Ciliary body toxicity of cyclosporin A and octreotide acetate in rabbit eyes: a comparison with mitomycin C and 5-fluorouracil

Purpose To compare the toxicities of cyclosporin A, octreotide acetate, mitomycin C and 5-fluorouracil to the ciliary body.Method We applied sponges soaked in these compounds to the open scleras of rabbit eyes. Histopathological specimens were obtained from the operation site and at 180° from it on the 14th day after surgery.Results Mean ciliary epithelial thickness in the study groups was as follows: 12.29±2.69 m in group 1 (mitomycin C), 13.85±4.56 m in group 2 (5-fluorouracil), 17.71±3.09 m in group 3 (cyclosporin A), 11.64±2.92 m in group 4 (octreotide acetate), 11.92±2.89 m in group 5 (topically applied octreotide acetate) and 21.85±4.29 m in group 6 (control). The ciliary epithelial thickness in groups 1, 2, 4 and 5 was statistically different from that in the control group. Intracellular vacuolisation and degenerative changes of the non-pigmented epithelium, and pigment loss of the pigmented epithelium, were found mostly in group 1 and moderately in group 2 and 3.Conclusion Octreotide acetate and cyclosporin A are less toxic alternatives to mitomycin C and 5-fluorouracil in glaucoma filtration surgery.     

Selective reduction of oscillatory potentials and pattern electroretinograms after retinal ganglion cell damage by disease in humans or by kainic acid toxicity in cats

We recorded pattern electroretinograms, scotopic threshold responses, oscillatory potentials and ganzfeld flash electroretinograms in patients with glaucoma or other optic nerve diseases and in cats with inner retinal damage caused by intravitreal injections of kainic acid. In both studies, the scotopic b-wave and the scotopic threshold responses were normal but the oscillatory potentials and pattern electroretinograms were not. The photopic b-wave was also often reduced in patients with scotopic oscillatory potential reduction, and the reduction was proportionate to the oscillatory potential change. Oscillatory potentials were as frequently reduced as pattern electroretinograms in both patient groups, and in the few cases where only one response was reduced, there was no bias toward either measure. In cats, the effects of intravitreal injection of various doses of kainic acid on the retina were evaluated electrophysiologically, and structural damage was assessed histologically. After 25 nmol of kainic acid, the pattern electroretinograms and oscillatory potentials were reduced but neither the b-waves nor the scotopic threshold responses, were affected. Histologic studies of retinas after this dose showed swollen dendrites that were restricted to the outer part (off-sublamina) of the inner plexiform layer. Serial semithin sections indicated that most, if not all, of the swelling was confined to dendrites of large ganglion cells. Our results indicate that the size and sensitivity of the oscillatory potential response may have a role in the diagnosis and management of early glaucoma and optic nerve disease, and that the photopic electroretinogram may give similar information.     

Die Stereo-Ultrastruktur der Cornealoberfläche bei der Ratte

Zusammenfassung Die dreidimensionale Beschaffenheit der Cornealoberfläche der Ratte wurde mittels des Scanning Electron Microscope und anhand konventioneller elektronenmikroskopischer Schnittpräparate untersucht. Dabei konnte das Vorhandensein von Mikrovilli (0,15 breit, bis 1,0 hoch) und von Mikroplicae (0,1–0,2 breit, 0,3–0,4 hoch, 1–3 lang) nachgewiesen werden. Bei diesen Strukturen dürfte es sich um während der Desquamation entstandene Ausstülpungen der Epithelzellmembran im Bereiche der Desmosomen handeln.

---

The stereo ultrastructure of the corneal surface in rat

Summary Combined morphological examination of the corneal surface of rat both with the scanning and the transmission electron microscope reveals two kinds of protrusions covering the polygonal, regularly arranged epithelial cells: Mikrovilli and Mikroplicae; the former being approximatively 0.15 large and up to 1.0 high, the latter being 0.1–0.2 large, 0.3–0.4 high and 1–3 long. These formations are with high probability the remnants of desmosomes having been formed during desquamation.

