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REFRACTIVE SURGERIES
CLASSIFICATION
REFRACTIVE SURGERIES
CORNEA BASED
-RK
-PRK
-LASIK
-EPILASIK
-LASEK
-Corneal
Inlays and
rings
LENTICULAR BASED
-Clear Lens
extraction for
myopia
-Phakic IOL
- Prelex Clear
Lens Extraction
with use of
Multifocal IOL’s
COMBINED(BIOPTICS)
Combination
of the two
LASIK(Laser Assisted In Situ
Keratomileusis)
 Procedure using laser to ablate the tissue
from the corneal stroma to change the
refractive power of the cornea
 Types of lasers used Excimer-Excited dimer of two atoms
-an inert gas(Argon)
-Halide(Fluoride)
which releases ultraviolet energy at193nm for
corneal ablation
Patient selection
 Patients need to be fully informed about
potential risks,benefits and realistic expectations
 Age > 18 years
 Refractive status stable > 1 year.
 Current FDA approval Myopia-upto -12D
 Hyperopia –upto +6D
 Astigmatism-upto 7D
 CCT such that minimum safe bed thickness
left(250-270µ).
 Post op Corneal thickness should not be
<410µ.
 Cornea not too flat or steep.<36D or
>49D(Poor Optics).
CONTRAINDICATIONS
 Systemic factors
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




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Poorly controlled IDDM
Pregnancy/lactation
Autoimmune / connective tissue disorders(RA,SLE,PAN etc)
Clinically significant Atopy,Immunosuppressed patients
Keloid tendency(esp PPK)
Slow wound healing-Marfans,Ehler-Danlos
Systemic Infection-(HIV,TB)
Drugs-Azathioprene,Steroids(Slow wound healing)
CONTRAINDICATIONS
 Ocular Factors Glaucoma,RP(Suction Pressure-ON damage,Blebs)
 Previous h/o RD or f/h of RD.
 One eyed individual
 Pre-existing dry eye,Keratoconus.pellucid marginal
degeneration,Superficial corneal
dystrophy,RCE,Uveitis,early Lenticular changes
 h/o Herpetic Keratitis(one year prior to surgery)
PREOPERATIVE EVALUATION PRIOR
TO LASIK
 Record UCVA and BCVA
 Dry and wet manifest
 Pupillometry-Infrared Pupillometer
-Aberrometer
 Large pupil-Increased HOA perceived so
increased glare
-Can change Optic Zone
 Slit Lamp Examination Rule out blepharitis, miebomianitis, pingecula,
Pterygium,corneal neovascularization
 Other contraindications for LASIK.
 IOP by applanation
 Dilated Fundus Examination to role out holes
,tears.
 Tear film asessment-Schirmers,TBUT and
Lissamine staining
 Blink Rate-(Normal---3-7/min)
 Corneal Topography Schiempfug /Scanning slit/placido disc
 Stop RGP lenses 2 weeks prior and soft lenses I wk
prior
 To rule out early Keratoconus and other ectasias
 For mean K values
 Pachymetry -For CCT (Ultrasound/Optical)
 Contrast Sensitivity testing for pre-operative
baseline.
BASIC STEPS AND MACHINE
SPECIFICATIONS
 Topical anasthesia-Proparacaine 0.5%,
Lignocaine 4%.
 Surgical Painting and draping(Lint Free).
 Lid speculum with aspiration.
 Corneal marking-Orientation of free cap
Creation of flap 1st Step-Creation of suction by suction pump
to raise the IOP to 65 mm Hg which is
necessary for the microkeratome to create a
pass and resect the corneal flap.
 This is crosschecked with Barraquers
tonometer.
 2nd step-Resection of corneal flap
Microkeratome
Femtosecond Laser
(Intralase)
 Microkeratome Uses Disposable blades
 Blade Plate can be set at 90µ,120µ,140µ,160µ
and180µ.
 Nasal or superior hinge flaps can be created.
 Eg.Hansatome,XP Microkeratome, ACS, Carriazo
Barraquer, Moria,Amadeus
 Femtosecond Laser for Flap Creates photodisruption using femtosecond solid




