Identification of canning lit-Beam Topographic Parameter Important in Ditinguihing Normal from Keratoconic Corneal Morphologic Feature Original Reearch Article

Purpoe To identify morphologic parameter obtained uing canning lit-beam topography that help ditinguih normal from keratoconic corneal morphologic feature. Deign Obervational, retropective, cro-ectional tudy. Method Thi retropective review examined 207 normal eye of patient undergoing an initial conultation for primary refractive urgery and 42 eye with clinical keratoconu (KCN). The following parameter were examined and compared between the two group: atigmatim, central corneal power, irregularity indice at 3 mm (II3) and 5 mm (II5), maximal poterior elevation (MPE) magnitude and location, thinnet optical pachymetry (TOP) magnitude and location, anterior elevation bet-fit phere (ABF), poterior elevation bet-fit phere (PBF), the ratio of ABF to PBF, the difference between average inferior and average uperior K value at 3 mm and 5 mm in both keratometric (I− K3 and I− K5) and tangential (I− T3 and I− T5) topographic map, and kewed radial axi at 3 mm (RAX3) and 5 mm (RAX5) of the keratometric topography map. Reult The II3, II5, MPE magnitude, TOP magnitude, ABF, PBF, ABF-to-PBF ratio, I− K at both 3 mm and 5 mm, I− T at both 3 and 5 mm, and RAX at 3 mm and 5 mm value were ignificantly different among the two group (P < .001). The leat-correlated parameter were RAX3, TOP magnitude, and II3 in the KCN group and I− K3, amount of atigmatim and MPE magnitude in the normal group. Concluion Parameter obtained uing canning lit-beam topography may allow improved differentiation of keratoconic from normal corneal hape, epecially when the poorly correlated intragroup parameter are ued.