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PACK cross-linking in keratitis

UV light and Vitamin B₂

The use of ultraviolet light and vitamin B₂ (riboflavin) to sterilize surfaces and solutions is not new. This combination has been used for decades in medicine and the chemical industry. For example, the number of microbes in large Olympic swimming pools is often reduced with vitamin B₂ and sunlight. In addition, the technology has been used for years to reduce the number of bacteria in blood transfusions. In addition, there was also the SODIS (Solar Disinfection) technology developed by ETH Zurich to reduce the burden of drinking water with microbes. Here, vitamin B₂ is added to water in PET bottles and exposed to direct sunlight for several hours. After this treatment, bacteria, fungi and even viruses in the bottle are killed.

UV light and vitamin B₂ are the components of the cross-linking of the cornea, which has been used since 2002 for the treatment of keratoconus and which we have co-developed significantly. The question then arose as to whether the method could possibly also be used for corneal infections.

Pioneered in Zurich: cross-linking for corneal infections

In 2006 and 2007, our group in Zurich treated the world’s first patients with this new method. Only patients who show no improvement after treatment with antibiotics were treated. The success was promising and the beginning of a branch of research that is becoming increasingly important.

   

PACK-Cross-Linking (PACK-CXL)

At the International Cross-Linking Congress in Zurich in 2014, Farhad and Nikki Hafezi proposed a new term to better describe cross-linking for infections: PACK-CXL (photoactivated chromophore for infectious keratitis). The proposal was accepted and has since been used for this new treatment method.

Before PACK-CXL

After PACK-CXL

Reasons to use PACK-CXL

There are a number of reasons to use this new method:

  • Mixed infections:
    in many countries of the world, the corneal infections are not bacterial but mixed, that is caused by bacteria and fungi. Antibiotics alone do not help here. PACK cross-linking kills bacteria and fungi.
  • Therapeutic and diagnostic dilemma: at the beginning of an infection it is sometimes very difficult to assess whether the infection is caused by bacteria or fungi. Accordingly, it is difficult to select the appropriate therapy. PACK cross-linking simplifies the approach by simultaneously killing bacteria and fungi.
  • Financial burden: in many countries of the world, the corneal infection can not be successfully treated for financial reasons. The costs are less due to the medication than through the many doctor visits that are necessary. One-time PACK cross-linking reduces the total number of visits required by the doctor.

How does PACK-CXL work?

It works in three different ways:

1. It prevents microorganisms from multiplying by deactivating the genetic material,
2. It kills microorganisms directly by a very high oxidative stress and
3. It increases the resistance of the tissue to the inflammatory digestion.

1 Intercalation with DNA = stops replication

2 Oxidative stress

3 Increased resistance to digestion

PACK-CXL clinical trial

A large, international, multicenter phase III trial that involved patients with infectious keratitis that was thought to be caused by bacteria, fungi or a mixture of the two was published in 2021. Patients were treated with either PACK-CXL alone, or standard antimicrobial therapy. “Treatment success” was defined as the complete resolution of any sign of infection- and time to re-epithelialzation (where the cells at the top of the cornea have regrown over the site of infection). The result: both treatments were about 90% successful, and there was no difference in time to re-epithelialisation between treatment groups.

Click here to read the manuscript.

PACK-CXL videos

PACK-CXL Posts

The article by Lu et al. reports an in vitro study, conducted to determine whether high-fluence PACK-CXL can be accelerated while still maintaining its antibacterial efficacy. The study found that high-fluence PACK-CXL did indeed decrease the bacterial concentration of several clinically significant bacterial strains, including S. aureus, P. aeruginosa, and S. epidermidis. These strains are commonly implicated in bacterial keratitis and contact lens-associated keratitis. Furthermore, the authors found that higher total fluence PACK-CXL protocols led to a corresponding increase in bacterial killing ratio (BKR).
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Augeninstitut ELZA
4.8
Based on 109 reviews
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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
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