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Purpose The relationship between supply and demand in health-care is a challenge. The purpose of the present study is to evaluate to what extent glaucoma prevalence is influenced by local access to eye health-care service in Norway. Methods Population-based cross-sectional study. Data from The Norwegian Prescription Database was used to find the number of users of topical glaucoma medication, grouped by age and county, giving an estimate of glaucoma prevalence. The number of registered ophthalmologists and opticians was obtained from The Norwegian Society of Ophthalmologists and The Norwegian Directorate of Health. Results In total, 75733 persons were treated with IOP-lowering drugs in Norway in 2018, suggesting an overall glaucoma prevalence of 1.43%. In the age group 70-89 years, the nationwide prevalence was 7.60%, the lowest prevalence being in Oppland (5.98%) and highest in Aust-Agder (9.28%) counties. The number of ophthalmologists per 100000 inhabitants varied from 2.63 to 14.65 in the various counties. A statistically significant correlation was found between glaucoma prevalence in the age group 70-89 years and access to ophthalmological services. Furthermore, the increase in glaucoma prevalence plateaus at roughly 10 ophthalmologists per 100000 inhabitants, indicating that this could cover population demands. This relationship did not apply for opticians. Conclusions There is a clear correlation between glaucoma prevalence and availability of ophthalmologists in various counties in Norway. Our study indicates a direct relationship between the number of ophthalmologists in the area and the number of people being treated for glaucoma, with prevalence plateauing once a threshold of approximately 10 ophthalmologists per 100000 inhabitants is reached. This finding suggests that low glaucoma prevalence in some regions could be due to limited access to ophthalmological services.

Background From a historical standpoint the epidemiology of exfoliation syndrome (XFS) is one of the most controversial subjects in ophthalmic literature. Current literature abounds with studies on the prevalence of XFS in various ethnic populations and clearly XFS is a common condition, but its true prevalence is difficult to ascertain. Overall, XFS is considered to be the most common identifiable cause of glaucoma worldwide. Purpose This review critically examines the published literature documenting the epidemiological features of XFS and attempts to provide a unified concept concerning existing controversy. Methods A critical review of selected literature pertaining to the epidemiology of XFS. Results It is well established that XFS and the ensuing exfoliative glaucoma have a worldwide prevalence and a progressively increasing age-related incidence. The prevalence of the condition is significantly underestimated. Many past studies have proposed clear geographic variations within and between ethnic groups. In contrast, there has also been some epidemiological evidence suggesting that the prevalence of XFS is similar within various ethnic groups. Published literature fails to address the potential role and impact of suspected exfoliation cases in the reported prevalence figures of the condition. Incidence figures for the condition are limited and vary extensively. Cumulative data have indicated that several, as yet partly understood genetic, ethnic, and environmental factors contribute to the varied prevalence of this condition. Conclusions Further understanding on XFS epidemiology is needed. Only a future large prospective study conducted by the same investigators, using similar methodologies for different ethnic populations will prove beyond doubt the hypothesis that significant geographic variations exist. Since patients with exfoliative glaucoma are at significant risk of losing vision it is vital to elucidate the causes and the risk of developing XFS. To reach this goal, it is important to better delineate the early changes of XFS and to focus research efforts on modifiable factors for XFS development.

Purpose Open-angle glaucoma (OAG) is a collective term for various subgroups of glaucoma of which primary open-angle glaucoma (POAG) and pseudoexfoliation glaucoma (PEG) are the most common. There is increasing evidence that both conditions have systemic ramifications. We wanted to examine to what extent lifespan and cause of death are influenced by POAG, pseudoexfoliation syndrome (PES), and PEG. Materials and methods Of 1864 people who underwent an eye examination in 1985–86, the presence of PES and/or glaucoma, along with date and cause of death were recorded. Based on information from the National Death Registry, the individuals were classified into the following groups of systemic diseases regarded as causing death: Cardiovascular disease (with two subgroups), cerebrovascular disease and neoplasms. Results All 1864 persons were followed to death, up to 30 years after examination. No difference in lifespan was observed when comparing OAG (i.e. POAG and PEG together) with the rest of the population. When adjusting for gender and age at inclusion, patients with POAG showed a reduced lifespan in the cardiovascular death group (2.44 years, p = 0.043). When comparing lifespan in the neoplastic group in the glaucoma patients, POAG and PEG, directly against each other, a mean age difference of 6.87 years (p = 0.017) was found. Conclusions POAG patients showed reduced lifespan due to neoplasia and cardiovascular disease. Persons with PES and PEG did not show these lifespan reductions. Our main conclusion is that POAG and PEG, the two main OAG subgroups, are very different disease entities both from an ocular and a systemic point of view., Primary open-angle glaucoma, pseudoexfoliation glaucoma, pseudoexfoliation syndrome, lifespan, systemic diseases

An ultraviolet (UV)-absorbing compound of unknown identity is present in the aqueous humor of geese and other birds flying at high altitudes. A goose aqueous humor extract, that was believed to contain the UV protective compound which was designated as “compound X”, was fractionated and examined using a variety of spectroscopic techniques including LC-MS and high field one- and two dimensional-NMR methods. A series of compounds were identified but none of them appeared to be the UV protective “compound X”. It may be that the level of the UV protective compound in goose aqueous humor is much less than the compounds identified in our investigation, or it may have been degraded by the isolation and chromatographic purification protocols used in our investigations.

