High-frequency ultrasound measurements of the normal ciliary body and iris.

BACKGROUND AND OBJECTIVE: To determine the normal ultrasonographic thickness of the iris and ciliary body. PATIENTS AND METHODS: This prospective 35-MHz ultrasonographic study included 80 normal eyes of 40 healthy volunteers. The images were obtained at the 12-, 3-, 6-, and 9-o'clock radial meridians, measured at three locations along the radial length of the iris and at the thickest section of the ciliary body. Mixed model was used to estimate eye site-adjusted means and standard errors and to test the statistical difference of adjusted results. Parameters included mean thickness, standard deviation, and range. RESULTS: Mean thicknesses at the iris root, midway along the radial length of the iris, and at the juxtapupillary margin were 0.4 ± 0.1, 0.5 ± 0.1, and 0.6 ± 0.1 mm, respectively. Those of the ciliary body, ciliary processes, and ciliary body + ciliary processes were 0.7 ± 0.1, 0.6 ± 0.1, and 1.3 ± 0.2 mm, respectively. CONCLUSION: This study provides standard, normative thickness data for the iris and ciliary body in healthy adults using ultrasonographic imaging.

Evaluation of the stability of Boston type I keratoprosthesis-donor cornea interface using anterior segment optical coherence tomography.

PURPOSE: To evaluate the anatomic stability of an implanted Boston type I keratoprosthesis (KPro)-donor cornea interface and assess the presence or absence of a potential space (gap) between the KPro front plate and donor cornea using anterior segment optical coherence tomography (AS-OCT). The presence of a gap would raise concerns of a possible pathway for the exchange of extraocular fluid with the anterior chamber. METHODS: Fifteen eyes implanted with a Boston type I KPro were studied by the noncontact technique of AS-OCT (AC Cornea OCT prototype; OTI, Canada). All the KPro devices had been implanted at least 4 weeks before the study (mean: 7 months, range: 1-22 months). Eight eyes had aphakic Kpros, and the other 7 had pseudophakic implants. Anesthetized eyes were imaged before and during pressure application using sterile cotton-tip applicators. Pressure was applied for 10 seconds on the nasal or temporal side of the eye. Images were analyzed for any possible changes in the KPro-donor cornea interface during the application of pressure. RESULTS: Of 15 eyes, 10 had the threaded front plate model with a T-shaped silhouette and corrugated sides, whereas 5 had the threadless type with a T-shaped silhouette and smooth sides on cross-sectional optical coherence tomography. Of the 15 eyes, 2 revealed a gap between the front plate and the surface of the donor cornea. The rest revealed no gaps. With pressure, none of the eyes, including the 2 with gaps, demonstrated any change in the KPro-donor cornea interface during dynamic imaging (eg, gaping or evidence of fluid escape along the KPro-donor cornea borders). In all eyes, the position of the titanium locking ring was visible and verified to be in an adequate position. CONCLUSIONS: The implanted KPro-donor cornea interface seems to be stable dynamically using AS-OCT. A gap that has been documented with this imaging tool showed neither gaping nor escape of anterior chamber fluid during dynamic cross-sectional imaging. Further studies will be needed to assess the cause of these gaps and to determine if they are possibly related to the hydration status of the cornea, suture tension on the donor cornea, or other factors that remain to be determined.

Acquired senile retinoschisis of the peripheral retina imaged by spectral domain optical coherence tomography: a case report.

PURPOSE: We report spectral domain optical coherence tomography findings of the peripheral retina in a patient with senile (acquired) retinoschisis. METHODS: This is an observational case report. Spectral domain optical coherence tomography was performed to image the peripheral retina at the area of retinoschisis in a 70-year-old man with bilateral inferonasal elevated peripheral retinal lesions. Since the lesions were not entirely transparent and smooth, and demonstrated a certain degree of mobility, the diagnosis of retinal detachment could not be excluded. RESULTS: Spectral domain optical coherence tomography scans obtained at the margin of the lesions demonstrated attached retina with a characteristic splitting of the neurosensory retina at the outer plexiform layer and cystic changes in the inner retina. CONCLUSIONS: Spectral domain optical coherence tomography can assist in the diagnosis of senile (acquired) retinoschisis, particularly in cases where retinal detachment cannot be excluded on clinical examination alone.

Time Domain Optical Coherence Tomography in Familial Vitreous Amyloidosis Associated Transthyretin Met30 Mutation.

Vitreous amyloidosis is characterized by progressive loss of vision from amyloid accumulation of deposits on the retina and in the vitreous. Time domain optical coherence tomography (TD-OCT) was used in a case of familial transthyretin vitreous amyloidosis Met30 mutation to image the anterior vitreous deposits, which showed high reflectivity of very different from vitreous found in unaffected individuals. TD-OCT may be a useful adjunctive test to diagnose vitreous amyloidosis when masquerade syndromes are suspected. There may be more easeful imaging in TD-OCT of vitreous abnormalities than with spectral domain OCT (SD-OCT). Further study should be performed comparing TD versus SD-OCT in families with vitreous amyloidosis and TD vitreous amyloidosis versus TD in other intermediate uveitis.

