Stiffening of Rabbit Sclera by Bacteriochlorophyll Derivative WST11 Using Near Infrared Light

Saturday, April 26, 2014: 4:04 PM
Room 150 (Boston Convention and Exhibition Center)
Arie L. Marcovich, MD, Kaplan Medical Center and Weizmann Institute of Science, Rehovot, Israel
Alexander Brandis, PhD, Weizmann Institute of Science, Rehovot, Israel
Iddo Pinkas, PhD, Weizmann Institute of Science, Rehovot, Israel
Ilan Feine, PhD, weizmann institute of science, kfar urya, Israel
Hanoch D. Wagner, Weizmann Institute of Science, Rehovot, Israel
Yoram Salomon, PhD, Weizmann Institute of Science, Rehovot, Israel
Avigdor J. Scherz, PhD, Weizmann Institute, Rehovot, Israel

Narrative Responses:

Purpose
To evaluate the efficacy of photochemical stiffening of the sclera by WST11 and near infrared (NIR) on enucleated rabbit eyes for the treatment of progressive myopia.

Methods
Four rabbit eyes were enucleated post mortem and treated topically with WST11 2.5 mg/ml for 30 minutes on the superior or inferior sclera, followed by external illumination with NIR at 10mW/cm2 for 30 minutes by a diode laser at 755nm. The opposite side of the sclera served as control. After the treatment, the eye was dissected to superior and inferior halves. Scleral equatorial strips, 4±0.2mm in width, were cut with a self-constructed double-blade cutter. Stress-strain measurements were performed using a biomaterial tester.

Results
After WST11/NIR the ultimate stress increased by 174% from 2.77±0.99 MPa in the non-treated sclera to 7.6±0.99 MPa after treatment. Young’s modulus increased by 200% from 15.2 ±7.5 MPa in the non-treated control sclera to 45.6±3.9 MPa after WST11/NIR treatment.

Conclusion
WST11/NIR treatment significantly increases the biomechanical strength of rabbit sclera and may become a treatment for progressive myopia.