[Accuracy of IOL power prediction in cataract surgery after penetrating keratoplasty--retrospective study of 72 eyes]. / Treffsicherheit der Kunstlinsenberechnung bei Katarakt-Operation nach perforierender Keratoplastik--retrospektive Studie an 72 Augen.

BACKGROUND: In concomitant cataract surgery and penetrating keratoplasty (PKP), the sequential procedure is supposed to have a higher accuracy in calculation of the intraocular lens (IOL) power compared to the triple procedure. The purpose of this study was to evaluate the refractive results of cataract surgery in patients after PKP. MATERIALS AND METHODS: Our retrospective study included 72 operations on 65 patients. In 35 eyes (group 1, G 1), all corneal sutures had been removed before cataract surgery (median time interval after PKP 3.1 years), while in 37 eyes (group 2, G 2) corneal sutures were in place but removed intra- or postoperatively (median time interval after PKP 1.5 years). Mean age of the patients (65 / 67 years), mean target refraction (-1.8 diopters, D), and mean follow-up interval (2.9 / 3.4 years) were comparable in G1 / G2. Pre- and postoperatively refraction, keratometry, and best corrected visual acuity were recorded. Main outcome measures included the deviation of the spherical equivalent of the real refraction from the target refraction after cataract surgery. RESULTS: In G1 / G2 median visual acuity increased from preoperatively 0.2 / 0.15 to 0.6 / 0.5 after a follow-up period of 3 years on average. Mean deviation from target refraction was -0.3 ± 2.2 (-4.95 to + 3.15) D in G 1 and -0.4 ± 3.0 (-7.3 to + 7.25) D in G 2. After cataract surgery, the steepening of the cornea on average was significantly less in G 1 (0.5 ± 1.6 D) than it was in G 2 (3.3 ± 2.1 D; p = 0.003). CONCLUSIONS: Although the mean deviation from target refraction is minimal after cataract surgery following PKP, our results indicate a high level of variability. If corneal sutures have been completely removed before biometry, the accuracy of the IOL power calculation seems to be better.

Increased homocysteine levels in tear fluid of patients with primary open-angle glaucoma.

AIMS: We assessed homocysteine (Hcy) levels in tear fluid and plasma of patients with primary open-angle glaucoma (POAG). We determined the association between Hcy levels, dry eye syndrome and B vitamin status. METHODS: This prospective case-control study included 36 patients with POAG and 36 controls. Hcy concentrations were measured by high-performance liquid chromatography. RESULTS: Patients with POAG had significantly higher mean Hcy levels both in tear fluid (205 +/- 84 nmol/l; p < 0.001, t test) and in plasma (13.43 +/- 3.53 micromol/l; p = 0.001, t test) than control subjects (130 +/- 53 nmol/l and 10.50 +/- 3.33 micromol/l, respectively). Hcy in tear fluid was significantly correlated with plasma Hcy in POAG patients (r = 0.459; p = 0.005, Pearson's correlation), but not in controls (r = 0.068; p = 0.695). POAG patients with dry eye disease had significantly higher Hcy levels both in tear fluid and plasma than POAG patients without dry eye disease. There was no association between Hcy levels and B vitamin status in subjects with POAG. CONCLUSIONS: The study suggests increased Hcy levels in tear fluid and plasma of patients with POAG. Elevated Hcy levels might be a risk factor for POAG and dry eye syndrome in subjects with glaucoma.

[High-dose 106Ruthenium plaque brachytherapy for posterior uveal melanoma. A clinico-pathologic study]. / Hochdosisbrachytherapie des malignen Aderhaut- und Ziliarkörpermelanoms mit 106Ruthenium. Eine klinisch-pathologische Studie.