---

---

Diese Untersuchungen wurden mit Unterstützung des Fonds National suisse de la recherche scientifique (Nr. 5322.3) durchgeführt.     

Ultrasound biomicroscopic analysis of the effect of pilocarpine on the anterior chamber angle

Background: This study was carried out to determine the effects of pilocarpine on the anterior chamber angle in healthy volunteers. Methods: We measured changes in anterior chamber depth (ACD), trabecular-iris angle (TIA), angle opening distance at 250 and 500 m from the scleral spur (AOD250 and AOD500), and iris thickness using ultrasound biomicroscopy in 48 eyes of 48 normal volunteers (ages 18–57 years, mean 34.8 years) before and 1 h after instillation of 2% pilocarpine. Results: Pilocarpine altered the TIA by –18.6° to + 10.5° (mean –4.16°), and change in the TIA increased significantly and linearly in relation with decrease in the pretreatment TIA (r = 0.929). Pilocarpine altered AOD250 change by –136 to +94 m (mean –38 m) and AOD500 by –151 to +157 m (mean –42 m); changes in the AOD250 and AOD500 were significantly correlated to the pretreatment AOD250 and AOD500 values, respectively (r = 0.923 andr = 0.896, respectively). The pilocarpine-induced change in the ACD showed a linear relationship to the pretreatment ACD (r = 0.887). The changes in the TIA, AOD250 and AOD500 showed greater increases in association with lower pretreatment ACD (r = 0.848,r = 0.891,r = 0.842) and smaller change in the ACD (r = 0.834,r = 0.839,r = 0.812). Conclusions: The response of the anterior chamber angle to pilocarpine, narrowing or widening, depended on its pretreatment state. The ability to predict the pilocarpine-induced change in the angle before the instillation of pilocarpine would be helpful in treating patients with glaucoma.     

Determination of the pseudofacility by fluorophotometry in the human eye

Purpose: Pseudofacility (decrease in aqueous humor flow in response to increase in the intraocular pressure (IOP)) has been evaluated in animals and in humans by a combination of different techniques that seriously alter the ocular physiology, such as the cannulation of the eyeballs, use of radioactive isotopes, perilimbic suction cups or tonography. Very different results have been obtained. Our objective is to relate the value of the aqueous humor flow in humans (as measured by fluorometry) with IOP. In order to obtain the widest range of IOP possible, we have performed this study in both normal as well as glaucoma patients. Methods: 48 eyes were studied, corresponding to 31 subjects (mean age 58 ± 14 years). Of these, 21 corresponded to normal subjects and 27 to glaucoma patients. The aqueous humor flow (F) was determined by fluorophotometry (Protocol of Yablonsky) and the IOP was measured thereafter. Results: The mean value of F was 2.1 ± 0.5 l/min for healthy eyes and 2.2 ± 0.7 l/min for glaucoma-affected eyes. The values were not different (p > 0.1). The mean value of the IOP was 15.3 ±3.1 mmHg in the normal population and 22.1 ± 4.3 mmHg in the glaucoma patients. A linear relationship between F and IOP was found (r = – 0.41, p < 0.05, decrease in F = 0.081 l min^–1 mmHg^–1). Conclusions: The value of the pseudofacility in the humans can be estimated at 0.081 l min^–1 mmHg^–1, which constitutes 27% of the total outflow facility. This figure also makes it possible to estimate the role of the ultrafiltration in blood in the production of the aqueous humor since it is assumed that active secretion is pressure-independent. The results obtained are concordant with a secondary but no unimportant role of the plasmatic ultrafiltration with respect to the active secretion.     

