Detection of singlet oxygen luminescence for experimental corneal rose bengal photodynamic antimicrobial therapy.

Jeffrey C Peterson,Irene Kochevar,Fabrice Manns,Keenan J Mintz,Esdras Arrieta,Jean-Marie Parel,Roger M Leblanc,Ernesto H Weisson,Juan D Silgado,Marco Ruggeri

doi:10.1364/boe.405601

Abstract

Rose bengal photodynamic antimicrobial therapy (RB-PDAT) treats corneal infection by activating rose bengal (RB) with green light to produce singlet oxygen (1O2). Singlet oxygen dosimetry can help optimize treatment parameters. We present a 1O2 dosimeter for detection of 1O2 generated during experimental RB-PDAT. The system uses a 520 nm laser and an InGaAs photoreceiver with bandpass filters to detect 1O2 luminescence during irradiation. The system was validated in RB solutions and ex vivo in human donor eyes. The results demonstrate the feasibility of 1O2 dosimetry in an experimental model of RB-PDAT in the cornea.

Highlights

Corneal infection is a common ocular emergency which can lead to permanent damage to the cornea and possible blindness and complete loss of the eye due to endophthalmitis [1]
Preliminary studies demonstrate the potential of Rose Bengal Photodynamic Antimicrobial Therapy (RB-PDAT) as a therapy for treating microbial keratitis [4,5,6,7,8]
While D2O increases 1O2 signal in solution compared to H2O by lengthening 1O2 lifetime, rapid reaction of 1O2 with nearby amino acid dramatically reduces 1O2 lifetime, negating the signal boosting effects of D2O observed in solution

Summary

Introduction

Corneal infection (keratitis) is a common ocular emergency which can lead to permanent damage to the cornea and possible blindness and complete loss of the eye due to endophthalmitis [1]. Preliminary studies demonstrate the potential of Rose Bengal Photodynamic Antimicrobial Therapy (RB-PDAT) as a therapy for treating microbial keratitis [4,5,6,7,8]. While preliminary results have been promising (>80% of patients treated with experimental RB-PDAT avoid emergency cornea transplant), a better understanding of the fundamental photochemical processes for generating 1O2 is required to maximize treatment efficacy [8]. The goals of the optimization include maximizing 1O2 production, maximizing treatment depth, and minimizing treatment time [11,12]. To make this possible, an accurate measure of 1O2 dose must be established

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