Measurement of the retinal nerve fiber layer thickness in clinical routine

The possibilities and limitations of methods for indirect and direct nerve fiber layer thickness (NFLT) measurements, and a summary of our own clinical studies using Optic Nerve Head Analyzer (Rodenstock, Munich, Germany) (ONHA), Laser Tomographic Scanner (Heidelberg Engineering, Heidelberg, Germany) (LTS), Heidelberg Retinal Tomograph (Heidelberg Engineering, Heidelberg, Germany) (HRT), Nerve Fiber Analyzer (Laser Diagnostic Technologies, San Diego, CA) (NFA) and Optical Coherence Tomography (OCT), together with the literature of the review period, are highlighted. A retinal hemifield test with the new parameters, retinal asymmetry difference and retinal asymmetry index, is introduced. These relative nerve fiber layer thickness (NFLT) measurement values are found to be independent of age, reference plane, and disc size. This reduces the interindividual variation of the measurements and may improve screening possibilities for glaucoma. The detection probability for nerve fiber bundle defects was found to be stage-dependent using HRT and NFA. For laser polarimetry, a decreasing correlation between NFLT and visual field loss with advanced glaucomatous disease was found. In the lower retina, a 6.9% higher NFLT was evident compared with the upper peripapillary NFLT in healthy eyes using NFA and OCT. This is not in correlation with perimetric retinal sensitivity, which was found to be 3.9% higher in the lower hemifield compared with the upper hemifield. In general, quantitative NFLT measures (HRT, NFA, OCT) were correlated with visual field loss in glaucoma. The interindividual variability of NFLT measurements, among other things, induces limitations on distinguishing beginning glaucoma from normals. Clinical and scientific significance and future directions of NFLT measurements are discussed.

[Can the extent of glaucoma damage be assessed by measuring the asymmetry of the peripapillary height profile between the upper and lower retinal half? A clinical study with the Heidelberg Retina Tomograph]

BACKGROUND

Peripapillary height measurements are possible using 2 different reference planes of the Heidelberg-Retina-Tomograph. It is not tested yet, whether the extent of glaucoma damage should be better quantified using reference plane 1 or 2.

PATIENTS AND METHODS

In 32 eyes of 32 glaucoma patients with a defined up-down asymmetry of visual field loss is tested I.) if there is a significant correlation between peripapillary height and visual field loss comparing reference plane 1 and 2. II.) if there is a conformable up-down asymmetry of the peripapillary height using a new "retinal-asymmetry-difference" (RAD). III.) if conformity between peripapillary height and visual field loss depends on the distance from the disc margin.

RESULTS

1.) For an advanced visual field loss there was a significant correlation between visual field loss and peripapillary height using reference plane 1. II.) In eyes with a big up-down asymmetry of visual field loss there was a bigger conformity between the up-down asymmetry of visual field loss and the up-down asymmetry of peripapillary height (11 of 12 eyes), as for a small up-down asymmetry (12 of 20 eyes). III.) Conformity decreases with the distance from the disc margin.

CONCLUSIONS

Peripapillary height should be examined using measurement circles near the disc margin. Because of its independence on the age and on different reference planes additional calculation of an up-down "retinal-asymmetry-difference" (RAD) seems to be useful. Using this up-down "retinal-asymmetry-difference" (RAD) a big up-down asymmetry of visual field loss, equivalent to an advanced glaucomatous disease, is quantified with high sensitivity.

[Improved eyedrop administration and compliance in glaucoma patients. A clinical study]

BACKGROUND

Poor compliance can be dangerous to successful medical treatment of glaucoma. Among other things one reason for non-compliance represents the inability of the patients to place drops in the eye appropriately. Therefore information regarding the patients ability to administer an eyedrop safely are a prerequisite to determining a therapy scheme which ensures the compliance of glaucoma patients.

PATIENTS AND METHODS

100 glaucoma patients on medical therapy who first presented in the outpatient glaucoma clinic of the University Eye Hospital of Würzburg were examined by standardised questionnaire and ability tests. We evaluated: 1. Can the eyedrop administration of glaucoma patients be improved by a standardised instruction? 2. Can the eyedrop administration be improved by the use of a drop aid (Autodrop)? 3. Can the accuracy of aiming and the manual ability be evaluated with a target-test on a sheet of paper with a series of concentric circles? 4. How do patients on combined therapy distinguish between their different bottles and where is the dosage regimen noted? 5. What kind of distinguishing marks of eyedrop-bottles do the patients prefer?

