Optic disc morphology in eyes after nonarteritic anterior ischemic optic neuropathy

PURPOSE: Parapapillary chorioretinal atrophy, neuroretinal rim loss, and a decrease of retinal vessel diameter have been described to occur in glaucomatous eyes. This study was conducted to evaluate the frequency and degree of these signs in nonarteritic anterior ischemic optic neuropathy (AION). METHODS: We evaluated morphometrically and compared stereo color optic disc photographs of 17 patients after AION, 184 patients with primary open-angle glaucoma, and 98 normal subjects. RESULTS: The optic disc area and retinal vessel diameter were significantly smaller and the visibility of the retinal nerve fiber bundles was significantly reduced in patients after nonarteritic AION compared with that of the normal subjects. The optic disc shape, area, and form of zones alpha and beta of the parapapillary chorioretinal atrophy and the size and form of the neuroretinal rim did not differ significantly between these two groups. In the group of eyes with glaucoma, the neuroretinal rim was significantly smaller and the parapapillary chorioretinal atrophy was significantly larger than in the group of eyes with AION. Visibility of the retinal nerve fiber bundles and retinal vessel caliber did not differ statistically between the eyes with AION and those with glaucoma. CONCLUSIONS: These results indicate that the parapapillary chorioretinal atrophy is not larger in eyes after nonarteritic AION compared with normal eyes. They show that the area and shape of the neuroretinal rim, as determined planimetrically, may not markedly change after nonarteritic AION. They confirm previous reports on a small optic disc size as a risk factor for nonarteritic AION. They agree with findings of a reduced retinal vessel caliber in eyes with optic nerve damage, independently of the cause.     

Laser scanning tomography of the optic nerve head in ocular hypertension and glaucoma

BACKGROUND: This study evaluated the ability of laser scanning tomography to distinguish between normal and glaucomatous optic nerve heads, and between glaucomatous subjects with and without field loss. METHODS: 57 subjects were classified into three diagnostic groups: subjects with elevated intraocular pressure, normal optic nerve heads, and normal visual fields (n = 10); subjects with glaucomatous optic neuropathy and normal visual fields (n = 30); and subjects with glaucomatous optic neuropathy and repeatable visual field abnormality (n = 17). Three 10 degrees image series were acquired on each subject using the Heidelberg retina tomograph (HRT). From the 14 HRT stereometric variables, three were selected a priori for evaluation: (1) volume above reference (neuroretinal rim volume), (2) third moment in contour (cup shape), and (3) height variation contour (variation in relative nerve fibre layer height at the disc margin). Data were analysed using analysis of covariance, with age as the covariate. RESULTS: Volume above reference, third moment in contour, and mean height contour were significantly different between each of the three diagnostic groups (p < 0.001). Height variation contour showed no significant difference among the three diagnostic groups (p = 0.906). CONCLUSIONS: The HRT variables measuring rim volume, cup shape, and mean nerve fibre layer height distinguished between (1) subjects with elevated intraocular pressures and normal nerve heads, and glaucomatous optic nerve heads, and (2) glaucomatous optic nerve heads with and without repeatable visual field abnormality. This study did not directly assess the ability of the HRT to identify patients at risk of developing glaucoma. It is hypothesised that the greatest potential benefit of laser scanning tomography will be in the documentation of change within an individual over time.     