state laser with wavelength of 1053nm.
Needs lower vacum.
Very short pulse with spot size of 3µ-High precision
cutting device.
Any hinge can be made
Can make flaps as thin as 100µ(Sub Bowmanns
Keratomileusis)
 Flap has vertical edges –so reduced epithelial
ingrowth.
 Microkeratome flap thicker in periphery and
thinner in the centre.Not so with Intralase(Planar).
 3rd Step-Delivery of Laser After flap is lifted, laser is applied to the
stroma according to the ablation profile
calculated by the machine.
 Laser beam is delivered by the following ways
depending on the machineBeam Delivery
Broad Beam
Scanning Slit Beam
Flying Spot
 Most machines employ a flying spot to
deliver laser with the help of incorporated eye
tracker.
 4th step-Reposition Of the Flap After irrigating interface ,flap reposited
 Adhesion test-Striae test
COMPLICATIONS OF LASIK
 Under/over correction and regression (over
time).
 Post –op Keratectasia




Presents 1-12 months
Progressive regression
Treatment-RGP,Corneal transplant.
Prevention-Leave residual stromal bed>280
-Do surface ablation
-Don’t violate corneal topography diagnosis
of forme-fruste keratoconus
COMPLICATIONS OF LASIK
 Night vision disturbances-Haloes/Glare
 Decenteration and central islands.
 Post Lasik Dry eye Fluctuating vision,SPK
 Temporary neuropathic cornea
 Confocal microscopy-90% reduction in corneal nerve
fibres-regeneration by 1 year.
 Rx-Preservative Free lubricants
COMPLICATIONS OF LASIK
 Post op Glaucoma(Pseudo DLK)-Steroid
induced.
 Vitreoretinal Complications Increased risk of RD due to alteration of anterior
vitreous by suction ring-Risk 0.08%.
 PVD(0.1% Risk)
 Macular Hemorrage(0.1% Risk)
COMPLICATIONS OF LASIK
 Flap Complications Button Hole-If
K>50D,due to central
corneal buckling.
 Irregular thin flap-
Inadequate suction/old
blade
 Short Flap-Hinge
encroaches on visual
axis-Due to jamming of
microkeratome with
hair/FB
SHORT FLAP
 Free Cap-Due to flat
pre –op K(<38D).
 .Flap undulations Macrostriae-Linear lines in
clusters,seen on
retroillumination.
Causes-Incorrect position of
flap
-Movement of flap
after LASIK
Rx-Lift flap
-Rehydrate and float it back
-Check for flap adhesion
MACROSTRIAE
 Microstriae-Flap in
position but fine
wrinkles seen
superficially
-Due to large
myopic ablation
-Rx- Observe.They
resolve spontaneously
MICROSTRIAE
 Bleeding during flap cutting due to corneal
neovascularization in contact lens users
 Interface Inflammation(Sands Of
sahara/DLK)-Non-Infective inflammation at
the interface seen in 1st week after LASIK.
 Diffuse,confluent,white granular material at the
interface 1-7 days after LASIK.
 Slight CCC
 No AC reaction
 Reduced Visual acuity
 Grade 1-
Focal involvement Normal V/A.
Rx Intensive topical
steroids.
 II – Diffuse
involvement –Normal
V/A.
Rx-Add systemic
steroids.
 III – Diffuse confluent
granular depositsReduced V/A.No AC
reaction.
Rx-Same as
above+Antibiotics
 IV - Diffuse confluent
granular deposits +intense
central striae.
Marked Reduced V/A
Rx-Interface irrigation +
above
 Epithelial ingrowth-Presents 1-3 months after
LASIK.
 Causes-Epithelial cells trapped under flap
 Risk factors-Peripheral epithelial defects
-Poor flap adhesion
-Buttonholed flaps
-Repeat LASIK
 Classification GRADE 1-Faint white line <2mm from flap edge
 GRADE 2-Opaque cells <2mm from flap edge with
rolled flap edge
 GRADE 3-Grey to white fine opaque line extending
>2mm from flap edge.
 GRADE 4-If ingrowth >2mm from edge with
documented progression—Lift flap and remove the
sheets of epithelium.Can use MMC.
EPILASIK / LASEK
 Anterior stroma of cornea (ant. 1/3 rd)
has stronger interlamellar connections than
post. 2/3rd.
So surface ablation preserves the structural
integrity better than LASIK especially in the
correction of moderate to high myopia.
 LASEK-Camellins Technique 20% absolute alcohol used for 20-35s. To raise
epithelial flap.
 Flap reposited after ablation
 EPILASIK- Epithelial keratome used to lift
epithelial flap of about 60-80µ thick.
 Epithelial keratomes use
- PMMA blades
-Metal Epithelial Separator
CORNEAL INLAYS
 Increase the depth of focus by using pinhole
optics.
 Inlays have 1.6mm centre with 3.6mm surround.
 Near vision improves by 1.5D with no loss of
distant vision.
 Used in the non –dominant eye.
 These are hydrogel based.Placed in a tunnel 200400 µ deep in centre of cornea.
AcuSof Corneal inlay
Phakic IOLs


