Dispensing Final Flashcards
Which factor is normally NOT considered essential in fitting th progressive add
Specificying the nasal rotation of the ptrogressive channel
The fitting cross for a general purpose ptorgressive addition lens would be fitted higher than specified by the lens manufacturer in what condition
The progressive is used to inhibit accommodative esotropia in children
when children are fin with ptrogressive addition lenses, yet still have the ability to accomodate just as other children do, the fitting cross is usually fit
4mm above pupil center
Children fitted with progressive addition lenses should not wear those lenses for sports or play ? T or F
False
Progressive lens fitting crosses should be set lower for the first-time wearer to aid in adapting to the lenses T or F
False
Prism is verified at a different locationo n the ptrogressive add lens from where the distance Rx is verified? T or F
True
The fitting cross is at the major reference point? T or F
False
A synonym for major reference point is?
prism reference point
If a progressive lens design changes as ad power changes, the lens is called a mulitdesign lens? T or F
True
Adaptation to progressive addition lenses involves changes in the respective eye and head movements used in fixation
True
Although all of the factors listed below are important in the fitting of ptrogressive addition lenses, which factor has the most influence on wearer satifaction
fitting accuracy
In practice the power of the near addition is seldom measured when verifying progressive lenses
True
What method for viewing the hidden markings on a progressive addition lens is NOT suggested
Hold the lens so that its surface may be viewed in a mirror by reflected light
A frame has been selected for a progressive addition lens wearer. Some of the parameters of the frame and frame fitting are listed…..What would be considered problematic?
The laboratory order form specifies a binocular distance PD of 65
The frame is an aviator shape
When a wearer does come back with a compleain, the most straighforward wat to check for possible problems is to first put the progressive markings back on the lenses and see if they are correct in relation to where they shoul be when the rx is worn? T of F
True
Unwanted peripheral cylinder power in a progressive add lense, increases how?
Increases as the add power increases
Compared with a soft design, a hard design usually provides a wider area of high visual acuity in the distance portion of the lens. T of F?
True
Progressive power can change from distance to near zones in either a rapid or slow fashion. If it changes in a rapid fashion, then what will not occur?
The near zone is generally smaller
Distance and intermeidate and near zone widths influence each other. When one zone is made larger or wider, teh other two zones will become narrower or smaller? T of F
True
Contour plots record the surface elevation for the front surface of a ptrogressive addition lens. T or F
False
What is not demonstrated by contour plots
The expected increase or decrease in chromatic abberation throughout the lens
What lens design is more likely to have higher amoutns of peripheral astigmatism
Hard design
Would a prgoressive add lens with a spherical upper front surfaces be more likely hard or soft?
Hard
Is a progressive addition lens specifically designe for frames with a narrow B dimenstion more likely to resembel a hard or soft design
Hard
Is a presbyoopic emmetrope who is used to crystal clear distance vision more likely to complain about a progressive addition lens with a hard or soft design
soft
Whihc lenst type does NOT requrie free-form type of lens generating to make the lens
Progressive made as semifinished lenses and completed in labratory
Position of wear lenses are able to correct or comepensate for all but which of the following?
It can correct everything vertex distance panto change base curve induced cyl/sphere
near variable focus lenses have a powere degression..Degression is??
The range in power of a variable focus lens from the total near power of the lens to the power found at the top of th lens
Near variable focus lenses are used for small office environments, and all have 50% of the add poewr in the upper portion of the lens? T of F
False
Near variable focus lens design will be used for presbyopes with all differnt amounts of add power. How many power ranges do near varialbe focus lenses have for each particular brand?
1, 2, 3…as man as there are add powers
Suppose a variable focus lens made by a certain manufacturer comes with a recommended power range of 1.25 fore weares who have a +2.25 add. This particular wearer has a distance correction of -0.50 +0.75 x 090 for OD and OS…and an add of +2.25.. What pwere would be verified in the upper portion of the lens?
+0.50 +.75 x 090
A near variable focus lens has a +1.25 -0.50 x010 power in the upper portion of the lens. It has a power of +2.75 -0,50 x 010 in the lower portion what is the degression (power range) of the lens?
+1.50
Near variable focus lense are all fit exactly like standard progressive addition lenses, measuring monocular PDs and placing the fitting cross under the pupil?
False
No occupational progressive lenses meant for small offices and computers come with distance powers in the top of the lens-onlyintermediate powers? T or F
False
Usint the rule of thumb for prism thinning of progressvie addition lenses how much prism thinning would be expected for the follwoing
+3.00 -0.75 x 090 add +2.25
-3.00DS ad +1.00
1.5pd BD
None required
+3.00 -0.75 x 130
add 1.50
what prism thinning should be giving?
0.75pd
For progressive addition lens how much yoked BD should be given
-3.50 -0.50 x 180
add +2.00
none
Lenses are surfaced in a finishing Lab? T or F
False
which type of lens has the same power over the entire lens
Single vision lens
What term is a synonym for a finished lens?
Uncut lens
A frame tracer is often used in conjuction with?
a lens blocker
Of the steps in lens fabrication, which process occurs last?
Edging
What is the proper steps in the edging process?
Find lens axis and MRP location, Centration, Blcoking, Edging
When spotting a single vision lens for edging in reference to edged lense orientation the lensmeter ing dots will be on?
the cylinder meridian
Whigh point should always appear either exactly in front of (or somewhat below) the wearer’s pupil
geometric center
If there is no prescrived presim in the prescription, what point will not be the same?
NRP
Horizontal pattern size is measured horizontally through the central hole in the pattern? T or F
False
For a plano cylinder, light passes through the ( ) meridian undeivated
Axis