Neuroretinal rim width ratios in morphological glaucoma diagnosis

AIMS: To evaluate the inferior to temporal neuroretinal rim width ratio and superior to temporal rim width ratio as measures of rim shape for diagnosis of glaucoma. METHODS: Colour stereo optic disc photographs of 527 normal subjects, 100 ocular hypertensive individuals with normal visual fields, and 202 open angle glaucoma patients with a mean perimetric defect of less than 10 dB were morphometrically evaluated. Eyes with an optic cup area of < 0.2 mm2 were excluded. RESULTS: In the normal subjects, inferior to temporal rim width ratio (1.67 (SD 0.53)) was significantly (p < 0.0001) higher than superior to temporal rim width ratio (1.56 (0.49)). Both ratios were significantly (p < 0.0001) higher the more vertically the optic disc was configured. In the normal eyes, both ratios were statistically independent of disc size, rim area, refractive error, age, and sex. With the differences being more marked for the inferior to temporal ratio than for the superior to temporal ratio, both rim width ratios were significantly (p < 0.005) lower in the ocular hypertensive group than in the normal group. Despite the high significance of the differences, diagnostic power of the inferior ratio and the superior ratio was 59% and 58%, respectively, indicating a marked overlap between the groups. CONCLUSIONS: Abnormally low inferior to temporal and superior to temporal rim width ratios can indicate glaucomatous optic nerve damage in some ocular hypertensive eyes. Being independent of optic disc size and ocular magnification, the rim width ratios may be taken as one among other variables for the ophthalmoscopic optic disc evaluation, taking into account, however, a pronounced overlap between normal eyes and ocular hypertensive eyes.     

The cupped disc. Who needs neuroimaging?

OBJECTIVE: To determine the incidence of positive neuroradiologic studies in consecutive patients with glaucoma associated with normal intraocular pressure and to compare the psychophysical and clinical characteristics of these eyes with eyes with disc cupping associated with intracranial masses. DESIGN: Retrospective case-controlled study. PARTICIPANTS: Fifty-two eyes of 29 patients with glaucoma associated with normal intraocular pressure and 44 eyes of 28 control patients with compressive lesions were reviewed. INTERVENTION: The medical records of consecutive glaucoma patients with normal intraocular pressure who underwent brain magnetic resonance imaging or computed tomography scanning as part of a diagnostic evaluation between January 1, 1985, and July 1, 1995, were reviewed. A masked reading of optic nerve photographs and visual fields was performed by one observer. A similar analysis was performed on a control group of consecutive patients with nonglaucomatous optic nerve cupping with known intracranial mass lesions. MAIN OUTCOME MEASURES: The neuroradiologic findings, clinical characteristics, optic nerve head appearance, and patterns of visual field loss were compared between groups. RESULTS: None of the patients diagnosed with glaucoma had neuroradiologic evidence of a mass lesion involving the anterior visual pathway. Compared to control subjects, patients with glaucoma were older (P = 0.0001), had better visual acuity (P = 0.002), greater vertical loss of neuroretinal rim tissue (P = 0.0001), more frequent optic disc hemorrhages (P = 0.01), less neuroretinal rim pallor (P = 0.0001), and more nerve fiber bundle visual field defects aligned at the horizontal midline (P = 0.0001). Visual acuity less than 20/40, vertically aligned visual field defects, optic nerve pallor in excess of cupping, and age younger than 50 years were 77%, 81%, 90%, and 93% specific for nonglaucomatous cupping associated with compressive lesions, respectively. CONCLUSIONS: Anterior visual pathway compression is an uncommon finding in the neuroradiologic evaluation of patients with a presumptive diagnosis of normal-tension glaucoma. Younger age, lower levels of visual acuity, vertically aligned visual field defects, and neuroretinal rim pallor may increase the likelihood of identifying an intracranial mass lesion.     

zALK-8, a novel type I serine/threonine kinase receptor, is expressed throughout early zebrafish development

