ENTER RELEX-GOODBYE EXCIMER Dr. Rupal Shah

Clinical Director, New Vision Laser Centers, India

www.drrupalshahlasik.com

EXCIMER LASER

Technology has been around since at least 20

years

Stable Technology

Excellent results (>95% of all eyes are within +/-

0.5D)

Ability to customize treatments

High Patient Awareness and Acceptance

CONVENTIONAL LASIK

Mechanical Microkeratome to create a hinged flap

Flap is lifted to one side and excimer laser ablation is

carried out

In excimer Laser ablation a lens is ablated from the

cornea, equivalent to the correction achieved

Lens material is removed in the shape of a gas plume

from the corneal surface

FEMTOSECOND LASER

Well established Safety Profile for making LASIK

Flaps

Several Advantages “Locked In” Flap

Fully Sterile

Tight control of Flap thickness

Thin Flaps possible

More Predictability and better complication profile relative to

mechanical microkeratome flaps

Preferred choice for making LASIK flaps

RELEX

Uses only the femtosecond laser for completing the entire

LASIK procedure

No need for an excimer laser

Possible only with the VisuMax Laser from Carl Zeiss

Two Procedures

FLEx=Femtosecond Lenticule Extraction

SMILE-Small Incision Lenticule Extraction

Surgical steps of the ReLeX Procedure

1

2

3

WHY RELEX?

STABILITY OF THE LASER

Excimer Laser is a gas based laser. Even after

many improvements, it is not as stable as a fiber

based femtosecond laser

In a study we did, our MEL 80 excimer laser

required about six interventions in the year ended

February 2011 (including gas bottle changes)

Our VisuMax Femtosecond Laser required only two

interventions (of which one was for software

upgradation)

CORNEAL RESHAPING WITHOUT ABLATION

An excimer laser performs photoablation

The photoablation rate increases linearly with

fluence beyond a certain threshold

Excimer Laser fluence and photoablation rate gets

influenced by various factors –corneal hydration

levels, humidity levels, the presence of organic

vapors, the depth of ablation

This results in a scatter, especially for the treatment

of high myopia

RELEX

Uses cutting instead of ablation

A binary process instead of linear

Much less influence of any external factors

Reflected in the tremendous accuracy achieved,

even in the first 1500-2000 eyes treated worldwide

Results are especially interesting for high myopia, a

group in which excimer lasers don’t fare as well

RESULTS OF REFRACTIVE CORRECTION

USING RELEX WITH A 500 KHZ VISUMAX

1% 1%1% 2%

2% 2% 3%

94%97%

95%98%

1% 1% 1% 1% 0%0%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

CZ

M-A

pp

lica

tio

n P

uja

ra

-1,0

1 to

-2

-0,5

1 to

-1

+- 0

,5

+0,5

1 to

+1

+1,0

1 to

+2

Refractive outcome - Percentage within Attempted

1 m (410) 3 m (377)

6 m (261) 1 y (64)

month (eyes)

SCATTER PLOT OF RELEX WITH A 500 KHZ

LASER (AT 3 MONTHS)

Scatter: Attempted vs. Achieved SEQ 'PREDICTABILITY' 377 eyes

y = 0.99x + 0.02

R2 = 0.98

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Attempted delta SR equiv. [D]

CZ

M-A

pp

lica

tio

n P

uja

ra

Achieved [D]

overcorrected

undercorrected

RESULTS OF RELEX FOR HIGH MYOPIA (>-5D

UPTO -10D)

RELEX AND INFLAMMATION

Total amount of energy input into the eye with

ReLEx is less than with Femto LASIK

Results in less inflammation and higher stability of

the treatment

RELEX-STABILITY AFTER TREATMENT WITH A 500

KHZ LASER

Achieved Correction SEQ over Time 'STABILITY'

-0.03-0.03-0.02-0.02

-4.43

422 410 377 26164

-7.00

-6.00

-5.00

-4.00

-3.00

-2.00

-1.00

0.00

1.00

pre op 1 m 3 m 6 m 1 y

CZ

M-A

pplic

ation P

uja

ra

STABILITY AFTER RELEX FOR THE TREATMENT

OF HIGH MYOPIA (>-5D)

Time

-6.41

0.140.07 0.08 0.06

4383113118123-8.00

-7.00

-6.00

-5.00

-4.00

-3.00

-2.00

-1.00

0.00

1.00

pre op 1 w 1 m 3 m 6 m

POTENTIAL FOR MINIMALLY INVASIVE

TREATMENT

One can easily remove the lenticule from a 3 mm

incision. We are working on techniques to reduce

this to less than 1.5 mm

VIDEO

SMALL INCISIONS

No risk of flap displacements (There is a cap. There

is no flap!!!)

Small Incision results in minimal cutting of corneal

nerves – less dry eyes, smaller reduction in corneal

sensitivity

Less discomfort for the patient for a smaller period

Possible better biomechanical stability relative to

Femto-LASIK

INDUCTION OF ABERRATIONS

Excimer lasers suffer from peripheral fluence loss

Fresnel reflection losses at a high angle of incidence

Increase in spot size in the periphery

Leads to an increase in spherical aberrations

Minimized by newer ablation profiles

However, with ReLEx, this problem is essentially

not there

Should lead to less induction of spherical aberration

In our study, there was an induction of less than 0.12

microns of spherical aberration (5 mm pupil)

WORKFLOW IMPROVEMENTS

No need to change stations

No need to keep placing and removing the

speculum

In a study we conducted,

SMILE (2 Eyes) took an average of 12.9 minutes

Femto LASIK (2 Eyes) took an average of 21 minutes

At our volume, doing ReLEx on all patients would

result in a net saving of 120 hours a year, or half an

hour every working day

PATIENT ACCEPTANCE

Patients really like the idea of a flap less procedure

without the pain and slow visual recovery of surface

procedures

In my experience, ReLEx is an easier “sell” to

patients than Femto-LASIK

COSTS

Only one laser needed instead of 2

Capital cost is reduced by nearly 50%

Consumables of only one laser

Maintenance contract of only one laser

SO WHEN IS AN EXCIMER NEEDED

Wavefront Guided Procedures (< 5% of a normal

refractive practice)

Retreatments (< 1% in ReLEx procedures- In over

1000 eyes treated, I have actually retreated only 3

eyes)

Hyperopia (Latest results of ReLEx for Hyperopia

are quite encouraging)

GOODBYE EXCIMER Enter ReLEx

drrupalshahlasik.com