Anterior chamber inflammation after transconjunctival cryosurgery

Background: Inflammation caused by transconjunctival cryotherapy for prophylactic retinal detachment surgery was measured in various conditions. Methods: Thirty-four eyes of 28 patients with peripheral retinal lesions predisposing to retinal detachment were studied by laser flare cell meter before and after treatment. Results: The mean flare value for 34 eyes was 4.06 ± 1.45 photon counts/ms before surgery and 5.72 ± 2.52 pc/ms after surgery (p < 0.05). Flare value was elevated at 1, 2, and 3 weeks after treatment, peaking at 2 weeks (p < 0.05), and normal again at 4 weeks. There were no significant differences in flare increase between eyes with and without retinal breaks, eyes with and without limited retinal detachment, eyes with myopia more and less than – 8.0 D, and eyes with a treatment area limited to one quadrant and extending over more than one quadrant. Conclusion: Transconjunctival cryosurgery caused mild inflammation in the anterior chamber of the eye for 3 weeks. The inflammation was not affected by the presence of retinal break or limited retinal detachment, the degree of myopia, or the extent of the treatment area.     

Interpretation of high-pass resolution perimetry with a probability plot

Background: The interpretation of high-pass resolution perimetry (HRP) fields can be difficult. An age-related probability plot was derived from a known data base to determine whether this improved specificity and sensitivity in early glaucoma detection Methods: Forty glaucoma patients with minor field loss and 40 normals of equivalent age and sex underwent HRP. All had previous Humphrey field data available for comparison. The detection of previously confirmed field defects by HRP was examined using different parameters. Results: Using the age-corrected 95% confidence levels gave the best results, with sensitivity of 82.5% (33/40) and specificity of 85% (34/40). Using the contour plot yielded lower sensitivity (67.5%), while subjectively eyeballing the ring printout gave higher sensitivity (90%), but led to poor specificity (72.5%). Conclusion: The use of a probability plot enhances the performance of HRP. A certain proportion of cases may be missed using one criterion alone, but combining the information with other indices can increase the yield.The authors have no proprietary interest in the equipment and technique described herein     

Precision of ultrasonic estimates of choroidal melanoma regression

Background: Important prognostic information may be gained from knowledge of the volume and, over time, the change in volume of intraocular tumours such as choroidal melanomas. Methods: The precision and time consumption of three different ultrasonographic methods were evaluated. Seven choroidal melanomas were analysed after placement of a ruthenium plaque and again after tumour regression had occurred. Perpendicular ultrasound B-scans were printed and analysed by overlay grid counting or outline tracing of tumour structures to calculate the volume. These two methods, using only two perpendicular scans, were compared with a micro-computer-controlled ultrasonographic three-dimensional rotation scanning system, where each tumour was manually outlined in 20 revolving scan planes. Results: The three-dimensional volume scanning method was the most precise, but also the most demanding in hardware and time consumption. Conclusion: Increased precision and less observer-dependent estimation of shrinkage rate after radiotherapy is available at the cost of sophisticated equipment.     

Ophthalmological and neuro-ophthalmological involvement in Churg-Strauss syndrome: a case report

Background: It is well known that different types of eye involvement may develop during the course of systemic vasculitides. Methods: We report here a case of Churg-Strauss syndrome (allergic granulomatous angiitis) characterized by the presence of multiple ophthalmological and neuro-ophthalmological lesions, i.e., mononeuritis of the fourth cranial nerve, multifocal choroidal ischaemia, and bilateral ischaemic optic neuropathy. Results: Ischaemic lesions in the posterior ciliary plexus and chorio-retinal circulation, which appeared simultaneously after a phase of disease activity, were documented. Conclusion: The simultaneous occurrence of multiple ocular features in a patient with Churg-Strauss syndrome suggests that regional vasculitis may be the pathological mechanism underlying the multiple ophthalmological lesions in this disorder.     

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.     