An intra-ocular lens is placed inside the eye in
front of the patient’s natural lens.
These are available in three types
1.
2.
3.
Anterior chamber angle fixated IOL – Nuvita
(Bausch & Lomb), Kelman duet, I care (corneal),
Vivarte (Ciba vision)
Iris supported phakic IOL – Verisyse/ Artisan
(AMO/Ophtec)
Plate lens that fits between the iris & the crystalline
lens – Starr implantable contact lens (ICL), PRL
(Ciba).
Indications
 Age above 18 years
 Stable refraction for one year
 Patients not suitable for LASIK/LASEK due to
high powers or thin corneas
 AC depth 3.0 mm
 Endothelial count >2000cells/cumm
 No other ocular pathology
Contraindications
 Myopia other than axial myopia
 Corneal dystrophy/ Endothelial cell count
<2000cells/cumm
 Anterior chamber depth less than 3.0mm
 History of uveitis
 Presence of anterior/posterior synechiae
 Glaucoma or IOP higher than 20 mmHg
 Evidence of nuclear sclerosis or developing cataract
 Personal or family history of retinal detachment
 Diabetes mellitus
Verisyse Phakic IOL
Pre-op assesment for phakic IOL
 Refraction – Objective & subjective acceptance
at 12mm vertex distance
 Anterior chamber depth – from epiuthelium to
endothelium
 Anterior & posterior segment examinations
 K-reading & Topography – Orbscan-II
 Intra-ocular pressure
 White to white measurement
 Specular microscopy
Veriflex (artiflex)
 Foldable iris claw lens. It is a modification of
Verisyse (Artisan) phakic IOl.
Posterior chamber lenses

These phakic IOLs are placed in the
posterior chamber between the iris & the
crystalline lens. These are
Starr ICL
2. Cibavision PRL
3. IPCL
1.
STAAR ICL
 The STAAR Collamer ICL and the TORIC ICL are
posterior chamber phakic intraocular lenses.
Made of Collamer, STAAR’s proprietary collagen
copolymer (collagen/HEMA), the lens rests
behind the iris in the ciliary sulcus.
Complications
 ICL decentration
 Pupillary block
 Pigment dispersion
 Subcapsular cataract
Advantages of phakic IOLs over
laser corrective procedures
 A higher range of refractive errors can be corrected
 Reversible: Phakic IOL implantation is a potentially
reversible procedure
 Safe: No structural changes are induced. Hence it is safe
in any eye with high error & also thin corneas.
 Better quality of vision: Quality of vision (contrast
sensitivity) is better than the laser refractive procedures
in eyes with higher refractive errors and no induced
higher order aberrations. There is also a considerable
improvement in BVCA with these lenses because of the
magnification effect.
 Highly skilled procedure: Prevents misuse of the
procedure.
Bioptics

Bioptics is a combination of phakic IOL and LASIK.
Bioptics is done for the correction of the residual
spherocylindrical power when a spherical implant
is used.