Advances in the diagnosis and treatment of keratoconus

Abstract

Keratoconus had traditionally been considered a rare disease at a time when the imaging technology was inept in detecting subtle manifestations, resulting in more severe disease at presentation. The increased demand for refractive surgery in recent years also made it essential to more effectively detect keratoconus before attempting any ablative procedure. Consequently, the armamentarium of tools that can be used to diagnose and treat keratoconus has significantly expanded. The advances in imaging technology have allowed clinicians and researchers alike to visualize the cornea layer by layer looking for any early changes that might be indicative of keratoconus. In addition to the conventional geometrical evaluation, efforts are also underway to enable spatially resolved corneal biomechanical evaluation. Artificial intelligence has been exploited in a multitude of ways to enhance diagnostic efficiency and to guide treatment. As for treatment, corneal cross-linking treatment remains the mainstay preventive approach, yet the current main focus of research is on increasing oxygen availability and developing new strategies to improve riboflavin permeability during the procedure. Some new combined protocols are being proposed to simultaneously halt keratoconus progression and correct refractive error. Bowman layer transplantation and additive keratoplasty are newly emerging alternatives to conventional keratoplasty techniques that are used in keratoconus surgery. Advances in tissue engineering and regenerative therapy might bring new perspectives for treatment at the cellular level and hence obviate the need for invasive surgeries. In this review, we describe the advances in the diagnosis and treatment of keratoconus primarily focusing on newly emerging approaches and strategies.

Oxygen in Corneal Collagen Crosslinking to Treat Keratoconus: A Systematic Review and Meta-Analysis

“…The epithelium is a barrier and metabolically consumes oxygen so it has been suggested oxygen increases the rate of diffusion to the stroma. 36 Oxygen is an important reagent in the lysyl oxidase pathway to produce free radicals to catalyze crosslinks between corneal fibers. 19 Although CXL can occur in aerobic (type 1 pathway) and anaerobic (type II pathway) environments, the aerobic pathway results in more oxygen radicals through reoxidizing riboflavin to its original form.…”

Analysis of the correlation between biomechanical properties and corneal densitometry in myopic eyes

“…Previous researcher [9] thought that changes in the corneal mechanical properties preceded any structural lesions.…”

A Review of Corneal Blindness: Causes and Management

“…The early detection of keratoconus can be done by more frequent monitoring of the disease progression and performing the indicated interventions at the time, leading to improved patient outcomes so that the use of transplantation of cornea is reduced to a significant amount [19]. The advances for the diagnosis are the corneal biomechanics, various biomarkers like tear inflammatory cytokine or levels of matrix metalloproteinases in the tear immunoglobulin A or by using artificial intelligence [28].…”

“…One of the more unknown molecules isolated from the Streptoverticillium sp., named transglutaminase, does not need photoactivation, which makes the cornea stiffer without causing much damage to the underlying layers of the cornea. The others include numerous keratoplasty procedures, transplantation of the Bowman's layer, additive keratoplasty, and cellular therapies [28]. Keratoconus causes the fragmentation of the Bowman's layer in the earliest phase of the disease [29].…”

“…The additive keratoplasty helps to increase the thickness of the cornea along with biomechanical stability. To avoid immune rejection, an approach towards tissue engineering has been preferred, which enabled better outcomes in the case of visual acuity and in terms of biomechanical effects [28]. Diagnosis of non-infectious uveitis is based on clinical symptoms and the association with systemic diseases [33].…”