Posters

Anterior and posterior corneal stroma elasticity after corneal collagen cross-linking treatment assessed using atomic force microscopy

Poster Details

First Author: V.Diakonis GREECE

Co Author(s):    V. Kankariya   J. Dias   S. Yoo   N. Ziebarth   G. Kymionis  

Abstract Details

Purpose:

To assess anterior and posterior corneal stromal elasticity after corneal collagen cross linking (CXL) treatment in human cadaver eyes using Atomic Force Microscopy (AFM).

Setting:

Bascom Palmer Eye Institute, Miami, Florida, USA

Methods:

Twenty four human cadaver eyes (12 pairs) were included in this study and divided into 2 groups (6 pairs per group). In both groups, the left eye (OS) served as a control (no CXL treatment was performed) and the right eye (OD) underwent CXL treatment (30 minutes of riboflavin pretreatment followed by 30 minutes of exposure to 3mW/cm2 of ultraviolet light). In group 1, the anterior stroma was exposed by manual delamination of approximately 50 microns of the corneal stroma including Bowman's membrane. In group 2, the posterior stroma was exposed by delamination of the anterior 50% of the corneal stroma including Bowman's membrane. Delamination was performed after crosslinking treatment in the case of the treated eyes. In all eyes, the stromal elasticity was quantified using AFM through nanoindentation.

Results:

Young's modulus of elasticity for the anterior cornea (group 1) was 245.9 +/- 209.1kPa (range: 82.3 - 530.8 kPa) for the untreated control eyes, and 467.8 +/- 373.2kPa (range: 157.4 - 1126 kPa) for the CXL treated eyes. Young's modulus for the posterior cornea (group 2) was 100.2 +/- 61.9kPa (range: 28.1 - 162.6 kPa) for the untreated control eyes and 66.0 +/- 31.8kPa (range: 31.3 - 101.7 kPa) for the CXL treated eyes. Young's modulus of the anterior stroma significantly increased after CXL treatment (p=0.024), whereas the posterior stroma did not demonstrate a significant difference in Young's modulus after CXL treatment (p=0.170). The anterior stroma was significantly stiffer than the posterior stroma after CXL treatment (p=0.023).

Conclusions:

Stiffness of the anterior corneal stroma after CXL treatment seems to increase significantly, while the posterior stroma does not seem to be affected by CXL. FINANCIAL INTEREST: NONE