SD OCT Research Articles

Microcystic macular edema in optic nerve atrophy: case series

AbstractPurpose Microcystic macular edema (MME) is a new entity defined as lacunar areas of hyporeflectivity in the retinal inner nuclear layer after severe optic neuropathy (ON). Initially, MME was fortuitously discovered in optic neuritis.Methods From July 2013, we imaged all patients with ON by SD OCT. Retinal nerve fiber layer thickness (RNFLT), macular cube thickness (MCT) and retinal ganglion cell layer thickness (RGCLT) were assessed. Studied parameters included also the delay between onset of ON and detection of MME and correlation of the visual field defect to the MME topography.Results Sixteeen patients (19 eyes) exhibited MME. Etiologies of ON were compressive (7), degenerative (4), inflammatory (3), ischemic (1), and hereditary (1). There were 9 women and 7 men, mean age at diagnosis being 34.1 years. Visual acuity ranged from NLP to 12/10 (median 4/10). Mean RNFLT was 61.6µm [97+/‐10µm], mean MCT 271.37µm [261+/‐18µm] and mean RGCLT 57.22µm [82+/‐7µm]. The time from diagnosis until MME detection ranged from 4 months to 23 years. A good correlation was found between the zone of retinal atrophy on infrared photography and MME distribution. However, only 4/16 visual field defects correlated to the MME topography.Conclusion MME can occur as early as 4 months after ON (ocular trauma in our series) and can persist as late as 23 years after the onset of ON. MME is not only related to inflammatory ON, as postulated initially, but is a nonspecific manifestation from ON of any etiology. The precise mechanism leading to MME is unknown but trans‐synaptic retrograde degeneration is likely. Why only 10% of patients with ON exhibit MME is unknown, but MME might be a transient phenomenon. Further clinical and experimental studies are needed to answer these questions.

Performance characteristics of multicolor versus blue light and infrared imaging in the identification of reticular pseudodrusen

AbstractPurpose To describe the appearance of reticular pseudodrusen (RPD) on multicolor imaging (MC) and to evaluate its diagnostic accuracy as compared with the two modalities considered the current reference standard, blue light (BL) and infrared (IR).Methods A retrospective study reviewing all multicolor images of a series of consecutive patients. Inclusion criteria involved the presence of > 1 RPD on a 30º x 30º image centered on the fovea as seen with the BL channel derived from the multicolor imaging of the Spectralis HRA+OCT ®. The diagnosis of RPD was confirmed by the identification of subretinal debris on a tracking‐assisted SD OCT Heidelberg. A 3.0 mm diameter circle divided in 4 fields (S, N, I and T) was overlaid on each image and manually centered on the foveola. Three experienced observers, masked to their own results with other imaging modalities, independently classified the number of RPD in each field in each image with each modality, according to this classification: Category 0: 0‐5 RPD ; 1: 6‐20; 2: 21‐35; 3: 36‐49; and 4: >50. Friedman and Wilcoxon tests were used for the comparison between different imaging modalities per field by the same observer. The kappa (K) coefficient was used to measure interobserver agreementResults MC and IR modalities showed higher sensitivity and interobserver agreement in RPD detection than BL. No clinically significant differences were found between multicolor and IR.Conclusion Multicolor imaging modality (the new index test) can play an important role in the identification, quantification and categorization of RPD when compared to the reference standard test (images of BL and IR), a result which is still the subject of much debate.

