High-resolution Fourier-domain Optical Coherence Research Articles

THE DOSE-DEPENDENT MACULAR THICKNESS CHANGES ASSESSED BY FD-OCT IN PATIENTS WITH RETINITIS PIGMENTOSA TREATED WITH CILIARY NEUROTROPHIC FACTOR

To evaluate the effect of intravitreal ciliary neurotrophic factor (CNTF) implant on mean macular thickness (MMT) in eyes with retinitis pigmentosa using high-resolution Fourier domain optical coherence tomography imaging. A cohort of 8 patients (CNTF-3: n = 5; CNTF-4: n = 3) enrolled in Neurotech sponsored Phase 2 clinical trial underwent Fourier domain optical coherence tomography imaging. A ≥3% change in MMT from baseline or fellow eye was considered as a measurable change. Two patients enrolled in the CNTF-3 study received low-dose implant. At 18 months, a change in MMT from -4.47 μm to 6 μm from baseline was noted. Six patients received high-dose implant (CNTF-3: n = 3; CNTF-4: n = 3). In CNTF-3 group, 1 eye showed an increase in MMT by 19.25 μm (+7.6%) from baseline at 18 months. In CNTF-4 group, 1 eye had an increase in MMT of 27.08 μm (+11%) from baseline at 30 months; second eye had increase in MMT of 31.36 μm (+12%) from contralateral eye. Amongst these 3 responsive high-dose implant eyes, overall thickening of the retina could not be attributed to any specific retinal layer. A heterogeneous dose-dependent response on MMT was noted in eyes treated using intravitreal CNTF implant for retinitis pigmentosa. We recommend corroboration of our findings with Neurotech sponsored clinical trial results.

VISUAL OUTCOME CORRELATES WITH INNER MACULAR VOLUME IN EYES WITH SURGICALLY CLOSED MACULAR HOLE

To determine the macular morphologic features that correlate best with visual outcome in eyes with surgically closed idiopathic macular hole. Transversal observational case series of 24 eyes (22 subjects) imaged postoperatively using high-resolution Fourier domain optical coherence tomography (FD-OCT). Total and inner macular volume for central 3 mm area, central foveal thickness, and size of foveal inner segment-outer segment junction abnormality were correlated with best-corrected visual acuity. Microperimetry (MP-1) test was performed in a subset of 18 eyes. Mean postoperative best-corrected visual acuity was 20/36 (range, 20/25-20/70). Postoperative follow-up mean was 32.97 ± 24.68 months (range, 5-96 months). Eighteen eyes underwent internal limiting membrane (ILM) peeling. Among FD-OCT parameters, logarithm of the minimum angle of resolution best-corrected visual acuity and mean total microperimetry-1 sensitivity correlated best with inner macular volume in all eyes and ILM-peeled eyes (P < 0.05). Macular surface irregularities were noted in 12 eyes (66.7%) with ILM peeling but in none of the non-ILM-peeled eyes (P = 0.02). No significant correlation was found between microperimetry-1 sensitivity and other FD-OCT parameters. Because inner macular volume strongly correlated with visual outcome in eyes with surgically closed macular hole, the possible effect of ILM peeling on visual outcome needs to be further investigated.

TEN-YEAR FOLLOW-UP OF EYES TREATED WITH STEREOTACTIC FRACTIONATED EXTERNAL BEAM RADIATION FOR NEOVASCULAR AGE-RELATED MACULAR DEGENERATION

To determine the long-term effects of stereotactic fractionated external beam radiation on eyes treated for neovascular age-related macular degeneration. A retrospective review of all eyes treated with stereotactic fractionated external beam radiation (20-40 Gy, 2-Gy fractions) between 1997 and 2000 was performed to identify eyes with ≥ 2-year follow-up for analysis. A subset was imaged prospectively using a high-resolution Fourier-domain optical coherence tomography. Among 94 eyes treated, 33 eyes (32 subjects) had ≥ 2-year follow-up information (mean follow-up, 6.2 years; range, 2-10 years). Final visual acuity ranged from 20/50 to no light perception. Final macular findings included central geographic atrophy (49%), disciform scar (30%), and active choroidal neovascular membrane (9%). Fourier-domain optical coherence tomography images of three eyes with geographic atrophy revealed photoreceptor layer loss within areas of geographic atrophy with intact retinal morphology in areas of radiation exposure outside geographic atrophy. Radiation retinopathy was suspected in 18% and confirmed by fluorescein angiography in 15%, ranging from mild to neovascular glaucoma/phthisis bulbi (2 eyes). Mean time from stereotactic fractionated external beam radiation to development of radiation retinopathy was 5.4 years (range, 1-10 years). A moderate rate of delayed radiation retinopathy was noted in eyes with neovascular age-related macular degeneration treated with stereotactic fractionated external beam radiation. Geographic atrophy was a common finding.