AIMS: Progressive loss of neuroretinal rim tissue is known to occur early in glaucoma and measurement of the neuroretinal rim area is possible by magnification corrected analysis of optic disc photographs (planimetry). This study was performed to determine whether the facility to distinguish between glaucomatous and normal optic discs could be improved upon by: (a) taking into account the known relation between optic disc size and neuroretinal rim area, and (b) measuring rim area in a number of segments, in order to detect focal changes. METHODS: Planimetric examination of the optic disc photographs of 88 control subjects and 51 patients with early visual field defects was performed. In the control group, multiple linear regression analysis was performed between neuroretinal rim area and optic disc area, age, sex, eye side, refraction, and keratometry. This was repeated for the whole disc and for each of twelve 30 degree segments. Normal ranges were defined by the 98% prediction intervals of the regression analysis and the sensitivity and specificity for correct identification of optic discs in the two groups determined. RESULTS: Multiple linear regression demonstrated significant associations between the neuroretinal rim area and optic disc area and age in normal subjects. Sensitivity and specificity for glaucoma diagnosis, using the cut off derived from the 98% prediction intervals, was 37.7% and 98.9% respectively when total neuroretinal rim area alone was considered, and 88.7% and 94.3% respectively when the 30 degree segments were included. The most frequent pattern of neuroretinal rim loss was diffuse, followed by thinning in more than one sector and then by thinning in the inferotemporal sector alone. CONCLUSIONS: This method of optic disc analysis enables the examiner to identify glaucomatous optic discs at the stage of early perimetric loss with a high degree of precision. Optic disc photography is simple, and fundus cameras are widely available. This method for glaucoma case identification may therefore be suitable for the primary care setting as well as hospital practice.     

Bad ethics, good ethics and the genetic engineering of animals in agriculture

PURPOSE: The purpose of this retrospective study is to compare the measurements of intrapapillary and peripapillary parameters between two observers and test the usefulness of measuring different types of crescents. METHODS: Optic disc photographs of 23 eyes of 23 patients with glaucoma and 23 age-matched normal eyes were measured in Oulu and in Erlangen using manual planimetric techniques. The authors measured the following magnification corrected intrapapillary and peripapillary areas: optic disc, neuroretinal rim, cup: disc area ratio, scleral ring, central (zone beta), and peripheral peripapillary atrophy (zone alpha). Twenty-one patients with glaucoma had a follow-up of 3.2 years (range, 1.1-4.7 years), and follow-up for 19 control eyes was 3.7 years (range, 2.5-5.9 years). The measurements were performed in a masked fashion for the diagnosis and temporal sequence of the photographs. RESULTS: Central peripapillary atrophy (zone beta) was statistically significantly largest in primary open-angle glaucoma in both centers (Oulu, P=0.003; Erlangen, P=0.004), whereas normal and exfoliative eyes did not differ significantly from each other. The results for peripheral peripapillary atrophy (zone alpha) and scleral ring were less consistent. Despite statistically significant interobserver correlations ranging from r=0.30 (scleral ring area; P=0.0472) to r=0.97 (optic disc area; P=0.0001), the means of all parameters, except for zone alpha and beta, differed statistically significantly between the two observers. CONCLUSIONS: The central peripapillary atrophy, or zone beta, is the most reproducible parameter when measuring peripapillary atrophy in glaucoma. Nonetheless, its measurement is of limited usefulness in the recognition of glaucoma or progression of glaucomatous nerve damage.     

Identification of early glaucoma cases with the scanning laser ophthalmoscope

PURPOSE: This study aimed to define the confocal laser scanning ophthalmoscope (Heidelberg Retina Tomograph [HRT]) parameters that best separate patients with early glaucoma from normal subjects. STUDY DESIGN: A cross-sectional study. PARTICIPANTS: A total of 80 normal subjects and 51 patients with early glaucoma participated (average visual field mean deviation = -3.6 dB). INTERVENTION: Imaging of the optic nerve head with the HRT and analysis using software version 1.11 were performed. MAIN OUTCOME MEASURES: The relation between neuroretinal rim area and optic disc area, and cup-disc area ratio and optic disc area, was defined by linear regression of data derived from the normal subjects. The normal ranges for these two parameters were defined by the 99% prediction intervals of the linear regression between the parameter and optic disc area, for the whole disc, and for each of the predefined segments. Normal subjects and patients were labeled as abnormal if the parameter for either the whole disc or any of the predefined segments was outside the normal range. The sensitivity and specificity values of the method were calculated. RESULTS: The highest specificity (96.3%) and sensitivity (84.3%) values to separate normal subjects and those patients with early glaucoma were obtained using the 99% prediction interval from the linear regression between the optic disc area and the log of the neuroretinal rim area. Similar specificity (97.5%) and lower sensitivity (74.5%) values were obtained with the 99% prediction interval derived from regression between the disc area and cup-disc area ratios. Poor separation between groups was obtained with the other parameters. CONCLUSIONS: The HRT, using the technique of linear regression to account for the relationship between optic disc size and rim area or cup-disc area ratio, provides good separation between control subjects and patients with early glaucoma in this population.     

