SIGN Glaucoma

Question 1

Components of a glaucoma referral

Answer 1

• history
• iop
• CCT
• AC assessment
• VF
• disc assessment
• imaging

Question 2

When to refer based on IOP results

Answer 2

• > 25mmHg irrespective of of CCT
• 21-25 and CCT <555nm and aged under 65

Question 3

When to refer based on anterior chamber assessment

Answer 3

• refer if gonio shows 270 degrees or more of the angle the trabecular mesh work if not visible
• VH angle with less than 1/4 thickness of the cornea

Question 4

What to look for when checking anterior chamber

Answer 4

• Pseudoexfoliation
• pigment dispersion
• iridotomy

Question 5

Considerations when referringbased on visual fields

Answer 5

• minimum of 2 visual field tests with consistent findings
• is there a defect
• does it match disc appearance
• use same equipment
• has the mean defect changed by more than 2db

Question 6

When should px be referred based on disc assessment

Answer 6

• px with one or more of the following findings should be referred to
  
  • optic disc haemorrhage
  • disc asymmetry (difference of 0.2 CD)

Question 7

When to refer summary

Answer 7

Irrespective of intraocular pressure, patients with one or more of the following findings should be referred to secondary eye care services”
• Optic disc signs consistent with glaucoma in either eye
• A reproducible visual field defect consistent with glaucoma • Risk of angle closure
• Using Van Herricks technique, a peripheral angle with of less than a quarter of the corneal thickness
• Using Gonioscopy, when posterior trabecular meshwork is not visible for ≥ 270 degrees”
• “IOP is >26mmHg - irrespective of CCT”
• “IOP 21-26, central corneal thickness is <555μmand patient is aged under

Question 8

Limitations of DDLS

Answer 8

• poorer at monitoring diffuse NRR loss
• doesn’t work well with unusual discs
• monitors thinnest areas, but if focal loss occurs elsewhere then grade may not change

Question 9

Benefit of slit lamp for disc assessment

Answer 9

• better field of view
• better illumination
• stereoscopic view
• easier to navigate the fundus
• image size less effected by refractive error

Question 10

Steps of a disc assessment

Answer 10

• assess disc size
• narrowest rim to disc
• scrutinise where the neuro retinal rim ends around the whole disc
• judge cup on bend of vessels
• look for glaucomatous disc features

Question 11

Advantages of DDLS

Answer 11

• good repeatability
• strong correlation with glaucomatous visual fields
• better specificity than cup to disc

Question 12

Corrective factor for 90D lens

Answer 12

X 1.30
- 1.1- 1.5 M is medium disc on 90D lens