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Keeping the Cornea Hydrated during CXL: Riboflavin or PBS?

It has been quite the debate. Should surgeons drop riboflavin onto the cornea during the UV irradiation part of a corneal cross-linking (CXL) procedure, or phosphate-buffered saline (PBS)? Simply put: riboflavin or PBS?

Let’s step back. CXL involves the surgeon saturating the structural layer of the cornea, the stroma, with riboflavin. The surgeon then irradiates the stroma with UV light, which causes a photochemical reaction to occur. The reaction between the UV light and riboflavin creates reactive oxygen species, which then immediately react with molecules in the stroma to cross-link them together, which strengthens the cornea. It also consumes the riboflavin, which means as the irradiation proceeds, the UV light reacts with riboflavin that is deeper and deeper in the cornea, thereby strengthening it in those regions.

The reason the surgeon drops a liquid onto the cornea during irradiation is that the patient’s eye is kept open with a speculum, and as the patient cannot blink, fluid evaporates from they eye – so much so that the cornea can actually become slightly thinner during this part of the procedure. But what should the surgeon use to keep the cornea hydrated? Riboflavin or PBS? PBS is simple, inexpensive, and will function perfectly well to keep the cornea hydrated. On the other hand, although it is far more expensive than PBS, riboflavin might be a better option as it can replenish the riboflavin that has been consumed by the UV light. But then, this raises another question: does replenishing riboflavin at the top of the cornea constrict the cross-linking effect to uppermost part of the cornea? Does this affect the strengthening effect?

A team of researchers from the ELZA Institute decided to find out, and they compared the corneal strengthening effect of CXL where riboflavin was used to hydrate the cornea during UV irradiation, with the strengthening effect of CXL when PBS was used for hydration (1). What they found was clear: it doesn’t matter whether the surgeon uses PBS or riboflavin for hydration. The strengthening effect was the same. What this means for clinical practice is also clear. Given PBS is considerably cheaper than riboflavin (and also less messy in the OR!) then choosing PBS to hydrate is a simple and cost-effective choice to make.

 

Corneal strength measuring apparatus in Prof. Hafezi’s laboratory at the Ocular Cell Biology group at the Center for Applied Biotechnology and Molecular Medicine at the University of Zurich.

 

 

Reference

  1. Abdshahzadeh H, Abrishamchi R, Aydemir ME, et al. Repeated application of riboflavin during corneal cross-linking does not improve the biomechanical stiffening effect ex vivo. Experimental Eye Research. 2022;224:109267. doi:10.1016/j.exer.2022.109267

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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
Based on 109 reviews
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