Toxicity and efficacy of intravitreal injection of spartanamicin B* in the treatment of Candida endophthalmitis **

Aims/Background: We evaluated the retinal toxicity of spartanamicin B and its efficacy in a rabbit model of Candidal endophthalmitis. Methods: Toxicity. Fourteen albino rabbit eyes were injected intravitreally with spartanamicin B (1, 2, 5, 10, 25, 50, and 100 g) ; 2 eyes received the vehicle alone. Efficacy. Ten rabbit eyes were inoculated with 3000 Candida organisms which caused endophthalmitis in 24 hours. Eight eyes were treated with intravitreal spartanamicin B in doses of 1, 2, 5, or 10 g/0.1 ml; 2 untreated eyes served as controls. Results: Toxicity. The eyes injected with 10 g and the control group eyes exhibited no clinical, histological, or electroretinographic evidence of retinal toxicity. Doses > 10 g caused vitritis. Efficacy. Clinical examination of the treated eyes showed a gradual improvement over 3–6 days; mild opacities remained until day 14. Results of cultures performed 15 days after infection were negative in all treated eyes. Conclusions: Intravitreally injected spartanamicin B (10 g) is nontoxic to the retina, effective against C. albicans in the endophthalmitis model in the rabbit eye and caused no discernible histological changes in the retina.     

Human conjunctival surface mucins: A quantitative study of normal and diseased (KCS) tissue

The architecture and distribution of surface mucins were studied qualitatively and quantitatively by transmission electron microscopy in ruthenium red stained biopsies of the human conjunctiva. Six control specimens were compared with three from early keratoconjunctivitis sicca (KCS) and with three specimens from severe KCS cases. The area of the ruthenium red/Os04/mucin reaction product on the conjunctival epithelial surface was measured by image analysis and the values were expressed in m² per m length of epithelium. The total area of surface mucins was differentiated from the narrow zone of mucins in close contact with the microplicae. The value for total mucins in two cases of early KCS was higher (0.4 m²/m) than the control range (0.1–0.3 m²/m) due to the presence of large clumps of mucins on the surface. The values for microplical mucins in early and severe KCS were within the control range, but were an overestimate owing to the presence of abnormal structures, e.g. vesicles, and abnormal clumps on the surface. This morphometric technique has limitations, but with appropriate material it might be a useful tool for the identification of conjunctival surface mucins.This paper was presented in part at the Eighth Annual Meeting of the European Club for Ophthalmic Fine Structure in West Berlin on 28th, 29th March, 1980     

Increased release of tenascin in tear fluid after photorefractive keratectomy

Background: Extracellular matrix protein tenascin (TN) is expressed in the anterior stroma during corneal wound healing. In this study we analysed TN release in tear fluid after photorefractive keratectomy (PRK). Methods: Tear fluid TN concentrations of ten PRK patients were measured with an immunoassay. Tear fluids were collected preoperatively and 1, 2 and 7 days after PRK. The tear fluid collection time and the volume of tears collected were registered. Because tear fluid flow was greatly increased postoperatively, tear fluid flow-corrected release (TN flux) was calculated. Results: The tear fluid flow was 4.50±0.94 l/min (mean±SEM) preoperatively, 55.48±16.70 l/min (P<0.01) on the 1st, 33.91±7.91 l/min (P<0.01) on the 2nd, and 13.79±5.49 l/min (P>0.05) on the 7th postoperative day. The preoperative TN concentration was 0.85±0.20 g/ml. On the 1st postoperative day it decreased to 0.37±0.17 g/ml (P>0.05), most likely due to the dilution effect caused by hypersecretion after PRK. The TN concentration was 0.67±0.12 g/ml (P>0.05) on the 2nd and 0.78±0.15 g/ml (P>0.05) on the 7th postoperative day. The preoperative TN flux was 5.23±1.88 ng/min. On the 1st and 2nd postoperative days the TN flux was 14.40±4.99 ng/min (P<0.05) and 22.66±6.I2 ng/min (P<0.05), respectively. On the 7th postoperative day a tendency towards decreased flux (14.00±6.02 ng/min, P>0.05) was observed. Conclusion: Although there is a minor decrease in TN concentration after PRK due to increased tear fluid flow, a significant increase in TN flux was observed. Complete reepithelialization of the ablated area was observed in all eyes at the follow-up visit on postoperative day 7.     

