Search Results - "International Ophthalmology"

1573-2630

choroid ; retina ; vascular permeability ; temperature control ; nutrition

Springer Online Journal Archives 1860-2000

Medicine

Abstract The choroidal vascular bed has many interesting features such as relatively wide but flat capillaries, fenestrated capillary walls and an enormous blood flow. The high flow rate results in a high oxygen tension in the tissue and is also of importance in the temperature control of the eye. The capillary wall is permeable to plasma proteins which is probably of great importance for the supply of vitamin A to the pigment epithelium. The permeability to low molecular weight substances is very high which results in a tissue fluid similar to plasma with respect to small molecules. It is not clear whether the choriocapillaris is normally reabsorbing fluid transported into the choroid from the retina and from the anterior chamber or if there is a net filtration from the choriocapillaris. Fluid can pass from the choroid through the suprachoroid into the episcleral tissues via the scleral substance and spaces around the blood vessels and nerves.

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1573-2630

lamina cribrosa ; vasculature ; scanning electron microscopy

Springer Online Journal Archives 1860-2000

Medicine

Abstract Vascular casts of the human lamina cribrosa region were studied in three autopsy specimens utilizing scanning electron microscopy (S.E.M.) in own modified technique. The lamina cribrosa is supplied from two major sources, the short posterior ciliary artery within the sclera and the distal optic nerve sheath pial vasculature. Recurrent choroidal arteries supplied a small number of centripetal branches to the lamina cribrosa. The central retinal artery did not give off centrifugal branches as it coursed through the lamina. The findings in these three human cases in three-dimensial visualization support other recent studies using serial histologic sectioning techniques. The photomicrographs are presented as a first successful images in S.E.M. for additional appreciation of the topographic morphology of radial arterioles.

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1573-2630

Springer Online Journal Archives 1860-2000

Medicine

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1573-2630

tarsal muscle (Müller's) ; levator palpebrae superioris muscle ; aponeurosis of the levator ; blepharoptosis

Springer Online Journal Archives 1860-2000

Medicine

Abstract Eight normal upper lids were examinated histologically with special regard to the aponeurosis of the levator and of the tarsal muscle (Müller's). The aponeurosis originates from the levator muscle within the orbit (behind the septum orbitale) and inserts at the upper anterior surface of the tarsal plate. The tarsal muscle originates from the levator muscle and inserts at the upper tarsal border. It is a smooth muscle containing many small blood vessels. Fifty-six specimens of tissue resected in operations for blepharoptosis were examined histologically. They consist of parts of the tarsal muscle and of the aponeurosis of the levator and of fat tissue without pathological changes.

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1573-2630

Springer Online Journal Archives 1860-2000

Medicine

Electronic Resource

1573-2630

retinoblastoma ; choroidal melanoma ; oncological teamwork

Springer Online Journal Archives 1860-2000

Medicine

Abstract Retinoblastoma and choroidal melanoma are two malignant ocular tumours that still give rise to discussions about diagnosis, natural history with respect to metastasis an choice of treatment. The therapeutic problems are best solved within a multidisciplinary oncology team in which the ophthalmologist, ophthalmopathologist and the general pathologist play an important role. In most institutes for ophthalmology a patient with a tumour in or in the region of the eye, is first seen by a specialist for eye diseases, who is also a surgeon in this field. In general the ophthalmologist decides on the diagnosis, the treatment and the follow-up without consulting other specialists in oncology. This solely ophthalmological approach can harbour a potential danger for the patient. Decisions on treatment made in a multidisciplinary team of specialists trained in oncological principles are responsible for the best results. Surgery combined with radiotherapy and chemotherapy can be a better choice than surgery alone, but even when surgery alone seems the best treatment, the discussion with the members of an oncological team can be of importance for the surgeon. The natural history of the tumour which includes the growth patterns, the growth rate and the tendency to metastasize may influence the choice of the surgical procedure; surgical intervention might be more or less extensive than previously foreseen. Dr. W.A. Manschot, professor in ophthalmic pathology, rightly advocates the contribution of the ophthalmopathologist to such an oncological team, because such a person has acquired knowledge in histopathology of the ocular tumours and experience in evaluating international literature in this field, the results of the treatment of groups of patients with the same tumour and publishing the statistically verified conclusions. As a chairman of the Dutch Eye and Orbit Tumour Committee Manschot was one of the enthousiastic initiators of its meetings of ophthalmologists, ophthalmic and orbital surgeons, radiotherapists, pathologists and medical oncologists. Two tumours have his special attention: the retinoblastoma and the choroidal melanoma.

