Ignacio Flores-Moreno

Direct comparison of spectral-domain and swept-source OCT in the measurement of choroidal thickness in normal eyes

Objective To compare spectral-domain optic coherence tomography (SD-OCT) and swept-source OCT (SS-OCT) in the study of choroidal thickness (CT) in healthy eyes. Methods Prospective, cross-sectional, single-centre study. 82 healthy eyes of 46 patients were included. In a single session, Topcon 3D-2000 SD-OCT and 1050 nm SS-OCT prototype devices were used to perform OCT scans using a single line protocol. Two masked investigators independently, manually determined 13 CT measurements consisting of one subfoveal (SFCT), and six measurements on either side of the fovea (nasal and temporal) taken every 500 microns apart. The mean CT (MCT) was the mean average of these 13 measurements. Results SD-OCT was able to reproducibly measure the CT in 74.4% of eyes vs 100% with SS-OCT (p<0.05; Fishers Exact test). In those eyes measured by both systems, mean SFCT was 279.4±96.9 μm (range, 84–506) with SD-OCT vs 285.7±88.9 μm (range 130–527) with SS-OCT (p=0.11; Students t test paired data). Mean MCT was 243.8±78.8 μm (range 103.6–433.2) with SD-OCT vs 242.2±81.8 μm (range 97.6–459) with SS-OCT (p=0.64; Students t test paired data). The difference in SFCT and MCT was not statistically significant between both devices. Intraclass correlation coefficient was higher than 0.9 interobserver and interdevice measurements. SFCT Bland–Altman plots showed 95% interobserver measurement agreement within ±34 for SD-OCT, ±22 for SS-OCT and ±60 μm intersystems. Conclusions SS-OCT permitted accurate identification of the choroido-scleral border in 100% of normal eyes, suggesting that SS-OCT was the superior modality for the measurement of CT.

The relationship between retinal and choroidal thickness and visual acuity in highly myopic eyes

Background/aims To correlate visual acuity in highly myopic eyes without macular disease with retinal and choroidal thickness as measured by spectral-domain optical coherence tomography (OCT). Methods 60 eyes of 46 highly myopic patients (spherical equivalent ≥−6 D or axial length ≥26 mm) were studied in a clinical setting. Eyes with any clinical evidence of maculopathy or amblyopia were excluded. Eyes were imaged using the 3D-2000 OCT (Topcon Corporation, Tokyo, Japan). Two independent investigators manually measured: choroidal thickness at 500-μm intervals up to 2500-μm nasal and temporal to the fovea, subfoveal choroidal thickness, foveal thickness, outer nuclear layer and photoreceptors in addition to retinal pigment epithelium (RPE). Statistical analysis was performed. Results Mean age was 45.9±17.9 years (range 18–99), mean best-corrected visual acuity (BCVA) LogMAR was 0.11±0.19 (range 0–1), mean axial length was 28.2±2.4 mm (range 26–35.3) and mean spherical equivalent was −12.05±5.02 D (range −6 to −26). Mean macular choroidal thickness was 157±84.6 μm (range 16.7–426.5), mean subfoveal choroidal thickness was 166±88.7 μm (range 13.5–486.5), mean foveal thickness was 221.1±30.3 μm (range 157.5–296), mean outer nuclear layer was 121.3±22.6 μm (range 74–191.5) and mean photoreceptors in addition to RPE was 99.5±10.8 μm (range 71.5–115.5). BCVA (LogMAR) negatively correlated with macular choroidal thickness (r=−0.371, p=0.003), subfoveal choroidal thickness (r=−0.358, p=0.004) and photoreceptors and RPE aggregate (r=−0.346, p=0.006). Conclusions Subfoveal choroidal thickness, mean macular choroidal thickness and outer retinal thickness are the most important predictive factors of visual acuity in highly myopic eyes without macular pathology. Outer nuclear layer and foveal thickness are not related to visual acuity.

