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Angela Zhu, Eva-Maria Lackner, Jennifer Elisseeff, Albert S Jun; Development of a Porcine Eye Model to Assess Application of a Novel Corneal Shaping Device during Corneal Collagen Cross-Linking (CXL). Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):1140.
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© ARVO (1962-2015); The Authors (2016-present)
Corneal collagen cross-linking (CXL) has great potential in delaying progression of corneal ectactic disorders, but CXL alone cannot substantially improve corneal shape abnormalities. We designed a novel corneal shaping device to be physically applied during CXL and developed an ex vivo porcine eye model to show that our device prototype used in conjunction with CXL can alter corneal curvature to a greater extent than with CXL alone.
A prototype of the corneal shaping device was made with flat, rigid, UV-transmissible material (Figure 1). Fresh enucleated porcine eyes were de-epithelialized mechanically and perfused at 20 mmHg. Pre-experimental corneal curvature (K) was measured using a portable auto-keratometer (Nidek KM-500), and Anterior Segment Optical Coherence Tomography (AS-OCT) imaging was performed. Following the conventional CXL protocol, all eyes were pre-treated with 0.01% riboflavin every 2 min. for 30 min. Each experiment consisted of 6 treatment groups in duplicate: A) no device + no CXL, B) 30 min. device + no CXL, C) no device + 10 min. CXL, D) 10 min. device + CXL, E) no device + 30 min. CXL, F) 30 min. device + CXL. Post-experimental K values and AS-OCT images were acquired. Corneal thickness and demarcation line measurements were obtained using Visante AS-OCT analysis software. The experiment was repeated six times (n = 12 in each group). Two-tailed Student’s t-test was used for statistical analysis.
There was a significant decrease in corneal curvature after 30 min. CXL between group F (ΔKm = -1.54 ±0.90 D) and group E (ΔKm = +0.34 ± 0.53 D, p < 0.001) or group B (ΔKm = +0.69 ± 1.02 D, p < 0.001). The demarcation line depth was greater in group F than group D (p < 0.05). There was also less change in corneal thickness in groups D & F than in the control groups (p < 0.05).
Application of our novel corneal shaping device during the conventional CXL protocol can significantly decrease corneal curvature compared to controls. AS-OCT imaging showed comparable extent of UV cross-linking (demarcation line depth) in eyes treated ± device. This demonstrates that our novel device used during CXL may further benefit patients with corneal ectactic disorders by promoting corneal strengthening and refractive correction.
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