Three-Dimensional Automated Choroidal Volume Assessment on Standard Spectral-Domain Optical Coherence Tomography and Correlation With the Level of Diabetic Macular Edema

To measure choroidal thickness on spectral-domain optical coherence tomography (SD OCT) images using automated algorithms and to correlate choroidal pathology with retinal changes attributable to diabetic macular edema (DME). Post hoc analysis of multicenter clinical trial baseline data. SD OCT raster scans/fluorescein angiograms were obtained from 284 treatment-naïve eyes of 142 patients with clinically significant DME and from 20 controls. Three-dimensional (3D) SD OCT images were evaluated by a certified independent reading center analyzing retinal changes associated with diabetic retinopathy. Choroidal thicknesses were analyzed using a fully automated algorithm. Angiograms were assessed manually. Multiple endpoint correction according to Bonferroni-Holm was applied. Main outcome measures were average retinal/choroidal thickness on fovea-centered or peak of edema (thickest point of edema)-centered Early Treatment Diabetic Retinopathy Study grid, maximum area of leakage, and the correlation between retinal and choroidal thicknesses. Total choroidal thickness is significantly reduced in DME (175 ± 23 μm; P = .0016) and nonedematous fellow eyes (177 ± 20 μm; P = .009) of patients compared with healthy control eyes (190 ± 23 μm). Retinal/choroidal thickness values showed no significant correlation (1-mm: P = .27, r(2) = 0.01; 3-mm: P = .96, r(2) < 0.0001; 6-mm: P = .42, r(2) = 0.006). No significant difference was found in the 1- or 3-mm circle of a retinal peak of edema-centered grid. All other measurements of choroidal/retinal thickness (DME vs healthy, DME vs peak of edema-centered, DME vs fellow, healthy vs fellow, peak of edema-centered vs healthy, peak of edema-centered vs fellow eyes) were compared but no statistically significant correlation was found. By tendency a thinner choroid correlates with larger retinal leakage areas. Automated algorithms can be used to reliably assess choroidal thickness in eyes with DME. Choroidal thickness was generally reduced in patients with diabetes if DME is present in 1 eye; however, no correlation was found between choroidal/retinal pathologies, suggesting different pathogenetic pathways.

Improvement of lateral resolution of spectral domain optical coherence tomography images in out-of-focus regions with holographic data processing techniques

An analogy between spectral-domain optical coherence tomography (SD OCT) data and broadband digital holography data is considered. Based on this analogy, a method for processing SD OCT data, which makes it possible to construct images with a lateral resolution in the whole investigated volume equal to the resolution in the in-focus region, is developed. Several issues concerning practical application of the proposed method are discussed.

Outer Retinal Tubulation in the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT)

To determine the prevalence of, risk factors for, and visual acuity (VA) correlations with outer retinal tubulation (ORT) seen on spectral-domain optical coherence tomography (SD OCT) in eyes with neovascular age-related macular degeneration (AMD) after anti-vascular endothelial growth factor (VEGF) therapy. Prospective cohort study within a randomized clinical trial. Patients with SD OCT images at weeks 56 and 104 in the Comparison of AMD Treatments Trials (CATT). Participants in the CATT were assigned randomly to ranibizumab (0.5 mg) or bevacizumab (1.25 mg) treatment and to a monthly or pro re nata (PRN) injection-dosing regimen. A subset of eyes was imaged with SD OCT beginning at week 56. Cirrus 512×128 or Spectralis 20°×20° volume cube scan protocols were used to acquire SD OCT images. Two independent readers at the CATT OCT reading center graded scans, and a senior reader arbitrated discrepant grades. The prevalence of ORT, identified as tubular structures seen on at least 3 consecutive Cirrus B scans or 2 consecutive Spectralis B scans, was determined. The associations of patient-specific and ocular features at baseline and follow-up with ORT were evaluated by univariate and multivariate analyses. Outer retinal tubulations. Seven of 69 eyes (10.1%) at 56 weeks and 64 of 368 eyes (17.4%) at week 104 had ORTs. Absence of diabetes, poor VA, blocked fluorescence, geographic atrophy, greater lesion size, and presence of subretinal hyperreflective material at baseline were associated independently with greater risk of ORT at 104 weeks (P < 0.05). Neither drug nor dosing regimen were associated significantly with ORT. The mean VA of eyes with ORT at week 104 (58.5 Early Treatment Diabetic Retinopathy Study letters) was worse than the mean VA of eyes without ORT (68.8 letters; P < 0.0001). At 2 years after initiation of anti-VEGF therapy for neovascular AMD, ORTs are present in a substantial proportion of eyes. We identified baseline features that independently predict ORTs. It is important to identify ORTs because eyes with ORTs have worse VA outcomes than those without this finding.

