Stefan Hagen

Spectral-Domain Optical Coherence Tomography for Monitoring Epiretinal Membrane Surgery

PURPOSE To assess prognostic factors in epiretinal membrane (ERM) surgery using spectral-domain (SD) optical coherence tomography (OCT). DESIGN Prospective, interventional case series. PARTICIPANTS Forty-one patients. METHODS Patients with a diagnosis of ERM were examined with spectral-domain and time-domain (TD) OCT before and after surgery. MAIN OUTCOME MEASURES Main outcome measures were functional results and predefined OCT patterns. Cofactors analyzed were the type of ERM, the duration and grading of subjective metamorphopsia, simultaneous cataract surgery, the type of dyes used, the duration of surgery, gender, and age. A multivariate regression analysis was performed. RESULTS Thirty-nine patients (95%) showed an improved or stable best-corrected distance visual acuity (DVA) at 3 months, whereas 36 patients (88%) showed an improved or stable best-corrected near visual acuity (NVA) at 3 months. Significant correlations (P>0.4) were found between the course of central retinal thickness (CRT) assessed using SD OCT and TD OCT (P<0.02). No clinically relevant correlations (P<0.3) were seen between CRT and VA (P>0.1). Baseline DVA and NVA were found to be significant prognostic values for the postoperative decrease in CRT in both OCT systems (P<0.04) as well as for the visual outcomes (P<0.007) at 3 months. In addition, the integrity of the junction between the photoreceptor inner segment and outer segment (IS/OS) significantly influenced the visual outcomes at 3 months (P<0.038). The baseline profile of the internal limiting membrane (ILM) significantly influenced the NVA at 3 months (P<0.009), whereas the postoperative foveal contour significantly influenced the DVA at 3 months (P<0.025). The type of ERM, subjective metamorphopsia, simultaneous cataract surgery, the type of dyes used, the duration of surgery, gender, or age had no significant influence on patient outcome (P>0.05). Compared with TD OCT, SD OCT allowed for a more precise differentiation between the ERM and the retinal surface and for a better evaluation of the IS/OS line. CONCLUSIONS Besides the baseline VA, the integrity of the IS/OS line, better visualized by SD OCT, can be used to predict the functional outcomes after surgery. Additionally, analyzing the ILM profile and the foveal contour may help to understand limited visual outcomes after surgery. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Non-responders to treatment with antagonists of vascular endothelial growth factor in age-related macular degeneration

Purpose Most of the publications on modern therapy of neovascular age-related macular degeneration focus on the effect of the treatment. The purpose of this study is to determine the frequency of non-responders to anti-vascular endothelial growth factor (anti-VEGF) treatment and find possible reasons for their failure to respond. Methods The records of patients treated until the end of 2008 the first time with either bevacizumab or ranibizumab were reviewed. Based on the availability of measurable results and according to prior publications showing the effect of the therapy, loss of three lines of distance acuity, increase of retinal thickness or lesion size were identified as indicators of non-responders. Two of these three signs had to be present. Results 334 eyes of 283 patients were included; 74.55% received bevacizumab and 25.45% received ranibizumab. Overall 14.37% of the eyes were identified as non-responders (14.06% in the bevacizumab group and 15.29% in the ranibizumab group). Baseline distance acuity and vitreo-retinal adhesions were significantly correlated with non-responders. Correlations with age, gender, lesion type, other morphologic features, and the kind of anti-VEGF agent failed to be significant. 10.4% of the non-responders showed a delayed but good response to anti-VEGF treatment. Conclusions About 15% did not sufficiently respond to anti-VEGF treatment. Vitreo-retinal adherences were the only ophthalmologic factor which could be identified to be significantly correlated with insufficient response.

Repeatability and Reproducibility of Retinal Thickness Measurements by Optical Coherence Tomography in Age-Related Macular Degeneration

PURPOSE To evaluate the repeatability and reproducibility of retinal thickness measurements in exudative age-related macular degeneration (AMD) using Stratus optical coherence tomography (OCT) (Carl Zeiss Meditec, Inc., Dublin, CA). DESIGN Prospective, observational case series. PARTICIPANTS A total of 200 eyes of 200 subjects with exudative AMD. METHODS Macular thickness and fast macular thickness programs of Stratus OCT were performed twice by the same examiners or 2 different examiners. The sequence of examiners was randomized 1:1:1:1. The variability of 1-mm subfield central retinal thickness (CRT), center point thickness (CPT), and retinal volume (RV) was calculated. MAIN OUTCOME MEASURES Interobserver and intraobserver variability of retinal thickness measurements. RESULTS Ninety-nine patients/eyes were enrolled in study arm 1 (repeated by the same examiner), and 101 patients/eyes were enrolled in study arm 2 (repeated by different examiners). Values of CPT, CRT, and RV were well correlated (interclass correlation coefficient, 0.71-0.93) in both study arms, revealing better results for the macular thickness program than for the fast macular thickness program. Threshold algorithm line failures were significantly correlated to the absolute differences of 2 repeated measurements for CPT, CRT, and RV but not with manually corrected maximum retinal thickness (MRT). Maximum retinal thickness was significantly influenced by the examiner performing the measurement. Age, lesion composition, examiner performing OCT examination, and sequence of examination had no significant influence. CONCLUSIONS The repeatability and reproducibility of retinal thickness measurements were high, presenting better results for CRT and RV versus CPT, and for the macular thickness program versus the fast macular thickness program. The reliability of retinal thickness measurement was most frequently affected by algorithm line failures and fixation problems. A possible solution may be manually corrected measurement, such as MRT.

