The retina exhibits an inherent autofluorescence that is imaged ophthalmoscopically as fundus autofluorescence. In clinical settings, fundus autofluorescence examination aids in the diagnosis and follow-up of many retinal disorders. Fundus autofluorescence originates from the complex mixture of bisretinoid fluorophores that are amassed by retinal pigment epithelial (RPE) cells as lipofuscin. Unlike the lipofuscin found in other cell-types, this material does not form as a result of oxidative stress. Rather, the formation is attributable to non-enzymatic reactions of vitamin A aldehyde in photoreceptor cells; transfer to RPE occurs upon phagocytosis of photoreceptor outer segments. These fluorescent pigments accumulate even in healthy photoreceptor cells and are generated as a consequence of the light capturing function of the cells. Nevertheless, the formation of this material is accelerated in some retinal disorders including recessive Stargardt disease and ELOVL-4-related retinal degeneration. As such, these bisretinoid side-products are implicated in the disease processes that threaten vision. In this article, we review our current understanding of the composition of RPE lipofuscin, the structural characteristics of the various bisretinoids, their related spectroscopic features and the biosynthetic pathways by which they form. We will revisit factors known to influence the extent of the accumulation and therapeutic strategies being used to limit bisretinoid formation. Given their origin from vitamin A aldehyde, an isomer of the visual pigment chromophore, it is not surprising that the bisretinoids of retina are light sensitive molecules. Accordingly, we will discuss recent findings that implicate the photodegradation of bisretinoid in the etiology of age-related macular degeneration.
piretinal membranes are commonly encountered in retinal practice, and they result in decreased vision. The present work addresses whether peeling of the internal limiting membrane is necessary during vitrectomy for macular pucker. We performed a retrospective analysis to investigate the effects of "single peeling," in which only the epiretinal membrane was peeled, and "double peeling," in which the internal limiting membrane was also stained and peeled. Although significantly more patients in the single-peeling group had an epiretinal membrane remaining in the central fovea postoperatively, visual acuity was not found to differ between the 2 groups in the short term. Patients who had an epiretinal membrane for more than 18 months had significantly worse visual acuity outcomes. Unexpectedly, there was a greater proportional decrease in central macular thickness in the single-peeling group than in the double peeling group, a finding that deserves further study.
We report the diagnosis and treatment of patients with retinal detachment and/or retinoschisis associated with optic nerve coloboma or morning glory syndrome.
Purpose
To describe the spectral domain-optical coherence tomography (SD-OCT) findings of two patients with complete defects in the retinal pigment epithelium (RPE) with disruptions in Bruch membrane in Stargardt disease (STGD1).
Methods
Two patients with STGD1 were referred to our clinic for further evaluation. Fundus autofluorescence (FAF), spectral domain optical coherence tomography (SD-OCT), electroretinography (ERG) and Microperimetry (MP-1) were performed to assess the retinal anatomy and function. Screening for mutations in the ABCA4 gene was carried out and detected mutations were confirmed by direct sequencing.
Results
Both patients had bilateral macular geographic atrophy (GA) and yellowish subretinal pisciform flecks and mutations were detected in the ABCA4 gene by chip screening. SD-OCT revealed marked atrophy of the retina in the central macula, with focal defects in the RPE with disruptions in Bruch membrane and herniation of the retina through the defect in three of four eyes.
Conclusion
This case report highlights the necessity for a detailed ophthalmic examination including SD-OCT of patients with STGD1.
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