BACKGROUND: The purpose of this study was to report the multifactorial results of high-dose (106)Ruthenium plaque brachytherapy for (cilio-)choroidal melanoma and to confirm them by histological examinations. PATIENTS AND METHODS: 100 patients with choroidal or ciliochoroidal melanoma treated by high-dose 106Ruthenium plaque brachytherapy were followed-up for 5 years. 12 secondary enucleated eyes were compared to a non-irradiated matched group by light microscopy. RESULTS: The 5-year local tumour control rate was 93%, the 5-year survival rate 91%. Late radiogenic side effects occured as a retinopathy in 13%, as an optic neuropathy in 5% and as a secondary glaucoma in 3% of the patients. 14% had to be enucleated, 10% developed metastases. The histopathologic examination revealed significantly higher degrees of necrosis (p=0,041), balloon cell degeneration (p=0,025) and fibrosis (p<0,001) in the irradiated melanomas than in the control tumours. CONCLUSION: High-dose 106Ruthenium plaque brachytherapy turned out to be an effective treatment procedure for posterior uveal melanoma (not exceeding a prominence of 5,5 mm) with a high rate of local tumour control and a low rate of side effects.

[The penetrating keratoplasty. A 100-year success story]. / Die perforierende Keratoplastik. Eine 100-jährige Erfolgsgeschichte.

Ten precautions for prophylaxis of astigmatism in penetrating keratoplasty are recommended:1. The attempt should be made to determine donor topography for exclusion of previous refractive surgery, keratoconus/high astigmatism, and to allow for "harmonization" of donor and recipient topography.2. Donor and recipient trephination should be performed from the epithelial side with the same system, which is the prerequisite for congruent cut surfaces and angles in donor and recipient. For this purpose an artificial anterior chamber is used for donor trephination.3. Orientation structures in donor and host facilitate the correct placement of the first four or eight cardinal sutures to avoid horizontal torsion.4.A measurable improvement seems to be possible, using the Krumeich guided trephine system (GTS), the second generation Hanna trephine, and the Erlangen technique of nonmechanical trephination with the excimer laser.5. Horizontal positioning of the head and limbal plane are indispensable for state-of-the-art PKP surgery in order to avoid decentration, vertical tilt, and horizontal torsion.6. Graft size should be adjusted individually ("as large as possible, as small as necessary").7. Limbal centration should be preferred over pupil centration (especially in keratoconus).8. Excessive graft over- or undersize should be avoided to prevent stretching or compression of peripheral donor tissue.9. As long as Bowman's layer is intact a double running cross-stitch suture (according to Hoffmann) is preferred since it results in higher topographic regularity, earlier visual rehabilitation, and less suture loosening requiring only rarely suture replacement.10.Intraoperative keratoscopy should be applied after removal of lid specula and fixation sutures.

[Functional significance of adenosine receptors in the eye and their dysregulation in pseudoexfoliation syndrome]. / Funktionelle Bedeutung der Adenosinrezeptoren im Auge und ihre Dysregulation beim Pseudoexfoliationssyndrom.

BACKGROUND: Adenosine regulates many physiologic processes, such as aqueous humor secretion and intraocular pressure, via activation of its receptors. We investigated the expression of the receptor isoforms in eyes with PEX syndrome, which is associated with anterior chamber hypoxia and elevated intraocular pressure. MATERIALS AND METHODS: The mRNA and protein expression of the adenosine receptor subtypes in anterior segment tissues of patients with PEX syndrome, glaucomas, and normal control eyes were analyzed comparatively. RESULTS: Whereas the receptor subtypes A1, A2a, and A2b displayed no differential expression between PEX and control tissues, expression of the A3 adenosine receptor was consistently enhanced in the nonpigmented ciliary epithelium of all PEX eyes, independent of the presence of glaucoma, compared to normal and glaucomatous control eyes. CONCLUSION: Considering the known role of the A3 adenosine receptor in modulating aqueous humor secretion, its selective upregulation in the ciliary epithelium may confer cytoprotection and be accessible to therapeutic intervention in PEX patients.

Parapapillary retinal vessel diameter in normal and glaucoma eyes. II. Correlations.