Influence of optic disc size on the sensitivity of the Heidelberg Retina Tomograph

PURPOSE: The aim of this study was to evaluate the influence of optic disc size on the ability of variables generated by the Heidelberg Retina Tomograph, software version 1.11, to distinguish glaucoma patients from normals in a cross-sectional study. PATIENTS AND METHODS: For evaluation of the optic disc with the Heidelberg Retina Tomograph, eyes of 87 normals and 61 glaucoma patients were selected. Disc area, volume above reference, rim area, cup area, cup volume, third moment in contour and the mean retinal nerve fibre layer thickness at the border of the optic disc were selected for evaluation. The sensitivity at 80% specificity of these variables was calculated under three conditions: (1) no correction for disc size; (2) calculation in the following disc size ranges: class I (1.0-2.0 mm2), class II (2.0-2.5 mm2), class III (2.5-3.15 mm2) and class IV (3.15-5.0 mm2); (3) calculation globally, taking into account the different disc sizes of the four classes. RESULTS: Neuroretinal rim area, cup area and volume, third moment and nerve fibre layer thickness were significantly and positively correlated with optic disc size in normals. Neuroretinal rim volume measurements were statistically independent of optic disc size. Sensitivity was lowest when the size of the optic disc was not considered. Sensitivity increased when evaluated in four optic disc size classes. With growing optic disc size sensitivity of the retinal nerve fibre layer increased and third moment value decreased. Cup volume and area had their lowest sensitivity for large optic discs. The area of the neuroretinal rim was the only variable which showed similar sensitivity values under all three conditions. CONCLUSIONS: The sensitivities of HRT variables varied with optic disc size. Evaluation of their sensitivity requires the definition of optic disc classes or statistical correction for the size of the optic disc.     

Optic disk appearance in ocular hypertensive eyes

We examined the optic disk appearance in ocular hypertensive eyes that had a normal result of conventional computed perimetry. Color stereo-optic disk photographs of 104 ocular hypertensive subjects and of 216 normal individuals were morphometrically evaluated. In the ocular hypertensive eyes as compared to the normal eyes, significant differences (P < .0001) were detected for a smaller area and an abnormal shape of the neuroretinal rim, larger zones alpha and beta of the parapapillary chorioretinal atrophy, a decreased visibility of the retinal nerve fiber layer, and a higher frequency of localized nerve fiber layer defects. The variables most useful to indicate optic nerve damage were an abnormal shape of the neuroretinal rim and a decreased visibility of the nerve fiber layer. The most specific variable was the presence of localized retinal nerve fiber layer defects. Evaluation of these variables may be helpful for the early diagnosis of glaucoma.     

Erythrocyte sodium-lithium countertransport activity and total body insulin-mediated glucose disposal in normoalbuminuric normotensive type 1 (insulin-dependent) diabetic patients

PURPOSE: To assess the potential of a clinical method of optic disc measurement in the detection of early neuroretinal rim loss in glaucoma. METHODS: A method of disc biometry based on indirect ophthalmoscopy was used to estimate disc and neuroretinal rim areas in 81 ocular hypertensive eyes of 43 patients and in 28 fellow eyes with normal visual fields of patients with unilateral visual field loss from primary open-angle glaucoma. The results were compared with those from age-matched visually normal patients. RESULTS: Neuroretinal rim area was significantly smaller in both hypertensive and fellow eye groups compared with controls (P < 0.0001; P = 0.0009). Disc area also was smaller in both groups (P = 0.0034; P = 0.046); however, this was inadequate to explain the differences in rim area, which, when corrected for disc size, were still highly significant (P < 0.0001; P = 0.0001). CONCLUSION: The differences in neuroretinal rim area observed are likely to indicate that a proportion of the eyes studied had suffered a reduction of neuroretinal rim area, which was measurable by this method at a stage before the development of demonstrable visual field loss.     

