ENTER RELEX-GOODBYE EXCIMERDr. 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

tion

Pu

jara

-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

tion

Pu

jara

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

422 410 377 261 64-7.00

-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

atio

n P

ujar

a

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 EXCIMEREnter ReLEx

drrupalshahlasik.com