Large rod-like photopic signals in a possible new form of congenital night blindness

A 10-year-old Persian girl has symptoms of congenital stationary night blindness and some drusen-like lesions in the region of the vascular arcades. Her electroretinogram shows no rod response to a weak stimulus, but a large (475 V) slow scotopic response to a strong stimulus that is unchanged by photopic conditions (15 F1 background illumination). However, the response to flicker had the typical (smaller) amplitude of a cone signal. This may represent a new form of night blindness in which rod sensitivity is reduced so that there is no vision under dim conditions but rod function still persists under photopic conditions.     

The effect of the water-drinking test on aqueous humor dynamics in healthy volunteers

In 19 healthy volunteers (9 men, 10 women) we studied the effect of drinking 1000 ml of water within 10 min on aqueous humor dynamics. Fluorescein was applied topically five times, 6 h before measurements. All readings were taken during the afternoon. The Wilcoxon signed-rank test was used to evaluate the statistical relevance of the data. Aqueous humor flow was measured 60 min before (F1) and 10 min (F2), 30 min (F3), 60 min (F4) and 90 min (F5) after drinking 11 of water. Flow (mean ± SD) changed as follows: F1, 2.25 ± 1.2 ll/min ; F2, –3.29 ± 3.4 /min (P < 0.0000); F3, 1.69 ± 1.0 gml/min (P=0.007); F4, 2.39±0.9 l/min (P=0.25); F5, 2.64±0.9 l/min (P=0.02). Three to four days later the identical procedure was performed in each individual: F1, 2.06 ± 1.0 l/min F2, –3.12 ± 2.4 l/min (P < 0.0000); F3, 1.09 ± 0.6 l/min (P < 0.0001); F4, 1.76 ± 0.6 l/min (P=0.15); F5, 2.54±0.8 l/min (P=0.01). The correlation coefficient for the left and night eyes (F1–F5, both days) was r=0.85. The mean flow in the 19 healthy volunteers during the afternoon hours was 2.25 ± 1.0 l/min. Water load consistently led to a reflux of unbound fluorescein into the eye about 10 min later. This is documented as a negative flow. Ninety minutes after drinking 1000 ml of water there is a significant increase in flow, which is in contrast to the normal diurnal curve of aqueous humor dynamics. Water load causes hydremia and an increase in episcleral venous pressure. Fluorophotometry together with water load may be useful to study the aqueous humor dynamics in healthy and glaucomatous eyes and eyes with ocular hypertension.     

Topical and intravenous gentamicin in traumatically lacerated eyes

Intravenous or topical gentamicin may be the initial mode of treatment for lacerated or ruptured eyes by emergency room physicians while awaiting ophthalmic consultation and surgical repair. The purpose of this study was to determine the possibility of having retinotoxic intravitreal gentamicin concentrations in experimentally lacerated rabbit eyes treated with either intravenous or topical gentamicin separately or in combination with each other. Nontoxic concentrations of gentamicin were found in the vitreous bodies by all routes of drug administration. After 3 h intravitreal concentrations of gentamicin were: 0.20–0.30 g/ml when treated intravenously, 0–2.9 g/ml when treated topically, and 0.20–0.51 g/ml when treated both intravenously and topically. While the upper range of topically applied gentamicin concentrations (2.9 g/ml) is therapeutic for some pathogens, the wide range of intravitreal concentrations (0–2.9 g/ml) achieved does not indicate that topically applied gentamicin with or without intravenously administered gentamicin can reliably achieve therapeutic concentrations. Offprint requests to: M.O. Yoshizumi

---

     

The routes for bulk drainage of aqueous humour in rabbits with and without cyclodialysis