RESULTS

1. Before verbal instruction 76% of the patients applied the eyedrops appropriately, after instruction 94% (p < 0.001) were capable. Touching the eye with the tip of the dropper was reduced significantly. Touching the eye before instruction was found in 63% of the patients, after instruction it was found in 41% (p < 0.001). 2. When patients used the drop aid 81% were able to place a drop in the eye appropriately. Only by 46% of the patients the Autodrop was welcomed. 3. 16% of the patients were not able to place a drop within 1.5 cm of the center of the target (according to the size of an eye). 4. 47% of the patients who use more than one eyedrop bottle admitted problems in distinguishing the bottles, only 38% of the patients read the labels. 5. 76% of the patients would prefer markable stickers of different colours for the bottom of the bottles to improve distinguishing the bottles in combined therapy.

CONCLUSION

Instruction improves eyedrop administration in 18% of our patients. In combined therapy with several drugs new distinguishing marks are requested by the patients. To improve compliance combination preparations should be administered if available.

[Can the extent of glaucoma damage be quantified with laser polarimetry by in vivo measurement of retinal nerve fiber density? A clinical study]

Thirty-eight eyes of 38 glaucoma patients with a defined up-down asymmetry of visual field loss (VFL) were examined to ascertain whether there was corresponding up-down asymmetry of nerve fiber layer thickness (NFLT), calculated by laser polarimetry (LP). The correspondence was found to be closer for small up-down asymmetry of VFL then for medium or large up-down asymmetry. An approximately 6% greater NFLT in the lower than in the upper retinal half was revealed found by examination of 62 eyes of 62 normals. Considering this NFLT asymmetry in normals, there was a non-significant tendency towards correspondence between the up-down asymmetry of VFL and the up-down asymmetry of NFLT for the group of glaucoma patients with large up-down asymmetry of VFL. However, in about 40% of cases there was no such correspondence, so that staging of the glaucomatous disease has to be done by perimetry and is not possible by LP (software version 06/93).

Time of diagnosis, reoperations and long-term results of goniotomy in the treatment of primary congenital glaucoma: a clinical study

PURPOSE

The aim of our study was to get information about the development of visual acuity, visual field and cup-disc ratio of patients with primary congenital glaucoma after IOP-regulating goniotomy by means of a katamnestic inquiry. The preoperative conditions of IOP, corneal diameter and corneal opacity were related to postoperative findings of visual acuity, visual field and cup-disc ratio reported by the treating ophthalmologists.

METHODS

196 patients were contacted, who had a goniotomy in the period from 1965 to 1983 at the University Eye Hospital Würzburg. Out of the 92 returned replies, the address of the treating ophthalmologists could be ascertained from 77 patients. Sixty of the 77 patients fulfilled the inclusion criteria: (1) primary congenital glaucoma and (2) IOP-regulating goniotomy as last surgery.

RESULTS

I. In 76% of 106 eyes childhood glaucoma was diagnosed during the first year of life. II. In 72% of 60 eyes/patients with primary congenital glaucoma one goniotomy was sufficient to reach a normal IOP. In 18% a second and in 10% a third goniotomy was necessary, but without influence on the visual outcome. III. Even in the groups of eyes with a preoperative IOP of more than 40 mmHg, preoperative corneal diameter of more than 13 mm and preoperative severe corneal opacity more than 50% reached a visual acuity of 0.4-1.2 and more than 80% had a normal visual field. Only 9% of the eyes showed a cup-disc ratio of 0.6 or more.

CONCLUSIONS

In primary congenital glaucoma even eyes with high preoperative IOP, large corneal diameters and severe corneal edemas had a good prognosis of visual outcome after goniotomy.