Epidemiology of Epiretinal Membrane in a Large Cohort of Patients with Uveitis

To identify clinical characteristics associated with the presence of epiretinal membrane (ERM) in patients with uveitis. Case-control study. Five hundred ninety-eight subjects seen in a single tertiary referral clinic between January 1, 2008, and December 31, 2011, who were diagnosed with uveitis. Spectral-domain optical coherence tomography (SD OCT) images of all subjects were reviewed to assess for ERM. A multivariate logistic regression analysis was performed to compare characteristics of subjects with ERM (cases) with characteristics of subjects without ERM (controls). A second multivariate analysis assessed the relationship between ERM and visual acuity. Fundus photographs were reviewed to compare SD OCT ascertainment of ERM with photographic ascertainment. Presence or absence of ERM on OCT imaging. Of 598 uveitic participants, 246 (41%) were found to have ERM in at least 1 eye on SD OCT imaging. The prevalence of ERM by Standardization of Uveitis Nomenclature anatomic subtype was 28.1% for anterior uveitis, 57.0% for intermediate uveitis, and 43.4% for posterior uveitis and panuveitis. Multivariate analysis showed that the following clinical factors were associated significantly with ERM: older age (3% increased risk per year of age; 95% confidence interval [CI], 1.02-1.05), intermediate uveitis (odds ratio [OR], 3.41; 95% CI, 1.67-6.96), posterior uveitis and panuveitis (OR, 1.81; 95% CI, 1.09-3.01), male sex (OR, 1.59; 95% CI, 1.05-2.42), and history of cataract surgery (OR, 1.78; 95% CI, 1.13-2.79). When adjusted for covariates, eyes with ERM had a mean logarithm of the minimum angle of resolution visual acuity of 0.58 (20/76) versus 0.48 (20/60) in non-ERM eyes (P = 0.039). Of OCT-defined ERMs in this cohort, 38% were not detectable on fundus photographs. Epiretinal membrane is a common complication of uveitis that is associated with patient age, intermediate uveitis, posterior uveitis, panuveitis, male sex, and previous cataract surgery. It can contribute independently to vision loss in uveitic eyes. In uveitis, OCT is more sensitive than fundus photography for identification of ERM.

The Lack of Concordance Between Subretinal Drusenoid Deposits and Large Choroidal Blood Vessels

To evaluate the concordance between pseudodrusen as manifested by subretinal drusenoid deposits and large choroidal blood vessels using stereological analysis of spectral-domain optical coherence tomography (SD OCT) images. Retrospective, observational case series. The SD OCT images of 31 consecutive patients with the clinical appearance of pseudodrusen from a private-referral retinal clinic were retrospectively reviewed. A grid of 19 evenly spaced vertical lines was randomly superimposed on each SD OCT image using ImageJ to perform systematic uniform random sampling. The main outcome measure was the likelihood of association between subretinal drusenoid deposits and large choroidal vessels. Uniform random systematic sampling of 589 samples found the proportion of geometric probes intersecting subretinal drusenoid deposits to be 0.28, large choroidal vessel 0.65, and both 0.19. This value was nearly identical to the product of the joint probabilities and was within the 95% confidence interval (0.15-0.21) of the point estimate as calculated by the binomial theorem, indicating mutual independence. The subretinal drusenoid deposits were associated with neither large choroidal vessels nor the intervals in between. Our results demonstrate that there is no concordance between subretinal drusenoid deposits and large choroidal vessels or the stroma in between. As a consequence, hypotheses postulating that subretinal drusenoid deposits are associated with large choroidal vessels or the choroidal stromal spaces should be abandoned. Stereological techniques are powerful methods used in image evaluation in other fields of study and appear to have utility in analyzing OCT findings of the retina and choroid.

