[Changes in the wavefront and peripheral defocus profile after excimer laser and orthokeratology corneal reshaping in myopia]. / Izmeneniya volnovogo fronta i profilya perifericheskogo defokusa posle eksimerlazernogo i ortokeratologicheskogo resheipinga rogovitsy pri miopii.

PURPOSE: This study compares the trends of changes in corneal asphericity, corneal and total aberrations and peripheral refraction in myopic eyes after excimer laser and orthokeratology correction. MATERIAL AND METHODS: Aberrometry (OPD-Scan III; Nidek, Japan) was performed in 63 patients (126 eyes) with moderate and high myopia before and after femtosecond laser-assisted in situ keratomileusis (Femto-LASIK; 88 eyes, group 1) and photorefractive keratectomy (PRK; 38 eyes, group 2). Peripheral refraction (Grand Seiko AutoRef/Keratometer) at 15° and 30° from the center of the fovea was observed in 12 patients of group 1 and in 18 patients with a background of orthokeratology correction (group 3). RESULTS: Corneal asphericity factor Q transitioned to positive values after PRK and Femto-LASIK. Corneal aberrations: root mean square higher order aberration (RMS HOA) increased in both groups, Tilt 1 increased in group 1 and became negative in group 2, Tilt 2 increased in group 2 and went negative in group 1. Trefoil 6 did not change in group 1 and decreased in group 2. Coma 7 and 8 increased synchronously in both groups. Spherical aberrations (SA) increased in group 1, and went negative in group 2. Total aberrations changed to a lower degree, and these changes were not synchronous with the corneal ones; RMS HOA decreased in group 1 (while corneal RMS increased significantly), and in the PRK group it increased, but much less than the corneal. Total SA increased in group 1 and did not change in group 2. Peripheral myopic defocus formed in all cases, after Femto-LASIK the maximum was in the zone of 30º, after orthokeratology lenses - in the zone of 15º. CONCLUSION: Using excimer laser and orthokeratology to reshape the cornea in full accordance with its different profiles have different effects on the wavefront and peripheral refraction of the eye. The internal optics of the eye partially compensates corneal aberrations induced by the excimer laser.

[Changes in subfoveal choroidal thickness in myopic children who wear bifocal soft contact lenses]. / Izmenenie tolshchiny khorioidei u detei s miopiei na fone nosheniya bifokal'nykh myagkikh kontaktnykh linz.

PURPOSE: To study the changes in subfoveal choroidal thickness in children with progressive myopia who have been wearing bifocal soft contact lenses (BSCL) with an ADD power of +4.0 D for 3 months. MATERIAL AND METHODS: The study included 40 patients (80 eyes) with progressive myopia of low and moderate degrees. The main group consisted of 23 patients aged 10.04±1.5 years with an average myopia of -3.06±1.17 D, they were examined before and 3 months after vision correction with bifocal soft contact lenses Prima BIO Bi-focal («OkVision Retail¼, Russia). The control group consisted of 17 patients (34 eyes) aged 9.29±0.92 years with an average myopia of -3.05±1.5 D using single vision spectacle lenses. Cycloplegic refraction, choroidal thickness and axial length were measured in all patients before and after 3 months. Choroidal thickness was measured using the semi-automatic method on the optical coherent tomography system RS-3000 Advance 2 («Nidek¼, Japan). Axial length was measured using the optical biometer IOL Master 500 («Carl Zeiss¼, Germany). RESULTS: In the main group, subfoveolar choroidal thickness increased on average by 15.3±24.3 µm after 3 months of wearing BSCL, and in the control group it decreased on average by 9.03±28.65 µm. Comparison of changes in choroidal thickness between the main and the control groups revealed a significant difference (p<0.001). Increase in axial length of the eye in the main group was significantly less than in the control group (0.005±0.08 mm vs 0.07±0.06 mm; p<0.001). A strong negative correlation was found between changes in the axial length and subfoveolar choroidal thickness in the main group (r= -0.67), but no similar relationship was found in the control group (r= -0.13). CONCLUSION: Subfoveolar choroidal thickness increases in children wearing bifocal soft contact lenses for myopia correction.

[Correlation of chorioretinal parameters with anatomical, optical and functional indicators of eyes with amblyopia of various origins]. / Korrelyatsiya khorioretinal'nykh parametrov s anatomo-opticheskimi i funktsional'nymi pokazatelyami pri ambliopii razlichnogo geneza.