Summary The bulk drainage of aqueous humour into the general circulation and into the orbital tissues was studied with ¹³¹I-labelled albumin and red dextran (molecular weight 40,000) in rabbits with and without cyclodilaysis.In animals at a normal intraocular pressure of about 20 mm Hg and without an artificial cleft between the anterior chamber and the suprachoroid the rate of aqueous bulk flow into the general circulation was 3.99 ± 0.55 l/min. There seemed to be some outflow also through other routes ending up in the episcleral tissues in the limbus region but less than 0.11 ± 0.02 l/min was drained in that way.Even in dead eyes maintained at an intraocular pressure of 14 mm Hg only negligible quantities of labelled anterior chamber fluid passed into the tissues with bulk flow.In acute experiments in living animals, after a cleft had been opened between the anterior chamber and the suprachoroid without damaging the sclera, the rate of aqueous production was 5.64 ± 0.65 l/min. On an average 54% of the aqueous humour was drained into the suprachoroid from where great amounts penetrated the sclera in part by way of perivascular spaces in part directly through the scleral substance. Before the cleft was produced the facility of outflow was 0.237 ± 0.038 l/min per mm Hg, afterwards it was on an average 0.505 ± 0.092 l/min per mm Hg higher.

---

Zusammenfassung Der bulk Abfluß von Kammerwasser in den Blutstrom und in die Gewebe der Orbita wurde in normalen und cyclodialysierten Kaninchen mit ¹³¹I-Albumin and rotem Dextran (Molekulargewicht 40,000) studiert. In Tieren mit normalem intraocularen Druck (20 mm Hg) war der Abfluß ins Blut 3.99 ± 0.55 l/Min. Es gab wahrscheinlich auch einen Abfluß in die Gewebe, aber dieser Abfluß war geringer als 0.11 ± 0.02 l/Min. Auch in toten, perfundierten, Augen gab es bei einem intraocularen Druck von 14 mm Hg nur einen sehr geringen Abfluß in die Gewebe.Nachdem in akuten Experimenten ein Spalt zwischen der Vorderkammer und dem Suprachoroidalraum geöffnet war, war die Kammerwasserproduktion 5.64 ± 0.65 l/Min. Durchschnittlich 54% davon wurden zum Suprachoroidalraum drainiert, von wo große Mengen die Sklera zum Teil durch perivaskulare Spatien, zum Teil direkt durch die Skleralsubstanz durchsetzten. Bevor der Spalt geöffnet wurde, war die Abflußfazilität 0.237 ± 0.038 l/Min per mm Hg, nachher war sie um 0.505 ± 0.092 l/Min per mm Hg gesteigert.

---

Résumé Le bulk drainage d'humeur aqueuse dans la circulation générale et dans les tissues orbitaux était étudié avec d'albumine marquée par ¹³¹I et de dextrane rouge (poids moléculaire 40,000) chez des lapins avec et sans cyclodialyse. Chez des animaux avec une pression intraoculaire normale d'environ 20 mm Hg et sans une communication artificielle entre la chambre antérieure et la suprachoroïde la vitesse du bulk flux aqueux dans la circulation générale était 3.99 ± 0.55 l/min. Il semblait avoir quelque flux aussi par d'autres voies directement dans le tissue épiscléral dans la région limbale; mais moins que 0.11 ± 0.02 l/min. était drainé ainsi.Même dans des yeux morts maintenus sous une pression intraoculaire de 14 mm Hg seulement des quantités insignifiantes d'humeur aqueuse marquée filtraient de la chambre antérieure dans le tissu épiscléral comme bulk flux. Dans des expériences aiguëes avec des animaux vivants, après avoir fait une ouverture entre la chambre antérieure et la suprachoroïde sans blesser la sclérotique, le débit de l'humeur aqueuse était 5.64 ± 0.65 l/min. En moyenne 54% de l'humeur aqueuse étaient drainés dans la suprachoroïde, et de là partiellement par des espaces périvasculaires partiellement par la substance sclérotique. Avant que l'ouverture était créée la facilité du flux était 0.237 ± 0.038 l/min per mm Hg, après elle était en moyenne 0.505 ± 0.092 l/min per mm Hg plus haut.

