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How Many Contact Lenses Are Used in Keratoconus Piggyback Fitting?

Keratoconus piggyback fitting uses two contact lenses on each fitted eye: a soft contact lens is placed directly on the cornea, followed by a rigid gas-permeable lens on top, so someone using the system in both eyes would wear four lenses at a time. The soft lens primarily acts as a cushioning layer over the irregular corneal surface and can improve stabilization and tolerance of the rigid lens, while the rigid lens provides the more regular optical surface needed to improve vision affected by keratoconus. In a clinical study involving 16 patients and 29 eyes that couldn't comfortably tolerate rigid lenses alone, piggyback fitting improved visual acuity over rigid-lens wear in 89.7% of eyes, while the remaining 10.3% maintained similar visual acuity. Another study involving 40 eyes from 26 patients reported satisfactory comfort, wearing time, and vision in 87.5% of fitted eyes, supporting piggyback systems as an option when rigid lenses alone cause discomfort or fitting problems. Because two separate lenses sit over the same cornea, fitting also requires attention to oxygen transmission, lens movement, and corneal health rather than simply placing one lens over another.

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How Many Contact Lenses Are Used in Keratoconus Piggyback Fitting?

Keratoconus piggyback fitting uses two contact lenses on each fitted eye: a soft contact lens is placed directly on the cornea, followed by a rigid gas-permeable lens on top, so someone using the system in both eyes would wear four lenses at a time. The soft lens primarily acts as a cushioning layer over the irregular corneal surface and can improve stabilization and tolerance of the rigid lens, while the rigid lens provides the more regular optical surface needed to improve vision affected by keratoconus. In a clinical study involving 16 patients and 29 eyes that couldn't comfortably tolerate rigid lenses alone, piggyback fitting improved visual acuity over rigid-lens wear in 89.7% of eyes, while the remaining 10.3% maintained similar visual acuity. Another study involving 40 eyes from 26 patients reported satisfactory comfort, wearing time, and vision in 87.5% of fitted eyes, supporting piggyback systems as an option when rigid lenses alone cause discomfort or fitting problems. Because two separate lenses sit over the same cornea, fitting also requires attention to oxygen transmission, lens movement, and corneal health rather than simply placing one lens over another.

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Who Is a Good Candidate for Piggyback Contact Lenses?

Piggyback contact lenses are most often considered for people with keratoconus who can achieve useful vision with a rigid lens but struggle to wear it because of discomfort, poor centration, excessive movement, or repeated contact with the cone. Clinical reviews also identify significant corneal staining, scarring, and other situations where the rigid lens causes mechanical irritation as reasons a practitioner may consider adding a soft lens underneath. In one study of 29 keratoconic eyes that couldn't tolerate rigid lenses alone, piggyback fitting was used for stabilization and comfort in 13 eyes, additional comfort in 5 eyes, and protection of the cone in 11 eyes. The approach can therefore be particularly useful when the optical correction from a rigid lens is satisfactory but its physical interaction with an irregular cornea makes continued wear difficult. It isn't automatically the best choice for every person with keratoconus, however, because oxygen delivery, corneal condition, lens handling, and the availability of other specialty fitting options also need to be considered before choosing a two-lens system.

How Does a Piggyback Lens System Improve Comfort?

A piggyback lens system can improve comfort by placing a soft lens between the cornea and the rigid lens, reducing direct mechanical contact with the irregular or protruding area of a keratoconic cornea. Clinical literature describes the soft lens as a protective layer that can cushion the cone, reduce irritation, and help the rigid lens remain more stable during blinking and eye movement. In one study of 40 keratoconic eyes, 35 eyes, or 87.5%, achieved acceptable comfort, wearing time, and visual acuity with a piggyback system after experiencing difficulty with rigid lenses alone. Another study involving 29 eyes specifically identified improved comfort, lens stabilization, and protection from mechanical trauma as reasons for using the two-lens approach. The added cushioning doesn't eliminate the need for careful fitting, since the practitioner still needs to make sure both lenses move appropriately and allow sufficient oxygen to reach the cornea.

How Are Piggyback Contact Lenses Fitted for Keratoconus?