[Perimetry with a glaucoma-specific test grid. A clinical study with the GG program]

The GG program pattern of the Humphrey Field Analyzer includes the 76 test points of the 30-2 program and an additional 52 test points in a glaucoma-specific distribution. In 18 test points in the nasal step area beyond 30 degrees the threshold is also determined. The findings obtained with the GG program and the 30-2 program were investigated by means of three questions: (1) Do the additional test points increase the sensitivity in ocular hypertension and glaucoma in stage I? For this purpose 41 eyes of 41 patients were examined. (2) Is the new grid useful for the determination of form and size of scotomas? For this purpose 46 eyes of 46 patients were examined. (3) What information is gained from a new asymmetry index, the glaucoma hemifield index (GHI), evaluated on the retinal threshold sensitivity of the GG program grid? To evaluate the information gained, the GHI of the test points in program 30-2 was compared to the GHI of the GG program in 11 eyes of 11 healthy persons, 21 eyes of 21 patients with ocular hypertension, and 32 eyes of 32 patients with primary open-angle glaucoma, stage I and II.

RESULTS

(1) In ocular hypertension and glaucoma stage I, the higher grid density of the GG program leads to a higher sensitivity in comparison to program 30-2. (2) In the 46 eyes with scotomas in stages II-IV, the condensed grid allowed better assessment of form and size of them. Ninety-one percent of the eyes with glaucoma stage II-IV showed nasal scotomas out of 30 degrees excentricity, which were now detected with the GG program. (3) The GHI of program 30-2 and the GG program showed no significant difference in retinal threshold sensitivity in glaucoma stage I. The asymmetry of the visual field loss in glaucoma stage II with localized scotomas can be detected significantly better with the GHI of the GG program. At the beginning of visual field loss with diffuse sensitivity loss, the grid density of program 30-2 seems to be sufficient. In stage II with localized scotomas, the higher grid density of the GG program yield more information for the detection of hemifield asymmetries. After examination with the 30-2 program it seems to be useful to examine the 52 additional test points and combine these two with the print-out from the GG program.

[Sensitivity and specificity of the Heidelberg retinal tomograph for imaging nerve fiber bundle defects in glaucoma patients with localized visual field defects. Clinical study]

In order to verify whether nerve fiber bundle defects can be detected by the confocal technique of the Heidelberg Retina Tomograph (HRT), we compared the localization of localized visual field defects with the localization of the expected corresponding nerve fiber bundle defect. We examined 105 patients: 49 with primary open-angle glaucoma (POAG), 26 with low-tension glaucoma (LTG) and 10 with ocular hypertension (OH), and as a control-group 20 healthy eyes. The glaucoma stage had been defined by examination of the central visual field with the Octopus Perimeter 201 program 31 or 32 and/or the Humphrey Perimeter GG program. In healthy eyes, eyes with OH and POAG stage I (n = 19), no nerve fiber bundle defect could be found. In stage II (n = 15) and stage III (n = 14) we found nerve fiber bundle defects in all patients with POAG and LTG (except for one patient with POAG stage III). In stage IV (n = 27) no localized nerve fiber bundle defects were detected in eyes with POAG, but in 4 of 7 patients with LTG, defects could be seen. In glaucoma stages II and III, nerve fiber bundle defects can be detected with the HRT. The control group shows, that the appearance of a nerve fiber bundle defect is no artifact caused by the HRT. However, examination of eyes with OH and POAG stage I also shows that this method is not sensitive enough to be useful for early diagnosis of glaucoma. Nevertheless, it may be possible to develop the confocal HRT method further as a nerve-fiber diagnostic method for glaucoma.

[High mean pallor value--a risk factor for deterioration of the visual field in glaucoma and ocular hypertension. A pilot study using the optic nerve head analyzer]

Does the disc parameter "mean pallor value" suggest a risk for further deterioration of visual field defects?

PATIENTS

In 10 patients with ocular hypertension and 23 patients with primary open-angle glaucoma (Octopus 201, Humphrey perimeter) disc pallor was calculated by double examinations with the ONHA in 1987-1988, and a long-term follow-up of the visual field was performed. In all patients we also acquired information about the IOP level and visual field during the observation time from the ophthalmologists. Only one eye per patient was evaluated after randomized selection.