---

---

Department of Pharmacology, University of Uppsala.     

Über das Vorkommen lichtempfindlicher,fluorescierender Substanzen in verschiedenen Geweben von Rinderaugen

Zusammenfassung und Ergebnisse Papierchromatographisch wurde aus Hornhäuten, Linsen und Netzhäuten von Rindern eine nach denR _f -Werten und UV-Spektren gleiche Substanz isoliert. Sie fluorescierte im alkalischem Medium leuchtend grün, im sauren leuchtend blau. Die Absorptionsmaxima lagen in n/10 Natronlauge bei 258–260 m und bei 400 m und in n/10 Salzsäure bei 258–260 m und bei 360 m. Auffallend war die starke Lichtempfindlichkeit dieser Verbindung. Eine Identifizierung der fluorescierenden Substanz gelang nicht. Auf Grund der gefundenen UV-Spektren und derR _f -Werte in Pteridinlaufmitteln kann vermutet werden, daß es sich um ein Pteridin handeln könnte.Mit 5 Textabbildungen     

Gene transfer in the RPE65 null mutation dog: relationship between construct volume,visual behavior and electroretinographic (ERG) results

In vivo gene transfer in a large group of RPE65 null mutation dogs have been recently performed. The present study was aimed at determining, through visual behavioral and electroretinographic (ERG) testing, if there is a volume effect of the gene construct administered. Eleven Beagle-Briard dogs homozygous for the RPE65 null mutation and two unaffected control dogs were included. Affected animals were unilaterally treated with either a high (70–100 l; N = 6) or a low volume (30–60 l; N = 5) of subretinally injected rAAV.RPE65 construct, at the age of 4 months to 2.5 years. Fellow eyes were treated with a subretinal injection of rAAV.GFP or sham operated and used as internal controls. Retinal function was measured pre- and 10–12 weeks post-surgically, using simultaneous bilateral full-field flash ERGs. A significant improvement in all ERG responses studied was identified for the high volume treated group compared to pre-surgical parameters. A significant improvement for the high intensity scotopic a-wave response for the low volume rAAV.RPE65 treated group was also found. Objective and subjective dim and day light visual maze testing, in eight of the affected treated animals, and the two control dogs, revealed better vision in daylight than in dim light for all animals. Vision in dogs treated with the high volume of gene construct was significantly better in day light than in dim light. No significant difference was noted between day and dim light testing for the control group or those animals treated with a low volume of the gene construct. Significantly better vision was noted in the control group when compared with the low volume group under dim light conditions, and the high volume group under day light conditions. No significant difference in functional vision could be identified between the high volume treated animals and control animals in day light conditions. These findings support the hypothesis that functional vision is improved by subretinal rAAV.RPE65 injection in a volume-dependent manner.     

Macular pigment density in age-related maculopathy

Purpose Macular pigment (MP) is believed to have a protective role in the development and progression of age-related maculopathy (ARM). We present results of measurements of macular pigment density (MPD) in patients with ARM at different stages with a modified confocal scanning laser ophthalmoscope (HRA, Heidelberg Engineering, Heidelberg, Germany).Method ARM patients were categorized into four groups. Staging depended upon the size of drusen, geographic atrophy, and loss of visual acuity due to ARMD in the fellow eye; 1: drusen size <125 m, 2: drusen size >125 m, 3: drusen size <125 m+ARMD in fellow eye, and 4: drusen size >125 m+ARMD in fellow eye. We took autofluorescence images at 488 nm and 514 nm with a modified HRA. MP density was evaluated within 2° around the center of the fovea. In this study, we included 146 patients with ARM: 26 in group 1, 19 in group 2, 80 in group 3, and 21 in group 4.Results The mean MPD of the different stages of ARM was: in group 1, 0.233±0.091 DU; group 2, 0.218±0.102 density units (DU); group 3, 0.252±0.085 DU; and group 4, 0.208±0.100 DU. Statistical analysis (Kruskal–Wallis test) showed no differences between groups.Conclusions Recent studies in ARM did not result in significant differences of MPD between the various stages of ARM. Further longitudinal studies are requested to compare the incidence of ARMD in eyes with high and low MPD in order to provide definite evidence of the influence of MPD on the progression of ARMD.Presented in part at the annual meeting of the Deutsche Ophthalmologische Gesellschaft (DOG), Berlin, 2003.     

