Focal Weakening/Thinnest Corneal Point Proximity in Normal, Subclinical, and Keratoconic Corneas Using Motion-Tracking Brillouin Microscopy.

Purpose: To determine the proximity between the thinnest corneal point (TCP) and focal corneal weakening in normal, subclinical keratoconus (SKC), and manifest keratoconus (KC) eyes using motion-tracking Brillouin microscopy.

Design: Prospective cross-sectional study.

Participants: Ninety-five eyes from 95 patients were evaluated: 40 from bilaterally normal patients (controls), 40 from patients with SKC, and 15 from patients with manifest KC.

Three-Dimensional Mechanical Characterization of Normal, Subclinical, and Keratoconic Corneas Using Motion Tracking Brillouin Microscopy.

Purpose: To characterize the 3-dimensional (3-D) mechanical differences between normal corneas and those with subclinical keratoconus (SKC) or clinical keratoconus (KC) using motion-tacking (MT) Brillouin microscopy.

Design: Prospective cross-sectional study.

Methods: There were 50 eyes from 50 patients evaluated, including 20 Control eyes from 20 patients, 20 SKC eyes from 20 patients, and 10 stage I or II KC eyes from 10 patients.

Brillouin microscopy for focal biomechanical measurements in normal and keratoconic corneas: A narrative review.

Corneal mechanical weakness is widely recognized as the root cause of keratoconus and a primary driver for undesirable refractive surgery outcomes. Theory, finite element modeling, and initial data predict that focal rather than generalized weakening precipitates corneal mechanical decompensation. Direct, 3-dimensionally (3-D) localized in vivo corneal mechanical measurements thus have the potential to revolutionize keratoconus management and the surgical correction of myopia.

Topical Losartan in the Treatment of Stromal Scarring After Refractive Surgery.

Purpose: To review current guidelines for the prophylactic and therapeutic use of topical losartan to prevent and treat corneal scarring fibrosis in refractive surgery.

Methods: PubMed was used to search the medical literature.

Results: Scarring fibrosis of the cornea is typically associated with injury to, and defective regeneration of, the adjacent overlying epithelial basement membrane that controls transforming growth factor (TGF)-β passage into the stroma, leading to the development and persistence of myofibroblasts.

The Influence of the Epithelium Removal Method on the Outcomes of Photorefractive Keratectomy.

Purpose: To compare the outcomes and complications reported for alternative methods of removal of the corneal epithelium during photorefractive keratectomy (PRK).

Methods: Literature review.

Results: Excimer laser-based refractive surgery treatments are safe and effective, and PRK is one of the most common methods used to treat refractive errors.

Topical Losartan Treatment of Herpes Simplex Virus- or Varicella-Zoster Virus-Induced Corneal Scarring: A Case Series.

Introduction: Topical losartan has emerged as a promising therapeutic option for preventing and treating corneal scarring fibrosis. Its mechanism of action involves the inhibition of ERK-mediated signaling in the noncanonical TGF-beta pathways, promoting apoptosis of myofibroblasts and facilitating a return of corneal transparency. While numerous studies in rabbits and several human case reports have demonstrated its efficacy and safety, published data on its use in clinical scenarios remain limited.

Topical Losartan in the Management of Corneal Scarring Fibrosis: Update on Dosage, Efficacy, and Potential Epithelial Toxicity.

Losartan is an angiotensin II receptor blocker (ARB) that also inhibits transforming growth factor (TGF)-beta signaling by blocking the activation of extracellular signal-regulated kinase (ERK) in the noncanonical TGF-beta signaling pathway. Rabbit studies demonstrated the efficacy of topical losartan in reducing fibrotic scarring following a variety of corneal injuries, such as descemetorhexis, alkali burns, and photorefractive keratectomy (PRK). Several human case reports have subsequently shown the efficacy of topical losartan in treating scarring fibrosis resulting from surgical complications and infections.

Evaluating the Global Consensus on Keratoconus and Ectatic Diseases Agreements Reached on Subclinical Keratoconus.

Purpose: To evaluate the consensus agreements reached in the Global Consensus on Keratoconus and Ectatic Diseases project for subclinical keratoconus, specifically that posterior corneal elevation abnormalities must be present to diagnose mild or subclinical keratoconus.

Design: Literature review.

Methods: Database review (PubMed) was performed on January 2, 2024, to identify studies evaluating the ability of posterior corneal surface metrics to identify subclinical keratoconus using the following search terms: posterior corneal elevation; keratoconus screening; corneal ectasia; subclinical keratoconus; keratoconus suspect; and asymmetric keratoconus.

Epithelial Mapping Efficacy for Subclinical Keratoconus Identification.