RESULTS

In ocular hypertensive patients only 1 of 10 eyes showed deterioration of the visual field. In the glaucoma group 4 eyes out of 23 showed an increase in visual field loss. The eyes with a tendency to deteriorate had a higher mean pallor value compared with the mean value of the corresponding group [ocular hypertensives: 0.40 compared to 0.31 +/- 0.07 (0.02); POAG: 0.50 +/- 0.06 (0.03) compared to 0.33 +/- 0.08 (0.02); mean value +/- SE (SEM)]. The difference was statistically significant in the glaucoma group; Wilcoxon, Mann and Whitney U-test; P < 0.005.

CONCLUSIONS

Taking into consideration all risk factors, the mean pallor value might help additionally to prognosticate the risk of deterioration of the visual field as far as 5-year follow-up allows this preliminary conclusion. The pallor value alone is not suitable for the follow-up of glaucoma patients because of the influence of increasing lens opacities and changes in the video system of the ONHA over years.

The risk profile of the glaucomatous patient

This article briefly overviews risk factors involved in the multifactorial glaucomatous disease such as hypotension, preexisting field damage, location of scotomas, intraocular pressure, vasospasm, vasoactive agents, and less connective tissue of the optic disc. We summarize some of these risk factors in a formula allowing the calculation of a glaucoma progression risk index. This index helps to identify patients who are at risk for further visual field deterioration already at the time of the initial perimetric examination. Diagnostic and therapeutic aspects are highlighted.

[Measuring retinal nerve fiber density with laser polarimetry in patients with AIDS in comparison with health probands with reference to computer perimetry findings. A pilot study using the nerve fiber analyzer]

BACKGROUND

Several authors postulated a retinal nerve-fiber loss in HIV-infection because of functional alterations (reduced colour sensitivity, alterations in perimetry). This hypothesis has been reevaluated for the first time by means of direct in-vivo measurement of the retinal nerve-fiber-layer thickness by laser polarimetry using the Nerve-Fiber-Analyzer.

PATIENTS AND METHODS

Retinal nerve-fiber-layer thickness in 14 eyes of 7 patients has been compared to equally-sided eyes of equally-aged healthy controls. Visual fields showed a bilateral diffuse sensitivity reduction in 5 patients. Visual fields of 2 patients and all healthy controls were normal.

RESULTS

A significant difference in measurement values of nerve-fiber-layer thickness did not show between AIDS-patients and healthy controls. There was no correlation between visual field alterations and measurement values of nerve-fiber-layer thickness.

CONCLUSION

In AIDS patients, a retinal nerve-fiber loss corresponding to their visual-field alterations has not been found. However, these visual-field alterations may also be explained by central-nervous disorders, lens opacifications or neuro-retinal dysfunctions without nerve-fiber loss.

[Comparison of the measurement values of the laser tomography scanner and optic nerve head analyzer. A clinical study]

INTRODUCTION

With the Laser Tomographic Scanner (LTS) and the Optic Nerve Head Analyzer (ONHA) a quantifying investigation of the optic disc is possible. Both work with different principles: The LTS receives the information about the three dimensional structure with 32 transversal cuts, taken with the confocal principle, the ONHA with simultan stereopictures, taken from a different point of view.

PATIENTS AND METHODS

We examined 36 eyes (18 patients) with the LTS and the ONHA. The aim of the study is to examine, whether there are differences in the measurement values taken with the LTS and the ONHA investigating the same optic disc.

RESULTS

1. There are no significant differences in the measurement value of the area of the total disc and the horizontal and vertical diameter of the optic disc. 2. The measurement values of the area of the excavation and the quotient of the area of excavation to the area of the total disc are systematically greater in investigation with the LTS than in investigation with the ONHA. This is explained by the different definition of the boundary of the excavation. 3. There are significant differences in the measurement values of the volume of the excavation, the upper volume of the optic disc, and the maximum depth of the excavation. The measurement value of the volume of the excavation is systematically greater in investigation with the ONHA than in investigation with the LTS.

CONCLUSION

Measurement values of the parameters of the optic disc, which have the same definition in the LTS and the ONHA--such as the area of the total disc and the horizontal and vertical diameter of the optic disc--show no significant differences. Thus these parameters are comparable in the LTS and the ONHA.

