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Computer Vision Syndrome
Presbyopia and Dry Eye

Prescribing Lenses (2)

Occupational Progressive Lenses
Occupational Progressive Lenses Specially designed occupational PALs can often very successfully meet the patients computer vision needs as has been shown in clinical trials. These lenses are designed with progressive power technology and favor intermediate and near power in the lens design at the expense of distance power � many of the designs have no distance power in the lens.

These lenses work very well for the presbyopic patient who spends dedicated time at the computer. An advantage of these lenses is that, because of their design, the patient does not need to take them on and off when they are in the office. The powers in the center and top of the lens are usually adequate for walking around the office, attending meetings, etc. These lenses can also work for the pre-presbyope who requires an add for near work � the decreased power in the top of the lens enables them to wear them comfortably for most office tasks.

In most cases, these lenses are designed to enable the practitioner to write their usual distance/near prescription and specify the lens. The resulting lens will have the prescribed near power in the bottom of the lens and intermediate power(s) in the top of the lens according to the lens design.

Occupational progressive lenses can be successful under several conditions:

  • For early presbyopes who don�t require an add for the computer distance � the top of the lens contains a power close to the distance power � depending upon lens selected �
  • For pre-presbyopic patients who require an add for near �
  • When different adds are required for intermediate and near distances
  • The patient wears PALs for their general visual needs

Each manufacturer�s design is somewhat different � here are characteristics of some of the more commonly available occupational lenses:

Access by SOLA

  • Designed to provide near power in the bottom, intermediate power in the top
  • Two power ranges - 0.75 D power decrease 1.25D power decrease from bottom to top
  • Access power shift occurs over a 10mm section in the middle of the lens

Fitting instructions

  • write usual distance/near Rx, near Rx is placed in bottom, top is less plus according to lens design
  • fit to near pupillary distance � half frame height for regular full field frames
  • fit 5mm below top rim for half eye frames
  • 0.75 D change recommended for adds < 1.75D
  • 1.25 D change recommended for adds > 1.75D

Technica by AO

  • Designed to provide large near at bottom, intermediate in center, small distance at very top
  • Corridor length is 30mm from 15mm above to 15mm below fitting height

Fitting instructions

  • fit as a progressive, the fitting cross over pupil center
  • prescribe the distance Rx and addition power

Interview by Essilor

  • Designed for near in the lens bottom, intermediate in the top
  • There is only one power shift or decrease of 1.00 D (actual 0.86D decrease)
  • power shift or decrease occurs over a 25mm section in the middle of the lens from 10 mm above to 15 mm below fitting height Fitting instructions
  • fit like a spherical single vision lens for near, with the fitting cross at the lower pupil margin
  • write usual distance/near Rx, near Rx is placed in bottom, top is less plus according to lens design

Office by Shamir

  • Designed for near in the lens bottom, intermediate in the top
  • Three designs with different dynamic powers 0.75D (actual 0.84D decrease),1.25D (actual 1.38D decrease) and 1.75D dynamic power
  • Power shift or decrease occurs over a 26mm section in the middle of the lens from 13 mm above to 13 mm below fitting height

Fitting instructions

  • write usual distance/near Rx, near Rx is placed in bottom, top is less plus according to lens design
  • the fitting cross over pupil center for distance PD
  • minimum frame height 16mm depth and 13mm from pupil to frame upper rim
  • 0.75D dynamic power design for adds < 1.50D � 1.25D dynamic power design for adds 1.75D to 2.25D
  • 1.75D dynamic power design for adds > 2.50D

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