Comparison of Early Outcomes of Topo-Guided PRK With Two Refractive Lasers

WCC 2015 San Diego, California

Simon P. Holland MB. FRCSC,FRCS,MRCP 1, 2, A, B, C David T.C. Lin MD FRCSC 1, A, B 1. Pacific Laser Eye Centre, Canada

2. U. of British Columbia, CanadaFinancial Interest: A. Clarion

B. AllerganC. Alcon

Wavelight Allegretto (WA) – Features

400 Hz Gaussian beam profile Pupil based tracker 12 years experience Satisfactory recovery of vision after TE PRK Difficulty with image capture for extreme cases TG PRK – induces myopia due to hyperopic effect Requires refractive compensation – TNT,

Topographic Neutralization Technique

64 years-old female 12 mth post-op

UCVA: 20/300 UCVA: 20/30-

MR: +4.00-3.00x75 Rx: Pl-0.50x30

20/40+ 20/30

CT: 488µm CT: 435µm

Pre OpPre Op 12 mth Pos Op12 mth Pos Op

SubtractionSubtraction

WA TG PRK for Keratoconus

Pre OpPre Op

SubtractionSubtraction

12 mth Pos Op12 mth Pos OpPre OpPre Op

SubtractionSubtraction

Schwind Amaris (SA) – Features High speed excimer laser – 750Hz, 1050Hz

High speed pupil tracker – 1050Hz

Static Cyclotorsion Control (SCC)

Dynamic Cyclotorsion Control (DCC)

Sirius Imaging

Aberration Free (MR)

Corneal Wavefront

Custom Ablation Management :

SA Methods Trans-epithelial TG-PRK with simultaneous CXL

(modified Dresden protocol)

N=68 KC eyes with 6 months follow-up

Maximum refractive error corrected to leave minimal residual stromal depth 300um

Evaluation: pre-operative, 1, 2, 3 and 6 months:

- uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction (MR), topography and keratometry

SA TG PRK for Keratoconus

Pre-operative 6 mth post-op

UCVA: 20/400 UCVA: 20/80+

MR: +1.75-4.50x105 MR:+1.50-2.50x077 20/50- 20/50

SA Treatment Depth: 51.72µm

AW: no autocapture for treatment

12 mth Pos Op12 mth Pos OpPre OpPre Op

SubtractionSubtraction

SA TG PRK CXL for Keratoconus Pre-operative 6 mth post-opBSCVA: 20/25- UCVA: 20/40MR: -7.25-2.00x090 MR: +0.75sph 20/40SA : 63.63 µm

Result: WA for KC

290 eyes completed 12 months or more follow-up

50% (144/290) ≥20/40 UCVA

54% (157) BCVA improved ≥ 1 line

29% (84) improved BCVA ≥ 2 lines

6% (16) lost ≥2 lines.

Mean reduction of astigmatism was 1.71±1.68D

Mean spherical equivalent reduced from -2.78±2.65D to -1.22±2.10D

6%

12%

28%25%

29%

0.0%

10.0%

20.0%

30.0%

% o

f C

ases

LOSS 2LINES OR

MORE

LOSS 1 LINE NO CHANGE GAIN 1 LINE GAIN 2 LINESOR MORE

BCVA Gain/Loss

AW (N=290)

WA: BSCVA Change for KC at 12mth

Result: SA for KC 68 eyes completed 6 months or more follow-up

59% (40/68) ≥20/40 UCVA

91% (62) ≥20/40 BCVA

63% (43) improved BCVA

44% (30) improved BCVA ≥ 2 lines

9% (6) lost ≥2 lines

Mean astigmatism reduction: 1.98±1.75D

Mean spherical equivalent (SE): -3.92±4.02D to -0.40±2.31D

(PreOp SE ranged: -19.00 to 1.88D)

BSCVA Change for KC at 6mthWA vs SA

9%

3%

10% 10%

18%

34%

19%22%

44%

31%

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

Dis

trib

uti

on

%

LOSS 2 LINESOR MORE

LOSS 1 LINE NO CHANGE GAIN 1 LINE GAIN 2 LINESOR MORE

BSCVA Gain/Loss

SA (N=68)

WA (N=95)

p > 0.05

Conclusion of TG PRK with CXL: WA vs. SA

Early results of Schwind TG-PRK with simultaneous CXL

potential as effective treatment for CL intolerant KC patients

SA had almost 60% of the cases had ≥20/40 UCVA and 44%

improved BCVA 2 lines or more at 6 mth

Excellent tracking - Cyclotorsion control and defocus

expect better astigmatism result

Relatively user friendly TG: Customization with multiple options

Imaging for treatment possible in extreme cases