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Biomedical subjects

J B Jonas

Publications and source records attributed to J B Jonas.

At least 163 records · Page 9Linked to original sources
PubMed1996

Optic disc shape in glaucoma.

BACKGROUND: This study was performed to evaluate the shape of the optic disc in glaucoma. METHODS: We examined morphometrically color stereo optic disc photographs of patients with primary open-angle glaucoma (n = 804), secondary open-angle glaucoma (n = 130), normal-pressure glaucoma (n = 75), and high myopia combined with open-angle glaucoma (n = 33), visually normal subjects (n = 421), and nonglaucomatous subjects with high myopia (n = 36). The optic disc form was determined by the ratio of the minimal to the maximal disc diameter, the ratio of the horizontal to the vertical disc diameter, the angle between the maximal disc diameter and the horizontal, and a calculated form factor. RESULTS: In the normal eyes, the ratios and the form factor varied interindividually by less than 1:2. For a myopic refractive error of less than -8 D, the normal eyes and the glaucoma eyes did not differ significantly (P > 0.20) in their slightly vertically oval optic disc shape. Within the primary open-angle glaucoma group, the optic disc shape was not correlated with the neuroretinal rim area and the mean perimetric defect, either interindividually or in an intraindividual bilateral comparison. In the highly myopic group, the optic disc was significantly more ovally configurated, more obliquely orientated, and larger than in any other group. CONCLUSIONS: In contrast to the size of the optic nerve head, the shape of the optic disc does not show pronounced interindividual variability in eyes with a myopic refractive error of less than -8 D. With highly myopic eyes excluded, the optic disc shape as single variable is not markedly important for pathogenesis, early diagnosis and differential diagnosis of the glaucomas.

Diagnosis, Differential↗
PubMed1996

Retinal pigment epithelial cell count, distribution, and correlations in normal human eyes.

PURPOSE: To determine the number of the retinal pigment epithelial cells, their regional distribution, and correlations with general variables in normal human eyes. METHODS: We examined 53 normal human donor eyes from individuals with a mean age of 58.6 +/- 18.8 years and an axial length of less than 27 mm. After opening the globes by a 16-mm corneoscleral trephination, up to 25 biopsy specimens of the retina and retinal pigment epithelium were obtained in four meridians. The retinal pigment epithelial cells and the retinal photoreceptors were counted on photographs taken from the apical retinal pigment epithelial surface and the inner photoreceptor segments. RESULTS: Total number of the retinal pigment epithelial cells was 3,556,290 +/- 490,700 (mean +/- S.D.; range, 2,130,500 to 4,653,200), and it was positively correlated with the number of rods and cones, the total area of the retina, the optic disk size, and the retinal pigment epithelial cell density but was independent of gender. The retinal pigment epithelial cell density decreased significantly (P < .001) from the fovea (4,220 +/- 727 cells/mm2) to the midperiphery (3,002 +/- 460 cells/mm2) and to the outer peripheral fundus regions (1,600 +/- 411 cells/mm2). In the retinal periphery, the retinal pigment epithelial cell density was the highest (P < .01) in the nasal fundus region compared with any other fundus quadrant. The retinal pigment epithelial cell density decreased by about 0.3% per year with increasing age. CONCLUSIONS: These data on the quantitative anatomy of the retinal pigment epithelium may be important for physiology and pathophysiology of the visual process, especially in evaluating the effects of aging.

Adolescent↗
PubMed1996

Retinal detachments by squash ball accidents.

PURPOSE: To evaluate the characteristics of retinal detachments caused by squash ball accidents. METHODS: Twenty-six patients had a retinal detachment after a squash ball hit their eyes. RESULTS: Characteristics of the 26 eyes with retinal detachment were large retinal tears parallel to the corneoscleral limbus located close to the ora serrata usually in the temporal superior fundus quadrant (in 14 [54%] of the 26 eyes) and in the temporal inferior quadrant (in seven eyes [27%]); primarily intact vitreous with a traumatic avulsion of the vitreous base in approximately one half the patients; relatively slow progression of the retinal detachment; and additional damage to the choroid and retinal pigment epithelium in the posterior fundus. The patients were young and did not have severe myopia. Reattachment of the retina was achieved in 22 (85%) of the 26 patients. In 11 patients (42%), visual acuity outcome was 20/40 or better with best correction. CONCLUSIONS: Retinal detachments after squash ball accidents show different characteristics with worse prognosis than do ordinary rhegmatogenous detachments. Protective eyewear should be worn when playing squash.

