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Ultra-High-Resolution Optical Coherence Tomography Imaging in LASIK. Volkan Hurmeric MD Jianhua Wang PhD, MD Sonia H. Yoo MD ASCRS San Diego 2011 Financial Disclosure Sonia H. Yoo is a consultant for AMO/Intralase - PowerPoint PPT Presentation
Citation preview
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Purpose: is to investigate clinical applications of spectral domain ultra-high-resolution optical coherence tomography (UHR-OCT) imaging in femtosecond laser assisted LASIK (FS-LASIK) patients.
Anterior segment scanning Center wavelength: 840nm Bandwidth: 100nm Scan depth: 3mm Scan width: up to 15mm Scan speed: 24 frames per
second Axial resolution: ~3 µm
Advantage of UHR-OCT1.Noninvasive histological analysis: Image quality is similar to living biopsy2.Reliable thickness measurement
Methods: 28 patients who underwent FS-LASIK surgery were enrolled in the study.
Study group: 15 patients 9 patients (9 eyes) were scanned immediately after
femtosecond flap preparation 6 patients with opaque bubble layers (OBL), 2 patients with epithelial defects 1 patient with suction loss.
6 patients (9 eyes) were scanned at postoperative period 3 patients with epithelial ingrowth, 2 patients with epithelial breakthrough, 1 patient with post-LASIK haze
Control group: 13 patients, 22 eyes with uncomplicated FS-LASIK
were scanned at postoperative day 1 6 ♂, 7♀ Preoperative SE +3.00 / -8.00 dpt
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In 2 patients, OBL was located above the flap interface in UHR-OCT images. In these patients flap lift was unsuccessful due to incomplete lamellar dissection over the area of OBL
4Green arrows: flap interface, White arrows: Bowman layer
In 4 patients OBL was located under the flap interface. In these patients flaps were lifted without any complications
Our experience suggests that OBLs located above the flap interface may be a sign of an undissected flap zone and a
contraindication to flap lifting
Results Case 1
Case 5
• Post-LASIK examination revealed epithelial irregularities OS
• Epithelial irregularities were repositioned under the slit lamp with a forceps before UHR-OCT imaging
UHR-OCT images demonstrated residual epithelium penetrating into the side-cut (white arrow)
Epithelium
Flap
• Surgical Plan• Flap creation with 30 kHz FL
(without flap lift)• Implantable Collamer Lens
(ICL) implantation• Flap lift + Excimer laser
ablation (1 month after ICL)
• Preop refraction• OD -11.00 +2.00x85• OS -10.00 +1.25x90
• Pachymetry 498/507 μm
White line corresponds to the UHR-OCT image
Case 7
• 2 months post-LASIK exam revealed peripheral flap irregularity at the area with previous epi-defect (white arrow)
• Patient had no complaints & UCDVA was 20/15 OU
• UHR-OCT imaging demonstrated localized loss of flap tissue (asterix)
White line corresponds to the UHR-OCT image
*Epithelium
Flap
Residual epithelium at the side cut may be responsible for the
development of epithelial ingrowth and flap melt in FS-LASIK patients
Case 7
• 29 y/o ♂ patient operated with Intralase 30 kHz FL.
• Patient had suction loss during flap preparation
Red arrows: Flap irregularity due to suction loss
oUHR-OCT was performed before the flap was lifted
oUHR-OCT images confirmed that the structure and integrity of the flap was normal
oFlap lift and excimer laser was completed without any complication
Case 9
Case 11• 27 y/o ♀• Epithelial ingrowth after LASIK
enhancement
• UHR-OCT images demonstrate histological structure of the ingrowth in detail (white arrow)
• 25 y/o ♀underwent FS-LASIK for -8.25 / -9.00 D.
• Flap thickness was 110 μm (OD)
• Patient had bilateral corneal scars due to previous adenoviral infection
• Patient had epithelial breakthrough (red arrow) during FS flap preparation in the right eye
• UHR-OCT imaging was performed in the left eye. At some points corneal scars were found to be deeper than expected (white arrow).
• Flap thickness was adjusted to 130 microns and FS-LASIK was competed without any problem in the left eye
OD OS
Case 14*
* BCL
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UHR-OCT demonstrated focal breaks (white arrows) in Bowman layer and localized thickening of epithelial basement membrane. These areas were
corresponded to the areas where the haze was most severe.
o 4 month post-LASIK refraction was OD -2.25 +1.00x90, OS -1.0 D sphere
oBSCVA was 20/25 OUoSlit lamp showed interface haze with a
granular appearance.o Time domain OCT revealed flap
thickness of 73 μm & 81 μm OU.
• 42 y/o ♂ uncomplicated FS-LASIK for OD -9.00+1.00 X 95, OS -4.75+0.75X65 D
• Intended flap thickness was 110 μm
The association of corneal haze with areas of disruption of Bowman`s membrane has not been observed earlier. This
could potentially be a factor in determining the severity and extent of corneal haze in FS-LASIK
Case 15
Control group• 22 eyes with uncomplicated
FS-LASIK were scanned at postoperative day 1 with UHR-OCT
• All patients were operated with Intralase 30 kHz / Visx S4
• Flap thickness: 110 μm• Flap diameter: 9 mm• Raster energy: 1.9 μm
• In all patients flap structure was normal
• None of the patients had residual epithelium in the side cut.
• None of the patients had focal breaks at Bowman layer.
• None of the patients developed epithelial ingrowth or flap melt at postoperative 1 month
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Conclusions UHR-OCT helps us to document in-vivo morphology of the
cornea after refractive surgery similar to a living biopsy
UHR-OCT can be used to prevent flap related complications in FS-LASIK
UHR-OCT is gives us new information about the development of complications in refractive surgery
UHR-OCT will help us to better understand wound structure and wound healing after refractive surgery
Future studies are needed to confirm new clinical applications of high-resolution imaging in refractive surgery
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