Effects of norfloxacin on the retina in rabbits

Background: Fluoroquinolones have a strong affinity with melanin, and their ocular effects have been reevaluated. Norfloxacin, one of the fluoroquinolones, has broad-spectrum activity against aerobic gram-positive and gram-negative bacteria. We examined the retinal toxicity and intraocular pharmacokinetics of intravitreal norfloxacin in rabbits. Methods: Twenty-three albino and 23 pigmented rabbits were divided into three groups to evaluate retinal toxicity and two groups to investigate the intraocular pharmacokinetics. Each of these five groups was further divided into two subgroups (albino rabbits and pigmented rabbits). Results: With 500 Etg norfloxacin, the oscillatory potential of the electroretinogram was transiently and selectively deteriorated in albino and pigmented rabbits, whereas the electroretinogram remained unchanged with 50 g in pigmented rabbits. No changes were observed in the visual evoked potential or on histology of the retina 7 days after an intravitreal injection of 50 or 500 ltg norfloxacin. The electroretinogram and the retinal histology became abnormal 7 days after four intravitreal injections of 500 g norfloxacin at 7-day intervals. As regards the intraocular pharmacokinetics after an intravitreal injection, the norfloxacin concentration in the chorioretina was as high as that in the vitreous 3 h after injection and was much higher than that in the vitreous 7 days after injection. Similar results were obtained after multiple injections. Conclusion: These results indicate a high concentration of norfloxacin in the melanin-containing ocular tissues.     

The effect of nasolacrimal occlusion on drug-induced mydriasis

Background: Nasolacrimal occlusion has been shown to improve the efficacy of some topically applied ocular drugs. The aim of this study was to investigate the effect of nasolacrimal occlusion on tropicamide-induced mydriasis. Methods: We compared pupillary dilatation by 0.125% tropicamide with and without nasolacrimal occlusion in 40 healthy volunteers. Results: Analysis of variance with repeated measures failed to show any advantage due to nasolacrimal occlusion in drug-induced mydriasis. Conclusion: Nasolacrimal occlusion did not increase the mydriasis obtained with 0.125% tropicamide.     

Integrins in human anterior chamber angle

Background: Integrins, which are composed of an and subunit, are capable of binding to a number of extracellular matrix proteins and, hence, affect cell adhesion and proliferation.Methods: The distribution of the integrin (₁, ₃-₅) and (_1–6 and _v) subunits in human anterior chamber angle was studied in eyes from subjects aged 9 months to 81 years using the indirect immunofluorescence technique.Results: Immunoreaction for the ₁ subunit was found throughout the trabecular meshwork (TM), in the cribriform layer, and in the endothelial lining of Schlemm's canal (SC). Labelling for the ₃ subunit was found in the TM and the cribriform layer only. In infant eyes the ₅ subunit was present in all three areas with the highest concentration in the cribriform layer, whereas no reaction was observed in adult eyes. The ₆ subunit was localized to the endothelium of SC only. Immunoreaction for the _v subunit was present in the TM and the cribriform layer of infants and young adults.Conclusion: The present results suggest the presence of several integrin heterodimers, acting as potential receptors for laminin, collagen, fibronectin, and vitronectin, in the anterior chamber angle.     

Relaxing incisions with compression sutures for control of astigmatism after penetrating keratoplasty

Background: Ten percent of patients with persisting postoperative astigmatism following penetrating keratoplasty (PK) require surgical re-intervention, despite an otherwise successful transplant. Relaxing incisions (RIs) in combination with compression sutures seem to be the preferable procedure. However, poor predictability and lack of long-term experience complicate the issue. Here we report the 2-year follow-up results of 25 patients with high PK astigmatism treated by means of RIs and compression sutures Methods: Commonly, free-handed RIs were placed at the graft-host interface and 10–0 nylon compression sutures were placed perpendicular to the incisions. PK sutures had been removed no less than 4 months prior to refractive surgery Results: Nineteen eyes regained a functional vision of >- 0.4. The net decrease in astigmatism was 6.1 ± 4.3 D (47 ± 21 %). The mean vector-corrected change in astigmatism was 13.1 ± 5.7 D. Cylinder axis variation was reasonably low, with a correlation of attempted versus achieved axis of r=0.85. Within the first 3 months after operation the induced astigmatism regressed by, on average, 5.5 ± 4.3 D, making intraoperative overcorrection necessary. As an inevitable side effect, refractive procedures resulted in a myopic shift (4.7 ± 6.9 D) in spherical equivalence Conclusion: RIs and compression sutures are very useful in reducing postkeratoplasty astigmatism if correction of extremely high cylinder (> 10 D) is not intended. However, predictability still remains unsatisfactory and more than one operation may be required.     