[Sarcoidosis of the optic nerve]

BACKGROUND

Rarely an affection of the optic nerve is seen as the initial or only manifestation of sarcoidosis. Therefore the disease is often diagnosed late. The aim of systemic corticosteroid therapy is to prevent progression though it cannot yield a cure.

PATIENT AND METHOD

Despite a high-dose corticosteroid therapy in suspected optic neuritis a 25-year-old woman developed unilateral amaurosis. When visual acuity continuously decreased in the second eye a computerized tomography was performed, which suggested a tumor of the optic nerve. A biopsy of this lesion lead to the diagnosis of Boeck's disease. A long-term corticosteroid therapy was initiated. Over the following 9-year period corticosteroids were dosed according to the results of regular clinical and perimetrical examinations (200 examinations with Octopus-Perimeter 201, program G1). In case of deterioration of the visual field higher oral doses were applied. When no improvement was achieved by this, corticosteroids were given intrathecally. Under this therapeutic regime no systemic side effects were seen.

CONCLUSION

In unilateral visual loss Boeck's disease should be considered as a rare etiology. In case of clear optical media frequent computerized perimetry allows the neurologist to adjust the dosage of cortisone and minimize its side effects.

Efficacy of apraclonidine ophthalmic solution (Iopidine) in presumed silicon oil-induced glaucoma and primary open-angle glaucoma

BACKGROUND

This pilot study evaluated the acute effects of topical ocular apraclonidine 1% (Iopidine) in 10 patients with presumed silicone oil-induced secondary glaucoma (SOIG) and in 10 patients with high-pressure primary open-angle glaucoma (POAG) despite maximum tolerated medical therapy.

METHODS

Intraocular pressure (IOP) measurements were carried out before and 1, 2 and 3 h after a single drop of apraclonidine.

RESULTS

Patients with SIOG presented with a mean IOP of 30.0 +/- 2.8 mmHg, which was reduced to 21.7 +/- 2.9 mmHg (P < 0.001) after 1 h, to 20.4 +/- 2.3 mmHg (P < 0.001) after 2 h and to 20.0 +/- 2.5 mmHg (P < 0.001) after 3 h. In the POAG group, IOP was reduced from 25.9 +/- 1.9 mmHg before treatment to 18.9 +/- 1.4 mmHg after 1 h (P < 0.001), 17.7 +/- 1.2 mmHg after 2 h (P < 0.001) and 16.9 +/- 0.9 mmHg after 3 h (P < 0.001). There were no significant changes in blood pressure or pulse rate.

CONCLUSION

This study confirmed the activity of apraclonidine as an IOP suppressant.

[Effect of systolic blood pressure on the location of visual field defects in upper and lower visual half-fields in patients with chronic simple glaucoma]

In earlier studies we found that visual field defects occur more frequently in the lower half of the visual field and that low systolic blood pressure occurs more frequently in low-tension glaucoma (stage II) compared to primary open-angle glaucoma (POAG) (stage II). We wanted to find out whether visual field defects in the lower half of the visual field point to insufficient perfusion of the optic nerve head due to low blood pressure. We therefore examined the visual fields of 153 eyes of 153 patients with POAG and regulated IOP with program 31 or 33 of the Octopus perimeter 201. With program Delta the loss per test point in the upper and lower hemifield was calculated. The mean systolic blood pressure was calculated for each patient from the blood pressure recordings during the observation time and over a long-term follow-up period (3-19 visual field examinations during a period of 1-8 years). With the Delta program we decided case by case whether the visual field showed a tendency to deteriorate or not. An asymmetry in the mean loss per test point between the two visual hemifields in a relation of 2:1 or more was found in 71 eyes out of 153. In the upper hemifield 50 out of 71 patients had two times greater loss per test point than in the lower hemifield. These patients showed a mean systolic blood pressure of 158 +/- 37 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)

[Significance of raised intraocular pressure in glaucomatous visual field defects. A clinical study]

