1,720,977 research outputs found
A novel navigated laser system brings new efficacy to the treatment of retinovascular disorders
Get PDFThe laser photocoagulation is now treatment of choice for various retinovascular disorders. Conventional slit-lamp based laser delivery systems have many limitations including, questionable accuracy, need of contact lens with local anesthesia, and inadvertent damage to fovea. Navigated laser system, a fundus camera based laser delivery system with computer based laser planning and laser treatment without contact lens achieves improved patient compliance, improved accuracy, and treatment ease for the physician, efficient panretinal photocoagulation pattern laser, excellent documentation, and advanced laser training. This article compares navigated laser systems with available conventional and PASCAL laser systems based on the literature and personal experience of the authors
Choroidal volume variations with age, axial length, and sex in healthy subjects: a three-dimensional analysis
No full textPurpose: To demonstrate the 3-dimensional choroidal volume distribution in healthy subjects using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD-OCT) and to evaluate its association with age, sex, and axial length. Design: Retrospective case series. Participants: A total of 176 eyes from 114 subjects with no retinal or choroidal disease. Methods: The EDI SD-OCT imaging studies of healthy patients who had undergone a 31-raster scanning protocol on a commercial SD-OCT device were reviewed. Manual segmentation of the choroid was performed by 2 retinal specialists. A macular choroidal volume map and 3-dimensional topography were automatically created by the built-in software of the device. Mean choroidal volume was calculated for each Early Treatment Diabetic Retinopathy Study (ETDRS) subfield. Regression analyses were used to evaluate the correlation between macular choroidal volume and age, sex, and axial length. Main Outcome Measures: Three-dimensional topography and ETDRS-style volume map of the choroid. Results: Three-dimensional topography of the choroid and volume map was obtained in all cases. The mean choroidal volume was 0.228±0.077 mm3 for the center ring and 7.374±2.181 mm3 for the total ETDRS grid. The nasal quadrant showed the lowest choroidal volume, and the superior quadrant showed the highest choroidal volume. The temporal and inferior quadrants did not show different choroidal volume values. Choroidal volume in all the EDTRS rings was significantly correlated with axial length after adjustment for age (P < 0.0001), age after adjustment for axial length (P < 0.0001), and sex after adjustment for axial length (P < 0.05). Choroidal volume decreases by 0.54 mm3 (7.32%) for every decade and by 0.56 mm3 (7.59%) for every millimeter of axial length. Male subjects have a 7.37% greater choroidal volume compared with that of female subjects. Conclusions: Enhanced depth imaging SD-OCT is a noninvasive and well-tolerated procedure with an excellent ability to visualize 3-dimensional topography of the choroid and to measure choroidal volume at the posterior pole using manual segmentation. Age and axial length are inversely correlated with choroidal volume, most likely leading to changes in retinal metabolic support in elderly, highly myopic patients. Sexual differences should be considered when interpreting an EDI SD-OCT scan of the choroid. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article
Significance of the hyperautofluorescent ring associated with choroidal neovascularisation in eyes undergoing anti-VEGF therapy for wet age-related macular degeneration
No full textAim To characterise the presence of a hyperautofluorescent (HAF) ring associated with choroidal neovascularisation (CNV) complex in patients with wet age-related macular degeneration (AMD).
Methods Fundus autofluorescence images and spectral-domain optical coherence tomography (OCT) scans from 362 eyes with wet AMD were reviewed. The presence and size of an HAF ring associated with the CNV complex was evaluated. A subgroup of 64 treatment-naive eyes with new-onset CNV was studied to analyse the relationship between pretreatment OCT characteristics and the presence of the HAF ring.
Results An HAF ring was present in 38% of the entire cohort of eyes and in 39% of treatment-naive eyes. The presence of the HAF ring was significantly correlated with the extent of baseline subretinal fluid (SRF) on OCT (p=0.0113), the number of antivascular endothelial growth factor (VEGF) injections (p=0.0439) and the number of treatment cycles (p=0.0154). Eyes with an HAF ring were more likely to have disruption of the ellipsoid zone line once the SRF was resolved compared with eyes without an HAF ring (p=0.0002). In multivariate analysis, the best predictors for HAF ring were the baseline area of SRF (p=0.0449) and the number of anti-VEGF treatments received (p=0.0568).