Intraoperative retinal light damage reflected in electrophysiologic data

In a series of 30 unilaterally pseudophakic patients, electroretinograms and electrooculograms were recorded 6 months postoperatively. The unoperated on fellow eyes served as controls High intraoperative retinal light exposure (3.4–7.3 mW/cm², Zeiss OPMI 6 operating microscope) caused a substantial reduction of electrophysiologic potentials. Light protection prevented deterioration of electroretinogram and electro-oculogram potentials; reducing the bulb voltage, tilting the axis of illumination, filtering short wavelengths and the use of light shields resulted in 4-log-unit lower intensities (0.8–3.7 W/cm²).Abbreviations ACL anterior chamber lens - ECCE extracapsular cataract extraction - ICCE intracapsular cataract extraction - PCL posterior chamber lens     

Scotopic versus photopic pattern onset-offset electroretinograms

We investigated the contribution of rods and cones to the human pattern electroretinogram to onset and offset checkerboards of different spatial frequency and wavelength in a 39° × 39° field. Under strictly scotopic conditions, there was a negative potential at onset and a positive potential at offset, whereas under photopic conditions, there was a positive potential at onset and a negative/positive potential at offset. Thus, the waveform to pattern onset (offset) was that of the luminance electroretinogram to decreasing (increasing) luminances. For pattern onset, the sensitivity difference 486–601 nm under scotopic and photopic conditions closely followed the luminosity function of rods and cones. The amplitude of the scotopic onset response increased with check size up to 3°30 and that of the photopic onset response, up to 30. With larger checks, the scotopic and photopic onset response markedly decreased. This indicates antagonistic center-surround organization of the receptive fields under both scotopic and photopic conditions. By contrast, the offset response monotonically increased with check size under scotopic and photopic conditions, which suggests a luminance component in the pattern electroretinogram. Consequently, the pattern electroretinogram to reversing checker-boards has to be regarded as a mixture of both pattern- (contrast) and luminance-specific components.     

Homocysteine and nitric oxide levels in plasma of patients with pseudoexfoliation syndrome,pseudoexfoliation glaucoma,and primary open-angle glaucoma

Purpose To evaluate plasma total homocysteine (tHcy) and nitric oxide (NO) marker levels in patients with pseudoexfoliation syndrome (PXS), pseudoexfoliation glaucoma (PXG), primary open-angle glaucoma (POAG), and normal controls.Methods This cross-sectional, prospective study involved 19 patients with POAG, 18 with PXS, 22 with PXG, and 20 control subjects. Fasting tHcy levels of all study participants were determined using a fluorescence polarization immunoassay method. Quantitation of total nitrate was based on the Griess reaction, in which a chromophore with a strong absorbance at 545 nm is formed by reaction of nitrite with a mixture of naphthylethylenediamine and sulphanilamide.Results The mean plasma homocysteine level was statistically significantly elevated in the PXS (p=0.033) and the PXG (p=0.023) groups but not in the POAG group (p=0.996) when compared with the control group. Multiple logistic regression analyses comparing the various patient groups with the single control group indicated that elevation in plasma homocysteine concentration was a significant risk factor for PXS (odds ratio per 1 mol/l increase in homocysteine concentration=2.05, 95% CI=1.19–3.52) and PXG (odds ratio per 1 mol/l increase in homocysteine concentration=1.36, 95% CI=1.00–1.85) but was not a significant risk factor for POAG (odds ratio per 1 mol/l increase in homocysteine concentration=0.99, 95% CI=0.78–1.26). NO markers levels were found to be slightly higher in PXS and PXG patients than control and POAG patients but the differences were not statistically significant (p=0.151). Multiple logistic regression analyses comparing the various patient groups with the single control group indicated that elevation in NO marker concentration was not a significant risk factor for PXS (odds ratio per 1 mol/l increase in NO concentration=1.00, 95% CI=0.99–1.01), PXG (odds ratio per 1 mol/l increase in NO concentration=1.00, 95% CI=0.99–1.00) and POAG (odds ratio per 1 mol/l increase in NO concentration=0.99, 95% CI=0.99–1.00). No statistically significant correlations were observed between plasma tHcy and NO markers in study groups (p>0.05).Conclusion Elevated levels of homocysteine in pseudoexfoliation patients with and without glaucoma may partly explain the increased risk of vascular disease among patients with pseudoexfoliation. No significant difference was found in plasma NO markers among the POAG, PXS, PXG, and the control subjects.     

