[Capabilities of remote laser homeostasis of the conjunctiva and sclera]. / Vozmozhnosti distantsionnogo lazernogo gemostaza kon"yunktivy i sklery.

INTRODUCTION: During some eye surgeries, a need for hemostasis can arise in order to prevent bleeding. PURPOSE: To determine the optimal settings for remote laser action of Nd:YAG laser with a wavelength of 1.44 µm on the conjunctival and episcleral vessels of the eye to stop bleeding, as well as for preemptive anemisation of tissue prior to performing a surgical incision. MATERIAL AND METHODS: The characteristics of the laser impact on vessels of the conjunctiva and sclera were studied clinically while conducting surgeries on 36 patients for cataract, glaucoma and excision of pterygium. RESULTS: The best mode of operation of Nd:YAG laser for remote laser anaemisation of the area of planned cut were 1.44 µm wavelength with 5 Hz frequency and energy of 100 mJ. Remote hemostasis can be achieved with the following settings for energy parameters: for pulse frequency of 5 Hz - pulse energy from 150 to 200 mJ; for pulse frequency of 10 Hz and 15 Hz - energy from 100 to 150 mJ; for pulse frequency of 25 Hz - energy not exceeding 100 mJ. CONCLUSION: No scar remained after the action of 1.44-µm Nd:YAG laser, and recanalization of individual vessels was possible.

[Morphologically reasonable application of 1.44 microm Nd:YAG laser in ocular surgery for distant hemostasis in conjunctival and episcleral vessels].

The article discusses morphological changes in bulbar conjunctiva and episclera after experimental exposure to Nd:YAG laser radiation at 1.44 pm in comparison to the effect of diathermal coagulator Mira TR4000. The results proved the use of 1.44 microm Nd:YAG laser in ocular surgery for distant hemostasis morphologically reasonable. Non-contact and directional laser treatment is more delicate as it produces smaller irradiated area. The depth of penetration and tissue heating is very limited. Neither excessive reparation, nor scarring is found in the exposed area. On the contrary, diathermy is a contact procedure associated with irregular distribution of heat, which causes large tissue burns and necrosis with subsequent adherent scar formation.

[Energy cataract surgery in diabetes mellitus].

The purpose of the investigation was to study and compare the results of laser extraction and ultrasound phacoemulsification of complicated cataract. The clinical material was presented by 154 eyes of 106 patients with diabetes mellitus. Laser cataract extraction was carried out on a Russian laser unit based on Nd:YAG laser at a wavelength of 1.44 microm. The investigation showed that laser extraction of complicated cataract in diabetic patients is an effective, safe, and sparing technique. Ultrasound biomicroscopy revealed a less pronounced ciliary body microvascular response and shorter regression of induced changes, and less loss of posterior corneal epitheliocytes in the laser extraction group than in the ultrasound phacoemulsification group, which is indicative of the advantage of laser technology of extraction of complicated cataract in patients with diabetes mellitus.

[The problems of cataract surgery and intraocular correction: Russian school achievements and modern trends].

The development of the safest and, at the same time, efficient methods of cataract surgery, is not only a topical task of medical science and practice, but also, taking the demographic situation into account, a solution to a social problem. The article describes the main achievements of academician S. N. Fyodorov's school in the field of cataract surgery with intraocular lense (IOL) implantation. Special attention is paid to the key components of cataract extraction technique named "small incision surgery", which is based upon the use of ultrasmall surgical approaches with self-sealing ability and no need for suturing. The main advantages and disadvantages of various types of cataract lense fragmentation, including ultrasound emulsification, mechanic and hydraulic fragmentation, and laser destruction, are described. Topical issues concerning cataract extraction technique under the conditions of complicating ophthalmopathology including the weakness of ciliary zonule system, high-degree myopia, glaucoma, pseudoexfoliative syndrome, small pupil, past injuries and eye surgery, are outlined. The paper also reflects a new qualitative step in the development of intraocular aphakia correction technique under modern conditions. Basic requirements to design parameters and IOL materials are determined from the position of reestablishing the accommodative function and fine visual functions. Ways of IOL design improvement are described especially for their application in non-standard and complicated cases.

