Keratoconus Contact Lenses: Which Type Is Best for You?
FIG 1. NORMAL CORNEA
FIG 2. KERATOCONUS
Keratoconus is a progressive eye condition that affects the shape of the cornea, leading to distorted and blurred vision. While glasses may offer limited correction in the early stages, most patients eventually turn to contact lenses or surgical solutions to restore the clarity in their vision.
But not all lenses are created equal — especially when it comes to keratoconus contact lenses. With several types of speciality lenses available, including scleral contact lenses, rigid gas permeable (RGP), soft, and hybrid lenses, understanding the differences between them is key to finding the right solution for your eyes. In this blog, I compare the different types of contact lenses for keratoconus in terms of their design, comfort and effectiveness.
What is keratoconus?
The cornea is the clear, dome-shaped window at the front of your eye which focuses light onto the retina. But in people with keratoconus, this smooth surface begins to thin and bulge into a cone shape, resulting in blurry or distorted vision.
In Australia, keratoconus affects 1 in every 84 20-year-olds, making it the leading cause of corneal transplants in the country. Typically, the condition develops in people between 16 and 30 years old, stabilising by middle age, and affects both men and women equally.
Though keratoconus is progressive and cannot be fully cured, it is manageable with the right treatment. Specialised contact lenses can be a non-surgical treatment option that improves vision and quality of life.
Comparing Keratoconus Contact Lenses
| Lens Type | Solution for Keratoconus | Comfort Level | Suitability |
| Scleral lenses | Provide excellent vision and comfort by vaulting over the irregular cornea and resting on the sclera; ideal choice for all stages of keratoconus, particularly moderate to advanced cases. | Scleral lenses are considered the most comfortable option for keratoconus once properly fitted, especially for people with sensitive or dry eyes. |
|
| Corneal RGP lenses | Create an even surface over the irregular cornea. We fit people with RGPs if there are contraindications for sclerals, and sometimes for corneal grafts. | Less comfortable than soft lenses, especially for new users. Patients report that their comfort level usually improves after using them a few times. |
|
| Soft lenses | Traditional soft lenses are generally ineffective for keratoconus. They are suitable for people with regular corneas. | Soft lenses are comfortable contact lenses, but not suited for keratoconus treatment. |
|
| Hybrid lenses | A good option for patients intolerant to RGPs, used in mild keratoconus cases. | Moderately comfortable, more so than RGP lenses, but less than soft or scleral lenses. |
|
Scleral lenses
Solution for Keratoconus :
Provide excellent vision and comfort by vaulting over the irregular cornea and resting on the sclera; ideal choice for all stages of keratoconus, particularly moderate to advanced cases.
Comfort Level:
Scleral lenses are considered the most comfortable option for keratoconus once properly fitted, especially for people with sensitive or dry eyes.
Suitability:
- Ideal choice for all stages of keratoconus, particularly moderate to advanced keratoconus.
- Individuals with dry eye symptoms
- Also good for conditions other than keratoconus, such as other refractive errors, like myopia and astigmatism, hyperopia (long-sightedness), people with high refractive errors, or post-corneal surgical complications (eg, post-LASIK).
Corneal RGP lenses
Solution for Keratoconus:
Create an even surface over the irregular cornea.
If there are contraindications for sclerals, and sometimes for people with corneal grafts.
Comfort Level:
Less comfortable than soft lenses, especially for new users. Patients report that their comfort level usually improves after using them a few times.
Suitability:
Used in cases when there are contraindications for sclerals or people with corneal grafts.
Soft lenses
Solution for Keratoconus:
Traditional soft lenses are generally ineffective for keratoconus. They are suitable for people with regular corneas.
Comfort Level:
Soft lenses are comfortable contact lenses, but not suited for keratoconus treatment.
Suitability:
Can correct high levels of hyperopia, myopia and astigmatism, but needs a regular surface and not a lot of dry eyes.
Hybrid lenses
Solution for Keratoconus:
A good option for patients intolerant to RGPs, used in mild keratoconus cases.
Comfort Level:
Moderately comfortable, more so than RGP lenses, but less than soft or scleral lenses.
Suitability:
- Early or mild keratoconus or as back-up lenses
- Patients looking for a balance of comfort and vision
Scleral Lenses
FIG 3. SCLERAL LENS
Scleral lenses are large-diameter, gas permeable lenses that rest on the sclera (the white of the eye) and vault over the cornea. Scleral lenses are an excellent and effective treatment option for keratoconus. This is because they are wider and cover the cornea. They are rigid and hold their shape. They do not mould to the irregular cornea shape caused by keratoconus.
Scleral lenses can also be an option after a corneal graft. Given the lens vaults over the graft, scleral lenses can be a comfortable solution to restoring vision. However, not all corneal grafts can tolerate a scleral lens, and our optometrists can discuss this further with you.
Design and Function of Scleral Lenses
Scleral lenses create a tear-filled vault over the cornea, which helps to neutralise the irregular shape caused by keratoconus. This results in clearer and more stable vision. The fluid vault also provides constant hydration to the cornea, which can help with dry eye symptoms.
Scleral lenses for keratoconus require a precise fitting by an optometrist. Imaging and topography of the eye are typically used to customise the lens to the exact curvature of your eye.