Analysis of depressive symptomatology in mood disorders

BACKGROUND: At this time little information is available about the relationship between glaucomatous visual field defects and impaired blood flow in the optic nerve head. The purpose of this study was to examine blood flow of the juxtapapillary retina and the rim area of the optic nerve head in primary open-angle glaucoma with a borderline visual defect. METHODS: Juxtapapillary retinal and neuroretinal rim area blood flow was measured by scanning laser Doppler flowmetry (SLDF). The visual field was evaluated by static perimetry (Octopus-G1). The optic nerve head was assessed on 15 degrees color stereo photographs. We examined 116 eyes of 91 patients with POAG with controlled IOP and 66 eyes of 44 healthy individuals. The POAG group was divided into eyes with a mean defect lower than 2 dB (POAG group I) and in eyes with a mean defect equal to or greater than 2 dB (POAG group II). The mean age of POAG group I and POAG group II was 55 +/- 11 years and 57 +/- 10 years, respectively. The mean age of the control group was 45 +/- 15 years. The eyes of POAG group I had an average C/D ratio of 0.71 +/- 0.18 with an average mean defect of the visual field of 0.97 +/- 0.68 dB; the eyes of POAG group II had an average C/D ratio of 0.80 +/- 0.17 with an average mean defect of the visual field of 8.2 +/- 6.0 dB. The intraocular pressure on the day of measurement in POAG group I was 18.2 +/- 3.7 mmHg, in POAG group II 17.6 +/- 4.0 mmHg, and in the control group 15.1 +/- 2.5 mmHg. For statistical analysis, age-matched groups of 32 normal eyes of 32 subjects (mean age 52 +/- 10 years) were compared to 18 glaucomatous eyes of 18 patients (POAG group I, mean age 55 +/- 11 years) and 59 glaucomatous eyes of 59 patients (POAG group II, mean age 55 +/- 10 years). RESULTS: In the eyes of POAG group I and POAG group II, both juxtapapillary retinal blood flow and neuroretinal rim area blood flow were significantly decreased compared to an age-matched control group: neuroretinal rim area "flow" POAG group I -65%, POAG group II -66%; juxtapapillary retina "flow" POAG group I -52%, POAG group II -44%. All eyes of the POAG group I (MD < 2 dB) and 56 of 61 eyes of the POAG group II (MD > = 2 dB) showed a retinal perfusion lower than the 90% percentile of normal blood flow. We found no correlation between reduction of juxtapapillary or papillary blood flow and mean defect in POAG eyes. CONCLUSION: Glaucomatous eyes with no defects or borderline visual field defects as well as glaucomatous eyes in an advanced disease stage show significantly decreased optic nerve head and juxtapapillary retinal capillary blood flow.     

Unilateral testing of utricular function

PURPOSE: To examine acquired pit of the optic nerve as a risk factor for progression of glaucoma. METHODS: In a retrospective longitudinal study, 25 open-angle glaucoma patients with acquired pit of the optic nerve were compared with a group of 24 open-angle glaucoma patients without acquired pit of the optic nerve. The patients were matched for age, mean intraocular pressure, baseline ratio of neuroretinal rim area to disk area, visual field damage, and duration of follow-up. Serial optic disk photographs and visual fields of both groups were evaluated by three independent observers for glaucomatous progression. RESULTS: Of 46 acquired pits of the optic nerve in 37 eyes of 25 patients, 36 pits were located inferiorly (76%) and 11 superiorly (24%; P < .001). Progression of optic disk damage occurred in 16 patients (64%) in the group with acquired pit and in three patients (12.5%) in the group without acquired pit (P < .001). Progression of visual field loss occurred in 14 patients (56%) in the group with acquired pit and in six (25%) in the group without pit (P=.04). Bilateral acquired pit of the optic nerve was present in 12 patients (48%). Disk hemorrhages were observed more frequently in the group with acquired pit (10 eyes, 40%) compared with the group without pit (two eyes, 8%; P=.02). CONCLUSION: Among patients with glaucoma, patients with acquired pit of the optic nerve represent a subgroup who are at increased risk for progressive optic disk damage and visual field loss.     

