Performance of GDx VCC in eyes with peripapillary atrophy: comparison of three circle sizes.

PURPOSE: A scanning laser polarimetry (GDx VCC) equips three different sized measurement circles. In eyes with peripapillary atrophy (PPA), the GDx measurement becomes inaccurate when the circle falls on PPA. The aim of this study was to evaluate performance of the three circles of GDx measurement in eyes with PPA. METHODS: Three different sized circles were compared regarding frequency of PPA, which fell on each circle in 282 open-angle glaucoma (OAG) eyes, reproducibility of GDx parameters in 24 normal and 22 OAG eyes, and ability to detect glaucoma in 50 normal and 50 OAG eyes. RESULTS: PPA was observed in 230 (82%) of 282 OAG eyes. PPA fell on the small circle (default setting), medium, and large circles in 119 (43%), 38 (14%), and 12 (4%) of the 280 OAG eyes. Reproducibility of GDx parameters was not significantly different among three circles in normal eyes (P>0.05), whereas coefficients of reproducibility of TSNIT average (P=0.006) and superior average (P=0.035) were smaller in the smaller circles in OAG eyes. GDx parameters significantly correlated (P<0.001), but were significantly different (P<0.05) between the small and medium circles. The area under receiver operating characteristic curves for dividing OAG from normal eyes using GDx parameters was similar between the small and medium circles. CONCLUSIONS: If the medium circles were used, obstructing influences of PPA on GDx measurement could be avoided more often in Japanese OAG eyes with similar reproducibility and comparable ability to detect glaucoma compared to those with the default small circle.

Ultrasound biomicroscopic study of sclerotomy sites after implantation of sustained release drug devices.

BACKGROUND/AIMS: To evaluate the potential of ultrasound biomicroscopy (UBM) as a tool to study the precise location and changes of sclerotomy sites of the eye with an intraocular drug delivery device. METHODS: Eight eyes of six patients (13 sites) who received ganciclovir implants were examined by UBM. Examinations were performed 1-26 months (mean 12.8 months) postoperatively. Serial transverse and radial sections of the anterior ciliary body around the sclerotomy sites were obtained. RESULTS: The ganciclovir implant contour was successfully viewed using an UBM with high reflectivity. Three implants were deviated anteriorly and they were very close to the ciliary body and the lens (anterior deviation), while four implants were deviated posteriorly and away from the lens (posterior deviation). The other six implants were located at the appropriate position as intended. A solitary homogeneous mass with a medium reflectivity around the suture tab was observed at 12 out of 13 sites in seven eyes. Thick membranes extending from sclerotomy sites to the ora serrata were found at two sites in two eyes. CONCLUSION: UBM is helpful in detecting abnormal manifestations around ganciclovir implants and is a valuable tool to assess the changes of the sclerotomy sites of the sustained released intraocular devices.

Frequency doubling technology and confocal scanning ophthalmoscopic optic disc analysis in open-angle glaucoma with hemifield defects.

PURPOSE: To evaluate the potential of frequency doubling technology for detecting early glaucomatous damage. PATIENTS AND METHODS: Forty-nine eyes of 49 patients with open-angle glaucoma with visual field defects only in one hemifield according to the Humphrey Field Analyzer 30-2 program were included. Forty-five healthy patients were also included as control subjects. In each patient, frequency doubling technology with the threshold N-30 program and optic disc analysis using the Heidelberg Retina Tomograph was performed. Frequency doubling technology test results and the Humphrey Field Analyzer test results were compared. Optic disc parameters corresponding to the hemifield designated intact by the Humphrey Field Analyzer were compared between the eyes in which the hemifield was normal by frequency doubling technology and those in which the hemifield was abnormal. RESULTS: Forty-one percent of the 49 hemifields designated intact by the Humphrey Field Analyzer were abnormal based on frequency doubling technology, whereas 98% of the 49 hemifields designated defective by the Humphrey Field Analyzer were abnormal and 12% of the 90 hemifields designated intact by the Humphrey Field Analyzer were abnormal in healthy patients. The percentage of the hemifields designated abnormal by frequency doubling technology was significantly higher than that in healthy patients (P < 0.001). The rim volume was significantly smaller in eyes with abnormal results based on frequency doubling technology than in eyes with normal results (P < 0.05, paired t test, with Bonferroni correction for multiple comparison). CONCLUSION: Frequency doubling technology can detect glaucomatous damage earlier than conventional static perimetry can.

[Evaluation of optic disc in open-angle glaucoma with hemifield defect by Heidelberg retinal tomography].

