Design of Occupational Lenses Progressives / Alternative Multifocals
Jon Torrey VP, PRIO/Computer Vision Essilor of America
Background
Fundamental Shift in Use of Vision Past: Primarily distance vision Today: Intermediate/ near
Computer Use by Presbyopes Continues to increase: Number of individuals Hours/week/individual
Computer Use by Presbyopes Driven largely by specific applications: Email Social networking sites
Computer Use by Presbyopes Baby boomers: 1st generation to use computers through majority of career Continuing use into retirement
Computer Use by Presbyopes Nature of Presbyopia: Loss of Accommodative amplitude Necessitates a reliance on lenses to enable clear viewing at intermediate and near distances
LCD / Widescreen Displays Rapid acceptance of technology has compounded the need for improved intermediate viewing, and specifically wider intermediate areas within lenses
Optometrists’ Quotes “Up until now I basically gave up on these patients that have visual fatigue symptoms. I didn’t feel like I had anything to offer them in my clinical arsenal.” “There really isn’t enough products for us to pick from for dealing with some of these accommodative disorders that we’re identifying.” “The progressives don’t cut it for those patients who spend great deals of time on the computer.”
Current Lenses: Design Limitations
Current Lens Designs: Limitations Given nature of intermediate viewing at 50 – 70 cm, current lenses available are less than optimum: SV – when set up for intermediate distance, no facility for more plus at near No clear viewing at full distance
Current Lens Designs: Limitations Bifocal – when set up “normally,” no clear area for intermediate distances Typical response is for wearer to tip head back and lean forward
Current Lens Designs: Limitations Bifocal – when set up for intermediate distances, with a small add for near viewing, wearer sacrifices clear distance vision
Current Lens Designs: Limitations General-purpose PAL: intermediate area is 3rd priority, after Distance and Near Intermediate area is narrow and located below center, requiring head tipping to see desktop screen clearly
Current Lens Designs: Limitations Near Variable Focus lenses: significant step forward in visual flexibility and comfort Many wearers still request full distance vision
Research – Design Preference Patient preference in lenses for computer use, comparing general-purpose PAL with Near-Variable Focus design 97% of subjects preferred NVF design (Essilor, 2004) 81% of subjects preferred NVF design (PRIO, 2004) 1) Source: Essilor of America – Lens Comparison Survey - October ‘04 (40 subjects ages 45+) USA 2) Source: PRIO Corporation – Lens Comparison Survey - August ‘04 (40 subjects ages 45+) USA
Computer/Intermediate Lens - Ideal Design?
Ideal Lens: Design Factors Feature set for ideal “occupational” lens for extended intermediate and near viewing would of course be a tradeoff between a variety of factors: Vertical placement of intermediate power Width of intermediate area Slope of power curve
Ideal Lens: Design Factors Percentage of prescribed add power delivered at fitting cross Corridor length Area of full distance power at top of lens Minimum B measurement required
Ideal Lens: Delivery Factors Just as important as the optical design factors are the “delivery” issues: Rx prescribing requirements for Doctor (distance, intermediate, or near Rx?) Fitting parameters for dispenser Ordering information needed by lab
Essilor ComputerTM An Ideal Compromise
Essilor ComputerTM Design Maximize intermediate area, both horizontally and vertically
Essilor ComputerTM Design Accommodate ergonomic needs of majority of wearers Screen ~60 cm ~4° ~30° ~30 cm ~45 cm Keyboard
Essilor ComputerTM Design AScalc [WNT] 2 DEGAUDED Deliver 60% of prescribed add at Fitting Cross
Essilor ComputerTM - Benefits Comfortable viewing at intermediate, near, and distance Wide clear intermediate area to see the entire screen (or other intermediate object) Some viewing at distance, to see across office No more head tipping
Essilor ComputerTM - Fitting Order just like normal progressive Dot center pupil Monocular Distance PDs 15 mm minimum Seg Ht 30 mm minimum B measurement Rx Range: -6.00 to +7.00D cyl to -4.00
Essilor ComputerTM - Uses Besides computer viewing: Any Intermediate / near activity Sewing Carpentry Auto repair Cooking Optometry Painting Scrapbooking
Essilor ComputerTM – Patient Wearing Trial
EC Lens – Patient Preference Wearers satisfied with current vision at computer PAL: n =33 1) Source: Essilor International – EC Lens Wearing Trial - October ‘05 (89 subjects ages 40+) UK, France
NOT satisfied with current vision: n = 30 EC Lens – Patient Preference Wearers not satisfied with current vision at computer NOT satisfied with current vision: n = 30 1) Source: Essilor International – EC Lens Wearing Trial - October ‘05 (89 subjects ages 40+) UK, France
Questions? Jon Torrey 503-781-8460 jtorrey@essilorusa.com Thank You! Questions? Jon Torrey 503-781-8460 jtorrey@essilorusa.com