Posters

Corneal topographic analysis after penetrating keratoplasty in patients with keratoconus using swept-source optical coherence tomography

Poster Details

First Author: R.Toda JAPAN

Co Author(s):    N. Maeda   M. Fuchihata   K. Hayashi   S. Koh   Y. Kiuchi   K. Nishida     

Abstract Details

Purpose:

It is difficult for the conventional corneal topographer to perform topographic analysis after penetrating keratoplasty (PK) beyond the host-graft junction because visible light makes it difficult to detect corneal contour because of the scarring and irregularity of the cornea. We performed corneal topographic analysis up to the peripheral cornea using swept-source optical coherence tomography (OCT) in patients following PK for keratoconus.

Setting:

Retrospective case series/Osaka University Hospital, Osaka, Japan

Methods:

A total of 38 eyes following PK for keratoconus (suture-in: 21 eyes, suture-out: 17 eyes) were included in the study. Fifty-four normal eyes served as the control group. For these subjects, the corneal shape was measured with a swept-source OCT (SS-1000, Tomey Corp., Japan). The axial power map was classified into four categories based on two central patterns: cooler or warmer bow-tie and two peripheral patterns: single-ring or a double-ring pattern. Topographic indices including the average keratometric power, cylinder power, total higher-order aberrations, spherical aberration (SA), and coma aberration for 6 mm diameter were compared.

Results:

The axial power map determined that 76% eyes in the suture-in group had a warmer bow-tie pattern, whereas 94% eyes in the suture-out group had the cooler bow-tie pattern at the center (Chi-squared test); 81% eyes in the suture-in group had the double-ring sign, although 100% eyes in the suture-out groups had single-ring sign in the periphery (Chi-squared test). Mean SA in the suture-in, suture-out, and control groups were −0.31 ± 0.81, 0.97 ± 0.60, and 0.21 ± 0.12, respectively. Mean SA in the suture-out group was significantly higher than that in the suture-in group (Steel–Dwass test).

Conclusions:

The central corneal shape in the suture-in group following PK for keratoconus showed a warmer bow-tie with negative SA, suggesting a more prolate shape than that in the control because of the depression at the host-graft junction possibly associated with the compression of tissue, and this may also create the double-ring pattern in the periphery. On the other hand, the oblate shape shown by the flat bow-tie and a higher SA in the suture-out group may be caused by the anterior protrusion associated with the weakening of the host-graft junction.

Financial Disclosure:

NONE