Macular changes detected by Fourier‐domain optical coherence tomography in patients with hypotony without clinical maculopathy

To investigate macular changes in eyes with postoperative hypotony without clinical maculopathy using high-resolution Fourier-domain optical coherence tomography (FD-OCT). Fourteen eyes of 12 patients with postoperative intraocular pressure (IOP) ￡ 6 mmHg for at least 4 weeks but with no detectable clinical features associated with hypotony maculopathy were imaged by FD-OCT prospectively. Images were analysed by two retina specialists masked to clinical findings. Most patients were female (83%) and myopic (75%) with a mean age of 65 ± 17 [standard deviation (SD)] years (range 2–86 years). Mean central corneal thickness was 519 ± 34 lm [95% confidence interval (CI) 502–537] and mean IOP before surgery was 20 ± 8 mmHg (95% CI 15–24). During the period of hypotony (mean 15 ± 6 weeks), the average mean IOP was 4 ± 1 mmHg (95% CI 3–5). Abnormal FD-OCT findings (retinal folds and ⁄ or intraretinal fluid) were present in eight eyes. These patients had a higher rate of visual symptoms (75% versus 17%), visual acuity loss (‡ 2 lines; 63% versus 17%) and increased mean foveal thickness (250 ± 26 versus 210 ± 12 lm; p < 0.01, Mann–Whitney U-test) compared with those with normal FD-OCT. FD-OCT identified subclinical macular abnormalities in over half of the eyes with postoperative hypotony. These findings were accompanied by visual disturbances and central macular thickening. FD-OCT can be an important diagnostic tool for this disorder when clinical features are absent.

High-Resolution Fourier-Domain Optical Coherence Tomography Findings in Vitelliform Detachment Associated with Basal Laminar Drusen

Pilli, Suman MD; Zawadzki, Robert J PhD; Werner, John S PhD; Park, Susanna S MD, PhDEditor(s): Toth with Shelley Day, Cynthia A; Ehlers, Justis P Author Information

Fourier-domain optical coherence tomography of eyes with idiopathic epiretinal membrane: correlation between macular morphology and visual function

The purpose of this study is to evaluate the macular morphological changes associated with idiopathic epiretinal membrane (iERM) using high-resolution Fourier-domain optical coherence tomography (FD-OCT), as they correlate with visual acuity and microperimetry (MP-1). In all, 24 eyes (19 subjects) with iERM were imaged prospectively using FD-OCT with axial resolution of 4.5 μm and transverse resolution of 10 to 15 μm. MP-1 and Stratus OCT were carried out in a subset of eyes. The mean log of the minimum angle of resolution best-corrected visual acuity (BCVA) was 0.18±0.16 (range: -0.08 to 0.48, Snellen equivalent 20/15(-1) to 20/60). ERM was visualized in all 24 eyes with FD-OCT and in 17 eyes (85%) of 20 eyes imaged with Stratus OCT. Although BCVA correlated with macular thickening in the central 1 mm sub-field of the Stratus ETDRS (P=0.0005) and macular volume (central 3 mm area) on FD-OCT (P<0.0001), macular thickening on thickness map and volume correlated poorly with decrease in macular sensitivity on MP-1 (P=0.16). On FD-OCT, foveal morphological changes correlated best with decrease in BCVA, the strongest being central foveal thickness (P<0.0001). Other significant changes included blurring of the foveal inner segment-outer segment (IS-OS) junction and/or Verhoeff's membrane, vitreal displacement of foveal outer nuclear layer and foveal detachment (P<0.05). Foveal IS-OS junction disruption was seen in 25% of eyes on Stratus OCT but in none of the eyes on FD-OCT. FD-OCT allowed improved visualization of ERM and associated foveal morphological changes that correlated best with BCVA. Macular thickening correlated weakly with decreased macular function as assessed by MP-1.

