Optical Coherence Tomography Sections Research Articles

Visual prognosis of eyes with submacular hemorrhage associated with exudative age-related macular degeneration

To study the retinal structural changes associated with submacular hemorrhage due to exudative age-related macular degeneration (AMD) and their relationships with visual prognosis. We retrospectively reviewed the medical records of 31 consecutive patients (31 eyes) with visual impairment due to an acute submacular hemorrhage associated with typical AMD (10 eyes) or polypoidal choroidal vasculopathy (21 eyes). Optical coherence tomography (OCT) revealed that submacular hemorrhage exhibited intense hyperreflectivity beneath the neurosensory retina and often seemed to infiltrate it. In the OCT sections, mild to moderate amorphous hyperreflectivity and/or hyperreflective dots were observed within the neurosensory retina, resulting in the loss of the junctions between the inner (IS) and outer (OS) segments of the photoreceptors. Of the 31 eyes, the foveal IS/OS line could be seen incompletely in 12 eyes and was totally absent in 16 eyes. The initial integrity of the foveal photoreceptor layer was correlated with the final visual acuity; the initial detection of the IS/OS just beneath the fovea was correlated with good final visual acuity (r = 0.375, p = 0.038). As a hallmark of integrity of the foveal photoreceptor layer, the initial detection of the IS/OS just beneath the fovea may predict good visual outcomes.

Morphologic and Functional Changes in Retinal Vessels Associated with Branch Retinal Vein Occlusion

To study the morphologic and functional changes in retinal veins of eyes affected with branch retinal vein occlusion (BRVO) by thin sectioning with optical coherence tomography (OCT). Prospective, observational, cross-sectional study. Twenty-five consecutive patients (25 eyes) with acute BRVO. Major retinal veins, arteries, and arteriovenous (A/V) crossing were examined by sequential thin sectioning by Spectralis HRA+OCT (Heidelberg Engineering, Heidelberg, Germany). The retinal blood flow was mimicked in vitro and scanned with Spectralis HRA+OCT. Morphologic characteristics of normal and BRVO-affected retinal vessels seen in OCT sections. Cross-sectional OCT images revealed physiologic retinal vessels as oval configurations with 4 distinctive hyperreflectivities in a line. The vessel walls showed the innermost and outermost hyperreflectivity, and the blood flow showed internal paired hyperreflectivities with an hourglass shape. No eye with disturbed blood flow due to BRVO showed this internal hyperreflectivity pattern. In vitro, OCT sections of the blood within the glass tube without flow showed homogeneous reflectivities. Increased blood flow velocity resulted in the development of heterogeneous internal reflectivity and hourglass-shaped hyperreflectivities. In all eyes with acute BRVO, sequential sectioning with OCT visualized 3-dimensional vascular architecture and the intravascular conditions at the A/V crossing. At the affected A/V crossing, arterial overcrossing was seen in 17 eyes and venous overcrossing was seen in 8 eyes. In eyes with arterial overcrossing, the retinal vein seemed to run deep under the artery at the A/V crossing, and the venous lumen often appeared to be preserved even at the A/V crossing. In all eyes with venous overcrossing, the retinal vein appeared to be compressed and choked between the internal limiting membrane and the arterial wall at the A/V crossing. Optical coherence tomography sectioning showed intravenous thrombi in 21 eyes, and the thrombi were detected downstream of the A/V crossing in all the cases. The detection of thrombus was significantly associated with ischemic pattern in BRVO (P=0.036). In eyes with BRVO, sequential thin sections with OCT visualized 3-dimensional retinal vasculature. The present OCT findings suggest that BRVO may occur by 2 different mechanisms, depending on the relative anatomic positions of the crossing vessels. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Retinal thinning in tree shrews with induced high myopia: Optical coherence tomography and histological assessment

This study determined retinal thinning in a mammalian model of high myopia using optical coherence tomography (OCT) and histological sections from the same retinal tissue. High myopia was induced in three tree shrews ( Tupaia belangeri) by deprivation of form vision via lid suture of one eye, with the other eye a control. Ocular biometry data was obtained by Ascan ultrasonography, keratometry and retinoscopy. The Zeiss StratusOCT was used to obtain Bscans in vivo across the retina. Subsequently, eyes were enucleated and retinas fixed, dehydrated, embedded and sectioned. Treated eyes developed a high degree of axial myopia (−15.9 ± 2.3 D; n = 3). The OCT analysis showed that in myopic eyes the nasal retina thinned more than the temporal retina relative to the disc ( p = 0.005). Histology showed that the retinas in the myopic eyes comprise all layers but were thinner than the retinas in normal and control eyes. Detailed thickness measurements in corresponding locations of myopic and control eyes in superior nasal retina using longitudinal reflectivity profiles from OCT and semithin vertical histological sections showed the percentage of retinal thinning in the myopic eyes was similar between methods (OCT 15.34 ± 5.69%; histology 17.61 ± 3.02%; p = 0.10). Analysis of retinal layers revealed that the inner plexiform, inner nuclear and outer plexiform layers thin the most. Cell density measurements showed all neuronal cell types are involved in retinal thinning. The results indicate that in vivo OCT measurements can accurately detect retinal thinning in high myopia.

