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Wavefront-guided transPRK for improving visual quality

Prerequisite: stable cornea

Unlike PACE, wavefront-guided transPRK involves the removal of small amounts of stromal tissue. Since the stroma forms the cornea’s structural foundation and is inherently thinner and more fragile in corneas with keratoconus or other corneal ectasias than in healthy corneas, it is crucial to ensure this procedure is performed only on corneas that are biomechanically sufficiently robust.

Accordingly, corneas must be cross-linked before considering this procedure (either with a regular CXL procedure or PACE customized cross-linking). After the corneal shape has stabilized (which takes up to 12 months after the procedure), we can then assess whether the cornea is suitable for lasering. We will comprehensively assess the cornea’s shape and biomechanical strength to ensure it is safe to proceed with the laser treatment.

In some cases, it is possible to combine CXL and wavefront-guided transPRK.

What wavefront-guided transPRK for keratoconus achieves

Wavefront-guided PRK for keratoconus can significantly improve patients’ visual quality. The excimer laser platform ELZA uses, the SCHWIND AMARIS, is unique in its ability to selectively target higher-order wavefront errors (HOAs) for correction. These HOAs arise because the cone makes the surfaces of the cornea increasingly irregular. HOAs, which cannot be corrected by spectacles, cause the hallmark keratoconus visual disturbances of ghosting, blurring, double or even triple vision, and issues with glare and starbursts at night. In keratoconus, wavefront-guided transPRK is used solely to reduce these aberrations. This minimizes the tissue removal by the laser and can result in a dramatic improvement in visual quality.

Wavefront-guided transPRK and CXL – simultaneously or sequentially?

We opt for laser treatment only after cross-linking. The rationale behind this approach is that, despite the high success rate of cross-linking, it does not guarantee 100% efficacy: in 3 to 7% of cases, keratoconus may still progress even after comprehensive cross-linking. Additionally, though exceedingly rare (0.5%), some corneas may undergo significant flattening post-cross-linking. Therefore, the safest approach is to delay laser procedures until the corneas have stabilized.

Precise lasering

Until recently, a critical piece of information was missing for accurately lasering a cornea post-cross-linking: the exact amount of corneal tissue removed by an excimer laser pulse following CXL. Is it the same amount as in a non-cross-linked cornea? Or 20% less? Perhaps 40% more?

Lacking knowledge of the precise ablation rate leads to inaccuracy in results.

Our research

Our group conducted an extensive study to determine the ablation rate in corneas post-CXL, with findings published in the American “Journal of Refractive Surgery”: https://pubmed.ncbi.nlm.nih.gov/25250420/

We discovered that in a cornea treated with CXL, each excimer laser pulse removes 12% less tissue compared to a cornea without CXL. This insight significantly enhances the precision of our treatments.

Our results

Beyond the improvement in visual acuity, it is primarily the enhancement in image quality that benefits our patients. Unlike visual acuity, “image quality” as a concept lacks a simple metric in ophthalmology.

Thus, improving visual acuity is just one aspect of the overall enhancement. Equally crucial is that an increase in visual acuity by over 50% can augment three-dimensional vision (depth perception), offering a comprehensive improvement in visual experience.

48-year-old man.
Before and 20 months after laser treatment.
Before and 3 years after laser treatment.
Before and 6 months after laser treatment.
Before and 4 months after laser treatment.
Before and 14 months after laser treatment.
Before and 10 months after laser treatment.
Before and 3 months after laser treatment.
Before
After

39-year-old man, 6 months after laser treatment.

Vision increased with glasses from 20% to 50%.

Before
After

39-year-old man, 6 months after laser treatment.

Vision increased with glasses from 10% to 40%.

Before
After

35-year-old man, 1 year after laser treatment.

Vision increased with glasses from 20% to 60%.

Before
After

35-year-old man, 1 year after laser treatment.

Vision increased with glasses from 20% to 60%.

Before
After

41-year-old man, 3 months after laser treatment.

Eyesight increased from 60% to 80% with glasses.

Before
After

33 year old woman, 2 years after laser treatment.

Eyesight increased from 50% to 80% with glasses.

Before
After

51 year old woman, 2 years after laser treatment.

Eyesight increases with glasses from 50% to 125%.

Before
After

40-year-old woman, 1 year after laser treatment.

Eyesight increased from 40% to 50% with glasses.

Before
After

28-year-old man, 3 months after laser treatment.

Eyesight increases with glasses from 40% to 60%.