Purpose: To evaluate the utility of automated epithelial thickness metrics to identify subclinical keratoconus (SKC) through epithelial thickness pattern comparisons between normal controls, (SKC), and manifest keratoconus (KC).

Design: Retrospective cross-sectional study.

Methods: There were 200 eyes from 200 patients evaluated, including: (1) 100 control eyes from 100 patients with bilaterally normal corneal topography/tomography and slit-lamp examination (controls); (2) 50 eyes from 50 patients with SKC; (3) 50 eyes from 50 patients with KC.

Riboflavin-UV crosslinking of the cornea: Wound healing and biomechanics.

The corneal wound healing response to Riboflavin-ultraviolet-crosslinking (RIB-UV-CXL) depends on the specific method used in treatment. The predominance of clinical evidence supports the classical "epithelium-off" RIB-UV-CXL method being more effective in halting ectasia progression than various "epithelium-on" methods, where the corneal epithelium is maintained intact. Corneal transparency results from the precise organization of collagen fibrils and extracellular matrix, along with transparent keratocytes.

Determining the Relationship Between Regional Epithelial Thickness, Corneal Toricity, and Corneal Power in Normal Corneas.

Purpose: To determine the relationship between regional epithelial thickness and corneal toricity and estimate the epithelium's impact on corneal power in normal corneas.

Methods: This was a retrospective case-control study evaluating 200 eyes from 200 patients categorized into one of three groups based on corneal toricity obtained with Scheimpflug imaging: (1) 80 non-toric (NT) eyes (< 0.50 diopters [D] in any meridian), (2) 80 with-the-rule (WTR) eyes (⩾ +1.

Insights from animal studies exploring the efficacy and safety of topical losartan, in prophylaxis and treatment of corneal scarring fibrosis.

Several studies in rabbits demonstrated the efficacy and safety of topical losartan, an angiotensin II receptor blockers (ARB) that modulates the TGF-β intracellular signaling pathways by inhibiting the activation of Extracellular Signal-regulated Kinase (ERK), in preventing or treating stromal fibrosis after a range of injuries such as Descemetorhexis, alkali burns, incisions, and photorefractive keratectomy (PRK). Several case reports have shown that topical losartan treatment is also efficacious and safe in humans to prevent or treat stromal fibrosis after many different injuries or diseases. Topical losartan penetrates the full thickness of the cornea and, therefore, can treat both anterior and posterior stromal fibrosis.

Topical Losartan Dosage Response and Corneal Toxicity at Higher Concentrations.

Purpose: The purpose of this study was to evaluate the efficacy and safety of higher dosages of topical losartan in an alkali-burn fibrosis model in rabbits.

Methods: In total, 18 rabbits had standardized alkali burns that trigger stromal fibrosis. Six eyes per group were treated with topical losartan (0.

Effect of Topical Losartan in the Treatment of Established Corneal Fibrosis in Rabbits.

Purpose: The purpose of this study was to evaluate the safety and efficacy of topical losartan in the therapeutic treatment of established corneal scaring fibrosis at 1 month after alkali burn in rabbits.

Methods: Standardized alkali burns were performed in 1 eye of 24 rabbits with 0.75N NaOH for 15 seconds.

Topical Losartan Inhibition of Myofibroblast Generation in Rabbit Corneas With Acute Incisions.

Purpose: The purpose of this study was to study whether deep central corneal incisions close during topical losartan treatment and the effect of topical losartan on myofibroblast generation after incisions in rabbit corneas.

Methods: Rabbits (12) had a 0.35-mm deep radial incision from the center of the cornea into the limbus in 1 eye that was approximated with a single 10-0 nylon suture 1 mm inside the limbus.

Corneal stromal localization of TGF beta isoforms in spontaneous persistent epithelial defects after PRK in rabbits.

The purpose of this study was to evaluate transforming growth factor beta (TGFβ) isoform localization in rabbit corneas with spontaneous persistent epithelial defects (PEDs) after photorefractive keratectomy (PRK). Four cryofixed corneas from a previously reported series of PEDs in rabbits that had PRK were evaluated with triplex immunohistochemistry (IHC) for TGFβ3, myofibroblast marker alpha-smooth muscle actin (α-SMA) and mesenchymal marker vimentin. One cornea had sufficient remaining tissue for triplex IHC for TGFβ1, TGFβ2, or TGFβ3 (each with α-SMA and vimentin) using isoform-specific antibodies.

Therapeutic visual rehabilitation in a patient with high hyperopia and flat cornea years after radial keratotomy.

A 51-year-old man was referred for refractive surgery evaluation. Spectacle dependence and poor visual quality in both eyes was his chief complaint. He cannot tolerate contact lenses.