How VKC affects the eye
Vernal keratoconjunctivitis (VKC) is a chronic, bilateral inflammation of the conjunctiva (the tissue lining the lids and covering the white of the eye) and the cornea (the clear front window). It typically starts in childhood. Its symptoms include intense itching, light sensitivity, a white stringy discharge, watering, a gritty feeling, and pain when the cornea is involved.[2]
It is rare in some places and common in others. Estimated prevalence ranges from fewer than 2 per 10,000 in the United States to as high as 1,100 per 10,000 in parts of Africa.[1] Although it was long seen as a simple allergy, about half of people with VKC don’t show allergic sensitization on testing, and several inflammatory pathways are involved.[1]
VKC usually settles around puberty, but not always. About 10% of people with VKC are adults, some whose childhood disease carried on and some who first developed it after puberty. Adult VKC tends to be long-lasting, with severe inflammation and a higher risk of scarring of the conjunctiva.[3]
What VKC can do to the cornea
- Shield ulcers. These corneal sores are one of the most severe late complications. Untreated, they can cause permanent loss of vision.[11]
- Keratoconus. The cornea thins and bulges into a cone, blurring vision. It is one of the most common corneal complications of VKC, and it tends to be more severe and progress faster in people with VKC.[4]
- Limbal stem cell deficiency and scarring. Long-standing inflammation can damage the stem cells at the edge of the cornea, leaving a hazy, scarred surface.[9]
- Steroid side effects. Cataract and glaucoma can follow long use of steroid drops.[2]
How often keratoconus develops is debated. A Turkish study of 82 people with VKC found a keratoconus pattern in 26.8% of eyes using a sensitive mapping method.[5] An Italian study of 651 patients with VKC at a children’s hospital found keratoconus in only 0.77%.[6] Different populations and methods probably explain much of the gap. Either way, specialists recommend watching children with VKC for keratoconus.[4]
How a scleral lens can help
A scleral lens is a large rigid gas-permeable lens that rests on the sclera (the white of the eye) and arches over the whole cornea without touching it. It is filled with sterile saline before it goes in, and that saline stays over the cornea while it is worn.
In VKC, the lens is mainly used for what the disease leaves behind:
- Clearer vision with keratoconus or scarring. The saline layer smooths over a cone-shaped or uneven cornea optically, often giving sharper vision than glasses.
- A better environment for a damaged surface. In eyes with limbal stem cell deficiency, the aim is to keep the cornea bathed and protected from the lids.[7]
It doesn’t calm the allergy. The inflammation itself needs medical treatment.
What the research shows
The evidence is small. We found two small series and a few individual cases. There are no trials.
A VKC series from India. Researchers reviewed four patients (seven eyes) with VKC who wore PROSE scleral lenses, a fluid-filled custom design. Five eyes had keratoconus and two had limbal stem cell deficiency. Their average age was 17.5. Average vision improved from 0.4 to 0.18 logMAR (roughly 20/50 to 20/30) at a mean follow-up of 14.8 months, with about 8 hours of wear a day. Two of the three patients with keratoconus had already failed with standard rigid lenses.[7]
That series also shows the risks of advanced keratoconus. Two of the four patients developed acute hydrops, a sudden swelling of a thinned cornea, at 2 and 12 months of lens wear. Both needed treatment, and their vision with the lens dropped by more than two lines because of scarring.[7] The report doesn’t say the lens caused the hydrops.
Children. In a study of 15 patients aged 16 or younger fitted with fluid-filled scleral lenses at the same center, two eyes had both keratoconus and VKC. Across the whole group, vision improved by two lines or more in 85% of eyes. But in 45% of eyes, vision dropped by two lines or more after about 4 hours of wear because tear debris collected in the saline.[8] A US center’s 21-year review of 209 children’s eyes fitted with scleral lenses included a small number with corneal scarring after VKC.[10]
A long-term case. One man with VKC was followed for more than 25 years. He needed drops, immune-suppressing tablets, surgery for stem cell damage, and cataract surgery. A scleral lens added late in his care improved his vision further, and he reached 20/25 in both eyes with a stable surface.[9] The lens was one piece of a long, combined treatment plan.
