Topical losartan inhibits corneal scarring fibrosis and collagen type IV deposition after Descemet's membrane-endothelial excision in rabbits.

The purpose of this study was to examine the effect of topical and/or oral angiotensin converting enzyme II inhibitor and TGF-beta signaling blocker losartan on corneal stromal fibrosis that developed in rabbit corneas after Descemetorhexis removal of central Descemet's membrane and corneal endothelium. Twenty-eight New Zealand white rabbits were included and either had 8 mm central Descemetorhexis or sham control surgery without Descemetorhexis in one eye. Groups of 4 eyes without Descemetorhexis were treated for one month with no medications, topical losartan or oral losartan. Groups of 4 eyes with Descemetorhexis were treated with topical and oral vehicle, topical losartan, oral losartan, or both topical losartan and oral losartan for one month. Standardized slit lamp photos were obtained with central opacity intensity measured with ImageJ. The posterior fibrotic zone of corneas was measured on immunohistochemistry for alpha-smooth muscle actin (SMA) and keratocan using QuPath analysis. Collagen type IV expression in the posterior cornea was quantitated with ImageJ and duplex immunohistochemistry for collagen type IV and TGF beta-1. After Descemetorhexis, topical, but not oral, losartan decreased the intensity of central stromal opacity, reduced peripheral corneal scarring, and decreased alpha-smooth muscle actin myofibroblast fibrosis area compared to corneas that had Descemetorhexis and treatment with vehicles alone. Topical losartan decreased posterior stromal cellular, non-Descemet's membrane, collagen type IV production, that is likely stimulated by TGF beta as part of a negative regulatory feedback mechanism, compared to vehicle treatment at one month after Descemetorhexis. Topical losartan is likely to be effective in reducing corneal scarring fibrosis produced by traumatic injury, microbial infection, and some corneal diseases and surgeries.

Acute corneal edema decades after penetrating keratoplasty for keratoconus in eyes wearing scleral contact lenses.

PURPOSE: To report three cases of acute corneal edema occurring decades after penetrating keratoplasty (PK) for keratoconus in eyes wearing scleral contact lenses (ScCLs) with previously clear corneal grafts. METHODS: Retrospective chart review of three ScCL wearers presenting for sudden onset pain and blurred vision. Data extracted included clinical presentation, year and reason for PK, ocular medications and comorbidities, contact lens wearing history, results of any ancillary testing available including corneal topography, anterior segment optical coherence tomography (OCT), and specular microscopy surrounding the event, treatment and outcomes of intervention. The number of PK eyes fit with ScCLs in the author's practice was determined to estimate the prevalence of this event. RESULTS: The three patients each had a longstanding PK for keratoconus performed between 33-35 years prior to presentation and recurrent ectasia. Each patient presented with an acute, painful eye and reduced vision either 3 days, 4 months or 9 years after refitting into ScCLs. Each eye had well demarcated focal microcystic epithelial and stromal edema within the graft and crossing the wound margin onto the host cornea. Although a definitive break or detachment of Descemet's membrane was not visualized, the presentations suggest these were episodes of acute hydrops. CONCLUSIONS: Longstanding PKs with recurrent ectasia and acute focal edema suggestive of corneal hydrops is demonstrated in this case series of ScCL wearers. Although similar events have occurred as part of the natural history of post-PK corneas for keratoconus, the proximity of ScCL refitting to two of the events suggests some association.