Farhad Hafezi was interviewed by Eyetube on the K-MAP keratoconus prevalence study at ESCRS 2018.
Hi, my name is Prof. Farhad Hafezi, I’m the chief medical director of the ELZA Institute in Dietikon, Zurich as well as a professor of ophthalmology at the University of Geneva, Switzerland and the USC Roski Eye Institute, Los Angeles.
The topic of my talk is The Light For Sight KMAP global prevalence of keratoconus study. Now, this is a long name and let me break down the title. First of all, keratoconus, if you open up a textbook, is a rare disease. If you look at the classification you will see that the prevalence is set to 1 in 2000 people in the normal population. And we believe that the real prevalence of the disease is way higher than that.
Why does it play a role?
It does play a role because 20 years ago we had no possibility to treat a patient once the disease is detected but now with modern corneal cross-linking technology we can treat young patients with keratoconus. So detecting the disease at an early stage is key and detecting the disease also means knowing how rare or even how not rare the disease is. And this is what we put the focus on.
Again, you open a textbook and you read 1 in 2000 patients and this all boils down to a 1986 paper published by Kennedy and colleagues in The American Journal stating that keratoconus is rare. The data that has been analyzed for this 1986 paper that we all still cite in the textbooks has been collected in Minnesota between the 1930s and 1980s. So you can imagine the standard of technology that was used at that time and the sensitivity of the methods to detect keratoconus. Today we have much more modern technology and we also know that geographically there are large variations of disease prevalence.
So what we have started is a global study and it all started with a pilot that we did in Riyadh, Saudi Arabia. The pilot was published a few months ago in The British Journal and we had amazing numbers. We screened 1044 eyes and then had all these eyes – it was screened with a Scheimpflug imaging system – and we had all these eyes then evaluated by two independent corneal surgeons. And in all but 9 eyes they had perfect congruence in defining the disease, so stating whether or not this person carries keratoconus or not. And in only 9 cases there was discrepancy.
If you then look at the overall prevalence we published we were at almost 5% of the normal population aged 6-21 years. So the prevalence we found in this particular area of the world was almost 100 times higher than what was reported by Kennedy in 1986. And this stimulated our foundation The Light For Sound Foundation to start a global prevalence study. And with this study we’ll now look at the global prevalence of keratoconus on four continents.
The study sites were recruited among The Light For Sight centers. We are represented in 42 countries on 5 continents right now and out of these 42 centers, 11 centers are enrolled in the studies, 5 already have positive IRB approval and will start collecting data in the next months. Our aim is to collect 15 000 to 20 000 eyes to get a better idea about the global distribution of prevalence and also it might shine a light on the difference between environmental factors and genetics.
Just think about the possibilities of looking at a cohort of let’s say Chinese patients in mainland China and the Chinese population in San Francisco. Similar genetic backgrounds totally different environments. So we are very excited to hopefully present new, large data in the next 24 months.