Background: Pseudoexfoliation syndrome (PES) is a common eye condition, indicating a risk of various eye diseases. Whether or not PES has extra-ocular physiological or even pathophysiological implications has been a matter of controversy for years. Methods: In total 1888 persons were examined for PES in 1985–86. Of these, 1864 (98·7%) had died and were therefore available for analysis by 01.01.2016. Age and cause(s) of death were recorded. 9 diagnostic groups (cardiovascular disease, cerebrovascular disease, neoplasms, systemic hypertension, diabetes mellitus (DM), chronic obstructive pulmonary disease (COPD), Parkinson's disease, aortic aneurysm (AA), and amyloidosis) based on ICD-coding were analyzed for both a possible association between PES and lifespan, as well as PES and specific systemic diseases. Findings: In the cardiovascular group, PES was not associated with an alteration in longevity. The subgroups acute myocardial infarction and other cardiovascular diseases revealed significantly reduced and increased lifespan, respectively, compared to the rest of the population. These deviations were independent of PES. The impact of PES on the neoplasm group showed that PES-positive persons lived 1·81 years (p < 0·001) longer than PES-negative persons. No significant differences in the PES prevalence were found in any of the cause of death diagnostic groups. Interpretations: The present study suggests that lifespan reduction due to neoplasia is nullified by PES, and that this phenomenon is not restricted to one specific neoplasm type. Thus, the paradoxical conclusion emerges that PES provides a lifespan benefit to the patient with a neoplasm. For the remaining diagnostic groups, PES was neither associated with an altered lifespan, nor with any cause of death diagnoses.

Purpose To examine levels of oxidative DNA base damage and expression of selected genes and proteins related to DNA damage repair in human limbal epithelium engineered ex vivo. Methods Cells were expanded from limbal tissue on cell culture‐treated inserts in medium containing fetal bovine serum, recombinant growth factors, hormones and cholera toxin (COM) and in medium with human serum as the single growth‐promoting additive (HS). Cells were analysed after two, three and four weeks in culture for DNA strand breaks and oxidized purine bases (Comet assay using the enzyme formamidopyrimidine DNA glycosylase, Fpg) and for expression of DNA repair enzymes APE1, OGG1 and Polβ by in situ hybridization (ISH) and by immunohistochemistry (IHC). Results Levels of strand breaks were substantial while levels of net Fpg‐sensitive sites (8‐oxoguanine and ring‐opened FaPy bases) were relatively low in cells engineered in COM and in HS. Both types of medium were found to support expression of base excision repair (BER) enzymes APE1, OGG1 and Polβ at the gene level. At the protein level, expression of APE1 and OGG1 was noticeable in both conditions while expression of Polβ was low. Conclusion Our findings indicate low levels of oxidative stress and/or efficient DNA purine base damage repair in human limbal epithelium engineered in a medium with human serum as the single growth‐promoting additive as well as in traditional medium with xenobiotics.

An epidemiological eye study has been performed in three separate municipalities in the county of South-Trøndelag, Norway. The prevalence of pseudoexfoliation syndrome turned out to be 10.2%, 21.0%, and 19.6% in the respective areas, stating beyond doubt that there are considerable geographic variations in the distribution of this syndrome.

A 70-year-old man with a seronegative rheumatoid arthritis showed some peculiar lamellar crystalline deposits mainly at the Descement/endothelial level in both eyes. Serum protein analysis revealed a monoclonal gammopathy with increased amounts of IgG and K-light chains along with traces of the latter in the urine. Corneal biopsy was not available, but electron microscopy of the conjunctival specimen demonstrated crystalline deposits within the endoplasmic reticulum of plasma cells lying within the connective tissue. This material is supposed to be of protein nature. It seems reasonable that the conjunctival deposits are identical to those seen in the cornea by slit-lamp examination, and it is also suggested that they represents paraprotein aggregates. After treatment with melphalan (Alkeran) and prednisone systemically, the corneal deposits decreased over a period of 9 months with corresponding improvement of the visual acuity.

The aim of the study was to examine for possible differences between cell cultures derived from eye with and without pseudoexfoliation. In both populations, scanning electron microscopy showed flattened epithelial cells and also spindleshaped fibroblast-like cells. The presence of these cell types was further confirmed by immunohistochemical demonstration of cytokeratin and vimentin in the cultured cells. The cells maintained in vitro showed a linear increase in uptake of leucine during a 12-h period. Within this period, the leucine recovered in the TCA precipitable fraction was considerably higher than the non-bound fraction. In cultures maintained in medium with and without L-ascorbic acid, the presence of L-ascorbic acid significantly increase the uptake of leucine into TCA precipitable material, and to a similar extent in cultures from the two populations. In conclusion, cells derived from eyes with and without pseudoexfoliation material and maintained in vitro showed similar morphology, presence of intermediate filaments, as well as uptake of leucine under various culture conditions.