1. 300 eyes of 300 patients with primary open angle glaucoma (POAG) were examined with program 31 of the Octopus perimeter 201 and the amount of visual field loss (total loss) was quantified with program Delta. The total loss was correlated to the height of the maximum intraocular pressure (IOP max). There was no correlation in the interindividual comparison between IOP max and total loss. This shows the influence of IOP independent risk factors in POAG. 2. In an intraindividual comparison 108 eyes of 54 patients with POAG were examined under the question: Have eyes with the four times higher amount of visual field loss in one eye compared to the other, a significant higher IOP max in the eye with the more severe damage. The intraindividual comparison excludes cardiovascular risk factors, because they affect both eyes. So the difference in IOP can show better the damaging influence of IOP: Eyes with the higher amount of visual field loss showed a significant higher IOP max. This shows the impact of the elevated IOP is a risk factor in POAG. 3. 300 eyes of 300 patients with POAG were further examined under the question, whether the relation between the mean loss per test point in the upper half of the visual field in comparison to the mean loss per test point in the lower half of the visual field is different at different IOP max levels. 162 eyes with an IOP max of less than 30 mmHg and 75 eyes with an IOP max of 30 up to 36 mmHg and 63 eyes with IOP max of 37 and more mmHg were evaluated and the 3 groups were compared. With an increasing height of IOP max an increasing equal distribution of the visual field loss in upper and lower visual field half was found. High IOP results in a diffuse nerve fibre damage and more IOP-unindependent risk factors result in localized visual field damage. So there are at least two pathomechanisms in POAG.

[Pallor of the optic papilla--an early sign of glaucoma. A clinical controlled study of optic disk pallor and papillar cupping in glaucoma simplex, ocular hypertension and normal eyes with the optic nerve head analyzer]

Double examinations of 99 eyes (34 healthy, 12 with ocular hypertension, 53 with primary open-angle glaucoma) were performed with the Optic Nerve Head Analyzer to evaluate whether an increase in disk pallor or in the cup-disk ratio (CDR) is the earlier sign of glaucoma. In eyes with primary open-angle glaucoma the CDR and the mean optic disk pallor value are significantly higher than in healthy eyes. There is no significant difference in the CDR of patients with ocular hypertension as compared to normals. However, the mean pallor value is significantly higher in eyes with ocular hypertension than in healthy eyes. Therefore, an increase in pallor may precede a significant increase in the CDR or detectable visual field defects.

Optic nerve head measurements: the optic nerve head analyzer--its advantages and its limitations

The Optic Nerve Head Analyzer (ONHA) calculates by means of computer-assisted analysis of stereo images different parameters of the optic disc: disc diameter, disc size, cup/disc ratio (CDR), neuroretinal rim area, and excavation volume for the disc quadrants and for the total disc. To obtain first indications of the clinical value of ONHA measurements for diagnosis and follow-up in glaucoma we examined the reproducibility of measurement results for different diseases. Furthermore, we studied the mean values of the different disc parameters in healthy eyes. It was investigated: 1) whether the reproducibility is different in the different disc parameters; 2) whether the reproducibility in different eye diseases is different as compared to healthy eyes; 3) by which criteria the reproducibility is influenced; 4) whether there is a correlation between disc size and size of rim area. The reproducibility was studied in 178 eyes of 178 patients, who were all examined twice with the ONHA. The mean difference between the results of first and second measurement was calculated for the different disc parameters. Differences were found in the reproducibility of the parameters: e.g., the mean difference between first and second measurement was 1.8 percent for the disc size, and 5.6 percent for the neuroretinal rim area. For the disc quadrants, the reproducibility of values was worse than for the total disc. No marked differences of reproducibility of disc parameters were found for different diseases. Reproducibility depends, for instance, upon correct determination of the disc margin. In healthy eyes, a significant correlation was found between rim area and disc size: larger discs have a larger neuroretinal rim area than smaller discs. Thus, the rim areas of different eyes are only comparable for equally sized discs. Relative values, as for instance, cup/disc ratio, or the quotient of rim area and disc size, are therefore better suited for comparison of different eyes than absolute values. The recent developments in automatic disc analysis equipment and the clinical relevance of the results for diagnosis and follow-up in glaucoma are discussed.