Conclusions Nearly 40% of wet AMD eyes had an HAF ring. In treatment-naive eyes, the HAF ring had a significant association with SRF and was found as early as the baseline measurement and as long as 18months after beginning treatment, persisting for up to 6years after the initial diagnosis. Its association with baseline SRF and disruption of the ellipsoid zone line of the photoreceptors on OCT could indicate continuous stress on the outer retinal structures after exposure to prolonged SRF and/or transmitted autofluorescence from loss of the photoreceptors overlying the retinal pigment epithelium
Temporal pattern of resolution/recurrence of choroidal neovascularization during bevacizumab therapy for wet age-related macular degeneration
No full textAIM: To characterize temporal pattern of resolution and recurrence of naive choroidal neovascularization (CNV) secondary to wet age-related macular degeneration (AMD) treated with intravitreal bevacizumab on as needed regimen, and to analyze baseline risk factors for CNV resolution or recurrence. METHODS: Ninety-one eyes of 80 patients with newly diagnosed wet AMD were retrospectively studied. All eyes were treated with a round of three monthly intravitreal bevacizumab injections, followed by one additional 'bonus' injection after resolution of CNV activity. During follow-up, eyes were monitored with fluorescein angiography, optical coherence tomography, and best-corrected visual acuity (BCVA). In case of recurrences of CNV activity, eyes were retreated with other rounds of bevacizumab injections following the same treatment protocol. RESULTS: Over a median follow-up of 532d, the median resolution time of CNV activity in the first, second, and third treatment round was 98d, 126d, and 111d, respectively. The median recurrence time for the three rounds was 154d, 126d, and 151d, respectively. No significant difference in resolution time (P=0.09) or in recurrence time (P=0.11) was detected among treatment rounds. Age (P=0.0082) and lens status (P=0.035) were found to be associated with CNV resolution; for every 1-year increase in age there was 4% greater chance of CNV resolution; Phakic eyes demonstrated a 33% better chance to experience CNV resolution than pseudophakic eyes. For CNV recurrence, lens status (P=0.0009) and gender (P=0.0446) were found to be predictive; pseudophakic eyes had a 3.69-fold greater risk to experience recurrence of CNV activity compared to phakic eyes; males had a 2.19-fold greater risk to experience recurrence of CNV activity than females. No significant BCVA changes among three treatment rounds were noted (P=0.56). CONCLUSION: Resolution time and recurrence time of CNV activity were not significantly different among treatment rounds, suggesting absence of tachyphylaxis to bevacizumab. A cautious decision should be made upon discontinuing treatment in wet AMD eyes of younger or pseudophakic patients, which showed slower response to bevacizumab. In addition, wet AMD eyes of male or pseudophakic patients should be evaluated more carefully after stopping the treatment, because they may have early reactivation of the CNV. BCVA was preserved by bevacizumab treatment despite multiple recurrences. Copyright International Journal of Ophthalmology Press
Combined depth imaging technique on spectral-domain optical coherence tomography
No full textPurpose: To describe a technique to obtain combined images of vitreoretinal and choroidal structures using spectral-domain (SD) optical coherence tomography (OCT) and to evaluate applicability in normal eyes and limitations in eyes with cataract. Design: Prospective, observational case series. Methods: Three different foveal scans, including conventional SD OCT, enhanced depth imaging OCT and the novel method called combined depth imaging (CDI) OCT, were obtained in 42 eyes of healthy volunteers and in 26 eyes with cataract using the Heidelberg Spectralis HRA (Heidelberg Engineering). The CDI OCT images were obtained manually using an image modification process that enhances the vitreoretinal interface first and then the choroid, while averaging 100 separate OCT scans. The visualization of the inner border of the preretinal pocket and the outer border of the choroid was graded by independent masked observers for each OCT scan method. Results: The CDI technique was able to create a good-quality combined image of the posterior structures in all the eyes, including eyes with cataract. The agreement between the grading performed by the independent observers was high for both the inner border of the vitreal pocket (κ, 0.86; P <.001) and the outer choroidal border (κ, 0.90; P <.001). CDI OCT was equivalent to conventional SD OCT in visualizing the vitreal pocket (P =.445 for normal eyes, P =.162 for eyes with cataract) and was equivalent to enhanced depth imaging OCT in visualizing the outer choroidal border (P =.660 for normal eyes, P =.329 for eyes with cataract). CDI OCT was superior to conventional SD OCT and enhanced depth imaging OCT in visualizing both of the structures (P <.001). Conclusions: The manual technique of CDI OCT is highly sensitive to visualize posterior vitreoretinal and choroidal structures into a single full-depth image and is not affected by mild to moderate cataract
Correlation of spectral domain optical coherence tomography characteristics with visual acuity in eyes with subfoveal scarring after treatment for wet age-related macular degeneration