Achromatic registration of quadrature components of the optical spectrum in spectral domain optical coherence tomography

We have thoroughly investigated the method of simultaneous reception of spectral components with the achromatised quadrature phase shift between two portions of a reference wave, designed for the effective suppression of the ‘mirror’ artefact in the resulting image obtained by means of spectral domain optical coherence tomography (SD OCT). We have developed and experimentally tested a phase-shifting element consisting of a beam divider, which splits the reference optical beam into the two beams, and of delay lines being individual for each beam, which create a mutual phase difference of in the double pass of the reference beam. The phase shift achromatism over a wide spectral range is achieved by using in the delay lines the individual elements with different dispersion characteristics. The ranges of admissible adjustment parameters of the achromatised delay line are estimated for exact and inexact conformity of the geometric characteristics of its components to those calculated. A possibility of simultaneous recording of the close-to-quadrature spectral components with a single linear photodetector element is experimentally confirmed. The suppression of the artefact mirror peak in the OCT-signal by an additional relative to the level of its suppression is experimentally achieved when the air delay line is used. Two-dimensional images of the surface positioned at an angle to the axis of the probe beam are obtained with the correction of the ‘mirror’ artefact while maintaining the dynamic range of the image.

Optical Coherence Tomography–Based Measurement of Drusen Load Predicts Development of Advanced Age-Related Macular Degeneration

To determine whether baseline drusen load, as measured using spectral-domain optical coherence tomography (SD OCT), is a useful predictor of development of advanced age-related macular degeneration (AMD). Retrospective cohort study. setting: Academic clinical practice. study population: All patients with non-neovascular AMD and no retinal pigment epithelial (RPE) atrophy at baseline who were seen between 2007 and 2012 in a single academic retina practice. A minimum of 1 year of follow-up was required. observation: Drusen load (area and volume) was assessed using automated SD OCT software algorithms. main outcome measure: RPE atrophy area, assessed using an automated SD OCT software algorithm, and the development of neovascular AMD. Eighty-three patients met the inclusion criteria with a mean age of 80 years and a mean follow-up time of 2.8 years. Repeated-measures analysis of variance showed an association between drusen area (P = .005) and drusen volume (P = .001) and the development of RPE atrophy. We also found an association between drusen area (P = .001) and drusen volume (P = .001) and the development of neovascular AMD. Drusen load, as measured using SD OCT, is associated with the development of RPE atrophy and neovascular AMD. SD OCT assessments of drusen load are simple and practical measurements that may be useful in stratifying the risk of developing advanced AMD. These measurements have potential applications in both routine clinical care and clinical trials.

GPU-accelerated non-uniform fast Fourier transform-based compressive sensing spectral domain optical coherence tomography.

We implemented the graphics processing unit (GPU) accelerated compressive sensing (CS) non-uniform in k-space spectral domain optical coherence tomography (SD OCT). Kaiser-Bessel (KB) function and Gaussian function are used independently as the convolution kernel in the gridding-based non-uniform fast Fourier transform (NUFFT) algorithm with different oversampling ratios and kernel widths. Our implementation is compared with the GPU-accelerated modified non-uniform discrete Fourier transform (MNUDFT) matrix-based CS SD OCT and the GPU-accelerated fast Fourier transform (FFT)-based CS SD OCT. It was found that our implementation has comparable performance to the GPU-accelerated MNUDFT-based CS SD OCT in terms of image quality while providing more than 5 times speed enhancement. When compared to the GPU-accelerated FFT based-CS SD OCT, it shows smaller background noise and less side lobes while eliminating the need for the cumbersome k-space grid filling and the k-linear calibration procedure. Finally, we demonstrated that by using a conventional desktop computer architecture having three GPUs, real-time B-mode imaging can be obtained in excess of 30 fps for the GPU-accelerated NUFFT based CS SD OCT with frame size 2048(axial) × 1,000(lateral).

