Multimodal diagnostics for keratoconus and ectatic corneal diseases: a paradigm shift

Abstract

Different diagnostic approaches for ectatic corneal diseases (ECD) include screening, diagnosis confirmation, classification of the ECD type, severity staging, prognostic evaluation, and clinical follow-up. The comprehensive assessment must start with a directed clinical history. However, multimodal imaging tools, including Placido-disk topography, Scheimpflug three-dimensional (3D) tomography, corneal biomechanical evaluations, and layered (or segmental) tomography with epithelial thickness by optical coherence tomography (OCT), or digital very high-frequency ultrasound (dVHF-US) serve as fundamental complementary exams for measuring different characteristics of the cornea. Also, ocular wavefront analysis, axial length measurements, corneal specular or confocal microscopy, and genetic or molecular biology tests are relevant for clinical decisions. Artificial intelligence enhances interpretation and enables combining such a plethora of data, boosting accuracy and facilitating clinical decisions. The applications of diagnostic information for individualized treatments became relevant concerning the therapeutic refractive procedures that emerged as alternatives to keratoplasty. The first paradigm shift concerns the surgical management of patients with ECD with different techniques, such as crosslinking and intrastromal corneal ring segments. A second paradigm shift involved the quest for identifying patients at higher risk of progressive iatrogenic ectasia after elective refractive corrections on the cornea. Beyond augmenting the sensitivity to detect very mild (subclinical or fruste) forms of ECD, ectasia risk assessment evolved to characterize the inherent susceptibility for ectasia development and progression. Furthermore, ectasia risk is also related to environmental factors, including eye rubbing and the relational impact of the surgical procedure on the cornea.

Pressure-Induced Stromal Keratopathy after Surface Ablation Surgery

“…Scheimpflug imaging using rotating corneal tomography and ultra-high-speed biomechanical assessments provides valuable data for accurate diagnosis and treatment planning. Several studies have already demonstrated their significance in detecting an increased susceptibility to ectasia [14][15][16]. This case underscores the importance of investigating ocular biomechanics for precise IOP measurement, offering insights into the actual effects of IOP fluctuations on corneal biomechanical measurements.…”

Assessment of Preoperative Risk Factors for Post-LASIK Ectasia Development [Response to Letter]

“…We agree with Navarro-Naranjo et al in their letter that multimodal diagnostics, beyond front surface topography and 3-D tomography, is essential to augment the safety and efficiency of refractive surgery. 4 Corneal biomechanical assessment, integrated with tomography with artificial intelligence, aims to characterize the corneal predisposition or susceptibility to biomechanical decompensation. 4,5 This concept goes beyond, but not over, the detection of mild or subclinical (fruste) cases of keratoconus.…”

“…4 Corneal biomechanical assessment, integrated with tomography with artificial intelligence, aims to characterize the corneal predisposition or susceptibility to biomechanical decompensation. 4,5 This concept goes beyond, but not over, the detection of mild or subclinical (fruste) cases of keratoconus. The BrAIN (Brazilian Artificial Intelligence Networking in Medicine) ectasia software combines with AI the intrinsic predisposition and the extrinsic impact of the corneal procedure to objectively characterize ectasia risk (https://brain.med.br/).…”

Keratoconus and Corneal Ectasia with Relatively Low Keratometry

“…Identifying early-stage and subclinical ectatic corneal conditions has become increasingly important, as such cases are particularly vulnerable to post-LVC iatrogenic ectasia. The current concept for assessing ectasia risk before refractive surgery is to consider data beyond (not over) the corneal anterior surface with a multimodal approach to characterize ectasia susceptibility [ 17 , 18 ].…”