Everything a General Practitioner needs to know about Laser Vision Correction

1. Ophthalmic GP Education Evening
10th July 2014
Anil Arora

2. What is refractive surgery?
A group of outpatient procedures used to alter how the
eye focuses light rays on the retina, thereby improving
vision and reducing dependence on glasses and
contact lenses.
Refractive surgery
procedure on the cornea

3. What is refractive surgery?
Most refractive surgery is performed on the cornea and
affects only the front of the eye.
In some cases, refractive surgery procedures don’t
reshape the cornea; instead, the eye’s natural lens is
either replaced or enhanced by an implantable lens
that helps correct vision.

4. Refractive Surgery
Laser vision correction
LASIK
ASLA (Advanced surface laser ablation) ( Formerly PRK)
Lens based surgery
Cataract surgery (patient’s own lens cloudy)
Clear lens exchange (patient’s own lens clear)
(also known as a refractive lens exchange)

5. What is laser in-situ
keratomileusis (LASIK)?
Outpatient refractive surgery used to treat nearsightedness
(myopia), farsightedness (hyperopia) and astigmatism.
LASIK involves:
creating a thin, hinged flap in the cornea, either with a
femtosecond laser or a mechanical blade, which is then gently
folded back to expose the internal structure of the cornea;
using an excimer laser to precisely sculpt the exposed cornea
to correct the refractive error; and
immediately repositioning the thin flap following the laser
application and allowing it to heal naturally.

6. LASIK
For myopia, the corneal tissue is removed centrally in a
lenticular (lens-like) pattern, thereby flattening the central
cornea and reducing the eye’s focusing power to correct the
refractive error.
For hyperopia, the corneal tissue is removed around the
edges, thereby steepening the central cornea and
increasing the eye’s focusing power.
For astigmatism, the corneal tissue is removed in a precise
elliptical pattern that steepens the cornea where it is too
flat and flattens the cornea where it is too steep, thereby
accurately correcting the refractive error.

7. LASIK and Epi-LASIK
A preoperative eye exam includes measurements to give
the surgeon the necessary information to perform the
procedure and to see if the corneas are suitable.
Pre-operative screening and assessment with the staff
Slit lamp exam

8. LASIK and Epi-LASIK
Corneal topography: mapping the surface details of the cornea
Corneal keratometry: measurement of the form and curvature of the
cornea
Corneal pachymetry: measurement of corneal thickness
Aberromerty
Measurements for lens based surgery
Assessment of ocular dominance
Trial of monovision – with glasses in a frame or with contact lenses
Preoperative screening and assessment with the staff

9. LASIK and Epi-LASIK
Surgeon goes through the results obtained by the staff
and rechecks the results
Discusses the patient’s needs and expectations
Attempts to provide the best solution for a given patient
based on age, patient’s lifestyle requirements, corneal
status, presence or absence of a cataract.
Tries to provide a REALISTIC idea of what happens
during the procedure and what to expect afterwards and
what sort of vision result is obtainable.
Discussion of potential risks and complications and
their management
Preoperative assessment with the surgeon

10. CRS-Master
Diagnostics
CRS-Master
Treatment Planning
OcuLign
Eye Registration
VisuMax Flap Cut MEL 80

11. LASIK and Epi-LASIK
Prior to the LASIK procedure, the eye(s) are prepped for surgery
and treated with anesthetic drops.
On the day of surgery!

12. Bladeless LASIK
How is bladeless LASIK performed?
A femtosecond laser is used to create a thin, hinged flap of corneal tissue.
This has, in most modern laser vision centres, replaced the mechanical
motorised blade (microkeratome). The laser is far more precise.

13. VisuMax Femtosecond System
The femtosecond laser
incision
• A femtosecond is one million billionth of a second
• High intensity laser light induces a submicron tissue disruption
• A layer of narrow tissue disruption spots create a tissue incision
• A flap incision consists of the stromal flap bed and the sidecut
• Remaining tissue bridges can be separated mechanically

14. LASIK and Epi-LASIK
How is LASIK performed?
Once the flap is lifted to one side . . .
. . . laser energy from an excimer
laser is applied for a few
seconds to a minute or so to
reshape the exposed surface of
your cornea.

15. Excimer Laser
-Excimer laser technology was developed in the late '70's by IBM.
-Designed as a tool to etch very high density circuit patterns in
computer chip manufacturing process.
The fact that excimer laser
treatment does not injure 0r
distort adjacent tissue,
combined with the precise
accuracy of sculpting, makes
it a very effective tool for
etching computer chips, and
an incredibly delicate and
accurate instrument for
correcting vision.
Human hair
sculpted with an
excimer laser

16. LASIK and Epi-LASIK
The tissue flap from the cornea is placed back into its original
position, where it adheres naturally, protecting the treated area and
restoring the smooth front surface of the eye.
How is LASIK performed?

