Gonioscopy (M1) Flashcards
What is the purpose of gonio?
assess the anterior chamber angle
What are the four different gonio brand lenses?
- Zeiss
- Posner
- Sussman
Which mirror in the 3 mirror gonio lens is used for the anterior angle?
D-shaped mirror
What are the types of coupling solutions that can be used for 3 mirror gonio?
- goniosol
- celluvisc
- preservative free artificial tears
What is the degrees of incline for each of the mirrors in the 4 mirror gonio lens?
59-62 deg
What are the benefits of 4 mirror over 3 mirror?
- coupling solution not required and easier to apply
- requires minimal rotation for 360 deg views
- easier to compare between two eyes
- small lens better for small apertures
- allows for indentation gonio
What occurs if there is too much or asymmetric pressure applied with 4 mirror?
corneal wrinkling and folds
What does increasing the pressure on the central cornea during indentation gonio cause?
artificially open a narrow angle
What does too much pressure on the central cornea during indentation gonio cause?
blood to back up from Schlamm’s canal, leading to a pale pink appearing line in posterior TM
What are the benefits of 3 mirror over 4 mirror?
- higher quality views
2. no corneal folds
What is the disinfectant cleaning procedure done for the practical for the gonio lenses?
- clean with Boston GP cleaner
- rinse with saline
- soak in Opticide for 3 minutes
- allow to dry
- rinse with saline
What is the order of the structures seen in the anterior angle?
- iris
- ciliary body
- scleral spur
- pigmented TM
- non-pigmented TM
- Schwalbe’s line
What is always documented following gonio?
- most posterior structure found
- iris insertion
- pigmentation (0-4)
- peripheral anterior synechiae (+/-)
When is a convex or steep iris insertion seen?
- hyperopia
2. narrow angles
When is a flat iris insertion seen?
normal patients
When is a concave iris insertion seen?
- myopia
2. Pigment dispersion syndrome
What is the grade (and description) of the angle when the ciliary body band is the most posterior structure seen in gonio?
4 (wide open)
What is the grade (and description) of the angle when the ciliary body band somewhat visible or scleral spur is the most posterior structure seen in gonio?
3 (open)
What is the grade (and description) of the angle when the scleral spur/TM is the most posterior structure seen in gonio?
2 (narrow)
What is the grade (and description) of the angle when the anterior portion of TM is the most posterior structure seen in gonio?
1 (extremely narrow)
What is the grade (and description) of the angle when there are no structures seen in gonio?
0 (closed)
What is the procedure for the corneal wedge technique?
- w/ gonio on eye, narrow beam to optic section
- create 45deg angle with beam
- scroll up with slit lamp until splits into two (at Schwalbe’s line)
What are the potential side effects of gonioscopy?
- vasovagal syncope
2. transient SPK
What is the transient loss of consciousness with rapid onset, short duration with spontaneous, prompt and complete recovery? 1. What are the other transient loss of consciousness’ that need to be ruled out? 2
- vasovagal syncope
2. seizure, hypoglycemia, cardiac arrest