Hydrus Microstent Implantation: Teaching Video

I. Paul Singh, MD

Eyetube

I. Paul Singh, MD, shares a teaching video demonstrating Hydrus Microstent (Alcon) implantation in the eye of a patient with mild glaucoma. Financial Disclosure: Consultant (Alcon)

Painting a Clearer Picture of Corneal Scarring in Keratoconus

Topical losartan may offer a new treatment option.

Ethin S. Kiekhafer, OD, FAAO, and Jacob Lang, OD, FAAO

Modern Optometry

Keratoconus is a corneal dystrophy commonly diagnosed in early adolescence and adulthood characterized by progressive apical thinning, corneal scarring, irregular astigmatism, visual distortion, and decreased visual acuity. With early diagnosis and therapeutic intervention such as corneal crosslinking (CXL), when indicated, many patients perform well using rigid gas permeable or scleral lenses. However, corneal scarring can complicate the clinical picture, affecting an estimated 20% of patients with keratoconus.1 Corneal transplantation has historically been the only option for achieving visual improvement for these patients. Recently, the off-label use of losartan, an angiotensin II receptor blocker (ARB) commonly used in hypertension, has emerged as a promising intervention for reducing corneal scarring in keratoconus and possibly other pathologies of the cornea. Let’s take a look at some of the research. CORNEAL SCARRING The etiology and pathogenesis of keratoconus is complex and not fully understood. In simplest terms, it is considered a multifaceted amalgamation of factors including systemic conditions, genetic predispositions, and environmental factors such as contact lens wear, chronic eye rubbing, and allergies.2 Although each case is likely to have its own unique etiology, progressive or untreated keratoconus results in stromal collagen thinning, basement membrane (BM) disorganization, Bowman layer breaks, corneal fibrosis, and ultimately, vision loss.2 Other keratoconus-associated complications, such as acute corneal hydrops, can also result in visually debilitating corneal fibrosis. These factors have allowed keratoconus to persist as a leading indication for corneal transplantation in Western countries.1 At the molecular level, corneal fibrosis is driven by matrix metalloproteinase activity and other inflammatory mediators, damaging the extracellular matrix and exacerbating fibrosis. Another important key player in this process is transforming growth factor-beta (TGF-Β), a cytokine that is absent in a healthy stroma, which is safeguarded by the epithelial and endothelial (Descemet) BMs. Following injury to either membrane, TGF-Β1 present in the epithelium, tears, aqueous humor, and endothelial cells invades the stroma, leading to myofibroblast activation.3 In any nonhealing or chronic injury with persisting BM damage, adequate stromal TGF-Β concentrations allow the relatively opaque myofibroblasts to persist.

AAO Opposes NIH Research Funding Proposal

Eyetube

The AAO responds to a proposal by the NIH to limit indirect funding for research projects; Lumenis launches a new device to address lower lid laxity and impaired blinking; and AI Optics receives FDA clearance for a handheld retinal imaging system. Learn more about your ad choices. Visit megaphone.fm/adchoices