unit 6 Flashcards
1
Q
Prior to contact lens fitting
A
- Visual acuity
o glasses vs cl - Refraction
- Corneal curvature
o steep vs flat - Corneal diameter
o Horizontal visible iris diameter (HVID) is 1.5mm smaller than corneal diameter
o Slit lamp or topographer
2
Q
Slit lamp exam- what to check
A
- Lids and lashes
o Blepharitis/MGD -> Dryness, discomfort, deposits - Lid margins
o No entropion/ectropion (lids turning inwards/lids turning outwards) - Eyelid position
o Scleral show (more visible scleral than normal)
o Small aperture
o Tight eyelids - Tear film
- Bulbar conjunctiva
o Pterygia/pinguecula (growth on the conjunctiva) - Palpebral conjunctiva
o Papillae - Cornea
o Neovascularization (not enough oxygen getting to the cornea)
o Scars
o Staining
3
Q
Prescription Consideration
A
- Sphere power
o >4.00 - Astigmatism power
o >0.75 - Astigmatism axis
- Add power (presbyopia)
4
Q
Should high minus in glasses be higher or lower in CL
A
should be lower in CL
5
Q
So if the vertex distance is 12mm what should the presciprtion be for a -8.00 and +7.00
A
-8.00 in glasses are going to turn into -7.25
+7.00 in glasses will turn into +7.50
So when it is a minus lens it should increase by 0.25 and if it is a plus lens it should increease by 0.50
6
Q
Is there a -3.00 astigmatism CL available?
A
No, the closet is -2.75
7
Q
Other Considerations for CL
A
- Expectations/motivation
- Hobbies/lifestyle
- Work
- Medical history/medication