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Augeninstitut ELZA
4.8
Based on 109 reviews
powered by Google
mike
mike
09:02 04 Jan 23
Overall as a 50 year old, who wanted to continue to avoid wearing glasses and/or contact lenses, my goal was 100%... achieved with ELZA and Dr. Hafezi. I greatly appreciated the overall approach by Dr. Hafezi and his friendly and competent team in reviewing my vision at the start and following a comprehensive eye exam- the explanations of my options. For me I chose PRK in one eye for a monovision solution to correct short sightedness which was becoming more prevalent in night driving and sports such as skiing and cycling. PRK heals slowly but the outcome is worth the wait- and the cost- you use your eyes every waking moment- and for me I cannot see any reason not to pursue better vision with the ELZA team! A great quality of life enhancement!read more
Zuzana Fecko
Zuzana Fecko
21:48 31 Oct 22
Thank you so much, Dr. Torres and prof. Hafezi. 26 years I was only “dreaming” about the eye surgery due to possible... complications. I was worried ..Thank you for encouraging me to make a decision and thank you for your professionalism, explanations and great work!I wish you all the best, lots of success and only happy patients!read more
Serena Fazio
Serena Fazio
11:15 06 Mar 22
I have been to the ELZA clinic to have surgery for my miopy, as my eyes were rejecting the contacts and I was tired of... wearing glasses. From the first preliminary visit, to the actual surgery and post-surgery care Dr. Hafezi and all his collaborators have been extremely professional, considerate and helpful. All the steps of the (very short!) surgery were thoroughly explained to me in order to be as calm as possible, together with the medication plan and precautions to be aware of so that my eyes could heal in the best way possible. By following their exact instructions, the healing process has been very successful and smooth, and after about one week I was able to see perfectly. I absolutely recommend this team and their expertise!read more
Robin A
Robin A
11:43 16 Feb 22
Top experts and professional team. Highly recommended
Thunder Shiviah
Thunder Shiviah
14:05 23 Nov 21
After some research on local options I decided to go with ELZA since it stood out as the best. The operation and the... post-operation recovery went extremely smooth (something I was worried about with PRK). Now my vision is much better than I had hoped and I have no side effects such as dry eye or night vision problems. Thank you!read more
Thomas S.
Thomas S.
09:37 07 Jul 21
My left eye had to be operated on because of a cataract. As I had an Artiflex lens implanted a few years ago, it had to... be removed first before a modern lens could be implanted to correct the cataract. Prof. Hafezi treated me in an very competent and friendly manner. I am very happy with the result.read more
Selma A. Rahim
Selma A. Rahim
19:45 02 Jul 21
Dr. Hafezi.. the KING OF CXL🤴
Gianluca Ricci
Gianluca Ricci
12:46 10 Apr 21
Great team and service!
rehaneyecare
rehaneyecare
05:36 08 Apr 21
Excellent surgeon
Steven H.A
Steven H.A
16:13 11 Jan 21
Prof. F. Hafezi s expertise is enormous and he has a very pleasant and calm nature which gives the patient... security.Thank youread more
Online Commande
Online Commande
09:19 05 Dec 20
Totally creepy, very arrogant Prof.He just want your money.It may explain, why this Prof. is not in the center of the... city of Zürich and why he has been thrown away from University of Geneva.read more
Elena Churilova
Elena Churilova
10:06 17 Nov 20
At the moment, 3 months have passed since the moment I made laser vision correction in this clinic. and I can say that... I am happy that I chose this particular clinic and Prof. F. Hafezi. The entire staff of the clinic is very friendly, treats patients with sympathy and patience if they are nervous before surgery (my big gratitude to Aida Alili for all support and patience). The doctor Hafezi and other doctors of the clinic are very professional and ready to explain to you as many times as you need. I can only recommend!read more
Michele Aggiato
Michele Aggiato
18:17 10 Jan 20
The day I had Prof Hafezi checking my keratoconus I knew I was finally in the right place after years of searching for... a good ophthalmologist. Prof Hafezi recommended a surgery due to a drastic degeneration of my cornea. The surgery was performed by himself with the assistance of Dr Rodriguez, one more collaborator of Prof Hafezi’s team who got my full trust.read more
Ashley Faulkes
Ashley Faulkes
15:30 21 Mar 16
Professor Hafezi and the team at the ELZA Institute have done an amazing job of creating a first class eye clinic, with... cutting edge technology and support. I went there for a dry eye issue and other issues with my prescription, and they were easily able to help me and put me on the road to better vision! High recommend them to anyone in the Zurich/Aargau area.read more
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Augeninstitut ELZA
4.8
Based on 109 reviews
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