A few years ago, a patient came into our store after being told by another clinic that contact lenses would never work for him. He had moderate keratoconus in both eyes. Soft lenses draped over his cone-shaped corneas and gave terrible vision. RGP lenses popped out constantly because his corneal shape could not hold them in place. Glasses gave him usable but frustrating vision with ghosting and halos at night. He was 28 years old and had essentially given up on contacts.
We referred him to a practitioner who fits scleral lenses. Eight weeks later, he was seeing 20/25 in both eyes, wearing his lenses comfortably for 14 hours a day, and telling everyone who would listen that scleral lenses changed his life. That is not an exaggeration. For certain eye conditions, scleral lenses genuinely are life-changing.
What Are Scleral Lenses and How Do They Work
Scleral lenses are large-diameter rigid gas permeable (RGP) contact lenses that vault entirely over the cornea and rest on the sclera, the white part of the eye. Unlike conventional contact lenses that sit on the cornea, scleral lenses never touch it. There is a fluid-filled space between the back of the lens and the front of the cornea, filled with preservative-free saline at insertion.
This design has three huge advantages. First, the rigid lens surface creates a perfectly smooth optical surface in front of the irregular cornea, which is why vision through a scleral lens is often dramatically sharper than through glasses or soft lenses for conditions like keratoconus. Second, the fluid reservoir constantly bathes the cornea in saline, providing uninterrupted hydration. Third, the lens rests on the sclera, which has far fewer nerve endings than the cornea, making the lens more comfortable than smaller RGP lenses that sit directly on corneal tissue.
Scleral lenses range from about 14.5mm to 24mm in diameter (for comparison, a typical soft lens is 14mm and a corneal RGP is 9-10mm). Most modern scleral lenses fall in the 15-18mm range. The larger the lens, the more it vaults over the cornea and the more stable it sits on the eye.
Scleral vs RGP vs Soft Lenses: The Full Comparison
Understanding where scleral lenses fit in the contact lens landscape helps explain when they make sense and when they are overkill.
| Feature | Soft Lens | Corneal RGP | Scleral Lens |
|---|---|---|---|
| Diameter | 14-14.5mm | 9-10.5mm | 14.5-24mm |
| Rests on | Cornea | Cornea | Sclera (vaults over cornea) |
| Material | Hydrogel / silicone hydrogel | Rigid gas permeable | Rigid gas permeable (high Dk) |
| Initial comfort | High | Low (adaptation needed) | Moderate to high |
| Vision on irregular corneas | Poor (drapes over irregularity) | Good (creates new surface) | Excellent (smooth optic + fluid reservoir) |
| Dry eye suitability | Poor (dehydrates) | Fair | Excellent (constant hydration) |
| Stability on eye | Good | Fair (can dislodge) | Excellent (rarely moves) |
| Handling difficulty | Easy | Moderate | Moderate (larger = easier to handle) |
| Cost per lens | $1-15 | $100-300 | $500-1,500 |
| Replacement | Daily to monthly | 1-2 years | 1-2 years |
Scleral lenses are not the right choice for everyone. If you have a normal cornea and no dry eye issues, soft lenses or corneal RGPs are simpler and cheaper. Scleral lenses shine when those other options fail.
Conditions That Scleral Lenses Treat
Scleral lenses are prescribed for specific medical conditions, not cosmetic preference. Here are the situations where they are commonly used:
| Condition | Why Sclerals Help | Alternative Options |
|---|---|---|
| Keratoconus | Vaults over the cone, creates smooth optical surface | Corneal RGP, hybrid lens, corneal crosslinking |
| Pellucid marginal degeneration | Covers large irregular area that RGPs cannot span | Large-diameter RGP, glasses (limited) |
| Post-corneal transplant | Accommodates irregular post-surgical shape | Corneal RGP, glasses |
| Severe dry eye (Sjögren's, GVHD) | Saline reservoir provides constant hydration | Moisture chamber glasses, punctal plugs |
| Stevens-Johnson syndrome | Protects damaged corneal surface | Bandage soft lens, moisture chambers |
| Post-LASIK ectasia | Corrects irregular astigmatism from complication | Corneal RGP, glasses |
| High or irregular astigmatism | Rigid surface corrects what soft lenses cannot | Toric RGP, custom soft toric |
Keratoconus is by far the most common reason I see patients fitted with sclerals. The National Keratoconus Foundation estimates that keratoconus affects roughly 1 in 2,000 people, though recent studies suggest the true prevalence may be higher. It typically begins in the teenage years and progresses through the twenties, making it a condition that affects people in the prime of their working and social lives.