Knowledge of the probability of having glaucoma at different levels of eye pressure is a prerequisite for estimating at which eye pressure levels preventive pressure-lowering treatment ought to be applied. The glaucoma tolerance may not be the same in all population groups. Calculation of tolerance distribution curves may be performed if the frequency distribution curves of pressure in eyes with and without glaucoma are known. Regression analysis has been performed to compute curves approaching the cumulative frequency distribution of the eye pressure in different subgroups. Results of a population study including subjects greater than or equal to 65 years of age have been used. An equation describing an asymmetric sigmoid curve has been applied in the curve fitting procedure. The derivative of this equation was used to describe the noncumulative frequency distribution curves. The analysis has been performed in subgroups consisting of normal eyes, glaucomatous eyes, eyes with and without pseudo-exfoliation.

In this population-based screening study, dealing with 1941 persons above 64 years of age from three different municipalities, the overall open-angle glaucoma prevalence was found to be 8.3%. The prevalence in the separate areas (7.0%, 8.6%, and 9.5%) were not statistically different. Roughly 30% of the population with pseudo-exfoliation syndrome had glaucoma, and 4.2% had ocular hypertension, whereas the corresponding figures for those without pseudo-exfoliation were 4% and 0.8%, respectively. The high glaucoma rates are partly due to the high pseudo-exfoliation prevalence in the area. The prevalence of the capsular glaucoma increased towards a maximum between 75 and 79 years of age, whereafter the curve declined. This may indicate reduced survival time of glaucomatous patients.

On the basis of a glaucoma survey in a total population greater than or equal to 65 years of age, the IOP in eyes with and without pseudo-exfoliation (PE) has been compared. The average IOP was 22.2 mmHg in eyes with PE versus 17.4 in eyes without. The corresponding averages in eyes without glaucomatous damage were 18.6 and 17.1 mmHg, and in eyes with glaucoma 31.5 and 25.5 mmHg. The IOP elevation connected with the PE process was 4.8, 1.5, and 6.0 mmHg in the total, normal and glaucomatous population, respectively. The IOP frequency distribution curves of these 3 groups were compared. The right shift of the distribution curves of the PE groups was more pronounced at high pressure levels. The PE process seems to elevate the IOP particularly in eyes with a high IOP, which is in correspondence with hydrodynamical laws. At a certain IOP, the probability of having glaucomatous damage was higher in eyes with PE than in those without, indicating an increased vulnerability of PE eyes to an elevated IOP. PE may be a glaucoma risk factor also on its own, i.e. independent of the pressure elevation connected with this syndrome.

A white man aged 40 suffering from glaucomatocyclitic crises, was treated with trabeculectomy during an acute attack. The tissue specimen showed numerous mononuclear cells in the trabecular interspaces. The hypertensive attacks are supposed more to be due to blockage of the aqueous outflow pathway by these cells, and less to increased aqueous formation.

Spectrophotometry and spectrofluorimetry of bovine aqueous humour have been performed. The question of whether mechanisms for fluorescence quenching exist in the eye media was evaluated. It turned out that the marked fluorescence of tryptophane and protein was considerably quenched by the ascorbic acid, an observation not shown before. Thus, the aqueous humour minimizes UV-radiation to the lens in diurnal animals through three different mechanisms: 1) Absorption. 2) Fluorescence-quenching. 3) Fluorescence-mediated ray transformation of energy-rich short wavelengths to less potent longer wave-lengths. The impact of each of them is significantly influenced by the ascorbate concentration in the aqueous humour. The phenomenon of fluorescence-mediated ray transformation is, of course, per se independent of ascorbate, but the transformational input is significantly reduced due to ascorbate.

The probability of having glaucoma is indicated by the quotient (number of eyes with glaucoma)/(number of eyes in the total population). This quotient was calculated for each value of IOP. The number of eyes at each IOP value was taken from IOP frequency distribution curves for glaucomatous and normal eyes, calculated from values obtained by a population survey. By plotting the probability of having glaucoma vs IOP, a sigmoid curve was obtained. The curve indicates that while the glaucoma probability is near zero at IOP = 18 mmHg, it is 0.5 at 27–28 mmHg, and the probability approaches 1, i.e. certainty, at an IOP around 35 mmHg. The frequency distribution of the tolerance limit of IOP was calculated by derivation of this curve. The distribution of IOP tolerance limit was close to a normal distribution with average = 27.9 mmHg and standard deviation = 3.2 mmHg.

Samples of iris tissue were removed from human eyes with and without pseudoexfoliation syndrome and maintained in vitro for several weeks. The samples were cultured on tissue culture plastic as well as on biological basement membranes. The morphology of the cultures was examined by phase contrast-, scanning electron-, and transmission electron microscopy. Out-growth of cells with similar shapes was observed from normal iris as well as from pathological tissue on both type of substrate. In sections the outgrowing cells formed multilayered structures. In these areas the individual cells were separated by spaces containing extracellular material. The PE positive specimens revealed typical PE aggregates both within the native tissue and between the outgrown cells. Production of viable cell cultures from human eyes with pseudoexfoliation may facilitate the search for morphological and biochemical abnormalities in this syndrome.

