Abandon Kmax in favour of newer measures
Early detection will allow early treatment, preventing irreversible vision loss
Howard Larkin
Published: Saturday, September 14, 2019
[caption id="attachment_16526" align="alignleft" width="1024"]
Michael W Belin[/caption]
MODERN corneal tomography measurements, including anterior and posterior elevation and pachymetric data, can help diagnose and detect progression in keratoconus earlier and more reliably than can changes in maximum anterior sagittal curvature (Kmax), Michael W Belin MD told a joint session of EuCornea and The Cornea Society.
Kmax problems include poor correlation with corrected distance visual acuity as well as low sensitivity and specificity, making it unreliable in identifying keratoconus, noted Dr Belin, University of Arizona, Tucson, USA.
More importantly, by the time ectasia progresses enough to significantly alter Kmax, significant vision loss has occurred in most cases, Dr Belin said. Measures he has developed based on anterior and posterior corneal curvature, corneal thickness and distance visual acuity are much more sensitive and specific. He presented several cases of posterior cornea steepening with no change in anterior curvature in both early and advanced disease.
Early detection will allow early treatment, preventing irreversible vision loss, Dr Belin said. He advocates abandoning Kmax for more predictive measures. “We don’t treat glaucoma only after patients have visual field loss, and we should be doing the same with keratoconus,” he concluded.
Michael W Belin[/caption]
MODERN corneal tomography measurements, including anterior and posterior elevation and pachymetric data, can help diagnose and detect progression in keratoconus earlier and more reliably than can changes in maximum anterior sagittal curvature (Kmax), Michael W Belin MD told a joint session of EuCornea and The Cornea Society.
Kmax problems include poor correlation with corrected distance visual acuity as well as low sensitivity and specificity, making it unreliable in identifying keratoconus, noted Dr Belin, University of Arizona, Tucson, USA.
More importantly, by the time ectasia progresses enough to significantly alter Kmax, significant vision loss has occurred in most cases, Dr Belin said. Measures he has developed based on anterior and posterior corneal curvature, corneal thickness and distance visual acuity are much more sensitive and specific. He presented several cases of posterior cornea steepening with no change in anterior curvature in both early and advanced disease.
Early detection will allow early treatment, preventing irreversible vision loss, Dr Belin said. He advocates abandoning Kmax for more predictive measures. “We don’t treat glaucoma only after patients have visual field loss, and we should be doing the same with keratoconus,” he concluded.
Tags: keratoconus, kmax
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