Cost of Scleral Lenses in Canada
Let me be upfront about the cost, because it is the first thing most patients ask and the numbers cause sticker shock.
| Cost Component | Typical Range (CAD) | Notes |
|---|---|---|
| Initial fitting and consultation | $300-800 | Includes corneal mapping, trial lenses, multiple visits |
| Scleral lens (per lens) | $500-1,500 | Depends on design complexity and customization |
| Pair of lenses | $1,000-3,000 | Most patients need both eyes fitted |
| Annual solution costs | $200-400 | Preservative-free saline + RGP cleaning solution |
| Replacement (1-2 years) | $500-1,500 per lens | Fitting fee usually lower for replacement |
| Total first year | $1,500-4,200 | Fitting + lenses + solutions |
Those numbers sound high, and they are. But context matters. If you spread the cost over 18 months (typical lens lifespan), the monthly cost is often comparable to premium daily disposable soft lenses. And for patients with keratoconus or severe dry eye, sclerals provide vision and comfort that no other lens type can match.
Provincial health plans vary in their coverage of scleral lenses. Alberta Health does not cover contact lenses for most adults, but some conditions (particularly keratoconus) may qualify for assistance programs. Private insurance plans through employers often cover a portion of contact lens costs, though you may need a letter of medical necessity from your optometrist.
If your eye care provider recommends scleral lenses and you have questions about coverage or fitting, the team at Charm Optical can help you navigate the insurance side and connect you with a scleral lens specialist.
Insertion and Removal: The Learning Curve
I will not sugarcoat this: inserting scleral lenses for the first time is intimidating. The lens is large, you need to fill it with saline before putting it in, and you cannot blink during insertion or the saline spills. But the learning curve is shorter than most patients expect.
The standard insertion technique uses a plunger (a small suction cup device) to hold the lens. You fill the lens bowl with preservative-free saline, tilt your head forward so you are looking down into the lens, and bring your face down to the lens rather than bringing the lens up to your face. This gravity-assisted approach keeps the saline in the lens until it contacts your eye and seals.
Most patients go through these stages:
- Day 1-3: Takes 10-15 minutes. Multiple attempts. Some frustration. Completely normal.
- Week 1: Down to 3-5 minutes. Getting the angle right. Building confidence.
- Week 2-3: Under 2 minutes. Starting to feel routine.
- Month 2+: Under a minute. Muscle memory takes over.
Removal is generally easier than insertion. A small removal plunger (different from the insertion one) attaches to the lens edge and breaks the seal. Once you learn the technique, it takes seconds.
The biggest tip I give patients: do not try to learn insertion when you are tired, stressed, or rushed. Practice in the morning when you are fresh, in front of a well-lit mirror, with plenty of time. The anxiety of being in a hurry is what causes most insertion failures.
Daily Care and Maintenance
Scleral lens care is different from soft lens care. You need two products: a rigid gas permeable (RGP) cleaning and disinfecting solution for cleaning the lens, and preservative-free saline for filling the lens bowl at insertion. Regular soft lens solution is not appropriate for scleral lenses.
The daily routine looks like this: remove the lens at night, clean it with RGP solution using a rubbing technique, rinse thoroughly, and store it in fresh solution overnight. In the morning, rinse the lens with preservative-free saline, fill the bowl with saline, and insert. The whole cleaning process takes about two minutes per lens.
One common issue with scleral lenses is mid-day fogging, where the fluid reservoir becomes cloudy after several hours of wear. This happens because proteins and lipids from your tear film can seep under the lens edge. If it becomes bothersome, you can remove the lens, refill the saline, and reinsert. Some practitioners recommend adding a drop of non-preserved artificial tears to the saline reservoir at insertion to reduce fogging.