A Longitudinal Comparison of Spectral-Domain Optical Coherence Tomography and Fundus Autofluorescence in Geographic Atrophy

To identify reliable criteria based on spectral-domain optical coherence tomography (SD OCT) to monitor disease progression in geographic atrophy attributable to age-related macular degeneration (AMD) compared with lesion size determination based on fundus autofluorescence (FAF). Prospective longitudinal observational study. setting: Institutional. study population: A total of 48 eyes in 24 patients with geographic atrophy. observation procedures: Eyes with geographic atrophy were included and examined at baseline and at months 3, 6, 9, and 12. At each study visit best-corrected visual acuity (BCVA), FAF, and SD OCT imaging were performed. FAF images were analyzed using the region overlay device. Planimetric measurements in SD OCT, including alterations or loss of outer retinal layers and the RPE, as well as choroidal signal enhancement, were performed with the OCT Toolkit. main outcome measures: Areas of interest in patients with geographic atrophy measured from baseline to month 12 by SD OCT compared with the area of atrophy measured by FAF. Geographic atrophy lesion size increased from 8.88mm² to 11.22mm² based on quantitative FAF evaluation. Linear regression analysis demonstrated that results similar to FAF planimetry for determining lesion progression can be obtained by measuring the areas of outer plexiform layer thinning (adjusted R(2)= 0.93), external limiting membrane loss (adjusted R(2)= 0.89), or choroidal signal enhancement (R(2)= 0.93) by SD OCT. SD OCT allows morphologic markers of disease progression to be identified in geographic atrophy and may improve understanding of the pathophysiology of atrophic AMD.

Optical Coherence Tomography Retinal Thickness and Volume Measurements in X-Linked Retinoschisis

To analyze retinal thickness and volume measurements of X-linked retinoschisis patients by spectral-domain optical coherence tomography (SD OCT) and correlate these findings with visual acuity and patient age. Retrospective comparative case series. Sixty-three eyes of 33 male patients with X-linked retinoschisis were gleaned from a SD OCT database at the University of Illinois at Chicago. Forty-one eyes of 21 patients with low refractive error, no visualimpairment, and no known retinal disease served as age-similar controls. The mean age of the retinoschisis patients was 26.4 years. The mean age of patient controls was 30.0 years. Full-thickness, inner and outer retina thickness, and volume measurements were determined by SD OCT. Foveal schisis was observed in 81% of retinoschisis patients. Patients with foveal schisis tended to be younger than patients lacking foveal schisis. Inner and outer foveal thickness and volume measurements were increased in retinoschisis patients compared to controls. Outer retinal perifoveal and parafoveal thicknesses and volumes were consistently increased in retinoschisis patients relative to controls. In contrast, inner retinal perifoveal and parafoveal thickness and volume measurements were decreased in retinoschisis patients compared to controls. Worse visual acuity correlated with thinning of the temporal perifoveal inner retina and thickening of the inner fovea. Full-thickness measurements and inner retina and outer retina thickness and volume measurements tended to decrease with patient age. Increased inner retinal foveal thickness and decreased perifoveal inner retinal thickness correlates with worse visual acuity and overall retinal thickness decreases with age in X-linked retinoschisis.

Suppression of Intraocular Vascular Endothelial Growth Factor During Aflibercept Treatment of Age-Related Macular Degeneration