Anterior segment imaging: optical coherence tomography versus ultrasound biomicroscopy.

BACKGROUND AND OBJECTIVE: To determine the clinical indications of anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy in anterior segment imaging. PATIENTS AND METHODS: Eighty patients were evaluated using AS-OCT and ultrasound biomicroscopy. RESULTS: AS-OCT was ideal for detailed imaging of structures from the surface of the eye to the iris plane. Ultrasound biomicroscopy was ideal for imaging structures from the surface of the eye to the anterior vitreous. CONCLUSION: AS-OCT is indicated for imaging the conjunctiva, sclera, cornea, and iris, screening the angle, and visualizing subconjunctival, corneal, and anterior chamber implants. Coronal imaging, unique to AC Cornea OCT (Ophthalmic Technologies Inc., Toronto, Ontario, Canada), graphically defines structures viewed on cross-sectional OCT. Ultrasound biomicroscopy is indicated for imaging the conjunctiva, sclera, iris, lens, and ciliary body, for tumor measurements, for light-and-dark tests in glaucoma, and for viewing subconjunctival, anterior chamber, posterior chamber, and pars plana implants.

Imaging implanted keratoprostheses with anterior-segment optical coherence tomography and ultrasound biomicroscopy.

PURPOSE: To describe the anterior ocular segment findings of eyes with implanted Boston type 1 keratoprostheses (KPro) in vivo by using anterior-segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM). METHODS: A retrospective, comparative study was made of patients with implanted KPros who were examined with AS-OCT (AC Cornea OCT) and UBM (OTI Scan 35-50 MHz Ultrasound). RESULTS: One pseudophakic and 1 aphakic eye were included in the study. Cross-sectional AS-OCT adequately imaged the components of the KPro (front plate with stem, back plate, and titanium ring), the corneal graft, and host cornea. The angles could be seen as open, filled with debris, or closed. Coronal AS-OCT showed en face views of each KPro part. Retrokeratoprosthetic membranes were depicted to be thick opacities covering the rear optical surface of the stem. UBM, on the other hand, imaged the KPro front plate as a muffin-shaped space at the apical center, with the corneal graft appearing wispy and the host cornea grainy. The back plate, titanium ring, and angles could not be resolved. Glaucoma tubes and posterior-chamber intraocular lens (PCIOL) haptics were imaged below the iris plane. CONCLUSIONS: Cross-sectional AS-OCT adequately imaged the components of the assembled KPro in vivo, as well as its interaction with surrounding anterior-segment structures. It allowed visualization of the anterior chamber, iris, and angle, essential in the postoperative care of these patients. Coronal AS-OCT showed graphic en face images of the KPro device and suspected retrokeratoprosthetic membranes. UBM, on the other hand, adequately imaged glaucoma tube shunts and PCIOL haptics beneath the iris plane.

Imaging through opaque corneas using anterior segment optical coherence tomography.

BACKGROUND AND OBJECTIVE: To investigate the capability of the prototype AC Cornea OCT (Ophthalmic Technologies Inc., Toronto, Ontario, Canada) for imaging eyes with opaque corneas. PATIENTS AND METHODS: More than 50 eyes of patients were included in the study. RESULTS: The density of opacification influenced the ability of OCT to reveal anterior segment details. Imaging was limited by shadows cast by abnormal pigmentation or vascularity within the cornea. However, the system's unique coronal perspective capability was helpful in revealing occult spatial relationships. CONCLUSIONS: The AC Cornea OCT is valuable for examining eyes with opaque corneas and provides cross-sectional and coronal views helpful in formulating specific management strategies.

Surface rendering of 3D ultrasound images in ophthalmology.

Surface rendering of three-dimensional ultrasound images is a novel way of imaging ophthalmic pathologies in vivo. The authors have evaluated surface rendering of three-dimensional ultrasound images in selected cases of opthalmic disease.

Peribulbar oncocytoma: high-frequency ultrasound with histopathologic correlation.

The clinical, ultrasonographic, and histopathologic characteristics of an oncocytoma of the conjunctiva are described. A 49-year-old woman presented with a red-orange lesion adjacent to the caruncle in her left eye. A clinical examination including high-frequency ultrasound was performed prior to excisional biopsy of her tumor. High-frequency ultrasound demonstrated an epibulbar tumor with low internal reflectivity and a cystic component. There was no involvement of the underlying sclera. Multiple hypoechoic components of the tumor stroma were correlated to multiple cystic glandular structures on histopathologic evaluation. The excised tumor was diagnosed to be an oncocytoma.