The juxtapapillary diameters of the superior temporal and inferior temporal retinal artery and vein have been shown to be significantly smaller in glaucomatous eyes than in normal eyes. They had been measured in 473 eyes of 281 patients with chronic primary open-angle glaucoma and in 275 eyes of 173 normal subjects. In the current study the vessel diameters were correlated with intra- and parapapillary morphometric data and visual field indices. Only one eye per patient and subject was taken for statistical analysis. The retinal vessel calibers were significantly (P less than 0.001) correlated with: (1) the area of the neuroretinal rim as a whole and in four different optic disc sectors; (2) the rim width determined every 30 degrees; (3) the optic cup area and diameters; (4) the horizontal and vertical cup/disc ratios and (5) the quotient of them; (6) the retinal nerve fiber layer score; (7) the area of the parapapillary chorioretinal atrophy; and (8) the visual field indices. In the same eye the vessel caliber was smaller in that sector where the neuroretinal rim loss was highest and the retinal fiber layer score lowest. In intraindividual comparison the vessels were smaller in that eye with less neuroretinal rim tissue and lower nerve fiber layer score. No significant correlations were found with the form of the optic disc, the area of the peripapillary scleral ring, side, sex and refraction. The correlation coefficients were not significantly different when the control group was matched for age. The parapapillary retinal vessel diameter decreases with advancing glaucomatous optic nerve damage. It is correlated with morphometric intra- and parapapillary glaucomatous changes and perimetric defects.

Parapapillary chorioretinal atrophy in normal and glaucoma eyes. II. Correlations.

The parapapillary chorio-pigment-epithelio-retinal atrophy in glaucomatous eyes is significantly larger than in normal eyes. In a previous study its area and frequency have been measured in 582 eyes of 321 patients with chronic primary open-angle glaucoma and in 390 eyes of 231 normal subjects. In the current study the parapapillary changes were correlated with intrapapillary morphometric data and with perimetric indices. The parapapillary chorioretinal atrophy was significantly correlated with the neuroretinal rim area, the horizontal and vertical cup/disc ratios, the quotient of horizontal to vertical cup/disc ratio, the retinal nerve fiber layer score, and the mean visual field loss. It was larger in the same sector where the neuroretinal rim loss was more marked. The correlation coefficients were generally higher for zone "Beta," characterized by complete chorioretinal atrophy with visible large choroidal vessels and sclera, than for zone "Alpha," which showed irregular hypo- and hyperpigmentation. The parapapillary chorioretinal atrophy was correlated in location and time with the intrapapillary glaucomatous changes. It deserves attention in glaucoma diagnosis and follow-up. Its evaluation is especially valuable in eyes with small optic nerveheads (disc size less than 1.6 mm2) in which the intrapapillary glaucomatous changes occur later than the parapapillary ones.

Trabecular meshwork in pseudoexfoliation syndrome with and without open-angle glaucoma. A morphometric, ultrastructural study.

PURPOSE: To test the hypothesis that glaucoma in eyes with pseudoexfoliation (PEX) syndrome results from blockage of the outflow channels by PEX material, melanin granules from the iris pigment epithelium, or both, and to determine the origin of intratrabecular PEX material. METHODS: Trabecular meshwork tissue was obtained from five surgically enucleated eyes with PEX glaucoma, ten autopsy eyes with PEX syndrome without evidence of glaucoma, and six age-matched control eyes. Morphometric methods were used to measure the percentage area occupied by open spaces, cells, plaque material, PEX material, and melanin granules on electron micrograph montages of the entire filtration area and the juxtacanalicular tissue (JCT) area. RESULTS: Independent of the presence of glaucoma, most PEX deposits were located in the JCT adjacent to the inner and outer walls of Schlemm's canal, as well as in the uveal meshwork. Although ultrastructural evidence indicates the local production of PEX fibers in the JCT by endothelial and connective tissue cells, PEX material in the uveal meshwork is derived partly from the aqueous humor. A significant correlation could be established between the presence of glaucoma and the amount of PEX material in both the filtration area and the JCT, the average thickness of the JCT, and the mean cross-sectional area of Schlemm's canal. No significant correlation existed, however, between glaucoma status and the concentration of melanin granules or plaque material, and the cellularity. CONCLUSION: In addition to a mechanical obstruction by PEX material of exotrabecular origin, the apparent production of PEX material by trabecular cells may be principally responsible for glaucoma development. Accumulation of locally produced PEX material in the JCT, followed by dysfunction of endothelial cells and disorganization of JCT and Schlemm's canal, appear to be causative factors in the development of a special type of secondary open-angle glaucoma in PEX syndrome.