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1573-2630

herpes simplex virus (HSV) ; herpes simplex keratitis (HSK) ; restriction enzyme analysis ; drug resistance

Springer Online Journal Archives 1860-2000

Medicine

Summary Restriction enzyme analysis was utilized to investigate 11 HSV isolates from patients with herpetic keratitis. The electrophoretic profiles of the DNAs indicate that the isolates belong to HSV-1 and are epidemiologically unrelated. Two of the isolates, derived from a patient with simultaneous bilateral herpetic keratitis were further characterized by genetic and phenotypic analyses. These studies showed the following: (i) the two recrudescent lesions were caused by the same HSV-1 isolate; (ii) the isolate yielded two different plaque phenotypes; (iii) these plaques showed different sensitivity to I.D.U.

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1573-2630

ceroid-lipofuscinosis ; amacrine cell ; horizontal cell

Springer Online Journal Archives 1860-2000

Medicine

Abstract Psychophysical examination of the visual performance of a patient with Kufs disease suggests abnormal functioning of the amacrine and horizontal cell systems of lateral inhibition. The sheep model offers insight into early patho-physiology of these cell types.

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1573-2630

peripheral ; retinal ; neovascularization ; diabetes mellitus

Springer Online Journal Archives 1860-2000

Medicine

Abstract The cases of seven patients with diabetes mellitus and peripheral proliferative retinopathy (retinal neovascularization at or anterior to the equator) were studied. Associated abnormalities found included systemic arterial hypertension in five, a positive fluorescent treponemal antibody titer in four, and benign monoclonal gammopathy, intravenous drug abuse and hemoglobin AS each in one patient. The presence of additional systemic diseases should be suspected in diabetic patients with predominantly peripheral proliferative retinopathy.

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1573-2630

Springer Online Journal Archives 1860-2000

Medicine

Abstract The treatment of the infant who is born with sensory deprivation amblyopia is one of the most difficult therapeutic problem sets facing the ophthalmologist today. This group of anomalies has many forms, the most common of which seems to be unilateral and bilateral cataracts. Substantial advances have been made, however, in many aspects of therapy for infants who have this set of problems. We have come to realize that it is essential to address these conditions at the first moment that is consistent with the safety of the child. New techniques in cataract extraction have reduced the time course of surgical treatment, reduced the frequency of secondary cataracts, and sustained the patency of the visual pathway. Unfortunately, practitioners who engage in the surgery may not have the back-up skills in advanced contact lens fitting, correction of aniseikonia, and, in some instances, the strabismological complications which are encountered. Further, improved means of assessment of visual acuity, binocular vision, and other visual characteristics of these infants are only in the developmental stages at this time. Thus, we propose to present the problem in an orderly manner. We shall first review the types of cases and problems. We will then discuss surgical techniques and the information which must be determined during examination under anesthesia (EUA) for the purposes of visual correction. We will then describe the designs of the spectacle lens and/or spectacle/contact lens combinations that are used to correct the resultant aniseikonia and anisometropia. We will address the approaches to patching and techniques on how to best achieve binocular vision in these patients. Separately, means and methods of assessment of vision by preferential looking, visual evoked response, optokinetic nystagmus, and tests of other visual functions will be explored. In summary, we will try to tie together the entire therapeutic regimen that can be used in the treatment of these patients.

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1573-2630

diabetic retinopathy ; cryoapplication ; cataract ; vitreous hemorrhage ; vitreo-retinal fibrosis

Springer Online Journal Archives 1860-2000

Medicine

Abstract Thirty-five patients with diabetic retinopathy were treated with cryoapplication. This was used as an alternative to Argon laser or Zenon photocoagulation because the media was opaque from vitreous hemorrhage or cataract. It was difficult or impossible to treat with photocoagulation. The clinical impression indicates that cryoapplication is effective, showing adequate pigmentation and chorioretinal scarring with regression of diabetic retinopathy changes. However patients with vitreo-retinal fibrosis became frequently worse weeks later. This is considered a contraindication. The use of cryoapplication in diabetic retinopathy is recommended in situations where the ocular media is not clear, such as vitreous hemorrhage and cataract. It can also be used if there is difficulty with laser photocoagulation following lens implantation. It may be valuable in some developing countries where photocoagulation is not available. Cryomachines are frequently used in eye camps. It is inexpensive and does not necessarily require electricity.

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1573-2630

corneal endothelium ; intraocular lens ; specular microscopy ; trauma

Springer Online Journal Archives 1860-2000

Medicine

Abstract In 1965 the patient, aged 6, sustained a perforating eye injury which was repaired and a traumatic cataract was aspirated within five weeks. Five years later a Ridley Mk 2 A/C intraocular lens was inserted. Several episodes of blunt trauma occurred over a three year period following this procedure. This paper reports the clinical, corneal pachometric and specular microscopic findings of both traumatized and normal fellow eyes 18 years after the initial incident. The corneal endothelial mosaic of the traumatized right eye was very irregular in the vicinity of the initial site of perforation. These marked variations in cell size and shape were less apparent at peripheral corneal areas. The estimated cell loss to the traumatized eye was in the region of 74% although in spite of this corneal function was maintained. The effects of trauma on the corneal endothelium are discussed and a brief review of the literature presented.