No full textPURPOSE:: Correlating spectral domain optical coherence tomography characteristics with final best-corrected visual acuity (BCVA) in eyes with subfoveal scarring after treatment for wet age-related macular degeneration. METHODS:: Seventy-nine eyes from 64 subjects, who developed subfoveal scarring after treatment of wet age-related macular degeneration, were retrospectively studied. Spectral domain optical coherence tomography characteristics were analyzed, including percentage disruption of inner segment/outer segment junction and external limiting membrane, central macular thickness, subfoveal scar thickness, subretinal scar area, and proximity of retina with intact outer structures to the fovea. A multivariate stepwise regression analysis was performed with the final BCVA logarithm of minimum angle of resolution as a response and the above-identified spectral domain optical coherence tomography variables as predictors. RESULTS:: There was no correlation between the final BCVA and any of the demographic data, treatment modality received, and central macular thickness. The final BCVA was significantly correlated with the percentage of inner segment/outer segment disruption (P = 0.011), external limiting membrane disruption (P = 0.005), and scar area on spectral domain optical coherence tomography (P = 0.018). Multivariate analysis showed that the baseline BCVA and distance between the fovea and nearest retina with intact outer structures are the most predictive of the final BCVA (R = 0.52). CONCLUSION:: Baseline BCVA and integrity of outer retinal structures are good predictors of the final BCVA of wet age-related macular degeneration patients developing scarring after treatment
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Influence of scanning density on macular choroidal volume measurement using spectral-domain optical coherence tomography
No full textBackground To evaluate the impact of scanning density on macular choroidal volume measurement using spectraldomain optical coherence tomography (SD-OCT). Methods Thirty eyes of normal subjects underwent consecutive raster choroidal scanning protocols using SD-OCT in enhanced-depth imaging mode. Manual choroidal segmentation was performed using the built-in automated retinal segmentation software to obtain five analyses with different interscan distances, including inter-scan distances of 30 μm, 60 μm, 120 μm, 240 μm, and 480 μm. The built-in software of the device automatically generated the choroidal thickness and volume map in the similar manner as for the retinal volume map, using the standardized Early Treatment Diabetic Retinopathy Study (ETDRS) grid. For each raster scan, mean absolute difference and relative difference of mean foveal choroidal thickness (FCT), foveal choroidal volume (FCV) and total macular choroidal volume (TCV) in comparison to "true value" (i.e., 30-μm inter-scan distance) were calculated. Results The maximum relative differences were 10 % and 16 % for TCV and FCV respectively. For mean FCT, the maximum absolute difference was 31 μm, and maximum relative difference was 12.7 %. No statistically significant differences were found in measurements of mean foveal choroidal thickness (p=0.912) and volume (p=0.944), as well as macular choroidal volume (p=0.912), with varying inter-scan distance. Conclusions Our study shows that approximately 16 scans over the macula with a inter-scan distance of 480 μm is sufficient to provide a clinically relevant and reliable choroidal thickness/volume map. This information could be useful in the design of choroidal scanning protocols for future clinical trials
Repeatability and reproducibility of manual choroidal volume measurements using enhanced depth imaging optical coherence tomography
No full textTo evaluate the repeatability and reproducibility of manual choroidal volume (CV) measurements by spectral domain- optical coherence tomography (SD-OCT) using enhanced depth imaging (EDI). Sixty eyes of 32 patients with or without any ocular chorioretinal diseases were enrolled prospectively. Thirty-one choroidal scans were performed on each eye, centered at the fovea, using a raster protocol. Two masked observers demarcated choroidal boundaries by using built-in automated retinal segmentation software on two separate sessions. Observers were masked to each other's and their own previous readings. A standardized grid centered on the fovea was positioned automatically by OCT software, and values for average CVs and total CVs in three concentric rings were noted. The agreement between the intraobserver measurements or interobserver measurements was assessed using the concordance correlation coefficient (CCC). Bland-Altman plots were used to assess the clinically relevant magnitude of differences between inter- and intraobserver measurements. The interobserver CCC for the overall average CV was very high, 0.9956 (95% confidence interval [CI], 0.991-0.9968). CCCs for all three Early Treatment Diabetic Retinopathy Study concentric rings between two graders was 0.98 to 0.99 (95% CI, 0.97-0.98). Similarly intraobserver repeatability of two graders also ranged from 0.98 to 0.99. The interobserver coefficient of reproducibility was approximately 0.42 (95% CI, 0.34-0.5 mm(3)) for the average CV. CV measurement by manual segmentation using built-in automated retinal segmentation software on EDI-SD-OCT is highly reproducible and repeatable and has a very small range of variability
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