Non Incisional, Non Laser Refractive Surgery

Dr. Ankit Gupta

2 CATEGORIESA CORNEAL Epikeratophakia Intracorneal rings

B LENTICULAR Clear lens extraction Phakic IOLs

NON INCISIONAL NON LASER REFRACTIVE SURGERY

KERATOPHAKIA In keratophakia, a plus-powered lens is

placed intrastromally to increase the curvature of the anterior cornea to correct hyperopia and presbyopia.

A central lamellar keratectomy is performed with a microkeratome or femtosecond laser, the flap is lifted, the lenticule is placed onto the host bed, and the flap is replaced and adheres without sutures.

KERATOPHAKIA

Kaufmann , werblin in 1980 To eliminate the complexity of the lamellar

dissection Epikeratoplasty involved suturing a preformed

homoplastic lenticule directly onto the Bowman layer of the host cornea.

Graft rejection did not occur because no viable cells existed in the donor tissue.

EPIKERATOPHAKIA

SCHEMATIC PRESENTATION

EPIKERATOPHAKIA

INDICATIONS1. Aphakia2. Myopia3. Hyperopia4. Keratoconus

COMPLICATIONS1. Poor adherence of

the graft2. Infection3. Epithelial ingrowth

into the bed4. Poor predictiblity

of the results5. Corneal edema

EPIKERATOPHAKIA

Are implanted into the peripheral cornea , producing a vaulting effect that flattens the central cornea and corrects upto the 3D of myopia.

INTRASTROMAL RING SEGMENTS

HOW INTACS WORK

Made up of PMMA Outter diameter 8.1mm Inner diameter 6.7mm Arc length 150 ° Positioning hole diameter 0.28mm Ring cross sectional – hexagonal Each package consists of two rings Available in 11 thickness from 0.210mm to

0.450mm

FEATURES OF ICRS

REFRACTIVE EFFECT OF INTACS IS DIRECTLY RELATED TO ITS THICKNESS

Myopia upto -3D Keratoconus Pellucid marginal degeneration Post LASIK corneal ectasias.

INDICATIONS OF ICRS

Patient should have central clear cornea. Thickness of cornea should be greater than

450micron at the incision site.

PREREQUISITES FOR ICRS

Collagen vascular disease Autoimmune, or immunodeficiency diseases Pregnant or breastfeeding women Presence of ocular conditions such as

recurrent corneal erosion syndrome Corneal dystrophy that may predispose the

patient to future complications.

CONTRAINDICATIONS OF ICRS

The procedure involves creating a lamellar channel at approximately 68%-70% stromal depth, followed by insertion of the ring segments.

Pachymeter is used to measure the thickness of the cornea over the entry mark

TECHNIQUE FOR ICRS

The geometric center of the cornea is marked with a blunt hook.

A diamond knife is set to 68%-70% of the stromal depth and then used to create a 1.0-mm radial incision.( also by femtosecond laser)

Corneal tunnels are then created at approximately 2/3rd of stromal depth using pocketing hook.

Intacs are then implanted. Tissue glue or 10-0 nylon sutures may be used

to close the radial incision at the corneal incision.

TECHNIQUE FOR ICRS

INTACS INSERTION

Removal or exchange rate – 3 % to 15 % Most common reason for exchange is

residual myopia. Removal of ring is done usually because of

disabling vision symptoms such as glare , double vision and photophobia.

REMOVAL OR EXCHANGE OF ICRS

Adverse events (defined as events that, if left untreated, could be serious or result in permanent sequelae) occur in approximately 1% of patients.

1. Anterior chamber perforation2. Microbial keratitis3. Implant extrusion4. Shallow ring segment placement5. Corneal thinning over Intacs

ADVERSE EVENTS OF ICRS

EXTRUSION

TIP EXTRUISON

CORNEAL THINNIG OVER INTACS

Ocular complications defined as clinically significant events that do not result in permanent sequelae occurs in approximately 11% of patients.

1. Reduced corneal sensitivity.2. Induced astigmatism between 1.00 and

2.00 D.3. Deep neovascularization at the incision site.4. Persistent epithelial defect.5. Iritis/uveitis.

COMPLICATIONS OF ICRS

DEFINITION Artificial lenses implanted in the anterior or

posterior chamber of the eye in the presence of the natural crystalline lens to correct refractive errors.

PHAKIC IOLs

1950s - correcting myopia by inserting a

concave lens into the phakic eye 1988 - Baikoff : anterior chamber angle-fixed

PIOL Mid 1980s - Posterior chamber phakic IOLs :

Fyodorov 1991 - Artisan-Worst iris claw lens

HISTORY OF PHAKIC IOLs

Can treat a larger range of refractive errors Allows the crystalline lens to retain its

function preserving accommodation (as compared with refractive lens exchange)

Removable and exchangeable. Less expansive Lower risk of endophthalmitis and post op

retinal detachment because the barrier of crystalline lens is present.

ADVANTAGES OF PHAKIC IOLs

Potential risks of an intraocular procedure   Nonfoldable models require large incision that

may result in high postoperative astigmatism.

PC PHAKIC IOLs have a higher incidence of cataract formation.

