Gonio 1 Flashcards
3 methods of gonioscopy
Indirect: Scleral and corneal
Direct: Koeppe
Critical angle
46.5 degree
About direct goniolens
Primarily used in surgery Pt must be supine Portable system with +50D power Observer must move to view angles 120 degree view Steeper curvature compared to K Image direct and upright Not likely to extend pressure on cornea or limbus
3 mirror
What do these angles view
60/66/76
60- Far periphery/angles
66- periphery
76- mid periphery
Scleral lens advantages and disadvantages
Advantages:
Suction
Undistorted view and good optics
Better view thru disrupted K
Disadvantages: Coupling solution Difficult insertion Requires rotation Cannot do compression/indentation gonio
Corneal gonio advantages and disadvantages
Advantages: Easy insertion Quick No rotation Can do compression/indentation gonio Anesthetic only
Disadvantages: Poor quality Transient image Poor stabilization Pressure on lens can cause widening of angle and folds
Normal anterior chamber angle depth
3.4mm
How does angle depth vary based on refractive error and gender and location
Myopes > hyperopes
Men > women
Inferior angle widest > nasal = temporal > superior angle narrowest
How does the CB band enhance aqueous outflow
Contracting the longitudinal, oblique and circular fibers
This lowers IOP
How does CB band width vary with race
Caucasians angle wider than african americans/asians.
Asians have smaller eyes and are at most risk for angle closure.
primary site of aqueous outflow
Trabecular meshwork
What area of TB has the most pigmentation
Inferior quadrant
More posterior- near SS
Conventional and non-conventional pathway of aqueous outflow thru TB
Conventional (85%): Superior TB –> JCT –> Schlemm’s –> scleral and episcleral plexus
Nonconventional (15%): Travels through posterior uveal meshwork
What kind of flow does schlemm’s canal have?
Segmental flow. Does not occur throughout all 360 degrees. Only in certain sections of the TM.
TB abnormalities
Pigment dispersion: Glaucoma
Pseudoexfoliation
Trauma
Uveitis
