Refractive surgery for GP's

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Perfect Vision's Dr Con Moshegov presentation on: Refractive surgery for GP's

Transcript of Refractive surgery for GP's

Con Moshegov

FRANZCO, FRACS

Con MoshegovFRANZCO, FRACS

Refractive Eye Surgeon

Refractive Surgery What a GP should know

MOSHEGOV Perfect Vision

MOSHEGOV Perfect Vision

MOSHEGOV Perfect Vision

MOSHEGOV Perfect Vision

MOSHEGOV Perfect Vision

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Refractive Error

• Myopia: can’t see in the distance

• Hypermetropia: can’t see at near

• Astigmatism: blurred at any focal length

• Presbyopia: need for longer arms to read

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Cornea too steep

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Correction of Refractive Error

• Glasses• Contact Lenses• Surgery:

– Incisional (RK, AK, ‘T cuts’)– Cataract Surgery– Implantation of phakic (contact) lens– Excimer Laser PRK – LASIK– VISX Wavefront guided customised treatment

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Radial Keratotomy

• No longer used

• Weakens cornea: danger in sports

• Glare and haloes at night

• Diurnal fluctuation in vision

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Astigmatic Keratotomy (AK)

• Arcuate incisions in cornea

• ‘Relax’ the tight steep axis to relieve astigmatism

• Can be straight (transverse) – T cuts

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PRK

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• Does not occur if laser is applied directly onto stroma

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LASIK

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LASIK

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Advantages of LASIK over PRK

• No risk of haze

• Much reduced degree of regression

• Almost no pain

• More accurate

• More rapid recovery of vision

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Microkeratomes

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LASIK using the Amadeus

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Complications

• With creation of flap:– Incomplete– Free– Damaged– Epithelial defect

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Complications

• With laser ablation of bed:– under or over correction– regression can still occur– decentration– glare, haloes, starbursts, especially at night– excessive thinning

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LASIK induced ectasia

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Contraindications

• Absolute: Keratoconus– Ectasia– Thinning and forward protrusion– Results in myopia and astigmatism– Associated with atopy

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Complications

• With interface– Implantation of foreign matter or epithelial cells– Inflammation under the flap– Infection (extremely rare)

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• Most common causes for dissatisfaction:– Not surgical complications, rather….

1. Dry eyes

2. Lack of independence from reading glasses

Day of Consultation(pre-operative evaluation)

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Consent Video

• Video outlining

– process of procedure

– potential risks & complications

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Pre-operative Evaluation• Answering of any questions arising from video• Medical and eye history• Atlas topography• Orbscan• Check previous or current glasses• Autorefraction• Manual refraction

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Doctors Assessment• Review corneal maps• Refraction• Confirm suitability • Comprehensive eye exam• Informed consent

– risks & complications– specific statistics related to individual

• Given time to consider

The Day of Treatment

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• Valium tablet - tranquiliser- muscle relaxant

• Anaesthetic drops• Reiterate details of what to expect

Preparation of the patient

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1. Lid speculum: blinking not a problem2. Pressure and loss of vision with suction3. Sound of motor of microkeratome4. Odour during lasering5. Movement won’t blind: 3D tracker

‘you can expect’

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• antibiotic and anti-inflammatory drops for 7 days

• lubricating drops as necessary• shield at night for 2 nights• avoid swimming and eye make up for 2

weeks

Post operative regime

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Follow up

• Next day

• 2 to 3 weeks

• 3 months

• 12 months

• Life time post operative support

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Technolas 217z

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VISX Star S4

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Customised ablation

Wavefront technology

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Wavefront: Basicsfocuses incoming rays with a plane wavefront ...

... to one point.

Ideal Optical System

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Wavefront: BasicsOutgoing light rays from a focal point have again ...

... a plane wavefront.

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Wavefront: BasicsOutgoing light rays from a system with Aberrations have ...

... a deformed wavefront.

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Wavefront: Basics

Incoming Wave

Lens System togenerate a

point at the retina

LASER

BEAM

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CCD-Camera Lens Array

Outgoing Wave CCD-Image

Wavefront: Basics

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Wavefront: Basics

CCD-Image

Example for a measured signal to reconstruct the wavefront!

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Integration of WaveScan® WaveFront System with the VISX STAR ActiveTrak™

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Limitations of LASIK

• Extremes of refractive error

• Thin corneas

• <32D or >50D after treatment

• Irregular astigmatism

• Narrow orbit and deep set eyes

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Alternative Options

• PRK

• Clear lens extraction

• Phakic IOL

• Combinations of the above

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CLE

Definition• Removal of non cataractous crystalline lens• Implantation of IOL• Purely for refractive purposes• Not chargeable to Medicare

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CLE

Concerns:

• Risks of intraocular surgery

retinal detachment

endophthalmitis• Eliminates accomodation

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CLE

• Retinal Detachment after Clear Lens Extraction for High Myopia Seven year follow up

Colin J, Robinet A, Cochener B.

Ophthalmology 1999; 106:2281-2285

52 eyes with myopia > -12.0D

RD in 2% at 4years and 8% at 7 years

nearly double estimated for similar unoperated eyes

despite prophylactic laser

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CLE

Typical patient:• Over 40 years• Hyperopic• Desperately wanting freedom from glasses

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Surgery

• phacoemulsification

• topical anaesthetic

• small incision (no sutures)

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Limbal relaxing incisions• deep incisions in peripheral cornea• guarded diamond blade• 500 to 600 micrometers deep

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CLE

Residual refractive error• Bioptics

– LASIK– 3 months post op

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Array Multifocal IOL

Silicone 3 piece lens

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The ARRAY®IOLRefractive Multifocal IOL Design

• Five concentric zones

• Each zone has a near, intermediate and distance

weighting

• Odds = weighted distance

• Evens = weighted near

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Accommodating IOL

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Myth

• My cataract was removed with a laser

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Myth

• They had to take my eye out to remove the cataract and then they put it back again

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Myth

• The advertisement said they can make me do away without the need for reading glasses

• Monovision

• (non laser methods)

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Myth

• Laser eye surgery will fix my eyesight forever

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Take home points

• LASIK is the most popular form of refractive surgery

• Complications can occur but are rarely devastating

• New developments include customised or wavefront treatments and sophisticated 3D trackers

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Take home points• Cataract surgery is an alternative refractive

procedure but is less accurate• Cataract extraction is now possible under

topical anaesthetic • The cataract is removed using mechanical

fragmentation at ultrasonic frequencies not laser

• New developments include multifocal and accomodating implants

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Conclusion

• Refractive surgery, both laser and lens procedures, is said to be the most rapidly evolving subspecialty not only of ophthalmology but medicine!

• So ongoing education is essential.• I hope this presentation will help

General Practitioners have a better appreciation of it’s scope.