uploads/2014/03/2012-06-Clinical-Opht_TransPRK-ASLA_Aslanides-et-al.pdf

Trans PKR: study carried out on clinical results by Clinical results

Ali Fadlallah, MD, Daoud Fahed, MD, Khalil Khalil, MD, Ibrahim Dunia, MD…
And published in the Journal Cataract Refractive Surgery 2011

Objective: to evaluate the efficacy, safety and comfort of Trans PKR using the Amaris laser platform.
Setting: ophthalmic Consultants of Beirut , Jal -El- Dib , Metn , Lebanon .

Method: Myopic eyes with or without astigmatism were treated with trans-PCR (group study) and compared with the eyes of a control group treated with conventional PRK, during which the epithelium was removed with alcohol.

Post-operative pain, epithelial healing, visual acuity, manifest refraction and haze were analysed.

Results: The mean subjective post-operative pain score (out of 10, indicating worst pain) at 48 hours was 2.0 in the transPKR study group (50 eyes) and 4.5 in the conventional PKR control group (50 eyes) (PZ.02).

The mean time to epithelial healing was 2.5 days G0.6 (SD) and 3.7G0.8 days, respectively (PZ.01).

At 1 week, UDVA was significantly better in the control group, but at 3 months, there was no statistically significant difference in UDVA, corrected visual acuity distance, or manifest refraction between the groups.

Haze was significantly lower in the Trans PKR study group (P < 0.01).

CONCLUSION: Trans PKR for mild to moderate myopia with or without astigmatism was found to be safer and easier to perform than conventional PRK, and patients had less pain, less post-operative discomfort, less haze, and a faster recovery time.

The visual acuity results with the two techniques were comparable.
Journal Cataract Refractive Surgery 2011; - : - Q 2011 ASCRS and ESCRS

See the PDF of the full article:

http://trans-pkr.fr/wp-content/uploads/2014/03/2011-Aug-JCRS-Transepithelial-TransPRK-Amaris-Fahed.pdf

Brochure on Trans-PKR by SCHWIND AMARIS

Trans PKR: non-contact technique with Schwind Amaris :

http://trans-pkr.fr/wp-content/uploads/2014/03/TransPRK_Flyer_2011-E.pdf

VIDEO: WHAT IS TRANS-PKR?

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