Anterior and posterior chambers

• What is the anatomical term for the area located behind the iris?

  Posterior chamber
• What structures bound the posterior chamber?

  Posterior iris surface, lens, vitreous, ciliary body
• What do the ciliary processes secrete into the posterior chamber?

  Aqueous humor
• What is the function of the zonula fibers in the posterior chamber?

  They connect the ciliary body to the lens capsule
• What are the two regions of the posterior chamber?

  1. Canal of Hannover and retro zonular space
  2. Canal of Petit

  
• What is the volume of the anterior chamber?

  220 µl
• What is the primary function of Schlemm’s canal and trabecular meshwork?

  To provide an exit for aqueous humor

  
• What is the normal depth range of the anterior chamber?

  2.6 to 4.4 mm
• What forms the anterior chamber angle (ACA)?

  Between posterior cornea and anterior iris

  
• What structures bound the anterior chamber angle (ACA)?

  • Schwalbe’s line
  • Trabecular meshwork
  • Scleral spur
  • Anterior surface of ciliary body
• What is the clinical significance of the anterior chamber angle grading?

  It indicates the risk of closure

  
• What are the grades of anterior chamber angle (ACA) and their implications?

  • Grade 4: 35˚ - 45˚, incapable of closure
  • Grade 3: 25˚ - 35˚, incapable of closure
  • Grade 2: 20˚, closure possible but unlikely
  • Grade 1: 10˚, high risk of closure
  • Grade S: <10˚, imminent closure
  • Grade O: 0˚, no corneal wedge

  
• What is Schwalbe’s line?

  An anterior border marking transition zones
• What is the shape of the trabecular meshwork?

  Roughly triangular

  
• What are the three portions of the trabecular meshwork?

  • Uveal meshwork
  • Corneoscleral meshwork
  • Juxtacanalicular tissue

  
• What is the function of the uveal meshwork?

  Adjacent to aqueous humor, facilitates drainage

  
• What is the diameter range of openings in the uveal meshwork?

  25 to 75 µm
• What characterizes the corneoscleral meshwork?

  Contains elliptic openings and trabecular sheets

  
• What is the diameter of perforations in the corneoscleral meshwork?

  5 to 50 µm
• How does the juxtacanalicular tissue differ from other parts of the trabecular meshwork?

  It has a pore tissue and cribriform layer
• What are the three layers of the juxtacanalicular tissue?

  • Inner trabecular endothelial
  • Central connective tissue
  • Endothelium of Schlemm's canal

  
• What is the average diameter of Schlemm’s canal?

  190 to 370 µm
• What is the function of the endothelium of Schlemm’s canal?

  Acts as a physiological barrier
• What is the composition of aqueous humor?

  • 99.9% water
  • Proteins (5-16 mg/100 ml)
  • Glucose (75% of plasma concentration)
  • Electrolytes (Na+, HCO−3, Cl−)
  • High ascorbic acid concentration
• What are the functions of aqueous humor?

  Provides nutrients, removes waste, maintains IOP
• What percentage of aqueous humor drains through the trabecular meshwork?

  90%

  
• What does IOP depend on?

  Rate of aqueous production and outflow resistance
• According to Ohm’s law, how is IOP calculated?

  IOP = Pv + Fs * R
• What happens to Schlemm’s canal during elevated IOP?

  • Collapse of Schlemm’s canal
  • Distention of trabecular meshwork
  • Increased resistance to aqueous outflow

  
• What is the role of high ascorbate levels in the eye?

  Protects against ultraviolet induced oxidative products
• How does the eye respond to inflammation and infection?

  Facilitates cellular and humoral responses
• Where is aqueous humor secreted in the eye?

  In the posterior chamber by the ciliary body

  
• What is the primary route of aqueous humor drainage?

  Conventional route through trabecular meshwork

  
• What percentage of aqueous humor drains through the conventional route?

  90% (70-95%)

  
• What percentage of aqueous humor drains through the secondary route?

  10% (5-30%)
• What factors does intraocular pressure (IOP) depend on?

  Rate of aqueous production and outflow resistance
• What happens to Schlemm’s canal when IOP elevates?

  It collapses, increasing resistance to outflow

  
• What occurs when Schlemm’s canal expands?

  Resistance to outflow decreases
• What is the uveoscleral pathway's characteristic during ciliary muscle contraction?

  It decreases and is pressure independent
• What effect does pilocarpine have on aqueous outflow?

  Reduces outflow