Improving Refractive Outcomes in Keratoconic Eyes

Two recent meta-analyses help inform management strategies.

Abdulkader Almosa, BS, BGS, and Zaina Al-Mohtaseb, MD

Cataract and Refractive Surgery Today

KEY TAKEAWAYS Recent research assessed how to improve refractive outcomes in eyes with keratoconus A meta-analysis of 14 clinical studies found that the implantation of corneal allogeneic intrastromal ring segments significantly improved the distance visual acuity of patients with keratoconus A meta-analysis of 16 observational studies found that posterior chamber ICLs (both the Visian and EVO models, STAAR Surgical) significantly improved the vision of patients with keratoconus Visual and Topographic Outcomes After Corneal Allogeneic Intrastromal Ring Segments for Keratoconus: A Systematic Review and Meta-Analysis Friedrich M, Auffarth GU, Soiberman U, Augustin VA, Khoramnia R, Son HS1Industry support for this study: None ABSTRACT SUMMARY This systematic review and meta-analysis evaluated visual, refractive, and topographic outcomes after the implantation of corneal allogeneic intrastromal ring segments (CAIRS) in keratoconic eyes. The investigators screened major medical literature databases and included 14 peer-reviewed clinical studies comprising 442 eyes total. The primary outcome was the change in patients’ corrected distance visual acuity (CDVA), with secondary outcomes including their uncorrected distance visual acuity (UDVA), spherical equivalent (SE), refractive cylinder, keratometry parameters, higher-order aberrations (HOAs), and postoperative complications. STUDY IN BRIEF A systematic review and meta-analysis of 14 clinical studies (442 eyes) found that the implantation of corneal allogeneic intrastromal ring segments (CAIRS) significantly improved the uncorrected and corrected distance visual acuity of patients with keratoconus and reduced their keratometric values with a low rate of complications. WHY IT MATTERS CAIRS are a minimally invasive, tissue-based alternative to synthetic intrastromal corneal ring segments and keratoplasty in select keratoconus patients. The improvements in visual, refractive, and topographic outcomes combined with a favorable safety profile demonstrated in this study suggest that CAIRS could offer a way to improve the vision of patients with keratoconus while also reducing their dependence on contact lenses. Pooled analysis demonstrated a mean improvement in patients’ CDVA and UDVA of 0.37 logMAR and 0.43 logMAR, respectively—approximately 4 Snellen lines. The SE improved by 4.59 D, and maximum keratometry was reduced by 4.49 D. Reductions were also observed in mean keratometry values and total HOAs, and the thinnest pachymetry reading remained relatively stable. One reported severe adverse event (0.2%) involved acute graft rejection and required CAIRS explantation.

Refractive Lens Exchange and the Evolving Surgical Management of Presbyopia

George O. Waring IV, MD, FACS; and Dagny C. Zhu, MD

Eyetube

George O. Waring IV, MD, FACS, speaks with Dagny C. Zhu, MD, about refractive lens exchange and her same-day bilateral refractive lens exchange workflow in an office-based surgery setting. Dr. Zhu discusses how refractive lens exchange fits into her cash-pay refractive practice, how her team screens and evaluates candidates, and the steps involved when patients proceed from consultation to surgery on the same day. She also shares her approach to diagnostic testing, patient counseling, premium IOL selection, oral sedation, femtosecond laser sequencing, refractive accuracy, and IOL calculations in eyes with a history of corneal refractive surgery.

A Primer on FAF

Even with the advances in imaging technology, fundus autofluorescence remains integral to our imaging protocols. Here’s why.

Thomas Ach, MD, MSc, FEBO, and Andreas Pollreisz, MD

Retina Today

KEY TAKEAWAYS With fundus autofluorescence (FAF), areas of increased or decreased autofluorescence reflect local changes in fluorophore levels, cell health, and overlying tissue, making it a valuable tool for monitoring disease activity and progression. FAF imaging is useful for the diagnosis and monitoring of many retinal diseases, including AMD, inherited retinal diseases, tumors, and inflammatory retinal conditions. Advances in FAF imaging include spectral analysis and fluorescence lifetime analysis. Fundus autofluorescence (FAF) is a noninvasive imaging technique that visualizes the naturally occurring fluorescence of structures in the outer retina and beyond. Autofluorescence occurs when endogenous fluorophores are excited by light of a suitable wavelength and then re-emitted with lower energy.1 This article offers a brief guideline for understanding how FAF works and its use in diagnosing and managing various retinal diseases. HOW IT WORKS The main anatomical sources of autofluorescence are the photoreceptors and the retinal pigment epithelium (RPE). In particular, the RPE is the main contributor to short-wavelength FAF through lipofuscin and melanolipofuscin organelles, and to near-infrared (NIR) FAF through melanin-containing organelles, such as melanosomes. Under normal physiological conditions, bisretinoids are formed as byproducts of the visual cycle and gradually accumulate, together with lipids, within RPE lysosomes, forming lipofuscin and melanolipofuscin granules. These granules represent the dominant source of the FAF signal. The number, size, and spatial distribution of these granules within the RPE cells largely determine the FAF pattern observed with short-wavelength excitation (Figure 1).