Trial Frame
 Trial frame uses:
o Demonstrate a new Rx or changes in sphere, cylinder, and/or axis of
current Rx
o Also used for emerging presbyopes or add changes
o Latent hyperopes
o Prisms
o Decreasing minus for an over-minused myope
o Compare new Rx to current Rx before ordering
o If patient did not bring current Rx (used in preliminary testing)
Temple Length Adjuster
Nose Pad Height
Vertex distance
Cylinder Axis
PD
Pantoscopic Tilt
Axis Lock
 Adjustments
o Top Knob: adjusts vertical alignment via the nose pad
o Center Knob: adjusts vertex distance via nose pads (moving in/out)
 Measure vertex distance if high Rx
 Measured from most posterior lens well **zero is VD=15mm*
o Side Knobs on center bar: adjusts monocular PD
o Side Knob on eyepiece: adjusts axis of cylinder
o Knob on temple: adjusts pantoscopic tilt
o Temples: adjust length
 Placement of Lenses
o Strongest sphere: back well
o Cylinder: most posterior of anterior wells
o Auxiliary Lenses (prism, additional sphere or cylinder): remaining anterior
wells