Refractive surgery for GP's

$Page 1: Refractive surgery for GP's$
Con Moshegov

FRANZCO, FRACS

Con MoshegovFRANZCO, FRACS

Refractive Eye Surgeon

Refractive Surgery What a GP should know

MOSHEGOV Perfect Vision






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


Cornea too steep


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



Radial Keratotomy

• No longer used

• Weakens cornea: danger in sports

• Glare and haloes at night

• Diurnal fluctuation in vision


Astigmatic Keratotomy (AK)

• Arcuate incisions in cornea

• ‘Relax’ the tight steep axis to relieve astigmatism

• Can be straight (transverse) – T cuts






PRK




• Does not occur if laser is applied directly onto stroma


LASIK


LASIK


Advantages of LASIK over PRK

• No risk of haze

• Much reduced degree of regression

• Almost no pain

• More accurate

• More rapid recovery of vision


Microkeratomes



LASIK using the Amadeus


Complications

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


Complications

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



LASIK induced ectasia


Contraindications

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





Complications

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


• 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)


Consent Video

• Video outlining

– process of procedure

– potential risks & complications


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


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


• Valium tablet - tranquiliser- muscle relaxant

• Anaesthetic drops• Reiterate details of what to expect

Preparation of the patient


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’


• 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


Follow up

• Next day

• 2 to 3 weeks

• 3 months

• 12 months

• Life time post operative support


Technolas 217z


VISX Star S4


Customised ablation

Wavefront technology


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

... to one point.

Ideal Optical System


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

... a plane wavefront.


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

... a deformed wavefront.


Wavefront: Basics

Incoming Wave

Lens System togenerate a

point at the retina

LASER

BEAM


CCD-Camera Lens Array

Outgoing Wave CCD-Image

Wavefront: Basics


Wavefront: Basics

CCD-Image

Example for a measured signal to reconstruct the wavefront!


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


Limitations of LASIK

• Extremes of refractive error

• Thin corneas

• <32D or >50D after treatment

• Irregular astigmatism

• Narrow orbit and deep set eyes


Alternative Options

• PRK

• Clear lens extraction

• Phakic IOL

• Combinations of the above


CLE

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


CLE

Concerns:

• Risks of intraocular surgery

retinal detachment

endophthalmitis• Eliminates accomodation


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


CLE

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


Surgery

• phacoemulsification

• topical anaesthetic

• small incision (no sutures)


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


CLE

Residual refractive error• Bioptics

– LASIK– 3 months post op


Array Multifocal IOL

Silicone 3 piece lens


The ARRAY®IOLRefractive Multifocal IOL Design

• Five concentric zones

• Each zone has a near, intermediate and distance

weighting

• Odds = weighted distance

• Evens = weighted near


Accommodating IOL


Myth

• My cataract was removed with a laser


Myth

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


Myth

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

• Monovision

• (non laser methods)


Myth

• Laser eye surgery will fix my eyesight forever


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


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


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.

Health & Medicine

Refractive surgery for GP's