unit 6

Question 1

Prior to contact lens fitting

Answer 1

• 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

Question 2

Slit lamp exam- what to check

Answer 2

• 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

Question 3

Prescription Consideration

Answer 3

• Sphere power
  o >4.00
• Astigmatism power
  o >0.75
• Astigmatism axis
• Add power (presbyopia)

Question 4

Should high minus in glasses be higher or lower in CL

Answer 4

should be lower in CL

Question 5

So if the vertex distance is 12mm what should the presciprtion be for a -8.00 and +7.00

Answer 5

-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

Question 6

Is there a -3.00 astigmatism CL available?

Answer 6

No, the closet is -2.75

Question 7

Other Considerations for CL

Answer 7

• Expectations/motivation
• Hobbies/lifestyle
• Work
• Medical history/medication