Adolescent↗
PubMed1996

Ochrobactrum anthropi endophthalmitis after uncomplicated cataract surgery.

PURPOSE: To treat a case of Ochrobactrum anthropi endophthalmitis after uneventful cataract surgery. METHODS: A 66-year-old patient in good general health underwent uncomplicated cataract surgery in his right eye. Seven weeks later, pars plana vitrectomy with removal of the intraocular lens became necessary because of progressive low-grade endophthalmitis resistant to topical and systemic erythromycin, cephalosporins, aminoglycosides, and colistin. RESULTS: Microbiologic examination of the vitreous biopsy, capsule, and anterior chamber fluid disclosed O. anthropi, a nonfermentative gram-negative bacillus sensitive to imipenem, amikacin, ciprofloxacin, and vancomycin. CONCLUSION: Ochrobactrum anthropi and its natural resistance against many antibiotics should be considered in the treatment of low-grade endophthalmitis after uneventful cataract surgery.

Aged↗
PubMed1996

Echographic measurement of optic nerve thickness correlated with neuroretinal rim area and visual field defect in glaucoma.

PURPOSE: To determine whether echographic measurements of the pial diameter of the optic nerve are significantly correlated with glaucomatous changes of the optic disk and retinal nerve fiber layer. METHODS: In 31 patients with primary open-angle glaucoma and 16 normal control subjects, optic nerve thickness was determined by measuring the maximal pial diameter of the optic nerve using standardized A-scan echography. The optic disks were morphometrically examined using color stereo photographs, and the retinal nerve fiber layer was assessed using wide-angle red-free fundus photographs. RESULTS: Optic nerve thickness as measured echographically decreased significantly (P < .001) with decreasing neuroretinal rim area, diminishing visibility of the retinal nerve fiber layer, narrowing of the retinal arterioles, enlarging parapapillary atrophy, and increasing mean visual field defect. In an intraindividual bilateral comparison, side differences in the optic nerve thickness were significantly correlated with side differences in neuroretinal rim area (P < .0001), diameter of retinal arterioles (P = .003), and visual field defect (P < .0001). In the differentiation of normal and glaucomatous eyes, sensitivity and specificity were higher for echographic measurements of the optic nerve thickness than for parapapillary atrophy and diameter of retinal arterioles but worse than for determination of the neuroretinal rim area. CONCLUSIONS: Echographic measurements of optic nerve thickness are significantly correlated with glaucomatous changes of the optic disk and retinal nerve fiber layer. In patients with opaque media, echographic measurement of optic nerve thickness may be helpful in distinguishing among normal eyes, eyes with medium advanced glaucoma, and eyes with markedly progressed glaucoma.

Adult↗
PubMed1996

Comparison between tomographic scanning evaluation and photographic measurement of the neuroretinal rim.

PURPOSE: To compare laser tomographic scanning evaluation with photographic measurement of size and shape of the neuroretinal rim. METHODS: For 25 normal eyes and 32 glaucomatous eyes, the optic disks were examined with the Heidelberg Retina Tomograph (software version 1.11) for confocal laser tomographic scanning evaluation, and color stereoscopic optic disk photographs for planimetric measurements. Area and width of the neuroretinal rim were determined as percentages of the disk area and diameter, respectively. RESULTS: For the normal and glaucomatous eyes, the tomographic results compared with the photographic measurements disclosed significantly larger values for the relative width and relative area of the neuroretinal rim. The differences between both methods were most marked in the nasal part of the optic disk and least marked in the temporal disk region. The relative differences increased significantly (P < .05) with increasing degree of glaucomatous optic nerve damage. CONCLUSIONS: In normal and glaucomatous eyes, the Heidelberg Retina Tomograph determines the neuroretinal rim, expressed as percentage of optic disk measurements, to be significantly larger than when the rim is evaluated on optic disk photographs. Because parts of the central retinal vessel trunk are defined as neuroretinal rim in the algorithm of the Heidelberg Retina Tomograph, the differences between Heidelberg Retina Tomograph measurements and photographic determinations of the rim are largest in the nasal disk region and smallest in the temporal disk area. The neuroretinal rim shape and neuroretinal rim area differ appreciably between the two methods. These differences increase with increasing degree of glaucomatous optic nerve damage.

