Trends in indications and techniques of corneal Transplantation from 2010 through 2024 at a tertiary referral centre in Rabat, Morocco

The Clear Window and the Fading Clouds

Imagine your eye as a high-definition camera. For the camera to take a sharp picture, the front glass lens—the cornea—must be perfectly clear and smooth. Sometimes, that glass gets scratched, scarred, or starts to bulge like a warped balloon. When the damage is too deep to fix with drops or laser surgery, doctors have to swap the broken glass for a new one. This is called a corneal transplant. It's like replacing a shattered windshield with a pristine new one so you can see the road again.

For decades, the standard way to do this was to swap the entire thickness of the glass, a bit like replacing a whole pane of window glass. But recently, doctors have learned they can be more like a skilled glassblower, swapping only the specific layer that is broken. If the back layer is cloudy, they swap just the back; if the front is warped, they swap just the front. This paper looks at how these "glass-swap" techniques have changed over 15 years at a major hospital in Rabat, Morocco. It's a story about how the reasons people need new windows are shifting, and how the tools doctors use to fix them are getting more precise and less invasive.

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The Story of the 3,097 New Windows

Between 2010 and 2024, a team of doctors at Cheikh Zaid University Hospital in Rabat, Morocco, performed corneal transplants on 3,097 patients. All the new "glass" (donor corneas) used in these surgeries came from eye banks in the United States, shipped in to Morocco. The researchers looked back at the records of every single one of these patients to see what was wrong with their eyes, how old they were, and which surgical method the doctors chose.

Who needed the new windows?
The patients were a mix of ages, ranging from 1 year old to 94 years old, with the "average" patient being 37 years old. However, the group was surprisingly young. The biggest chunk of patients (42.3%) were between 18 and 40 years old. This is very different from what happens in places like the US or Europe, where most people needing these surgeries are older. In Morocco, the main culprit was a condition called keratoconus. Think of keratoconus as a weak spot in the cornea that slowly bulges outward, turning a smooth lens into a bumpy, distorted one. This condition accounted for nearly half (47.56%) of all the surgeries.

The second most common reason was bullous keratopathy, which happens when the inner layer of the cornea gets damaged (often after other eye surgeries like cataract removal) and the eye fills with fluid, making it look like a cloudy, swollen balloon. This made up about 20% of the cases. The third group had scars from old infections or injuries, accounting for about 11%.

How the reasons changed over time
The researchers noticed a fascinating shift in the "why" behind the surgeries. In the early years of the study (around 2014 and 2015), keratoconus was the undisputed king, making up over 60% of all cases. But as time went on, its share started to shrink, dropping to about 37% by 2024. Why? The authors suggest that doctors are getting better at spotting the bulging early and using a treatment called "cross-linking" to strengthen the cornea before it gets bad enough to need a transplant.

At the same time, the need for surgery due to fluid-filled, swollen eyes (bullous keratopathy) was climbing steadily. It started at about 10% in 2010 and grew to nearly 27% by 2024. This mirrors what is happening globally: as people live longer and have more cataract surgeries, more of them end up needing help with the inner layer of their cornea later in life.

How the surgery changed
The way doctors performed the transplants also evolved, moving from a "brute force" approach to a "surgical precision" approach.

• The Old Way (PKP): For a long time, the standard was Penetrating Keratoplasty (PKP). This is like taking a hammer and chisel to the whole window and replacing the entire pane of glass. In 2010, this was used in 97% of cases. By 2024, that number had dropped to 57%.
• The New Way (Lamellar): Doctors started using techniques that only replace the damaged layer.
  • DALK: For the bulging corneas (keratoconus), they began using Deep Anterior Lamellar Keratoplasty. This is like swapping only the front, warped part of the glass while keeping the healthy back layer intact. This method grew to become the second most common surgery, used in about 21% of all cases.
  • DMEK: For the fluid-filled, swollen eyes, they started using Descemet Membrane Endothelial Keratoplasty. This is like swapping just the very thin, innermost film of the glass. This technique was introduced in 2018 and grew rapidly, reaching 23% of all surgeries by 2024.

The "Pandemic Pause"
The study also spotted a dip in surgeries in 2020 and 2021. The number of transplants dropped sharply during these years. The paper explains this wasn't because people didn't need the surgery; it was because the supply chain broke. Since Morocco relies entirely on imported corneas, the global chaos of the pandemic stopped the shipments. This highlighted a major weakness: without a local eye bank to store and supply corneas, the program is vulnerable to global disruptions.

What the paper rules out
The authors are clear that this study is about what happened at their specific hospital, not about testing a new drug or a new theory. They do not claim to have invented these techniques; they simply tracked how their hospital adopted them. They also note that while they saw a drop in keratoconus surgeries, they cannot prove exactly why with this data alone, though they strongly suspect it's due to better early detection and the use of cross-linking.

The Bottom Line
Over 15 years, the hospital in Rabat transformed. They went from mostly doing "whole-window" replacements for young people with bulging corneas to a more balanced mix of surgeries. They are now using more precise, layer-by-layer techniques that are better for the patient's recovery. While keratoconus is still the top reason for surgery in Morocco, the rise of fluid-related issues and the shift toward modern, less invasive surgery shows that Moroccan eye care is catching up with global trends. The only thing holding them back from being fully independent is the lack of a local eye bank to keep the supply of new "glass" steady, no matter what happens in the rest of the world.