The short version: epi-on corneal cross-linking strengthens a cornea weakened by keratoconus without scraping off its outer layer, the epithelium. The first FDA-approved epi-on treatment, Epioxa, was approved on October 20, 2025, for patients aged 13 and older, and became available in early 2026. Because there is no surface wound, most patients are back to normal activities within days rather than the one to four weeks typical after traditional epi-off cross-linking. Like all cross-linking, it is designed to stop keratoconus from getting worse, not to reverse vision already lost, so the earlier it is done, the more vision it protects. At Berg-Feinfield we offer both epi-on and epi-off cross-linking and choose based on your corneas, at offices across Los Angeles, the San Fernando Valley, the San Gabriel Valley, and Santa Clarita.
I have treated keratoconus for more than 30 years and was among the first surgeons in Southern California to offer FDA-approved corneal cross-linking. For most of that time, recommending cross-linking has meant explaining a trade-off. Cross-linking works. It is the only treatment that stops keratoconus from progressing. But the traditional procedure begins by removing the epithelium, the thin protective skin on the front of the cornea, and the days that follow are uncomfortable enough that some people put the treatment off. With keratoconus, putting it off has a cost.
Epi-on cross-linking is the most meaningful change in that conversation that I have seen. This is what I tell patients about it.
Keratoconus in plain terms
The cornea is the clear dome at the front of your eye. It is built from tightly organized collagen fibers, and its job is to focus light precisely onto the retina. In keratoconus, those fibers weaken. The cornea gradually thins and bulges forward into an irregular cone, which scatters light instead of focusing it.
Keratoconus usually begins in the late teens or early twenties and can progress over 10 to 20 years. The signs are easy to mistake for an ordinary prescription change:
- Glasses or contact lens prescriptions that change often, usually with rising astigmatism
- Blurred or distorted vision, sometimes described as ghosting or double images
- Glare, light sensitivity, and halos or starbursts that make night driving hard
- Eye strain and headaches from working harder to see
Family history matters: roughly one in ten people with keratoconus has a relative with the condition. Chronic eye rubbing, often tied to allergies, is a major and preventable contributor. The diagnosis is confirmed with corneal topography and tomography, which map the shape and thickness of the cornea and can detect steepening long before vision is badly affected.
Why cross-linking, and why timing matters
Corneal cross-linking uses riboflavin, vitamin B2, and a controlled dose of ultraviolet-A light to create new bonds between the collagen fibers. The cornea becomes stiffer and more stable, and progression stops in the large majority of treated eyes. In some patients the cornea even flattens slightly over time.
What cross-linking does not do is undo damage that has already happened. That single fact drives my thinking about timing. A cornea treated early, while vision is still good, stays close to where it was. A cornea treated late may still be stabilized, but the patient may need specialty contact lenses to see well, and in advanced cases may face a corneal transplant. Cross-linking often avoids the need for a transplant altogether, and earlier treatment gives it the best chance to.
What changed in October 2025
On October 20, 2025, the FDA approved Epioxa, from Glaukos, the first approved cross-linking treatment that does not require removing the epithelium. Its approval followed two Phase 3 clinical trials involving more than 400 patients, and it became commercially available in early 2026 for adults and adolescents aged 13 and older with keratoconus. Berg-Feinfield was the first practice in Los Angeles to offer it.
The challenge epi-on treatment had to solve is that an intact epithelium makes it harder for riboflavin to reach the deeper cornea and limits the oxygen the cross-linking reaction needs. Epioxa addresses both: a specially formulated riboflavin designed to pass through the intact surface, and supplemental oxygen delivered during the light treatment.
How epi-on cross-linking works at our practice
The procedure is done in the office under numbing drops. The full treatment usually takes about 60 to 90 minutes:
- Evaluation first. Corneal tomography, pachymetry to measure thickness, and a review of your topography over time to confirm progression and decide whether epi-on or epi-off is the better choice for your eyes.
- Riboflavin drops. The drops are applied in sequence and work through the intact surface to saturate the cornea. No scraping and no wound.
- Oxygen goggles. You wear comfortable goggles that bathe the eye in oxygen, which is what allows the reaction to work with the epithelium in place.
- UV-A light. A calibrated ultraviolet-A light activates the riboflavin and forms the new collagen bonds.
- Home the same day. No patch and no hospital stay. Most patients return to school, work, and normal activities within days.
Epi-on vs. epi-off: an honest comparison
We offer both procedures, and I do not think either one is right for everyone. Here is how they compare:
| Epi-on (Epioxa) | Epi-off (traditional) | |
|---|---|---|
| Epithelium | Left intact throughout | Removed before treatment |
| Discomfort | Minimal; no surface wound | Moderate for several days while the surface heals |
| Recovery | Days to one to two weeks | One to four weeks for full healing |
| Infection and haze risk | Lower, with the surface intact | Higher while the surface is open; haze possible |
| FDA indication | Keratoconus, ages 13 and older | Progressive keratoconus and post-LASIK ectasia |
| Long-term data | Phase 3 trials; still accumulating | Extensive real-world experience over many years |
The right choice depends on disease stage, corneal thickness, and your individual profile, and is made at your evaluation.
