A New Era for Keratoconus Diagnostics

The in-depth study of keratoconus and ectatic corneal diseases is undergoing a major paradigm shift, moving from late recognition of advanced disease toward earlier detection, prevention, and individualised care. According to Renato Ambrósio Jr MD, PhD, this shift depends on multimodal diagnostics, artificial intelligence, and a clearer distinction between corneal ectasia diagnostics (CED) and ectasia risk assessment (ERA).

Professor Ambrósio delivered this message during the Lorenzo il Magnifico Medal Lecture at the 3rd World Keratoconus Congress. The honour was particularly fitting, as Lorenzo il Magnifico became a symbol of Renaissance patronage and cultural integration in Florence. For Prof Ambrósio, the new diagnostic era in keratoconus also requires integration of technology, clinical reasoning, education, and a patient-centred purpose.¹

In the past, patients with keratoconus were often diagnosed only when the disease was already advanced, when keratoplasty was the primary and only surgical option. Today, improved contact lens rehabilitation, cross-linking, intrastromal corneal ring segments, phakic IOLs, and refractive therapeutic strategies have changed the timing and meaning of diagnosis. “A paradigm shift is when new evidence changes how the field sees, thinks, and decides,” Prof Ambrósio said. “It changes the meaning of the data, not just the data.”

It is for this reason he places strong emphasis on the ‘why’ of multimodal diagnostics. CED and ERA are complementary, but they are not the same. CED is diagnosis-oriented: it includes population screening, diagnosis confirmation, classification, staging, prognosis, individualised management, and clinical follow-up. ERA is risk-oriented: it goes beyond detecting early keratoconus to characterise the cornea’s susceptibility to biomechanical decompensation and ectasia progression, particularly when elective refractive surgery or laser vision correction procedures are considered.

This distinction matters because ‘normal topography’ is not equivalent to ‘no susceptibility.’ Placido disk topography remains important, but it is only one surface-based expression of a deeper structural and biomechanical reality. Multimodal evaluation integrates directed clinical history, slit-lamp examination, Placido topography, Scheimpflug tomography, epithelial or layered tomography with OCT, corneal biomechanics, ocular wavefront, biometry, and, in the future, genetic and molecular data.

The conceptual framework also connects with McGhee’s two-hit hypothesis, which proposes keratoconus and ectatic progression result from the interaction between intrinsic susceptibility (the first hit) and extrinsic influences (the second hit).² Prof Ambrósio suggested that this concept should increasingly be recognised as a theory, considering the accumulated clinical evidence and the biomechanical cycle of corneal decompensation described by Roberts and Dupps.³ In practical terms, ectasia should be understood as a dynamic interaction between corneal resistance and environmental or surgical impact.

Eye rubbing is one of the most important preventable extrinsic factors. As Prof Damien Gatinel has emphasised, eye rubbing can be understood as a sine qua non factor for ectasia progression.⁴ Prof Ambrósio suggested refining this concept: eye rubbing and ocular trauma may be considered sine qua non extrinsic triggers for ectasia progression because they can aggravate keratoconus or, in selected situations, induce secondary ectasia. This distinction is important because aggravating keratoconus or causing secondary ectasia is not the same as initiating primary keratoconus. Even if the role of eye rubbing in disease initiation remains debated, patient education about eye rubbing, allergy, inflammation, and ocular trauma is central to prevention and follow-up.

In refractive surgery screening, the field has evolved from classical structural parameters toward more relational and individualised measures.⁵ Residual stromal bed (RSB) remains a classical parameter, while percent tissue altered (PTA) introduced by Santhiago helped express the proportion of tissue affected by LASIK.^6,7 More recently, relational tissue altered (RTA) was developed by Aydano P Machado using machine learning to provide an objective, data-driven metric of the structural impact induced by laser vision correction.⁸ RTA is incorporated into BEES (the BrAIN Enhanced Ectasia Software) as part of a broader strategy to integrate surgical impact with intrinsic susceptibility to ectasia.

Prof Ambrósio stressed that RTA should not be interpreted as a standalone predictor of ectasia among laser vision correction candidates. Its value lies in quantifying the procedural impact on the cornea. The stronger clinical model emerges when surgical impact, as measured by metrics such as RTA, is combined with intrinsic susceptibility, characterised by tomography, biomechanics, epithelial mapping, and other multimodal parameters.

AI is, therefore, not simply a new diagnostic label.⁹ Its value lies in helping clinicians interpret large, complex data sets while preserving clinical judgement. In Prof Ambrósio’s framework (AI²), applied artificial intelligence provides the ‘how,’ while clinical purpose, what he calls “applied ancient intelligence,” provides the ‘why.’² AI should support the physician’s discernment, not replace it.

Enhanced ectasia risk assessment represents the real paradigm shift in corneal diagnostics. It moves the field beyond, but not over, detecting early keratoconus—beyond topography and even tomography alone—and toward a multimodal understanding of ectasia susceptibility.

“What this field needs is to continue evolving through science,” Prof Ambrósio concluded. “We must go beyond detecting early keratoconus to characterise ectasia susceptibility, beyond topography and tomography toward multimodal diagnosis, and beyond artificial intelligence alone toward careful, patient-centred clinical judgement.”

Prof Ambrósio spoke at the 3rd World Keratoconus Congress 2026 in Florence, Italy.

Renato Ambrósio Jr MD, PhD, FWCRS, PCEO is Adjunct Professor of Ophthalmology at the Federal University of the State of Rio de Janeiro, Affiliated Professor at the Federal University of São Paulo, Refractive Surgery Director of Rio Vision Hospital in Rio de Janeiro, and CEO of BrAIN, Brazilian Artificial Intelligence Networking in Medicine. dr.renatoambrosio@gmail.com

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