Julian P S Garcia

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 µm. 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 ≤ 0.001), while the log-log regression coefficient was 3.35 ± 0.23 (p ≤ 0.001). The correlation coefficient between D and V was 0.694 (p ≤ 0.001), while the log-log regression coefficient was 1.43 ± 0.27 (p ≤ 0.001). Total venous blood flow showed a mean of 64.9 ± (SD) 12.8 µl/min (range: 50.9–80.6 µl/min). Venous blood flow averaged 44.1 ± 4.5 µl/min temporally and 20.8 ± 9.2 µl/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 µl/min superiorly and 34.3 ± 8.0 µl/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 µl/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.

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.

Angle closure after Boston keratoprosthesis.

Purpose:To evaluate changes in the anterior chamber angle after Boston keratoprosthesis (KPro) placement. Patients/Methods:Ten patients were serially imaged with anterior segment optical coherence tomography after Boston KPro surgery. Angles were judged to be open or closed in the horizontal axis. Results:Seven of 10 patients had open angles before KPro placement. Within 4 months, 4 of 7 patients developed angle closure. Contact between the iris and the backplate was seen in 3 of these patients. Two of the 4 eyes demonstrated progressive angle closure. Intraocular pressure was elevated in 3 patients postoperatively due to the obstruction of a glaucoma drainage device tube (1 eye) and angle closure (2 eyes). Conclusions:After Boston KPro surgery, patients must be carefully monitored for the onset or progression of glaucoma. Progressive angle closure can occur after placement of a Boston KPro and may be seen in conjunction with irido-backplate touch.

3D ultrasound coronal C-scan imaging for optic nerve sheath meningioma

The use of three dimensional (3D) ultrasonography (3DUS) for optic nerve measurements has been described in normal eyes utilising coronal “C-scans.”1,2 This study demonstrates the use of 3DUS generated C-scans for optic nerve measurements in orbits with optic nerve sheath meningioma and compares those with measurements obtained from computed tomography (CT) scans. A 69 year old woman with a left optic nerve sheath meningioma was treated with external beam radiation therapy 6 years earlier. On 3DUS coronal C-scans, an optic nerve sheath diameter (ONSD) 3 mm behind the globe was measured to be 7.4 mm in the left eye (fig 1, top left) and 6.4 mm in the right (fig 1, top right). Figure 1  Case 1. The patient’s left (top left) and right (top right) optic nerve sheath diameters are shown …

“C-scan” ultrasound imaging of optic nerve extension of retinoblastoma

Three dimensional ultrasound based coronal “C-scan” imaging technique was used to demonstrate optic nerve extension of retinoblastoma. With a clinical diagnosis of retinoblastoma based on clinical evaluation, ultrasound, and computed radiographic tomography, this patient was treated by primary enucleation. Subsequent histopathological evaluation of the enucleated globe revealed three risk factors for metastatic retinoblastoma (including optic nerve extension).1,2 Both systemic chemotherapy and orbital radiation therapy were employed.3 A 2 year old black female presented with a 1 month history of conjunctival vascular dilation, leucocoria, strabismus, and ptosis involving the right eye. Slit lamp examination revealed a yellow-white tumour filling 70% of the anterior chamber and obscuring view of the posterior segment (fig 1A). Figure 1  (A) External photograph of the anterior segment filled with retinoblastoma. (B) 35 MHz high frequency ultrasound demonstrates tumour cells in both anterior and posterior chambers, and anterior vitreous (arrowhead). High frequency ultrasonography (35 MHz) demonstrated the presence of tumour cells in both the anterior and posterior chambers, as well …

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.

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.

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.