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목적 : To analyze mean corneal powers and astigmatisms on anterior, posterior, and total cornea in patients with keratoconus as calculated according to various keratometric measurements using a Scheimpflug camera.
방법 : We examined the left eyes of 64 patients (41 males and 23 females; mean age 29.94 ± 6.63 years) with keratoconus. We measured simulated K (Sim-K), posterior K, true net power (TNP), equivalent K readings (EKR), and four types of total corneal refractive powers (TCRP). We then used the obtained values to analyze flat K, steep K, mean K, and corneal astigmatism. EKR and TCRP were measured at 2.0~5.0 mm.
결과 : Mean K from Sim K, posterior K, and TNP were 49.12 ± 3.99, -7.39 ± 0.79, and 47.78 ± 4.09 diopters, respectively. Corneal astigmatism as measured by EKR increased with measurement zone (p = 0.00). For TCRP centered on the pupil, mean K tended to decrease with measurement area (all p < 0.01). While, both mean K and astigmatism measured using TCRP centered on the apex decreased with measurement area (all p = 0.00). Dioptric power centered on the apex were greater than those centered on the pupil for mean K values calculated using TCRP (all p = 0.00).
결론 : Corneal powers and astigmatisms on total cornea with keratoconus vary depending on calculating methods and measurement areas.
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