Histological Assessment of Foveal Mechanical Instability and Potential Implications for Macular Diseases.

PURPOSE

To assess areas of mechanical instability in the fovea based on a review of artifactual separations of histological sections.

METHODS

A collection of annotated high-resolution retinal histological sections of aged donors was assessed for tissue disruptions in the fovea. Sections belong to Project MACULA (https://projectmacula.org).

RESULTS

Sections (mean length, 7467 ± 491 µm) through 75 foveas were analyzed (61% [46/75] from females; mean age at death, 81.3 years). Of these, 68% (51/75) were normal-aged, and 32% (24/75) showed early non-neovascular AMD. Separation of the neurosensory retina from the RPE occurred in 96% of sections (72/75). A break between the photoreceptor inner and outer segments was observed in 57% of cases (41/72), and bacillary layer detachment was observed in 15% (11/72), primarily involving the subfoveal region. Henle fiber layer disruptions were observed in 64% of sections (48/75), being around the Müller cell cone (MCC) in 90% of cases (43/48) and extending to cone photoreceptor cell bodies in 58% (28/48). Cystic changes at the MCC occurred in 50% of sections (38/75), with partial or complete disinsertion of the MCC in 47% of these (18/38).

CONCLUSIONS

Histological sections from normal-aged and early AMD eyes exhibit frequent tissue disruptions from post mortem handling, corresponding with regions of separation observed on OCT scans of various vitreoretinal diseases. Findings suggest that foveal areas of low mechanical stability may manifest as common ex vivo artifactual disruptions. Observing how foveal tissue breaks down post mortem may provide greater insight into the pathophysiology of different vitreoretinal diseases.