Do Hard Contacts Help Keratoconus?

Do Hard Contacts Help Keratoconus?

by Brian Chou, OD, FAAO, FSLS

March 19, 2024


If you wonder if hard contacts can help keratoconus, please read on! The short answer is that yes, hard contact lenses can help keratoconus. However, there is much more you need to know to understand what is meant by this.

“Hard Contacts” a Misnomer

Eye doctors today no longer prescribe the true “hard” contact lenses which were made of polymethyl methacrylate (PMMA) which were commonplace prior to 1978. PMMA lenses are completely impermeable to oxygen. PMMA lenses can cause eye health complications due to limiting the amount of oxygen to the cornea, the clear front dome of the eye. Today’s so-called “hard” contact lenses are rigid gas permeable (RGP), which are also called gas permeable (GP) lenses. As their name implies, GP lenses are highly permeable to oxygen.

Two Types of Gas Permeable Contacts

You should know that there are two main classes of gas permeable or “hard” contacts lenses today: corneal and scleral GP lenses. Corneal GP lenses are the legacy treatment for restoring vision in keratoconus. But corneal GP lenses often have drawbacks including reduced initial comfort, lens instability with dislodgement and ejection, and vision that drifts after their removal. Scleral contact lenses are increasingly the first-line treatment for restoring vision in keratoconus due to their improved comfort, incredible stability on the eye, and no vision drift after removal. Of course, scleral lenses are not right for all keratoconus patients, as some still do best with corneal GP lenses or even hybrid or soft lenses depending on multiple factors.

Gas Permeable Lenses Are the Mainstay for Vision Restoration

In keratoconus, the gold standard for vision restoration is well-prescribed gas permeable contact lenses. At the moment, there is no surgery that can restore vision in keratoconus to the high level of what rigid surface contact lenses can do. This means that all the surgeries done for keratoconus – including corneal transplantation, corneal cross-linking, Intacs, conductive keratoplasty, implantable contact lenses – will not optimize vision to the level of what a custom GP corneal or scleral lens can provide. This is why “hard contacts” help the majority of those with keratoconus, and fortunately so since contact lens treatment is often safer by avoiding potential surgical complications.

Gas Permeable Lenses Do Not Stop Keratoconus Progression

Long ago, corneal GP lenses were thought to prevent increased corneal distortion in keratoconus by pressing against the cornea. Researchers and clinicians today understand that corneal GP lenses do not retard the progression of keratoconus. There are even three studies that implied that corneal GP lenses may even bring about or exacerbate keratoconus. There is no evidence demonstrating that scleral lenses slow or promote the natural progression of keratoconus. For those with progressing keratoconus, especially in the teenage to early 20s, the only safe and effective treatment known to slow or halt disease progression, is corneal cross-linking surgery.

ReVision Optometry is a referral-based practice in San Diego providing contact lens services for patients with keratoconus. To schedule an appointment, request your appointment online, or call our office at 619.299.6064.