Myth Busters in Patient Selection for LASIKSteve Schallhorn MD

DISCLOSURES

Consultant to AMOGlobal Medical Director Optical Express

Thin Cornea

“Patients with a central corneal thickness less than 500 microns should not undergo LASIK because they are much more likely

to be abnormal and develop ectasia”

450 460 470 480 490 500 510 520 530 540 550 560 570 580 590 600 610 620 6300

5,000

10,000

15,000

20,000

25,000

Distribution of Preop Central Corneal Thickness thinnest of 3 ultrasonic pachymetry readings

Mean: 549µStdev: 31µ2 STD below: 488µ

81,715 consecutive LASIK– 1 Apr 08 to 31 Mar 09– IL and mech flaps– 2,181 eyes CCT < 500u– 79,534 eyes CCT >=500u

Age Distribution

18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 690.0%

1.0%

2.0%

3.0%

4.0% Cornea <500 microns preop

Cornea >=500 microns preop

Age

Preop Sphere

-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 60%

5%

10%

15%

20%

25%

Cornea <500 microns preop

Cornea >=500 microns preop

Ectasia has been observed in 3 PatientsPt 1 Pt 2 Pt 3

Age 21 23 31

Preop MRx (R/L) -1.25/-1.0 X 070-1.25/-0.50 X 010

-6.5/-1.0 X 055-7.0/-0.50 X 130

-4.0/0.00-5.75/-0.50 X 095

CCT 537 / 527 503 / 505 521 / 527

Flap method Moria Intralase Moria

Est RSB 334 / 329 270 / 272 303 / 281

Preop K 43.5/45 @ 09443.25/45 @ 094

44.0/45.5 @ 13044.25/45.25 @ 080

44.5/45.5 @ 15644.75/45.5 @ 027

Ectasia diagnosis Right eye11 months postop

Right eye18 months postop

Left eye15 months postop

Treatment CXL CXL CXL

Preoperative Sphere

“Patients with more than 3D of hyperopia should not undergo LASIK because they are

much more likely to be unhappy afterwards”

Dissatisfaction as a Function of Treated Hyperopia

≤ 0.50D (1,970)

0.75 to 1.50D (1,173)

1.75 to 2.5D (3,005)

2.75 to 3.5D (1,597)

≥3.75D (580)

0%

5%

10%

15%

1.5% 1.6%2.6%

1.9% 1.9%

Preop Hyperopia

% D

issa

tisfie

d w

ithin

eac

h Ca

tego

ry

Average preop sphere: +2.0 ± 0.9D

Preoperative Astigmatism

“Patients with high cylinder should not undergo LASIK because they are much more likely to be unhappy afterwards”

Dissatisfaction as a Function of Treated Astigmatism

0 to 0.5D (12,430)

1D (7,331)

2D (1,695)

3D (480)

4D (176)

5D or higher

(72)

0%

5%

10%

15%

1.1% 1.2% 1.4% 1.5%2.3%

1.4%

Preop Cylinder

% D

issa

tisfie

d w

ithin

eac

h Ca

tego

ry

Average preop cyl: 0.76D

Patients

Low Light Pupil Diameter

“Patients with >=8mm pupils should not undergo LASIK because they are much

more likely to be unhappy and have visual symptoms”

1M LASIK Dissatisfaction vs Low Light Pupil

4mm (1,703)

5mm (6,831)

6mm (12,937)

7mm (10,963)

8mm (4,519)

9mm (646)

0%

2%

4%

6%

8%

2.0%

1.4%1.2%

1.0% 0.8%

0.1%

Patients

1M LASIK Problems with Daily Activities and Night Driving vs Low Light Pupil

4mm (1,703)

5mm (6,831)

6mm (12,937)

7mm (10,963)

8mm (4,519)

9mm (646)

0%

2%

4%

6%

8%

2.6%

1.8% 1.7%

1.0%1.2%

0.0%

3.1% 3.1% 3.1% 3.1% 2.9% 2.8%

Daily Activities

Night Driving

Patients

Hyperopic Presbyopes

“A +2.50D 60 year old should not undergo LASIK. An RLE procedure will result in

much higher patient satisfaction and less dry eye”

12 Month Age Stratified Random Sample

RLE LASIK 112 pts 159 ptsGender: M/F(%) 41% / 59% 43% / 57%Age (years):

Mean (SD) 60.2 ± 6.2 59.9 ± 4.8)Min , Max 45 to 70 50 to 70

Preop Sphere:Mean (SD) +2.55 ± 0.99D +2.24 ± 0.69DMin , Max +1.00 to +4.50 +1.00 to +4.50

Preop Cylinder:Mean (SD) -0.60 ± 0.47D -0.54 ± 0.43DMin , Max 0.0 to -2.50 0.0 to -2.50

Preop MSE:Mean (SD) +2.25 ± 0.97D +1.97 ± 0.66DMin , Max 0.00 to +4.50 +0.63 to +4.25

Procedure vs. Satisfaction

RLE

LASIK

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

94.6%

93.1%

Satisfied

Neither

Dissatisfied

P = 0.4684

“During the past week, how many times a day do you use artificial tears?”

None One time daily Two times daily

Three times daily

Four times or more daily

0%

20%

40%

60%

80%

100%

73.3%

13.5%

4.4% 4.1% 4.7%

65.5%

14.3%10.3%

3.6%6.3%

LASIKRLE

Refractive Target

“It is best to target a little myopia in presbyopic patients to enhance their

satisfaction”

Mean 1 M Satisfaction vs Postop Sphere

Dominant eye in patients >=40 yrs & patients <=30 yrs

-2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.50

0.5

1

1.5

2>=40 years, emmetropia target

<=30 years

Postop Sphere

Avera

ge S

ati

sfa

cti

on

Score

1,643

1,173

2,5767,338

2,4398,214

1,648

841

1,425

458More

S

ati

sfied

Conclusions

• Analysis of large patient datasets can provide a unique insight to improve refractive surgery

• Patient selection

• Refractive target

• “Myth busters”