Rabbit cornea epithelium was exposed to UV-radiation for 15 min from a distance of 50 cm, and specimens were studied after 1/2, 1, and 3 h, respectively. The following changes occurred: 1) Reduced number of the large impressions or the full-thickness holes of the superficial cells. 2) Partly rejected cells. 3) Numerous small plasma membrane defects. This investigation shows plasma membrane defects at an early stage after the exposure, and this may be the locus for the initial damage.

The distribution of ascorbic acid in the ciliary body has been demonstrated by means of a silver nitrate technique. It appeared that the basal cells in the pars plana region and in the valleys between the ciliary processes contain great amounts of ascorbic acid, in contrast to the basal cells over the processes proper which showed only traces. Rabbit and guinea pig revealed mainly the same findings, and quantitative differences occurred before and after intracardial injection of ascorbic acid. On the other hand, ascorbic acid was absent in the ciliary body of untreated rats, whereas only traces were found after intracardial injection of this substance. These species differences are in keeping with previous reports showing high concentration of ascorbic acid in the aqueous humour from rabbit/guinea pig, and no ascorbic acid at all in aqueous humour from rats.

A defect in the blood-retina barrier in the optic nerve head region has been demonstrated. In order to show the exact localization of this defect, an in vitro experiment has been performed on rabbit eyes, using horseradish peroxidase as a tracer. From a subretinal depot the tracer diffused between the innermost retinal pigment epithelial cell and the cells of Kuhnt intermediary tissue into the border tissue of Elschnig and the juxtapapillary choroid. The defect in the permeability barrier is thus located to the junction between the retinal pigment epithelium and the Kuhnt intermediary tissue. The role of the junctional complexes in the Kuhnt intermediary tissue in relation to the blood-retina barrier is discussed.

An electron micrcscopic study was performed on the trabecular meshwork of two monkeys (cercopithecus aethiops). Specimens from one animal revealed numerous cytoplasmic filaments of 45-65 A thickness in endothelial cells both on the trabeculae and in the wall of Schlemm’s canal after conventional glutaraldehyde and osmium fixation. Using a histochemical technique it was shown in specimens from the other animal that these filaments consist of actin material. This evidence of intracellular actin filaments in the trabecular endothelium indicates that these cells have contractile properties, and the possible significance of this finding for the regulation of outflow facility of aqueous humour is suggested.

The association between blood groups (ABO, Rh, Kell, Duffy) and pseudo-exfoliation syndrome, simple, and capsular glaucoma have been evaluated. The findings were: 1). No statistically significant abnormalities regarding blood group distribution in persons with pseudo-exfoliation syndrome. 2). In contrast to simple glaucoma, capsular glaucoma showed an abnormal distribution in the ABO- and the Kell-system. There was less glaucoma prevalence in the capsular A1-group compared to the O-group (p = 0.013), and less in the K1 negative group compared to the K1 positive one (p = 0.005). This trend was even escalated when combining the two systems: Among the K1 negative persons the glaucoma prevalence was lower in the A1-group compared to the O-group (p = 0.003). In the K1 negative group only 9 of 61 A1-persons developed glaucoma, in contrast to the K1 positive group where 4 of 4 A1-persons had glaucoma. This difference gave p = 0.00038, whereas the corresponding difference for the O-groups showed p = 0.65. It is concluded that once a person with blood group A1 has developed pseudo-exfoliation syndrome, the risk that capsular glaucoma will occur is about 7 times higher when that person is K1 positive compared to K1 negative. Perhaps this observation may be used as a prognostic factor for non-glaucomatous PE positive persons.

The results of a population-based (age greater than or equal to 65 years) examination of the frequency distribution of IOP are reported. 3726 eyes in 1887 individuals were included in the examination. By consistent use of conventional, well-defined criteria, glaucoma was diagnosed in 6.4% of the individual eyes. In the total material, the average IOP was 18.0 mmHg. Average IOP was 28.7 mmHg in eyes with glaucomatous damage, vs 17.2 mmHg in the normal eyes. Variance of IOP was much higher in the glaucoma group as compared with the normal group. The IOP frequency distribution curve did not fit with a Gaussian curve; it was asymmetric, skewed to the right. The distribution curve obtained by plotting the recorded frequencies was disturbed by irrelevant irregularities, both random and systematic. The irregularities could be evened out by the application of regression analysis, using the equation for the gamma distribution. The IOP frequency distribution is well represented by a gamma distribution curve. The fit is improved by excluding eyes with extremely high and low IOP.

