This patient-education article is written by the cornea service at Suraj Eye Institute, Nagpur.

What Are Specialty Contact Lenses?

Specialty contact lenses are custom-designed lenses for eyes whose corneas are too irregular for standard spectacles or for ordinary soft lenses to give clear vision. The classical indication is keratoconus, where the cone-shaped cornea produces irregular astigmatism that spectacles cannot correct. Other indications include post-refractive ectasia, post-corneal-transplant eyes, severe dry eye and exposure keratopathy.

The optical principle is the same in every case: a rigid lens sits over the irregular cornea and the tear film fills the gap between them. Because the front surface of the rigid lens is smooth and regular, the eye now refracts light through a smooth optical surface, and clear vision is restored.

Specialty Contact Lens Fits — RGP vs Hybrid vs Scleral

Three Specialty Lens Designs on an Irregular Cornea

CORNEAL RGP

Small rigid lens sits on the cornea Tear film between lens and cornea

HYBRID LENS

Rigid centre with soft hydrogel skirt Comfort of soft + optics of rigid lens

SCLERAL LENS

Vaults the entire cornea Lands on sclera (yellow) Fluid reservoir bathes the cornea all day

Irregular cone-shaped cornea (keratoconus) shown in each panel for comparison.

Figure 1. Three specialty contact lens designs on an irregular (keratoconic) cornea. A corneal RGP is small, sits on the cone apex and the tear film fills the gap. A hybrid lens has a rigid optical centre with a soft hydrogel skirt — combining clear optics with the comfort of a soft lens. A scleral lens is large; it vaults the entire cornea and lands on the relatively flat sclera, with a continuous reservoir of preservative-free saline bathing the cornea all day — especially useful when the ocular surface is dry or scarred.

When Specialty Lenses Are Needed

  • Keratoconus — the commonest indication; soft lenses cannot mask the irregular astigmatism
  • Post-LASIK ectasia and post-refractive surgery
  • After corneal transplantation when graft astigmatism is high
  • Severe dry eye, exposure keratopathy or neurotrophic surface disease — scleral lenses provide continuous lubrication
  • High astigmatism not correctable with toric spectacles or soft lenses

The Fitting Process

Fitting a specialty lens is a structured process spanning several visits. Corneal tomography and AS-OCT measurement of sagittal height guide the choice of lens design and base curve. Trial lenses are inserted, the fit is assessed at the slit lamp with fluorescein, the lens parameters are refined and a final custom lens is ordered. Adaptation typically takes one to two weeks for RGP and hybrid lenses, slightly longer for scleral lenses.

Caring for Specialty Lenses

Cleaning, storage and replacement schedules differ between lens types. Scleral lenses must be filled with preservative-free saline before insertion. Tap water must never be used for rinsing lenses or cases — the risk of Acanthamoeba keratitis is real. We provide detailed care instructions at fitting and at every follow-up.

✔ Specialty Contact Lens Fitting at Suraj Eye Institute

Our optometry team fits rigid gas-permeable, hybrid and scleral lenses for keratoconus, post-refractive ectasia, post-corneal-transplant eyes and severe ocular surface disease. Fitting is guided by Anterion swept-source OCT tomography and AS-OCT sagittal height measurements, with extended follow-up to optimise comfort and clarity.

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Frequently Asked Questions

Will an RGP lens be uncomfortable?
There is a settling-in period of one to two weeks during which the lid edge adapts to the rigid lens. After that, most patients are comfortable for a full day of wear. Hybrid lenses (rigid centre, soft skirt) are usually more comfortable from the first wear.

What is the difference between an RGP and a scleral lens?
An RGP is small (about 9–10 mm) and sits on the cornea. A scleral lens is large (15–20 mm), vaults completely over the cornea and lands on the sclera. Scleral lenses give better stability, all-day comfort and a continuous fluid reservoir over the cornea — particularly helpful in dry eye and severe keratoconus.

Do specialty lenses stop keratoconus from progressing?
No. Specialty lenses restore vision but do not change the underlying corneal disease. The only treatment that halts keratoconus progression is corneal cross-linking, performed independently when progression is documented.

Can I sleep in scleral lenses?
No. All specialty lenses should be removed before sleeping. Closed-eye wear substantially increases the risk of microbial keratitis.

How long does a specialty lens last?
Typical replacement intervals are 12 months for RGP and hybrid lenses and 18–24 months for scleral lenses, sooner if the cornea shape changes, vision drops or the lens shows surface deposits.

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