Hemoglobin exacerbates the ocular inflammatory response to endotoxin

Background: There is a clinical impression that bleeding into sites of inflammation exacerbates the inflammatory response. It has been hypothesized that hemoglobinic iron (Fe) contributes to this response by catalyzing free radical reactions. In the present study, the effects of autologous hemoglobin on the inflammatory response to endotoxin was determined. In addition, the possible contributions of Fe to this response was assessed by co-injection of either transferrin or desferrioxamine. Methods: A mild ocular inflammation was induced in rabbits by intravitreal injection of 0.25 ng endotoxin. In some animals apotransferrin, hemoglobin, hemoglobin + apotransferrin or hemoglobin + desferrioxamine were co-injected. Twenty-four hours later, anterior uveitis was quantified by slit-lamp examination and determination of protein concentration and infiltration of white cells into the aqueous humor. Results: Co-injection of autologous hemoglobin with endotoxin greatly exacerbated the ocular inflammatory response to endotoxin, especially the infiltration of white cells, which was increased 15-fold. Both apotransferrin, which binds Fe at high affinity, and desferrioxamine, which chelates Fe, greatly decreased the cellular response to the co-injection. Conclusions: It is likely that hemoglobinic Fe is responsible for the increased infiltration of white cells caused by the co-injection of autologous hemaglobin and endotoxin.     

Diclofenac sodium and cyclosporin A inhibit human lens epithelial cell proliferation in culture

Purpose: To investigate the effect of diclofenac sodium salt and cyclosporin A (CsA) on human lens epithelial cell (HLEC) growth in culture. Methods: Cultures of HLEC were obtained from anterior capsules from extracapsular cataract surgery. Third-passage cells were seeded in 96-well plates in 0.1 ml culture medium. Cytotoxicity was estimated by the tetrazolium test in confluent monolayers after 24 h exposure to a wide range of concentrations of diclofenac and CsA. The effect of subcytotoxic concentrations of diclofenac and CsA on HLEC proliferation in subconfluent cultures was evaluated after 24 and 72 h of exposure. To investigate the relationship between PGEZ synthesis and the inhibitory effect of these drugs, after 24 h of exposure to diclofenac and CsA the production of PGE₂ was measured by radioimmunoassay. We also tested the effect of exogenous PGE₂ addition to diclofenac 72-h-treated cultures. Results: Diclofenac and CsA (at concentrations 65 M and 2.5 M, respectively) inhibited the proliferation of subconfluent cultures of HLEC in a dose-dependent fashion. Diclofenac inhibits PGE₂ synthesis, while CsA at high doses stimulates PGE₂ synthesis of cultured HLEC. Exogenous PGE₂ addition reversed in part the inhibitory effect of diclofenac. Conclusions: Diclofenac and CsA at appropriate doses are effective in inhibiting cultured HLEC proliferation. This could be of interest to prevent posterior capsule opacification. Further in vivo experimental studies seem worthwhile.None of the authors have financial or proprietary interests in any of the products mentioned in this article     

Orthotopic corneal transplantation in the mouse — a new surgical technique with minimal endothelial cell loss

Background: The murine model of orthotopic perforating keratoplasty is important for studying the allograft reaction, but the small dimensions cause technical difficulties. Methods: The anterior chamber of the eye of the BALB/c mouse was measured with the confocal microscope and with histological methods. Ten C3H mouse donor corneas each were separated by the conventional technique and by the newly developed underwater technique, where the opened donor eye did not lose its shape under water. The corneal endothelium was stained with trypan blue and alizarin red S. Ten BALB/c (H-2d) mice received a corneal graft taken from a C3H (H-2k) mouse by the underwater technique. Results: The 3.7-mm eye of the BALB/c mouse has a corneal diameter of 3.5 mm. The cornea has a central thickness of 170 m, the epithelium comprising 30% and the stroma 70%. While none of the corneas separated by the new underwater technique evidenced endothelial damage, a 28 ± 17.0% defect of the endothelial surface was found with the conventional technique. All transplanted corneas were clear when the lids were opened on the 2 post-operative day and clouded between the 7th and 30th days (mean 16.5 days) due to an allograft reaction. Conclusion: The newly developed underwater technique is superior to the conventional technique, since floating of the very thin donor cornea during the separation procedure prevents endothelial defects by guarding against folds. By enabling reliable keratoplasty in the mouse, this technique facilitates studies on the experimental allograft reaction.     

Endophthalmitis after Lasiodiplodia theobromae corneal abscess

Background:Lasiodiplodia theobromae is an exceptional cause of human keratomycosis. Patient: We treated a 53-year-old man with fungal keratitis, which had been treated with topical betamethasone and gentamicin for 1 month, and endophthalmitis due toLasiodiplodia theobromae. Despite intensive systemic, topical and intravitreal fungicidal treatment, enucleation had to be performed. Results: The vitreous aspirate cultures were negative as of the second amphotericin intravitreal injection. However, histology revealed that the fungus was present in the cornea, ciliary body, iris and retina. Conclusion: The use of topical steroids may worsen the outcome of the infection.     

