Purchase this article with an account.
Alexandra Goz, Jurriaan Brekelmans, Arie Marcovich, Alexander Brandis, XiaoMeng Sui, Daniel Wagner, Sidney Cohen, Avigdor Scherz; Stiffening of rabbit sclera by bacteriochlorophyll derivative WST11 and near infrared illumination (NIR)through the cornea. Invest. Ophthalmol. Vis. Sci. 2018;59(9):715.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Sclera stiffening in rabbits induced by external impregnation of WST11 and NIR illumination through the cornea; Atomic force microscopy (AFM) and biomechanical study
Seventeen pairs of rabbit eyes were enucleated post mortem. One eye of each pair was randomly chosen for treatment. The pupil was dilated with tropicamide 1% drops and the episcleral tissue was removed. The sclera was impregnated with 2.5 mg/ml of WST 11 in saline for 20 minutes.Afterwards the sclera was illuminated through the cornea at 755nm (NIR) using a 3 mirror Goldman lens for 10 minutes. The incident light was measured to be 10 mW/cm2.After the treatment, the eye was dissected and the retina and choroid were removed. Thirteen pairs were assigned for biomechanical stretching and 4 pairs for AFM measurements (using JPK Nanowizard 3). Circumferential scleral strips 4 mm wide were cut from the treatment area. A similar control strip was prepared from the contralateral eye at the same position. Sclera thickness was measured by mechanical micrometer caliper. Stress-strain measurements were performed by a biomechanical tester (Minimat, Germany). Strips for AFM were washed with 2% Triton X-100 followed by several rinses with PBS and were cut in two halves, for measuring the internal and external side of the sclera. Young's modulus, was determined at the sub-micron scale by AFM indentation curves using pyramidal silicon probes, and analyzed using a Hertzian model
Biomechanical measurements demonstrated an increase of 86.37 % in the maximal stress, from 7.12 Megapascal (MPa) to 13.27 MPa (p≤0.01) after treatment. Furthermore, Young’s modulus increased by 64.38 %, from 33.72 Megapascal to 55.43 MPa (p≤0.001) after treatment. AFM measurements showed that the average Young's modulus after treatment of the internal and external sides of the sclera were 1.7 (p≤0.1726) and 3.82(p≤ 0.007) times greater respectively than untreated controls.
This novel treatment with WST11 and NIR illumination trhough the pupila induced scleral stiffening in ex-vivo eyes. This minimally invasive treatment may be suitable to halt the progression of degenerative myopia.In-vivo studies are needed to demonstrate the safety and long-term efficacy in inhibiting axial length elongation
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
This PDF is available to Subscribers Only