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Victoria Fan, Ibraim Vieira, Michael Sun, Mark Rosenblatt, Charles Yu; Optical performance of electronic keratoprosthesis. Invest. Ophthalmol. Vis. Sci. 2020;61(7):3576.
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© ARVO (1962-2015); The Authors (2016-present)
The electronic keratoprosthesis or intraocular projector is a novel approach for restoring vision in patients with intractable corneal blindness. Previous studies have so far demonstrated a visual acuity limit of 20/127. The purpose of this work is to optimize and produce higher levels of optical performance.
Conceptually, the prosthesis is an intraocular implant that bypasses the damaged cornea and projects images directly onto the retina. 30 two-lens combinations were tested and modeled in ZEMAX (Zemax Development Corporation, Bellevue, Washington, USA), an optical design program. An optical system was then constructed from commercially available lenses (Edmunds Optics, Barrington, United States), placed in front of a 9.5 x 7 x 7 mm CyberDisplay WQVGA LVSTM (Kopin, Westborough, United States), and tested on a 16-megapixel complementary metal oxide semiconductor (CMOS) camera sensor (Panasonic, Kadoma, Japan).
The physically constructed retro-focusing system (21.7 mm total axial length) consisted of a double concave lens (6.0 mm Dia. x -12 mm FL) placed 2 mm from the microdisplay (10.5 μm pixel pitch) and a plano-convex lens (5.0 mm Dia. x 5.0 mm FL) placed 4 mm from the negative lens. The system projected in-focus images onto a simulated retina plane 12.3 mm away, at a magnification of 1X, producing a visual acuity equivalent of 20/40. With custom lenses modeled in ZEMAX, it was possible to reduce magnification to 0.46X or a visual acuity equivalent of 20/20. The quality of the projected images could be further optimized with an achromatic doublet or other aberration-reducing lenses.
With a multiple lens system, the electronic keratoprosthesis could restore 20/20 vision in patients blinded by corneal opacity, thus providing a new treatment option for patients who may not be ideal candidates for cornea transplantation or traditional keratoprostheses.
This is a 2020 ARVO Annual Meeting abstract.
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