Adolescent↗
PubMed1996

Interobserver variation in the measurements of peripapillary atrophy in glaucoma.

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.

Adult↗
PubMed1996

[Sensory physiology and biomorphology of the optic papilla: analysis of correlation in normal persons].

BACKGROUND: The aim of the present study was to investigate whether the morphological variability of the optic disc has an influence on sensory test procedures. PATIENTS AND METHODS: In 52 eyes of 52 normal persons psychophysical (perimetry, color vision, contrast sensitivity) and electrophysiological (pattern-ERG and pattern-VEP) tests and planimetric papillometry were performed. A correlation analysis was made between sensory tests and area of optic disc (1.79 to 5.2 mm2) and neuroretinal rim. RESULTS: There was no significant correlation between perimetry, color vision, pattern-ERG, pattern-VEP, spatio-temporal and temporal contrast sensitivity on the one hand and optic disc area or neuroretinal rim area on the other. CONCLUSION: Results of psychophysical and electrophysiological tests do not have to be corrected with respect to the neuroretinal rim area.

Adult↗
PubMed1996

[Band-like corneal degeneration as the initial sign of sarcoidosis].

BACKGROUND: Sarcoidosis is a multisystem granulomatous disease of unknown etiology. Ocular involvement has been reported in about 25% of patients (1). Band keratopathy is rare in sarcoidosis. PATIENT: A 31 year-old clerk presented to our clinic with a 10 months' history of foreign body sensation OU. Visual acuity was OD1.2, OS 1.0. Intraocular pressure was 10 mm Hg OU. We found a moderate band keratopathy OU (Fig. 1a, 1b). The rest of the ocular exam was unremarkable. 10 months before, the patient had experienced symmetrical swelling of his large joints and his creatinine and calcium levels had been elevated at that time. Therefore, we referred the patient to the internist to rule out primary hyperparathyroidism (2). The differential diagnosis included myeloma, paraneoplasia and sarcoidosis (3). The general medical examination was unremarkable. Calcium (2.5 mmol/l), creatinine (2.0 mg/dl) and ACE-levels (177 U/ml) were elevated, parathormone (< 1.4 pg/ml) was low. The chest x-ray showed reticular, small-nodular changes of both lungs. Pulmonary function tests and the bronchial mucosa were normal. The CD4/CD8-ratio was markedly elevated. Ultrasonography of the kidneys suggested nephrocalcinosis. This was confirmed by kidney biopsy. Histologic findings were consistent with the diagnosis of sarcoidosis. After initial symptomatic reduction of calcium levels by forced diuresis, calcium and creatinine levels were lowered by administration of 60 mg prednisolone daily. Six months after presenting to our clinic the patient is well on low-dose steroids and his calcium levels are normal. DISCUSSION: Primary hyperthyroidism was ruled out by low PTH-levels. Because of clinical, serologic and radiologic findings suggestive of sarcoidosis, bronchoscopy with bronchoalveolar lavage was performed. Since the CD 4/CD 8-ratio was increased, a kidney biopsy was performed which confirmed the diagnosis.

Adult↗
PubMed1995

Determination of the neuroretinal rim area using the horizontal and vertical disc and cup diameters.

