ASCRS 08

Changes Of Higher Order Aberrations After Excimer Laser Treatment For Moderate Myopia

by Means of Preoperative Wavefront Aberration Levels using OPDCAT and OATz profiles of Nidek NAVEX system

Uzeyir ERDEM MDSerkan Köksal MD

Cornea & Refractive Surgery Dept. of GMMF

ANKARA TURKEY

The authors have no financial interest in the subject matters of this

presentation

Purpose:Purpose:

Analyzing changes in higher order aberrations (HOA) after Analyzing changes in higher order aberrations (HOA) after two different ablation profiles (OATz and OPDCAT) for two different ablation profiles (OATz and OPDCAT) for myopia using the Nidek NAVEX excimer laser system and myopia using the Nidek NAVEX excimer laser system and comparing the groups for levels of preoperative higher order comparing the groups for levels of preoperative higher order aberrations (HOAs)aberrations (HOAs)

Methods:Methods: We performed analysis of 126 eyes with low We performed analysis of 126 eyes with low

to moderate myopia and myopic astigmatism to moderate myopia and myopic astigmatism who undergone LASIK surgery. LASIK with the who undergone LASIK surgery. LASIK with the both Optimized Aspheric Treatment Zone both Optimized Aspheric Treatment Zone (OATz) ablation profile and OPD-Customized (OATz) ablation profile and OPD-Customized Aspheric Treatment (OPDCAT) ablation profile Aspheric Treatment (OPDCAT) ablation profile was performed in 63 eyes. was performed in 63 eyes.

The preoperative and postoperative UCVA The preoperative and postoperative UCVA and BSCVA,changes were recorded in logMAR and BSCVA,changes were recorded in logMAR units. All patients underwent a detailed units. All patients underwent a detailed ocular examination that included manifest ocular examination that included manifest and cycloplegic refractions, slitlamp and cycloplegic refractions, slitlamp evaluation, ultrasound pachymetryevaluation, ultrasound pachymetry

Material And Method

In both groups parameters have been optimized based on:– pachymetrie, – flap diameter, – And simulated for post operative changes at OATz or

CATZ module of Final Fit software.

NIDEK MK 2000 microkeratome with 130 micron thin flap thickness used for both group

LASIK surgery were done at NIDEK's EC 5000 CXII platform.

Pre-op and post-op examsAfter surgery we made 1st day, 1 week, 1mo, and 3

and 6 month visits. VA (UCVA, BCVA)Subjective+ Objective+Cycloplegic RefractionSlit lamp and Retinal Exam, TOOPD-Scan™

• Autorefractometry+ keratometry• Axial + Instantaneous topographic maps• OPD + Internal OPD maps• Refractive Map• Total Wavefront + HO aberration maps• PSF + Zernike Graph • Mesopic and fotopic pupillometry

WF analysisWF analysis Analysis of Wavefront Aberrations: Three

measurements with OPD Scan wavefront aberrometer from each eye was evaluated using software that follows the standards for calculating and reporting the optical aberrations of eyes as proposed by Thibos and associates

1) Root-mean-square (RMS) of HOA from the third to eighth orders; 2) RMS of the total spherical aberration (TSA; square root of the sum of the squared coefficients of C4

0, C60, and C8

0); 3) RMS of total coma (TC; square root of the sum of the squared coefficients of C3

-1, C31, C5

-1, C51, C7

-1, and C71); and

4) RMS of total trefoil (T3F; square root of the sum of the squared coefficients of C3

-3, C33, C5

-3, C5 3, C7

-3, and C73).

5) RMS of total tetrafoil (T4F; square root of the sum of the squared coefficients of C3

-4, C34, C5

-4, C5 4, C7

-4, and C74)

6) RMS of total high astigmatism (THiAst; square root of the sum of the squared coefficients of C3

-5, C35, C5

-5, C5 5, C7

-5, and C75)

The parameters analyzed The parameters analyzed included included

Statistical AnalysisStatistical Analysis

All statistical data were analyzed using the SPSS 11.0 (SPSS Inc, USA) statistical software.Descriptive statistical analyses of parameters and standard deviations were calculatedStatistical differences were considered significant when P<0.05

ResultsResults

126 eyes (63 patients) Ages 29±3.6 in women, 27±4.1 in men, there were no difference related age and sex between groups.