[Optic coherent tomography in patients with immature cataract and pseudophakia].

Optic coherent tomography (OCT) was used to examine 14 persons (15 eyes) before and the following day after laser cataract extraction with intraocular lens implantation. There were slight, but statistically significant differences in the quantitative indicators of OCT in the eyes of immature cataract and pseudophakia (a reduction in the minimum retinal thickness in the foveolar area and that in the design volume of the macular area by the order of 1.4% of the baseline value). The above differences are likely to be largely due to the optic features of the pseudophakic eye; however, this suggestion needs further experimental and clinical studies.

[Development of a new technology of photodynamic destruction of newly formed corneal vessels via local administration of photosensitizers].

The purpose of the study was to perfect the procedure, based on the local administration of photosensitizers (PS) into the lumen of vascular trunks, for photodynamic destruction of newly formed corneal vessels. It was performed on 24 rabbits in which corneal intergrowth of newly formed vessels was induced, by applying nine No. 8.0 silk sutures. The vasculature formed 3 weeks later was represented as 20-35 large vascular trunks. A special microneedle, 200 microm in diameter, was designed for local administration of PS. Surgery was performed, by applying microsurgical techniques under an "Opton" operating microscope. The study showed the basic possibility of inserting the microneedle into the lumen of vascular trunks at the limbus with the subsequent filling of vessels with PS. It was sufficient for photodynamic effects to irradiate the cornea with light from the illumination lamp of an operating microscope throughout the operation (3-5 min). The most effective method for locally using PS involved its successive administration into 7-8 largest vascular trunks (the whole network was filled in by anastomoses in each case). The administration of PS into one large nutrient vessel was less effective due to the rapid flowing-out of PS from the vascular minor branches. Deuteroporphyrin sodium (dimegin) has a high photodynamic effect. The morphological basis of the effect is total endothelial destruction of newly formed vessels. The performed studies have demonstrated that the local administration of PS is as effective as the conventional technology of photodynamic therapy. The procedure is more adaptable to the problems of eye surgery due to the absence of systemic action on the patient's body.

[Cell loss in the posterior corneal epithelium after cataract extraction by Nd:YAG laser with wave length 1.44 mcm]. / Poteria kletok zadnego épiteliia rogovitsy posle khirurgii katarakty s ND:Yag-lazerom, imeiushchim dliny volny 1,44 mkm.

The purpose of the case study, as described in the paper, was to evaluate the cell loss in the corneal posterior epithelium (CPE) after laser cataract extraction (LCE) by means of a new laser unit designed on the basis of ND:YAG laser with a wave length of 1.44 microns. The conditions of 59 eyes with high (degrees 3-4) and extra high (degree 5) lens density were analyzed preoperatively and 3 months after LCE. Group 1 comprised 51 surgical cases, which were ideal in the technical respect; Group 2 comprised 8 surgical cases involving an intraoperative short-time lifting of the fragmentized lens mass into the eye anterior chamber during aspiration. The method of contactless endothelial biomicroscopy ("SP-1000" unit, "Topcon Co.", Japan) was made use of. According to the obtained results, it can be stated: the CPE cell loss made 1-9% (4.69 +/- 0.7%) and 1-18% (9.4 +/- 8.4%) in Groups 1 and 2, respectively. The total energy exposition level to laser radiation is the most significant factor affecting the CPE cell loss. The pulse energy radiation level did not affect the CPE cell loss. The corneal posterior surface was subject to a highly adverse impact in the fragmentation of brown cataracts. Finally, the results are indicative of an insignificant surgical trauma in LCE.

