Corneal Dellen After Non-Penetrating Deep Sclerectomy In An Eye With Prior Penetrating Keratoplasty

To describe a case of peripheral corneal dellen localized in the host ring following non-penetrating deep sclerectomy (NPDS) with mitomycin C in an eye with previous penetrating keratoplasty. To present the surgical revision technique performed to limit the extension of the filtering bleb and its anatomical and functional outcomes after failure of conservative management.

Instituto de Microcirugía Ocular (IMO) - Grupo Miranza, Barcelona, Spain. Department of Cornea, Cataract and Refractive Surgery and Department of Glaucoma.

A 66-year-old patient with prior bilateral Laser-Assisted In Situ Keratomileusis (LASIK) developed progressive post-LASIK ectasia, more advanced in the left eye, requiring penetrating keratoplasty in both eyes. Subsequent phacoemulsification with intraocular lens implantation was uneventful. Prolonged topical steroid therapy led to steroid-induced glaucoma refractory to maximal medical treatment. NPDS with intraoperative mitomycin C (0.02%), a hydroxyethyl methacrylate (HEMA) implant (Esnoper V-2000®), and absorbable collagen matrix (DuraGen®) was performed in the left eye. Early postoperative course was favorable, with controlled intraocular pressure (IOP) without medication.

Two months later, the patient reported discomfort and foreign body sensation. Best-corrected visual acuity (BCVA) was 0.15 logMAR and IOP was 13 mmHg. A diffuse, temporally extended filtering bleb associated with conjunctivochalasis caused tear film instability and a peripheral temporal corneal dellen with significant thinning. Intensive topical therapy, including a bandage contact lens, failed due to intolerance and recurrent epithelial breakdown. To limit bleb extension, surgical revision was undertaken with temporal conjunctival resection, compressive conjunctiva–sclera sutures, and adjunctive fibrin glue–assisted conjunctival closure. At 6 months, BCVA improved to 0.0 logMAR, IOP was 10 mmHg without medication, bleb extension decreased, and the corneal lesion resolved.

Peripheral corneal dellen may occur in the host cornea after NPDS in eyes with prior penetrating keratoplasty. Excessive bleb extension can disrupt tear film distribution and induce localized thinning. In grafted eyes, progressive peripheral stromal loss may jeopardize graft integrity. Early identification of the underlying mechanical cause is essential. If conservative management fails, timely surgical revision should be considered to prevent further corneal compromise.