[Choroid and optical defocus]. / Khorioideya i opticheskii defokus.

The review summarizes experimental and clinical data attesting to the important role the choroid plays in the development of refraction through optically oriented thickness changes and the release of growth factors. Because of its unique anatomical position, the choroid can influence the transmission of a cascade of chemical signals from the retina to the sclera and thereby affect the growth of the eye. Understanding the relationship between the optical defocus and the response of the choroid to it will help uncover the fundamental mechanisms for controlling eye growth and develop new strategies for preventing the progression of myopia.

[Long-term results of perifocal defocus spectacle lens correction in children with progressive myopia]. / Otdalennye rezul'taty ochkovoi korrektsii s perifokal'nym defokusom u detei s progressiruiushchei miopiei.

Peripheral defocus plays a significant role in the formation of refraction. Perifocal spectacles allow differentiating correction of central and peripheral refraction of the eye along the horizontal meridian and can correct or reduce peripheral hyperopia. PURPOSE: To study the long-term results of wearing perifocal spectacles on the refraction in children with progressive myopia. MATERIAL AND METHODS: Perifocal spectacles were assigned to children of 7-14 years old with progressive myopia from -1.0 to -6.0 D in terms of refractive spherical equivalent. The children were examined before the prescription of perifocal spectacles and after 6 months, 12-18 months, 2 years, 3 years and 4-5 years. We measured visual acuity, the character of vision, refractive error before and after cycloplegia, performed biomicroscopy, ophthalmoscopy and biometry. Peripheral refraction was studied at 15° and 30° points in the nasal (N15 and N30) and temporal (T15 and T30) meridians without correction and while wearing perifocal spectacles. RESULTS: In perifocal spectacles, in the 15° zone, 100% of the eyes formed myopic defocus, which averaged -0.05±0.1 D in T15°, -0.25±0.16 D in N15° and -0.44±0.03 D in T30°. In the N30° zone, the hypermetropic defocus decreased by 4 times and amounted to 0.38±0.03 D. The rate of progression of myopia decreased from 0.8 D of baseline values to 0.17 D at 4-5 years of follow-up. After 6 months of wearing perifocal spectacles, the refraction gain was -0.2±0.02 D (in the control group it was -0.38±0.04 D), after 12-18 months - (-)0.38±0.04 D (-0.63±0.09 D in the control group), after 2 years - (-)0,78±0,06 D (-1.18±0,15 D in the control group), after 3 years - (-)0.99±0.12 D (-1.65±0.20D in the control group). During the 4-5 years of the follow-up, the refractive error in the main group was -1.16±0.2 D, which is 60% less than in the control group (-1.95±0.2 D). CONCLUSION: Constant wearing of perifocal spectacles reduces the rate of myopia progression in children by 4.5 times compared with the initial rate, and by 1.6 times (by 60%) in comparison with the control group. Perifocal spectacles are recommended as optical means to slow the progression of myopia.

[The influence of different means of myopia correction on peripheral refraction depending on the direction of gaze]. / Vliianie razlichnykh sredstv korrektsii miopii na perifericheskuiu refraktsiiu v zavisimosti ot napravleniia vzora.

INTRODUCTION: Peripheral defocus was experimentally found to control the development of refraction. PURPOSE: To evaluate peripheral refraction (PR) of myopic eyes in terms of different means of correction and the direction of gaze. MATERIAL AND METHODS: The study examined 128 patients (256 eyes) aged 8-14 years (average 11.07±0.39 years) with myopia from -1.0 to -7.0 (average -3.57±0.27 D). PR was measured without correction, in perifocal (PF), monofocal (MF), progressive glasses (PAL), monofocal soft contact lenses (ΜCL) and after orthokeratological (OCL) correction with the gaze directed straightforward or head angled outward, inward, upward and downward; all measurements were performed using binocular open-field auto ref/keratometer. RESULTS: PR profile without correction and with contact (OCL, ΜCL) correction does not depend on the direction of the gaze. In glasses, peripheral defocus is different with straightforward and skewed gaze directions. OCL forms a significant myopic defocus throughout the periphery of the retina. When using MCL, hyperopic defocus increases in all zones except the extreme temporal. In MF glasses, hyperopic defocus is formed and enhanced in all areas, significantly greater with skewed gaze than with straightforward. In PALs, myopic defocus is formed with gaze directed upward and downward, as well as at the extreme temporal periphery of the retina with straightforward gaze. In all other zones, hypermetropic defocus increases. In PF, in most zones myopic defocus is formed with all gaze directions. The greatest inhibitory effect on myopia progression is provided by OCL (YPR=0.28 D/year) and PF glasses (YPR=0.26 D/year). CONCLUSION: In contrast to correction with contact lenses, PR in glasses does depend on the direction of gaze. The inhibitory effect of the optics correlates with correction of hypermetropic defocus in myopic eyes.