Effect of Intravitreous Anti–Vascular Endothelial Growth Factor Therapy on Choroidal Thickness in Neovascular Age-Related Macular Degeneration Using Spectral-Domain Optical Coherence Tomography

A critical method of monitoring patients with neovascular age-related macular degeneration (AMD) being treated with anti–vascular endothelial growth factor (anti-VEGF) is optical coherence tomography (OCT), which uses low-coherence interferometry of light to examine the retina in vivo on a micrometer scale.1 Recent advances in spectral-domain OCT make visualization of the choroid feasible. Using image averaging and enhanced depth imaging, successful examination and measurement of choroidal thickness in normal and pathologic states have been reported.2–4 It has been hypothesized that anti-VEGF may affect choroidal vasculature.5 The goal of this study is to evaluate the effect of anti-VEGF on choroidal thickness using spectral-domain OCT in treatment-naive subjects.

En face swept-source optical coherence tomography in neovascular age-related macular degeneration.

Purpose To describe en face swept-source optical coherence tomography (SS-OCT) findings in the retinal pigment epithelium (RPE) and choroid and to correlate them with fluorescein angiography (FA) and/or indocyanine green angiography (ICGA) in neovascular age-related macular degeneration (AMD). Methods Thirty-eight eyes with the recent diagnosis of neovascular AMD were imaged using an SS-OCT system. En face images were obtained at RPE, choriocapillaris, Sattlers layer and Hallers layer level. Analysis of the images and correlation with colour fundus photographs, FA, ICGA in selected cases, were made. Results En face images at RPE level revealed changes in all eyes. The neovascular complex appeared hyper-reflective in 9 of 38 eyes (23.7%), and in 29 of 38 eyes (76.3%), it was hyporeflective. The choriocapillaris en face image showed pathological changes in all eyes as well, and in 20 out of 38 eyes (52.6%), the alterations were hyper-reflective, while 18 of 38 eyes (47.4%) showed hyporeflective changes. Twenty (52.6%) eyes and 19 (50.0%) had a hyper-reflective lesion in Sattlers layer and Hallers layer, respectively, and 15 (39.4%) cases showed a hyporeflective lesion in both layers. No differences were found between the neovascular complex area, horizontal and vertical diameters, measured in the en face image and FA (p=0.171, p=0.061, p=0.133, respectively). Hyporeflective changes were predominant at RPE level and hyper-reflective at choriocapillaris, Sattlers and Hallers layers. Conclusions En face SS-OCT is a rapid, non-invasive, high-resolution, promising technology, which allows a complementary study to angiography of neovascular AMD. There is a correlation between angiography and en face SS-OCT images in neovascular AMD.

ASYMMETRY IN MACULAR CHOROIDAL THICKNESS PROFILE BETWEEN BOTH EYES IN A HEALTHY POPULATION MEASURED BY SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY.

Purpose: To determine the difference in macular choroidal thickness (CT) profile between eyes in healthy individuals using swept-source optical coherence tomography. Design: Cross-sectional noninterventional study. Participants: One hundred and forty eyes from 70 healthy patients with spherical equivalent between ±3 D and with difference ⩽0.25 D between eyes were scanned using a swept-source optical coherence tomography (Topcon Corporation). Methods: Cross-sectional noninterventional study. One hundred and forty eyes from 70 healthy patients with spherical equivalent between ±3 D and with difference #0.25 D between eyes were scanned using a swept-source optical coherence tomography (Topcon Corporation). A horizontal CT profile of the macula was created in both eyes by manually measuring the subfoveal CT from the posterior edge of retinal pigment epithelium (RPE) to the choroid/sclera junction. Three determinations were performed at successive points 1,000 mm nasal to the fovea and 5 more temporal to the fovea. The differences in CT between both eyes were analyzed. Results: Mean age was 25.4 ± 19.9 years (from 4 to 75). The mean spherical equivalent was 0.18 ± 1.37 D (from −3 to +3). Mean macular nasal CT was thicker in the right eye (RE) than in the left eye (LE) (228.11 ± 69.23 &mgr;m vs. 212.27 ± 62.71 &mgr;m; P = 0.0002; Students t-test paired data). Mean subfoveal CT and mean temporal CT was not statistically significantly different between the eyes. No statistically significant differences were observed comparing spherical equivalent in the RE compared with the LE. Both men and women showed a thicker mean nasal choroid in the RE versus the left (men, 226.97 ± 61.56 &mgr;m vs. 209.87 ± 60.31 &mgr;m; women, 229.63 ± 79.39 &mgr;m vs. 215.47 ± 66.68 &mgr;m, P = 0.003 and P = 0.03, respectively; Students t-test paired data). At each nasal determination, CT in the RE was statistically significantly thicker than the LE (N1: 283.72 ± 81.10 &mgr;m vs. 269.76 ± 75.81 &mgr;m [P = 0.001]; in N2: 230.45 ± 73.47 &mgr;m vs. 211.33 ± 66.92 &mgr;m [P = 0.0002]; and in N3: 170.16 ± 61.00 &mgr;m vs. 155.72 ± 53.87 &mgr;m [P = 0.008], respectively). Conclusion: To the best of our knowledge, this is the first report suggesting thicker macular nasal choroid in the RE compared with the LE. In contrast, subfoveal CT and temporal CT were not found to be different between eyes.

