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Descriptive study of topographic patterns in clinically diagnosed keratoconus
Author(s) -
JIMENEZ DEL RIO B,
PEREZ GARCIA D,
CASAS P,
CRUZ N,
RAMIRO MILLAN P,
DEL BUEY MA,
CRISTOBAL BESCOS JA
Publication year - 2010
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2010.334.x
Subject(s) - keratoconus , medicine , ophthalmology , corneal topography , elevation (ballistics) , apex (geometry) , cornea , anatomy , mathematics , geometry
Purpose This study was undertaken with the objective of responding to some questions: how are our patients´s keratoconus? and could we establish unified topographic patterns to describe them? Methods Descriptive analysis of different parameters evaluated by Orbscan corneal topography system (BFS, RCA/RCP, anterior and posterior elevation, Simk, mean pwr, thinnest) and biomechanical indices measured with Ocular Response Analyzer (CRF and CH) as well as topographic patterns that can be found in the clinical keratoconus diagnosed between 2006 and 2009 in ophthalmology service at Hospital Clinico "Lozano Blesa" in Zaragoza. Results We have studied 40 eyes of 24 patients diagnosed with keratoconus.Subclinical keratoconus and those who had received treatment,either rigid contact lenses or implanted intracorneal ring segments were previously excluded. The average age of patients was 33.7+/‐11.1 years. Quantitative topographic descriptors were: BFS = 55.99+/‐3.35 D; RCA/RCP = 1.25+/‐0.04, anterior surface elevation = 48.08+/‐26.66 µ; back surface elevation = 107.18+/‐43.11 µ; simk = ‐5.4+/‐2.6 D, mean pwr = 48.5+/‐3.7 D; thinnest = 423+/‐67 µ; biomechanical values: CRF = 6.9+/‐1.7 and CH = 7.8+/‐1.4. Four topographic patterns are also described depending on the situation of the apex of the cone: 30% central, 35% lower, 30% inferior temporal, 5% inferior nasal. Conclusion There is great morphological variation in keratoconus, it is therefore important to unify criteria for classification. The apex location criteria allows us to make a simple classification of keratoconus and is useful for planning intracorneal ring segments implantation.