Iatrogenic posterior tibial nerve division during ankle arthroscopy

AIM: To evaluate the validity of cumulative rim/disc area (RA/DA) curve analysis as a clinical tool for the identification of glaucoma induced optic disc pathology. METHODS: 71 normal and 83 glaucomatous eyes were evaluated from a series of 154 subjects recruited for this study. For each eye, the cumulative distribution of RA/DA was calculated from 36 equally spaced rim sectors of each optic disc obtained by the automatic evaluation of simultaneous videographics (Image-net X Rev.3/51b). To increase the sensitivity of this analysis in early glaucoma and in normal eyes, these cumulative curves were subsequently divided into two equal segments and the slopes of their respective regression lines compared. RESULTS: The median RA/DA value obtained from the 36 sectors was significantly different in glaucomatous eyes compared with normals (p < 0.001). Nevertheless, the curves (5th-95th percentile of the cumulative curves distribution) of early glaucomatous eyes fell within the normal range. When the cumulative curve of these marginal cases was then divided into two equal segments, the comparison of the slopes of the regression lines showed a significant difference (p < 0.05) in 100% of early glaucomatous eyes. Furthermore, normal eyes were shown to be true negatives in 93% of the cases in which no significant difference between the two slopes was observed. CONCLUSION: Analysis of the RA/DA cumulative curve from 36 sectors of the optic disc was a valid method for the identification of glaucomatous disc pathology; however, a further calculation of the slopes of the two RA/DA regression lines was needed to identify early glaucomatous damage.     

The cumulative normalised rim/disc area ratio curve

BACKGROUND: The assessment of the cup of the optic disc depends, among other criteria, on the disc area. A small cup in a small optic disc can indicate an advanced glaucomatous lesion, while on the other hand a large cup in a large optic disc can be normal. Therefore, a cumulative normalised rim/disc area ratio curve could help to distinguish between glaucomatous and normal optic cups. The aim of our study was to calculate normalised rim/disc area ratio curve. METHODS: Heidelberg Retina Tomograph examinations of the optic nerve head of 100 randomly selected eyes of 100 normal subjects were evaluated. We calculated the disc area-adjusted normalised rim/disc area ratio in sectors of 10 degrees. The 95th, 90th and 50th percentiles of each of the 36 sectors were displayed in descending order. RESULTS: In relation to the normal percentile curves, it is possible to display an individual normalised rim/disc area ratio curve. We obtained such curves for a normal optic disc, optic nerve heads with moderate and advanced lesions and a small optic disc with glaucomatous damage. CONCLUSION: We present a new display mode for the results of Heidelberg Retina Tomograph optic nerve head examination, which may be helpful for easy and reliable assessment of the local, diffuse and combined components of glaucomatous optic nerve head damage depending on optic disc size.     

Aging changes of the optic nerve head in relation to open angle glaucoma

AIMS: To determine the age related changes in optic nerve head structure in a group of normal subjects and assess the significance of any changes in relation to those found in open angle glaucoma. METHODS: A group of 88 white volunteers and friends and spouses of patients with a normal visual field and normal intraocular pressure was studied. Two different imaging and measurement devices were used (computer assisted planimetry and scanning laser ophthalmoscopy), and the results from each were compared. Measurements were made of the optic disc, optic cup, and neuroretinal rim areas, and the vertical optic disc diameter and cup/disc diameter ratio. RESULTS: Neuroretinal rim area declined at the rate of between 0.28% and 0.39% per year. Vertical optic cup diameter and optic cup area increased with age. The mean cup/disc diameter ratio increased by about 0.1 between the ages of 30 and 70 years. CONCLUSIONS: Age related changes are significant and measurable, and should be taken into account when assessing the glaucoma suspect, and when estimating the rate of progression of glaucomatous optic neuropathy in patients with established disease.     