Parapapillary retinal vessel diameter in normal and glaucoma eyes. I. Morphometric data.

The retinal blood vessels serve for nutrition of the retinal ganglion cells and their axons. This study was undertaken to evaluate the vessel diameter in normal and glaucoma eyes. The calibers of the superior temporal and inferior temporal retinal artery and vein were measured at the optic disc border and at a distance of 2 mm from the optic disc center; 473 eyes of 281 patients suffering from chronic primary open-angle glaucoma and 275 eyes of 173 normal subjects were examined. Fifteen-degree, color stereo optic disc photographs were used. In the normal eyes the inferior temporal vessels were significantly larger than the superior temporal vessels. This corresponds with: (1) the configuration of the normal neuroretinal rim, which is significantly broader in the inferior disc region than in the superior disc area; (2) the visibility of the retinal nerve fibers, which are better detectable in the inferior temporal area than in the superior temporal one; and (3) the foveola location 0.53 +/- 0.34 mm inferior to the optic disc center. The retinal vessel diameter was independent of the patients' age and optic disc and parapapillary chorioretinal atrophy size. In the glaucoma group the vessel caliber was significantly smaller than in the normal eyes. The differences were more marked for the arteries and the inferior temporal vessels, respectively. The vessel diameters decreased significantly with increasing glaucoma stage independently of the patients' age. The parapapillary retinal vessel diameter may reflect the need of vascular supply in the corresponding superficial retinal area. It may be correlated with the local ganglion cell density and retinal nerve fiber layer thickness.

Optic disc, cup and neuroretinal rim size, configuration and correlations in normal eyes.

Four hundred and fifty-seven unselected normal human optic nerve heads of 319 subjects (163 men, 156 women, mean age 42.7 +/- 19.6 years) were evaluated by magnification-corrected morphometry of optic disc photographs. Mean optic disc surface measured 2.69 +/- 0.70 mm2 (0.80-5.54 mm2), mean diameter horizontally 1.76 +/- 0.31 mm (0.91-2.61 mm), and vertically 1.92 +/- 0.29 mm (0.96-2.91 mm). The form was slightly vertically oval. Optic cup area averaged 0.72 +/- 0.70 (0.00-3.41 mm2), mean horizontal cup diameter 0.83 +/- 0.58 mm (0.00-2.08 mm) and mean vertical diameter 0.77 +/- 0.55 mm (0.00-2.13 mm). The cup was significantly (P less than 0.0001) larger in discs with steep "punched-out" cups (1.37 +/- 0.62 mm2) compared to discs having cups with temporal flat slopes (0.59 +/- 0.39 mm2). Neuroretinal rim area ranged from 0.80 to 4.66 mm2 (mean 1.97 +/- 0.50 mm2), and was significantly correlated (P less than 0.00001) to the optic disc area. It was broadest in the inferior optic disc region (P less than 0.001), followed by the superior, nasal and temporal (P less than 0.001) regions. Horizontal cup/disc ratio (mean 0.39 +/- 0.28, minimum 0.00, maximum 0.87) was larger in 426 (93.2%) optic discs than the vertical one (mean 0.34 +/- 0.25, minimum 0.00, maximum 0.85). Concerning optic disc area, side differences of 0.10 mm2 or less were detected in 28%, of 0.2 mm2 or less in 46% and of 0.50 mm2 or less in 80% (cumulative frequencies). Concerning neuroretinal rim area, side differences of 0.10 mm2 or less were found in 31%, of 0.20 mm2 or less in 52% and of 0.50 mm2 or less in 84%.(ABSTRACT TRUNCATED AT 250 WORDS)

The HNK-1 epitope and the elastic fiber system of the human ciliary body. An immunoelectron microscopic study.