Who Should Not Wear Scleral Lenses
Scleral lenses are remarkably versatile, but they are not right for every patient or every situation:
- Patients with active eye infections. Any active infection needs to be treated and resolved before fitting scleral lenses. The sealed environment under a scleral lens could worsen an ongoing infection.
- Severe scleral or conjunctival disease. Since the lens rests on the sclera, any significant disease or scarring in that area can make fitting impossible or unsafe.
- Patients unable to handle the lenses. If dexterity issues (severe arthritis, tremors, limited hand mobility) prevent safe insertion and removal, sclerals may not be practical. Some patients work with a caregiver who learns the technique for them.
- Patients with normal corneas and no dry eye. If regular soft lenses or RGPs work fine for you, sclerals are unnecessary complexity and cost. They are a specialty solution for specialty problems.
Frequently Asked Questions
How much do scleral lenses cost in Canada?
Scleral lenses in Canada typically cost between $500 and $1,500 per lens, with a pair running $1,000 to $3,000. The fitting process adds another $300 to $800 for the initial consultation, trial lenses, and follow-up visits. Some provincial health plans and private insurance may cover a portion, especially for conditions like keratoconus. Ask your practitioner for a letter of medical necessity for your insurance claim. The lenses last one to two years with proper care, so the annual cost is often comparable to a premium monthly soft lens subscription.
Are scleral lenses comfortable?
Most patients find scleral lenses surprisingly comfortable. Because they vault over the entire cornea and rest on the less-sensitive sclera, they avoid the corneal nerve endings that make smaller RGP lenses uncomfortable. The saline-filled reservoir between the lens and cornea provides constant hydration, which many dry eye patients describe as immediately soothing. Initial adaptation takes a few days as your eyelids get used to the lens edges, but most patients report excellent comfort within the first week.
How long can you wear scleral lenses per day?
Most practitioners recommend a maximum of 12 to 16 hours of daily wear. Your specific limit will depend on your corneal health, tear production, and how much oxygen your cornea needs. Scleral lenses should always be removed at night. If you experience fogging or reduced vision after several hours, you may need to remove the lens, refill the saline reservoir, and reinsert. Your practitioner will guide you on building up wear time during the adaptation period.
Can you sleep in scleral lenses?
No. Scleral lenses are daily wear lenses only. Sleeping in them restricts oxygen to the cornea beyond safe limits and can cause corneal swelling (edema), new blood vessel growth (neovascularization), and infections. Remove them every night, clean them with RGP solution, and store them properly. This rule applies to naps as well.
How long does it take to learn to insert scleral lenses?
Most patients learn comfortable insertion within one to two weeks of daily practice. The first few attempts can take 10 to 15 minutes and feel awkward, which is completely normal. By the end of the first week, most people get it down to two to three minutes. By the end of the first month, insertion typically takes under a minute. A plunger tool makes the process much easier than trying to balance the lens on your fingers.
Do scleral lenses work for severe dry eyes?
Yes. Scleral lenses are one of the most effective treatments for severe dry eye conditions including Sjogren's syndrome, graft-versus-host disease, Stevens-Johnson syndrome, and exposure keratopathy. The saline reservoir provides constant corneal hydration, protects the surface from environmental exposure, and reduces blinking friction. Many severe dry eye patients who could not tolerate any other contact lens find sclerals comfortable and describe them as life-changing.
Can you swim or shower in scleral lenses?
Showering is generally fine because the sealed vault protects against water reaching the cornea. Swimming is riskier. While the scleral seal offers better protection than soft lenses, it is not guaranteed watertight. If you swim with sclerals, wear tight-fitting goggles and disinfect the lenses thoroughly afterward. Avoid hot tubs entirely. The combination of heat, chemicals, and bacteria increases infection risk regardless of lens type.
This article is for informational purposes only and does not constitute medical advice. Scleral lenses require a specialized fitting from a qualified eye care professional. Consult your optometrist or ophthalmologist to determine if scleral lenses are appropriate for your condition.