Quality of the threshold algorithm in age-related macular degeneration: Stratus versus Cirrus OCT.

PURPOSE Automatically generated measurements of the retinal volume or the central retinal thickness are based on correctly set threshold lines on the retinal surface and the retinal pigment epithelium. The purpose of this study was to compare the accuracy of threshold algorithm lines of Stratus optical coherence tomography (OCT) with those of Cirrus OCT. METHODS A consecutive series of patients at least 50 years of age with exudative age-related macular degeneration was included. Stratus OCT (retinal thickness program) and Cirrus OCT (macular cube 512 x 128) were performed by the same examiner, the sequence of the examinations was randomized. Two independent examiners evaluated the positioning of the threshold algorithm lines and performed a grading of the failures. Logistic regression analysis was applied for evaluation of the failure rate. RESULTS One hundred four patients were included. For the entire OCT examination (6 scans Stratus OCT, 128 scans Cirrus OCT) algorithm line failures were detected in 69.2% of the Stratus OCT and in 25% of the Cirrus OCT examinations, with the difference reaching statistical significance (P < 0.001). The median failure grade was 1 (0-6) for Stratus and 0 (0-5.15) for Cirrus OCT. Age, measurement sequence, and investigator did not influence the error rates. CONCLUSIONS With Cirrus OCT automatically performed and therefore objective measurements of central retinal thickness and retinal volume were provided correctly in 69.2% of the scans. Furthermore, this latest software version offers the possibility of manual correction of false positioned algorithm lines (ClinicalTrials.gov number, NCT00568191).

Half-fluence photodynamic therapy in chronic central serous chorioretinopathy.

Purpose: To evaluate the results of indocyanine green angiography (ICGA)-guided verteporfin (Visudyne®; Novartis Pharma, Switzerland) photodynamic therapy (PDT) with half-fluence rate in the treatment of chronic central serous chorioretinopathy. Methods: A retrospective review was conducted of 20 eyes of 19 consecutive patients with subfoveal fluid cause by chronic central serous chorioretinopathy with choroidal hyperpermeability on ICGA and symptoms of at least 6 months. ICGA-guided verteporfin (6 mg/m2) PDT with half-fluence rate (25 J/cm2) was performed. ICGA findings were classified as intense, intermediate, or minimal hyperfluorescence depending on the degree of choroidal hyperpermeability. The resolution of the subretinal fluid and recurrence rates were assessed in relation to the different degrees of choroidal hyperfluorescence. Results: Best-corrected visual acuity at baseline was 40 letters (±13; n = 20) according to the Early Treatment Diabetic Retinopathy Study chart. At 12 months after PDT, the mean best-corrected visual acuity improved to 44 letters (P < 0.01). Pretreatment central foveal thickness 325 &mgr;m and decreased by a mean of 103 &mgr;m at Month 12 control (P < 0.05). At Month 1 after PDT, subretinal fluid in spectral-domain optical coherence tomography was completely resolved in 100% of eyes regardless to their degree of choroidal hyperfluorescence. Two eyes of the intense hyperfluorescence group and 1 eye of the intermediate hyperfluorescence group developed recurrence of symptoms over 12 months and received another PDT with half-fluence rate within the 12-month control period. Treatment effect was not depending on the degree of choroidal hyperpermeability at baseline. No systemic side effects were observed during the 12-month follow-up. Conclusion: ICGA-guided half-fluence PDT with verteporfin is effective in treating chronic symptomatic central serous chorioretinopathy with choroidal hyperpermeability in ICGA, resulting in both visual improvement and reduction of central foveal thickness.

Comparison of visual performance with blue light–filtering and ultraviolet light–filtering intraocular lenses

PURPOSE: To compare the contrast sensitivity, glare, color perception, and visual acuity at different light intensities with yellow‐tinted and clear intraocular lenses (IOLs) by different manufacturers. SETTING: Ludwig Boltzmann Institute of Retinology and Biomicroscopic Laser‐Surgery, Department of Ophthalmology, Rudolf Foundation Clinic, Vienna, Austria. DESIGN: Comparative case series. METHODS: Eyes were randomized to 1 of the following IOLs: AF‐1 (UY) (yellow tinted), AcrySof SN60AT (yellow tinted), AF‐1 (UV) (clear), or AcrySof SA60AT (clear). One week and 2 months postoperatively, monocular contrast sensitivity function and color discrimination were tested and the corrected distance and near visual acuities were evaluated. All tests were performed under different light intensities (10 to 1000 lux). RESULTS: Of the 80 patients enrolled, 76 completed the study; there were 37 eyes in the yellow‐tinted IOL group and 39 in the clear IOL group. There were no significant differences between yellow‐tinted IOLs and clear IOLs except in color vision under mesopic conditions (10 lux). Patients with a yellow‐tinted IOL made significantly more mistakes in the blue‐light spectrum than patients with clear IOLs (P = .00015). There was no significant difference under photopic conditions (1000 lux). CONCLUSIONS: The yellow‐tinted IOLs were equivalent to the clear IOLs in postoperative contrast sensitivity, visual acuity, and color perception under photopic conditions. Patients with yellow‐tinted IOLs made statistically significantly more mistakes in the blue range under dim light than patients with clear IOLs. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Conversion of Stratus optical coherence tomography (OCT) retinal thickness to Cirrus OCT values in age-related macular degeneration

