This text was reviewed by Shawn Kavoussi, MD
Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a speedy noninvasive autofluorescence imaging modality that gives further illness particulars past standard imaging modalities.
Utilizing FLIO lifetimes—that’s, the charges of autofluorescence decay—totally different autofluorescence patterns might be appreciated in affected eyes with varied retinal illnesses.
This novel know-how casts a brand new mild on fundus imaging by offering totally different colourful views of retinal illnesses that weren’t out there beforehand, and all in about 2 minutes.
“This novel know-how detects the in vivo autofluorescence lifetimes in the back of the attention,” in line with Lydia Sauer, MD, from the Division of Ophthalmology and Visible Sciences on the Moran Eye Middle, College of Utah College of Drugs, Salt Lake Metropolis, Utah.
Wholesome eyes, she defined, exhibit the identical attribute sample of brief FLIO lifetimes within the foveal heart and lengthy lifetimes on the optic nerve.
In distinction, eyes with retinal illnesses are characterised by quite a few totally different autofluorescence patterns relying on the illnesses current.
Sauer and colleagues studied the phenotypes, genotypes, and longitudinal modifications in Stargardt illness in 45 genetically characterised sufferers (imply age, 39 years), of whom 35 had the ABCA4-associated STGD1, 3 had ELOVL4-associated STGD3, and seven had PRPH2/RDS-associated macular dystrophy, the final 2 of that are just like Stargardt illness. Ten sufferers have been adopted longitudinally for a imply of 19 months.
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Three phenotypes have been recognized beforehand in sufferers with Stargardt illness ABCA4-associated STGD1.
Sort 1 is characterised by solely a central lesion, sort 2 flecks throughout the macula, and sort 3 giant atrophic areas. Imaging know-how took a step ahead with the arrival of FLIO, which additionally exhibits these lesions.
Nonetheless, FLIO additionally demonstrates each considerably totally different lifetimes among the many 3 phenotypes and that the lifetimes within the foveal heart are correlated considerably with the best-corrected visible acuity, Sauer famous.
Sauer and colleagues reported a very vital discovering,1 that’s, FLIO demonstrated that the geographic atrophy secondary to AMD has a markedly totally different look from the retinal atrophy related to Stargardt illness; in distinction, the two illnesses can seem very comparable when utilizing autofluorescence depth imaging.
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The investigators additionally reported beforehand that eyes with AMD have been characterised by a hoop with extended lifetimes which might be seen as a shift to blue on the fundus; in distinction, that sample isn’t seen in eyes with Stargardt illness.
This sample distinction facilitates simple differentiation of the two illnesses.
Sauer is also finding out the totally different genotypes in sufferers with ABCA4-related Stargardt illness.
“We consider that FLIO imaging can present variations among the many many various genetic subtypes,” she stated.
One other space of analysis curiosity is analysis of the small print in eyes with ELOVL4-associated STGD3 and PRPH2/RDS-associated macular dystrophy, that are Stargardt-like dystrophies.
“It is extremely fascinating that each one eyes with PRPH2/RDS-associated macular dystrophy confirmed flecks of brief FLIO lifetimes,” she famous.
That is noteworthy as a result of the baseline FLIO picture confirmed some flecks of brief FLIO lifetimes that weren’t seen on the baseline autofluorescence depth picture however solely appeared 1 yr in a while a follow-up picture.
“At the moment, the FLIO lifetimes are extended from brief to lengthy and the affected person we examined reported a brand new central scotoma the place an space of markedly extended FLIO lifetimes was seen on the follow-up picture,” she stated.
Sauer defined that the relevance of this analysis is that the brief FLIO flecks seem earlier than modifications seen on different imaging modalities together with OCT.
The researchers consider that when the brief FLIO lifetimes are seen, they might be reversible as a result of they precede structural retinal modifications. Nonetheless, by the point the modifications seem on different imaging modalities, reversing them could also be unimaginable.
These flecks additionally seem in some sufferers with Stargardt illness and Sauer famous that they behave the identical as in PRPH2/RDS-associated macular dystrophy.
FLIO lifetimes present a attribute sample in Stargardt illness, and totally different phenotypes might be recognized. Totally different genotypes have attribute FLIO findings.
“A very powerful discovering is that brief flecks initially recognized by FLIO imaging delay over time and these modifications seen on FLIO imaging are seen earlier than showing on OCT photos and different imaging modalities,” Sauer concluded.
Lydia Sauer, MD
Sauer is a medical guide to Tesseract Well being and receives nonfinancial help from Heidelberg Engineering.
1. Sauer L, Gensure RH, Andersen KM, et al. Patterns of fundus autofluorescence lifetimes in eyes of people with nonexudative age-related macular degeneration. Make investments Ophthalmol Vis Sci. 2018;59(4):AMD65-AMD77. doi:10.1167/iovs.17-23764