En face mode of swept-source optical coherence tomography in circumscribed choroidal haemangioma

Purpose To describe the findings in circumscribed choroidal haemangioma (CCH) using en face swept-source optical coherence tomography (SS-OCT). Methods En face images were obtained employing DRI-1 Atlantis OCT (Topcon, Tokyo, Japan), using a three-dimensional volumetric scan of 12×9 mm. Images were obtained from the retinal pigment epithelium to 1000 μm in depth of the tumour. Results Twenty-two eyes from 22 patients with the clinical diagnosis of CCH were included. In 20 eyes (90.9%), a characteristic pattern was visualised in the en face image across the vascular tumour. A multilobular pattern, similar to a honeycomb, with hyporeflective, confluent, oval or round areas corresponding with the lumen of the tumour vascular spaces, and hyper-reflective zones, which may represent the vessels walls and connective tissue of the tumour. Ten eyes (45.4%) showed a hyper-reflective halo surrounding the tumour. Seventeen tumours (77.2%) showed small diameter vessels at the inner zone and larger vessels in the outer area. Twelve patients (54.5%) had previously received treatment (photodynamic therapy, transpupillary thermotherapy, dexamethasone intravitreal implant or brachytherapy with ruthenium-106). No differences were found between treated and untreated patients in any of the measured parameters. Conclusions En face SS-OCT is a rapid, non-invasive, high-resolution, technology, which allows a complementary study to cross-sectional scans in CCH. A characteristic multilobular pattern, with a hyper-reflective halo surrounding the tumour, was found in en face SS-OCT images. No morphological differences were found between naïve patients and patients who received previous treatment.

INTRAVITREAL DEXAMETHASONE IMPLANT FOR RADIATION MACULOPATHY SECONDARY TO PLAQUE BRACHYTHERAPY IN CHOROIDAL MELANOMA.

Purpose: To evaluate the efficacy of intravitreal dexamethasone implant 0.7 mg (Ozurdex) in radiation maculopathy secondary to plaque brachytherapy in choroidal melanoma. Methods: Twelve eyes diagnosed of radiation maculopathy secondary to plaque brachytherapy and treated with intravitreal dexamethasone implant were included. Visual acuity, foveal thickness using spectral domain optical coherence tomography, and grade of macular edema, using Horgan classification, were evaluated. Results: Mean age was 65.5 ± 28 years (range, 40–82 years). Mean follow-up was 8.2 ± 7.8 months (range, 2–28 months). Mean visual acuity before treatment was, in logarithm of the minimum angle of resolution scale, 1 ± 0.58 (range, 0.4–2) and mean final visual acuity 0.8 ± 0.58 (range, 0.2–2), showing a nonsignificant trend to improvement (P = 0.091; Wilcoxons test). Foveal thickness before treatment was 416 ± 263 &mgr;m (range, 222–725 &mgr;m) and final foveal thickness 254 ± 170 &mgr;m (range, 145–750), showing a significant decrease (P = 0.016; Wilcoxons test). Referring to Horgan classification, a significant reduction in grades before and after treatment was demonstrated (P = 0.007; Wilcoxons test). Conclusion: Ozurdex is a useful treatment for radiation maculopathy associated to plaque brachytherapy for uveal melanoma, with a significant decrease in foveal thickness and a significant improvement in Horgan classification. This anatomical improvement was correlated with a moderate improvement in visual acuity.

