5.3.2. Chooses, fits and manages the correction of presbyopic patients.

Question 1

Choosing multifocal spherical CL

Answer 1

• Up to date spec Rx
• Ocular dominance
  1. Sensory dominance test
  1. Px kept binocular; target 1 line above worst VA
  1. Place +1.00 in front of eye with rx in place
  1. Swap the +1.00 between eyes
  1. “Which feels the most uncomfortable?”
  1. Most uncomfortable = dominance eye
  1. No difference noted = reduce blur / may not have strongly dominant eye
• Initial adaptation
• Adjusting:
  +0.25 to non-dominant eye to enhance reading
  -0.25 to dominant eye to enhance distance
• Flipper lenses used not phoropter

Question 2

1. Simultaneous design (most MFs)

Answer 2

• Look through D & N rx at the same time
• Visual system learns to select the appropriate rx through the lens, depending on the object distance
• Concentric
  1. Can be centre near or centre distance
  1. Distance or near power is in the centre surrounded by concentric rings of N & D powers
• Aspheric
  1. Distance or near power is in centre, with a gradual transition to other powers as you move away from the centre (similar to varis)
  1. 1 day moist multifocal has an aspheric centre near design. The optical design varies to account for pupil size variation according to age and refractive error.

Question 3

2. Segmented/translating

Answer 3

• Like bifocal/trifocal specs
• D power is in the centre & upper zones
• N power is in the lower portion of the lens
• Bottom lens edge is flattened to keep lens from rotating
• Visible line
• Px switches between rx’s by looking up & down as in bifs
  *

Question 4

Multifocals – advantages and disadvantages

Answer 4

Advantages

• Maintain binocular vision
• Can see all distances – D, I & N
• Opteyes – toric now available, up to 5.75

Disadvantages

• Compromised vision (any presbyopic CL is) – 6/7.5, N8
• No daily toric option
• 15-day adjustment period
• Px may experience aberrations/flare if pupil size is larger than optic zone

Question 5

Monovision

Answer 5

• 1 eye is corrected for distance & the other for near
• Visual system alternates central suppression when alternating between distance & near targets
• Causes slight reduction in DVA & non-significant reduction in NVA
• Establish ocular dominance using +2.00 test
  1. Px looks 1 line above worst VA
  1. +2.00 is shown to RE then LE & px is asked which is more comfortable
  1. Dominant eye = eye not covered by +2.00
  1. If px can’t tell difference – reduce the blur (i.e., +1.00 instead)
• Dominant eye = distance correction as would normally prescribe for CLs (considering BVD / cyl)
• Non-dominant eye = near correction (distance correction would prescribe for this eye which incorporates px’s near add)

Question 6

Monovision advantages and disadvantages

Answer 6

**Advantages **

• Good for early presbyopia (problems for +2.00 upwards)
• Easy to fit (range of lens designs, materials & modalities)
• Reduced chair time
• Less costly for px’s

**Disadvantages **

• Reduced stereopsis & contrast – no binocular vision
• Glare when driving at night
• Adaptive period (developing suppression) – takes 1 week or so
• Limited intermediate vision
• Unsuitable for monocular px’s

Question 7

Final Option

Answer 7

• Distance SV CL with addition of RR’s for close work
• Good vision
• Toric correction available
• Little adaptation
• However, px still must have glasses.

Question 8

Pushing plus

Answer 8

reduces the disparity between distance and near powers ,making it easier for the brain to adapt to multifocal optics. It means less accommodation is used making things more comfortable for the patient