Keratoconus usually changes slowly, over years. Symptoms usually appear in the late teens or early 20s, and the condition may progress for 10 to 20 years and then slow. MedlinePlus Genetics describes the same arc: the eye changes typically begin in adolescence and slowly worsen until mid-adulthood, when the shape of the cornea stays stable. Those are typical patterns, and each eye may change at its own pace. The way to know your own pace is to compare corneal maps over time, and documented progression is the signal to consider corneal cross-linking, which halts or slows it.
Key takeaways
- Keratoconus usually worsens gradually, with symptoms appearing in the late teens or early 20s, and it may progress for 10 to 20 years before slowing.
- Each eye may change at its own pace, so both corneas need regular maps, even if only one has been diagnosed.
- Comparing corneal maps over time shows your own pace, and when they document progression, it's time to consider cross-linking, which halts or slows it.
- Sudden haze or clouding in an eye with keratoconus, or severe eye pain, means calling us right away for a same-day exam, or an emergency room when we're closed.
01
At what age does keratoconus stop progressing?
Usually by mid-adulthood. MedlinePlus Genetics says the changes typically worsen until mid-adulthood, when the shape of the cornea remains stable, and the AOA says keratoconus may progress for 10 to 20 years and then slow.
It starts young, so the years of possible change come early. In its 2016 review of the Photrexa cross-linking drugs, the FDA described onset as generally occurring during puberty or early adulthood, which is why we watch teenagers' corneas closely. Being young is also one of the things we weigh when considering a referral for cross-linking.
Progression isn't limited to teenagers, though. In the clinical trials behind the FDA approval of cross-linking, the people with progressive keratoconus averaged 33 years old.
02
Does keratoconus progress the same way in both eyes?
Not necessarily. Keratoconus may affect only one eye at first; eventually both corneas become misshapen, although they might not be affected with the same severity. The AOA also notes that each eye may be affected differently.
We map and compare each eye separately for that reason. One eye can hold steady while the other is changing, and each one's maps decide its own next step. If only one eye has been diagnosed so far, the other still needs regular maps, because both corneas are eventually affected.
03
What are the signs keratoconus is getting worse?
Signs include a glasses prescription that keeps changing and vision that new glasses no longer make sharp. FDA reviewers described keratoconus as progressive thinning and steepening of the central cornea, which brings increasing nearsightedness, irregular astigmatism and a loss of the vision glasses can provide.
Glare and sensitivity to light are part of the picture as well; keratoconus causes them even in its earliest stages. Our article on what keratoconus vision looks like describes the ghosting, halos and doubled images in detail.
Because these changes usually build slowly, we track progression with corneal maps as well as symptoms.
04
How do eye doctors measure keratoconus progression?
By comparing measurements of the cornea over time. In the trials the FDA reviewed for cross-linking, the main measurement was Kmax, the maximum curvature of the cornea in diopters, taken at the start and again at months 1, 3 and 12.
| What we compare with your baseline | What a change can mean |
|---|---|
| Steepness of the cornea on topography, including Kmax | The cone is getting steeper |
| Thickness of the cornea (pachymetry) | The cornea is thinning |
| Irregular astigmatism | The cornea's shape is becoming more uneven |
| Your vision with glasses | Glasses correct it less well than before |
In those trials, eyes given a sham treatment (riboflavin drops without removing the surface layer or using UV light) steepened by an average of 0.5 diopter in one study and 0.6 diopter in the other, while treated eyes flattened by an average of 1.4 and 1.7 diopters at month 12. Those patients averaged 33 years old with a starting Kmax of 61 diopters, so your own numbers may look quite different.
The sham comparison lasted only the first 3 months: about 56% of sham-treated eyes had cross-linking by month 3 and 89% by month 6, and for those eyes the later results repeat the last measurement taken before treatment. So the trials don't show how fast an untreated cornea changes over a year.
That is why we compare the same kinds of maps against your own baseline at each visit.
05
Can you slow down keratoconus progression?
Yes, with corneal cross-linking. The AOA says cross-linking halts or slows progression and is indicated early after diagnosis, or later if the glasses prescription is still increasing. A corneal surgeon performs it; we decide with you when it's time, coordinate the referral and handle the cross-linking follow-up.
Cross-linking now comes in two forms. Standard epi-off cross-linking removes the cornea's surface layer first; its riboflavin drops are approved for progressive keratoconus, and the label says the safety and effectiveness of the procedure haven't been established in children younger than 14. Epioxa, an epithelium-on version, leaves the surface in place and is labeled for keratoconus in adults and children 13 and older.
