GP lens eye Rounds

KERATOCONUS: Contact Lens Management Decision-Making

Emily Gottschalk OD, FAAO

What is the role of contact lenses in managing Keratoconus?

• Patient not correctable to 20/20 or experiences visual distortion in spectacles.
  • Commercially available soft contact lenses for mild cases; can decenter on steep corneas.¹¹
  • Custom soft toric lenses with high center thickness to mask some corneal irregularity that cause aberrations.
  • Specialty keratoconic soft lens designs have high center thickness, high modulus material, and steep base curve radii.¹¹
  • Gas permeable contact lenses act as a regular refracting surface to mask the irregular corneal surface.¹²
    • Corneal GP lenses are preferable for central and paracentral nipple cones and challenging for oval or decentered cones.¹³ To aid in centration, stabilization, and comfort a piggyback system can be utilized with soft contact lens under the corneal GP.
    • Hybrid lenses can offer the optics of a GP lens with increased comfort and stabilization due to the soft skirt.¹¹
    • Scleral lenses are large diameter high Dk GP lenses that vault over the entire cornea and limbus and land on the sclera. As they do not land on the cornea, scleral lenses can be fit on advanced stage keratoconus where other lens designs are unstable. There is a fluid reservoir between the lens and the cornea that masks surface irregularity and provides lubrication.¹⁴

Sources

1. Barnett M, Mannis MJ. Contact Lenses in the Management of Keratoconus. Cornea 2011;30:1510-1516.
2. Griffiths M, Zahner K, Collins M, Carney L. Masking of irregular corneal topography with contact lenses. CLAO J 1998;24:76–81.
3. Barr JT, Zadnik K, Wilson BS, et al. Factors associated with corneal scarring in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study. Cornea 2000;19:501–507.
4. Schornack MM, Patel SV. Scleral lenses in the management of Keratoconus. Eye & Contact Lens 2010;36:39-44.