PURPOSE: To localize at the electron microscopic level the cell adhesion-related HNK-1 carbohydrate epitope in the inner connective tissue layer (ICTL) of the human ciliary body. METHODS: Seven specimens representing the pars plicata (age range, 12 to 86 years) and three specimens representing the pars plana (age range, 29 to 71 years) of the ciliary body were sampled at death from eight normal human eyes. Three additional specimens from the pars plicata were taken from three eyes with exfoliation syndrome (age range, 78 to 81 years). All specimens were embedded in LR white resin and studied by postembedding immunogold labeling using two monoclonal antibodies (mAbs) HNK-1 and NC-1 in detecting the HNK-1 epitope. RESULTS: In the ICTL of the pars plicata and the pars plana, mAbs HNK-1 and NC-1 constantly bound to the surface of fibroblast-like cells present in the subepithelial connective tissue matrix. The immunoreaction was localized along the cell membrane, both around the cell body and around its long, slender cytoplasmic processes. Long microfibrillar bundles, which consisted of approximately 10-nm thick microfibrils in close association with these subepithelial matrix cells and elastic fibers, were also labeled. The periphery of elastic fibers was likewise immunolabeled for the HNK-1 epitope. The reaction pattern was essentially the same, regardless of age and presence or absence of exfoliation syndrome. CONCLUSIONS: At the ultrastructural level, the HNK-1 epitope in the ICTL is a common denominator to the subepithelial matrix cells, microfibrillar bundles, and elastic fibers. This suggests that the subepithelial matrix cells secrete this epitope, and that molecules hearing it may be involved in joining these connective tissue elements that structurally stabilize the ciliary body.

Parapapillary atrophy and retinal vessel diameter in nonglaucomatous optic nerve damage.

Parapapillary chorioretinal atrophy and decreased retinal vessel diameter occur in glaucomatous eyes. To evaluate the frequency and degree of these signs in nonglaucomatous optic neuropathy, the authors evaluated morphometrically and compared 47 patients with nonglaucomatous optic nerve atrophy from extraocular causes with 292 patients with primary open-angle glaucoma and 179 normal subjects. Eyes with anterior ischemic optic neuropathy were excluded. The parapapillary atrophy was differentiated into a central zone (beta) with sclera and large choroidal vessels visible by ophthalmoscopy and a peripheral zone (alpha) with irregular pigmentation. Both zones did not differ significantly in the eyes with nonglaucomatous optic neuropathy and the normal eyes. In the glaucomatous eyes, they were significantly larger and occurred more frequently. The retinal vessel diameter was significantly smaller in both groups with optic nerve atrophy than in the normal group. It was concluded that decreased retinal vessel diameters unspecifically suggest optic nerve atrophy. Evaluation of parapapillary chorioretinal atrophy can be helpful in differentiating nonglaucomatous from glaucomatous optic neuropathy.

Zernike representation of corneal topography height data after nonmechanical penetrating keratoplasty.

