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L11 Optometers & Wavefronts - Coggle Diagram
L11 Optometers & Wavefronts
optometer
badal optometer
subj, fixed plus power lens
make img coincident w far point
adjustable, visible light, close to real life
autorefractor
scheiner autorefractor
scheiner w IR LEDs
at least 3 meridians, sph-cyl sine-squared function
co-axial alignment imp, irreg cornea unreliable
retinoscopic autorefractor
photo light reflex
pupil size, WD, angle, size of flash, direction + speed -> power
grating focus autorefraction
grating targ on retina
light levels of ret img measured
3 meridians, max contrast -> power
image quality analysis
grating focus autorefractor
longitudinal chromatic aberration
use IR -> better transmission + reflectance
built-in correction
diff b/w IR + VL -> LCA
IR pupil size not affected, but penetrate deep
instrument myopia
over-accom
built-in fogging, open field, relaxing targ
other
preference b/w 1/2/AR
noncyclo AR tends to over-minus but more acc in cyclo
subj most comfort, OF AR least comfort, all sim results
better AR or aberrometry
AR-SR stronger than OPD-SR
direct prescription from AR/OPD discouraged
biased advertising
best evid via RCT
consider non-optical factors
Rx just numbers
opportunities
WF-guided laser ablation
correct HOA, minimise laser-induced ab
customised
greater precision
unanswered questions
monochr OPD in polychr world
accuracy factors
minise all ab or just selected
what is good enough
aberrations
aberrometer
wavefront aberrometry
wavefront reconstruction
WF shape measured at exit pupil plae
total ocular WF error -> WF map
wavefront analysis
maths: zernike, taylor, fournier
coma, sph ab, obl astig, field curve
hartmann-shack aberrometer
HS wavefront reconstruction
outgoing WF, IR/visible on retina
lenslet w slope
beam displacement -> ab measure
measure both LOA + HOA
measures light deviation/WF reflection from path
diff b/w input + output -> ab
ongoing vs ingoing, most exp than AR