During vitreoretinal surgery, the surgeon identifies the ora serrata. This structure marks the boundary between which two zones, and what is the clinical significance of the peripheral retina near this boundary?

• A Between neural retina and pars plana of ciliary body; site where retinal tears causing detachment commonly occur ✓
• B Between iris and ciliary body; site of aqueous humor production
• C Between posterior pole and midperipheral retina; site of choroidal detachment
• D Between vitreous base and retinal vessels; site of vitreous hemorrhage

Explanation

The ora serrata is the serrated anterior margin of the neural retina where it transitions to the non-photosensitive pars plana (ciliary epithelium) of the ciliary body. The vitreous base straddles the ora serrata, attaching firmly just anterior and posterior to it. This strong vitreoretinal adhesion at the vitreous base means that tractional forces during posterior vitreous detachment can create horseshoe tears at or just posterior to the ora serrata — the most common site for rhegmatogenous retinal detachment. The pars plana is also used as the approach for vitrectomy ports (3.5–4 mm from limbus).

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.