To determine the duration of suppression of aqueous humor concentrations of vascular endothelial growth factor (VEGF) in eyes with neovascular age-related macular degeneration (AMD) treated with aflibercept. Nonrandomized prospective clinical study. Twenty-seven eyes of 27 neovascular AMD patients receiving intravitreal aflibercept injections on a pro re nata regimen driven by spectral-domain optical coherence tomography (SD OCT) were included in this study. A total of 132 aqueous humor specimens were collected before intravitreal aflibercept injections and their VEGF-A concentrations assayed by multiplex bead analysis. Mean aqueous humor VEGF concentrations before treatment initiation were 90.6 ± 37.1 pg/mL (range 23.4-190.3 pg/mL). Intravitreal injection of aflibercept suppressed the aqueous VEGF concentrations to below the lower limit of quantification (<4 pg/mL) in all patients. The mean duration of VEGF suppression below the lower limit of quantification was >71 ± 18 days. The earliest time after injection at which the VEGF concentration recovered to above the lower limit of quantification was 55 days in 1 patient and >56 days, the recommended aflibercept treatment interval, in 20 patients. The aqueous VEGF recovery status of 6 patients was uncertain after 56 days. On average, VEGF concentrations in the aqueous humor were suppressed below the lower limit of quantification after intravitreal aflibercept injections for about 10 weeks. This aqueous suppression time suggests durable VEGF inhibition for most patients dosed with aflibercept every 8 weeks.

Foveal Structure–Function Correlation in Children With History of Retinopathy of Prematurity

To correlate visual acuity to macular spectral-domain optical coherence tomography (SD OCT) anomalies detected in children with a history of retinopathy of prematurity (ROP). Retrospective cohort study. All charts of children with a history of ROP between 2 and 18 years of age and with SD OCT performed between 2010 and 2012 were reviewed. Central foveal thickness was measured and correlated with visual acuity. Secondary outcome measures included temporal parafoveal thickness, presence of the inner nuclear layer and outer segment, gestational age at birth, sex, spherical equivalent, history of laser treatment, and developmental delay. The study included 44 better-seeing eyes of 44 patients. Sixty-four percent (28/44) of patients in our study had 20/40 or better visual acuity despite an abnormal foveal morphology in 91% of total eyes. Patients with a history of ROP demonstrate a high frequency of macular morphologic abnormalities, including retention of inner retinal layers and absent foveal depression, on SD OCT. These structural changes do not always correlate to visual acuity. Instead it appears that cone maturation may be a better indicator of visual acuity. In addition, there is a significant correlation between best-corrected visual acuity and myopia.

Radial Versus Raster Spectral-Domain Optical Coherence Tomography Scan Patterns for Detection of Macular Pathology

To compare the 6-line radial vs the 25-line raster spectral-domain optical coherence tomography (SD OCT) acquisition patterns at detecting intraretinal fluid, subretinal fluid, vitreomacular traction, and full-thickness macular hole (MH). Retrospective cross-sectional analysis. Series of 365 eyes with neovascular age-related macular degeneration (AMD), diabetic macular edema (DME), central and branch retinal vein occlusion (CRVO/BRVO), central serous chorioretinopathy, vitreomacular traction, and full-thickness MH. Sequential 6-line radial and 25-line raster scans were evaluated for intraretinal/subretinal fluid and, when applicable, vitreomacular traction and MH. For neovascular AMD (133 scans), 7 25-line raster scans confirmed subretinal/intraretinal fluid not identified by the 6-line radial (P=.02). For DME (140 scans) and central serous chorioretinopathy (91 scans), 25-line raster confirmed fluid in 4 scans (P=.13) and 1 scan (P=.32), respectively, that was not observed with the 6-line radial. For CRVO (123 scans) and BRVO (126 scans), 25-line raster confirmed fluid on 2 (P=.25) and 4 scans (P=.13), respectively, that was not detected by the 6-line radial. Conversely, for focal vitreomacular traction (70 scans) and full-thickness MH (82 scans), 25-line raster missed focal traction (<1500 μm) and MH in 5 scans (P=.07) and 7 scans (P=.02), respectively, that were identified using the 6-line radial. The 6-line radial scan is statistically comparable to the 25-line raster at detecting fluid in DME, BRVO/CRVO, and central serous chorioretinopathy, but not neovascular AMD. Furthermore, it is superior to the 25-line raster pattern at detecting early MH formation, while demonstrating a positive trend in identifying focal vitreomacular traction.

