Peripapillary changes on OCT scans are
being increasingly reported in glaucoma patients. This could be due to better
awareness of these changes or improvement in the instrumentation.
Peripapillary retinoschisis (PPRS) is more
than 10 times commoner in glaucoma patients, compared to healthy controls.
This condition is defined as the visible
splitting of the inner or outer neurosensory retinal layers.
The condition is often seen along an
existing RNFL bundle defect.
In a study by Sung et. al, the schisis
appeared on OCT cross-sections as splitting of the superficial prelaminar
tissue. It is usually accompanied with floating retinal vessels which are
cleaved from the underlying prelaminar structures.
PPRS is attributed to differential shear forces
exerted by lateral tension, causing deformation and remodeling of the
load-bearing tissues in the ONH. It also impacts distant tissues through the retinal
vessels, internal limiting membrane (ILM) and macroglia (Muller cells).
Lowry found PPRS was commoner in eyes with
thinner minimum rim width and a deeper cup.
This condition is regarded as a possible
risk factor for further glaucomatous damage.
PPRS can cause artifacts in OCT image
segmentation and diagnostic metrics, leading to overestimation of the rim
tissue thickness and underestimation of the cup depth.
REFERENCES:
Lowry EA, Mansberger SL, Gardiner SK, Yang H, Sanchez F, Reynaud J, Demirel S, Burgoyne CF, Fortune B. Association of Optic Nerve Head Prelaminar Schisis With Glaucoma. Am J Ophthalmol. 2021 Mar;223:246-258. doi: 10.1016/j.ajo.2020.10.021. Epub 2020 Nov 6. PMID: 33166501; PMCID: PMC7979447.
Fortune B. Pulling and Tugging on the Retina: Mechanical Impact of Glaucoma Beyond the Optic Nerve Head. Invest Ophthalmol Vis Sci. 2019 Jan 2;60(1):26-35. doi: 10.1167/iovs.18-25837. PMID: 30601928.
Sung: https://www.ajo.com/article/S0002-9394(21)00329-9/abstract
Steven L. Mansberger: https://ark.meetingfiles.com/my-ark/view-session/?sid=5ae8ad13-a6c4-4c45-9865-547a51e0c811
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