Specialty soft contact lenses

For decades most keratoconus patients were managed exclusively with corneal GP lenses.

Although corneal GP lenses can provide excellent vision by correcting induced higher order aberrations, there are patients who can’t successfully wear them secondary to comfort or fit issues.

Modern specialty contact lens providers now have increased options for managing keratoconus patients secondary to new developments in design and manufacturing.

Currently available options include; corneal GP lenses (including piggyback), specialty soft lenses, hybrid lenses, and scleral contact lenses.

The underutilized option for keratoconus

Specialty soft contact lenses are an underutilized option for select keratoconus patients. Generally, soft lenses that are fit for the management of ametropia are molded and mass-produced.

They are designed to fit an average eye, relatively thin, and have few if any ways to adjust the fit parameters. However, soft lenses can be lathe cut and custom designed to fit an individual eye in a similar manufacturing process used for making gas-permeable lenses.

With that in mind, a soft lens can be designed to successfully fit and provide vision for some patients with mild to moderate keratoconus. Specialty soft lenses are best fit by approximately matching the sagittal depth of a soft lens with the anterior segment sagittal height for a given chord diameter.

The base curve, peripheral curves, and diameter can be modified to achieve a successful fit. Specialty soft lenses are manufactured with center thickness 2-4X that of traditional molded soft lenses. This increase in relative thickness allows them to mask mild to moderate amounts of corneal irregularity.

Keratoconus candidates for specialty soft lenses

Keratoconus patients who have only moderate loss of best-corrected visual acuity (20/40 – 20/100) with spectacles are candidates for specialty soft lenses. 

For these patients, keratoconus designed soft lenses may be a first choice or the second option after failure with corneal GP lenses. The patient has to accept that their vision won’t be as sharp as what they would get with a GP lens but the offset is that the lenses will likely be more comfortable.

The replacement schedule is typically 2-3 months.

How to get started

Many of the labs that manufacture GP lenses also have available keratoncus soft specialty lens designs. These lenses are fit either using diagnostic lenses or sagittal height measurements from corneo-scleral topography.

Utilize consultants for help with troubleshooting issues with fit or vision. Specialty soft lenses for keratoconus can be a successful go-to lens design for patients with mild to moderate keratoconus.