PURPOSE: To demonstrate a mathematical method for decomposition of discrete corneal topography height data into a set of Zernike polynomials and to demonstrate the clinical applicability of these computations in the postkeratoplasty cornea. METHODS: Fifty consecutive patients with either Fuchs' dystrophy (n = 20) or keratoconus (n = 30) were seen at 3 months, 6 months, and 1 year (before suture removal) and again after suture removal following nonmechanical trephination with the excimer laser. Patients were assessed using regular keratometry, corneal topography (TMS-1, simulated keratometry [SimK]), subjective refraction, and best-corrected visual acuity (VA) at each interval. A set of Zernike coefficients with radial degree 8 was calculated to fit two model surfaces: a complete representation (TOTAL) and a representation with parabolic terms only to define an approximate spherocylindrical surface (PARABOLIC). The root mean square error (RMS) was calculated comparing the corneal raw height data with TOTAL (TOTALRMS) and PARABOLIC (PARABOLICRMS). The cylinder of subjective refraction was correlated with the keratometric readings, the SimK, and the respective Zernike parameter. Visual acuity was correlated with the tilt components of the Zernike expansion. RESULTS: The measured corneal surface could be approximated by the composed surface 1 with TOTALRMS < or = 1.93 microm and by surface 2 with PARABOLICRMS < or = 3.66 microm. Mean keratometric reading after suture removal was 2.8+/-0.6 D. At all follow-up examinations, the SimK yielded higher values, whereas the keratometric reading and the refractive cylinder yielded lower values than the respective Zernike parameter. The correlation of the Zernike representation and the refractive cylinder (P = 0.02 at 3 months, P = 0.05 at 6 months and at 1 year, and P = 0.01 after suture removal) was much better than the correlation of the SimK and refractive cylinder (P = 0.3 at 3 months, P = 0.4 at 6 months, P = 0.2 at 1 year, and P = 0.1 after suture removal). Visual acuity increased from 0.23+/-0.10 at the 3-month evaluation to 0.54+/-0.19 after suture removal. After suture removal, there was a statistically significant inverse correlation between VA and tilt (P = 0.02 in patients with keratoconus and P = 0.05 in those with Fuchs' dystrophy). CONCLUSIONS: Zernike representation of corneal topography height data renders a reconstruction of clinically relevant corneal topography parameters with a marked reduction of redundance and a small error. Correlation of amount/axis of refractive cylinder with respective Zernike parameters is more accurate than with keratometry or respective SimK values of corneal topography analysis.

Cell density of human lens epithelium in women higher than in men.

Flat preparations of the central lens epithelium in 181 human donor eyes, 120 male, 61 female, were used to determine epithelial cell density. Donor age ranged from 13 to 91 years. A similar linear age-dependent decrease of cell density was found in both sexes. In addition, the epithelial cell density was significantly higher in females. The age-adjusted mean cell density in males was 5008.6 cells/mm2, in females 5780.6 cells/mm2. A similar sex difference had been found before in lens epithelium of human cataracts. The cause and significance of this observation are unknown.

Increased extracellular deposition of fibrillin-containing fibrils in pseudoexfoliation syndrome.

PURPOSE: To localize the distribution of fibrillin-containing microfibrils in normal human anterior segment tissues and to characterize the role of fibrillin in the pathogenesis of pseudoexfoliation syndrome. METHODS: Anterior segment tissues were obtained from 10 eyes with pseudoexfoliation syndrome and 10 normal eyes and investigated by indirect immunofluorescence and electron microscopic immunogold labeling using a monoclonal antibody to fibrillin-1. RESULTS: In addition to labeling of zonular fibers, fibrillin-immunoreactive microfibrillar bundles generally were found in the corneal stroma; the stromal connective tissues of conjunctiva, ciliary body, and iris, especially in the iris root area; the periphery of Schlemm's canal, the scleral spur, and the most anterior portion of the trabecular meshwork; the ciliary muscle, and the dilator and sphincter muscles of the iris; the basement membranes of peripheral corneal epithelium, conjunctival epithelium, ciliary pigmented epithelium, and the lens capsule. The microfibrillar bundles were found to be isolated or in association with elastic fibers and cellular basement membranes. In pseudoexfoliation eyes, an additional strong immunoreaction was localized to pseudoexfoliation fibers and their microfibrillar subunits in close proximity to surfaces of cells involved in pseudoexfoliation fiber production. CONCLUSIONS: The fibrillin-containing microfibrillar system in normal ocular tissues is suggested to have a substantial role in the maintenance of tissue integrity by providing tensile strength and flexibility to mechanically strained tissues. The findings further provide evidence for fibrillin as an intrinsic component of pseudoexfoliation fibers, suggesting the possibility that enhanced expression of fibrillin or abnormal aggregation of fibrillin-containing microfibrils may be involved in the pathogenesis of pseudoexfoliation syndrome.

