Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
, 5 (Suppl 1), 23
eCollection

Wide-field Fundus Autofluorescence Imaging in Patients With Hereditary Retinal Degeneration: A Literature Review

Affiliations
Review

Wide-field Fundus Autofluorescence Imaging in Patients With Hereditary Retinal Degeneration: A Literature Review

Akio Oishi et al. Int J Retina Vitreous.

Abstract

Background: Inherited retinal degeneration (IRD) refers to a heterogenous group of progressive diseases that cause death of photoreceptor cells and subsequent vision loss. These diseases often affect the peripheral retina, objective evaluation of which has been difficult until recently. Fundus autofluorescence (FAF) is a non-invasive retinal imaging technique that depicts the distribution of intrinsic fluorophores in the retina. The primary source of retinal autofluorescence is lipofuscin, which is contained in the retinal pigment epithelium (RPE). Excessive accumulation of lipofuscin and a window defect attributable to loss of photoreceptor pigment result in increased FAF whereas loss of the RPE results in decreased FAF. These changes can be seen during the course of IRD.

Mainbody: While conventional modalities are limited in their angle of view, recent technologic advances, known as wide-field and ultra-widefield FAF imaging, have enabled visualization of the far peripheral retina. Although clinical application of this technique in patients with IRD is still in its infancy, some studies have already indicated its usefulness. For example, an area with decreased FAF correlates well with a visual field defect in an eye with retinitis pigmentosa (RP) or cone-rod dystrophy. An abnormal FAF pattern may help in the diagnosis of IRD and associated diseases. In addition, female carriers of X-linked RP and female choroideremia show characteristic appearance. Conversely, absence of abnormal FAF despite severe retinal degeneration helps differentiation of cancer-associated retinopathy.

Conclusion: This paper reviews the principles of FAF, wide-field imaging, and findings in specific diseases. Wide-field imaging, particularly wide-field FAF, will provide further information for the characteristics, prognosis, and pathogenesis of IRD.

Keywords: Cone-rod dystrophy; Confocal scanning laser opthalmoscope; Fundus autofluorescence; Optomap; Optos; Retinal degeneration; Retinal dystrophy; Retinitis pigmentosa; Wide angle.

Conflict of interest statement

Competing interestsAs stated above, this submission was supported by Optos. There are no other competing interests.

Figures

Fig. 1
Fig. 1
Principle of ultra-widefield imaging using the confocal scanning laser ophthalmoscope developed by Optos. An ellipse has two foci, and light passing through one focus and reflecting at the inner surface of the ellipse always passes through the other focus. Thus, light emitted from one of the foci (F1) always passes through the other focus (F2) where the center of the pupil is placed. The direction of light can be changed when a galvanometer mirror is placed at F1. Taking advantage of this property, ultra-widefield retinal imaging of even a small pupil became possible
Fig. 2
Fig. 2
Comparison of conventional measurement of the angle of view and the angle used by the Optos system. Whereas the angle of view has traditionally referred to the angle at which light enters the eye, the Optos measures the angle from the center of the eye. The 200° from the center of the eye corresponds to approximately 125° measured in the conventional manner
Fig. 3
Fig. 3
Example of image distortion in response to transformation of the sphere into a plain image. We took a retinal image using a model eye with a vertical scale inside. Note that peripheral portion is magnified, and the vertical scale is distorted. (left) The Optos algorithm compensates for this distortion. (Right) Recent models have an additional algorithm to measure the theoretically correct length and area on the image
Fig. 4
Fig. 4
An ultra-widefield fundus autofluorescence (FAF) image and Goldmann perimetry of an eye with retinitis pigmentosa. An increased ring of FAF is observed in the macula. In addition, the retina nasal to the optic disc shows slightly stronger FAF despite decreased FAF in the surrounding area. (arrows) This phenomenon is known as nasal sparing and is a characteristic finding in retinitis pigmentosa. The visual field results correspond well with the FAF findings
Fig. 5
Fig. 5
Optical coherence tomography and ultra-widefield fundus autofluorescence (FAF) in a 59-year-old patient with retinitis pigmentosa (RP; left) and an 82-year-old patient with subacute vision loss and night blindness (right). Optical coherence tomography revealed thinning of the paracentral outer nuclear layer and loss of the ellipsoid zone in these two patients. However, ultra-widefield FAF shows minimal changes in the patient on the right compared to the patient on the left. In RP, development of a granular and patchy area of decreased FAF depends on patient age and duration of the disease [43]. Thus, it is very unlikely that a patient with RP in the ninth decade of life would show almost normal FAF. The patient was screened for a systemic tumor, and lung cancer was detected. The patient was finally diagnosed with cancer-associated retinopathy
Fig. 6
Fig. 6
Ultra-widefield fundus autofluorescence (FAF) images of a patient with choroideremia (left) and his mother (right). Patients with choroideremia show patchy or granular areas of decreased FAF throughout the retina. Large choroidal vessels are sometimes visible in the decreased FAF area. Interestingly, an asymptomatic female carrier may show an abnormal reticular or mottled pattern of FAF. This finding may help in the diagnosis
Fig. 7
Fig. 7
An ultra-widefield fundus autofluorescence (FAF) image and Goldmann perimetry of a patient with cone-rod dystrophy. The macula is severely affected and shows decreased FAF. Perimetry confirmed a central scotoma corresponding to this area
Fig. 8
Fig. 8
An ultra-widefield fundus photograph and a fundus autofluorescence (FAF) image of a patient with Stargardt disease. An area of foveal atrophy shows decreased FAF. No characteristic flecks are evident on the photograph but easily recognizable areas of increased FAF were detected (arrows). A demarcation line is often observed in this disease as well as in retinitis pigmentosa and is considered to represent a closed optic fissure [71] (arrowhead)

Similar articles

See all similar articles

References

    1. Warburg M, Moller HU. Dystrophy: a revised definition. J Med Genet. 1989;26(12):769–771. doi: 10.1136/jmg.26.12.769. - DOI - PMC - PubMed
    1. Wright AF, Chakarova CF, Abd El-Aziz MM, Bhattacharya SS. Photoreceptor degeneration: genetic and mechanistic dissection of a complex trait. Nat Rev Genet. 2010;11(4):273–284. doi: 10.1038/nrg2717. - DOI - PubMed
    1. Berger W, Kloeckener-Gruissem B, Neidhardt J. The molecular basis of human retinal and vitreoretinal diseases. Prog Retin Eye Res. 2010;29(5):335–375. doi: 10.1016/j.preteyeres.2010.03.004. - DOI - PubMed
    1. da Cruz L, Dorn JD, Humayun MS, Dagnelie G, Handa J, Barale PO, Sahel JA, Stanga PE, Hafezi F, Safran AB, et al. Five-year safety and performance results from the Argus II retinal prosthesis system clinical trial. Ophthalmology. 2016;123(10):2248–2254. doi: 10.1016/j.ophtha.2016.06.049. - DOI - PMC - PubMed
    1. Russell S, Bennett J, Wellman JA, Chung DC, Yu ZF, Tillman A, Wittes J, Pappas J, Elci O, McCague S, et al. Efficacy and safety of voretigene neparvovec (AAV2-hRPE65v2) in patients with RPE65-mediated inherited retinal dystrophy: a randomised, controlled, open-label, phase 3 trial. Lancet. 2017;390(10097):849–860. doi: 10.1016/S0140-6736(17)31868-8. - DOI - PMC - PubMed

LinkOut - more resources

Feedback