Application of piggy-back lens in the correction of severe keratoconus: A case study

This is a case study on the application of a piggy-back lens in the correction of severe keratoconus.

From the results of general eye examination, refractive state examination, and corneal morphology examination on the patient, it was determined that corneal protrusion and deformation of the right eye were obvious. The right eye was corrected using a piggy-back lens and the left eye with a rigid gas-permeable contact lens (RGPCL) alone.

The right-eye lens fit well and the lens coverage was good. Both the static and dynamic fit results for the left-eye lens were good. After wearing the glasses for one month, the patient attended a review and stated that the lenses were comfortable to wear. The patient's vision was good after wearing the lenses. No obvious congestion was found in the conjunctiva under a slit lamp. The effects on both eyes of wearing RGPCLs were favorable. The corneal curvature reduced and the corneal thickness only changed to a small degree.

For keratoconus patients, application of a piggy-back lens can improve corrected visual acuity, comfort levels, and safety, prolong the wearing time, and enhance the effect of orthokeratology.