Wide-field handheld high frequency ultrasonography using a variable high frequency ultrasound system.

Wide-field handheld high frequency ultrasonography using a variable high frequency ultrasound system is an imaging modality in the frequency range of 35 to 50 MHz. Using a water bath immersion technique, high-resolution digital movies obtained from a variety of anterior segment ocular conditions were particularly helpful in establishing the diagnosis in each case. Images taken with the wide-field limbus-to-limbus mode provided a comprehensive picture of large and extensive lesions, whereas the focal mode was for small to medium lesions or specific areas of interest.

Optic nerve measurements by 3D ultrasound-based coronal "C-scan" imaging.

Twenty-three normal eyes were examined with the Intensity Profiling technique of 3D I-Scan and 52 normal eyes with the Automated technique of OTI-Scan 1000 ultrasound systems (Ophthalmic Technologies Inc., Toronto, Ontario, Canada). With the eye looking straight, the probe was applied on the temporal sclera. Scanning generated 3D image files. Coronal optic nerve measurements were obtained 3 mm behind the globe. The mean optic nerve sheath diameter was 4.8 mm (standard deviation = 0.6; range, 3.9 to 5.9 mm) with the Intensity Profiling technique, and 5.4 mm (standard deviation = 0.4; range, 4.4 to 6.0 mm) with the Automated technique. 3D ultrasound imaging can be used to obtain optic nerve measurements in vivo. Both the Intensity Profiling and the Automated techniques yielded measurements similar to current magnetic resonance imaging and computed tomography scan reports. Coronal "C-scan" sectioning can be used as a screening tool to measure optic nerve diameter prior to magnetic resonance imaging or computed tomography.

A 3-dimensional ultrasound C-scan imaging technique for optic nerve measurements.

PURPOSE: To evaluate the use of 3-dimensional ultrasound C-scan imaging for optic nerve diameter measurements. DESIGN: Prospective observational case series. PARTICIPANTS: Thirty-eight normal eyes of 32 healthy adults. METHODS: Coronal C-scans of 38 normal optic nerves were imaged 3 mm behind the globe. MAIN OUTCOME MEASURES: Optic nerve sheath diameter (ONSD) and optic nerve diameter (OND). RESULTS: Mean ONSD was 4.8 mm (range: 3.9-5.9; SD 0.6), whereas mean optic OND was 1.9 mm (range: 1.8-2.1; SD 0.1). Mean ONSDs were 4.9 mm (male), 4.5 mm (female), 5.0 mm (subjects younger than 50 years), and 4.6 mm (subjects 50 and older). CONCLUSION: Coronal C-scans generated from 3-dimensional ultrasound can be used to measure the optic nerve diameters in adult eyes.

Retinal blood flow in the normal human eye using the canon laser blood flowmeter.

PURPOSE: To establish a retinal blood flow database in normal human eyes using the Canon Laser Blood Flowmeter (CLBF). METHOD: Fourteen healthy subjects (7 males, 7 females) between the ages of 24 and 33 underwent birectional laser Doppler velocimetry (BLDV) in one eye using the CLBF. Measurements consisting of blood vessel diameter (D) in micrometers, velocity (V) in millimeters per second, and flow (F) in microliters per minute were recorded at sites along the major retinal veins. Four to six veins were measured in each eye. Total volumetric blood flow was calculated as the sum of the venous flow rates in the major veins. RESULTS: Total retinal blood flow could be reliably determined on 5 of the subjects (1 male, 4 females). Venous blood vessel diameter ranged from 84 to 177 microm. The correlations between D and F, as well as D and V were found to be significant. Specifically, the correlation coefficient between D and F was 0.885 (p < or = 0.001), while the log-log regression coefficient was 3.35 +/- 0.23 (p < or = 0.001). The correlation coefficient between D and V was 0.694 (p < or = 0.001), while the log-log regression coefficient was 1.43 +/- 0.27 (p < or = 0.001). Total venous blood flow showed a mean of 64.9 +/- (SD) 12.8 microl/min (range: 50.9-80.6 microl/min). Venous blood flow averaged 44.1 +/- 4.5 microl/min temporally and 20.8 +/- 9.2 microl/min nasally, showing a temporal retinal blood flow approximately twice that of the nasal retina (p < 0.001). On the other hand, venous blood flow averaged 30.6 +/- 9.8 microl/min superiorly and 34.3 +/- 8.0 microl/min inferiorly. These values showed no statistical difference. CONCLUSION: The average total retinal blood flow in 5 healthy subjects using the CLBF was 64.9 +/- 12.8 microl/min. Venous blood flow at the temporal retina was about twice that of the nasal retina, whereas flow at the superior and inferior retina showed no statistical difference. Our findings are comparable with studies done using a different BLDV system.