Artificial Iris Implants for Aniridia & Oculocutaneous Albinism: Does Near Infra-Red Light Transmission Risk Retinal Phototoxicity?

Abstract

 

Purpose

 

Artificial iris implants for traumatic or congenital aniridia and oculocutaneous albinism aim to restore iridocosmesis and the light occlusive properties of the absent or deficient anatomical iris. The native human iris serves an important function in protecting the posterior segment from retinal hazard light (400-1400nm). Artificial iris implants must replicate this photoprotective function across the retinal hazard range. The occlusive properties of clinically available artificial iris implants are unknown. This study aimed to evaluate light transmission through clinically used artificial iris implants.

 

Methods

 

Spectral transmission was recorded across five Morcher BDI (67B/67F/67G/67L/68/94A) and two Dr Schmidt Artificial Iris implants using broad-spectrum and NIR LED light sources and a spectroradiometer. Near-infrared (NIR) light as a percentage of total retinal incident light was calculated in actual daylight, incandescent and fluorescent light environments to simulate retinal exposure through each aniridia implant.

 

Results

 

Dr Schmidt’s Artificial Iris demonstrated occlusion of all wavelengths of light. All Morcher BDI iris implants demonstrated high levels of NIR transmission across the black iris interface, accounting for up to 82% of total retinal incident light in incandescent environments.

 

Conclusions

 

Morcher BDI iris implants transmit high-levels of near infra-red light (700-1400nm) within the retinal hazard range. This may risk long-term retinal photochemical toxicity across the life of the implant. Dr Schmidt’s Artificial Iris implants may offer improved safety and efficacy for functional iris restoration in this patient group.

 

 

Figure 1. Intraocular lenses and model eye used in the study. (a) Morcher Black Diaphragm Iris (BDI) Aniridia implant 67B (b) Morcher BDI aniridia implant 67F(c) Morcher BDI aniridia implant 67G (d) Morcher BDI aniridia implant 67L (e) Morcher BDI aniridia implant 68 (f) Morcher BDI aniridia implant 94A (Morcher GmbH, Stuttgart, Germany) (g) Artifical Iris silicone prosthesis with brown iris pigmentation (h) Artifical Iris silicone prosthesis with hazel iris pigmentation (i) Posterior black occlusive aspect of Artififical Iris implant (Dr Schmidt Intraocularlinsen GmbH). Lens images presented taken by author using a macro enabled digital camera.

 

Keywords: 571 iris • 688 retina • 670 radiation damage: light/UV