Christiane I. Falkner-Radler

Three-dimensional optical coherence tomography at 1050 nm versus 800 nm in retinal pathologies: enhanced performance and choroidal penetration in cataract patients.

Frequency domain optical coherence tomography (FD-OCT), based on an all-reflective high-speed InGaAs spectrometer, operating in the 1050 nm wavelength region for retinal diagnostics, enables high-speed, volumetric imaging of retinal pathologies with greater penetration into choroidal tissue is compared to conventional 800 nm three-dimensional (3-D) ophthalmic FD-OCT systems. Furthermore, the lower scattering at this wavelength significantly improves imaging performance in cataract patients, thereby widening the clinical applicability of ophthalmic OCT. The clinical performance of two spectrometer-based ophthalmic 3-D OCT systems compared in respect to their clinical performance, one operating at 800 nm with 150 nm bandwidth (approximately 3 microm effective axial resolution) and the other at 1050 nm with 70 nm bandwidth (approximately 7 microm effective axial resolution). Results achieved with 3-D OCT at 1050 nm reveal, for the first time, decisive improvements in image quality for patients with retinal pathologies and clinically significant cataract.

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.

Feasibility of intrasurgical spectral-domain optical coherence tomography.

Purpose: To evaluate the feasibility of intrasurgical spectral-domain optical coherence tomography in a pilot study. Methods: Using a Carl Zeiss Meditec Cirrus HD-OCT system adapted to the optical pathway of a Zeiss OPMI VISU 200 surgical microscope, 512 × 128 macular cube scans were performed during various steps of microsurgical procedures in 25 cases. The acquired volume data were postprocessed and visualized using a ray-traced three-dimensional display system. Results: The surgical procedures included pars plana vitrectomies for epiretinal membranes (n = 8), macular holes (n = 4), primary rhegmatogenous retinal detachment (n = 1), proliferative diabetic retinopathy (n = 3), silicone oil removal (n = 2), and cataract surgery only (n = 7). It was possible to acquire intraretinal scans with sufficient quality from all patients. Decisions for additional membrane peeling, knowledge about the behavior of the macular hole and the foveal depression during and after membrane removal, information about clinically invisible fluid accumulation under silicone oil or in a clinically diagnosed “macula-on” retinal detachment, and the condition of the fovea immediately after cataract removal could be gained. Conclusion: Intrasurgical spectral-domain optical coherence tomography evaluation is feasible using the tested system and may positively influence surgical decisions and techniques resulting in an improved patient outcome.

Trends in primary retinal detachment surgery: Results of a bicenter study

Purpose: To assess trends and outcomes in retinal detachment (RD) surgery based on a retrospective, interventional, bicenter study. Methods: Baseline demographic data, surgical procedures, and outcomes from 230 patients with a diagnosis of primary rhegmatogenous RD, who underwent surgery between January 2007 and December 2008 at the Rudolf Foundation Clinic, Vienna (Center 1) and the Weill Cornell Medical College, New York, (Center 2) were analyzed using a regression model. Results: Besides the baseline parameters, lens status (P = 0.01), refraction (P = 0.01), retinal tears (P < 0.02), proliferative vitreoretinopathy (P = 0.02), and previous treatment (P < 0.02), the primary RD procedure (P < 0.0001) was significantly different between the 2 centers. In Center 1, scleral buckling was the most common primary RD procedure (66.19%) compared with vitrectomy (82.42%) in Center 2. Primary retinal reattachment (88.49% Center 1 vs. 84.62% Center 2, P = 0.43) and best-corrected visual acuity at the final follow-up (best-corrected visual acuity ≥ 0.3 logarithm of minimum angle of resolution 48.92% Center 1 vs. 47.25% Center 2, P = 0.78) were not significantly different between the 2 centers. Conclusion: Although there is a trend toward primary vitrectomy, scleral buckling was preferred in the center in Vienna and primary vitrectomy in the center in New York. Despite the different primary RD procedures, anatomical and visual outcomes were comparable.

Accuracy of preoperative biometry in vitrectomy combined with cataract surgery for patients with epiretinal membranes and macular holes: results of a prospective controlled clinical trial.

PURPOSE: To evaluate how adding vitrectomy to cataract surgery affects the accuracy of preoperative biometry and postoperative refractive outcomes. SETTING: Department of Ophthalmology, Ludwig Boltzmann Institute of Retinology and Biomicroscopic Lasersurgery, Rudolf Foundation Clinic, Vienna, Austria. METHODS: This study comprised 40 patients with vitreoretinal pathology and coexisting significant cataract (study group) and 40 patients with significant cataract only (control group). The main outcome measure was intraocular lens (IOL) power prediction error. Secondary outcome measures were spherical equivalent, anterior chamber depth, axial length, keratometry values, and intraocular pressure. A multivariate regression analysis was performed. RESULTS: There was a significant difference in prediction error between the study group and control group (P<.05). The addition of vitrectomy was associated with induced myopia of approximately −0.4 diopter, more so in patients who had epiretinal membrane removal than in patients with macular hole surgery (P = .04). There was no significant difference in prediction error between the 3 IOLs used (P = .2). CONCLUSION: The myopic shift was strongly dependent on the diagnosis and the need for intraocular tamponade, indicating that a slightly hyperopic IOL should be used in patients having combined surgery.

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).

INTRASURGICAL MICROSCOPE-INTEGRATED SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY-ASSISTED MEMBRANE PEELING.

Purpose: To evaluate microscope-integrated intrasurgical spectral domain optical coherence tomography during macular surgery in a prospective monocenter study. Methods: Before pars plana vitrectomy and before, during, and after membrane peeling, 512 × 128 macular cube scans were performed using a Carl Zeiss Meditec Cirrus high-definition OCT system adapted to the optical pathway of a Zeiss OPMI VISU 200 surgical microscope and compared with retinal staining. Results: The study included 51 patients with epiretinal membranes, with 8 of those having additional lamellar macular holes, 11 patients with vitreomacular traction, and 8 patients with full-thickness macular holes. Intraoperative spectral domain optical coherence tomography allowed performing membrane peeling without using retinal dyes in 40% of cases (28 of 70 patients). No residual membranes were found in 94.3% of patients (66 of 70 patients) in intrasurgical spectral domain optical coherence tomography and subsequent (re)staining. In patients with vitreomacular traction, intrasurgical spectral domain optical coherence tomography scans facilitated decisions on the need for an intraocular tamponade after membrane peeling. Conclusion: Intraoperative spectral domain optical coherence tomography was comparable with retinal dyes in confirming success after membrane peeling. However, the visualization of flat membranes was better after staining.

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.

Vitrectomy combined with endolaser or an encircling scleral buckle in primary retinal detachment surgery: a pilot study.

To compare pars plana vitrectomy and 360° endolaser therapy with pars plana vitrectomy and an encircling scleral buckle for the treatment of primary rhegmatogenous retinal detachments in a randomized pilot study including 60 patients.