Long-term studies of visual field changes by means of computerized perimetry (Octopus 201) in eyes with glaucomatous field defects after normalization of the intra-ocular pressure

126 eyes with open-angle glaucoma and defects of the visual field were studied over five years (+/-1.3) by repeated perimetries with Octopus Perimeter, Program 31, after the IOP had been normalized from 26.49 mm Hg to 19 mm Hg. All patients had suffered visual field defects in the period with increased pressure preceding our study and had many perimetric examinations before. The aim of the study was to check the behaviour of the visual field defects after pressure normalization. For evaluation of the visual fields, the upper most line of the test-points and the 6 test-points surrounding the blind spot were disregarded. The evaluation of each field and the comparison with preceding fields (no change, better, or worse) were done by the symmetry test of Bowker instead of the Delta Program, taking into account each of the 61 test-points with a significance level of 5%. In each patient the eye with the heavier field loss was evaluated.

RESULTS

67% of all eyes had no change during the observation time, 12% became better, and 21% worse. Improvement of the visual fields occurred even in old age: 10% became better in the age-group over 70 years. The total loss decreased in the 15 eyes which improved by 269 dB. In eyes which deteriorated, the total loss increased by 282 dB. The good news of this study is that normalization of IOP can stop the further decay of the visual-field in 67% and an improvement of the field loss is possible even in old age of with heavy field loss.(ABSTRACT TRUNCATED AT 250 WORDS)

[Optic papilla parameters in healthy subjects--quantified with the optic nerve head analyzer]

The cup-disk ratio (CDR), the size of the neuroretinal rim area as well as the other disk parameters investigated with the Optic Nerve Head Analyzer (ONHA) were measured in double examinations of 32 healthy eyes in 32 patients. Thus, "normal" values were determined for the various disk parameters. A new method is presented for calculating one average pallor value for the disk. The mean value for disk pallor in healthy eyes is determined. Examination of the CDR in the quadrants of the disk reveals significant differences. According to the results of a multi-regressional analysis of the various disk parameters, the size of the neuroretinal rim area in healthy eyes is influenced by the size of the disk, the disk volume and the elevation volume. The correlation between the size of the neuroretinal rim area and the size of the disk reveals a significant interdependence: a larger disk also has a greater neuroretinal rim area as compared to a smaller disk. This means that sizes of neuroretinal rim areas of different disk should only be compared when the disks are the same size. Relative values, such as the CDR or the ratio between the size of the neuroretinal rim area and disk size (rim area/disk area), are therefore better suited for comparison.

[Quantification and progression of the visual field defect in glaucoma without hypertension, glaucoma simplex and pigmentary glaucoma. A clinical study with the Delta Program of the 201 Octopus perimeter]

Visual field defects of stages I-IV, in 451 eyes of 451 glaucoma patients, were examined with the Octopus 201 perimeter: 83 patients with low-tension glaucoma (LTG), 316 patients with primary open-angle glaucoma (POAG), and 52 patients with pigmentary glaucoma (PG). Program 31 or 33 was used, with an eccentricity range of up to 30 degrees, 73 test points, and a 6 degrees grid. The mean total field loss (TL) as well as the mean loss per test point (TL/TP) in the 30 degrees field, in the field quadrants, and in the eccentricity ranges from 0-10 degrees, 10-20 degrees, and 20-30 degrees were calculated for each patient with Program Delta. In addition, for each visual field the quotient of total loss and of the number of disturbed test points was calculated, providing a measurement of the mean depth of the field defects. For definition and comparison of visual fields in the different glaucomas at identical stages of the disease according to the amount of TL, the 3 patient groups were subdivided into 4 stages of sensitivity loss: Stage 1: TL less than or equal to 100 dB; Stage 2: TL 101-400 dB; Stage 3: TL 401-800 dB; Stage 4: 801-1600 dB. The results of a comparison of eyes with LTG, POAG, and PG at the same stage of disease were as follows: I. Location of scotomas: 1. Defects more frequent in the lower field in LTG as compared to POAG in stage 2. 2. Defects more frequent in the upper than in the lower field in POAG. 3. Almost equal number of defects in the upper and lower halves in PG. 4. In all 3 glaucoma types the defects are more frequently found in the nasal than in the temporal half of the visual field. 5. In LTG and POAG of all stages the defects are most frequently found in the upper nasal and most seldom in the lower temporal quadrant. 6. In all glaucoma types the defects occur on average most frequently between 10 degrees and 20 degrees of eccentricity. 7. With increasing IOP in POAG the scotomas tend to be equally distributed in the upper and lower quadrants. II. Depth of scotomas: 1. Scotomas are deepest in LTG; they are less deep in POAG, and least deep in PG. 2. In PG the mean scotoma depth depends significantly on maximum IOP.(ABSTRACT TRUNCATED AT 400 WORDS)

