Treatments for corneal blindness are limited by a high rate of complications and may not be as effective in cases of severe ocular surface damage. With this in mind, researchers have invented an intraocular implant that projects light directly onto the retina, bypassing the damaged cornea, as an alternative approach for treating corneal opacity. The device captures light via an external camera and then wirelessly sends data to an intraocular microdisplay.
The team will present their findings tomorrow at the 2019 ARVO conference in Vancouver. They found that the intraocular projector can restore vision in people blinded by corneal opacity, possibly providing a more accessible solution to those who may not be ideal candidates for corneal transplants or keratoprostheses.
The researchers successfully constructed four functioning implants (9.5mm x 7mm x 7mm; approximately 360mg). With a lens (focal length of 3mm) placed 4mm from the microdisplay, they found that the devices produced a visual acuity of up to 20/127. They measured the resulting image quality and visual acuity with a calibrated eye chart, and assessed the biocompatibility of the external projector components as well as other measures of viability for use in human subjects.
They note that the external materials were non-toxic and that three of four devices remained functional after three months in accelerated wear conditions. One goal of the team is careful temperature control when placing an electronic device in a living eye. External temperature testing demonstrated a 1.78°C increase after one hour and a 75mW device implanted in a living rabbit eye for 30 minutes exhibited a peak temperature increase of 1°C.
|Fan V, Rosenblatt M, Sun M, et al. Intraocular microdisplay projection system for treating corneal blindness. ARVO 2019. Abstract 4697-B0260.|