Pseudoexfoliation syndrome is a risk factor in cataract surgery because of the increased weakness of zonular apparatus and reduced pupillary dilatation. The surgical outcome of using phacoemulsification in the central zone, inducing minimal stress on the zonules, inserting a capsular tension ring in selected cases, and stretching the pupil mechanically in eyes with miotic pupils, may turn out to be uneventful in most cases. Postoperative fibrosis with subsequent shrinkage of the capsule is increased in these eyes, and these centripetal forces will further loosen the zonular fibres. Late in-the-bag intraocular lens dislocation is therefore anticipated to become a growing problem in the future. Despite the dysfunctioning of the blood-aqueous barrier in eyes with pseudoexfoliation syndrome, the frequency of postoperative inflammatory reaction is low due to the improvements made in surgical technique and equipment in recent years. Glaucoma frequently occurs in eyes with pseudoexfoliation syndrome. Compared with primary open-angle glaucoma, optic damage is more pronounced in these eyes at the time of diagnosis and response to medical therapy is poorer. Although responses to argon laser therapy and filtering surgery are roughly similar between the two types of glaucoma, there are indications that primary laser trabeculoplasty has a higher success rate in pseudoexfoliation glaucoma than in primary open-angle glaucoma.

Purpose Ion channels are formed when acetylcholine (ACh) combines with specific receptors on the postsynaptic membrane. We are testing whether this occurs in vitro in corneal epithelial cells when exposed to ACh, using intracellular ascorbic acid (AA) as a tracer. Methods The corneal epithelium was separated from Bowman's membrane as an intact sheet with thermolysin (TL). These cells were incubated in a medium containing phospholine iodide (Phi) to block acetylcholinesterase (AChE) activity, and then, five different groups of specimens were examined: the basic level of ACh and AA in the cells was tested in groups I and II, respectively. In groups III-V, the culture medium was supplemented with AA, ACh and ACh+AA, respectively, and following 2 hr of incubation the cells were tested for AA. AA was determined by high-performance liquid chromatography (HPLC) with UV detection, and ACh by LC-MS/MS. Results The ACh concentration in the corneal epithelial cells was 23.7 ng/mg wet weight. AA values were as follows: preexposure 0.17 mg/g. After exposure to AA, ACh and ACh+AA, the values were 0.30, 0.12 and 0.21 mg/g, respectively. The AA concentration mechanism of the corneal epithelium was intact despite exposure to Phi and ACh. Conclusion The main observation is that the AA content of the corneal epithelium drops in response to ACh exposure. Various explanations are discussed, in particular the possibility that ACh exposure may cause cell membrane leakage through pores (nicotinic receptors). This would be similar to the moderate membrane leakage (depolarization) in neural synapses in response to ACh release. Interesting in vivo consequences may occur when considering that AChE is extremely UV sensitive, as this substance could be a target at which actinic radiation may influence the ACh-AChE complex in this epithelium.

Background To compare life span of persons with and without ocular pseudoexfoliation syndrome (PES). Methods The study is based on an epidemiological survey conducted in Sør-Trøndelag county, Norway, in 1985–86. All inhabitants over 64 years of age (2109 individuals) were invited. Mortality information was obtained from The Norwegian Institute of Public Health in 2014, by which time 99% of the participants were deceased. Results When adjusting for age and gender, life span was not statistically different in persons with and without PES. Following the diagnosis of PES, patients' survival was up to, and beyond, 30 years. Conclusions Our observations suggest that, despite all the systemic aberrations reported in persons with ocular PES, none or only marginal functional changes are caused in extraocular organs and tissues. The present study supports the notion that systemic PES is not a life-threatening condition., Highlights • Over the years several attempts have been made to link pseudoexfoliation syndrome to a number of serious systemic diseases. • The present study shows no difference in life span between persons with and without pseudoexfoliation in our cohort.

Objective: To evaluate the absorbance of ultraviolet radiation (UVR) in the aqueous humor of various animal species in relation to the ambient radiation of their respective habitats, and to identify substances responsible for this absorbance. Representatives of all five classes (fish, amphibian, reptile, bird, and mammal) have been tested. Methods: Absorbance was recorded using a spectrophotometer. The ascorbic and uric acid concentrations were determined by HPLC, and the amino acid profiles with an automatic analyzer. Screening for potential UV-absorbing substances was performed by HPLC and a total of 12 species were examined, 7 of them birds. Results: UV-absorbing substances in the aqueous humor were proteins, tryptophan, tyrosine and ascorbic and uric acid. In addition, an unknown UV-absorbing component present in bird aqueous humor caused a high, red-shifted UV-absorbance spectrum, particularly in tentatively heavily exposed species such as goose when migrating at 10,000 m altitude. By comparison, the UV absorbance above the 288-nm wavelength was low in the aqueous humor of fish, frogs, aquatic mammals and two ground-living birds. The crocodile, whose aqueous humor contained significant amounts of both ascorbic and uric acid, revealed a concentration mechanism for ascorbic acid. Conclusions: The UV absorbance of aqueous humor varies considerably from one species to the next, and independent of class. It is noteworthy that the species being at highest risk for high-dose UV exposure, the migrating goose, showed the most red-shifted spectrum.

