Faculty Bibliography

PURPOSE: This study was conducted to evaluate the effect of pupillary dilation on retinal nerve fiber layer (RNFL) thickness as measured by scanning laser polarimetry (SLP) in cataractous and noncataractous eyes. METHODS: The study included 31 eyes of 31 consecutive patients (mean age, 62.5 +/- 14.0 years; range, 30-76 years). Eyes with refractive error exceeding 5.0 D sphere or 2.0 D cylinder, nonlenticular media opacity, cup-to-disc ratio > 0.9, corneal disease, ocular inflammation, or previous intraocular surgery were excluded. A standard reticule was used to measure pupillary diameter. Cataract grade was evaluated by a single observer using the Lens Opacities Classification System (LOCS III). RNFL thickness measurements were obtained by means of SLP before and after pupillary dilation. RESULTS: Of the patients, 10 had clear lenses and 21 had variable degrees of lenticular opacification. In four eyes, imaging could not be performed because of dense cataracts. Mean pupillary diameters before and after dilation were 2.5 +/- 0.7 mm and 7.3 +/- 1.1 mm, respectively. There were no significant differences in global RNFL thickness before and after dilation in noncataractous and cataractous eyes. Among cataractous eyes in which imaging was possible, there was no correlation between difference in RNFL thickness before and after dilation and nuclear opalescence, nuclear color, and cortical and posterior subcapsular grading of the LOCS III score. Six of 27 eyes (22.2%) had a change of more than 10% in RNFL thickness after pupillary dilation. CONCLUSION: Although pharmacologic mydriasis does not statistically alter RNFL thickness as measured by SLP, approximately one fifth of such eyes will have a change of more than 10% in retardation. Uniformity in pupil size is recommended when longitudinally evaluating RNFL measurements

OBJECTIVE: To evaluate changes in anterior segment anatomy after laser iridotomy for pigment dispersion syndrome. METHODS: Ultrasound biomicroscopy was performed on 7 eyes of 7 untreated patients with reverse pupillary block and pigment dispersion syndrome. A radially oriented image with the probe perpendicular to the eye in the superior meridian was obtained before and at least 1 week after laser iridotomy in each eye. We assessed changes in angle recess area and iris-lens contact distance. RESULTS: Mean +/- SD patient age was 31.3 +/- 5.7 years and mean +/- SD refractive error was -5.0 +/- 3.9 diopters. Angle recess area (mean +/- SD, 0.78 +/- 0.28 vs 0.35 +/- 0.11 mm2; P=.001, paired t test) and iris-lens contact distance (2.05 +/- 0.28 vs 0.79 +/- 0.13 mm; P<.001) decreased following iridotomy. Central anterior chamber depth did not change. CONCLUSION: Flattening of the iris following laser iridotomy for pigment dispersion syndrome causes a decrease in iris-lens contact and angle width while lens position remains constant

PURPOSE: To develop a uniform file format of ocular imaging data, including, but not limited to, ultrasound biomicroscopy, optical coherence tomography, and nerve fiber analyzer, capable of being transmitted via Internet or intranet for collaborative research and telemedicine use. METHOD: File filters were developed as dynamic link libraries (DLLs). These can read the original raw data format of each ocular imaging device. A data file format was also designed to describe these raw data uniformly in three different types of compression: noncompressed, run length compression, and differential pulse code modulation (DPCM). These three file formats were then tested in the following aspects: file size, speed of reading, and speed of writing. RESULTs: Run length compression failed to compress raw data, while DPCM compressed raw data successfully (< or =35.5%). The speed of reading and writing files was slowest in DPCM. However, the actual time of reading and writing was fast enough (<0.6 s) for daily work regardless of file compression methods. CONCLUSION: The format designed has robust potential to be the standard file format for transmission of any ocular imaging raw data

OBJECTIVE: To correlate the clinical, histopathologic, and ultrasound biomicroscopic characteristics of anterior segment implantation cysts. METHODS: We performed a retrospective review of 7 cases of secondary anterior segment implantation cysts. We reviewed the clinical history, visual acuity, clinical findings, and ultrasound biomicroscopic characteristics in all cases. Histopathologic correlation was possible in 4 cases. RESULTS: Six eyes had been subjected to major trauma prior to cyst formation. Trauma was noted as blunt in 3 eyes and surgical in 3 eyes. The diagnosis was confirmed in 1 eye when conjunctival cells were aspirated on fine needle biopsy. Ultrasound biomicroscopy revealed large (mean +/- SD greatest diameter, 4.7 +/- 0.9 mm) cystic tumors. In 1 patient, a cyst-related indentation of the anterior lens surface was seen. Ultrasonographic evaluations of internal reflectivity revealed thick, moderately reflective cyst walls encapsulating a relatively hypoechoic core. In 3 cases, the cyst contents consisted of variably reflective material. The other 4 were completely sonolucent. Histopathologic correlation showed that the cyst walls were lined with stratified squamous epithelium. The moderately reflective cyst contents were found to be degenerated conjunctival cells with inflammatory foci and cholesterol crystals. The sonolucent regions correlated with inflammatory cells and fluid. CONCLUSIONS: This study demonstrates that implantation cysts are unilateral, large, and thick walled. They may be sonolucent or exhibit variable internal reflectivity. These findings as well as the extent of anterior segment involvement (particularly posterior extension) could be evaluated by ultrasound biomicroscopy prior to surgery

