LasekLasekwithwith

LADARVisionLADARVision 40004000

CSMUH OPH , MEI-LIN PENG

中山醫學大學附設醫院

眼科 彭美玲

LASEKLASEK

Laser Laser subepithelialsubepithelialkeratomileusiskeratomileusis

“With LASEK I have not had a dry eye problem with patients, as opposed to the several cases of neurotrophic keratitis I’ve seen with LASIK.”

--Robin Beran,MD

LASEKLASEK•Reduce postoperative pain and corneal

haze associated with PRK.

•Avoid flap-related complications associated with LASIK – free caps, incomplete pass of the microkeratome, flap wrinkles, epithelial ingrowth, flap melt, interface debris,and diffuse lamellar keratitis.

Patients selection in LASEKPatients selection in LASEK•Thin corneas

•Small optic zones with moderate thick cornea

•Small palpebral fissurs

•Dry eye, which would be aggravated by LASIK

•Large pupils

•An occupational or a recreational risk of trauma, which might disloge a LASIK flap

•Glaucoma

•Suspected keratoconus

•Very flat or very steep corneas

•Basement membrane dystrophies or loose epithelium

Alcon LADARVision 4000

Ex

Company Alcon Autonomous LaserSight Nidek Schwind Bausch & Lomb Visx

Laser LadarVision 4000 LaserScan LSX EC-5000 Esiris Technolas 217ZXyoptix Star S3

Spot Size (mm) 0.8 to 0.9 0.8 to 1 slit + 1 1 2, 1 variable spot, 0.65 to6.5

Spot Type Gaussian Gaussian Quasi-quassian Guassian Truncated gaussion 7-beam array

Rep Rate (Hz) 60 100/200 May-50 200 50 10.3Abl. Rate (s/D) 7 Approx. 9 Approx. 6 Approx. 8 4 Approx. 6Typ. Abl. Zone (mm) 6 6 to 7 5.5 to 6 6 to 7 6 to 7 6 to 6.5Abl. Range (mm) 4 to 8, 9 Hyp 3 to 9 5.5 to 10 1 to 10 to 15 6 to 8, 9 Hyp

Tracker Ladar tracker Video tracker NA Video tracker NA 3D active infra-redtracker

Sampling Rate (Hz) 4,000 60 60 300 120(200) 60Response Rate (Hz) 100 60 30 300 (?) 120 NADilation Yes No No No No NoCentration NA NA NA NA NA User-definedWavefront/Diagnostic LADARWave NA OPD-Scan NA ZyWave WaveScan

Type HS HS Topographer +retinoscopy TS (ORK-link) HS HS

Couple to laser Yes Not yetNo (floppy disc

via Final Fitsoftware)

Yes Yes Yes

Subjective or Objective Objective NA Objective Objective Objective Both

準分子雷射比較表

International LADARVision Use*

準分子雷射儀之發展1. 大光斑準分子雷射儀

美國在1986年開始臨床治療台灣在1992年由中山醫學大學首先引進作臨床治療

2. 小光斑飛點掃描準分子雷射儀美國在1999年開始臨床治療台灣在2001年由中山醫學大學再度領先引進

3. 波前鷹眼診斷儀配合小光斑飛點掃描準分子雷射儀美國在2001年5月開始臨床檢測中山醫學大學預計引進

Small Scanning Spot

•More precise corneal sculpting•Spot size: 0.8mm•Cornea flap hinge protection•Patented Pointillistic Algorithms

LADARVision Spot Ablation

LADARVision Spot Ablation

••ExcimerExcimer laser beamlaser beam:pulse energy: 2.4-3.0 mJBeam diameter:≤ 0.9 mmGaussian beam shapePulse frequency: 55-60 Hz

•8 sec/D - myopia

17 sec/D - hyperopia

大小光斑之比較

小光斑 2 mm

微光斑 0.8 mm

大光斑 1-7 mm

Flying Spot Broad Beam

Gaussian versus Flat-top profile

Characterization of “Eye Motion”

Typical standard deviation in eye position during surgery

Scanning Spot Delivery

Broad Beam vs. Scanning Spot

AblationPlume

CornealIrregulality

Yes No

追蹤 預測 及 反應

較低之追蹤頻率,較差之預測結果

較高之追蹤頻率,較好之預測結果

TrackerMirrors

TrackerSource

Excimer

Mirror adjustment time for a 1mm distance in the treatment plane

LADARVision 4000 Tracking system

Comparative Features of Eye tracking in scanning Excimer Laser

67 ms1 msResponse time

60,120,250, Hz4,000 HzDetection frequency

None905 mm diode laser

Transmittal signal

CCD/InfraredLaser RadarMethod

OthersLADARVisionLaser System

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