At the time of cataract surgery posterior PHAKIC IOL has to be removed possibly through a larger than usual wound.

AC PHAKIC IOLs may damage corneal endothelium.

DISADVANTAGES OF PHAKIC IOLs

Anterior chamber –angle supported PIOL AC iris fixated Posterior chamber PIOL

TYPES OF PHAKIC IOLs

MODEL AVAILABLE POWER

OPTIC SIZE/EFFECTIVE DIAMETER

(mm)

MATERIAL

Acrysof -8.00 to -16.00D

5.5 Acrylic

Phakic 6 H2 -4.00 to -20.00+2.00 to +10.00

5.5-6.0 PMMA

KELMAN DUET -6.00 to -20.00 6.3 Silicon opticsPMMA haptics

ANGLE SUPPORTED PIOLs

Rigid PMMA angle-supported Phakic 6 lens

KELMAN DUET LENS

(A). The haptics are implanted initially through a small incision (B), then the optic is injected (C). The complex optic-haptics is assembled inside the anterior chamber

MODEL AVAILABLE POWER

OPTIC SIZE/EFFECTIVE DIAMETER

(mm)

MATERIAL

VERISEYE MODEL

-5.00 to -20.00 5.0 PMMA

Artiflex/ Veriflex -3.00 to -23.50 8.5 Polysiloxane

IRIS SUPPORTED PIOLs

Foldable iris-fixated Artiflex lens

MODEL EFFECTIVE POWER

OPTIC SIZE/EFFECTIVE DIAMETER

(mm)

MATERIAL

VISIAN ICL -3.00 to -20.00 4.9-5.8 Collamer

POSTERIOR CHAMBER PIOLs

Age above 21 years Stable refraction for more than one year AC depth >= 3.2mm for iris-claw lens >= 2.5mm for pc PIOLs Minimum endothelial cell density > 3500 cells/mm² at 21 yrs age > 2800 cells/mm² at 31 yrs age > 2200 cells/mm² at 41 yrs age > 2000 cells/mm² at 45 yrs age No other ocular pathology (corneal disorders,

glaucoma, uveitis, cataract)

PREREQUISITES FOR IMPLANTING PIOLs

A) FOR HIGH MYOPIA-8.00 D to -20.00 D FDA APPROVED1. Artisan (iris supported) Myopia -5.00 to -20.00 D Astigmatic correction of 2.5D Age ›21 yrs ACD ›3.2mm

INDICATIONS OF PIOLs

A) FOR HIGH MYOPIA-8.00 D to -20.00 D FDA APPROVED2) ICL (POSTERIOR CHAMBER PIOL) Myopia -3.00 to -20.00D Astigmatic correction of 2.5D Age 21 yrs to 45yrs ACD ›3mm

INDICATIONS OF PIOLs

B) FOR HYPERMETROPIAAvailable power in

1. ICL upto +20.00 D2. ARTISAN upto +12 D

INDICATIONS OF PIOLs

C) FOR ASTIGMATISM PIOLs are available upto 6D But treatment of choice is laser ablation

upto 4 to 5 D

INDICATIONS OF PIOLs

Preexisting ocular diseases – 1. Compromised corneal endothelium2. Iritis3. Rubeosis iridis4. Cataract5. Glaucoma AC depth AC diameter Pupil size

CONTRAINDICATIONS OF PIOLs

Must be appropriate

The critical parameter in sizing the ICL isthe white-to-white (WW) measurementwhich can be measured with a Pentacam,OrbScan, UBM or using calipers.When implanting a angle supported PIOL – 2 peripheral iridotomies are done between 10’O clock to 2’O clock position 2 to 7 days prior to the surgery.

IMPORTANTS SURGICAL POINT

Vault is the space between the posterior surface of PIOL and the anterior lens capsule.

Shallow vault - will cause ICL contact with the crystalline lens and increases the risk of cataract formation over time.

High vault will rub against the iris and will cause the chronic iritis and pigment dispersion glaucoma

IMPORTANCE OF VAULT

VAULTSMALL Less than 0.25mmEXCESSIVE More than 0.75mmIDEAL 0.5mm

ICL IMPLANTATION

ICL REMOVAL

Changes in vaulting with accommodation. Loss of Corneal Endothelial Cells. Pupil Ovalization / Iris Retraction. Glare,Halos. Pigment dispersion glaucoma. Chronic Inflammation or Uveitis. Pupillary Block Glaucoma. Phakic Intraocular Lens Rotation. Cataractogenesis. Retinal Detachment.

COMPLICATIONS OF PIOLs

The combination of phakic IOL implantation followed by LASIK in patients with extreme myopia or hypermetropia and high levels of astigmatism.

When an anterior chamber phakic IOL is planned to be combined with LASIK, the corneal flap can be created just prior to the insertion of the lens; then, at a later time, usually after 1month, the flap is lifted for laser correction of the residual ametropia. This two-step technique was called adjustable refractive surgery (ARS) by Guell.

The rationale in performing the flap first is to avoid any possibility of contact between the endothelium and the IOL during the suction and cut for the LASIK procedure.

BIOPTICS