Dr Üzeyir ERDEM 11

Safety

No lines of BCVA have lost in two group No lines of BCVA have lost in two group after surgeryafter surgery

No serious flap complications

ResultsResults WFA WFA

OATz: −5.14+/-1.59 DOATz Pre Op 3rd mo Post Op PMean RMS HOA 0.40±0.15 µm 0.45±0.14 µm 0.017T.Coma 0.17±0.10 µm 0.24±0.12 µm 0.001T.SA 0.09±0.07 µm 0.19±0.12 µm 0.001T. trefoil, decr. 0.27±0.13 µm 0.23±0.11 µm 0.004

OPD CAT: −4.40+/-1.53 DMean RMS HOA 0.19±0.17 µm 0.25±0.15 µm 0.001T.Coma 0.19±0.17 0.25±0.15 µm 0.003 T.SA 0.10±0.08 µm 0.16±0.10 µm 0.001T. trefoil, decr. 0.25±0.13 µm 0.24±0.17 µm 0.672

HOAs, TC, TSA increase HOAs, TC, TSA increase isis significiant significiant

Dr Üzeyir ERDEM 13

RMS value changes of OPD CAT and OATz Group

OPDCAT HOAs RMS values increase at 3rd Mo.

Pre- Op HOAs RMS < 0.3 RMS increase 88%

Pre- Op HOAs RMS >0.3 HOA increase 4.3% (p=0.001)

OATz HOAs RMS values increase at 3rd Mo.

Pre- Op HOAs RMS < 0.3 RMS increase 92%

Pre- Op HOAs RMS >0.3 HOA increase 14.5% (p=0.001)

Dr Üzeyir ERDEM 14

Refractive Outcome 1st Mo

Dr Üzeyir ERDEM 15

Refractive Outcome 3rd Mo

Dr Üzeyir ERDEM 16

OPD CAT 3rd Mo

0

2

4

6

8

0,00 2,00 4,00 6,00 8,00

Attempted Change in Spherical Equivalent

Ac

hie

ve

d C

ha

ng

e in

SE

Dr Üzeyir ERDEM 17

OATz 3rd Mo

0

2

4

6

8

0,00 2,00 4,00 6,00 8,00

Attempted Change in Spherical Equivalent

Ac

hie

ve

d C

ha

ng

e in

SE

Dr Üzeyir ERDEM 18

Stability of Refractions

Postop Follow-up

3 ay1 ay2 hfPreop

SE(D

)

2

0

-2

-4

-6

-8

Postop Follow-up

3 ay1 ay2 hfPreopSE

(D)

2

0

-2

-4

-6

-8

OPD CAT OATz

ResultsResults

LASEK with Nidek NAVEX platform with LASEK with Nidek NAVEX platform with the OATz the OATz and OPD CAT and OPD CAT ablation profile ablation profile was safe and effective in correcting was safe and effective in correcting high myopic astigmatism comparing to high myopic astigmatism comparing to other high myopia treatment optionsother high myopia treatment options

WF aberration changes similar WF aberration changes similar for for low low andand moderate myopia moderate myopia

HOA increased in both group but HOA increased in both group but increse amount is far less in increse amount is far less in high(>0.3 high(>0.3 µm ) RMS) RMS group. group.

Conclusions:Conclusions:

• The comparison between LASIK custom (OPD CAT) and conventional (CATz) shows that there is a tendency of improvement on spectacle correction, and better predictability on the Custom treatment group.

• Quick dedection of irregularity with OPD-Scan and the correction of corneal irregularities and aberrations with Final Fit software, and 1 mm multipoint ablation module of NIDEK laser looks promising for better results.

Dr Üzeyir ERDEM 21

Conclusions

The amount of increase in postoperative higher order aberrations in both groups was acceptable after myopic LASIK surgery. Nevertheless, the eyes with low amounts of preoperative aberrations showed a marked increase in aberrations following wavefront guided treatment; therefore, wavefront treatment may not be beneficial for all eyes.

Longer follow up and larger series would be needed for better understanding.