Details

Autor(en) / Beteiligte

• Ueno, Yuta
• Hiraoka, Takahiro
• Beheregaray, Simone
• Miyazaki, Maki
• Ito, Mutsuko
• Oshika, Tetsuro

Titel

Age-related changes in anterior, posterior, and total corneal astigmatism

Ist Teil von

• Journal of refractive surgery (1995), 2014-03, Vol.30 (3), p.192

Ort / Verlag

United States

Erscheinungsjahr

2014

Quelle

MEDLINE

Beschreibungen/Notizen

• To evaluate age-related changes in anterior, posterior, and total corneal astigmatism by comparing simulated keratometric astigmatism to total corneal astigmatism. Corneal topography of the anterior and posterior surfaces was evaluated using three-dimensional optical coherence tomography in 419 patients with normal eyes (218 men and 201 women) with ages ranging from 8 to 93 years (mean ± standard deviation: 49.5 ± 23.1 years). Keratometric astigmatism was calculated using the keratometric index (1.3375) and radius of the anterior corneal curvature; anterior and posterior corneal curvature measurements were used to calculate total corneal astigmatism. The keratometric and total astigmatism were 1.08 ± 0.71 diopters (D) and 1.03 ± 0.69 D, respectively. Vector analysis revealed a mean difference between keratometric and total astigmatism of 0.24 ± 0.09 D, which showed a significant correlation to age (P < .0001). In eyes with with-the-rule astigmatism, keratometric astigmatism overestimated total astigmatism. In eyes with against-the-rule astigmatism, keratometric astigmatism underestimated total astigmatism. The anterior corneal surface shifts from with-the-rule to against-the-rule astigmatism with aging, whereas the posterior corneal surface remains as against-the-rule astigmatism in most cases. The variation in the anterior astigmatism is the most important factor contributing to this change. Total corneal astigmatism is a better predictor than keratometric astigmatism for selecting toric intraocular lenses.