摘要:

AbstractFluorophotometric measurements of vitreous and plasma fluorescence were performed in 14 normal subjects up to 24 h after injection of a single intravenous dose of sodium fluorescein. The data were subjected to a kinetic two‐compartmental analysis, including the determination of the transfer rate constants between the central and the peripheral compartment (K12and K21) as well as between the central and the vitreous compartment (Kinand Kout). In the central compartment (plasma) a mean terminal disposition rate constant (β) of free fluorescein of 0.23 h‐1was found, corresponding to a half‐life of 3.01 h. The vitreous fluorescence reached a maximum 2–5 h after the injection and then declined monoexponentially and very slowly (t1/2= 9.6 h). The rate constant of permeation into the eye (Kin) was found to be 0.66 h‐1, while the rate constant of elimination of fluorescein from the vitreous was 0.072 h‐1(Kout). Kinwas found to be significantly higher than K12, presumably indicating an active transport mechanism for fluorescein located at the blood‐ocular barrier. Koutwas significantly lower than K21, reflecting a slow vitreous elimination of fluorescein. A permeability index defined as the percentage ratio between the areas under the vitreous and the plasma concentration curves was found to be 3.5%, illustrating the poor penetration of fluorescein into the vitrous. Kinetic long‐term fluorophotometry appears to be a promising new tool in the study of the bloo

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1992.tb02134.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractNine normal and 24 diabetic subjects were examined by long‐term vitreous and plasma fluorescein fluorophotometry and the observed concentration profiles were described by biexponential time courses. The rate constant of elimination of fluorescein from the body (K10) was significantly decreased in diabetics with background and proliferative retinopathy, presumably caused by affection of the liver and possibly representing alterations in membranes of liver cells. Increased kidney albumin excretion was observed with increasing degree of retinopathy. The apparent rate constant of fluorescein penetration into the eye (Kin) was found significantly decreased in background as well as in proliferative retinopathy; while the permeability index, calculated as areas under vitreous and plasma fluorescein curves, was significantly increased. In the normal subjects Kinwas significantly higher than the rate constant of fluorescein transfer (K12) from the apparent central to the peripheral tissue compartment, whereas in the diabetics this difference was only found in the group with background retinopathy. The findings seem compatible with the concept that the breakdown of the blood‐ocular barrier could be caused at least partly by affection of an active transport system for fluorescein, but thickening and compositional changes of the basement membranes in the eye might also be of importa

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1992.tb02135.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractBoth eyes of twenty patients were treated for myopia with refractive keratectomy using an excimer laser (193 nm), and followed for six months. The 40 eyes were divided into Group I (22 eyes) with an attempted refraction change of 5–8 diopters; and Group I (18 eyes) with 9–12 diopters of attempted refraction change. In Group I the corrected visual acuity improved or was unchanged in 16/22 eyes. Two eyes with high preoperative corrected visual acuity had experienced a significant loss in corrected visual acuity after 6 months. In Group II, the corrected visual acuity decreased in 10/18 eyes, in 4 eyes significantly. Among the 40 eyes, 39 had a refraction change less than intended after 6 months. Overcorrection was seen in only 1 eye. In Group I, 20/22 eyes were corrected up to 2.5 diopters less than attempted. In Group II, 9/18 eyes were more than 2.5 diopters from the attempted correction. All eyes developed subepithelial opacification (‘haze’), which, in spite of steroid treatment, was still present after 6 months. The haze was more severe in eyes treated with 9–12 diopters of attempted refraction change. The achieved refraction change in the two eyes of the same patient was found to be correlated, possibly due to an individual factor in corneal woun

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1992.tb02136.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractStudies on critical frequency of photic driving were performed on patients with optic atrophy, moderately expressed suprachiasmal lesions and normal subjects. A reduction was present only in optic atrophy patients. The critical frequency of photic driving showed significant correlations with visual acuity and differential light sensitivity of the areas located within 15° from the fixation point. The correlation proved higher for foveal sensitivity expressed in non‐logarithmic rather than in logarithmic units, the opposite being the case for the sensitivity of parafoveal areas. It may be concluded that critical frequency of photic driving is conditioned by the cortical projection zones and visual pathways corresponding to the central 15° of the visual field, but with predominant role of foveal projecti

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1992.tb02137.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractWith a routine clinical colour vision test battery we found scotopization in 32% of retinal diseases presenting with pseudoprotanomaly as sign of an acquired type III blue‐yellow colour vision defect. In blue‐yellow colour vision defects of retinal origin scotopization is a transient phenomenon, present in early stages of the disease, but it is not an obligatory finding. There is no evident relationship between visual acuity and scotopizat

