CASE REPORT: Fitting a Scleral Lens after Corneal Intacs
Luis Ramirez, OD
Background
Intracorneal ring segments (ICRS or Intacs) may be used to improve corneal shape and reduce irregular astigmatism in patients with keratoconus. Often, these patients will remain with visual complaints such as ghosting or blurry vision with spectacle correction. Fitting soft contact lenses or corneal gas permeable lenses can present challenges due to corneal irregularity, mid-peripheral elevation changes, and potential for localized bearing over the intac segments. Scleral lenses offer an effective option for managing these patients by completely vaulting the cornea, creating a uniform refractive surface, and providing adequate vision and comfort1.
Case Presentation
44-year-old male with a history of bilateral keratoconus worse in the left eye (OS) presented for a medical evaluation for keratoconus and a contact lens fitting. He was diagnosed with bilateral keratoconus 18 years ago and underwent intacs surgery OS four years prior to the clinical presentation.
Manifest refraction revealed:
- OD: –3.25 –2.75 × 015 → 20/20
- OS: –5.75 –1.75 × 140 → 20/20–3
Despite being 20/20 with the manifest refraction, the patient still complained of subjective ghosting and blurry vision.
Slit lamp biomicroscopy revealed a bilateral 1+ bulbar conjunctival hyperemia with no follicles or papillae on the lower and upper palpebral conjunctiva. Lids and lashes were clean with no debris and regular lid margins. The right cornea had inferior steepening with no scarring, Vogt’s striae, or Fleischer’s ring. The left cornea had inferior steepening and 2 intac segments spanning from 1:30-8:00 and 8:00-11:30 in the mid-periphery with the incision scar at 12:30. Although mild touch was noted over the inferior segment at the 8 o’clock position, comparison with images from four years prior confirmed that the intacs remained stable (Fig. 1).
Fig.1. Slit lamp biomicrscopy image of the left eye. (A) Corneal intacs spanning 1:30–8:00 and 8:00–11:30 positions, four years post-implantation. (B) Current examination showing stable segment position and corneal clarity.
Fig 2. Tomography of the left eye. Axial curvature, pachymetry, and anterior/posterior elevation maps show paracentral inferior steepening, posterior elevation, and thinning consistent with keratoconus. Maximum keratometry: 52.8 D; thinnest corneal point: 539 µm.
The patient was then successfully fit into 16.0 mm diameter scleral lenses with toric peripheral curves and a Dk of 100 for both eyes. The scleral lens parameters were:
| Eye | Power | Central Thickness | Base Curve | SAG | Notes |
| OD | -0.75 SPH | 0.30 mm | 8.4 mm | 4000 µm | Adequate fit |
| OS | -0.75 SPH | 0.30 mm | 8.44 mm | 4000 µm | Adequate fit vaulting over intacs |
Both lenses exhibited minimal movement, approximately 200 µm of central vault, and appropriate limbal clearance after four hours of settling. There was no blanching or impingement noted. Importantly, the left lens demonstrated 100–200 µm of clearance over the intacs segments, indicating sufficient vaulting without mechanical interaction. Visual acuities with the scleral lenses were 20/20 in both eyes and the patient reported resolution of glare and ghosting.
Fig 3. Scleral lens over the cornea. (A) Slit lamp image demonstrating even clearance across the intacs. (B) Anterior segment OCT confirming 100–200 µm of vaulting over the intacs without touch.
Clinical Pearls
When fitting scleral lenses over corneas with intacs, it is essential to:
- Ensure sufficient apical and midperipheral clearance over the ring segments to prevent localized bearing and mechanical stress2.
- Use anterior segment OCT to verify vault uniformity and assess lens settling over the intacs.
- Scleral lenses can provide subjective visual improvement in patients with corneal intacs, even when best-corrected visual acuity measures 20/201.
Scleral lenses can provide stable, comfortable vision for patients post-intacs when adequate clearance is maintained over the segments and limbal regions.
References
- Montalt JC, Porcar E, España-Gregori E, Peris-Martínez C. Visual quality with corneo-scleral contact lenses after intracorneal ring segment (ICRS) implantation for keratoconus management. Cont Lens Anterior Eye. 2019;42(1):111-116. doi:10.1016/j.clae.2018.07.006
- Rathi VM, Mandathara PS, Dumpati S, Sangwan VS. Scleral lens after intracorneal ring segments in patients with keratoconus. Cont Lens Anterior Eye. 2018;41(2):234-237. doi:10.1016/j.clae.2017.10.013