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Biomedical subjects

A V Svirin

Publications and source records attributed to A V Svirin.

At least 19 recordsLinked to original sources
PubMed1990

[The morphological justification for the use of collagenoplasty in progressive myopia].

A morphological study in 20 rabbits was performed in order to investigate the response of the eye tissues and the changes in the collagen spongious preparations implanted into the episcleral space. Aseptic inflammation developing in the episcleral space was local and did not have influence on the state of the retina and choroid. The collagen implants underwent lysis, resorption and were gradually replaced by the connective tissue with the development of the episcleral scar that increased the thickness of the sclera from 1.5 to 2.5-fold during 1-2 months. These results are the basis for the successful surgical correction of the high progressing myopia.

Animals↗
PubMed1976

Early and late results of fascia lata transplantation in high myopia.

Transplantation of a strip of fascia lata to strengthen the posterior sclera in high progressive myopia was performed on 184 eyes of 108 patients with myopia ranging from 7 to 39 D. Three weeks after surgery visual acuity with correction had improved by 0-1 to 0-5 in 151 eyes (82 per cent) and refractive power had decreased by 1 to 8 D in 169 eyes (92 per cent). In 105 eyes (67 patients) that were followed-up for periods of from 1 to 9 years myopia increased in six by 0-5 to 3 D. In 29 patients who had an operation on only one eye and were then followed-up for periods of from 1 to 7 years the degree of myopia in the fellow eye increased by 1-5 to 6 D in 24 (83 per cent), and of the eyes that were operated on myopia increased by 0-5 to 3 D in only 5 (17 per cent).

Adolescent↗
PubMedDate not supplied

[Peripheral chorioretinal dystrophy and astigmatism of myopic eyes: statistical evaluation, relationship and clinical significance].

A clinically significant relationship between the myopic eye astigmatism and manifestation of peripheral chorioretinal dystrophies in them in young patients is described. A simple and effective method for predicting peripheral vascular chorioretinal dystrophies in myopic patients is proposed, based on the presence and severity of astigmatism. The incidence of various dystrophies in spherical and aspherical myopia is 32 and 78%, respectively. Dystrophies fraught with retinal detachment occur three times more often in astigmatic eyes, which are characterized by a more flat lens.

Adolescent↗
PubMedDate not supplied

[Comparison of clinical efficacy of trental various routes administration in hypoxic states of eye posterior segment].

Ninety-four patients with acute and chronic diseases of the posterior segment of the eye (optic nerve atrophy, central chorioretinal dystrophy, ischemic neuropathy, circulatory disorders in the central retinal artery and its branches) were examined. Clinical efficacy of various routes of administration of trental (intravenous, parabulbar, and by subtenon implantation of a collagen infusion system--SICIS) was evaluated in patients with ischemic states of the posterior segment of the eye. The most pronounced improvement of visual acuity was observed after administration through collagen infusion system. In acute and chronic hypoxic diseases of the posterior segment of the eye the time course of the rheographic coefficient was virtually the same after intravenous and parabulbar administration, while after SICIS the rheographic coefficient was significantly higher. Therefore, SICIS is the most effective method for trental administration in patients with acute and chronic diseases of the posterior segment of the eye; parabulbar administration ranks second in efficiency. This recommends SICIS as the most effective method for trental administration.

Blood Flow Velocity↗
PubMedDate not supplied

[A new operation in the treatment of refractory glaucoma: limbo-sclerectomy with valvular drainage of supraciliary space].

A new antiglaucoma operation has been developed: limbosclerectomy with valvular drainage of the supraciliary space. The operation was performed on 82 eyes with artiphakia, pseudophakia, and previously operated primary open-angle glaucoma. The patients were observed for 1.3 +/- 0.6 years after the intervention. Compensation of intraocular pressure and a significant increase in the coefficient of liquid discharge facility were observed in remote periods in all patients: in 95.1% patients without hypotensive therapy and in 4.9% cases instillations of 0.5% thimolol maleate twice a day were needed. Visual acuity and visual field borders did not appreciably change after the intervention. The operation is recommended for practice.

Adult↗
PubMedDate not supplied

[Effects of laser fragmentation of the lens mass on ocular tissues in experimental animals].