Objective: A comparative study was performed in order to identify aqueous humor amino acids possibly involved in cataract formation in farmed Atlantic salmon. Methods: Aqueous humor amino acids from farmed salmons with and without cataract were compared with levels in wild salmon and other animals of different evolutionary levels such as frog, crocodile, turkey, goose, minke whale, and cattle. Serum samples from wild and farmed salmon and minke whale were also analyzed. Results: The total amino acid concentration was lower in aqueous humor obtained from salmon, frog and crocodile compared to birds and mammals. Wild salmon had a higher content of amino acids than farmed salmon. Asparagine was absent in salmon aqueous humor and serum. Aqueous humor proline was readily detectable in wild salmon, birds, whale, and cattle, but not detectable in farmed salmon, frog and crocodile. The aqueous humor concentration of taurine was about seven- and fifty-fold lower compared to serum in wild and farmed salmon, respectively. The corresponding ratio in minke whale was 1:2. Conclusions: The results indicate a blood- aqueous barrier for taurine in farmed salmon. The lower total amino acid concentration and low aqueous humor proline concentration in farmed salmon should be further investigated.

Purpose: (1) To evaluate the effect of ribonucleic acid (RNA) and ascorbate on UV-absorption and their impact on ultraviolet-induced (UV) fluorescence from various proteins, and (2) to compare RNA and DNA reduction of protein fluores- cence. These informations will be useful for later work on the UV-filtering effect of the corneal epithelium. Method Spectrophotometry and spectrofluorimetry. Results: (1) RNA and ascorbate caused a significant UV-absorption and reduced the fluorescence from various water-soluble proteins, the degree of reduction va- rying independently from one protein to the other. (2) RNA and DNA showed pro- tein fluorescence reduction of roughly the same order. Conclusion: The results are discussed both in the context of UV-protection of the cell nucleus in general, and the possible UV-filtering effect for the eye of bovine corneal epithelium. Key words: fluorescence - proteins - ascorbate - nucleic acids - ultraviolet radiation. Acta Ophthalrnol. Scand. 1997: 75: 496-498

100 outpatient and 143 inpatient intracapsular cataract extractions with anterior chamber lens implantation were examined 6 months post-operatively. 74 (74%) in the former and 107 (75%) in the latter achieved visual acuity greater than or equal to 0.5. Excluding non-surgical pathology, 93% in the outpatient group and 98% in the inpatient group had a visual acuity greater than or equal to 0.5 (P = 0.12). There were no significant differences in post-operative complications except for the incidence of cystoid macular edema. Six (6%) of the outpatient and 1 (0.7%) of the inpatient procedures had cystoid macular edema that resulted in a visual acuity below 0.5 (P = 0.02).

Reflex-free areas of the cornea endothelium are demonstrated by specular microscopy after heavy bilateral photokeratitis. The changes are believed to be caused by UV-radiation.

1) Pseudo-exfoliation syndrome (PE syndrome) is a condition with worldwide distribution. 2) Marked geographical variations have been demonstrated. 3) Environmental factors may be of etiological significance for the development of PE syndrome. 4) The PE syndrome's ability to promote glaucoma may vary from one area to another. 5) There seems to be a trend towards lower debut age of PE syndrome at lower latitudes. 6) More prevalence studies from different parts of the world are needed. A standardized set-up of such works would facilitate comparison of the results, and so some guidelines have been proposed.

Purpose: The short-term toxicological effects of two cyclosporine A eyedrop formulations are compared. Methods: Formula A was based on Sandimmune A (Novartis, Switzerland) infusion concentrate with a final ethanol concentration of 1% (w/w), and formula B on Sandimmune A oral solution. Both formulations were diluted in sterile peanut oil (10 mg/ml). The left eyes of 12 rabbits were treated with the cyclosporine eyedrops over a two-week period. The right eyes served as controls. Slit-lamp and scanning electron microscopic examinations were performed, and the total protein concentration in aqueous humor was measured in treated and control eyes. Results and Conclusion: Both Sandimmune oral solution and infusion concentrate-derived eyedrops were found to be non-toxic to rabbit eyes and there were no significant differences between the two formulations. More definite conclusions as to the safety of these cyclosporine formulations cannot be made without long-term trials.