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1992.tb02138.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe diagnoses, according to type and site and the degree of visual impairment, responsible for severe visual impairment in children below the age of 18, were analyzed in a material compiled from the national registers of visually impaired in Denmark, Finland, Iceland and Norway. Among 2527 children the predominant causes of visual impairment are ascribed to congenital malformations, neuro‐ophthalmological diseases and retinal diseases. Optic atrophy is the leading single cause of severe visual impairment when all diagnoses are compared, and this also applies when all categories of visual impairment are included. Retinopathy of prematurity is the second principal cause of severe visual impairment, while cerebral amblyopia rates as the third most significant cause. Congenital cataract is also of considerable importance when all categories of visual impairment are compared. The differences registered between the Nordic countries were found to be within reasonable limits, except for a preponderance of neuro‐ophthalmological diseases in the Danish material. This could be explained by a better medical supervision of mentally retarded patients in Denmark. Additional impairments occur in a large percentage of patients, but are unevenly distributed in the disease groups. A high frequency of additional impairments are found in the neuro‐ophthalmological group and in the groups with congenital malformations, emphasizing the importance of a multidisciplinary evaluation when dealing with the visually impaired

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1992.tb02139.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA Nordic study group of ophthalmologists, NORDSYN, has compiled registers in Denmark, Finland, Iceland and Norway of 2527 visually impaired children aged 0–17 years. This paper is concerned with the sex‐distribution in the registers and has documented a statistically significant excess of males in two of the registers (Denmark and Finland). The dominance of males seems to be related to two main conditions: 1. Genetic factors. 2. Perinatal factors. The genetic factors are mainly concerned with X‐linked inheritance. The fact that perinatal influences involve visual impairment in males more than in females is difficult to account for. It may be conjectured, that the basis for perinatal visual damage is determined by unknown prenatal, possibly genetic, fa

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1992.tb02140.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe central visual function of 20 subjects with glaucoma‐like discs, normal intraocular pressures and normal visual fields and 20 age‐matched normal subjects was assessed by measuring contrast sensitivity using an oscilloscope technique. The subjects with glaucoma‐like discs exhibited a significant reduction in contrast sensitivity compared to the age‐matched normal; these differences were greatest at spatial frequencies of 2 and 4

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1992.tb02141.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA national epidemiological study revealed 1301 prevalent cases of retinitis pigmentosa (RP) in the Danish population on January 1, 1988. The corresponding number of 974 families were analyzed with respect to Mendelian inheritance groups. Thirty families, comprising 6.9% of the prevealent RP‐cases, were categorized with an autosomal dominant inheritance pattern. In 187 families, 22.6% of RP‐cases, autosomal recessive heredity was encounterted. X‐linked heredity was found in 45 families, 10.8% of the RP‐cases. Simplex RP‐cases comprised 562 persons (43.2% of RP‐cases). About a fourth of the non‐systemic X‐linked cases were females. Half of these had an age at onset after 30 years, but a third had their first RP‐symptoms before age 18 years. A representative fraction of parents to non‐systemic autosomal dominant, autosomal recessive, X‐linked, and simplex cases were evaluated concerning their age at the time they had their first affected child. Mothers of the male simplex cases were of statistically significant higher age than mothers of the other inheritance groups. This may imply a high rate of new mutations among simplex cases, especiall

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1992.tb02142.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractCystatins are widely distributed natural inhibitors of cysteine proteinase. They occur both intra and extracellularly in various cells and tissue fluids including tears. Using an immunofluorescence technique with antibodies against rat cystatin S, an inhibitor of submandibular gland origin, cystatin‐like immunoreactive material was demonstrated in the acinar cells of the exorbital lacrimal gland of the rat. Administration of the cholinergic agonist carbachol caused a depletion of cystatin from the acinar cells. This depletion was followed by a partial restitution in 6–8 h. Administration of the β‐adrenergic agonist isoproterenol for 4 days, which caused a marked hypertrophy of the submandibular gland, had no effect on the structure, weight, or cystatin content of the exorbital lacrimal gland. After such treatment, however, single large cells with intense staining for cystatin were encountered. Cystatin‐like immunoreactive material was also demonstrated in human lacrimal gland using antibodies against human cystatin S. These data suggest the notion that tear cystatins are secreted by the lacrima

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1992.tb02143.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY