Presumed Foveal Bacillary Layer Detachment in a Patient With Toxoplasmosis Chorioretinitis and Pachychoroid Disease

Abstract

Purpose: To report a detachment that apparently separated photoreceptor inner segment myoids from inner segment ellipsoids as a manifestation of toxoplasmosis chorioretinitis in a patient with pachychoroid spectrum disease.Methods: Multimodal imaging including fundus photography, spectral domain and enhanced-depth imaging optical coherence tomography (OCT), indocyanine green angiography, and OCT angiography.Results: A 33-year-old man with a history of toxoplasmosis chorioretinitis reported 1 week of decreased vision to 20/200 in his right eye. Examination of the right eye demonstrated mild vitritis with recurrent chorioretinitis inferior to the fovea and adjacent to a chorioretinal scar. A dome-shaped, foveal photoreceptor layersplitting detachment was noted on OCT. Because degenerating cone photoreceptors are capable of shedding their inner segments, we inferred the location of the detachment at the level of the inner segment myoid and provided a histological example of such from an unrelated donor case. In addition, multimodal imaging revealed dilated choroidal veins (pachyvessels) with attenuation of the inner choroid in both eyes and asymptomatic findings of central serous chorioretinopathy in the left eye. After 1 month of antibiotic and steroid therapy, the chorioretinitis resolved, as did the detachment. Hyperreflective foci on the vitreoretinal interface were appreciated with en face OCT that appeared to aggregate throughout the course of therapy, induce inner retinal striae, and resolve without inducing epiretinal membrane formation.Conclusion: Patients with preexisting pachychoroid spectrum disease may manifest a more significant retinal fluid accumulation in the setting of superimposed chorioretinal inflammation. In this case of macular toxoplasmosis chorioretinitis, inflammation manifested as a retinal detachment at the level of photoreceptor inner segment myoids that we named as a bacillary layer detachment. In this case, inflammatory sequelae of toxoplasmosis reactivation responded well to oral and intravitreal therapy.

Biometrics, Impact, and Significance of Basal Linear Deposit and Subretinal Drusenoid Deposit in Age-Related Macular Degeneration

“…Eyes preserved 9 hours after death were processed as described above. Aspects of this case, including bacillary layer detachment 47 and lipid coverage of BrM, 22 have been published. In this study, we computed BLinD volume, using 22 stepped sections through the macula of the left eye (mean distance, 156 ± 17 µm; range, 90–180 µm).…”

Quantifying Retinal Pigment Epithelium Dysmorphia and Loss of Histologic Autofluorescence in Age-Related Macular Degeneration

“…The most common artifacts are detachment of outer segments from RPE that may or may not take RPE apical processes with them (e.g., figure 5 of Ref. 32), detachment of inner segments at the myoids (bacillary layer detachment),50 and detachment of RPE from Bruch's membrane at sites of basal linear deposit and soft drusen 51,52. We do not see in histology splits through the middle of RPE suggesting that only the basolateral half of cells are present in flat mounts.…”

Cone mitochondria act as microlenses to enhance light delivery and confer Stiles-Crawford-like direction sensitivity

“…1A ). This notion is supported by observations that this region is fragile and may be the source of detachment in certain retinal diseases 30 . Further, cone OS were typically detached by the removal of the RPE, likely due to the tight ensheathment of OS by RPE interdigitation between cones, and their presence vs. absence did not impart any evident systematic differences upon the optical data presented below.…”