BACKGROUND: This study evaluated whether the neuroretinal rim area can be calculated on the basis of the horizontal and vertical diameters of the optic disc and cup applying the formula of an ellipse. METHODS: Color stereo optic disc photographs of 587 normal subjects and 1193 patients with glaucoma were morphometrically examined. In a first method, the areas of the optic disc and cup were planimetrically measured and the area of the neuroretinal rim was determined as optic disc area minus cup area. In a second method, the optic disc and cup were assumed to have an elliptical shape. Their areas were calculated by applying the formula of an ellipse, taking into account their horizontal and vertical diameters. As in the first method, the rim area was then determined as disc area minus cup area. RESULTS: The values of the neuroretinal rim area as measured using the first method differed by 0.05 +/- 0.05 mm2 from the values as calculated by the second method. The average error was 2.8 +/- 2.9% for the normal group and 8.2 +/- 20.8% for the glaucoma patients. It increased with decreasing neuroretinal rim area and increasing mean visual field defect. CONCLUSIONS: For clinical purposes, the neuroretinal rim area can be determined on the basis of the horizontal and vertical diameters of the optic disc and cup. The horizontal and vertical disc and cup diameters being determinable upon ophthalmoscopy, this finding is important for the direct measurement of optic disc morphology during any ophthalmoscopic examination.

Adolescent↗
PubMed1995

Optic nerve fiber count and diameter of the retrobulbar optic nerve in normal and glaucomatous eyes.

BACKGROUND: The caliber of the retrobulbar optic nerve and the count of optic nerve fibers vary considerably in normals. The diameter of the retrobulbar optic nerve also decreases with optic nerve atrophy. This study aimed to determine the relationship between the caliber of the optic nerve and the optic nerve fiber count. METHODS: We counted the optic nerve fibers and measured the diameter of histological cross sections of the optic nerve for 56 normal subjects and 23 patients with absolute glaucoma. RESULTS: The optic nerve fiber count increased significantly (P < 0.0001) by 777,000 fibers for every millimeter increase in retrobulbar optic nerve diameter, starting at a baseline diameter of 1.89 mm. CONCLUSION: Using this linear regression equation, the optic nerve fiber count can be estimated in routine histology by measuring the optic nerve diameter. Taking into account a fixation-induced tissue shrinkage, this method may also give some indication of the optic nerve fiber count intravitally, when, for eyes with opaque optic media, the diameter of the retrobulbar optic nerve has been measured by imaging techniques. Greater retrobulbar optic nerve caliber may indicate greater structural reserve capacity.

Adult↗
PubMed1995

Optic disc morphology in diabetes mellitus.

BACKGROUND: Diabetes mellitus is a systemic disease affecting multiple tissues throughout the body. This study was performed to evaluate intravitally the diabetic changes of the optic disc. METHODS: Color photographs of 115 eyes with varying severity of diabetic retinopathy and of 29 normal eyes were morphometrically examined. RESULTS: We found that the size and shape of the optic disc, the neuroretinal rim and the parapapillary atrophy did not differ significantly between the diabetic eyes and the normal eyes. These variables were independent of the degree of diabetic retinopathy. There was a tendency toward decreased visibility of the retinal nerve fiber layer and increased optic disc pallor in the diabetic eyes. CONCLUSION: The results indicate that the area and form of the optic disc, the neuroretinal rim and parapapillary atrophy are not altered by diabetes mellitus. This is important for the diagnosis of glaucoma in diabetic patients, since glaucoma leads to a decrease of rim area and an enlargement of parapapillary atrophy. The reduced visibility of the retinal nerve fiber layer, the increased optic disc pallor and the unchanged size of the neuroretinal rim and parapapillary atrophy suggest that diabetes mellitus may be associated with nonglaucomatous optic nerve atrophy.

Diabetes Mellitus↗
PubMed1995

Pressure-dependent changes of the optic disk in primary open-angle glaucoma.

PURPOSE: This study was performed to differentiate glaucomatous changes of the optic disk that may be caused by increased intraocular pressure from those that may be pressure independent. METHODS: For 357 patients with primary open-angle glaucoma, the optic disk was morphometrically analyzed, and the intraocular pressure was measured in 24-hour profiles. RESULTS: By performing an intraindividual bilateral comparison, the differences in the maximal intraocular pressure values of the right eye minus the left eye of the same individual were significantly correlated with the differences in neuroretinal rim area and mean perimetric defect of the right eye minus the left eye. No significant correlations were found for the parapapillary atrophy. CONCLUSIONS: The results indicate that the eye with the higher pressure compared with the fellow eye with the lower pressure showed neither a significantly larger nor smaller parapapillary atrophy, which suggests that the papapapillary atrophy, compared with the neuroretinal rim area and the visual field defect, is less dependent or almost independent of an increased intraocular pressure.

