Optical-Quality Assessment of a Miniaturized Intraocular Telescope

Abstract

Age-related macular degeneration (AMD) causes severe vision impairments, including blindness. An option to improve vision in AMD patients is through intraocular lenses and optics. Among others, implantable miniaturized telescopes, which direct light to healthy lateral regions of the retina, can be highly effective in improving vision in AMD patients. Yet, the quality of the restored vision might be sensitive to the optical transmission and aberrations of the telescope. To shed light on these points, we studied the in vitro optical performance of an implantable miniaturized telescope, namely, the SING IMT™ (Samsara Vision Ltd., Far Hills, NJ, USA) designed to improve vision in patients affected by late-stage AMD. Specifically, we measured the optical transmission in the spectral range 350-750 nm of the implantable telescope with a fiber-optic spectrometer. Wavefront aberrations were studied by measuring the wavefront of a laser beam after passing through the telescope and expanding the measured wavefront into a Zernike polynomial basis. Wavefront concavity indicated that the SING IMT™ behaves as a diverging lens with a focal length of -111 mm. The device exhibited even optical transmission in the whole visible spectrum and effective curvature suitable for retinal images magnification with negligible geometrical aberrations. Optical spectrometry and in vitro wavefront analysis provide evidence supporting the feasibility of miniaturized telescopes as high-quality optical elements and a favorable option for AMD visual impairment treatments.

Keywords: SING IMT™; end-stage age-related macular degeneration; geometrical aberrations; implantable ophthalmic device; intraocular lens; optical performance; visual impairment; visual prosthesis.

Figure 3

Transmission properties in the UV-Vis. Experimental normalized transmission spectrum of the SY60WF monofocal IOL (A) and SING IMT™ device (B). The vertical blue, green, and red lines mark the wavelength values of 450, 550, 650 nm.

Figure 1

Optical transmission spectroscopy. (A) Schematic description of the optical fiber setup used for measuring the transmission spectra of the intraocular optics. (B) Reference spectrum of an ideal transmitter measured in air without any intraocular optical elements in the optical path.

Figure 2

Wavefront sensing setup. (A) The beam exiting a laser module is filtered and expanded with two lenses and a pinhole. (B) A shear plate is used to set the distance between the lenses, thus ensuring collimation. (C) A fraction of the laser beam is imaged and processed with a beam profiling algorithm in order to determine the beam waist. (D) The reaming fraction of the beam is directed towards the intraocular lens under test and the resulting wavefront measured and expanded in Zernike polynomials.

Figure 4

Wavefront sensing and geometrical aberrations characterization. (A) Reconstructed wavefront and (B) Zernike coefficients of SING IMT™ device. (C) Reconstructed wavefront and (D) Zernike coefficients of SY60WF monofocal IOL. For clarity of comparison, the Zernike coefficients of each lens are normalized with the absolute value of the defocus term. The optical path difference (OPD) is defined as the difference between the aberrated and the ideal wavefronts. Pupil diameter: 3.3 mm.