High-Resolution Fourier-Domain Optical Coherence Tomography of Choroidal Neovascular Membranes Associated with Age-Related Macular Degeneration

To investigate the use of high-resolution Fourier-domain optical coherence tomography (Fd-OCT) to image choroidal neovascular membranes (CNVMs) associated with exudative age-related macular degeneration (eAMD). An Fd-OCT instrument with axial resolution of 4 to 4.5 microm and transverse resolution of 10 to 15 microm was used to image 21 eyes (19 subjects) with newly diagnosed eAMD. A raster series of 100 B-scans separated by 60 microm was used to study the growth pattern of CNVM and associated morphologic changes. CNVM size was determined using 250 to 300 serial virtual C-scans of reconstructed three-dimensional macular volume. A highly reflective subretinal and/or subretinal pigment epithelial (RPE) lesion that co-localized with the CNVM seen on fluorescein angiography was detected in all eyes by Fd-OCT. Although a combined subretinal and sub-RPE growth pattern of various degrees was noted in 15 (71%) eyes, a statistically significant difference in the distribution of growth pattern was noted when classic CNVM was compared with occult CNVM (chi(2) = 10.4, df = 2, P < 0.005). Classic lesions had >90% subretinal growth pattern, whereas occult lesions had a more variable growth pattern. Angiographic CNVM size correlated with size on Fd-OCT but correlation was better for classic CNVM (classic, r = 0.99, P < 0.0001; nonclassic, r = 0.78, P < 0.001). Fd-OCT is a promising potential alternative modality to visualize CNVM with AMD. Angiographic lesion size and type correlated with growth pattern and size of CNVM on Fd-OCT, with correlation being stronger for classic lesions.

Maculopathy associated with Prior Tamoxifen Use Diagnosed with Commercially Available Fourier-Domain Optical Coherence Tomography: A Case Series

Introduction: Tamoxifen retinopathy is usually diagnosed on fundoscopy and fluorescein angiography. Microcystoid maculopathy associated with tamoxifen was reported previously using a research-grade high resolution Fourierdomain optical coherence tomography (Fd-OCT) in a patient with vision loss unexplained on fundoscopy, fluorescein angiography and Stratus OCT. This report describes two new cases of microcystoid maculopathy diagnosed using commercially available Fd-OCT in patients who have been previously treated with tamoxifen. Case presentation: Two patients had visual complaints which started while on tamoxifen but persisted or worsened after stopping tamoxifen at least two years earlier. Both patients had normal or near normal visual acuity and fundoscopy. Fluorescein angiography was normal in all but one eye which showed foveal hyperfluorescence. No angiographic cystoid macular edema was noted. Commercially available Fd-OCT (RTVue and Cirrus) showed microcystoid changes in the central macula with patches of loss of photoreceptor inner segment-outer segment junction (IS-OS) near the fovea in all four eyes. The eye with foveal hyperfluorescence on fluorescein angiography had foveal detachment on Fd-OCT in addition which resolved spontaneously on follow-up Fd-OCT nine months later. The microcystoid changes and IS-OS loss persisted on follow-up Fd-OCT. Conclusion: Maculopathy associated with prior tamoxifen use may be detected using commercial Fd-OCT though not evident on fundoscopy or fluorescein angiography. Maculopathy may persist over 2 years after stopping tamoxifen.

MACULOPATHY DIAGNOSED WITH HIGH-RESOLUTION FOURIER-DOMAIN OPTICAL COHERENCE TOMOGRAPHY IN EYES WITH PREVIOUSLY UNEXPLAINED VISUAL LOSS

To describe maculopathy diagnosed with high-resolution Fourier-domain optical coherence tomography among eyes with previously unexplained visual loss. Nine eyes from six patients with previously unexplained vision loss based on funduscopy, fluorescein angiography, and Stratus optical coherence tomography and 32 eyes from 25 asymptomatic age-matched control subjects were imaged with a Fourier-domain optical coherence tomography instrument with axial resolution of 4 μm to 4.5 μm and transverse resolution of 10 μm to 15 μm. Among eyes with unexplained vision loss, visual acuity ranged from 20/20 to 20/80 and central scotoma was noted in all eyes by microperimetry or Amsler grid. Fourier-domain optical coherence tomography showed abnormality in the foveal photoreceptor (PR) layer in six eyes from four subjects (67%). These abnormalities include focal loss of the PR layer with microcystoid changes in the macula (n = 2), focal discontinuity of the PR layer (n = 3), and focal elevation and blurring of the PR layer associated with a mild epiretinal membrane (n = 1). Among age-matched control eyes, no foveal PR abnormality was seen. Fourier-domain optical coherence tomography detected subtle changes in the foveal PR layer in some eyes with vision loss and central scotoma unexplained with routine clinical diagnostic tests.

