Abstract:We analyze the benefits and problems of in vivo optical coherence tomography (OCT) imaging of the human retina at A-scan rates in excess of 1 MHz, using a 1050 nm Fourier-domain mode-locked (FDML) laser. Different scanning strategies enabled by MHz OCT line rates are investigated, and a simple multi-volume data processing approach is presented. In-vivo OCT of the human ocular fundus is performed at different axial scan rates of up to 6.7 MHz. High quality non-mydriatic retinal imaging over an ultra-wide field is achieved by a combination of several key improvements compared to previous setups. For the FDML laser, long coherence lengths and 72 nm wavelength tuning range are achieved using a chirped fiber Bragg grating in a laser cavity at 419.1 kHz fundamental tuning rate. Very large data sets can be acquired with sustained data transfer from the data acquisition card to host computer memory, enabling high-quality averaging of many frames and of multiple aligned data sets. Three imaging modes are investigated: Alignment and averaging of 24 data sets at 1.68 MHz axial line rate, ultra-dense transverse sampling at 3.35 MHz line rate, and dual-beam imaging with two laser spots on the retina at an effective line rate of 6.7 MHz. 58. R. Huber, D. C. Adler, V. J. Srinivasan, and J. G. Fujimoto, "Fourier domain mode locking at 1050 nm for ultrahigh-speed optical coherence tomography of the human retina at 236,000 axial scans per second," Opt. Lett. ©2013 Optical Society of America
Background To evaluate the agreement of intraocular pressure (IOP) and central corneal thickness (CCT) measurements obtained with the non-contact tonometer Corvis Scheimpflug Technology (Corvis ST, OCULUS, Wetzlar, Germany) versus Goldmann applanation tonometry (GAT) and ultrasound-based corneal pachymetry (US-CCT). Methods Eye healthy participants, patients with ocular hypertension (OHT) and patients with open-angle glaucoma were included in this prospective study. In each participant, GAT, US-CCT and measurements with Corvis ST were obtained (Corvis-IOP and Corvis-CCT). Accuracy and repeatability were tested by correlation and regression analyses, Bland-Altman plots and assessment of intraclass correlation coefficients. Results A consecutive series of 188 right study eyes of 188 participants (142 eyes with glaucoma, 10 eyes with OHT and 36 control eyes) were included in this prospective study. The mean GAT of all included was 14.5±4.8 mm Hg compared with mean Corvis-IOP of 15.4±5.6 mm Hg (Spearman's r=0.75, p<0.0001). Mean US-CCT was 544.56±40.0 mm compared with Corvis-CCT of 545.2±46.5 mm (Pearson's r=0.78, p<0.0001). Bland-Altman plots of all included eyes as well as subgroup analyses revealed good agreement of the IOP and CCT measurement techniques. High intraclass correlation coefficient values in 17 patients with repeated measurements revealed very good repeatability (0.942 and 0.937 for Corvis-IOP and Corvis-CCT, respectively). Corvis-IOP but not GAT showed a trend of dependence on CCT. Conclusions Obtaining CCT and measuring IOP with the Corvis ST reveals very good repeatability and good accuracy in healthy subjects and patients with OHT and glaucoma when compared with standardised US pachymetry or GAT.
Purpose Evaluation of postoperative artificial iris prosthesis-related complications. Design Retrospective cohort study. Methods Fifty-one consecutive patients underwent pupillary reconstruction using an artificial iris implant made from silicone between 2011 and 2015. Quantity and quality of complications were subclassified into three groups including mild, moderate, and severe complications. Their management and the learning curve were evaluated. Results In total, 13 (25.5%) of 51 included artificial iris implantations showed unexpected events in various degrees: mild complications: recurrent bleeding (n=1, 2.0%), slight but stable iris deviation (n=1, 2.0%), capsular fibrosis (n=2, 3.9%); moderate complications: suture cutting through the residual iris (n=1, 2.0%), glaucoma (n=3, 5.9%), and corneal decompensation (n=3, 5.9%); severe complications: artificial iris suture loosening (n=2, 3.9%) and dislocation (n=3, 5.9%), synechiae (n=2, 3.9%), glaucoma (n=2, 3.9%), and corneal decompensation (n=5, 9.8%) with the need for surgery, cystoid macular edema (n=3, 5.9%) and retinal detachment (n=1, 2.0%). The complication rate decreased from 83.3% (5 of 6 implantations) in the first year to 13.3% (2 of 15 implantations) in the 4th year. Nineteen of 45 evaluated patients showed a significant gain in best-corrected visual acuity (BCVA) from 1.09 ± 0.56 logMAR to 0.54 ± 0.48 logMAR (p < 0.001), and 13 of 45 eyes had a significant BCVA loss from 0.48 ± 0.39 logMAR to 0.93 ± 0.41 logMAR after surgery (p < 0.001). Conclusions The artificial iris is a feasible option in the treatment of iris defects with a wide spectrum of postoperative complications. The significant reduction of complications after twelve implantations implicates that the procedure is not to be recommended in low volume settings.
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