The influence of ambient room lighting on the pattern electroretinogram (PERG)

It has been suggested that low ambient lighting conditions increase the amplitude of the PERG, but no data has been available on this issue. We recorded the transient PERG (0.8° check size) and steady-state PERG (15 rev/s, 0.8° and 16° check size) under three lighting conditions: dark room, only illuminated by the stimulus (resulting in 30 lux), our standard room lighting (windows occluded, one lighted lamp, 200 lux) and fully lit room (full ceiling illumination with eight fluorescent tubes) resulting in rather bright 2300 lux. The stimulus luminance was 50 cd/m². The sequence of lighting conditions varied for each subject and followed a balanced permutation of an ABCCBA scheme. Results showed a significant effect (P<0.01) across lighting conditions, with no relevant difference between the 30 and 200 lux conditions, but a reduction down to 70% at the 2300 lux condition. This obtained across all check sizes and temporal conditions. As an example, the transient PERG P50-amplitudes were as follows: dark, 5.6±0.8 V; medium, 5.3±0.6 V and bright, 3.8± V (mean ± SEM). Peak times decreased significantly with illumination (dark, medium or bright): 45.9±0.9, 43.1±0.6 or 40.8±0.8 ms. Contrast measurements quantitatively explained the noticeable reduction of PERG amplitude at the brightest illumination level simply by straylight, which reduced the display contrast. This suggests that bright sunlight should be excluded, and that lighting conditions should be moderately standardized at low or medium luminance levels for reproducible amplitudes and peak times.     

„Aberrante“ Ganglienzellen in der Wurzel des Nervus oculomotorius des Menschen

Zusammenfassung 56 Nn. oculomotorii von 37 Erwachsenen (mittleres Alter 66 Jahre) wurden untersucht. In 25 der 56 Nerven (44,6%) bzw. bei 19 der 37 Erwachsenen (51%) wurden insgesamt 243 Ganglienzellen in der Nervenwurzel gefunden. Der mittlere Durchmesser von 100 Zellen betrug 43.7 (range: 26,8–69,8 ; größte Frequenz bei 35–45 ). Histologisch ähneln sie den sensiblen Zellen eines Spinalganglions. Es wird die Frage aufgeworfen, ob es sich um aberrante Ganglienzellen oder ein Zellsystem handelt.Der Befund eines sensiblen Ganglion mit 46 Ganglienzellen im Verlauf des N. trochlearis wird erwähnt.

---

Aberrant ganglion cells in the human ocullomotor nerve

Summary 56 oculomotor nerves of 37 adult men (mean age 66 years) were examined. A total amount of 243 nerve cells were counted in 25 nerves (44.6%) that is to say in 19 men (51%). The mean diameter of 100 cells was 43.7 (range: 26.8–69.8 ,). The diameter of most of the cells fell between 35 to 45 . Histologically they look like sensory cells of a spinal ganglion. The question arises, whether these neurones represent aberrant cells or an independent neuronal grouping.The finding of a sensory ganglion in the course of the trochlear nerve with 46 nerve cells in it is mentioned.