Choroid

Special Thanx to Nishna Bharathan(2007-2011)optometry batch Alsalama College Of Optometry,Perinthalmanna)

1. CHOROID OPTOM.ASKAR.PK

2. CHOROID Post part of vascular coat Extends from optic disc to ora serrata Inner surface is smooth, brown& lies contact with RPE Outer surface is rough &contact with sclera

3. MICROSCOPIC STRUCTURE 3 LAYERS Supra choroidal lamina Stroma of the choroid Basal lamina

4. Supra choroidal lamina : Thin memb of condensed collagen fibres , melanocytes &fibroblast Continuous ant with supraciliary lamina The potential space B/W this memb & sclera is called suprachoroidal space Which contain long & short post ciliary arteries & nerve

5. Stroma of the choroid : Loose collagenous tissue with elastic & reticular fibres Contain pigments & plasma cells Main bulk is formed by vessels -3 layers -layer of large vessels (haller`s layer) -layer of medium vessels (sattler`s layer) -layer of choriocapillaries –nourishes the outer layers of the retina

6. Basal lamina Also called Bruch's memb& lines the layer of choriocapillaries Lies with RPE 5 layers-basement memb of rpe Inner collagen layer Middle elastic layer Outer collagen layer Basement memb of choriocapillaries

7. BLOOD SUPPLY TO THE UVEAL TRACT 3 ARTERIAL SUPPLY: Short post ciliary arteries Long post ciliary arteries Ant ciliary arteries

8. Short post ciliary arteries Arise as 2 trunk from ophthalmic arteries Divide 10-20 branch which pierce in sclera around optic nerve & supply choroid

9. Long post ciliary artery: 2 –nasal &temporal Pierce sclera obliquely on medial &lateral side of optic nerve & run forward in supra choroidal space to reach ciliary muscle

10. Ant ciliary arteries Derived from ophthalmic artery 7 in no: 2 from SR,IR,MR &1 from LR These pass ant to episclera , give branch to sclera,limbus& conju Pierce sclera near limbus to enter ciliary muscle Anastomose with 2 LPCA form- circulus arteriosus major- near root of iris

11. Venous drainage: Ant ciliary veins Smaller veins from sclera The venae verticosae (post ciliary veins)

12. 1)-are tributaries of muscular vein Since Carry blood only from ciliary muscle-small arteries 2)-Carry blood only from sclera & not from choroid- smaller than arteries Correspond to short ciliary arteries

13. 3) 4 in no: S & I temporal S &I nasal Pierce sclera obliquely on each side of SR& IR muscles Drain blood from whole of choroid Small vein from optic nerve head, retina also Tributaries from iris , ciliary process, ciliary muscle, ant choroid 4 veins converge at apex of orbit 2 sup vortex vein open to S ophthalmic vein& I VV to I ophthalmic vein

14. PHYSIOLOGICAL CONSIDERATIONS 1- It is the source of blood flow to the ocular tissues 2 - Site of aq humor production &maintain IOP 3 - Constitute blood aq barrier 4 -Musculature of the ciliary body play role in process of accommodation 5 - Eicosanoids are synthesized in iris & ciliary body 6 - Play role in detoxification & antioxidation in ant segment

15. Eicosanoids in iris & ciliary body Is generic term to describe prostaglandins & leukoterienes Both are metabolites of arachidonic acid Prostaglandins synthesized in great amt after trauma or inflammation of iris , ciliary body from arachidonic acid released by esterified site in phospholipid memb )

16. Many other peptides are present in iris, CB & aq including neuropeptide , y calcitonine gene related peptide- CGRP Cyclo -oxy pathway in microsomes many of the peptide modulate Normal function –PGE2- miosis & PGF2alpha- control iop by AQ production CGRP RELAXES;Iris dialator Also have immunosuppressive role

17. Detoxification &anti oxidation in the ant seg The cytochrome p 450 system is the major drug detoxification in the eye - microsomes contain a group of protein –cp450- catalyze transfer of a single o2 atom to exogenous or endogenous substance for detoxification Convert hydrohpobic to hydrophillic compounds Highly reactive comp by conju to glutathione Most enzyme invoved detoxification process –in CB

18. The ciliary body is the main source of antioxident system in the ant seg Exist in cornea, lens CB is rich in antioxidant with high conc of catalase ,superoxide dismutase& glutothionine peroxidates type i & type ii Type I selanine dependent – reduction of oxydised glutathionine,by detoxification of peroxides Type ii selanine independent

19. THANK YOU