Determination of normal range of corneal higher-order aberrations and the application to diagnose keratoconus

Session Details

Session Title: Moderated Poster Session: New and Interesting

Venue: Poster Village: Pod 1

First Author: : T.Hiraoka JAPAN

Co Author(s): :    G. Kiuchi   Y. Ueno   T. Oshika                 

Abstract Details

Purpose:

Corneal aberrometry is a valuable tool for evaluating the optical quality of the cornea in eyes with various pathologies, and it has been widely applied in clinical practice. Recently, it became possible to measure wavefront aberrations of posterior cornea as well as anterior cornea. However, the normal ranges have not been determined. In this study, we tried to determine normal range of corneal higher-order aberrations (HOAs) based on large population data, and compared the obtained results with HOAs of keratoconic eyes.

Setting:

University of Tsukuba Hospital, Ibaraki, Japan

Methods:

We examined 844 eyes of 422 subjects without corneal diseases. All eyes were measured by anterior segment optical coherence tomography (OCT) (CASIA SS1000, Tomey Co., Japan), and HOAs of the anterior, posterior, and whole corneas were calculated based on the height data. These calculations were performed for 4- and 6-mm pupils. The normal range of corneal HOAs was defined as the mean ± 2×standard deviation. In addition, corneal HOAs were evaluated in 49 eyes with clinically diagnosed keratoconus, and performance of discrimination between normal and keratoconic eyes was assessed by calculating the area under the receiver operating characteristic curve (AUROC).

Results:

The normal ranges of anterior cornea were 0.05-0.35 (4mm) and 0.13-0.79 µm (6mm) for coma-like, 0.06-0.36 and 0.14-0.62 µm for spherical-like, and 0.12-0.48 and 0.27-0.94 µm for total HOAs, respectively. Those of posterior cornea were 0-0.07 and 0-0.15 µm for coma-like, 0.01-0.06 and 0.07-0.17 µm for spherical-like, and 0.02-0.09 and 0.08-0.21 µm for total HOAs, respectively. Those of whole cornea were 0.05-0.34 and 0.12-0.74 µm for coma-like, 0.05-0.34 and 0.14-0.58 µm for spherical-like, and 0.11-0.45 and 0.25-0.88 µm for total HOAs, respectively. As for the AUROC, coma-like and total HOAs of posterior cornea showed the highest value (1.00).

Conclusions:

We proposed the normal ranges of corneal HOAs which were evaluated by anterior segment OCT. We also elucidated that HOAs of posterior cornea had higher discrimination performance between normal and keratoconic eyes than those of anterior or whole cornea, showing a more sensitive index of posterior HOAs for the diagnosis of keratoconus. Evaluation of corneal HOAs may provide useful information for improving the diagnostic accuracy of keratoconus.

Financial Disclosure:

None