Aim Spectral domain optical coherence tomography (SD OCT) is of increasing importance and is gradually replacing time domain OCT (TD OCT). Our aim was to determine a formula to convert Stratus OCT (TD OCT) to Cirrus OCT (SD OCT) retinal thickness. Methods Central retinal thickness (CRT) and retinal volume (RV) were obtained by the macular thickness program of Stratus OCT and the cube 512×128 program of Cirrus OCT in patients with exudative age-related macular degeneration (AMD). Algorithm line failures were corrected. A linear model with Stratus OCT CRT as fixed factor and Cirrus OCT CRT as dependent variable was applied to calculate the conversion formula. Results OCT examinations of 104 eyes of 104 patients were reviewed and corrected when necessary. Stratus and Cirrus OCT CRT were significantly correlated (p<0.0001). For CRT the formula Cirrus CRT=58.63+0.94× Stratus CRT was calculated. The correlation was significantly influenced by the height of the CRT values (p<0.0001), but not by whether correction was necessary. For RV the formula Cirrus OCT RV=3.098+0.98× Stratus OCT RV was calculated. Conclusion Stratus OCT and Cirrus OCT use a different posterior reference line within the hyper-reflective band of the outer retina. Therefore a conversion formula is necessary to compare Stratus and Cirrus OCT CRT values, and this has been determined in our study.

Reproducibility and comparison of retinal thickness and volume measurements in normal eyes determined with two different Cirrus OCT scanning protocols.

Purpose: To assess reproducibility and compare raster scanning protocols of Cirrus high-definition optical coherence tomography (Carl Zeiss Meditec, Dublin, CA). Methods: Five hundred and twenty-eight computed tomography scans were performed in 17 healthy subjects. Four sessions were performed at each visit including two 200 × 200 and two 512 × 128 macular cube scans per session. The examined eye, observer, and order of scanning protocols in-between each session were randomly chosen. Reproducibility was described with intraclass correlation coefficients, coefficients of variance, intervisit, interrater, intersession intra-, and intersubject standard deviations. Results: Intraclass correlation coefficients ranged from 80.4% to 97.8% and the coefficients of variance from 0.7% to 2.3% for retinal volume and retinal thickness measurements. Intersubject, intervisit, interrater, intersession, and intrasubject standard deviations ranged from 0 μm to 18.54 μm. Differences in retinal thickness between protocols were small (range 3.55 ± 1.95 μm to 0.81 ± 0.59 μm) but significant for the central (P < 0.0001), the outer superior (P = 0.0036), temporal (P = 0.0026), and nasal subfield (P < 0.0001). Average difference of retinal volume between protocols was 0.05 ± 0.04 mm3 (P = 0.0001). Conclusion: Both raster scanning protocols of the Cirrus optical coherence tomography showed excellent reproducibility of retinal thickness and volume measures. Significant differences between protocols for retinal thickness in four macula thickness map subfields and for retinal volume were found.

Advantages of using a ray-traced, three-dimensional rendering system for spectral domain Cirrus HD-OCT to visualize subtle structures of the vitreoretinal interface.

BACKGROUND AND OBJECTIVE To create a ray-traced, three-dimensional display system for Cirrus high-definition optical coherence tomography (Carl Zeiss Meditec, Inc., Dublin, CA) that improves the visualization of subtle structures of the vitreoretinal interface. PATIENTS AND METHODS High-definition optical coherence tomography (HD-OCT) data for epiretinal membranes (17 eyes), macular holes (11 eyes), and posterior vitreal detachments (17 eyes) were collected. A display system that visualizes the acquired data using ray-tracing algorithms was designed and compared with the Cirrus HD-OCT 2.0 advanced visualization software system. The area around the vitreoretinal interface was visualized using a 100-microm-thick internal limiting membrane (ILM) fitted slab as well as ILM and retinal pigment epithelium surface reconstructions. RESULTS Subtle structures could be visualized more distinctly using the ray-traced, three-dimensional rendering software. CONCLUSION A ray-traced visualization system improves the visualization of subtle structures in and around the vitreoretinal interface.

Repeated measures of macular pigment optical density to test reproducibility of heterochromatic flicker photometry

Purpose:  To report the reproducibility of macular pigment optical density (MPOD) values assessed with heterochromatic flicker photometry (HFP) in healthy individuals.