17. Considerations for LASIK surgery
LASIK is a less invasive procedure than intraocular
surgery.
The procedure and visual recovery are quick, and
discomfort is typically minimal.
Corrects up to about -10 dioptres of myopia and +5
dioptres of hyperopia as well as up to about 5 dioptres
of astigmatism.

18. Considerations against LASIK
surgery
LASIK is not recommended for patients with thin corneas.
LASIK is not recommended for patients with keratoconus
(irregular protrusion of the cornea), or other corneal
diseases.
LASIK is not recommended if myopia, hyperopia or
astigmatism is beyond the approved parameters of the
procedure.
LASIK is not recommended for patients with significant
systemic medical illnesses that may severely affect healing.
LASIK is not recommended for patients with severe dry
eye.
After LASIK, you may be restricted from certain
occupations.

19. A word about ASLA/PRK
ASLA (advanced surface laser ablation) – was formerly known as PRK
(photorefractive keratectomy) involves scraping away of the top layer
of cells of the cornea after loosening them with an alcohol solution
and then applying the excimer laser directly to the cornea. Contact
lens worn for about 5 days.
NO CORNEAL FLAP.
Painful for 2-5 days and slower healing than LASIK. Drops may be
needed for up to 2-3 months post-op.
Final result usually same as LASIK
Used at LVCCC in patients with corneas too thin for LASIK. Our 2012
analysis showed 94% of our procedures were LASIK and 6% were
ASLA.
Some centres ONLY perform ASLA and not LASIK. It is often
promoted as “incision-free” laser vision correction

20. Risks and possible side effects of LASIK surgery
• Overcorrection or undercorrection (with a possible
need for retreatment – “enhancement”)
Reduced contrast vision (sharpness)
Poor night vision
Glare, halos, starburst, ghosting of images
Corneal infection
Light sensitivity
Dry eyes
Flap complication (either during or following surgery)
Regression of initial surgical effect

21. Options for reducing spectacle dependence
If a patient is aged between 21 and about 40 years old
they can have laser vision correction to both eyes to
provide them with good unaided distance vision. The
eye can then accommodate to focus on intermediate
(eg. dashboard of car, computer) and near (eg.
reading) vision tasks.
Over the age of about 40 accommodation starts to
reduce and presbyopia sets in with the need to have to
wear reading glasses or bifocal or multifocal glasses.
The eye becomes increasingly “fixed” for best focus at
one particular distance.

22. Options for reducing spectacle dependence
Presbyopia creates a challenge in achieving independence
from glasses or contact lenses.
If both eyes are treated to provide good unaided reading
vision then good unaided distance vision is lost.
One option is “monovision” in which one eye is made slightly
short sighted to provide reading vision without glasses and
the other eye is made (or kept) as the eye with good unaided
distance vision.
Monovision can be performed with laser vision correction or
with cataract surgery.
Not suitable for everyone – often involves a contact lens trial
to assess suitability and likelihood of patient satisfaction.

23. Options for reducing spectacle dependence
For those over about 55 -60 years old one has to
consider the merits of lens-based surgery over corneal
laser vision correction as people in this age group may
begin to develop cataracts in the near future and lens-
based refractive surgery can not only reduce spectacle
dependence but get rid of a cataract if one is already
present and eliminate the need for a subsequent
cataract procedure in the future if the patient has no
cataract.

24. Cost Of Laser Vision Correction
The cost varies quite widely from about $1200 per eye to
about $3500 per eye.
Why the huge range in cost?
Quality of the technology available:
Bladeless LASIK involves two lasers – a femtosecond laser to cut the flap and
an excimer laser to reshape the cornea. Some centres use a motorised
mechanical blade (microkeratome) to cut the flap. Less precise than with
laser and higher rate of complications. A femtosecond laser costs about
$ 700,000 whilst a microkeratome costs about $40,000.The higher cost of the
femtosecond laser in bladeless LASIK is usually passed on to the patient.
The procedure being performed
Some centres only perform surface ablation. No corneal flap is made and no
femtosecond laser or microkeratome is required. Only the excimer laser is
needed and the savings can be passed on to the patient. However – increased
pain and longer healing time. More time required off work which may negate
the cost savings compared with LASIK.

25. Clinical case – Flap cut

26. Clinical case – flap cut

27. Clinical case – Flap
lift

28. Clinical case – Flap lift

29. Our results for 2013 with LASIK

30. 96.4%
3.6%
0% 20% 40% 60% 80% 100% 120%
N5 or
better
N6
Eyes
UnaidedDistanceVisualAcuity
Monovision–Unaided Near vision at 1month
Monovision Near Eye: Post-operatively 100% of the eyes that were made short sighted
achieved unaided near vision of N6 or better.

31. Thankyou

33. Page 33 VisuMax Product Introduction
VisuMax Femtosecond System
Clinical case – Flap lift