4.1.6 Prescribes and dispenses spectacles for vocational use.

Question 1

Task Analysis for occupational lenses:

Answer 1

• Tell them to describe their workstation & immediate environment
• Screen: How far away is it from you? How many screens? How big is the screen? How is the contrast & lighting? Is there glare?
• Correction: Do they already wear one?
• Posture: How is it? Are you straining?
• Environment: Are there documents around you that you’re reading?
• SVI better for just screen use

Question 2

Maths behind a reading add:

Answer 2

• Screen 55cm, reading 35cm etc.
• 1/F
• E.g. reading add = 2.25D then 1/2.25 = 44cm. Degressive of 0.75D means 1.50D if subtracted from 2.25D. 1/1.5 = 67cm. Therefore this is the range & is perfect for a screen & near task user
• 2.50D = 40cm
• 2.25D = 44cm
• 2.00D = 50cm
• 1.75D = 57cm
• 1.50D = 67cm
• 1.25D = 80cm

Question 3

Further Analysis:

Answer 3

• Task size
• Working Distance
• Size of occupational Add
• If task is still or moving
• Position of patient and task - occupation may involve moving around working environment
• Lighting accurate perception needs optimum lighting e.g. when reading, using a VDU and performing sports
• Contrast black writing on white background gives best contrast
• Colour accuracy vital in certain occupations e.g. electrician
• Stereopsis ability to judge depth crucial for some tasks e.g. threading a needle
• Possibility of hazards in workplace e.g. chemicals, mechanical and radiation

Question 4

Measurements

Answer 4

• Heights (3-5mm below pupil centre) & MONO PDs (even for occupational lenses)
• Say that you used a ruler

Question 5

Advice given:

Answer 5

• Not for driving in!
• Use at correct WD
• May require more scanning/head movement
• Return if any problems

Question 6

Lens options:

Degressive

Answer 6

• Wide field + large WD but no distance therefore no driving in them
  
  • Sola Access HD (Specsavers)
    
    • This enhanced reading lens is available in degressions of -0.75D and -1.25D
      The full reading correction should be ordered and the fitting points placed 3mm to 5mm below the pupil centres with the eyes in the primary position
      The monocular near centration distances should be specified
      Frame depth should be around 30mm

Question 8

Double D/round/executive Segs

Answer 8

• Double D/round/executive Segs
• for pilots, mechanics & electricians as they need to look up at controls of the cockpit in addition to down and need a wide enough field to manoeuvre and do so i.e. minimum of 40mm depth of lens. Segs 14mm apart, IP/RP ratio of generally 60%, bottom seg on lower limbus
  
  • Mechanic needs to see tools & near objects but also work on vehicles on a lift above them
  • The information you get during the flight is highly dependable on the screens in your cockpit. That is why we recommend staying away from a polarization feature because it could mess with the colors on the screens. Or in addition to that, it could appear that your screen is off although it is on you can´t see them with your polarization on.
  • Get an anti-reflective coating. You have a lot of little lights in your cockpit that could be mirrored from the back surface of the progressive lenses into your eye.

Question 9

E D TRIFS

Answer 9

good for security guards , TV producers etc. who need to view many VDUs