Side effects of laser on the posterior corneal epithelium and the retina during intracapsular YAG laser fragmentation of transparent lens fibers in various modes of laser operation were experimentally studied. The pulse power varied from 3 to 7.7 mJ, number of pulses from 55 to 160, length of exposure 10(-8) sec, diameter of the spot in the focus 30 microns. Animal eyes were enucleated on days 3-6 after the procedure. Posterior corneal epithelium was examined in the Hitachi scanning electron microscope, the retina in a light microscope. The findings evidence that injury to the posterior corneal epithelium in intracapsular YAG laser fragmentation of the lens depends mostly on the number of pulses and not on the exposure energy. A safe number of coagulates should not surpass 100, this being quite sufficient for fragmentation of the lens fibers at exposure power of 5-6 mJ. Such operation mode is safe for the retina as well, this recommending it for clinical use.

Animals↗
PubMedDate not supplied

[Method of lensectomy in high myopia].

The authors suggest a method of removing a transparent lens in high myopia patients aged over 40 with a dense lens nucleus. The method consists of 3 stages. Stage I consists in preliminary intracapsular YAG laser fragmentation of lenticular fibrils, performed 2-4 days before surgery. Stage II consists in YAG laser anterior capsulotomy directly before lens extraction. Stage III consists in lenticular mass aspiration irrigation via 2 small incisions on the cornea. The described lensectomy method was used in 23 patients (44 eyes) aged 40 to 55 with refraction of 16.0 to 23.0 diopters. The time of lenticular mass aspiration was cut down by half as against that after lensectomy without preliminary intracapsular YAG laser fragmentation of lenticular fibrils. No complications during or after surgery were recorded. After surgery vision acuity improved by 13 times without correction and two times with correction.

Adult↗
PubMedDate not supplied

[Drug therapy of progressive myopia].

To stabilize weak and medium-severity progressive myopia, instillations of cycloplegics (homatropin or tropicamid) and of hypotensive agents (clofelin or thymolol) were administered into the conjunctival cavity once a day (at bedtime). The course of treatment lasted 30 days and was repeated every 2-3 months. Complete stabilization of myopia was achieved in 65-58% of cases, as evidenced by a follow-up of 3 years, on an average. Incomplete stabilization of the condition was observed in 35-42% of patients, the annual progress gradient being above 0.15 diopters. Simultaneously an accumulation of the relative accommodation reserves was observed, by 38.3% on an average, and a resolution of asthenopia. In a reference group of 50 subjects (100 eyes) spontaneous stabilization took place in 27% of cases, the relative accommodation reserve being unchanged.

Adolescent↗
PubMedDate not supplied

[Statistical evaluation of the role of elevated intraocular pressure and weakened accommodation in progressive acquired myopia].

Ophthalmic tone was examined by Goldman's tonometry in 186 subjects (372 eyes) aged 13-35 with myopic and emmetropic refraction, as was the status of relative accommodation reserve. The findings evidence that in progressive myopia the mean level of intraocular pressure is by 3.0 mm Hg higher than ophthalmic tone in the eyes with emmetropic and stationary myopia; the relative accommodation reserve index was found decreased in 80-87 percent of patients with slowly and gradually progressing myopia, whereas in those with emmetropic and stationary myopia it was normal. This lead the authors to a conclusion that relatively elevated intraocular pressure (greater than or equal to 16 mm Hg, measured according to Goldman) and poor accommodation are factors indicating the risk of myopia progress and essentially influencing the refraction enhancement at this age.

Accommodation, Ocular↗
PubMedDate not supplied

[Collagen plastic surgery in progressive myopia].

The technique of surgery is as follows: 4 implants of wetted and squeezed out collagen sponge, 7-8 x 20-22 mm in size, 2-2.5 mm thick, are introduced into Tenon's space to fill the gaps between the rectus muscles; a standard sterile hemostatic sponge or a colocyl sponge in employed. Experimental studies have shown the development of new episcleral connective tissue at the sites where the sponge has been introduced, the thickness of this tissue exceeding 1.5-2.5-fold that of the rabbit sclera. Altogether 200 eyes (100 patients) with myopia of 3.5-15 diopters have been operated on. Myopia progress has been stopped in 95% of cases; vision acuity has improved by 0.14-0.15 (p less than 0.001), clinical refraction has reduced by 0.9-1.0 diopters (p less than 0.001) in 84% of patients. A significant improvement of the hemodynamics has been achieved, as well as of the eye membrane rigidity (1.5-2-fold). The complications were only negligible diplopia early after surgery in 3 cases. Collagen plastic surgery is a simple method, marked for the availability of the implanted material; it is highly effective and in fact does not involve complications, this permitting its use in progressive myopia of more than 4.0-5.0 diopters.

Adolescent↗