Impact of cigarette smoking on fluorescence lifetime of ocular fundus

Abstract

Cigarette smoking is known to adversely affect cellular metabolism and is a risk factor for various retinal diseases. Fluorescence lifetime imaging ophthalmoscopy (FLIO) has the potential to detect metabolic changes in the ocular fundus. Aim of this study was to analyze the influence of cigarette smoking on fluorescence lifetime (FLT) of healthy eyes using FLIO. Twenty-six non-smokers and 28 smokers aged between 20 and 37 years without systemic and ocular diseases were investigated by FLIO (excitation: 473 nm, emission: short spectral channel (SSC) 498–560 nm, long spectral channel (LSC) 560–720 nm). The FLT at the ETDRS grid regions were analyzed and compared. In SSC, the mean FLT (τm) of smokers was significantly longer in the ETDRS inner ring region, whereas the τm in LSC was significantly shorter in the outer ring. For the long component (τ2), smokers with pack year < 7.11 showed significantly shorter τ2 in SSC than non-smokers and the smokers with pack year ≥ 7.11. There were no significant differences in retinal thickness. The lack of obvious structural differences implies that the observed FLT changes are likely related to smoking-induced metabolic changes. These results suggest that FLIO may be useful in assessing retinal conditions related to lifestyle and systemic metabolic status.

Artificial Intelligence in Fluorescence Lifetime Imaging Ophthalmoscopy (FLIO) Data Analysis—Toward Retinal Metabolic Diagnostics

“…However, it could still be questioned whether such a small dataset is nevertheless sufficient, due to its size and since no validation with a second independent dataset has taken place. In order to validate the results, we would like to add that the results of the AI evaluation agreed with the statistical results obtained by us without the help of AI, where we also found significant differences between the two groups, most notably in the inner ring of the SSC and in the outer ring of the LSC [9]. Additionally, the risk of bias was reduced by having age-matched groups and by averaging over 20 iterations of a five-fold cross validation.…”

“…Most recently, we reported a significant difference in the FLT between non-smokers and smokers in young healthy adults [9]. This result provides another strong implication that FLIO may be able to detect the metabolic state of the retina quite sensitively.…”

“…The clinical dataset used for the current approach was obtained during our previous study [9], which we referred to for further insights into the clinical dataset. This previous study was a monocentric, prospective, cross-sectional clinical study at the Department of Ophthalmology of the University Medical Center Schleswig-Holstein, Campus Lübeck, where a total number of 54 participants, 26 non-smokers and 28 smokers, were enrolled between April 2021 and September 2021.…”

“…This resulted in the 28 smokers being evenly grouped into 14 light and 14 heavy smokers. The detailed description of the FLIO method is described in our previous work [9]. Briefly, the FLIO original data consist of time-resolved photon counts at each pixel of fundus autofluorescence in the macula (30 , 256 × 256 pixels) (FLIO: Heidelberg Engineering, Heidelberg, Germany).…”

Fluorescence Lifetime Imaging Ophthalmoscopy of Mouse Models of Age-related Macular Degeneration

“…Recently, we have reported differences in FLT between young adult smokers and nonsmokers. 14 Because smoking is known to impair mitochondria function and to be one of the risk factors of ocular diseases, including AMD, this result strongly indicates that FLIO might be able to capture early indicators of certain diseases.…”