OPTM4102 Choroid Record (PDF)

OPTM4102 Choroid Dr. Jason Charng [email protected] Acknowledgement of country The University of Western Australia acknowledges that its campus is situated on Noongar land, and that Noongar people remain the spiritual and cultural custodians of their la...

OPTM4102 Choroid Dr. Jason Charng [email protected] Acknowledgement of country The University of Western Australia acknowledges that its campus is situated on Noongar land, and that Noongar people remain the spiritual and cultural custodians of their land, and continue to practise their values, languages, beliefs and knowledge. Artist: Dr Richard Barry Walley OAM Objectives Choroid anatomy ↓ & Retina btw Sclera -  thins with age 7. Choroid => main function : supply outer - retina ↳. avascular , photoreceptors H of the outer retina have high receive blood arteries supply from the posterior Ciliary. metabolic activity Underneath the retina, highly vascularised Supplied by SPCA and LPCA, drains via vortex veins ~200 µm thick at birth, decrease to 80 µm by 90 yo https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2913695/  Choroid Functions ~Supply nutrients and O2 to outer retina # TR ~Thermoregulation (via heat dissipation) due > - to the high blood flow Within the choroid Innerocular pressure ~IOP modulation via blood flow control e ~Aqueous humour drainage via uveoscleral pathway - Appro 10-15% of drainage in humans Choroid Arterial vessels interspersed with veins 5 layers makeupchoriadnecan't be distinctly ~Note that Haller’s separated aka Haller’s layer and Sattler’s layers ↑ are histologically defined and do NOT aka Sattler’s layer have precise borders in imaging https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2913695/  Bruch’s membrane => ECM Avascular undergo changes with age. , ~ 2-4 µm thick Elastin and collagen-rich ECM Function Regulate movement of : molecules between RPE and choroidal circulation Aging changes ~Fibre calcification ~Increased fibre cross-linkage ~Accumulation of fat and advanced https://pubmed.ncbi.nlm.nih.gov/19747980/ glycation end products Choriocapillaris => thin sheet of capillaris to Bruch membrane next thickest at forea ~ 10 µm thick at fovea, thinning to ~7 µm peripherally Feeder arteriole from Sattler’s layer supplies hexagonal area https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2913695/ Sattler’s & Haller’s layer Sattler’s layer ~ 100 µm thick Contains medium to small sized vessels choriocapillaris Sattler's layer Haller’s layer ~ 200 µm thick Haller's layer Contains large sized vessels https://pubmed.ncbi.nlm.nih.gov/26502006/ Suprachoroid ~ 30 µm thick Transition between · choroid and sclera Contains collagen fibres, fibroblasts and melanocytes Of pharmacological interest as drug delivery targeting chorioretinal layer https://pubmed.ncbi.nlm.nih.gov/30953867/  Clinical assessment of the choroid – indocyanine green (ICG) angiography Sodium fluorescene is use to investigate blood flow in aka choroidal refini. 90 see after dye 10 mins after angiography injection , retinal dye injection. Vessels are visible retinal Vessels Appear as generalized not as bright hyperfluorescence i. Dye has exit the retina observe into Injecting ILG dye , choroid the filling of the dye. ICG angiography after dye ↳techniques e mints => 30 choroidal vessels , injection. & as dark ones O. the integrity Octa appears vessels visible. choroid No retinal to choroidal : Dye is leaving circulation. https://entokey.com/indocyanine-green-angiography/ Clinical assessment of the choroid – OCTa Relatively new Non-invasive, detects movement of RBCs Produces enface imaging ofOG retina and choroid vessels https://www.nature.com/articles/s41598-018-34102-6 Normal OCTa - outer retina Normal OCTa - choroid CNV OCTa - outer retina CNV OCTa - choroid https://pubmed.ncbi.nlm.nih.gov/31321222/ Vogt–Koyanagi–Harada’s disease ICGA – choroidal granuloma OCTa areas small dark , these In blood vessels- is no there dye present No green https://pubmed.ncbi.nlm.nih.gov/35982638/ Age-related macular degeneration (AMD) - Bruch's membrane becomes thicker - Drusen form due to accumulation of waste material in Bruch's membrane ② https://www.webrn-maculardegeneration.com/bruchs-membrane.html Summary Choroid critical in retinal homeostasis Choroid consists of 5 layers Introduced imaging techniques assessing choroid in the clinic