Noninvasive volumetric quality evaluation of post-surgical clear corneal incision via high-resolution Fourier-domain optical coherence tomography

A novel approach for post-surgical evaluation of clear corneal incision quality is presented. The complete volumetric information of an ex-vivo bovine cornea with incision and suture is obtained by high-resolution Fourier-domain optical coherence tomography and illustrated by various computer graphics technologies. This method provides more comprehensive information to evaluate surgery quality and monitor the healing process.

Reproducibility of Tear Meniscus Measurement by Fourier-Domain Optical Coherence Tomography: A Pilot Study

To study the reproducibility of tear meniscus measurement with high-speed high-resolution Fourier-domain optical coherence tomography (FD-OCT). Twenty normal participants were enrolled in this prospective study. The lower tear meniscus in the right eye of each subject was imaged by vertical scans centered on the inferior cornea and the lower eyelid using an FD-OCT system (RTVue; Optovue, Inc., Fremont, CA) with a corneal adaptor. The system performs 26,000 axial scans per second and has a 5-micron axial resolution. Each subject was examined at two visits 30 to 60 days apart. Each eye was scanned twice on each visit. The scans were taken 2 seconds after a blink. The lower meniscus height, depth, and cornea-meniscus angle were measured with a computer caliper. The cross-sectional area was calculated using a two-triangle approximation. The between-visits coefficient of variation was 17.5%, 18.0%, 35.5%, and 12.2% for meniscus height, depth, area, and angle, respectively. The intraclass correlations for these parameters were 0.605, 0.558, 0.567, and 0.367, respectively. FD-OCT measures lower tear meniscus dimensions and area with higher between-visits reproducibility than previous OCT instruments. FD-OCT may be a useful way to measure dry eye severity and treatment effectiveness.

Fine retinal striae associated with epiretinal membrane visualized using adaptive optics.

To describe a case of fine retinal striae visualized using an adaptive optics flood illuminated (AO-flood) fundus camera in a patient with vision loss from an idiopathic macular epiretinal membrane (ERM). A case report of a 48-year-old woman with recent vision loss from ERM imaged using an AO-flood fundus camera and high resolution Fourier-domain optical coherence tomography (Fd-OCT) before and 3 months after vitrectomy. Visual acuity improved from 20/70 to 20/20 after vitrectomy. Preoperative Fd-OCT showed severe cystoid macular edema with irregularities in the outer nuclear layer which consists of cell bodies of photoreceptors. Preoperative AO-flood en face images showed dark linear striae of approximately 10 μm width overlying the cone mosaic that improved following surgery, concurrent with improvement in visual acuity and morphologic changes on Fd-OCT. Microstructural changes within the retinal layers resulting from macular traction from ERM can be visualized using an AO-flood fundus camera and Fd-OCT. They can appear as fine linear striae in AO-flood en face images. Further studies are needed to correlate these changes with vision loss associated with this condition.

MICROCYSTOID MACULOPATHY ASSOCIATED WITH TAMOXIFEN USE DIAGNOSED BY HIGH-RESOLUTION FOURIER-DOMAIN OPTICAL COHERENCE TOMOGRAPHY

To describe a case of microcystoid maculopathy diagnosed by high-resolution Fourier-domain optical coherence tomography (Fd-OCT) in a patient treated with tamoxifen who had previously unexplained vision loss. Report of a case of a 66-year-old woman treated with tamoxifen for 4 years who had progressive unexplained vision loss in the left eye for 2 years. Visual acuity was 20/25 in the right eye and 20/70 in the left eye. Findings of funduscopy and fluorescein angiography were unremarkable except for minimal pigment alteration in the macula in the left eye. Stratus OCT showed possible microcystoid changes in the fovea in both eyes. Fd-OCT revealed scattered intraretinal microcystoid changes and patches of focal loss of photoreceptors in the macula in both eyes with foveal involvement in the left eye. Full-field electroretinogram was normal. Multifocal electroretinogram showed some decreased response in the peripheral macula and borderline low foveal response in both eyes. Microcystoid maculopathy associated with tamoxifen use can be diagnosed by Fd-OCT in a normal appearing fundus. It can present as unexplained vision loss.