Purpose: To study UV-absorption and UV-induced fluorescence in the bovinecorneal epithelium. Methods: Spectrophotometry and spectrofluorimetry. Results: The corneal epithelium absorbs UV-B radiation mainly owing to itscontent of protein, RNA, and ascorbate. Some of the absorbed energy is trans-formed to the less biotoxic UV-A radiation by fluorescence. RNA and ascorbatereduce tissue fluorescence. Conclusions: The corneal epithelium acts as a UV-filter, protecting internal eyestructures through three different mechanisms: (1) Absorption of UV-B roughlybelow 310 nm wavelength. (2) Fluorescence-mediated ray transformation tolonger wavelengths. (3) Fluorescence reduction. The extremely high ascorbateconcentration in the corneal epithelium has a key role in two of these processes. Key words: UV-radiation – ascorbic acid – RNA – corneal epithelium – fluorescence.Acta Ophthalmol. Scand. 1998: 76: 149–153 Copyrightc Acta Ophthalmol Scand 1998. ISSN 1395-3907 T he possible functions of ascorbate inthe anterior eye segment have longbeenthe subjectof discussion.It hasbeenproposed that it may protect the lensagainst damage due to superoxide (Var-ma et al. 1979), it may be involved in in-traocular pressure regulation by influ-encing the trabecular meshwork (Linne´r1964), or it may promote storage of cate-cholamines in the iris (Sears 1973).The significance of ascorbate for theabsorption of UV-radiation was pre-sented some years ago (Ringvold 1980),and two separate conclusions weredrawn: (1) The aqueous humour seems toact as a UV filter, mainly due to its highascorbate concentration. (2) High aque-ous ascorbate values are present only indiurnal animals. The latter observation,i.e. the environmental adaptation, waslater confirmed by Reiss et al. (1986).They suggested that in diurnal animalsascorbate may play a protective roleagainst light damage in general. The sig-nificance of ascorbate in the protection ofocular tissue was also demonstrated byLin et al. (1994), who concluded that‘‘high levels of ascorbate in the aqueoushumour of diurnal animals may protectthe lens against UV radiation underphysiological conditions’’. It is likewisenoteworthy that Andley et al. (1994)found the highest cytotoxicity in culteredlens epithelial cells at 297 nm exposure.This matches the observation that diur-nal aqueous provides an effective shieldfor the lens by absorbing just this and ad-jacent wavelengths (Ringvold 1980).A completely different UV-protectingmechanism has been proposed by Abedi-nia et al. (1990): Aldehyde dehydrogenasemakes up 20–40% of soluble protein inthe bovine cornea, and they indicatedthat this enzyme may serve a dual role infacilitating both the UV-absorption andthe disposal of cytotoxic byproducts gen-erated by this absorption.UV-absorption induces fluorescence inproteins and tryptophan. Because fluor-escence is likely to reduce optical qualityof the eye (Benedek 1971; Weale 1985; El-liott et al. 1993), there may be a need forminimizing this effect. Consequently, ithas been postulated that the ocular me-dia may be provided with fluorescence-re-ducing mechanisms, a hypothesis whichseems to be true for the aqueous humour(Ringvold 1996).The corneal epithelium is the eye struc-ture most heavily exposed to ambientshortwavelengths,indicatingtheneedforstrong protective mechanisms in thislayer. For this reason, and because thecorneal epithelium is easy to collect, thistissue was chosen for examination of UV-absorption and fluorescence-reducingmechanisms. The present study repre-sents an extension of previous work.Though conditions are more complex intissues than in biological fluids such asthe aqueous humour, it is reasonable touse similar methods.

Purpose To survey glaucoma epidemiology in Northern Europe. Results of literature review Open-angle glaucoma is defined here as the simple and capsular types taken together. On this basis open-angle glaucoma makes up by far the largest group of glaucoma in Northern Europe. These are the target groups of this study, and pigmentary glaucoma is excluded because of the small numbers. Conclusion Open-angle glaucoma is less frequent in Southern Sweden and Denmark than in Finland, Middle Sweden, Norway, and Iceland. This may to some extent be explained by the suggested low prevalence of pseudoexfoliation in the southern areas, but other factors are presumed to be of importance as well.

Journal homepage: http://www.int-res.com/journals/dao/ Osmotic cataracts were diagnosed in all of 191 Atlantic salmon Salmo salar L. postsmolts caught during 8 trawl hauls on the western side of the Vøringsplateau, Norwegian Sea, in June 2001. The changes varied from a hazy opacity in the anterior part of the lens to cataracts affecting the whole lens. Severely affected lenses appeared swollen and large vacuoles were visible in the opaque areas. Large vacuoles in otherwise clear lenses were diagnosed in 1 of 4 adult salmon examined. Histologically, widened sutures, acuolation of lens epithelium and cortex, and proteinaceous lakes subjacent to the epithelium were the most frequent changes, while extensive cortical necroses and epithelial proliferation were seen in a few cases. UV-absorbance of the aqueous humor was determined and levels compared to plasma levels and also to levels in farmed Atlantic salmon of the same developmental stage. Wild salmon generally showed higher levels of protective factors than farmed fish. The osmotic type of cataract diagnosed leads to poor vision and is a potential cause of reduced survival in postsmolts. The cause of the cataracts could not be determined, but defective osmoregulation is suspected.

PURPOSE: To evaluate whether prophylactic systemic ascorbic acid influences the average level of haze and the incidence of late onset corneal haze after photorefractive keratectomy (PRK). METHODS: Two consecutive groups of eyes treated with PRK for myopia with or without astigmatism were retrospectively compared. The patients had been treated similarly, with the exception that systemic ascorbate had been supplied orally in one of the groups. Haze intensity was quantified on a scale from 0 (clear cornea) to 4 (anterior chamber not visible). The diagnostic criterion for late onset corneal haze was a haze grade 2 or higher, occurring 4 to 12 months after surgery. RESULTS: One week, 1, 3, 6, and 12 months after surgery, the group without ascorbate (314 eyes) showed haze of average levels 0.61, 0.51, 0.50, 0.32, 0.10, respectively, and the group with ascorbate (201 eyes) showed haze of average levels 0.38, 0.18, 0.16, 0.09, 0.06, respectively. Comparison of the respective values showed a statistically significant difference between the two groups (P CONCLUSION: This retrospective nonrandomized clinical study suggests that oral ascorbic acid supplementation may have a prophylactic effect against haze development after PRK. However, routine prophylactic use of ascorbate can be recommended only after a randomized, prospective clinical trial substantiates its efficacy. [J Refract Surg 2003;19:338-343]