Desmosomal-mitochondrial complexes in human nonpigmented ciliary and retinal pigment epithelia.

In the normal human nonpigmented ciliary epithelium structural associations between mitochondria and desmosomes are described electron-microscopically: either a single desmosome or a linear array of several desmosomes joined by filamentous bundles is associated with one or two mitochondria (19.6 +/- 5.4%; n = 29). The frequency of occurrence of these complexes was studied in five different regions of the ciliary body; analysis of covariance revealed a significantly increased number of associations in the ciliary processes. Further, the age dependence of their occurrence was examined in 29 different age classes (15 to 86 years); correlation analysis revealed no correlation between age and number of associations. Similar complexes occur, in addition, in the retinal pigment epithelium, but have not been observed in ciliary pigmented, lens, iris and corneal epithelia. Desmosomal-mitochondrial complexes are considered to be a characteristic feature of basic physiological significance of certain epithelia only. The cytochemical demonstration of calcium in the associated mitochondria provides support for the hypothesis that the mitochondria may serve as buffers for intracellular calcium by controlling the local calcium concentration, thus increasing the stability and functional integrity of desmosomal junctions in secretory or actively transporting epithelia with high endogenous calcium levels.

Histomorphometry of the human optic nerve.

This study was undertaken to measure number, diameter and distribution of nerve fibers in normal human optic nerves. Twenty-two optic nerves of 19 subjects aged between 20 and 75 years were histomorphometrically examined using semithin sections obtained in a distance of 2 to 5 mm behind the globe. The mean nerve fiber count was 1,159,000 +/- 196,000 with a minimum of 816,000 and a maximum of 1,502,000. The significant (P = 0.025) loss per year of age was approximately 5426 nerve fibers. For eight subjects the nerve fiber count was independent of the size and form of the optic disc. The mean minimal nerve fiber diameter averaged 1.00 +/- 0.06 micron (range: 0.1-8.3 microns). It was significantly smaller in the temporal and inner region of the optic nerve than in the nasal and outer area, respectively. Correspondingly, nerve fiber count per area was significantly higher in the temporal and inner parts of the optic nerve than in the nasal and outer parts, respectively. Statistically different size classes could not be detected. The optic nerve cross-section area excluding the leptomeninges (mean 8.09 +/- 1.38 mm2) increased significantly with the nerve fiber count. The marked interindividual variability of the nerve fiber count may influence interindividual comparisons of psychophysical examinations. It can indicate an interindividually different anatomic "reserve capacity" in the course of optic nerve diseases. The age-dependent nerve fiber loss, among other factors, may partially explain the decreased visual performance of older subjects. It should be considered in progression and "pseudoprogression" of optic nerve diseases like glaucoma. The intraindividually high variability of the nerve fiber size may correspond to different retinal ganglion cell populations.

Morphometry of the human lamina cribrosa surface.

The lamina cribrosa is a sieve-like perforation in the posterior part of the sclera, that allows passage of the retinal ganglion cell axons and central retinal vessels and preserves a pressure gradient between the intraocular and extraocular space. It has been termed the primary site of glaucomatous damage to the optic nerve. Using electron microscopy, the authors morphometrically evaluated the inner surface of the lamina cribosa in 40 normal human donor eyes. There were 14 men and 21 women with a mean age of 52 +/- 22 yr (10-82 yr). Mean single pore area (0.004 +/- 0.001 mm2) and summed pore area were significantly (P less than 0.05) larger and the ratio of summed pore area to lamina area was higher in the inferior and superior regions than in the temporal and nasal regions. The ratio decreased with increasing lamina cribrosa size. Count, size, form, and density of the pores were statistically independent of age, sex, side, and lamina cribrosa form. Pore count and summed pore area (mean: 0.92 +/- 0.22 mm2) increased significantly with enlarging lamina cribrosa size. The area of the lamina cribrosa openings for passage of the central retinal vessels was independent of the lamina cribrosa size. The high ratio of summed pore area to lamina area and the large single pore area may be pathogenetically important for the increased glaucoma susceptibility in the inferior and superior disc regions. The lack of a correlation between lamina cribrosa size and the area of the lamina cribrosa openings for the retinal vessels may explain why central retinal vessel occlusions occur independently of optic disc size.