Detailed analysis of retinal function and morphology in a patient with autosomal recessive bestrophinopathy (ARB)

The objective of the paper is to study the retinal microstructure and function in a patient with autosomal recessive bestrophinopathy (ARB). Retinal function and morphology assessment in a patient diagnosed with a biallelic mutation in the BEST1 gene (heterozygote mutations: Leu88del17 and A195V) included: full-field electroretinogram (ffERG) and multifocal electroretinogram (mfERG), electro-oculogram (EOG) testing, and imaging with a high-resolution Fourier-domain optical coherence tomography (Fd-OCT) system (UC Davis Medical Center; axial resolution: 4.5 microm, acquisition speed: 9 frames/s, 1,000 A-scans/frame) combined with a flexible scanning head (Bioptigen Inc.). The 11-year old asymptomatic boy showed a well-demarcated retinopathy with deposits. Functional assessment revealed normal visual acuity, reduced central mfERG responses, delayed rod and rod-cone b-wave ffERG responses, and reduced light rise in the EOG. Fd-OCT demonstrated RPE deposits, photoreceptor detachment, elongated and thickened photoreceptor outer segments, but preserved inner retinal layers. In conclusion, ARB associated retinal dystrophy shows functional and morphological changes that overlap with classic Best disease. For the first time, high-resolution imaging provided in vivo evidence of RPE and photoreceptor involvement in ARB.

High-speed, high-resolution Fourier-domain optical coherence tomography system for retinal imaging in the 1060 nm wavelength region

A high-speed (47,000 A-scans/s), ultrahigh axial resolution Fourier domain optical coherence tomography (OCT) system for retinal imaging at approximately 1060 nm, based on a 1024 pixel linear array, 47 kHz readout rate InGaAs camera is presented. When interfaced with a custom superluminescent diode (lambda(c) = 1020 nm, Deltalambda = 108 nm, Pout = 9 mW), the system provides 3.3 microm axial OCT resolution at the surface of biological tissue, approximately 4.5 microm in vivo in rat retina, approximately 5.7 microm in vivo in human retina, and 110 dB sensitivity for 870 microW incident power and 21 mus integration time. Retinal tomograms acquired in vivo from a human volunteer and a rat animal model show clear visualization of all intraretinal layer and increased penetration into the choroid.

High-resolution Fourier-Domain Optical Coherence Tomography and Microperimetric Findings After Macula-off Retinal Detachment Repair

To evaluate the morphologic changes in the macula of subjects with repaired macula-off retinal detachment (RD) using high-resolution Fourier-domain optical coherence tomography (FD OCT) and to perform functional correlation in a subset of patients using microperimetry (MP-1). Prospective observational case series. Seventeen eyes from 17 subjects who had undergone anatomically successful repair for macula-off, rhegmatogenous RD at least 3 months earlier and without visually significant maculopathy on funduscopy. FD OCT with axial and transverse resolution of 4.5 mum and 10 to 15 mum, respectively, was used to obtain rapid serial B-scans of the macula, which were compared with that from Stratus OCT. The FD OCT B-scans were used to create a 3-dimensional volume, from which en face C-scans were created. Among 11 patients, MP-1 was performed to correlate morphologic changes with visual function. Stratus OCT scans, FD OCT scans, and MP-1 data. Stratus OCT and FD OCT images of the macula were obtained 3 to 30 months (mean 7 months) postoperatively in all eyes. Although Stratus OCT revealed photoreceptor disruption in 2 eyes (12%), FD OCT showed photoreceptor disruption in 13 eyes (76%). This difference was statistically significant (P<0.001, chi(2)). Both imaging modalities revealed persistent subretinal fluid in 2 eyes (12%) and lamellar hole in 1 eye. Among 7 subjects who had reliable MP-1 data, areas of abnormal function corresponded to areas of photoreceptor layer disruptions or persistent subretinal fluid in 5 subjects (71%); one subject had normal FD OCT and MP-1. Photoreceptor disruption after macula-off RD repair is a common abnormality in the macula that is detected better with FD OCT than Stratus OCT. A good correlation between MP-1 abnormality and presence of photoreceptor disruption or subretinal fluid on FD OCT demonstrates that these anatomic abnormalities contribute to decreased visual function after successful repair.

