MT 3

Glycogen

• formation of glycogen in cornea vs no allowed in limbus

  • FIH-1: inhibiting enzyme

  • used when no O2

Closed eye

• palp. conj + AH = source of O2

• low O2 shifts to anaerobic glycolysis (increase lactate) + low pO2 due to high elevation

• high lactate = swelling

• Low pH = reduction in pump function

• Edema - hypotonic tears and hypoxic metabolism

Lactate transport

• lactate higher in stroma vs AH

• lactate moves to AH via monocarboxylate cotransporters

• Lactate cannot cross into tear film

Contact lenses

• lowers O2 leading to anaerobic metabolism

• 74mmHg = minimum level of O2 exposure

• Dk/t

  • diffusivity, solubility of O2, thickness

• contact lenses act as a barrier to CO2 shifting bicarbonate equilibrium

CO2

• Lactate is acid of eye

• increase with anaerobic metabolism

Low pH

• Acidosis

  • pump function decreased

  • reduce deturgescence

Diseases of Hypoxia

• epithelial microcysts

• epithelial thinning

• Stromal striae

• Endothelial blebs

• Endothelial polymegethism

Neovascularization

• imbalance of anti / pro angiogenic factor

• Treatment: ranibizumab/ bevacizumab, VEGF antibodies, Corticosteroids/ NSAIDs

AH

AH drainage

• through TM, into schlemm’s canal, collector channels, deep scleral/ intrascleral/ episcleral plexus, and episcleral vein

• Across iris root, uveal meshwork, anterior face of ciliary muscle, through connective tissue, into suprachoroidal space

BAB

• Non leaky tight junction of:

  • Non pigmented epithelium of ciliary body

  • Posterior Iris

  • Iris vasculature

  • Inner wall of schlemm’s canal

• Non fenestrated blood vessels of the iris

AH Protein