RAY TRACING &

WAVEFRONT ANALYSIS USING

THE TRACEY SYSTEM

Donald R. Sanders, M.D., Ph.D.

Center For Clinical Research

20/10 UNCORRECTED PATIENT

20/10 UNCORRECTED PATIENT

Retinal Spot P S F

20/10 UNCORRECTED PATIENT

20/10 UNCORRECTED PATIENTRef +0.04 + 0.16 X 110 Total RMS = 0.068m

Lower

Higher

5th

Order

4th

Order

3rd Order

2nd Order

Astigmatism Defocus

(Refraction)

Higher

Breakdown of Zernike Terms

-0.5 0 0.5 1 1.5 2123456789

1011121314151617181920

Zer

nik

e te

rm

Coefficient value (microns)

astig.defocus

astig.trefoilcomacomatrefoil

spherical aberration

2nd order

3rd order

4th order

5th order

Root Mean Square

2 2 2 22 0 2 12 2 2 3 .......RMS Z Z Z Z

astig

mat

ism

term

defocu

s te

rm

astig

mat

ism

term

trefo

il te

rm……

GROSS APPROXIMATIONTotal RMS Vs. Visual Acuity

1.0m = 20/20 - 20/25

0.5m = 20/15

0.25m = 20/10

COMPONENTS OF TOTAL RMS

Lower Order Aberrations

Defocus (Sphere)

Astigmatism (Cylinder)

Plus

Higher Order Aberrations

20/10 VISIONRef -0.14 + 0.39 X 168 Total RMS = 0.204m

P S F

LARGELY LOWER ORDER ABERRATIONS

Retinal Spot P S F

99% OF RMS VALUE IS LOWER ORDER ABERRATIONS

(Refractive Error)

Lower

Higher

AFTER SUBTRACTING LOWER ORDER ABERRATIONS

Retinal Spot P S F

REFRACTIVE ERROR

“UCVA” “BCVA”

All Aberrations Higher Order Only

P S F

REFRACTIVE ERROR

“UCVA” “BCVA”

All Aberrations Higher Order Only

REFRACTIVE ERROR

“UCVA” “BCVA”

All Aberrations Higher Order Only

Retinal Spot

CORNEAL BIRTH TRAUMA

“UCVA” “BCVA”

All Aberrations Higher Order Only

P S F

CORNEAL BIRTH TRAUMA

“UCVA” “BCVA”

All Aberrations Higher Order Only

Retinal Spot

CORNEAL BIRTH TRAUMA

“UCVA” “BCVA”

All Aberrations Higher Order Only

COMMON SIGNIFICANT HIGHER ORDER ABERRATIONS

Coma

Spherical Aberration

Trefoil

(T.M.) POST LASIK Complains Of Night Glare

6mm Scan (Undilated)

PATIENT T.M. (OD)6 mm Scan – P S F

“UCVA” “BCVA”

All Aberrations Higher Order Only

“UCVA” “BCVA”

All Aberrations Higher Order Only

PATIENT T.M. (OD)6 mm Scan – Retinal Spot

“UCVA” “BCVA”

All Aberrations Higher Order Only

PATIENT T.M. (OD)6 mm Scan

PATIENT T. M. (OD)Decentered Excimer

COMA

PATIENT T. M. (OD) Vertical

Coma

PATIENT T.M. (OD)EFFECT OF SCAN DIAMETER

(PUPIL SIZE) ON PSFHigher Order Aberrations Only

4 mm 6 mm

UCVA(All Aberrations)

BCVA(Higher Order Only)

PATIENT T. M. (OS)6.5mm Scan – P S F

COMASPHERICAL

SPHERICALABERRATION

HORIZONTALCOMA

PATIENT T.M.NIGHT MYOPIA DUE TO

SPHERICAL ABERRATION

0

0.5

1

1.5

2

2.5

3

4 5 6 6.5

Pupil Size(Undilated)

Amount Of Myopia(D)

0.85

2.49

1.991.66

OS

PATIENT T. M. (OS)Night Myopia Due To Spherical Aberration

4 mm 5 mm

6 mm 6.5 mm

PATIENT T. M. (OS) – P S FNight Myopia Due To Spherical Aberration

4 mm 5 mm

6 mm 6.5 mm

SUMMARY PATIENT T.M.Large Pupils In Dim Light

OD Vertical Coma (Decentration) With Mild Spherical Aberration

OS Horizontal Coma(Decentration) +

Spherical Aberration

PATIENT S. P. Complains Of Severe Night Glare

6.5mm Scan Pupil is 7.0 –7.5mm Undilated

PATIENT S. P. (OD)Severe Night Glare

4 mm 4.5 mm

6.0 mm 6.5 mm

PUPIL SIZE

RMS = 0.261 RMS = 0.407

RMS = 1.83RMS = 1.1

PATIENT S. P. (OD)Severe Night Glare

Pupil Size

RMS = 0.166 RMS = 0.346

RMS = 1.83RMS = 0.656

Higher Order Aberration Only

4mm

6.5mm6.0mm

4.5mm

4 mm 6.0 mm

PATIENT S. P. (OD)Severe Night Glare

Lower

Higher

PATIENT S. P. (OS)Complains Of Severe Night Glare

4.5 mm 5.5 mm

6.0 mm 6.5 mm

4.5 mm 6.5 mm

PATIENT S. P. (OS)Complains Of Severe Night Glare

NOTE: Scale Doubles

PATIENT J. C.Most Higher Order Aberrations – Trefoil, Tetrafoil

J. C. D. D.

S/P RK SURGERY