Stop rubbing your eyes. Frequent eye rubbing, especially hard rubbing with the knuckles, is a risk factor for keratoconus, and our page on eye rubbing and keratoconus has ways to calm the itch instead.
If you're pregnant or planning a pregnancy, our page on keratoconus and pregnancy explains how we adjust monitoring during those months.
06
When is a sudden change in keratoconus an emergency?
A sudden change needs care right away. In a small number of cases the cornea swells and vision drops suddenly and significantly, an event called acute corneal hydrops.
- Sudden loss of vision in one or both eyes, even if it comes back, or sudden double vision: call 911.
- Sudden haze or clouding in an eye with keratoconus, or severe eye pain: call us right away at 310-828-2010 for a same-day exam, or go to an emergency room when we're closed.
- If you wear contact lenses and the eye turns painful, red, light-sensitive or suddenly blurry, or you see a white spot on the cornea: take the lens out and call us right away for a same-day exam, or go to an emergency room when we're closed.
- Don't rub the eye or patch it yourself, and bring your current lenses to the visit.
Our hours are Monday 10 to 5 and Tuesday to Friday 8 to 5, and we keep same-day slots for urgent problems.
07
How we track keratoconus progression at Cohenmehr Optometry
We start keratoconus care with a baseline of corneal topography, tomography and pachymetry, then compare every later visit against it, looking for more steepening, rising irregular astigmatism, thinning and worsening vision with correction.
How often our eye doctors in Los Angeles see you depends on your age and how fast your maps are changing. Young or changing eyes are typically re-mapped every few months, and stable adults may move to yearly checks. Keep the schedule even when your vision feels fine, since slow change is exactly what the maps are there to catch.
When the maps show progression, we start the conversation about cross-linking right away and coordinate the referral; our office is an Epioxa Keratoconus Certified Detection Center. Dr. Brandon Cohenmehr oversees every keratoconus evaluation, and lens designs are updated as the cornea changes.
08
Questions patients ask
Can Ortho-K lenses treat keratoconus?
No. Orthokeratology uses specially designed rigid gas permeable lenses to change the curvature of the cornea and temporarily improve focus; it is primarily used to correct nearsightedness. The FDA approval for one overnight Ortho-K lens, Paragon CRT, covers reducing nearsightedness in non-diseased eyes, and we fit Ortho-K only on appropriate corneas without keratoconus. For keratoconus, cross-linking is what halts or slows the disease, and scleral, rigid, hybrid or custom soft lenses correct the vision.
Can scleral lenses stop keratoconus from progressing?
No. Scleral lenses correct vision, but they don't halt the disease. FDA reviewers noted that glasses, rigid, scleral and hybrid contact lenses, and ring segments do not halt the progression of keratoconus. What a scleral lens does is vault over the cone on a layer of sterile saline, which masks the irregular corneal shape for sharper, steadier vision. That is why we pair it with regular corneal maps and, when the cornea is changing, cross-linking.
Do corneal ring segments stop keratoconus from progressing?
Not lastingly. Ring segments are small, clear implants a corneal surgeon places inside the cornea to flatten and regularize the cone; they can improve uncorrected vision and make contact lenses easier to fit. FDA reviewers listed them among the treatments that do not halt the progression of keratoconus, and the labeling for Intacs, one brand, says the procedure is likely to only temporarily stop progression. If your cornea is progressing, cross-linking comes first.
Can keratoconus come back after a corneal transplant?
It can. FDA reviewers listed recurrence of keratoconus in the transplanted graft among the possible complications of corneal transplantation, along with transplant failure, rejection, secondary cataract and secondary glaucoma. A transplant is necessary in only a few cases, and even afterward, glasses or contact lenses are often still needed to correct vision. We share the care before and after with your surgeon.
09
Sources
- American Optometric Association: Keratoconus
- MedlinePlus Genetics: Keratoconus
- FDA summary review: Photrexa, 2016
- DailyMed: Photrexa cross-linking label
- DailyMed: Epioxa cross-linking label
- FDA: Types of contact lenses
- FDA: Paragon CRT orthokeratology lens approval (P050031)
- FDA: Intacs labeling
Written by
Dr. Brandon Cohenmehr, OD
Specialty contact lenses, with a focus on Ortho-K, scleral lenses, and co-managing patients with keratoconus and other corneal disease. A graduate of SUNY College of Optometry.
About Dr. Brandon →
