Ora serrata has a scalloped appearance and is serrated much more nasally than temporally. The retina is strongly adherent to the retinal pigment epithelium at the ora serrate, the reason retinal detachment rarely extends anterior to the ora serrata. The ora serrata represents the anterior limit of the neural retina. 6 The peripheral retina is the thinnest (110–140 µm in thickness) and the retina becomes thicker as it progresses towards the posterior pole. The distance from the optic disk to the ora serrata is 23–24 mm on the temporal aspect and approximately 18.5 mm on the nasal aspect. The peripheral retina is the remainder of the retina. 3 Broadly the retinal surface can be divided into the following areas: Area centralis (commonly known as the posterior pole or central retina) 2 The average thickness of retina is 200 micrometers, it is slightly thicker near optic nerve head and near the macula and gradually thins out at the ora serrata and fovea. Human retina measures 32 mm from ora to ora along the horizontal meridian and t he total surface area of the retina in each eye is approximately 1,100 square mm. It is continuous with the optic nerve posteriorly, the site of exit of ganglion cell axons from the eye. The retina is bound externally by Bruch's membrane and on its internal aspect by the vitreous. Ora serrata has a smooth appearance temporally but serrated nasally. The ora serrata is located 4-6 mm behind ciliary epithelium and corresponds to the insertion of medial and lateral rectus muscles. The neural retina is firmly attached at its anterior termination, the ora serrata, and at the margins of the optic nerve head. The adhesion between neural retina and RPE is relatively weak. 1īetween the neural retina and RPE, there is a potential space known as subretinal space. Sensory retina extends from the optic disc to ora serrata, where it is continuous with non-pigmented ciliary epithelium. The RPE is continuous anteriorly with the pigment epithelium of the ciliary body. Sensory retina develops from the inner layer of the neuroectoderm, whereas RPE is derived from the outer layer of the neuroectoderm.
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