Sensitivity and specificity of optic disc variables and analysis of a new variable (MP/D) for glaucoma diagnosis with the Glaucoma-Scope

AIM: In an attempt to use the quantitative optic disc measurements of the Glaucoma-Scope (OIS Sacramento, CA, USA) to distinguish glaucomatous from normal optic discs, a new variable was investigated, the mean disc corrected for the disc size by dividing by the disc area: MP/D. METHODS: Glaucoma-Scope disc evaluation was performed on 81 eyes of 51 patients split into the following groups based on Humphrey 24-2 visual field and clinical criteria of glaucoma: chronic glaucoma n = 27 (including only early, n = 17, and low tension glaucoma, n = 10), ocular hypertension n = 24, pseudoglaucomatous large discs, n = 12, and normal eyes, n = 18. Classic optic disc variables (the vertical and horizontal c/d ratios, and the c/d area) were compared with the new MP/D index calculating receiver operating characteristic curves. RESULTS: The MP/D ratio was able to identify the glaucomatous eyes more easily than other ratios. Areas under the curves were: 0.91 (MP/D); 0.87 (c/d area); 0.85 (c/d vertical); and 0.80 (c/d horizontal). The MP/D index was also correlated with the mean deviation (r = 0.466; p = 0.001). CONCLUSION: MP/D may prove useful in detecting glaucomatous optic nerve damage and could be an interesting screening tool for primary open angle glaucoma.     

Clinicopathological characteristics of skipping lymph node metastases in patients with colorectal cancer

We evaluated the optic disc in 77 eyes of 77 normal volunteers using a scanning laser tomograph (Heidelberg Retina Tomograph: HRT, version 1.11). Particular attention was paid to age, refractive error, and disc size. The topographic parameters included: cup area, C/D area ratio, rim area, cup volume, rim volume, mean cup depth, maximum cup depth, cup shape measure, height variation contour, mean RNFL thickness, and RNFL cross section area. There was a significant decline in mean RNFL thickness and RNFL cross section area with increase in age (p < 0.05). The mean and maximum cup depths were significantly deeper in myopic eyes (p < 0.05). Large discs had large values of cup area, C/D area ratio, rim area, cup volume, mean cup depth, cup shape measure (p < 0.01), and maximum cup depth (p < 0.05). Large discs had small values of mean RNFL thickness and RNFL cross section area. Rim volume was independent of age, refractive error, or disc area.     

Determination of long-life radiocesiums Cs-134 and Cs-137 in food by gamma-ray spectrometry: summary of collaborative study

PURPOSE: The authors evaluated the ability of a confocal scanning laser ophthalmoscope to detect glaucomatous visual field loss by using their previously described discriminant formula on a prospectively obtained cohort. The relationship of optic disc size to diagnostic classification was also evaluated. METHODS: One eye was chosen randomly from each of 153 subjects. Sixty control eyes had intraocular pressure less than 21 mmHg and normal visual fields; 93 glaucomatous eyes had intraocular pressure greater than 21 mmHg and abnormal visual fields. The optic disc status purposely was not used for classification purposes. All subjects were examined with the Heidelberg Retina Tomograph (HRT; Heidelberg Engineering GMBH, Heidelberg, Germany) and Humphrey Perimeter, program 30-2 (Humphrey Instruments, Inc., San Leandro, CA). Visual fields were considered abnormal by the authors' previously published criteria. The HRT classification used age, adjusted cup shape measure, rim volume, and height variation contour to classify the optic disc as normal or glaucomatous. Then the authors assessed the sensitivity, specificity, and diagnostic precision for the entire group, and for three subsets classified by disc area: disc area less than 2 mm2, between 2 and 3 mm2, and more than 3 mm2. RESULTS: The entire group had a sensitivity, specificity, and diagnostic precision of 74%, 88%, and 80%, respectively. The specificity was 83% when disc area was less than 2 mm2 and improved to 89% when disc area was more than 2 mm2. The sensitivity tended to improve from 65% to 79%, and to 83% if the disc area increased, but the difference was not statistically significant. CONCLUSIONS: In a prospective cohort of patients, the HRT discriminant analysis formula was capable of detecting glaucomatous visual field loss with good precision. Unusually small optic discs continue to present diagnostic difficulties.     

