OPTM4102 Anterior Chamber PDF

OPTM4102 Anterior chamber 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...

OPTM4102 Anterior chamber 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 Anterior chamber Posterior Chamber https://menafn.com/ Anterior chamber angle Junction between cornea and iris Drainage of aqueous humour Standring S, et al. Gray’s Anatomy, 40th Edition. 2008. Elsevier Anterior chamber angle Schwalbe’s Line Anterior TM Posterior TM Scleral Spur Ciliary Body Iris Anterior chamber angle: gonioscopy Schwalbe’s Line Anterior TM Posterior TM Scleral Spur Ciliary Body Iris A: Ciliary body B: Scleral spur C: Trabecular meshwork D: Schwalbe’s line https://www.academy.org.uk/lectures/barnard12.htm https://online-ce.opt.pacificu.edu/ Histology: iris insertion Iris root inserts into anterior border of ciliary Cornea body Iris Ciliary sulcus refers to the space between Iris Root posterior surface of iris Ciliary base and anterior ciliary Body body Ciliary Sulcus = depression, Sulcus furrow http://www.lab.anhb.uwa.edu.au/mb140/Big/cil04vg.jpg Histology: scleral sulcus Shallow indentation posterior to limbus Cornea Bridged by trabecular meshwork (posteriorly) Scleral sulcus Sclera and forms Schlemm’s Scleral spur canal (anteriorly) http://www.lab.anhb.uwa.edu.au/mb140/Big/cil04vg.jpg Histology: Schwalbe’s line Termination of Descemet’s Schwalbe’s Line Anterior TM membrane Posterior TM Most anterior structure of angle Scleral Spur Ciliary Body Corneal endothelium transitions to Iris trabecular meshwork (TM) TM TM Schwalbe’s Line Corneal Endothelium Corneal Endothelium http://histology.med.umich.edu/medical/eye Histology: trabecular meshwork Connective tissue beams enclosed by trabecular cells Schwalbe’s Line Avascular ‘lamellated meshwork’ Anterior TM ~ Sieve, filter Posterior TM Schwalbe’s line to scleral spur Scleral Spur Trabecular cells phagocytose debris Ciliary Body ~ Keep sieve clean Iris https://pubmed.ncbi.nlm.nih.gov/25216121/ Histology: trabecular meshwork Three regions ~Uveal meshwork Closest to AC Collagen and elastic lamellae network Large openings between lamellae https://pubmed.ncbi.nlm.nih.gov/27183473/ https://pubmed.ncbi.nlm.nih.gov/14500801/ Histology: trabecular meshwork Three regions ~Corneoscleral meshwork Middle layer Perforated collagen and elastin plates covered by TM cells Connects SS to anterior wall of scleral sulcus https://pubmed.ncbi.nlm.nih.gov/27183473/ https://pubmed.ncbi.nlm.nih.gov/14500801/ Histology: trabecular meshwork Three regions ~Juxtacanalicular/Cribiform meshwork Loose CT Sieve-like plates Main source of resistance o aqueous flow (smallest pores) https://pubmed.ncbi.nlm.nih.gov/27183473/ https://pubmed.ncbi.nlm.nih.gov/14500801/ Trabecular cells Phenotype Location Cell Behaviour Responsibilities Endothelial Uveal/corneoscleral Endothelia Maintain passageway patency Neutralize reactive oxygen species Macrophage Biological filter/phagocytosis Immune mediation Fibroblastic Juxtacanalicular tissue Fibroblast ECM turnover/tissue repair Smooth muscle Contractile tone Mechanotrasduction https://pubmed.ncbi.nlm.nih.gov/27443500/ Histology: Schlemm’s canal Outer Wall ~Closest to sclera ~Monolayer of endothelial cells ~Well developed basement membrane ~Cells have no transcellular microchannels Inner Wall ~Closest to TM ~Monolayer of endothelial cells, with an incomplete sub-endothelial layer ~No basement membrane ~Tight junctions between cells ~Paracellular and intracellular pores to facilitate fluid transport https://pubmed.ncbi.nlm.nih.gov/27183473/ Histology: scleral spur Posterior wall of Schlemm’s canal Site of anterior ciliary muscle attachment ~ Prevents Schlemm’s canal from collapsing under ciliary muscle contraction Spur = urge forward http://www.lab.anhb.uwa.edu.au/mb140/Big/cil04vg.jpg  Venous drainage of aqueous TM → Schlemm’s canal → collector channel → ~Direct: collector channel to episcleral plexus ~ Indirect: collector channel to deep scleral plexus or intrascleral plexus then to episcleral plexus Episcleral plexus → vortex system → ophthalmic veins Snell RS, Lemp MA. Clinical Anatomy of the Eye. Blackwell Science. 1998. https://eyewiki.aao.org/Cavernous_Sinus_Syndrome  Pressure independent - Uveoscleral drainage * more important when thetrabecularmeshwork isnoucona ~10% drainage ~Fluid pass between the uveal trabeculae and ciliary muscle bundles → drain to the episclera ~Some fluid reaches the suprachoroidal space before entering the vessels draining via the vortex veins ~Affected by drugs and state of accommodation (ciliary muscle) https://pubmed.ncbi.nlm.nih.gov/21293732/  Ciliary muscle on aqueous flow Ciliary Muscle Relaxed Ciliary Muscle Contracted ↓ trabecular ↑ trabecular ↑ uveoscleral ↓ uveoscleral Summary Anterior chamber angle Trabecular meshwork components Two outflow routes of aqueous humour