Gray Hyper-Reflective Subretinal Exudative Lesions in Exudative Age-Related Macular Degeneration

To investigate the effects of ranibizumab 0.5 mg on gray hyper-reflective subretinal lesions diagnosed by spectral-domain optical coherence tomography (SD OCT) in patients with exudative age-related macular degeneration (AMD). Retrospective interventional study. Data from 28 consecutive patients affected with neovascular AMD that presented subretinal hyper-reflective lesions as visualized by SD OCT were collected. Gray hyper-reflective subretinal lesion characteristics were analyzed before and after intravitreal ranibizumab 0.5 mg injection. Thirty eyes of 28 patients (5 male, 23 female, aged 57-91 years) were included. At study entry, gray lesion was associated with exudative features in 24 of 30 eyes (80%), including subretinal fluid (SRF) in 20 of 30 eyes (67%) and retinal cystoid spaces in 11 of 30 eyes (37%). Twenty-four eyes with exudative features at study entry received prompt treatment; 6 eyes without exudative features at study entry received deferred treatment (after 1 month observation), when exudative signs emerged (SRF in 3/6 eyes and retinal cystoid spaces in 5/6 eyes). Ninety-three percent of the gray lesions responded to ranibizumab treatment at 2 months and 77% at 6 months. Gray hyper-reflective subretinal lesion thickness was significantly reduced after treatment at both 2 months (from 482±116 μm to 367±102 μm, P<.0001) and 6 months (from 482±116 μm to 369±71 μm, P<.0001). Our findings suggest that gray hyper-reflective subretinal lesions might be considered as a qualitative criterion for retreatment of exudative AMD. They may represent an early sign of active choroidal neovascularization, and should prompt to early treatment.

Spectral-Domain Optical Coherence Tomography Epithelial and Flap Thickness Mapping in Femtosecond Laser–Assisted In Situ Keratomileusis

To evaluate the change of epithelial and flap thickness after femtosecond laser-assisted in situ keratomileusis (LASIK) using spectral-domain optical coherence tomography (SD OCT) in correlation with the spherical equivalent refraction treated and clinical outcomes. Prospective, randomized, contralateral-eye study. Forty myopic eyes underwent LASIK using an excimer laser with refraction ranging from -1.00 to -7.25 diopters (mean -3.25±1.9). Flap creation was randomized between eyes, using the IntraLASE FS60 laser (IL) in 1 eye and WaveLight FS200 laser (FS) in the contralateral eye. SD OCT was used to evaluate the epithelial and flap thickness profiles and corneal power preoperatively and at 1 week and 1, 3, and 9 months postoperatively. Manifest and wavefront refractions were performed at each postoperative visit. Statistically significant epithelial thickening was observed in both IL and FS groups as early as 1 month postoperatively (P=.033 and P=.042), but this stabilized between 3 (P=.042 and P=.035) and 9 months (P=.043 and P=.041). Femtosecond-LASIK flaps were thicker in the IL group in comparison to the FS group at 3 and 9 months postoperatively (P=.003 and P=.005, respectively). There was a statistically significant correlation between the magnitude of preoperative myopic refraction and the central epithelial thickness at 1, 3, and 9 months (Pearson correlation coefficients 0.485, 0.587 and 0.576) (P=.0021, P=.0010, and P=.0011), respectively. SD OCT corneal power maps showed steepening at 3 and 9 months along with mild myopic shift. Progressive epithelial and flap thickening with increased corneal power were observed after femtosecond laser-assisted in situ keratomileusis for myopia with consequent stabilization between 3 to 9 months postoperatively. The magnitude of epithelial and flap thickness remodeling correlated to the preoperative myopic refractive error.