Normal heterophoric changes: 20 years' follow-up

Background: Evaluation of changes in the heterophoric condition of 100 normal individuals over a 20-year period. Methods: A reprospective study was undertaken. Charts of 100 normal men were reviewed. Individual changes in the heterophoric status were recorded over a 20-year period. The average value of the phoria at age 18–22 years was compared with the average value at age 34–38 years. Measurements were taken for near and distance fixation. No one was heterotropic. Changes in convergence and accommodation were also calculated. Results: A 0.9 ± 1.7 prism diopter increase in esophoria for distance fixation and a 0.6±2.5 prism diopter increase in exophoria for near fixation were found. These changes were statistically significant (P<0.001 andP<0.02 respectively). The near point of convergence receded by 0.5 ± 1.1 cm (P<0.001), and a decrease in accommodation over time of 2.8 ± 1.4 diopters was found (P<0.001). Conclusion: An increase in esophoria for distance fixation and a exophoria for near fixation was found in a 20-year follow-up of 100 normal subjects.     

Reattachment to a substrate prevents apoptosis of human retinal pigment epithelium

Background: Epithelial cells generally fail to survive in suspension. Harvesting human retinal pigment epithelium (RPE) for transplantation may separate the cells from their extracellular matrix and induce apoptosis. We investigated whether reattachment of RPE to a substrate will prevent apoptosis. Methods: Second-passage human RPE cells were plated onto tissue culture plastic precoated with extracellular matrix, fibronectin or laminin, uncoated tissue culture plastic, untreated plastic and untreated plastic coated with 4% agarose. Reattachment rates were determined for each substrate 24 h after plating. The TUNEL technique was used to determine apoptosis rates in attached cells, unattached cells and the entire cell population. Results: Attachment rates were as follows: ECM-coated tissue culture plastic fibronectin-coated tissue culture plastic laminin-coated tissue culture plastic uncoated tissue culture plastic untreated plastic agarose-coated untreated plastic. Apoptosis rates for the entire cell population increased as the RPE cell attachment rate decreased. The proportion of apoptotic cells in the entire population was inversely related to the percent attached cells (r = -0.95). Conclusion: Reattachment of harvested RPE to a substrate decreased the rate of RPE apoptosisin vitro. RPE cells which are removed from their substrate prior to transplantation must reattach rapidly to a substrate to prevent apoptosis.Presented in part at the Annual Meeting of the Association for Research in Vision and Ophthalmology, Fort Lauderdale, Florida, May 1996     

Corneal endothelial wound repair in normal and mitotically inhibited cultures

Background: The aim of the present study was to compare the morphology, proliferative activity and cytoskeletal organization of bovine corneal endothelial cells during wound healing under normal and mitotically inhibited conditions. Methods: Cell cultures were grown to confluency and incubated with the mitotic inhibitor 5-fluorouracil (5-FU; 2.5 g/ml) followed by a touch wound. Control cultures were maintained without 5-FU. Mitotic activity, F-actin, vinculin, vimentin and connexin 43 localization were evaluated before, during and after wound closure. Results: 5-FU inhibited irreversibly the mitotic activity of corneal endothelial cells during the whole wound healing process. In the presence of 5-FU, a high degree of polymegathism and delay in actin and vinculin redistribution to the cell borders after wound closure was observed. Vimentin and connexin 43 immunolabeling revealed only slight differences between 5-FU-treated and control cultures. Conclusion: Significant changes in cell geometry and cytoskeletal organization in the amitotic corneal endothelium became manifested only after wounding. These changes may influence cell-cell and cell-matrix interactions as well as functional restoration of the monolayer after wound closure.     

Plasma kinetics and antagonist activity of topical ocular timolol in elderly patients

