Ora Serrata

• The posterior neural (photosensitive) retina - the part that detects light
• The anterior non-photosensitive retina - which continues forward as the ciliary body epithelium

Location

• It sits approximately 6-7 mm anterior to the equator of the eye
• It lies between the choroid (posteriorly) and the ciliary body (anteriorly)
• Marks the anterior limit of the vitreous base

Nasal vs. Temporal Asymmetry

• The nasal ora serrata is about 1 mm closer to the limbus than the temporal side
• Nasal side has broader bays and is easier to visualize clinically
• Temporal side is more posteriorly located

Cell Junctions at the Ora Serrata

• Non-pigmented epithelial cells of the pars plana are held together by tight junctions, adherens junctions, and desmosomes
• The pigmented epithelium is more firmly attached on the pars plana side
• Retina just posterior to the ora serrata attaches to the pigmented epithelium via desmosomes (but not tight junctions)

Clinical Significance

• This is a common site for retinal tears and detachments, especially lattice degeneration
• It is the posterior boundary of the pars plana, the surgical access route used in vitreoretinal surgery (pars plana vitrectomy)
• The vitreous base straddles the ora serrata and is the most firmly attached part of the vitreous - making it resistant to detachment