[Objective parameters of accommodation in concomitant strabismus]. / Ob''ektivnye parametry akkomodatsii pri sodruzhestvennom kosoglazii.

PURPOSE: To develop an objective method of determining binocular accommodative response (AR) and concomitant accommodation in patients with strabismus. MATERIAL AND METHODS: The study included 34 patients (68 eyes) with concomitant horizontal strabismus aged 6 to 32 years. The parameters of accommodation were measured using open field Binocular Auto Ref/Keratometer Grand Seiko WR-5100K (Grand Seiko Co. Ltd., Japan). The prism was placed in front of the deviated eye or the prisms were distributed evenly in front of both eyes until the deviation was eliminated. RESULTS: The addition of prisms had no effect on the refractometry results. In convergent strabismus monocular, binocular, direct and consensual accommodation responses were significantly higher than in divergent: -2.15±0.1 D and -1.66±0.12 D; -2.13±0.09 D and -1.33±0.14 D; -2,04±0,15 D and -1,16±0,1 D; -1.97±0.15 D and -1.06±0.09 D, respectively. In divergent strabismus and myopia, the binocular response was 2.8 times higher than in hyperopia (-1.8±0.09 D and -0.63±0.04 D, respectively). Resting tonus of accommodation (RTA) value was higher in patients with hyperopia, both with convergent (mean -2.27±0.41 D) and divergent strabismus (-2.36±0.47 D). Minimal RTA was observed in patients with convergent strabismus and myopia (mean -0.75±0.1 D). CONCLUSION: The study resulted in the development of a method of objective accommodometry of strabismic patients with deviation eliminated by prisms. Monocular and binocular AR were significantly higher in convergent strabismus compared to divergent, where consensual accommodation of the squinting eye is significantly reduced compared to the paired one. In patients with consensual strabismus, RTA is significantly higher in hyperopia than in myopia regardless of the form of strabismus.

[АComparative analysis of the magnitude of the distance and lens-induced objective accommodative response in patients with different refraction]. / Sravnitel'nyi analiz velichiny distantnogo i lensindutsirovannogo ob''ektivnogo akkomodatsionnogo otveta pri razlichnoi refraktsii.

AIM: To study the magnitude of objective accommodative response (OAR) with account to the method of image defocusing. The latter can be realized by bringing the object nearer to the eye or by adding a minus lens in front of the viewer. MATERIAL AND METHODS: We examined 63 patients (126 eyes) with different refraction aged from 7 to 31 years. All patients underwent a series of OAR measurements on WR-5100K Grand Seiko Binocular Open-Field Autorefkeratometer under different conditions, including negative spherical lenses of -3.0 D and -5.0 D, test optotypes corresponding to visual acuity of 0.2 and 0.7 and presented at a distance of 5 m, and a set of variably sized optotypes presented at a distance of 33 cm and 20 cm. RESULTS: A disparity was found between the magnitude of accommodative responses evoked through different means: placing a negative lens in front of the viewer while he/she looks into the distance or bringing the object closer to the eye. In almost all cases lens-induced responses were less pronounced than distance-induced. In all myopic children, accommodative lag was longer at near than at distance. Generally, in all groups, OAR to distant objects as well as responses to a 3.0 D accommodative task at near did not depend on the size of the object. There was an insignificant and statistically unreliable difference for objects placed 20 cm away (5.0 D accommodative task): OAR to a smaller font was stronger than that to a larger one. CONCLUSION: In children and adults with emmetropia, hyperopic children, and myopic adults, longer accommodative lags were characteristic of lens-induced responses. In children with myopia, longer lags were observed at near. Moreover, at near, OAR to a smaller font was stronger than that to a larger one.

[Comparative evaluation of the effectiveness of various treatment modalities for accommodation disorders and acquired progressive myopia].

