5.3.2 Chooses, fits and manages correction of presbyopic pxs

Question 1

What is presbyopia?

Answer 1

Impaired near vision due to diminished accommodation caused primarily by loss of elasticity of cystalline lens.
Sx: 40-45yo.

Question 2

What are the options for presbyopia and CLs?

Answer 2

• Distance lenses & reading add glasses: little adjustment required, but px still has to wear specs on top
• Bifocal CLs: px looks through distance portion of CL in primary gaze. On down gaze, lens is held up by lower lid and px accesses near portion
  Monovision
  Multifocals

Question 3

Describe monovision contact lenses?

Answer 3

• Works on principle that visual system can suppress eye that is not needed for visual task
• Dominant: distance Rx, non-dominant: near Rx

+ves: wide range of CLs to choose from to suit px’s everyday & health related needs.
Good distance vision in poor lighting

-ves: decreased binocularity & depth perception. Poor speed of focussing. Poor IV especially in +2.00 add

Good candidates: early presbyopes - lower add means px is more likely to tolerate it
Pxs with multiple pairs of gls. Pxs who have not got on with varifocals.

Bad candidates: monocular or high levels of unequal VA. As brain needs to process distance & near information from both eyes & fuse it together.
Overly high expectations/hypercritical: VAs unlikely to be as good as glasses.
Pxs with specific visual tasks: require good VAs for fine detail or depth perception

Question 4

Describe SS Umere/Clariti 1day MF?

Answer 4

SS Umere/CV Clariti 1 day:
- consists of 4 concentric circles
- reading (central most circle)
- reading - intermediate, -intermediate-distance
- distance (most peripheral circle)
Centre near MF design, Dk/t 86.
WetLoc Technology: creates naturally wettable CL resists dehydration. Locks in moisture & distributes water molecules through CL, mimicking moisture dispersion of naturally healthy eye.

Question 5

Describe SS Linarial/CV MyDay MF?

Answer 5

• Consists of concentric rings.
• Binocular Progressive System: designed to help achieve clear VA at all distance:
  Low add: aspheric centre near design
  Medium add: aspheric centre near design
  High add: spherical centre near design w/ dual intermediate zones
  Dk/t: 100

Question 6

Describe SS Opteyes/CV Biofinity MF?

Answer 6

• Comes in 2 designs: centre distance and centre near
• Fit: both eyes: give ‘centre D’, works best in low add pxs
  OR ‘centre D’ in dom eye, ‘centre N’ in non-dom eye, best for pxs with higher adds
  e.g. RE dominant: -1.25/-0.25 x 170, LE -2.25, Add +2.50
  Prescribe RE -1.25/+2.50 D, LE -2.25/+2.50 N

Biofinity Toric MF also available

Question 7

Describe Alcon DT1 MFs?

Answer 7

• Up to date Rx. Add +0.25D to most plus spherical equivalent Rx for each eye. Determine lowest acceptable add for functional vision then use table:
  Up to +1.25D Low BEs, +1.50 to +2.00D medium BEs, +2.25 to +2.50D high BEs
• Design: additional minus in lens to minimise aberrations
• Smooth progression of power gradients. Centre near

Question 8

Describe multifocal CLs - +ves, -ves and good and bad candidates?

Answer 8

+ves: maintains binocularity
-ves: period of adaptaiton
Good candidates: early presbyopes - lower add means px is more likely to tolerate it
Monovision wearers. Pxs w/ multiple pairs of glasses.

Bad candidates: monoular pxs/high levels of unequal VA: brain needs to be able to process distance & near info from both eyes and fuse it together
Overly high expectations/hypercritical: VAs unlikely to be as good as in glasses
Astigmats with cyls >0.75DC as rx given is BVS, hard to tell if struggling with MFs or w/o cyl if poor vision

Question 9

What should you get px to do after fitting MF CLs for first time?

Answer 9

• for 20mins px goes for walk and has look
• subjectively score D &N out of 10
• if rx needs to be changed, use binoc flippers ONLY
  -dom eye: if change helps in distance, make sure it’s not negatively impacting vision at near
• non-dom eye: if change helps at near, make sure it’s not negatively impacting distance vision
• if poor CL fit and power profile is not in pupil centre, px will not access appropriate Rx correction and VA will be poor

Question 10

Multifocal RGP Lenses - how do they work?

Answer 10

• Work by steepening RGP to create +ve tear lens at near, allowing px to see up close and at distance
• all available in 7-9mm in 0.05mm steps
• Contraindications:
  High riding lens: doesn’t create +ve tear lens
  >2.00DC or keratoconus: unstable platform: variable vision/unreliable reading add due to compromised fit

Question 11

How do you determine ocular dominance?

Answer 11

• Motor (hand triangle) - dom eye is one where target mostly lined up w/ triange. Can be affected by head posture/position.
• Use fix disparity - bar which slips is less dominant eye.

Sensory: more accurate -assesses which image is selected as predominant by visual cortex
+1.00 blur on distance Rx in one eye. Get px to rate out of 10. Repeat for other eye. The least comfortable/lower score out of 10 eye is dominant.

Question 12

What are tips for fitting presbyopic CLs?

Answer 12

Never use a phoropter - always flipper lenses or trial lenses
Never adjust add power - only adjust distance to help