Fundus Autofluorescence Imaging in a Patient With Rapidly Developing Scotoma

Abstract

Purpose To evaluate the findings in a case of acute macular neuroretinopathy involving sudden development of scotomas accompanied by rapid focal increases in fundus autofluorescence. Methods The clinical presentation of the patient was documented by color fundus photographs, fundus autofluorescence, infrared imaging, and high-resolution spectral domain optical coherence tomography. The scotomas were assessed by Humphrey visual field 10-2 and MP-1 microperimetry. Results Visual field defects exhibited spatial correspondence with wedge-shaped lesions demonstrable in color fundus photographs and infrared imaging. It was notable that the lesions exhibited increased intensity on autofluorescence images obtained within 3 weeks of presentation. Optical coherence tomography revealed focal loss of photoreceptor inner segment/outer segment junctions in both eyes. Conclusion This case was distinguished by the relative rapidity with which the lesions became hyperautofluorescent in fundus autofluorescence images. Given that the bisretinoids that are the source of autofluorescence form in photoreceptor cells and are transferred to retinal pigment epithelium secondarily, the rapid increase in autofluorescence is unlikely to only reflect retinal pigment epithelium status and is more likely to be indicative of photoreceptor cell dysfunctioning and loss of structural integrity.

New associations of classic acute macular neuroretinopathy

“…The migraines and use of oral contraceptives (case 6), both factors previously associated with AMN, may have had additive effects contributing to the onset of AMN 4 23. The number of risk factors may determine extent and severity of ischaemia, and thus the size of AMN lesions in this series, similar to previously published cases with multiple associated risk factors that had large, rather unusual centre-involving AMN lesions 15 17…”

“…This is not characteristic for AMN, as most previous reports have described either no visible FAF changes, subtle hypoautofluorescent changes on 488 nm FAF or subtle hyperautofluorescent changes on 787 nm FAF 2 16. However one previous report detected AMN lesions presenting with subtle hyperautofluorescence on 488 nm FAF similar to our case 17. Although this finding is not characteristic for AMN, it can be explained by the reduction of filtering of blue light by decreased visual pigment density in outer segments, seen on OCT as loss/disruption of the IZ 18 19.…”

Comparison of Near-Infrared and Short-Wavelength Autofluorescence in Retinitis Pigmentosa

“…We have previously suggested that disease-related patterns of hyperautofluorescence in SW-AF images may be indicative of a lipofuscin synthetic pathway that is accelerated because the disabled photoreceptor cells are unable to meet the demand for detoxification of all-trans-retinal, the latter being generated by photoisomerization of visual pigment. 15,16 That photoreceptor cells within the borders of the hyperautofluorescent ring were impaired in the present study was indicated by decreased visual sensitivities on the MP-1, and loss of the ISe band on SD-OCT across the width of the AF ring. The source of the aberrant SW-AF across the ring could be the photoreceptor cells themselves, degenerating photoreceptor debris, or RPE cells after phagocytic transfer of the fluorophores.…”

Quantitative Fundus Autofluorescence in Mice: Correlation With HPLC Quantitation of RPE Lipofuscin and Measurement of Retina Outer Nuclear Layer Thickness

“…We previously have provided evidence that increased fundus AF can accompany photoreceptor cell dysfunctioning and degeneration. 30,45 Thus, perhaps the pronounced fundus AF after 8 months of age reflects the photoreceptor cell degeneration documented by ONL thinning. The identities of the bisretinoids accounting for this continued increase in qAF are not known, but they are unlikely to include A2E as the latter fluorophore exhibited decreased levels after 8 months of age.…”