To investigate whether there is a role for ascorbic acid in the development of exfoliation syndrome (XFS).A case-control study was undertaken that included consecutive patients with and without XFS in whom cataract surgery was indicated. Patients with ophthalmic conditions other than XFS and conditions that may influence ascorbic acid levels were excluded.A prospective institutional study was undertaken. A small volume of aqueous humor was aspirated at the beginning of phacoemulsification cataract surgery. Eighty aqueous samples, 40 samples from 40 eyes of 40 cataract patients with XFS and 40 samples from 40 eyes of 40 age matched cataract patients without XFS, were collected and analyzed. Ascorbic acid concentration was evaluated in the aqueous samples with a microplate assay method.The mean +/- SD concentration of ascorbic acid in the aqueous from patients with XFS (0.86 +/- 0.43 mM; range, 0.12 to 1.7 mM) was significantly lower than the concentration of ascorbic acid found in the aqueous of age-matched control patients (1.15 +/- 0.50 mM; range 0.42 to 3.1 mM; P =.0068). Total mean protein concentration was found to be significantly higher in the XFS group (481.1 +/- 196.8 pg/dl versus 336.3 +/- 86.4 pg/dl in the controls; P.0001). Nevertheless, no correlation could be established between ascorbic level and protein concentration.A significantly reduced mean level of ascorbic acid was observed in the aqueous humor of patients with XFS. In view of the fact that ascorbic acid is a major protective factor against free radical action, a role for free radical action is possible in the pathobiology of XFS.

The hypothesis that ocular pseudo-exfoliation syndrome is part of a generalized disorder has been tested by suggesting that subjects having this syndrome would have increased mortality. However, no association was found between presence of ocular pseudo-exfoliation syndrome and mortality.

It has previously been suggested that the aqueous humour acts as a UV-filter protecting the structures behind. This hypothesis has here been further evaluated by use of spectrophotometry and spectrofluorimetry. Principally three different aspects of the protecting mechanism have been unveiled: absorption, fluorescence quenching and wavelength transformation. The extremely high ascorbate values obviously play a key role in all of them. Thus, aqueous ascorbate both increased absorption and suppressed fluorescence of radiation below roughly 310nm wavelength. In addition, as a consequence of ascorbate quenching, fluorescence emission to the UV-A range (320–400nm) is substantially reduced.

Conjunctival tissue was removed from eyes with and without pseudo-exfoliation material during cataract surgery. Cells derived from these samples were maintained in vitro. Confluent cultures were examined by transmission electron microscopy, and non-confluent as well as confluent cultures were examined for their ability to incorporate 3H-leucine and 3H-proline into TCA-precipitated material. Cells derived from both types of samples showed deposition of extracellular matrix, and a similar incorporation of the two amino acids. It is concluded that in vitro studies allow examination of basic metabolic patterns under varying conditions, and also a search for possible differences in such functions between tissues with and without production of pseudo-exfoliation material.

They seem to be correct when stating that the observation presented in item 3 has never been described before, and this makes them suggest this to be the most important finding in the study. They further ‘believe that these findings represent genuine channels, arising directly from the suprachoroidal space, communicating with the intrascleral venous plexus. In the first part these channels resembled a small ampulla, with a wide lumen and an uneven and striate inner surface. This configuration is similar to the collector channels emerging directly from Schlemm’s canal, i.e. relative wide where they arise at the canal (diameter 20-90 pm), with no adventitial tissue surrounding the channels, so that the endothelial lining directly abuts the collagenous lamellas of the sclera (Jacobiec 1982). An absence of perivascular adventitial tissue may explain the irregular and striate surface of the first part of the branches shown in our study, before they tapered into fine veins’. As seen above, those channels being lined by an endothelium are described in options 1 and 2. The present inquiry is related to item 3. The authors are in line with other reports (Hogan et al. 1971; Jacobiec 1982) when indicating that there is a continuous endothelial lining from the outer wall of Schlemm’s canal through the collector channels to the intrascleral vessels. On the other hand, to my knowledge, there is 2) Perforating bloodvessels, surFig. 1. One of the postulated aqueous channels connecting the suprachoroidal space and the intrascleral vessel plexus is visualized. Is there a transitional zone (arrow) somewhere along the channel from endothelial to non-endothelial coating of the wall? S=sclera; C =ciliary body; I = iris; Sc = Schelmm’s canal. (Courtesy of A. 0sterud).

Electrondense cell inclusions resembling lysosomes are described in macular human cone inner segments. The organelles were regularly localized just outside the external limiting membrane, and only one or very few of them were present in each cell. For the first time it is shown that these organelles drain their content into the intercellular space between the photoreceptors.

A previous observation of increased aqueous magnesium in eyes with senile cataract has been re-examined in a totally different material. The serum and aqueous level of calcium and magnesium from 34 patients with senile cataract were tested against comparable values from 4 patients with choroidal melanoma. In contrast to calcium, the magnesium aqueous/serum ratio was significantly higher in the cataract group. Possible explanations are suggested.