Ghost Maculopathy: An Artifact on Near-Infrared Reflectance and MultiColor Imaging Masquerading as Chorioretinal Pathology

To describe the features of an artifact on near-infrared reflectance and MultiColor imaging, termed "ghost maculopathy," and to illustrate how it may masquerade as true chorioretinal pathology. This was a retrospective, observational case series. The authors studied 144 eyes of 72 consecutive patients in a vitreoretinal clinical practice, reviewing multimodal imaging including color and red-free fundus photography, fundus autofluorescence (FAF), near-infrared reflectance, MultiColor imaging, and spectral-domain optical coherence tomography (SD OCT). In 36 of 144 eyes (25%), there was an appearance of a hyper-reflective spot on near-infrared reflectance and MultiColor imaging, located at the macula, nasal or superonasal to the fovea, which did not correspond to any apparent lesion on color and red-free fundus photography, FAF, or SD OCT. This spot was termed the "ghost image" in this phenomenon of "ghost maculopathy." The ghost image was present consistently on near-infrared reflectance and MultiColor imaging in all 36 eyes at every imaging encounter, showing minimal and subtle variability in its shape and location within each eye; however, it showed large interindividual variability in size, shape, location, and reflectivity between different eyes. Nine eyes were found to have a similar hyper-reflective spot resembling that in ghost maculopathy, but corresponding SD OCT images were consistent with diagnoses of choroidal nevus, age-related macular degeneration, and multifocal choroiditis. All eyes with ghost maculopathy were found to be pseudophakic with a posterior chamber intraocular lens. Ghost maculopathy is the phenomenon of an imaging artifact appearing at the macula on near-infrared reflectance and MultiColor imaging that occurs predominantly in pseudophakic patients and may be mistaken for true chorioretinal pathology. Awareness of this artifact is prudent to avoid misinterpretation of clinical findings and possible unnecessary over-investigation.

Pseudocystic Foveal Cavitation in Tamoxifen Retinopathy

To present 3 cases of tamoxifen-induced foveal cavitation and review previous prospective and cross-sectional studies. Observational case series. Retrospective analysis of patients presenting to a single institution with evidence of tamoxifen-induced maculopathy. Three patients presented with pseudocystic foveal cavitation similar in appearance to macular telangiectasia type 2 on spectral-domain optical coherence tomography (SD OCT) imaging. Tamoxifen maculopathy is characterized by cavitation in the central macula with or without typical cystoid macular edema. Pathogenesis involves toxicity to retinal Müller cells. It can occur with low daily and cumulative doses of the drug, and in the absence of subjective visual complaints or crystalline retinopathy. Prospective research with SD OCT imaging will be required to gain a more accurate estimate of the incidence of tamoxifen retinopathy.

Pseudodrusen Subtypes as Delineated by Multimodal Imaging of the Fundus

To subclassify pseudodrusen based on their appearance in multimodal imaging. Retrospective, observational series. The color fundus photographs and infrared scanning laser ophthalmoscope (IR-SLO) images of patients with pseudodrusen were evaluated along with spectral-domain optical coherence tomography (SD OCT) by masked readers. Distinct types of pseudodrusen could be differentiated. There were 140 eyes of 93 patients with a mean age of 82.4 years. Multimodal imaging analysis showed 3 subtypes of pseudodrusen. One principal type was an orderly array of whitish discrete accumulations principally located in the perifovea, termed dot pseudodrusen. They appeared as hyporeflective spots, often with a target configuration, in IR-SLO images. The second type was interconnected bands of yellowish-white material forming a reticular pattern, called ribbon pseudodrusen, which were located in the perifovea. This subtype was faintly hyporeflective in IR-SLO imaging. Dot pseudodrusen were detected more commonly with IR-SLO imaging than in color photography (P= .014) and ribbon pseudodrusen were seen more frequently in color than in IR-SLO images (P < .001). An uncommon third type of pseudodrusen, yellow-white globules primarily located peripheral to the perifoveal region, appeared hyper-reflective in IR-SLO and were called peripheral pseudodrusen. All 3 types were seen as subretinal drusenoid deposits by SD OCT. Pseudodrusen may be classified into at least 3 categories, each with optimal methods of detection and only 1 that formed a reticular pattern. These findings suggest pseudodrusen could contain differing constituents and therefore may vary in conferred risk for progression to advanced age-related macular disease.