OBJECTIVE: To evaluate the effectiveness of non-surgical treatment of accommodation disorders and progressive myopia in children. MATERIAL AND METHODS: A total of 190 patients (380 eyes) with myopia aged from 6 to 18 years (10.79±0.18 years on average) were enrolled and divided into 9 groups depending on the treatment prescribed. RESULTS: Comparative evaluation of different hardware-based treatment modalities for progressive myopia allowed to work out their optimal combination: "Visotronic", "MACDEL 09", and magnetophoresis of Taufon 4%. Such courses, provided twice a year, were associated with optimization of accommodative response and 1.9-2.8 times reduction of the rate of myopia progression. On the contrary, pleoptic therapy showed a negative effect on accommodative tonus and the rate of progression of acquired myopia. CONCLUSIONS: Comparative evaluation of different hardware-based treatment modalities for progressive myopia and accommodation disorders allowed to work out their optimal combination: "Visotronic", "MACDEL 09" and magnetophoresis of Taufon 4%. This treatment, provided twice a year, allows to increase accommodative reserves and volume, improve objective accommodative response, and reduce accommodative hypertonus as well as the rate of myopia progression (1.9-2.8 times over a 1.5-year period). Under pleoptic therapy (specialized software, near field speckles, color pulse therapy, Ambliokor device), both accommodative tonus and the rate of myopia progression increased (1.3-1.5 and 1.6 times correspondingly).

[Peripheral refraction and retinal contour in children with myopia by results of refractometry and partial coherence interferometry].

OBJECTIVE: To determine the posterior pole contour of the eye based on the relative peripheral refractive error and relative eye length. MATERIAL AND METHODS: A parallel study was performed, which enrolled 38 children (76 eyes) with myopia from -1.25 to -10.82 diopters. The patients underwent peripheral refraction assessment with WR-5100K Binocular Auto Refractometer ("Grand Seiko", Japan) and partial coherence tomography with IOLMaster ("Carl Zeiss", Germany) for the relative eye length in areas located 15 and 30 degrees nasal and temporal from the central fovea along the horizontal meridian. RESULTS: In general, refractometry and interferometry showed high coincidence of defocus signs and values for the areas located 15 and 30 degrees nasal as well as 15 degrees temporal from the fovea. However, in 41% of patients defocus signs determined by the two methods mismatched in one or more areas. Most of the mismatch cases were mild myopia. CONCLUSION: We suppose that such a mismatch is caused by optical peculiarities of the anterior eye segment that have an impact on refractometry results.

[Differential diagnostic criteria of accommodative disorders].

A total of 150 patients (300 eyes) aged from 6 to 23 with myopia of different degrees were assessed to define differential diagnostic criteria of accommodative disorders such as accommodative insufficiency, habitual excess, and spasm. The patients were divided into 4 groups. Group 1 included 88 patients (175 eyes) with myopia from -0.75 to -8.5 diopters (general group), group 2-23 patients (46 eyes) with accommodative insufficiency, group 3-20 patients (39 eyes) with habitual accommodative excess, and group 4-20 patients (40 eyes) with accommodative spasm. In all cases subjective and objective parameters of accommodation were fully assessed and differential diagnostic criteria identified.

[Accomodation tonus in myopia and its potential prognostic value].

60 patients with different degree of myopia were examined to study habitual accomodation tonus (HAT) and accomodation rest tonus (ART). HAT was calculated as a difference between standard autorefratometer measurements before and after cycloplegia; HAT in open field (HAT-OF) was estimated using open-field autorefractometer before and after cycloplegia with a patient looking at the distant object; ART was considered as a difference between refraction in dark conditions (dark focus) and cycloplegic refraction using open-field autorefractometer Grand Seiko WR-5100K (Japan). In examined patients ART was maximal (-0,87 +/- 0,08 dpt) and HAT-OF-minimal (-0,15 +/- 0,04 dpt). The high values of accomodation tonus (both HAT and ART) were associated with higher rates of myopia progressing. For the first time dynamic refraction measured using open-field autorefractometer confirmed the phenomenon of "negative" accomodation.

[Objective accommodation parameters depending on accommodation task].

62 myopic patients were examined to study objective accommodation parameters in different conditions of accommodation stimulus presenting (use of convex lenses). Objective accommodation response (OAR) was studied using binocular open-field autorefractometer in different conditions of stimulus presenting: complete myopia correction and adding of convex lenses with increasing power from +1.0 till +3.0 D. In 88,5% of children and adolescents showed significant decrease of OAR for 1,5-2,75D in 3.0D stimulus. Additional correction with convex lenses with increasing power leads to further reduce of accommodation response. As a result induced dynamic refraction in eye-lens system is lower than accommodation task. Only addition of +2,5D lense approximates it to required index of -3.0D.

[On the contribution of cornea into accommodation of myopic eye].

To study the possibility of corneal contribution to process of accommodation in myopic eyes we examined 4 groups of patients: children and adolescents with low (1st group) to moderate (2nd group) myopia, young adults with moderate to high myopia after LASIK (3rd group) and PRK (4th group). Corneal optic power was measured using binocular open-field autoreferatometer in vertical and horizontal meridians for near (33 sm) and distant (5 m) fixation. No significant difference was found in children and adolescents with low and moderate myopia with intact cornea, as well as in young adults with moderate to high myopia after keratorefractive surgery. The optic corneal power tends to be moderately lower in horizontal meridian, but this difference is not significant. The revealed data do not support significant contribution of cornea into accommodation of the myopic eye.

