Early Changes In Eyes Of Keratoconus Patients

To identify variables best suited to detecting keratoconus beforemanifestation of ectatic changes and showing disease progression in the very earlystage

National Centre of Ophthalmology named after acad. Zarifa Aliyeva, Baku, Azerbaijan

27 patients with diagnosed unilateral keratoconus were followed up for theirfellow eye, which had not yet shown any ectactic changes, to determine initial changeindicators towards keratoconus disease. Variables were compared to 50 normal eyeswithout any known disease. A following receiver-operating-characteristic (ROC)analysis was performed to reveal the variables best used to discriminate healthy eyesfrom early ectatic eyes.

Calculated mean difference of the cylinder for TCRP (total corneal refractivepower) was only 0.07D ± 0.32 for CA (anterior astigmatism) = 0.12D ± 0.28, CB(posterior astigmatism) = 0.02D ± 0.1. (ROC) revealed the index of height decentration(IHD) with an area under the curve of 0.788 ± 0.054 as the most suitable todifferentiate between healthy and afflicted eyes, followed by the index of verticalasymmetry (IVA) = 0.772 ± 0.057 and keratoconus index (KI) = 0.743 ± 0.062. Withprogression of the eyes into early ectactic stages the ROC, however, showed thehighest area under the curve for D-index = 0.876 ± 0.039, followed by IHD = 0.855 ±0.046 and IVA = 0.842 ± 0.046.

Early stages of keratoconus are hard to diagnose, best results can beachieved by using IHD and IVA. As the disease progresses, D-index is better suited todiagnose an ectasia. Astigmatism, keratometry and pachymetry barely change in theearly stages so these values are not as fitting as corneal elevation parameters for earlydiagnosis.