Interobserver variability for retreatment indications after Ranibizumab loading doses in neovascular age-related macular degeneration

To assess the interobserver variability (IOV) in indicating retreatment for neovascular Age-related macular degeneration 4 weeks after three Ranibizumab loading doses using spectral domain OCT (SD-OCT) as the primary objective diagnostic tool. Four observers decided for or against 4th Ranibizumab injection in 108 patients by six different rating rounds (RR) based on the SD-OCT findings after the loading doses. Postoperative OCT images were supplemented consecutively with information from a chart review as the 'patients subjective estimation of vision (SE)', the course of best-corrected visual acuity (BCVA) and the preoperative OCT as well as all information collectively. Agreement rates (AR) and Kappa statistics were calculated. Based on post-treatment OCT findings only (RR1), mean reinjection rate of all observers was 37.5%. Adding supplementary information, mean reinjection rate decreased to 20% when all information was available reflecting the 'real' situation (RR 6). Interobserver agreement rates varied from 66.7% to 90.7% depending on rating rounds and interobserver pairs. Mean AR and Kappa values (KV) were as following: AR 81.6%, KV 0.61 (RR1: 'only post-OP OCT'); AR 76.7%, KV 0.33 (RR2: post-OP OCT + SE); AR 80.3%, KV 0.45 (RR3: post-OP OCT + BCVA); AR 80.7%, KV 0.46 (RR4: pre- and post-OP OCT); AR 82.2%, KV 0.49 (RR5: post-OP OCT + SE + BCVA); and finally AR 83.6%, KV 0.47 (RR6: pre- and post-OP OCT + SE + BCVA). The overall mean agreement rate was 80.9% with a Kappa of 0.47. IOV for indicating retreatment after three Ranibizumab loading doses reveals only moderate agreement in Kappa statistics, which seems to be too low considering the high costs for retreatments. More concise guidelines based on the post-treatment OCT scans as the presumably most sensitive and noninvasive objective tool to follow choroidal neovascularization activity by judging the course of sub- and intraretinal fluid are necessary.

Seröz Makula Dekolmanına Yol Açan Aktif Oküler Toksoplazmozisteki Optik Koherens Tomografi Bulguları

In this study we present the structural vitreoretinal changes observed during the clinical follow-up of a 35-year-old female patient presenting with serous macular detachment complicated with active ocular toxoplasmosis. The patient applied to the ophthalmology outpatient clinic with the complaint of impaired vision in the left eye; during her clinical follow-up her active toxoplasma chorioretinitis and accompanying serous macular detachment (SMD) in the macula of the same eye were evaluated with optical coherence tomography (OCT). In the OCT sections encompassing the active lesion, there was increased reflectance and thickening in posterior hyaloid membrane and retinal layers as well as local fluid collection in the subretinal space. Secondary to increased retinal reflectance, retinal pigment epithelium-choriocapillaris junction demonstrated focal shadowing. The clinical findings of the patient improved with treatment. During her control OCT examination, it was seen that posterior hyaloid membrane at the site of the lesion was detached, collected fluid underneath the retina was resolved, retinal tissue became thinner with irregular layers and the suppressed reflectance of the retinal pigment epithelium-choriocapillaris junction was partially improved. OCT sections at the level of macula demonstrated total disappearance of SMD.

Hyperreflective Sign in Resolved Cotton Wool Spots Using High-Resolution Optical Coherence Tomography and Optical Coherence Tomography Ophthalmoscopy

To characterize retinal changes in areas of cotton wool spots (CWSs) using optical coherence tomography (OCT) and to determine the optical density changes of the retina after CWSs have disappeared clinically. Prospective, noninterventional, observational study. Thirty-one patients with CWSs who underwent imaging studies. The study groups included patients with CWSs resulting from diabetic retinopathy (n = 12), human immunodeficiency virus (HIV) retinopathy (n = 10), hypertensive retinopathy (n = 3), branch retinal vein occlusion (n = 3), uveitis (n = 2), and radiation retinopathy (n = 1). The single line scan mode of the StratusOCT Model 3000 (Carl Zeiss Meditec, Dublin, CA) was used for imaging of acute CWSs, CWSs 3 months after their resolution, and adjacent normal retina. A fundus photograph served as a template for localization of OCT scanning of CWSs. Retinal tissue reflectivity images were compared across lesion types and time. Additional imaging in 14 patients was performed to localize lesions better and to provide coronal OCT sections using the combined OCT and scanning laser ophthalmoscope. Changes in retinal reflectivity in areas of normal retina and retina with acute and resolved CWSs. The average reflectivity of normal retina was 58.4+/-2.1 dB, the average reflectivity in the area of active CWSs was 62.6+/-2.5 dB, and the average reflectivity in the same area after CWSs resolved was 61.0+/-2.4 dB. A significant difference (P<0.05) exists between reflectivity of normal retina and acute CWSs as well as normal retina and resolved CWSs. Acute CWSs show a hyperreflective pattern on OCT. As they become ophthalmoscopically invisible, the OCT still shows signs of hyperreflectivity in the areas of previous CWSs (hyperreflective sign). The authors observed the same phenomenon using 2 imaging machines.