OBJECTIVE: To investigate whether the glaucomatous optic disc change demonstrated by Heidelberg retinal tomography (HRT) is consistent to the distribution of the visual field defects and whether Heidelberg retinal tomography, (HRT) parameters in primary open angle glaucoma (POAG) and normal tension glaucoma (NTG) are different. METHOD: Sixty-four eyes of 64 patients with open angle glaucoma (27 of POAG, 37 of NTG) and hemifield abnormality detected by Humphery Field Analyzer (HFA) were tested by HRT. The HRT parameters and the visual field results were divided into two parts (0 degree-180 degrees and 180 degrees-360 degrees) for the corresponding analysis. RESULTS: Comparing with the half disc corresponding to the intact hemifield, the half disc corresponding to the defective hemifield has significantly higher values of cup/disc area ratio and cup shape measure, but has significantly lower values of rim area, the thickness and cross-section area of the retinal nerve fiber layer. No significant differences were found between NTG and POAG eyes in the HRT parameters of the half disc corresponding to the defective hemifield. CONCLUSIONS: The optic disc changes detected by HRT are consistent to the distribution of the visual field defects, cup/disc area ratio, cup shape measure, rim area, mean thickness and cross-section area of the retinal nerve fiber layer, and they are the relatively sensitive parameters. That the HRT parameters of NTG and POAG are similar suggests they possibly have certain similar mechanisms in the development of glaucomatous neuropathy.

Sound propagation and speech transmission in a branching underground tunnel.

The characteristics of sound propagation and speech transmission along a tunnel with a "T" intersection were investigated. At receivers within sight of the sound source, low frequencies were mainly attenuated around the intersection than high frequencies. At receivers out of sight of the source, high frequencies were extensively attenuated. The overall pattern of sound attenuation along the different sections of tunnel, which was calculated by the conical beam method, agreed well with the measurements in this study. Numerical calculations of reflected and diffracted waves with minimum transmission paths in a two-dimensional plane showed that reflected waves were the primary contributors to sound fields out of sight of the source. The articulation scores measured at receivers within sight of the source were high, and most of the confusion concerned syllables that could easily be misheard, even if there were a high signal-to-noise ratio. The types of syllable confusions observed at the receivers out of sight of the source appeared to have been caused by the greater deterioration in speech signals along this part of the tunnel, especially at high frequencies. The evaluation by rapid speech transmission indices (RASTI) appeared to be overestimated at the receivers out of sight of the source. Taking into account the early decay times of impulsive sound and the calculation procedures used in RASTI, it is concluded that speech intelligibility may not have been evaluated correctly by RASTI.

Usefulness of gaze tracking during perimetry in glaucomatous eyes

Purpose: To evaluate the usefulness of a new fixation monitoring system called gaze tracking in the perimetry of glaucomatous eyes. Subjects and Method: We studied the visual field of 106 eyes in 106 persons, comprising 74 eyes with open-angle glaucoma and 32 eyes with ocular hypertension. Perimetry was performed using a Humphrey Visual Field Analyzer 740/750 with a 30-2 full threshold program. We used two parameters for gaze tracking: the percentage of the time when the subject's eye deviated from the fixation target more than 3 degrees (G 3) and 6 degrees (G 6). These parameters were assessed in three groups: those with no visual field defect (group N), those with absolute visual field defect including the blind spot (group M 1), and others (group M 0).Result: The values of G 3 and G 6 were significantly correlated with the fixation loss in groups N and M 0 (P <.01). These values were not significantly correlated with the fixation loss in group M 1 (P.10). When the fixation loss was less than 20%, G 3 and G 6 values were significantly higher in group M 1 than in groups N or M 0.Conclusion: Gaze tracking is a useful fixation monitoring system particularly in the presence absolute visual field defect including the blind spot.

Influence of myopic disc shape on the diagnostic precision of the Heidelberg Retina Tomograph.

PURPOSE: To investigate the diagnostic capability of a glaucoma diagnostic classification program for the Heidelberg Retina Tomograph (HRT) in eyes with myopic disc shapes. METHODS: Sixty-six normal subjects (66 eyes) and 78 open-angle glaucoma patients (78 eyes) were enrolled. The eyes were divided into two groups; those eyes with myopic and those with nonmyopic disc shapes. The classification was based on clinical judgment made after the examination of stereophotographs of the discs without considering the refractive errors. The agreement between the classification program and the clinical diagnosis was evaluated for sensitivity, specificity, and diagnostic precision. The influence of the disc shape on the HRT topographic parameters was evaluated. RESULTS: The sensitivity, specificity, and diagnostic precision of the HRT were 83%, 95%, and 89% in eyes with nonmyopic disc shapes, but 71%, 96%, and 83% in those with myopic disc shapes. Rim volume, height variation contour, mean retinal fiber nerve layer (RNFL) thickness, and RNFL cross-section area were significantly larger in eyes with myopic disc shapes than in eyes with nonmyopic discs, regardless of the clinical diagnosis. CONCLUSIONS: The classification program should be modified to take into account the myopic disc shape in order to improve its capability to make more accurate diagnosis of glaucoma possible.