Piggyback fitting usually begins by selecting a soft lens that centers well and provides a stable surface over the irregular cornea before the rigid lens is added. Once the soft lens is in place, the practitioner may take keratometry measurements over it to help select an appropriate starting curvature for the rigid lens rather than relying only on measurements of the bare cornea. The rigid lens is then placed over the soft lens and assessed under magnification for centration, stability, and movement with each blink, with an ideal fit allowing both lenses to move appropriately rather than behaving as one fixed unit. Fluorescein evaluation can also be used to examine the relationship beneath the rigid lens, helping the practitioner identify excessive bearing, unwanted contact over the cone, or areas where clearance is greater than intended. Several trial combinations may be needed before the practitioner achieves an acceptable balance of movement, centration, corneal clearance, vision, and comfort, since changing the power or geometry of the underlying soft lens can alter how the rigid lens fits on top.

Piggyback Lenses vs. Scleral Lenses for Keratoconus

Piggyback and scleral lenses can both be considered when a standard corneal rigid lens is uncomfortable or unstable, but they achieve that goal in very different ways. A piggyback system combines two lenses on the same eye, using a soft lens beneath a smaller rigid lens to cushion the cornea and improve stability, whereas a scleral lens is a single large-diameter rigid lens that vaults over the cornea and rests on the tissue surrounding it, leaving a fluid reservoir between the lens and corneal surface. Scleral lenses can be particularly useful for very steep, highly irregular, or more advanced keratoconus because their larger diameter provides a stable optical surface without relying on the cornea for support. Piggyback systems require patients to insert, remove, clean, and store two separate lenses per eye, which can make daily handling and maintenance more involved, while scleral lenses eliminate the second lens but have their own learning curve because they must be filled with fluid before insertion and positioned without trapping air bubbles. Ultimately, the better option depends on factors such as the severity and shape of the cornea, comfort, lens stability, handling ability, and how well each design performs during an individualized fitting assessment.

Learn More About Keratoconus Piggyback Fitting

How long can you wear piggybank contact lenses each day?

Daily wearing time varies according to lens fit, corneal health, oxygen transmission, and individual tolerance rather than following one fixed limit. In one clinical study of keratoconus patients, daily piggyback lens wear ranged from 3 to 16 hours, with an average of about 11.7 hours, although wearing schedules should be determined individually by an eye care professional.

Can piggybank contact lenses slow the progression of keratoconus?

No. Piggyback lenses are used primarily to improve vision, comfort, and lens tolerance, rather than to stop the underlying corneal thinning and shape changes associated with keratoconus. Treatments intended to stabilize progressive keratoconus work differently by targeting the corneal tissue itself.

Can piggybank contact lenses cause complications?

Complications are possible, particularly when the lenses don't fit properly or the cornea receives insufficient oxygen; reported issues include corneal epithelial irritation, conjunctival inflammation, and abnormal blood vessel growth into the cornea. Modern highly oxygen-permeable lens materials have reduced some of the oxygen-related concerns associated with older piggyback systems, but regular eye examinations are still needed to monitor corneal health.

Do you have to wear a piggybank lens system permanently?

Not necessarily, as some people use piggyback lenses temporarily while improving their tolerance of rigid lenses or addressing fitting-related irritation. In one study, most participants used the system for 3 to 12 months, with an average of about 6 months, before eventually returning to rigid lenses alone, although some continued to require the two-lens system.

References

Contact Lens Management of Keratoconus. Clinical and Experimental Optometry. Source URL. Published June 23, 2015. Accessed August 21, 2026.

Current Perspectives in the Management of Keratoconus With Contact Lenses. Eye. Source URL. Published July 8, 2020. Accessed August 21, 2026.

High Dk Piggyback Contact Lens System for Contact Lens-Intolerant Keratoconus Patients. Clinical Ophthalmology. Source URL. Published March 3, 2011. Accessed August 21, 2026.

Management of Keratoconus: An Updated Review. Frontiers in Medicine. Source URL. Published June 20, 2023. Accessed August 21, 2026.

Nonsurgical Procedures for Keratoconus Management. Journal of Ophthalmology. Source URL. Published December 21, 2017. Accessed August 21, 2026.

Update on Contact Lens Treatment of Keratoconus. Turkish Journal of Ophthalmology. Source URL. Published August 26, 2020. Accessed August 21, 2026.