Background: Systemic adverse effects of ocular timolol therapy are due to absorption of the drug from the eye into the systemic circulation. Elderly patients are frequently more susceptible to side effects than younger patients. This study was conducted to evaluate the plasma kinetics and antagonist activity of ocular timolol in elderly patients. Methods: Plasma kinetics and antagonist activity of timolol were studied in 12 patients scheduled for extracapsular cataract extraction and intraocular lens implantation. The patients received 40 l of 0.25% timolol into the lower cul-de-sacs of each eye. Blood samples were collected over a period of 12 h and plasma concentrations of timolol were analyzed using a radioreceptor assay. The corresponding ex vivo ₁- and ₂-receptor occupancies were calculated using radioligand binding techniques. Results: Timolol was absorbed rapidly into the systemic circulation and occupied on average up to 68% of ₁-receptors and up to 87% of ₂-receptors. The ₁- and ₂-receptor occupancy decreased slowly and was on average 38% and 64%, respectively, 12 h after the single dose. The calculated mean area under concentration-time curve of timolol in plasma was 10.28 ng/ml per hour and the mean half-life was 4.8 h. Both values were about twice as high as those found in healthy young volunteers following an intravenous 0.25-mg dose of timolol. Conclusions: In elderly patients the -receptor antagonist effect of ocular timolol after a single dose is strong and long-lasting. This finding may explain the frequent reported systemic side effects of ophthalmic timolol.     

Color Doppler imaging of the ocular vessels

Background: Color Doppler imaging allows for simultaneous two-dimensional anatomical imaging and Doppler evaluation of blood flow velocity. Methods: We examined 40 normal eyes (17 males and 23 females, aged 16 to 57 years) with this technique. The color Doppler unit used in this study had a 5.0-MHz PLF-503 ST phased-array scanning head. Each vessel examination was repeated 10 times during a single session. Results: The following peak flow velocities were found: central retinal artery, 12.5±2.4 cm/s; central retinal vein, 4.4±0.49 cm/s; posterior ciliary arteries, 14.4±2.6 cm/s; vorticose veins, 5.5±1.0 cm/s; ophthamic artery, 36.9±7.0 cm/s. Ophthalmic artery systolic and end-diastolic velocities declined as a function of age; however, these changes were not significant (systolic: r=–0.24; diastolic, r=–0.22). Conclusion: This noninvasive technique allows quantitative assessment of blood flow velocity in these vessels.     

Influence of oxygen free radicals and free radical scavengers on the growth behaviour and oxidative tissue damage of bovine retinal pigment epithelium cells in vitro

Purpose: This investigation was carried out to ascertain whether oxygen free radicals can influence the growth behaviour and consecutive lipid peroxidation of retinal pigment epithelium (RPE) cells in vitro and whether scavengers can counteract these effects. Methods: The experimental model was based on calf RPE cells. Hypoxanthine/xanthine oxidase (HX/XO) and superoxide dismutase/catalase (SOD/CAT) served as the radical generating system and scavengers, respectively. The components were tested alone and in combination. Lipid peroxides were determined in culture supernatants by a thiobarbituric acid assay. Results: Concentrations of up to 100 mol/1 of HX alone and 500/1000 U of XO alone, as well as the application of the scavengers without the radical generating system (HX/XO), had no effect. Doserelated reduction of cell growth and increase of lipid peroxidation were found with HX/XO treatment (single dose of 500 and 1000 U/ml 24 h after seeding). After application of 500 or 1000 U/ml of XO, CAT, when given alone (1200 U/ ml), counteracted the effect of the radicals on cell growth and lipid peroxidation; SOD (300 U/ml) had no effect. A combination of SOD and CAT was no better than the effect of CAT alone. Conclusion: The prevention of radical-induced reduction of cell growth and lipid peroxidation by scavengers supports trials of therapy using antioxidants and/or free radical scavengers for various ocular syndromes with RPE involvement.     

Collagen synthesis in lens epithelial cells on capsules containing intraocular lens implants in rabbits: immunolocalization of prolyl 4-hydroxylase

Background: We evaluated ultrastructurally the presence and distribution of lens epithelial cells and extracellular matrix on the posterior capsule after implantation of a silicone or a polymethylmethacrylate (PMMA) intraocular lens (IOL) in rabbits. The immunolocalization of prolyl 4-hydroxylase, an enzyme involved in procollagen synthesis, was also examined in such cells. Methods: Anesthetized adult albino rabbits (n=12) underwent phacoemulsification and aspiration (PEA) of the crystalline lens and implantation of a silicone or a PMMA IOL into the capsular bag of one eye. They were killed by an intravenous overdose of pentobarbital sodium. The lens capsules were processed for transmission electron microscopy and for immunohistochemical detection of the -subunit of prolyl 4-hydroxylase. Results: Ultrastructurally, lens epithelial cells on the posterior capsule evidenced an accumulation of collagenous extracellular matrix. Prolyl 4-hydroxylase immunoreactivity was detected in the cytoplasm of cells distributed on the capsules. Conclusion: Lens epithelial cells are involved in the production of collagenous matrix on lens capsules after PEA and implantation of IOL, resulting in a fibrotic process of the lens capsule.