Anatomy and Refractive Media of the Eye Sonie Umbara, MD Anatomy Eyeball, Orbit & Adnexa Anatomy Eyeball Dimension Anterior Chamber Posterior Chamber

Vitreous Cavity Anatomy

Conjungtiva • Transparent membrane • Richly vascular • Protective

2. Iris • Part of uvea • Contains blood vessels and connective tissue

1. Ciliary Body • Part of uvea Uveal Tract • Produce aqueous humor 3. Choroid • Attached to zonule Anatomy 3 layers

The Refractive Media The media passed by light before reaching the retina Anatomy Precorneal Tear Film

• Functions: • Produce smooth optical surface • Lubrication • Oxygen & nutrients diffusion • Protection • Layers: • Lipid layer • Aqueous layer • Mucin layer Anatomy Cornea

• Avascular, transparent • Refractive medium (40-44D) • Diameter (V:9-11 mm, H:11-12 mm) • Thickness (central:0,5mm, perifer: 1mm) Aqueous humour

■ Transparent colorless fluid. ■ It fills anterior and posterior chambers of the eye. It is formed continuously by the ciliary epithelium ■ Refractive by diffusion and active transport and drained by Nourishment of medium, its canal of Schlemm at corneo-scleral junction the avascular refractive index ■ Rate: 1-2 ul/min cornea and lens is 1.33

Keeps the eyes Maintains rigid and intraocular maintains its pressure refractory power Lens

■ It is an elastic biconvex, transparent circular lens. ■ It is about 11 mm in diameter. ■ It is suspended to the ciliary body by the suspensory ligament. ■ It has a refractive power of 20 D during rest, but its power increase during accomodation to near vision ■ 1/3 refractive power of eye ■ It has a refractive index of about 1.40 Vitreous body

■ Refractive medium, its refractive index is 1.34. ■ Supports the retina. ■ Supports the lens. ■ Maintains the spherical shape of the eye.

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