Agreement between a new swept-source ocular coherence tomography and a Placido disc-dual Scheimpflug ocular biometric devices.

PURPOSE: To evaluate the agreement between two biometry devices, the Heidelberg Anterion and the Galilei G6 Lens Professional. METHODS: Eyes were scanned with both biometry devices. Analysis of inter-device agreement was conducted for the following metrics: flat (K1), steep (K2) and mean K (Km) for anterior, posterior and total cornea, lens thickness (LT), central corneal thickness (CCT), anterior chamber depth (ACD), white to white (WTW) and axial length (AL). Generalised Estimating Equations were used to account for inter-eye correlation. Bland-Altman analysis was conducted to derive the mean difference (MD) and limits of agreement (LoA) between devices. Differences were deemed clinically significant if they would result in a change in post-operative refraction of 0.25D or more. RESULTS: 159 eyes of 91 patients were included. For the anterior cornea, no significant MD was found for K1 (-0.11D) and K2 (-0.10D), although a significant MD was found for Km (-0.10D). For posterior cornea, while there were no significant MDs between devices, the LoAs were wide for both posterior K1(-0.70, 0.68) and posterior K2 (-1.01, 1.29). For total corneal power, significant MDs were found in K1 (0.36D), and Km (0.26D) but not for K2 (0.17D). Significant MDs were found for LT (0.179mm), CCT (-0.005mm), ACD (-0.111mm) and WTW (-0.158mm), but not for AL (-0.021mm, p > 0.05).Conclusion: There are statistically but not clinically significant differences between Anterion and Galilei G6 Lens Professional in anterior Km, LT, CCT, ACD and WTW. Measurements of the posterior and total cornea are not interchangeable between devices.

Agreement between 2 SS-OCT biometry devices.

PURPOSE: To assess the agreement between 2 swept-source optical coherence tomography biometry devices, Anterion and IOLMaster 700. SETTING: Tertiary referral center, Brisbane, Australia. DESIGN: Prospective comparative study. METHODS: Bland-Altman analysis was used to assess agreement between devices for flat (K1), steep (K2), and mean (Km) keratometry for anterior, posterior, and total cornea, lens thickness (LT), anterior chamber depth (ACD), central corneal thickness (CCT), white to white (WTW), and axial length (AL). Generalized estimating equations were used to control for within-patient between-eye correlations. Interdevice differences were considered clinically significant if they were likely to alter the spherical refractive outcome by 0.25 diopter (D) or more. RESULTS: 159 eyes of 91 patients (41 male, 50 female) were included. Statistically significant differences were found for K1, K2, and Km for anterior, posterior, and total cornea. When the Anterion was compared with the IOLMaster 700, the mean differences were as follows: anterior K1: -0.17 D, anterior K2: -0.18 D, anterior Km: -0.17 D, posterior K1: -0.38 D, posterior K2: -0.36 D, posterior Km: -0.37 D, total K1: -0.65 D, total K2: -0.82 D, and total Km: -0.74 D. The difference in posterior and total K metrics was clinically significant. Statistically significant differences were noted for LT: 0.159 mm, CCT: -0.004 mm, ACD: 0.054 mm, and WTW: -0.152 mm, although these were not found to be clinically significant. There was no significant difference between devices for AL. CONCLUSIONS: This study found statistically and clinically significant differences for both posterior and total keratometry between the Anterion and the IOLMaster 700. Posterior and total corneal parameters cannot be considered interchangeable between devices.

Clinicopathologic Examination of Translucent Refractile Intraluminal Tissue Coagulum From the Proximal Tube of a Baerveldt Glaucoma Drainage Device.

PURPOSE: To describe an unusual case of glaucoma drainage tube blockage. PATIENTS: A 76-year-old woman presented with left endothelial graft failure. Her previous ocular history included primary open-angle glaucoma diagnosed for 15 years and Fuch's endothelial dystrophy. Three years before presentation, the left eye required a Descemet stripping endothelial keratoplasty followed by a trabeculectomy with mitomycin C and subsequent Baerveldt tube insertion 3 years previously. Intraocular pressures were right 9 and left 19 mm Hg. The endothelial graft demonstrated supra-temporal edema, in proximity to the sulcus placed tube tip. METHODS: A repeat endothelial keratoplasty was undertaken. During surgery, an attempt to flush the tube ab internally with balanced salt solution on a 27-G Rycroft cannula, resulted in extrusion of a long translucent tubular plug from within the silicone tube into the anterior chamber. This was removed with intraocular forceps and sent for histopathology. The endothelial keratoplasty was performed and an air bubble placed in the anterior chamber. RESULTS: The histopathology was reported as fibrinohemorrhagic material associated with refractile material, detected under polarized light microscopy. At 6 months follow-up, the graft was clearing well, the tube in situ and the intraocular pressure 6 mm Hg. CONCLUSIONS: One possible cause of the refractile material within the specimen is spalled particles of silicone, presumably from the tube. This finding potentially questions the long-term stability of silicone products in the eye and may be a cause of capsular fibrosis around the glaucoma drainage device plate.