Retinal Morphological Changes of Patients With X-linked Retinoschisis Evaluated by Fourier-Domain Optical Coherence Tomography

To investigate the retinal microstructure and lamination of patients affected with X-linked retinoschisis (XLRS) using high-resolution imaging modalities. Patients diagnosed as having XLRS underwent assessment. Visual function testing included visual acuity, color vision, and full-field electroretinography. We used a high-resolution Fourier-domain optical coherence tomography (FD-OCT) system (4.5-mum axial resolution; 9 frames/s; 1000 A-scans per frame) combined with a handheld scanner. Macular image evaluation included schisis localization and retinal layer integrity. Six patients with XLRS and identified mutations in the XLRS1 gene underwent testing. Visual acuity ranged from 0.2 to 1.6 logMAR (logarithm of the minimum angle of resolution). Results of FD-OCT revealed foveal schisis extending from the outer to the inner plexiform layer in 4 of 6 patients. Bullous foveal schisis was associated with younger age. All patients showed extrafoveal schisis within the outer and inner nuclear and ganglion cell layer, alone or in combination. Photoreceptor outer and inner segment layers were disrupted and irregular in all patients. Retinal dystrophy in XLRS is reflected by morphological changes within the inner and outer retinal layers. Disturbed foveal photoreceptor integrity was identified in all patients. Retinal layer abnormalities correlated with age but did not appear to correlate with visual acuity or genotypic variation.

Changes in Cellular Structures Revealed by Ultra-high Resolution Retinal Imaging in Optic Neuropathies

To study the integrity of inner and outer retinal layers in patients with various types of optic neuropathy by using high-resolution imaging modalities. Three high-resolution imaging systems constructed at the University of California Davis were used to acquire retinal images from patients with optic neuropathy: (1) adaptive optics (AO)-flood-illuminated fundus camera, (2) high-resolution Fourier domain optical coherence tomography (FDOCT), and (3) adaptive optics-Fourier domain optical coherence tomography (AO-FDOCT). The AO fundus camera provides en face images of photoreceptors whereas cross-sectional images (B-scans) of the retina are obtained with both FDOCT and AO-FDOCT. From the volumetric FDOCT data sets, detailed thickness maps of a three-layer complex consisting of the nerve fiber (NF), ganglion cell (GC), and inner plexiform (IP) layers were created. The number of visible cones in the en face images of photoreceptors was then compared with visual sensitivity maps from Humphrey visual field (HVF; Carl Zeiss Meditec, Inc., Dublin, CA) testing, as well as FDOCT and AO-FDOCT images, including the thickness maps of the NF-GC-IP layer complex. Five types of optic neuropathy were studied: (1) optic neuritis with multiple sclerosis (MS), (2) idiopathic intracranial hypertension (pseudotumor cerebri), (3) nonarteritic anterior ischemic optic neuropathy (NAION), (4) optic nerve head drusen with NAION, and (5) systemic lupus erythematosus with MS and arthritis. With permanent visual field loss and thinning of the NF-GC-IP layer complex, cone photoreceptors showed structural changes, making them less reflective, which caused the appearance of dark spaces in the en face images (hence, reduced number of visible cones) and indistinct outer retinal layers in OCT images. However, when the visual field loss was only transient, with a normal NF-GC-IP layer complex, there were no detectable abnormalities in cone photoreceptors (i.e., they were densely packed and had distinct photoreceptor layering in the OCT images). Cone photoreceptors show structural changes when there is permanent damage to overlying inner retinal layers. There was a positive relation between the thickness of the three-layer inner retinal complex, visual sensitivity, and integrity of the cone mosaic.

High-speed and wide bandwidth Fourier domain mode-locked wavelength swept laser with multiple SOAs

We report on the development of a high-speed, wide bandwidth Fourier domain mode-locked (FDML) wavelength swept laser of around 1300 nm using two gain media for high-resolution and high-speed Fourier domain optical coherence tomography. The wavelength swept laser is capable of FWHM scanning range of more than 135 nm at 45.6 kHz sweeping rate. The measured axial resolution of the forward scan is 6.6 microm in air and 4.7 microm in tissue. The peak power is 11.4 mW for both the forward and backward scans. The measured system sensitivity is achieved up to 100.7 dB. We also demonstrate OCT imaging using the FDML wavelength swept laser with two semiconductor optical amplifiers.

High-Resolution Imaging of Complicated LASIK Flap Interface Fluid Syndrome

The authors report a case of post-LASIK interface fluid syndrome that led to epithelial ingrowth, a sequelae that had not been reported to date. The interface fluid was caused by steroid-induced ocular hypertension. On post-LASIK day 49, the interface fluid, epithelial ingrowth, and noncellular reflective deposits were visualized by confocal microscopy and high-resolution Fourier-domain optical coherence tomography. No inflammatory cells or infectious organisms were seen. These high-resolution imaging technologies were useful in the noninvasive evaluation of the location and nature of flap interface pathologies at the microstructural level.