BACKGROUND: High-frequency ultrasound biomicroscopy has allowed eye care specialists to evaluate posterior extension of anterior segment tumors. This article evaluates the role of ultrasound biomicroscopy for the diagnosis and management of anterior segment tumors. METHODS: Fourteen patients with anterior segment tumors were selected for evaluation. Each patient underwent a complete clinical examination followed by slit-lamp photography and ultrasound biomicroscopy. RESULTS: Unlike standard ultrasonography of anterior segment tumors, high-frequency ultrasound biomicroscopy allowed quantitative measurements of tumor size, extension within and posterior to the iris, as well as differentiation of solid and cystic lesions. These characteristics were used to differentially diagnose anterior segment tumors and document the response of iridociliary body melanomas to radiotherapy. CONCLUSIONS: This study demonstrates how ultrasound biomicroscopy has become an effective and necessary procedure, used for both the diagnosis and management of anterior segment tumors

PURPOSE: To evaluate the ultrasound biomicroscopic appearance of anterior segment foreign bodies under clinical and experimental conditions. METHODS: Ultrasound biomicroscopy was performed on 4 eyes of 4 patients referred for evaluation of anterior segment trauma and known or suspected intraocular foreign body. Imaging of wood, aluminum, concrete, and glass foreign bodies was performed in the anterior chamber of a human cadaver eye. RESULTS: Ultrasound biomicroscopy verified the location of a foreign body in two patients and identified occult foreign bodies in two others. Under clinical and experimental conditions, intraocular aluminum and glass produced comet tail artifacts. Under experimental conditions intraocular wood and concrete produced shadowing artifacts. CONCLUSION: Ultrasound biomicroscopy provides useful information in the evaluation of known and occult anterior segment foreign bodies. Ultrasound patterns of shadowing and comet tail may help differentiate foreign body materials

BACKGROUND AND OBJECTIVE: To illustrate artifacts that may be encountered during measurement of the peripapillary retinal nerve fiber layer (RNFL) using scanning laser polarimetry (SLP). PATIENTS AND METHODS: A total of 426 patients with a variety of ocular diagnoses underwent RNFL measurements using SLP from June 1996 to April 1997. Scanning was performed by two operators whose reproducibility of measurements had been previously validated. Images were selected to illustrate clinical features that adversely affected measurement of the thickness of the RNFL. RESULTS: Image acquisition was difficult in eyes with corneal grafts or edema, keratic precipitates, anterior uveitis, posterior subcapsular cataract, vitreous opacity, peripapillary atrophy, posterior staphyloma, and high axial myopia. These scans resulted in poor clinical correlation with visual field tests and optic nerve examination, poor reproducibility of images, and unreadable images. CONCLUSION: Anterior and posterior segment pathologies, particularly those localized to the cornea and lens, may produce spurious RNFL measurements and should be carefully considered prior to clinical decision making

PURPOSE: The authors determine the safety and effectiveness of pericardial patch grafts in glaucoma implant surgery. METHODS: A retrospective chart review was conducted on all patients who underwent a glaucoma implant procedure with the use of a pericardial patch graft to cover the subconjunctival portion of the tube at The New York Eye and Ear Infirmary between September 1, 1995 and June 30, 1996. Charts were assessed for evidence of delle formation, graft rejection, graft-related infection, graft thinning, or tube erosion. RESULTS: Forty-four eyes of 44 patients were enrolled. Mean follow-up was 10.2 +/- 4.0 months (range, 2.3 to 18.6 months). Infection, tube erosion, graft rejection, and graft-related inflammation did not occur. Five eyes were noted to have asymptomatic thinning of the patch without evidence of tube erosion. CONCLUSIONS: Preserved human cadaveric pericardial patch grafts appear to be well-tolerated for use with glaucoma drainage devices. As with other grafting material, potential for graft thinning is possible and further long-term experience is needed

PURPOSE: The authors assess the reproducibility of retinal nerve fiber layer (RNFL) thickness measurements using scanning laser polarimetry. METHODS: The right eyes of five healthy individuals were scanned by two trained operators (S.T.H., H.I.) using the Nerve Fiber Analyzer II (Laser Diagnostic Technologies, Inc., San Diego, CA, U.S.A.). Each participant was scanned six consecutive times per session for five sessions carried out over separate days within a two-week period. Intra- and interoperator measurement reproducibility was assessed. RESULTS: Intraoperator reproducibility was high. Mean coefficients of variation for total RNFL thickness measurements were 4.48 +/- 1.76% and 4.92 +/- 2.32% for operators 1 and 2, respectively. Interoperator reproducibility was high (p = 0.20-0.93) if a single ellipse was applied to the images of both examiners. However, measurement reproducibility worsened if each operator created his own measurement ellipse (p < or = 0.05 for 3 out of 5 participants). CONCLUSION: Interoperator error in image analysis can be minimized by using a single ellipse for the baseline and all subsequent scans even if subsequent scans are acquired by different operators