Engineering a Light-Attenuating Artificial Iris

Abstract

PurposeDiscomfort from light exposure leads to photophobia, glare, and poor vision in patients with congenital or trauma-induced iris damage. Commercial artificial iris lenses are static in nature to provide aesthetics without restoring the natural iris's dynamic response to light. A new photo-responsive artificial iris was therefore developed using a photochromic material with self-adaptive light transmission properties and encased in a transparent biocompatible polymer matrix.MethodsThe implantable artificial iris was designed and engineered using Photopia, a class of photo-responsive materials (termed naphthopyrans) embedded in polyethylene. Photopia was reshaped into annular disks that were spin-coated with polydimethylsiloxane (PDMS) to form our artificial iris lens of controlled thickness.ResultsActivated by UV and blue light in approximately 5 seconds with complete reversal in less than 1 minute, the artificial iris demonstrates graded attenuation of up to 40% of visible and 60% of UV light. There optical characteristics are suitable to reversibly regulate the incident light intensity. In vitro cell culture experiments showed up to 60% cell death within 10 days of exposure to Photopia, but no significant cell death observed when cultured with the artificial iris with protective encapsulation. Nuclear magnetic resonance spectroscopy confirmed these results as there was no apparent leakage of potentially toxic photochromic material from the ophthalmic device.ConclusionsOur artificial iris lens mimics the functionality of the natural iris by attenuating light intensity entering the eye with its rapid reversible change in opacity and thus potentially providing an improved treatment option for patients with iris damage.

Biologically inspired artificial eyes and photonics

“…In addition to liquid irises, wearable or implantable artificial irises have been demonstrated, which can self-adaptively control the amount of light through the irises by sensing or reacting to the ambient light intensity. These self-adaptive artificial irises could be helpful to patients of aniridia, albinism, iris coloboma, and trauma-induced iris defect [65][66][67].…”

“…Artificial irises with selfregulating light transmission were developed by using photoreactive materials [66,67]. Na et al demonstrated an artificial iris that had spoke patterns mimicking the iris frill of a human eye and could control the light transmission by spiropyran dyes embedded in a transparent polymer (figure 18(c)).…”

Tunable Artificial Iris Controlled by Photo/Thermal Exposure Based on Liquid Crystalline Elastomers

“…According to the external light intensity, the iris can regulate the size of the pupil to protect the fundus. From previous studies, [1][2][3][4][5][6] self-regulating irises based on stimuli-responsive polymers were fabricated and can be adjusted by external stimuli. Among them, liquid crystalline elastomers (LCEs) can contract or elongate along the aligning direction of the mesogens when the molecular arrangement is disturbed by external stimuli.…”