AAOpt 2026: Scleral lens refits address edema and tube shunts in keratoconus

A thinner scleral lens with less central clearance offered a path to continued wear for a patient with severe keratoconus and focal corneal edema, according to a case presented at the American Academy of Optometry Annual Meeting, held in Anaheim, California. A second case showed impression-based scleral lenses restoring vision without bearing on glaucoma tube shunts in a patient with keratoconus.^1,2

Both patients depended on scleral lenses for functional vision, which ruled out stopping lens wear as a practical option. The cases show in-clinic examples of how optometrists adjusted the fit when a standard scleral lens approach fell short.

Managing corneal edema during scleral lens wear in severe keratoconus

Alexis Herstein, OD, MS, described a 51-year-old woman with severe bilateral keratoconus and no history of corneal crosslinking who presented with discomfort and difficulty removing her right scleral lens.¹ Right-eye visual acuity through her habitual 17.0-mm Boston Sight Scleral lens (BostonSight) was 20/25-2 after five hours of wear. The lens had a 0.3-mm center thickness, 350 µm of central clearance, and excessive inferior limbal clearance with inferior conjunctival prolapse.

Immediately after lens removal, slit lamp examination showed limbal injection, diffuse superficial punctate keratitis, a 0.5-mm epithelial bulla, localized edema, and diagonal endothelial folds. Tomography showed a right-eye thinnest pachymetry of 326 µm and maximum keratometry of 79.00 D, compared with 347 µm and 90.88 D in the left eye. Herstein noted the endothelial folds raised concern for reduced endothelial reserve, while a deep tear reservoir and thick lens may have limited corneal oxygen.¹

Herstein then refitted the eye with a 17.0-mm OneFit MED+ lens (Blanchard) in the same roflufocon D material (Dk 100; Contamac). The diagnostic lens showed 200 µm of central clearance and a 0.21-mm center thickness with no compression or impingement, and best-corrected acuity on over-refraction was 20/30+. Herstein attributed part of the acuity loss to poor wettability of the diagnostic lens surface and planned follow-up after two weeks of wear.

Impression-based scleral lenses for keratoconus with glaucoma tube shunts

David Dinh, OD, presented a 76-year-old woman with keratoconus and bilateral glaucoma tube shunts for primary open-angle glaucoma, referred by her ophthalmologist for scleral lens fitting.² Her regimen included dorzolamide, latanoprost, and netarsudil, and uncorrected acuity was 20/150 in the right eye and counting fingers at 2.5 feet in the left.

Diagnostic fitting produced conjunctival irritation, corneal touch, and edge impingement with blanching 360 degrees around the lens. Dinh attributed the poor fit to scleral distortion from the shunts combined with irregular corneal contours and switched to custom lenses made from a molded impression of the ocular surface.

With the impression-based lenses, best-corrected acuity improved to 20/30 in the right eye and 20/100 in the left. At dispensing, the lenses showed adequate central clearance without corneal touch, minimal edge lift, and no impingement over the tube shunts. Acuity remained stable at the final follow-up visit, at 20/30 to 20/40 in the right eye and 20/100 to 20/150 in the left.²

For optometrists fitting patients with advanced keratoconus, the Herstein case supports checking for bullae, edema, and endothelial folds immediately after lens removal. Reducing clearance and center thickness before discontinuing wear may preserve visual rehabilitation, although follow-up will determine whether the refit resolves the corneal findings.¹ Dinh concluded impression-based designs may reduce chair time and improve comfort when diagnostic fitting fails over altered scleral anatomy, though a single case cannot establish those benefits.²

References

1. Herstein A. A bullous balancing act: optimizing scleral lens fit in severe keratoconus. Poster presented at: Academy 2026 Anaheim; October 2, 2026; Anaheim, CA.

2. Dinh D, Burfield H. A customized approach to complex scleral fitting: impression-based lenses in keratoconus with tube shunts. Poster presented at: Academy 2026 Anaheim; October 2, 2026; Anaheim, CA.