Epi-off cross-linking remains the better choice in some situations: more advanced keratoconus, certain corneal thickness measurements, and corneal weakening after previous refractive surgery, called ectasia. Having both available means the treatment is matched to the cornea rather than the other way around. For a deeper look at both options, see our epi-on corneal cross-linking page.
Who is a good candidate for epi-on cross-linking
- Documented progression, confirmed by changes in corneal topography over time.
- Enough corneal thickness to support the procedure safely.
- Age 13 or older, particularly teenagers and young adults whose keratoconus is still active.
- Early-to-moderate disease, where epi-on treatment performs best.
- Patients who have delayed epi-off cross-linking because of the recovery.
If your keratoconus has already stabilized, which often happens by a patient’s 40s or 50s, you may not need cross-linking at all. In that case, our focus shifts to getting you the clearest vision possible with the right lenses.
A word to parents
Keratoconus is most often diagnosed in the teenage years, and it tends to progress fastest in young patients. The younger the diagnosis, the more years of vision are at stake. Until now, the recovery from epi-off cross-linking meant asking a high school student or a college athlete to give up a week or more of classes, practice, and screens. That is a real barrier, and I understand why families hesitated.
With epi-on treatment approved from age 13, that barrier is much lower. If an optometrist has told you your child’s prescription keeps changing, or has flagged your child as a keratoconus suspect, I would encourage a timely evaluation. We will give you an honest answer, even if that answer is to keep monitoring for now.
Keratoconus, LASIK, and seeing well afterward
Keratoconus is one of the reasons we screen every LASIK candidate with corneal topography. LASIK removes corneal tissue, and in an eye with early or undiagnosed keratoconus that can make the cornea weaker. It is one of the patterns I describe in what 50,000 LASIK procedures have taught me: the best outcomes start with knowing who should not have a given procedure. Patients with keratoconus are not LASIK candidates, but they are not out of options either; our guide to which vision correction procedure is right for you explains the alternatives.
Cross-linking protects the vision you have; it is not designed to correct it the way LASIK does. Once the cornea is stable, specialty contact lenses, including scleral, hybrid, and rigid gas-permeable lenses, usually provide the sharpest vision. Most of our keratoconus patients continue that part of their care with their own optometrist or a specialty-lens practice we partner with, and we coordinate closely with them. Optometrists can learn about referring on our partnering optometrists page.
Where to be seen in Los Angeles
Epioxa is offered across our five Los Angeles-area offices. I see keratoconus patients at our Burbank, Sherman Oaks, and Beverly Hills offices, and my colleague Dr. Bonnie Sklar, who completed her cornea fellowship at Duke University Eye Center after residency at Wills Eye Hospital, sees keratoconus patients at Burbank and Sherman Oaks.
- Westside, Beverly Hills, West Hollywood, Santa Monica, and Century City: our Beverly Hills office at 462 N. Linden Drive.
- Studio City, Encino, Van Nuys, and the central San Fernando Valley: Sherman Oaks, at 13320 Riverside Drive.
- Burbank, Glendale, North Hollywood, Toluca Lake, and Pasadena: Burbank, at 2625 W. Alameda Avenue.
- Arcadia and the San Gabriel Valley: our Arcadia office on W. Duarte Road.
- Valencia, Santa Clarita, and Stevenson Ranch: our Valencia office on Tourney Road.
Insurance coverage for epi-on cross-linking is still evolving because the treatment is so new. Our team verifies your benefits and gives you any out-of-pocket cost in writing before treatment, and financing through CareCredit and other programs is available. You can also review our insurance information.
Why I care about this one
Much of my career has been spent helping people see without glasses. Keratoconus is different. The goal is not freedom from glasses; it is protecting a young person’s vision for the next 50 or 60 years. Cross-linking gave us the tool to do that. Epi-on cross-linking removes the main reason people waited to use it. If you or your child has keratoconus, or a prescription that will not stop changing, come in and let us map your corneas. That map is where every good decision about keratoconus begins.
Alan M. Berg, MD
Board-Certified Ophthalmologist & Cornea and Refractive Surgeon
Dr. Berg is Berg-Feinfield’s primary surgeon for corneal cross-linking, with more than 30 years of keratoconus and corneal surgery experience. He was among the first in Southern California to offer FDA-approved cross-linking, was one of 50 U.S. surgeons selected for the Implantable Collamer Lens clinical trials, and teaches ophthalmology residents at USC. He has performed more than 50,000 LASIK procedures.