Adolescent↗
PubMed1995

Atypical Peters' anomaly associated with partial trisomy 5p.

PURPOSE: We examined a child who had atypical Peters' anomaly and partial trisomy 5p. METHODS: An 11-week-old female infant with multiple developmental malformations and a partial trisomy 5p had bilateral corneal opacities extending from the center of the cornea to the paralimbal region and bilateral iridocorneal adhesions in the areas of the corneal opacities. RESULTS: In addition to association with several other chromosomal disorders, Peters' anomaly may be associated with partial trisomy 5p. CONCLUSIONS: Since partial trisomy 5p can be diagnosed by genetic evaluation, a chromosomal analysis should be performed for children with Peters' anomaly.

Abnormalities, Multiple↗
PubMed1995

Large optic discs in large eyes, small optic discs in small eyes.

The optic disc area, varying interindividually by a factor of 1:7, is correlated with the count of the retinal ganglion cell axons and photoreceptors. This study evaluated whether the variations in the disc size are additionally correlated with those of the coronary diameters of the globe. Fifty-three normal human donor eyes with a mean age of 54.2 +/- 19.6 years were included in the study. After performing a 16-mm corneoscleral trephination, the globes were fixed and the horizontal and vertical diameters of the globes were measured. We cut the globes into meridional slices sticking together at the posterior fundus region. The areas of the whole retina and the optic disc were planimetrically evaluated on photographs with a millimeter scale aligned. We found that the horizontal and vertical diameters of the globe were correlated with the optic disc size and the retinal surface area. Eyes with long horizontal and vertical diameters had a larger optic disc and a larger retinal surface area than eyes with short diameters. The results suggest the combination of large optic discs in large eyes and of small optic discs in small eyes. Taking into account the relatively low correlation coefficients of 0.3 and 0.4, the study also suggests the existence of other not-evaluated factors influencing the occurrence of large optic discs. The results go along with the reported association between a large optic disc area and a large cornea size.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Retinal photoreceptor density decreases with age.

PURPOSE: To evaluate the effect of age on the density of retinal photoreceptors in humans. METHODS: Fifty-five normal eyes from human donors, with a mean age of 58.7 +/- 19.1 years and an axial length of less than 27 mm, were examined. After opening of the globes by a 16-mm corneoscleral trephination, 25 retinal tissue samples were obtained in four meridians. The photoreceptors were counted on photographs taken from the photoreceptor inner segments after sonographic removal of the outer segments. The cones in the foveal center could not be evaluated. RESULTS: Outside the foveal center, the photoreceptor density decreased significantly with increasing age. In absolute and relative terms, the decline was more marked for the rods (mean rod loss, 236 +/- 63 cells or 0.37% +/- 0.10%/mm2 and year of a mean density of 62.987 rods/mm2) than for the cones (mean cone loss, 5.90 +/- 0.68 cells or 0.18% +/- 0.02%/mm2 and year of a mean density of 3320 +/- 578 cones/mm2). For both cones and rods, the cell loss was more marked at an eccentricity of approximately 5-8 mm than in the retinal periphery at an eccentricity of 14 to 20 mm. There were no significant differences between the superior, inferior, temporal, or nasal meridian nor between women and men. CONCLUSIONS: The photoreceptors decrease in density with increasing age. The annual cell loss of approximately 0.2% to 0.4% is similar to the age-related loss of retinal ganglion cells and pigment epithelium cells. The decline in photoreceptor count affects more rods than cones. It does not prefer special age groups. It is more pronounced at an eccentricity of 5 to 8 mm than in the retinal periphery at an eccentricity of more than 14 mm. It may be important for an age-related decrease in visual functions and for diseases affecting the photoreceptors in elderly patients.

Adolescent↗