Glaucoma Flashcards
GDD indications
- Severe conj scarring
- Uncontrolled glaucoma e Trab
- 2 glaucoma ….
GDD complication
- Malposition (endo/lens)
- Tube erosion, plate migration
- Excessive drainage
- Early drainage failure (blockage of tube)
- Late drainage failure (10%/yr)
- Diplopia
NTG RF
- Elderly, female, Japan, Fh/o
- CCT lower
- Abnl vasoregulation- migraine, raynaud, DM, HT, carotid insufficiency
- Hypotension
- OSA
- Autoantibodieslevel
- Transient pressure gradient
- Ocular perfusion pressure lower
- Myopia
- Thyroid d/s
Tx outline of NTG
Regular assessment- perimetry 4-6 monthly
Reduce IOP 30% from baseline slow rate of progression
but without Tx 50% of NTG -> no progression at 5 yr
RF of progression
- Female
- Migraine
- Disc haemorrhage at Dx
Tx of NTG
- Medical
- Brimonidine (neuroprotective)
- CAI dorzolamide(ocular perfusion)
- Pg
- Betaxolol (ON perfusion)
- SLT
- Surgery
- Control of systemic vascular d/s
- CCB for vasospasm
- Reduce antiHT at night
- Neuroprotective (memantine, ginkgo, antipl
D/Dx of NTG
- Angle closure
- Low CCT
- POAG
- Previous episode of raised IOP
- Masking by systemic Tx (Oral B blocker)
- Spontaneously resolved pigmentary G
- Progressive RNFL defects not d/t G
- myopic degeneration
- OD drusen
- Cong disc anomalies- OD pit, coloboma
- ON or chiasmal compression
- Previous AION
- Previous acute ON insult
- Other ON - inflammatory, infiltrative, drug
OD changes more common in NTG
- Greater rim thinning
- PPA crescent more common
- Splinter haemorrhage more common
- OD pallor more than cupping
- OD pits more common
VF changes more common in NTG
- VF loss closer to fixation
2. Steeper slopes
Devices used to measure IOP
- GAT
- Pneumotonometry
- Perkins
- Pascal (DCT)
- Reichert (ORA)
- Tonopen
- iCare
- Schiotz
- Implantable tonometer
Goniolens
1. Indirect
A) Non-indentation
1) Goldmann 3 mirror
2) Magna view
3) Ritch trabeculoplasty
4) Khaw direct view
B) Indentation
1) Zeiss
2) Posner
3) Sussman
- Direct
1) Koppe
2) Barkan
3) Swan Jacob
Trabeculum PIGMENT
- PXF, PDS
- Iritis
- Glaucoma (post ACG)
- Melanosis
- Endocrine (DM, Addison)
- Naevus (cogan Reese$)
- Trauma
Blood in Schlemm canal
- CCF
- SW $
- SVC obstruction
- Ocular hypotony
- Post gonioscopy
Shaffer system
G 0 - iridocorneal touch
G 1 - Schwalbe seen, closure high
risk, not inevitable
G 2 - trabeculum seen, closure possible
G 3 - S spur seen, incapable of closure
G 4 - CB seenAnatomical limbus
Anterior limit formed by a line joining end of Bowman and end of Descemet (Schwalbe line)
Posterior limit is a curve line marking transition between regularly arranged corneal collagen fibers to haphazardly arranged sclera collagen fiber
Pathological limbus
Anterior limit - same
Posterior limit formed by line perpendicular to surface of conjunctival epithelium about 1.5 mm behind end of Bowman membrane
Surgical limbus
Annular band 2 mm wide with posterior limit overlying scleral spur
Divided into
- anterior blue zone (bet BM and Schwalbe)
- posterior white zone (bet Schwalbe and SS)
GDD contraindications
Borderline endothelial function
Contact lens use - erosion
Sites of GDD implant
STQ - first
INQ - larger plate
SNQ - smaller plate (SO m/m)
Soil-> inferior Q is preferred
Sites of plate and tube
EO plate is sutured bet V and H recurs m/s, posterior to m/s insertion
Tube is routed in 1 of 3 ways
- Anteriorly to enter AC angle parallel to iris
- Into ciliary sulcus in pseudophakic with posterior facing bevel entering 2.5mm from limbus
- Through PP, 4mm to limbus, for posterior implantation in eyes a/f complete vitrectomy
Tube is covered with sclera, pericardium or cornea
Failed blew
- Flat without vascularization
- Vascularized bleb due to episcleral fibrosis.
- Encapsulated bleb (Tenon cyst) characterized by
a localized
highly elevated,
dome-shaped,
fluid-filled cavity of hypertrophied Tenon capsule, often with engorged surface blood vessels.
Causes of failure can be classified according to the site of obstruction:
- Extrascleral causes include subconjunctival and episcleral
- Scleral causes include over-tight suturing of the scleral flap and gradual scarring in the scleral bed.
- Intraocular causes are uncommon and include blockage of the sclerostomy by vitreous, blood or uveal tissue or by a variety of thin membranes derived from surrounding cornea or sclera.
Posterior embryotoxon
Prominent and anterior displaced Schwalbe line
S/- thin, grey-white arcuate ridge on the inner surface of the cornea adjacent to limbus
Ass - Axenfeld-Reiger anomaly
- Alagille $
Axenfeld-Reiger $
Caused by defective NCC related processes during fetal development
PAX 6 gene mutations
AD
Axenfeld anomaly
Posterior embryotoxon + anterior peripheral iris strands
Reiger anomaly
Posterior embryotoxon +
iris stromal hypoplasia+
Ectropion uveae+
correctopia and full thickness iris defect
Reiger $
Reiger anomaly +
Dental anomalies (hypo, micro)+
Facial anomalies (maxillary hypo, broad Nadal bridge, telecanthus, hypertelorism)
Others (redundant paraumbilical skin and hypospadias, hearing loss, hydrocephalus, cardiac and renal anomalies, congenital hip dislocation)
