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Lorena Lam Franco, Paloma Lopez, Julio C Hernandez, Jorge E Valdez; Evaluation of topographic indices in Hispanic patients with Keratoconus and Keratoconus suspects. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):1631.
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© ARVO (1962-2015); The Authors (2016-present)
To describe the demographic characteristics and topographic patterns of Hispanic patients with keratoconus (KC) and KC suspects.
Retrospective, observational case series. A random sample of 550 records from patients referred to the Cornea and Refractive Surgery Service from the Institute of Ophthalmology at the Zambrano Hellion Medical Center from January 2008 to November 2014. Patients diagnosed with KC or KC suspect were included for analysis. Corneal topography was performed using the Tomey Topographic Modeling System (TMS), as well as ultrasonic pachymetry to measure central corneal thickness (CCT). Analyzed topographic indices were Surface Asymmetry Index, Opposite Sector Index, Irregular Astigmatism Index, Differential Sector Index, Center/Surround Index, Keratoconus Prediction Index, and Standard Deviation of corneal Power. Posteriorly eyes were grouped into KC and KC suspect.
From the entire study sample, a total of 33 patients (62 eyes) with KC/KC suspect were diagnosed. 66.7% had KC in both eyes, 21.2% KC + KC suspect, and 12.1% KC suspect both eyes. 47 eyes (4.3%) were diagnosed with KC and 15 (1.4%) as KC suspects. 20 (60.6%) were male and 13 (39.5%) female. The mean age at diagnosis was 32.8±13.22 years (range 17-64). Mean age was significantly lower in patients with KC compared to KC suspect (29.7±9.2 and 53.3±15.3 respectively, P<0.001). The most common cone location was central (31.9%) and 46.8% of the eyes were stage 1 in the Amsler Krumeich Classification. Eyes in the KC group had higher maximum keratometry (55.11±4.9D) and mean keratometry (48.0±7.8D), but lower CCT (498.8±43.11µm) than KC suspects (48.49±3.27D, 45.48±1.78D, and 546.4±17.07µm respectively) (P<0.001, P=0.23 and P=0.01). The means of the seven topographic indices were found to be significantly higher in eyes in the KC group than the KC suspect group (P<0.001).
We found an important prevalence of KC and KC suspects (4% and 1%) among our population, with a significant difference of topographic indices, age, maximum keratometry and CCT between KC suspects and KC patients.
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