ANALYSIS OF AGE-RELATED CHOROIDAL LAYERS THINNING IN HEALTHY EYES USING SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY.

Purpose: To study the changes in the choroidal layers thickness with age in a healthy population using swept-source optical coherence tomography. Methods: Retrospective data analysis of a subgroup of eyes from a previous single-center, prospective, cross-sectional, noninterventional study. One hundred and sixty-nine healthy eyes were evaluated using swept-source optical coherence tomography. Inclusion criteria were best-corrected visual acuity between 20/20 and 20/25, spherical equivalent between ±3 diopters, and no systemic or ocular diseases. Two independent investigators determined the macular horizontal choroidal thickness (CT) and the Hallers layer thickness across a 9 mm line centered at the fovea. Subjects were divided into five age groups. Results: Mean subfoveal choroidal thickness was 305.76 ± 80.59 &mgr;m (95% confidence interval: 294.85–319.33). Mean subfoveal thickness for Hallers layer was 215.47 ± 67.70 &mgr;m (95% confidence interval: 207.30–227.86) and mean subfoveal thickness for choriocapillaris plus Sattlers layer was 87.31 ± 40.40 &mgr;m (95% confidence interval: 83.38–95.65). No significant differences were found due to gender. Choroidal thickness profile was similar between groups with choroidal thickness and Hallers layer thickness decreasing with age (P = 0.002). Conclusion: Choroidal and Hallers layer thickness profiles are similar between different age groups. Age-related choroidal thinning is mostly at the expense of Hallers layer.

The Prevalence of Vitreomacular Interface Pathology in a Spanish Tertiary Hospital

Purpose: To determine the prevalence of vitreomacular interface (VMI) pathology, using spectral-domain optical coherence tomography (SD-OCT). Methods: VMI status was classified into macular posterior vitreous detachment (PVD), focal vitreomacular adhesion (VMA; ≤1,500 μm), broad VMA (>1,500 μm), focal vitreomacular traction (VMT; ≤1,500 μm), broad VMT (>1,500 μm), full-thickness macular hole (FTMH) with the presence of VMT, and FTMH without the presence of VMT. Results: A total of 1,976 eyes were included. A nonpathologic VMI was observed in 1,875 eyes (94.8%), including 1,050 (53.1%) with PVD, 120 (6.1%) with focal VMA and 705 (35.6%) with broad VMA. A pathologic state of the VMI was diagnosed in 101 eyes (5.1%). Thirty-three eyes (1.7%) were classified as focal VMT, 29 (1.4%) as broad VMT, 39 (1.9%) as FTMH, resulting in 6 small, 12 medium and 21 large FTMHs, six eyes had VMT associated to FTMH. Conclusions: Even in a tertiary care, retinal referral practice, VMI pathology is a relatively rare condition. There was a higher prevalence in a tertiary hospital study compared to population-based studies.

Intraocular Tumors Using Swept Source OCT

Swept source optical coherence tomography (SS-OCT) permits a complementary study of retinal and choroidal lesions and diseases, including intraocular tumors. Due to the longer wavelength (1050 nm) employed, SS-OCT allows the visualization of the internal configuration of the tumors, and even the extent of the lesion in small and medium tumors, up to a thickness of around 500 μm in pigmented lesions and up to 1600 μm in non-pigmented lesions [1, 2]. The high-quality images and resolution obtained with SS-OCT allow a better study of the tumors, helping at the time of diagnosis and showing complementary information such as intraretinal edema, subretinal fluid, photoreceptor atrophy, and retinal pigment epithelium (RPE) atrophy or detachments, which will guide physicians to the best treatment.