[The distribution of bacterioplankton and mesozooplankton biomass in the White and Barents Seas coastal water]. / Osobennosti rasprostraneniia bakterio- i mezozooplanktona v pribrezhnykh vodakh Belogo i Barentseva morei.

The total population density and the biomass of bacterioplankton, mesozooplankton, and phosphate-accumulating bacteria (PAB) were estimated during the 2000-2001 summer-autumn seasons in the coastal waters of the White and Barents Seas, which are subjects to the action of tidal and sea currents, the inflow of riverine waters, and anthropogenic impact. In the shallow estuarine waters with salinities of 6.5-32@1000 near the Chernaya, Pesha, and Pechora River mouths, the population of PAB fluctuated from 0.1 to 9.1 million cells/ml (0-36% of the total bacterial population). In pelagic seawaters, which are low in phosphates (12-50 micrograms/l) and are characterized by an increased iron/phosphorus ratio (2.0-3.6), bacterioplankton amounted to 0.1-1.6 million cells/ml and was mainly represented by small organisms with a volume of 0.08-0.15 micron 3, commonly lacking intracellular polyphosphates. In the pelagic zone of the Barents Sea, the biomass of mesozooplankton (Bz) was comparable with that of bacterioplankton (Bb = 39-175 mg/m3), the Bb/Bz ratio being 1.4-4.6. Off the Varandeiskii, Pechora, and Kolguyev oil terminals, Bb increased to 155-300 mg/m3 and the Bb/Bz ratio rose to 1.4 to 50.3 (with an average value of 20.9), presumably due to the severe anthropogenic impact on these waters. In this case, the dense population of bacterioplankton (0.9-7.6 million cells/ml) was mainly represented by large cells (0.12-0.76 micron 3 in volume), most of which (3-43% of the total bacterioplankton population) contained polyphosphates. The chemical composition of these waters was characterized by an elevated content of the total phosphorus (65-128 micrograms/l) and by a low iron/phosphorus ratio (0.9-1.2).

[Determination of epsilon-caprolactam in food media by thin-layer chromatography]. / Opredelenie soderzhaniia epsilon-kaprolaktama v pishchevykh sredakh metodom tonkosloinoi khromatografii.

The method for thin-layer chromatography has been developed for determination of epsilon-caprolactam in food media: fats, dry products. The method sensitivity is 0.01 mg/kg (mg/1) for fats and 0,005 mg/kg for dry products. The method error is 20%. epsilon-Caprolactam was extracted from fats by water, from dry products by ethyl alcohol. The extracts were evaporated and chromatographed in a thin layer of silica gel. epsilon-Caprolactam was determined on the plates from the spot area. The method was used for hygienic evaluation of polyamide-6 film intended for packing fats and dry products.

[Gas-liquid chromatographic method of studying the migration into cheese of the volatile components of coatings based on aqueous polymer dispersions]. / Issledovanie metodom gazozhidkostnoi khromatografii migratsii v syr letuchikh komponentov pokrytii na osnove vodnykh dispersii polimerov.

The Moscow Technological Institute of meat packing and dairy industries has developed in cooperation with a number of branch institutes a technology for obtaining coatings based on aqueous dispersions of BXBD-65 (a copolymer of vinyl and vinylidenchloride) but butyl rubber which posses physico-chemical properties required to ensure biochemical processes attending maturing of the cheese. Gas-liquid chromatography showed that the diffusion of the solvent remnants occurs only in the layer of the cheese in immediate contact with its coating and in amounts below the permissible concentration. At the same time, it was found that vinylchloride was absent both in the coating and in the cheese enclosed in the coating.

[Hygienic properties of cellophane film intended for food packaging]. / K voprosu izucheniia gigienicheskikh svoistv tsellofanovoi plenki pishchevogo naznacheniia.

The cellophane films intended for wrapping food products were studied. Investigations have established the presence of these films of the cellulose xanthogenate and products of its decomposition, of carbon bisulphide in particular. With their joint presence the determination of carbon bisulphide and hydrogen sulphide was done colourimetrically, the sensitivity of this method being 0.005 mg/l. Migration of carbon bisulphide from the cellophane into the atmosphere and water was investivaged. An interconnection between the amount of the migrated carbon bisulphide and the odour of aqueous cellophane extracts was disclosed. To improve sanitary and chemical properties of cellophane a more intensive washing off of sulphur-containing compounds from it is recommended.