Catheter-based intraluminal optical coherence tomography (OCT) of the ureter: ex-vivo correlation with histology in porcine specimens

Intraluminal optical coherence tomography (OCT) applies coherent light to provide cross-sectional images with a spatial resolution of 10-25 microm. We compared OCT and matching whole-mount histology microscopy sections of porcine upper ureters ex vivo for visualization and delineation of different tissue layers of the ureteral wall. Porcine ureters (six specimens, 24 quadrants) were flushed with normal saline solution prior to insertion of the OCT catheter (diameter, 0.014 inch, OCT wavelength, 1,300+/-20 nm). Cross-sectional OCT images were obtained in marked locations before specimens were fixed in 4% formalin, cut at marked locations, whole-mounted, and stained with hematoxilin and eosin. Visualization and delineation of different tissue layers of the ureteral wall by OCT was compared with matching histology by two independent observers (O1,O2). OCT distinguished tissue layers of the ureteral wall in all quadrants. In OCT images, O1/O2 delineated urothelium and lamina propria in 23/24 quadrants, lamina propria and muscle layer in 19/16 quadrants, inner and outer muscle layer in 13/0 quadrants, and urothelial cell layers in 13/2 quadrants, respectively. Intraluminal OCT provides histology-like images of the ureter in porcine specimens ex vivo and reliably distinguishes between urothelium and deeper tissue layers of the ureteral wall.

Optical coherence tomographic findings in pregnancy-associated central serous chorioretinopathy

To report the presence and disappearance of subretinal fibrinous exudate in pregnancy-induced central serous chorioretinopathy studied with optical coherence tomography (OCT). Case report. A 32-year-old woman was referred for ophthalmoscopic evaluation in her 32nd week of pregnancy, complaining of reduced vision in her right eye. The funduscopic examination revealed a serous detachment of the macula with subretinal exudative deposits in the right eye and a peripapillary serous detachment in the left eye. OCT sections through the right macula demonstrated serous elevation of the retina and the presence of highly reflective material in the subretinal space. Two weeks after delivery, OCT showed resolution of subretinal fluid and the disappearance of submacular exudate in the right eye. During pregnancy and immediately after delivery, OCT may provide information reflecting the relationship between the retina, subretinal space, and retinal pigment epithelium without any known adverse effects to the infant. In a patient with pregnancy-associated central serous chorioretinopathy, a highly reflective material, presumably fibrin, was detected spanning the subretinal space that was subsequently shown to disappear. This information may help us better understand the pathological retinal changes that may occur during pregnancy.

Structural features of attached retina in rhegmatogenous retinal detachments.

To examine the thickness and structural features of the ophthalmoscopically normal-appearing, attached retina in rhegmatogenous retinal detachments by optical coherence tomography (OCT) and compare them with those of the fellow eye. Seventy eyes of 35 patients with rhegmatogenous retinal detachments were included in this study. The retinal detachments were not total. None of the patients had pathologic myopia or a history of ocular surgery. The fellow eyes were ophthalmoscopically normal and used as controls. Attached retinal sites of the eyes with a retinal detachment and the corresponding retinal sites of the fellow eyes were examined by OCT. Three OCT sections were taken from each eye, and thicknesses of three reflective zones corresponding to the inner part of the neurosensory retina (partial neurosensory retina), photoreceptor-photoreceptor outer segment, and total retinal thickness on each OCT section were measured and compared with those of the fellow eye. These three measurements were taken as the main outcome measures and performed on five different sites of each OCT section taken from each eye. The mean partial neurosensory retinal thickness of the attached retina in the eyes with a retinal detachment and the corresponding retinal sites in the fellow eyes was 172.74 +/- 14.23 microm and 170.60 +/- 16.51 microm, respectively. There was no statistically significant difference between these two values. The mean photoreceptor outer segment thickness of the attached retina in the eyes with a retinal detachment and the corresponding retinal sites in the fellow eyes was 62.74 +/- 12.02 microm and 58.23 +/- 15.14 microm, respectively. There was a statistically significant difference between these two values. The mean total retinal thickness of the still-attached retina in the eyes with a retinal detachment and the corresponding retinal sites in the fellow eyes were 293.23 +/- 27.87 microm and 277.06 +/- 19.12 microm, respectively. There was a statistically significant difference between these two values. The main difference between the two groups of eyes was at the level of the thickness of the black hyporeflective zone, corresponding anatomically to the photoreceptor and photoreceptor outer segment that enlarges in the retinal detachments. Therefore, there may be a subclinical retinal detachment or a global retinal relaxation even in the ophthalmoscopically normal-appearing, still-attached retina. This may be the underlying cause of preoperative and postoperative signs and symptoms. Additional studies are required to confirm these findings.