Parapapillary chorioretinal atrophy in normal and glaucoma eyes. I. Morphometric data.

Glaucomatous optic nerve damage is associated with alterations of the intra- and parapapillary optic disc area. We measured and compared the parapapillary region in 582 eyes of 321 patients suffering from chronic primary open-angle glaucoma and in 390 eyes of 231 normal subjects. Only one randomly assessed eye per patient and subject was taken for statistical analysis. Highly mopic eyes with a myopic refractive error of more than -8.00 diopters had been excluded. The parapapillary chorioretinal atrophy was divided into a peripheral zone "Alpha" with irregular hyper- and hypopigmentation, and a more central zone "Beta" characterized by whitish colour, visible large choroidal vessels and visible sclera. In the normal eyes both zones were significantly (P less than 0.001) largest and most common in the temporal horizontal sector, followed by the inferior temporal sector, the superior temporal sector and finally the nasal sector. In the glaucoma group both zones were significantly larger (P less than 0.0001; Mann-Whitney test) and more frequent than in the normal eyes (0.40 +/- 0.32 mm2 versus 0.65 +/- 0.49 mm2 for zone Alpha, 0.13 +/- 0.42 mm2 versus 0.79 +/- 1.17 mm2 for zone Beta). The differences were significant also for the earliest glaucoma stage of this study. They were most marked for the nasal parapapillary sector. Significant differences (P less than 0.001) between the normal group and the earliest glaucoma stage were: zone Alpha larger than 0.20 mm2 or broader than 0.20 mm in the temporal horizontal sector, total area of zone Alpha larger than 0.30 mm2, occurrence of zone Alpha in the nasal sector, and occurrence of zone Beta anywhere.

Protein quantification and electrophoresis in aqueous humor of pseudoexfoliation eyes.

PURPOSE: Pseudoexfoliation (PSX) eyes frequently show clinical signs of blood-aqueous barrier impairment. To analyze these alterations, the authors examined aqueous humor of human eyes with and without PSX. METHODS: After aqueous humor samples had been obtained during cataract or filtering glaucoma surgery, a modified Pierce-bicin choninic acid assay was used to quantify total aqueous protein concentration in 27 PSX eyes and 37 eyes without clinical signs of PSX (12 cataract eyes and 25 eyes with primary open-angle glaucoma). In addition, aqueous protein composition was analyzed by sodium dodecylsulfate polyacrylamide gel electrophoresis, silver staining, and laser densitometry in 27 PSX eyes and 59 eyes without PSX. RESULTS: Aqueous protein concentration was significantly higher in PSX (mean 0.42 +/- 0.16 mg/ml) than in normal cataract eyes (0.22 +/- 0.08 mg/ml, P < 0.0001) and in eyes with open-angle glaucoma (0.26 +/- 0.09 mg/ml, P < 0.0001, Wilcoxon-Mann-Whitney test). Electrophoresis revealed a characteristic increase of a 12.5-kDa band in 15 of 27 PSX eyes but in only 1 of 59 eyes without PSX (P < 0.00001, chi-square test). CONCLUSIONS: These results substantiate increased aqueous protein concentration and aqueous barrier impairment in PSX. The additional finding of an increased 12.5-kDa band in 56% of PSX eyes may be related to the pathogenesis of PSX in the anterior ocular segment.