Indications

Surgical management of keratoconus in patient intolerant of contact lens treatment.

Primary goal to restore contact lens tolerance and prevent need for penetrating keratoplasty.

Secondary goal to improve spectacle and uncorrected visual acuity.

Surgical management of post-LASIK ectasia.

Mild to moderate natural myopia.

Contraindications

Visually significant corneal scar.

Corneal thickness at Intacs entry site < 450 μm; thinnest pachymetry < 350.

Preoperative Procedure

1. Patient should not wear eye makeup on day of procedure.

2. Treat preexisting dry eye and blepharitis. Consider non-preserved lubricants, lid hygiene, punctual plugs, topical cyclosporine, and oral doxycycline for blepharitis.

3. Assess refraction, keratometry, and corneal topography for axis of Intacs placement and proper size of Intacs segments:

Nominal expected correction:

250 μm segments: -1.3 diopters

300 μm segments: -2.0 diopters

350 μm segments: -2.7 diopters

400 μm segments: -3.4 diopters

450 μm segments: -4.1 diopters

Note: Segments may be placed asymmetrically for noncentered cones. For peripherally displaced cones, one segment may be considered to improve asymmetry in corneal topography.

Instrumentation

Figure 25.1