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1573-2630

secondary implantation after ICCE ; ECCE ; guide transportation suture ; guide transportation and fixation sutures ; iris tucking ; clinical situations ; anterior chamber implant ; posterior chamber implant ; Sodium hyaluronate ; Healon®

Springer Online Journal Archives 1860-2000

Medicine

Abstract The authors, after analyzing the different clinical situations where a secondary IOL implantation is indicated, describe 3 surgical techniques based on a common premise relying on the use of lens guide sutures for transportation or transportation and permanent fixation of the IOL's loops. The transportation sutures makes secondary implantation easier in anterior chamber lenses in technique I. The double purpose of transportation and permanent fixation at the angle permits a safe procedure with anterior chamber lenses in cases with no iris support in technique II and the possibility of sulcus or ciliary body fixation of a J type posterior chamber lens after ICCE in technique III.

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1573-2630

vernier acuity ; hyperacuity ; nuclear cataract ; posterior subcapsular cataract

Springer Online Journal Archives 1860-2000

Medicine

Abstract We have developed a new set of tests for evaluation of visual function through media opacities, based on vernier acuity measurements (hyperacuity). In this paper, results of one of these tests, the ‘gap test’, are compared in patients with posterior subcapsular (PSC) cataract versus nuclear cataract (NC). Patients with PSC cataract often report multiple images or significant ‘star burst’ effects. We hypothesized the presence of ‘multi-prismatic’ and/or high frequency spurious resolution phenomena due to PSC cataract characteristic substructure. We were able to minimize these effects by using 1) a pinhole held close to the eye, 2) a large (adapting) background field of white light superimposed on the vernier test targets, 3) a low-pass spatial filter applied to the targets. When the particular problems associated with PSC cataract are not present or are adequately addressed and when patients are matched for visual acuity, the hyperacuity ‘gap test’ shows less functional effect due to the opacity for PSC cataract than NC in all the cases we have tested. These findings, moreover, indicate that visual acuity provides an insufficient description of the effects of intraocular scattering on image formation. The results emphasize the importance and the necessity of developing models that better clarify the specific effects of different types of ocular media opacities.

Electronic Resource

1573-2630

perimetry ; automation ; spatially-adaptive program ; clinical applications ; SAPRO

Springer Online Journal Archives 1860-2000

Medicine

Abstract The SAPRO* program, devised for the OCTOPUS 201 automated perimeter, consists of a number of program components. It is designed to be used on the Octopus 201 computer. In its measurement mode, it employs an algorithm which achieves high speed and efficiency. This is made possible by a threshold bracketing strategy which is simpler than the normal OCTOPUS bracketing. Moreover, three grids with test location distributions of increasing resolution are superimposed in succession on the whole or on part of the visual field to be analyzed. Out of the distribution of test locations, only those which fulfill a number of criteria are actually utilized. These criteria must be given and are adaptable to any given clinical problem. As a result, despite the high spatial resolution achieved, only a fraction of the test locations are utilized using SAPRO as compared with a program using a fixed pattern of test locations. The algorithm is thus able to imitate human intelligence, which tends to concentrate stimuli at places which appear to be relevant for the solution of a problem. The results of program SAPRO are disturbed by short-and long-term fluctuations. Their validity is limited, in a manner similar to that encountered in any other threshold determination procedure. A number of printout modes is available which are oriented towards an optimal understanding of the information contained in various examinations. These principles will be illustrated by one case of inactive disseminated chorioretinitis.

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1573-2630

Springer Online Journal Archives 1860-2000

Medicine

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1573-2630

iridotomy ; Closed Angle Glaucoma ; N.D.: Yag laser ; Argon laser

Springer Online Journal Archives 1860-2000

Medicine

Abstract Performing a peripheral iridotomy with a ND Yag laser is a simple and efficient technique, with no side effects, no need for anaesthesia other than local and no surgical opening of the eye, with all the risks it entails. Out of 100 cases, 100% were a success from a technical point of view, and we observed no lesion of the lens which could have caused cataract. This out-patient technique, causing fewer complications than with Argon laser, can be used on any patient, whatever the age and the state of the angle, who has to be treated by peripheral iridotomy. The Neodymium Yag laser (ND: Yag) is a pulsed solid laser (1,2,3,8,29,31). It cuts tissues (photodisruption) by means of a shock-wave produced by optical breakdown (plasma formation). Its effect is different from that of the Argon laser which burns tissues (photocoagulation). The present study, of 100 cases, deals with the use of ND: Yag in peripheral iridotomies.

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1573-2630

Springer Online Journal Archives 1860-2000

Medicine

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1573-2630

Springer Online Journal Archives 1860-2000

Medicine

Electronic Resource

1573-2630

Springer Online Journal Archives 1860-2000

Medicine

Electronic Resource