[Usefulness of gaze tracking during perimetry in glaucomatous eyes].

PURPOSE: To evaluate the usefulness of a new fixation monitoring system called gaze tracking in the perimetry of glaucomatous eyes. SUBJECTS AND METHOD: We studied the visual field of 106 eyes in 106 persons, comprising 74 eyes with open-angle glaucoma and 32 eyes with ocular hypertension. Perimetry was performed using a Humphrey Visual Field Analyzer 740/750 with a 30-2 full threshold program. We used two parameters for gaze tracking: the percentage of the time when the subject's eye deviated from the fixation target more than 3 degrees (G 3) and 6 degrees (G 6). These parameters were assessed in three groups: those with no visual field defect (group N), those with absolute visual field defect including the blind spot (group M 1), and other (group M 0). RESULT: The value of G 3 and G 6 were significantly correlated with the fixation loss in groups N and M 0 (p < 0.01). These values were not significantly correlated with the fixation loss in group M 1 (p > 0.1). When the fixation loss was less than 20%, G 3 and G 6 values were significantly higher in group M 1 than in groups N or M 0. CONCLUSION: Gaze tracking is a useful fixation monitoring system particularly in the presence of absolute visual field defect including the blind spot.

[Influence of myopic disc shape in a classification program of the Heidelberg retina tomograph].

PURPOSE: We investigated the influence of myopic disc shape on the diagnostic capability of a glaucoma diagnostic software (classification program) of the Heidelberg retina tomograph (HRT). SUBJECTS: 66 eyes of 66 normal subjects and 78 eyes of 78 patients with open-angle glaucoma were studied. The criterion of glaucoma was a visual field defect appearing between Aulhorn classification stage II and stage V regardless of the maximum intraocular pressure value. METHODS: The subjects were divided into eyes with a myopic disc and those with a non-myopic disc on the basis of stereo disc fundus photographs without considering the refractive errors. Agreement between the classification program and the clinical diagnosis was evaluated by the calculation of sensitivity, specificity, and diagnostic precision, and the influence of the disc shape on HRT disc shape parameters was also evaluated. RESULTS: Sensitivity, specificity, and diagnostic precision of the classification program were 83%, 95%, and 89% in the eyes with a non-myopic disc, and 71%, 96%, and 83% in the eyes with a myopic disc, respectively. Rim volume, height variation contour, mean RNFL (retinal nerve fiber layer) thickness, and RNFL cross section area were significantly larger in the eyes with a myopic disc than in those with a non-myopic disc regardless of the clinical diagnosis. CONCLUSION: The classification program should be modified to adjust to a myopia-like disc shape in order to improve the capability of the glaucoma predictive diagnosis.

Ultrasound biomicroscopy of ciliary body cysts.

PURPOSE: To report the incidence and sector distribution of ciliary body cysts in normal subjects and to assess association with age using ultrasound biomicroscopy. METHODS: We prospectively examined 232 eyes of 116 normal subjects (51 men and 65 women) ranging in age from 15 to 84 years (mean +/- SD, 45.2 +/- 20.1). Complete ophthalmic examination, including gonioscopy and ophthalmoscopy with mydriasis, was performed. In addition, the circumference of the ciliary body was divided into eight sectors, and scanned in transverse and radial sections by high-resolution ultrasound biomicroscope to determine the incidence, distribution, and location of cysts. RESULTS: Based on one randomly chosen eye from each subject, cysts were detected in 63 (54.3%) of the 116 subjects. Cysts were found most frequently and in greater numbers in the inferior and temporal sectors. The incidence and the distribution range, expressed as the number of involved sectors per eye, were 73.1% and 3.8, respectively, for subjects 20 approximately 29 years old; both incidence and the number of involved sectors decreased with age (P = .0001). Cyst diameter ranged from 200 to 2500 microm; mean size decreased with age (P = .001). Gender and refractive error did not affect the incidence and distribution. There was significant bilateral correlation in the number, incidence, and distribution of ciliary body cysts. CONCLUSION: Ultrasound biomicroscopy disclosed a high incidence of ciliary body cysts in normal subjects, which decreased with age. Cysts were multiple and bilateral in many subjects.