Uveal tract anatomy and physiology with descriptions

Uveal tract is the medium part of the eye and consist of iris ciliary body and also choroid. in this presentation I will discuss about each other

1. Anatomy of Uvea Teacher : Dr. Ah. Walid Farahmand Prepared by : Ehsan Hashemi

2. Uveal Tract Main vascular layer Consists 3 parts : Iris Ciliary body Choroid In 3 sites attached to the Sclera Sclera spur exit points of vertix veins Optic nerve account for the characteristic of Ant. Chor. Detachment

3. Iris The most ant. ext of the Uvea Made up of blood vessels and connective tissue, Melanocytes and pigment cells responsible for its distinctive color Mobility/allows the pupil to change size During mydriasis: pulled into ridges and folds during miosis: its ant. Surface is smoother

4. Major structures of Iris: Stroma Vessels/Nerves Dilator M. / APE Sphincter M. Post. Pigment Epithelium

5. Stroma Compose of pigmented cells, nonpigmented cells, collagen fibers and matrix containing hyaluronic acid In blue irides stroma is lightly pigment and brown irides have a densely pigmented stroma that absorbs light

6. Vessels/Nerves Vessels form the bulk of iris stroma arising from major arterial circle and passing to the center of the iris Myelinated and unmyelinated nerve fibers serve sensory, vasomotor and muscular functions throughout the stroma

7. Dilator M. and APE Dilator M. develops from the APE

8. Sphincter Muscles Derived from neuroectoderm Composed of circular band of smooth Muscle fibers Located near the pupillary margin in the deep stroma , ant to PPE

9. Post. Pigment Epithelium Also called IPE Densely pigmented and appears velvety smooth and uniform Basal surface borders the PC and apical surface face to the ant. Iris Epithelium Curves around the pupillary margin In rubeosis iridis, PE extends farther onto the ant. Surface of the iris

10. Ciliary Body Triangular in cross section Bridges the ant. And post. Segments The apex is toward ora serrata and base is toward the iris/the only attachment of the ciliary body to the Sclera is at its base , via its longitudinal Muscle fibers, where they insert into the Scleral spur Has 2 principle functions Aqueus humor formation Lens accommodation

11. Ciliary Epithelium and Stroma 6_ 7mm wide Consist of 2 parts : Pars plana Pars plicata

12. Pars plana is relatively avascular,smooth pigmented zone 4mm wide Extends from the ora serrata to the CP The safest post. Surgical approach to the vitreous cavity is through the pars plana , located 3-4mm from the corneal limbus Pars plicata is richly vascularized consist of 70 radial folds or CP Zonular fibers attach primarily in valleys of CP and also along the pars plana

13. The ciliary body consist of double layer of Epithelial cells Non pigmented Epithelium (inner) Pigmented Epithelium ( outer)

14. Ciliary Muscles 3 layer of fibers : Longitudinal the outer layer Attach to SS 2. Radial mid portion Circular Innermost They function as unit

15. Innervation of CM Mainly parasympathetic fibers of CN3 97%of CM and 3% of iris sphincter Sympathetic fibers relux the CM Cholinergic drugs contract the CM and increase aqueous flow by opening up of the spaces of trabecular meshwok

16. Choroid Post. Portion of UT Nourish outer portion of retina Consist 3 layer of vessels: Choriocapillaris ( inner) Small vessels ( middle) Large vessels ( outer)

17. Bruch’s Membrane Fusion of basal lamina of RPE _ choriocapillaris Extend from opt. Disc to ora serrata Has 5 elements: BL of RPE Inner collagenous zone Elastic layer Outer collagenous zone BL of choriocapillaris

18. Choriocapillaris Continous layer of large capillaries Lying in a single plane beneath the RPE Contain multiple fenestrations

19. Thank you