Alterations of carboxypeptidases N activities in patients with thyroid dysfunction

Serum carboxypeptidases N (EC. 3.4.17.3) were determined spectrophotometrically in 87 patients with disturbances of thyroid function and in 131 euthyroid individuals, including 33 women taking estrogens for contraception. Carboxypeptidases N (CN) can be subdivided into CN1 and CN2, according to variable substrate affinity. In addition, measurements of blood pressure and in vitro tests of thyroid function were performed. In euthyroid controls, CN1 was negatively correlated with age. No significant differences between CN1 and CN2 have been observed with regard to sex. In patients with hyperthyroidism, the mean values of both enzymes were elevated, but this tendency proved to be significant only for CN2. In hypothyroid patients CN1 and CN2 levels were normal. Elevations of CN1 and CN2 in the hyperthyroid state seem not to be related to underlying immunological processes but to the thyroid hormone excess itself. In euthyroid women taking estrogens for contraception CN2 was also elevated.

[Site and depth of glaucomatous visual field defects in relation to the size of the neuroretinal edge zone of the optic disk in glaucoma without hypertension, simple glaucoma, pigmentary glaucoma. A clinical study with the Octopus perimeter 201 and the optic nerve head analyzer]

The size of the neuroretinal rim area of the disk was measured with the Optic Nerve Head Analyzer in 57 eyes of 57 patients with low-tension glaucoma (LTG), glaucoma simplex (POAG), and pigmentary glaucoma. The visual fields were examined with Program 33 or 31 (30 degrees eccentricity, 6 degrees grid) of the Octopus 201 Perimeter. The mean sensitivity loss per test point in the central field, in the field quadrants, and in the ranges from 0 degrees-10 degrees, 10 degrees-20 degrees, and 20 degrees-30 degrees were calculated with the Delta program. In addition, the mean loss per disturbed point, which gives the mean depth of scotomata, was calculated. In LTG a larger vertical cup/disk ratio (CDR) was found than in POAG for the same amount of total loss. The comparison of eyes with neuroretinal rim areas of equal size revealed that in contrast to POAG and pigmentary glaucoma, eyes with LTG had a smaller mean sensitivity loss; deeper, more localized scotomata; more visual field defects in the lower field in the initial stages; more scotomata in the area up to 20 degrees. The differences between glaucoma with and without high intraocular pressure were found to be most pronounced in the initial stages of the disease. These differences appear to be caused by the varying amounts of vascular pathogenesis involved. Therefore, at least two pathomechanisms have to be considered in glaucoma.

[Glaucoma without ocular hypertension. A clinical study]

One hundred eighty-four glaucomatous eyes (125 patients) with visual field defects of Stage I and II in the central visual field were examined with the Octopus perimeter 201, Program 31 or 33, and were divided into 3 groups according to maximum intraocular pressures: (1) low-tension glaucoma (21 mm Hg), (2) glaucoma simplex (22-29 mm Hg), (3) glaucoma simplex (30-39 mm Hg). In these three groups of glaucomatous eyes the cupping of the optic disk, vision and blood pressure were examined and a further check for cardiovascular risk factors was carried out by the internist. All three groups proved to have an equally high incidence of cardiac insufficiency, abnormal EKG changes and diabetes. However, a low systolic blood pressure was found to be the risk factor more often in patients with low-tension glaucoma than with glaucoma simplex. Furthermore, intraocular pressures in the low-tension glaucoma group were higher than those in the normal population. The occurrence of cupping of the optic disk, which is not present with purely vascular optic nerve diseases, and the location of visual field defects in low-tension glaucoma, which is similar to that in glaucoma simplex but different from vascular diseases, as well as the increased diurnal tension variations of diurnal tension curves compared to the normal population are all factors which indicate that low-tension glaucoma is not a purely vascular optic nerve disease, and that pressure-lowering therapy is necessary.(ABSTRACT TRUNCATED AT 250 WORDS)