Other options, compared
Medicine comes first. VKC treatment ranges from antihistamine drops and steroids to cyclosporine and tacrolimus drops.[2] An American Academy of Ophthalmology review found level I evidence that steroid-sparing drops, mostly cyclosporine and tacrolimus, improve the signs and symptoms of VKC in children.[12] Verkazia (cyclosporine 0.1%) is FDA-approved for VKC in children and adults. It is used four times a day, and contact lenses should be removed before each dose and reinserted 15 minutes later.[13]
Shield ulcers that don’t heal with drops may need surgical debridement, sometimes with an amniotic membrane graft, or a steroid injection under the upper lid. In a review of 10 studies covering 398 patients, almost all ulcers resolved or improved.[11]
Keratoconus with VKC can be treated with cross-linking to slow progression. Cross-linking and corneal transplants appear to work as well as in people without VKC, but complications after surgery are more common, so inflammation and eye rubbing need tight control.[4]
| Option | What it does | Typically suited to |
|---|---|---|
| Antihistamine and mast-cell stabilizer drops | Reduce itch and allergic reaction | Mild disease and seasonal control |
| Cyclosporine or tacrolimus drops | Long-term control of inflammation | Moderate to severe VKC; reduces steroid use |
| Steroid drops | Calm flares quickly | Short courses; long-term use risks cataract and glaucoma |
| Shield ulcer surgery | Removes plaque, aids healing | Ulcers that don’t heal with drops |
| Corneal cross-linking | Stiffens the cornea to slow keratoconus | Progressing keratoconus |
| Glasses or corneal rigid lenses | Correct vision | Mild keratoconus or scarring |
| Scleral lens | Smooths an irregular cornea and holds saline over it | Keratoconus or scarring left by VKC, once inflammation is controlled |
| Corneal transplant | Replaces a scarred or thinned cornea | Advanced disease not helped by lenses |
Questions to ask a scleral lens fitter
- How many children or young adults with VKC have you fitted?
- Is the eye calm enough to start, and how will you work with the doctor treating the VKC?
- Has the keratoconus been checked for progression, and should cross-linking come first?
- What should we do with the lenses during an allergy flare?
- How should we time drops such as cyclosporine around lens wear?
- If vision clouds after a few hours, what should we do?
- Who will teach us insertion and removal, and what signs mean we should remove the lens and call?
Common questions
Will a scleral lens treat my child's VKC?
No. VKC is treated with eye drops such as antihistamines, steroids, cyclosporine, or tacrolimus. A scleral lens is used for a different job: restoring vision when VKC has left keratoconus or scarring, or helping protect a damaged cornea. The drops still matter.
My child has VKC and keratoconus. What comes first?
Ask the cornea specialist. Keratoconus tends to be more severe and to progress faster with VKC, so specialists watch closely and may recommend cross-linking to slow it. Scleral lenses correct vision but don't stop progression. Controlling the allergy and stopping eye rubbing are part of the plan too.
Can my child use Verkazia drops with a scleral lens?
The FDA label says to remove contact lenses before each dose and wait 15 minutes before putting them back in. It's given four times a day, so ask your doctor and fitter to plan a schedule that works around school and lens wear.
Why does vision with the lens get cloudy after a few hours?
Debris from the tears can build up in the saline under the lens. In one pediatric study that included children with VKC, this was common after a few hours of wear. Your fitter may suggest taking the lens out to refill it, or changes to the fit. See our guide on midday fogging.
Will VKC go away?
It usually settles around puberty, but not always. Some people continue to have it as adults, and a smaller group first develop it after puberty. Damage already done, such as keratoconus or scarring, doesn't go away when the allergy does.