PubMed · 10374150
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1999. Consultation section. Cataract surgical problem.. https://pubmed.ncbi.nlm.nih.gov/10374150/
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BACKGROUND AND OBJECTIVE: To evaluate the potentials of a 1310-nm optical coherence tomography (OCT) system to penetrate the highly backscattering sclera in enucleated human eyes and provide visualization of intraocular structures by transscleral imaging. STUDY DESIGN/MATERIALS AND METHODS: OCT-images were generated by an experimental prototype (Medical Laser Center, Lübeck, Germany) using a superluminescence diode with a wavelength of 1310 nm. OCT-images were taken from two enucleated human eyes using 100-200 axial scans with 60 Hz line scan frequency and compared to subsequent histologic sections. RESULTS: Transscleral OCT allowed penetration of the sclera and the anterior chamber angle could be completely identified. Some change within the anterior eye segment could be demonstrated with high accuracy. Additionally, limited demonstration of the ciliary body region was achieved. Due to limited signal intensity no detailed imaging of the pars plana and pars plicata region was possible. However, more posterior measurements allowed transscleral visualization of a retinal detachment. CONCLUSIONS: OCT using lightsources with a wavelength longer than that used in conventional OCT provides a promising imaging technique at high resolution allowing transscleral imaging of the anterior eye segment.
BACKGROUND: Information about changes in the trabeculectomy ostium and adjacent structures related to flattening of the anterior chamber in the early postoperative period may be important for management. We assessed the ostium and adjacent structures by means of ultrasound biomicroscopy (UBM) in order to identify common patterns related to postoperative flattening of the anterior chamber. METHODS: We studied 15 eyes of 15 consecutive patients. A first UBM examination was performed when the patient was referred. Changes in the ostium (evidence of tissue adhesions to the ostium) were evaluated with UBM after the chamber flattening resolved, at least 60 days after the first examination. The following features were noted: depth of the anterior chamber, size and patency of the ostium, rotation of ciliary processes, presence of uveal effusion and ultrasound functioning of the bleb. RESULTS: All the patients had ring-shaped ciliochoroidal effusions; in nine eyes the effusions were found only with UBM. In four eyes an anterior-posterior deformation of the ostium was found. Synechiae in the ostium were identified in the three eyes in which iris remnants had been recognized at the site on the initial UBM examination. INTERPRETATION: Our observations confirm the presumed pathophysiology of flat anterior chamber without bleb leak. Ring-shaped effusions were detected on UBM even in cases in which conventional ultrasonography showed no positive results. UBM is a helpful tool in the diagnosis and management of flattening of the anterior chamber after trabeculectomy.
PURPOSE: To evaluate methods of measuring anterior chamber depth (ACD) before and after cataract surgery. SETTING: St. Erik's Eye Hospital, Stockholm, Sweden. METHODS: A-scan (BVI Axis) and Scheimpflug imaging (Nidek EAS-1000) were used to measure ACD preoperatively and 6 and 18 weeks after phacoemulsification with implantation of a poly(methyl methacrylate) (PMMA) intraocular lens (IOL) in 23 patients. Because of a large systematic difference between the 2 methods, measurement with Orbscan (Orbtek) and optical pachymetry (Haag-Streit) were included when measurements were repeated 36 weeks postoperatively. A t test for paired observations was used for statistical analysis. RESULTS: Preoperatively, the mean A-scan measurements were significantly shorter than the Scheimpflug values: 3.05 mm +/- 0.36 (SD) and 3.37 +/- 0.35 mm, respectively (P < .001). At 6 weeks, the difference was more pronounced: 3.73 +/- 0.26 mm and 4.65 +/- 0.33 mm, respectively (P < .001). At 36 weeks, the A-scan and Scheimpflug values remained unchanged. The results of the Scheimpflug measurements were confirmed with optical pachymetry and Orbscan analysis. CONCLUSIONS: There was good agreement between results obtained with 3 methods based on optical principles. Considering the basic and simple measurement principle of these instruments, they appear to provide the correct result. The A-scan equipment used in this study is unsuitable for determination of ACD in eyes with PMMA IOLs.