Analysis promising for keratectasia

Sep 01, 2011

Diagnostic platform combines anterior surface topography, corneal tomography data

An analysis combining information from anterior Placido topography and corneal tomography obtained using a proprietary corneal imaging diagnostic platform (Orbscan II, Bausch + Lomb) has shown high sensitivity and specificity for discriminating between Placido negative eyes with forme fruste keratoconus (FFKC) and normal controls, and shows promise as a clinically useful tool for early diagnosis of keratectasia, said Dr Damien Gatinel, PhD.

"Our investigation shows that in eyes where there is no suspicion of keratoconus based on objective analysis of the anterior topography, evaluation of corneal tomography data may sometimes reveal an underlying ectatic condition," he added.

"Answering the question of what technique is superior for early detection of keratectasiasusceptible corneas requires welldesigned investigations. These must use a pertinent clinical model and appropriate statistical methods," Dr Gatinel said.

"These studies must include corneas with known keratectasia susceptibility, and to achieve maximum specificity and sensitivity, they must use discriminant analysis that evaluates the method's performance in separating the study groups and so minimizes false negatives and false positives," he explained.

Borrowing from Dr Stephen D. Klyce, PhD, who stated that the fellow eye of a patient with unilateral keratoconus should be considered as having FFKC, Dr Gatinel suggested that the fellow 'normal' represents the perfect false negative model for discriminant analysis studies.

"As Dr Klyce said, although the FFKC eye has no clinical findings of keratoconus and is Placido negative, it has genetic susceptibility to keratoconus and is considered to have subclinical keratoconus," he said.

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