[Fluorescent angiographic evaluation of the iris microcirculation in cataract extraction by Nd:YAG laser with wavelength of 1.44 mcm]. / Fliuorestsentno-angiograficheskaia otsenka mikrotsirkuliatsii raduzhki pri ékstraktsii katarakty Nd:YAG-lazerom s dlinoi volny 1,44 MKM.

The purpose of the present study is to evaluate the iridial microcirculation by fluorescent iridial angiography after laser cataract extraction by using a new extraction device, i.e. "RAKOT", based on the Nd:YAG-laser with wave length of 1.44 mcm. 25 eyes (21 patients) aged 71 to 87 with mature senile cataract were examined. The method of laser cataract extraction was used in 14 cases. These eyes made up the main examination group. As for the controls (11 eyes), the manual technic of cataract extraction was used for them. The results in the main group show that the degree of the response of the iridial microvessels to surgery is insignificant and the microcirculation restores completely in 1.5-2 months after surgery provided there are no initial pathological changes in the iridial microcirculation (3 eyes). A short-time intensification of permeability of the iridial microcirculation is possible in eyes with a pronounced initial pathology in the iris (11 cases), however it restores to the original level during 3-3.5 months after surgery. The iridial microcirculation restores in the controls during 3 months after surgery. The described data demonstrate that the laser cataract extraction does not lead to pronounced iridial vascular disorders. A comparison with the controls is indicative of a lower trauma in case of laser method versus the manual technic of lens extraction.

[Laser extraction of brown cataracts with an Nd-YAG 1.44 mcm laser]. / Lazernaia ékstraktsiia burykh katarakt s Nd-YAG 1.44 mkm lazerom.

A total of 172 extractions of brown nucleus cataracts with maximum compactness were carried out using a RAKOT complex of devices, developed by the authors for laser extraction of compact nuclei and based on the use of Nd:YAG laser with a wavelength of 1.44 mu. Brown cataract was effectively destroyed at 200-250 mJ and pulse generation frequency 25 Hz within 9-12 min during the first 20 operations and 4-6 min during subsequent 152 operations. Five (2.9%) ruptures of the posterior capsule of the lens were detected. The cornea remained transparent on days 1-2 in 9 of 20 (45%) first operations and in 150 of 152 (98.6%) subsequent operations. A combination of common and heavy viscous elastic was used for the protection of the posterior surface of the cornea. The posterior capsule of the lens was protected by an original silicone thin plate. Loss of corneal epithelium in such a method of nucleus destruction is no more than 2-6%. Intraocular pressure is no higher than 21 mm Hg. If the coefficient of liquid discharge easiness is decreased before the intervention, intraocular pressure can increase during the early postoperative period. High visual acuity (0.7-1.0) was attained in 98% cases in the absence of concomitant retinal diseases. No complications which could be attributed to negative effect of laser on the eye were recorded during the remote period after the operation. The results indicate high efficiency and safety of laser extraction of cataracts.

[Clinical and morphological aspects of the state of the sclera in various types of genetically determined corneal changes]. / Kliniko-morfologicheskie aspekty sostoianiia sklery pri razlichnykh vidakh geneticheski obuslovlennykh izmenenii rogovitsy.

The authors analyze the results of a morphologic examination of 5 trephination scleral disks in various types of corneal curvature changes: with ectasia of the lower half of the cornea (1), with uneven corneal ectasia (1), with true keratoconus (2), and with keratoglobus (1), and come to a conclusion that involvement of the scleral connective tissue presenting as extracellular dysproteinosis is the morphologic substrate of deterioration of the elastic properties of the sclera, clinically observed in patients with various genetic corneal ectasias. Involvement of the sclera in the dystrophic process indicates a general involvement of the total external capsule of the eye in genetically determined corneal ectasias. The least marked changes presenting as fragmentation and fiber degeneration of collagen bundles are seen in uneven corneal ectasia. More profound changes in the sclera and its homogenization were detected in the patients with true keratoconus, ectasia of the lower half of the cornea, and keratoglobus.