Prescription Vivar Flashcards
Single vision 1
RE Sph — cyl -1.00 axis 10 °
LE sph -0.25 / cyl -0.5 axis 15° prism 4 base 90
RE = No power
LE = needs to be to 2 decimal places
90 = 360 Degree notation = base up
Axis has °Sign
BS 2738 - writing of RX + BVD - refer to prescriber
Prism- standard notation - base direction
Can be done by decentration C= P/F
Surfacing - thick @ base Image displaced towards Apex
Split Prism RE+ LE - RE 2 Prism Down LE 2 Prism up
fresnel Prism - Temporary - back surface,PVC, 1mm thick, up to 30D of Prism,Reduce VA by 2 lines = Amblyopia
Single vision 2
RE Sph = +3.00DS
LE Sph =+3. 50DS prism 3 base 360
Age 6
HES RX
Hyperopia - long sighted - struggles with close work
Prism Base out (360 Draw Prism notation)
eye turns in - ESO - phoria cover test, Tropia always there
never split Prism for kids
calc prism by decentration = c = P / F (3.50 / 3.00) = 0.86cm = 8.6mm out
calc MSU lens Size 44mm=ED+(2xdecen)+2mm=44+(2x8.6)+2= 64mm
other option- Surfaced - Thickest Part @base 3 out = Temporal edge
Padeatic frame fit checked @ frame dispense + collection
facial features - low crest / flat Projection / big Apical radius
Constant wear/ critical period upto Age 7/ Improve VA + binocular vision
Trivex More Impact resistant - V-Value 43-45 n= 1.53 - less Chromatic Aberation
Single Vision 3
RE Sph +2.00DS
LE Sph +5.00DS
Amblyopic
RE - non aspheric. LE Aspheric 1.67/ 1.74
Difference in Power - Anisometropia - Gross: 2.00 or more,Differential Prism @ Near,Vertical diplopia @ near ( Image on top of other) .
Aniseikonia - difference in retinal Image Size,blurred Vision,causes nausea,dizziness,headaches caused by spec mag
Amblyopia Difference of 2 lines or more of VA (LE: higher power =weaker Eye)
pv ( only vert) P= CF = 1.00 X 2.00 = 2 Prism up ,1.00 x 5 = 5 prism up differential = 3 up LE
BS tolerance = 1 vert differential Prism
Solutions - Slab on. add base up - least positive eye minImum 2 up (lower limbus)
Drop Spec’s - dropping OC = no prism - dispense Seperate pair OC lower
contact lens BVD = O SM 1
Single vision 4
RE - 4.00/ -0.25 X 45
LE - 4.25 / -0.50 X 135
Sports Wear
Myope - Compound Astig when transposed ( Sign of Sphere Stays Same)
oblique cyls - 90° to each other -
focimeter current Spec’s to check as not normal but can happen
Sport - which Sport - Trivex Safer V - value 43-45 n- 1.53
Single vision 5
RE - -10.00/ -2.00×90
LE - 9.50 / - 1.50 x90
BVD 12mm
CF VA 6/12. 6/ 9
complex as 10D or more
BS 2738 for BVD
CF @ 1mm
HM @ 1 mm
LP = light perception / light on / off _ low vision
NLP -Blind
asked to calculate far Point 1/ -10 = 10cm when specs off
low VA due to speg mag
Mini bevel glazed near front thickness at back
fitted with CL to improve VA SM=1
Reduced BVD - compensate RX = increase field of view
Lens 1.76 BI AS V=30 (plastic)
1.74 AS V=31 (plastic)
1.67 AS V=33(plastic)
1.9 non AS (glass)
1.8 AS V =35
1.7 Non AS V=40
Measure mono CD / vert height - no prismatic effect
drop OC 2mm of frame tilt 2Degrees
Concave lentic- reduced FOV, Ring scotoma (30/34 Aperture)
Blended Lentic. rodenstock lentilux max edge 4mm up to -25D
Single vision 6
RE +4.00DS
LE +4.50DS
Best form lenses
Best form reduce 5 problems-
Curvature- induced by base curve
distortion- base curve -ve barrell +ve pinchusion
oblique astig (blurriness around image) AS eliminate oblique astig Tilt & heights
transverse chromatic aberration
Coma (draw pic see notes)
Lens recommended - 1.74AS elimates oblique astig
single vision 7
Reading area of RX
RE +3.00DS
LE +3.00DS
(low vision)
Requires 3x magnification
Low Vision
SVN +hand held mag
steady eye strat
Large frame
non AS - want spec mag
magnifier start on page move away
angle poise lamp over shoulder
MAR
Solution 2
LVA,galilean telescope unit LOw vision clinic at HES
solution 3
Specs incorporate mag one eye supressed
RX +3.00D
F= SM x 4 F= 3x4 =+12.00D 12=3= +15.00D R&L specs include mag dispense lenticular convex 42mm bigger aperture = more FOV