Pros and Cons
Pros:
- Excellent vision correction for irregular corneas
- Very stable on the eye
- Comfortable for extended wear
- Hydrating for the eye
Cons:
- Requires consistent care and cleaning
- Some people need time to adapt to the lens as it is bigger, particularly with insertion and removal
Corneal RGP Contact Lenses
A Rigid Gas Permeable (RGP) lens is a hard contact lens which has oxygen-permeable polymers. Unlike soft contact lenses, which mould to the shape of the eye, corneal RGP lenses are “rigid” and maintain their shape as they sit over the cornea. This makes them a good treatment option for keratoconus. The breathable quality of the lenses still allows oxygen to pass through to maintain good eye health.
Design and Function
Compared to scleral lenses, RGP lenses are smaller and sit directly on the cornea. They help to create a smooth surface by masking the irregular shape caused by keratoconus.
Pros and Cons
Pros:
- Clear, sharp vision
- Durable and long-lasting, as they are less prone to tearing than soft contact lenses
- Less expensive than other specialised lenses
Cons:
- Prone to dislodging from the eye
- May not be suitable for advanced keratoconus
- Are more uncomfortable than scleral contact lenses, and therefore take longer to adapt to
Fig 4. RGP Contact Lens
Soft Lenses
Fig 5. Soft Contact Lens
Soft contact lenses are made of flexible plastics that fit the shape of your eye and allow oxygen to pass through. They are called “soft” lenses because they conform to the shape of your cornea.
They are ineffective for keratoconus as they mould to the conical shape of the cornea because of keratoconus. This does not provide adequate vision correction. Soft lenses are suited to myopia treatments, and can correct long-sightedness, astigmatism and also come as a multifocal.
Pros and Cons
Pros:
- Extremely comfortable
- Easy to wear and adapt to
- Good for a temporary solution to very mild keratoconus
Cons:
- Poor vision correction in moderate to severe keratoconus
- Shorter lifespan and need regular replacement (daily or monthly)
Hybrid Lenses
As the name suggests, hybrid lenses are a mix of RGP and soft lenses. They have a hard central portion and a soft skirt. This combines the clarity of RGP lenses with the comfort of soft lenses.
Pros and Cons
Pros:
- Good vision correction
- More comfortable and centred than RGP lenses
Cons:
- More costly than standard soft lenses
- Shorter lifespan than scleral lenses
Fig 6. Hybrid Lens
Factors That Determine Which Keratoconus Lenses Are Right for You
Choosing the right type of contact lens for keratoconus is not a one-size-fits-all decision. There are individual factors that determine lens suitability for both vision correction and long-term comfort.
1. Keratoconus Progression
Keratoconus can progress over time, and the severity of the condition affects lens selection:
- Early-stage keratoconus may be managed with hybrid or corneal RGP lenses, although many still opt for a scleral contact lens given the advanced comfort they provide.
- Moderate stages often require hybrid or scleral lenses for better corneal coverage and reshaping.
- Advanced keratoconus usually requires hard contact lenses for keratoconus, such as scleral lenses, which can vault over more pronounced corneal cones.
2. Corneal Thickness and Shape
The corneal shape and thickness, especially in areas affected by keratoconus, affect how well a lens fits and how effectively it corrects vision. Topography scans help determine the ideal lens vault and curvature.
- Scleral lenses are excellent choices for thin or irregularly shaped corneas. They avoid putting direct pressure on the cornea and provide a fluid reservoir.
- RGP or hybrid lenses can be suitable for flatter or less irregular corneas.
3. Lifestyle
Your daily activities will also influence the lens choice:
- Active lifestyles (like regular sports) require stable lenses like scleral or hybrid lenses that stay centred and are not dislodged easily.
- If you use screens for extended periods as part of your daily routine, scleral lenses are a great option. They offer consistent vision correction and hydration, which is essential to protect your eyes from screen-related damage and dry eyes.
4. Comfort
Comfort is a key factor in long-term lens wear and the success of keratoconus treatment. Most patients report that scleral lenses are the most comfortable when it comes to keratoconus. Hybrid lenses are a close second due to their larger size and stability compared to RGP lenses.
Optometrists use diagnostic tools, such as corneal topography and pachymetry, to evaluate the progression of keratoconus. Combined with a discussion about your lifestyle, expectations, and goals, these insights help create a personalised treatment plan to achieve the best possible vision and comfort.
How to check lens fitting and comfort level
To diagnose keratoconus and get an appropriate lens fitting, you can expect:
- A detailed eye exam with an eye refraction test, slit lamp examination, keratometry, corneal mapping and topography tests. These tests take measurements of the cornea.
- Trial lens fitting in-office
- Follow-up visits to assess lens comfort and vision
- Any adjustments for corneal health
If the fitting is too tight, you would feel tightness in your eye and potentially some redness afterwards. An indicator of a good fit is that you can wear it all day and continue with your daily activities without discomfort or the lens becoming significantly foggy. You can expect some redness, but with a good fit, this should be minimal, and your vision should be stable.
Conclusion
Keratoconus can be a challenging condition, but with the right type of contact lens, it’s entirely possible to manage its progression and live comfortably. From scleral to hybrid lenses, each option has its strengths and limitations. The key lies in working closely with your optometrist to find the lens that best suits your corneal shape, lifestyle, and vision. Contact our team to learn more.