Foveal dysfunction and central visual field loss in glaucoma

OBJECTIVE: To determine whether foveal function distal to the ganglion cell layer is an independent predictor of central visual field function in glaucoma. SETTING: University affiliated hospital and private practice. PARTICIPANTS: Twenty-seven eyes (27 patients) with normal-pressure glaucoma, 10 eyes (10 patients) with primary open-angle glaucoma, and 47 eyes of 47 matched normal volunteers. INTERVENTION AND MAIN OUTCOME MEASURES: Foveal cone electroretinogram (ERG) amplitude, relative optic cup to disc area and their relations to Humphrey full-threshold 30-2 visual field central 4-point mean total deviation (C4MTD) and pattern deviation (C4MPD). RESULTS: Foveal cone ERG amplitude was subnormal in 14 (37.8%) of the 37 glaucomatous eyes and lower in the glaucoma group compared with normal eyes (P<.01). The C4MTD and C4MPD were lower in glaucomatous eyes with subnormal amplitudes compared with those with normal amplitudes (P<.01 and P<.05, respectively). Amplitude was directly correlated with C4MTD (P<.01) and C4MPD (P<.01). Relative optic cup to disc area was inversely correlated with C4MTD (P<.001) and C4MPD (P<.001). Partial correlation analysis revealed that amplitude and relative optic cup to disc area were independent predictors of C4MTD and C4MPD. CONCLUSION: Foveal function distal to the ganglion cell layer and optic disc cupping independently predict central visual field function in glaucoma.     

The relationship between deterioration and reversal of optic disc cupping in monkeys with chronic experimental high-pressure glaucoma

PURPOSE: To investigate the correlation between the deterioration in optic disc cupping during the chronic elevation of intraocular pressure (IOP) and the reversal of cupping during a subsequent reduction in IOP in experimental glaucoma. METHODS: We examined changes in the vertical and horizontal cup to disc ratios, the rim area to disc area ratio, and the cup volume to disc area ratio in 11 monkey eyes with laser-induced glaucoma using computerized stereo-image analysis. Correlations between changes in disc parameters during a spontaneous IOP reduction and changes in disc parameters during a period of chronic IOP elevation from baseline before laser exposure (baseline) to before the IOP reduction (pre-IOP reduction) and during the period from baseline to after the reduction in IOP (post-IOP reduction) were determined by linear regression analysis. RESULTS: All disc parameters improved significantly during IOP reduction and deteriorated significantly during the periods from baseline to the pre-IOP reduction and from baseline to the post-IOP reduction. The degree of reversal in disc parameters was correlated with the deterioration from baseline to the pre-IOP reduction and from baseline to the post-IOP reduction in the vertical cup to disc ratio (r = 0.68, P = 0.0218 and r = 0.97, P < 0.0001, respectively), the horizontal cup to disc ratio (r = 0.57, P = 0.0649 and r = 0.98, P < 0.0001, respectively), the rim area to disc area ratio (r = 0.68, P = 0.0227 and r = 0.98, P < 0.0001, respectively), and the cup volume to disc area ratio (r = 0.67, P = 0.0256 and r = 0.88, P = 0.0004, respectively). CONCLUSION: The degree of deterioration in cupping from baseline before the induction of glaucoma may be an important determinant of the degree of cupping reversal during subsequent reductions in IOP in primate glaucoma.