Purpose. To measure thickness of the central retina and choroid, retinal nerve fiber layer and ganglion cell complex in the macular region, retinal nerve fiber layer in the peripapillary region in eyes with various types of amblyopia, and to analyze its relationship with best corrected visual acuity, refraction and axial eye length. MATERIAL AND METHODS: The study included 50 patients aged 5 to 16 years (mean age 10.04±3.01 years). All patients were divided into 6 groups: 1 - relative amblyopia with congenital myopia (23 eyes); 2 - dysbinocular amblyopia (14 eyes); 3 - refractive amblyopia (16 eyes); 4 - anisometropic amblyopia (7 eyes); 5 - paired eyes of patients with amblyopia (20 eyes); 6 - control group (20 eyes). Chorioretinal parameters were determined using the RS-3000 Advance 2 spectral optical coherence tomography system («Nidek¼, Japan). Correlation analysis was performed using the Pearson's linear correlation coefficient (r). The level of significance of the differences was determined by the standard Student's t-test. RESULTS: Morphological changes in the sensory and choroid membranes of the eye were revealed in groups with amblyopia of various origins compared to the control group, as well as in the fellow eyes. Intergroup comparison showed the presence of more significant disorders in refractive and relative amblyopia due to congenital myopia. Correlation analysis showed that structural changes in the posterior pole are more related to the anatomical and optical parameters of the eyes. CONCLUSION: Optical coherence tomography allows detection of microscopic structural anomalies in the posterior pole of the eye in amblyopia of various origins, assists in differential diagnosis of this condition with organic pathology, and - most importantly - helps peer deeper into the pathogenesis of this disease.

[Use of optical coherence tomography angiography in assessment in conjunctival vascular architecture in health and pathology]. / Vozmozhnosti opticheskoi kogerentnoi tomografii v angiorezhime v otsenke angioarkhitektoniki kon"yunktivy v norme i pri patologii.

PURPOSE: Investigation of the capabilities of anterior segment (AS) optical coherence tomography angiography (OCTA) in evaluation of conjunctival vascular architecture in healthy individuals and in various pathological conditions. MATERIAL AND METHODS: The study included 17 healthy volunteers (34 eyes; the control group) and 62 patients (68 eyes) with conjunctival lesions of various nature. All participants underwent AS-OCT and AS-OCTA with assessment of qualitative (vessels pattern, lumen, pathologic tortuosity) and quantitative parameters (vessel density (VD, %) in the lesion area). Mean VD (MVD) and local VD (LVD) were determined, as well as VD in perifocal tissues (PVD). RESULTS: OCTA scans in 8 conjunctival sectors showed mostly radial pattern of the vascular architecture, with vessel lumen remaining the same over their entire visible length. Larger-sized vessels in deeper conjunctival layers were discovered in most cases. The lowest VD value (33.3%) was registered in the superotemporal quadrant, and the highest (38.9%) - in the nasal. Tortuosity of the vessels with course disruption, uneven lumen over the length of the vessels and increase in VD were observed in the area of conjunctival lesions in all cases excluding congenital abnormalities, pingueculae and conjunctival melanocytic intraepithelial neoplasia. The malignant nature of the tumors was indicated by dense vessel distribution and difficulties for visualization of intravascular space, and confirmed by pathohistological analysis. An increase in the number of areas with a lace-like pattern was characteristic for melanomas, with mean VD of more than 50% in the most vascularized areas. CONCLUSION: AS-OCTA is an informative method for the visualization of vessels in healthy conjunctiva and in conjunctival pathology. Local VD in the lesion area should be measured when the vessels are unevenly distributed.

[Gyrate atrophy of the choroid and retina with ornithinemia and foveoschisis (clinical observation)]. / Atrofiya girate khorioidei i setchatki s ornitinemiei i foveoshizisom (klinicheskoe nablyudenie).

Gyrate chorioretinal atrophy (GCA) is a rare hereditary disease with certain complications; one extremely rare complication of GCA is foveoschisis. For the first time in Russian ophthalmology, a 10-year-old female child has been described to have genetically verified GCA associated with the OAT gene in combination with ornithinemia and foveoschisis. The diagnosis was made on the basis of fundus examination, perimetry data, autofluorescence, optical coherence tomography, fluorescence angiography, electroretinography, mass spectrometry with confirmation by molecular genetic research. The presented clinical case illustrates the need for an interdisciplinary approach to the diagnosis of GCA with diagnostic algorithm involving various examination methods and doctors of different specialties.

[Correlations between visual fixation parameters, photosensitivity of the retina and visual acuity in various types of amblyopia]. / Vzaimosvyaz' parametrov zritel'noi fiksatsii, svetochuvstvitel'nosti setchatki i ostroty zreniya pri razlichnykh vidakh ambliopii.

PURPOSE: To study the parameters of visual fixation, photosensitivity in the macular region of the retina, and their correlation with the best-corrected visual acuity (BCVA) for various types of amblyopia. MATERIAL AND METHODS: The study included 50 patients with an average age of 11.02±4.2 years. All patients were divided into 3 groups depending on amblyopia type; group 4 consisted of the paired eyes of patients with amblyopia; group 5 was the control group. Retinal photosensitivity and fixation parameters were studied on the Nidek MP-3 microperimeter (Japan). Correlation analysis was performed using the linear Pearson correlation coefficient (r). RESULTS: Retinal photosensitivity was the lowest in the groups with relative amblyopia with nystagmus (25.7±3.6 dB; group 3) and congenital myopia (26.1±2.9 dB; group 2), which is consistent with the partially organic nature of relative amblyopia. In the group with strabismic and refractive amblyopia (group 1), photosensitivity did not significantly differ from the control group (p>0.05). Fixation density was the lowest in the first (85.1±0.2% and 92.8±0.16% at 2° and 4°, respectively) and the third (62.6±0.16% and 89.3±0.05% in 2° and 4°, respectively) groups. In the first group, a strong correlation (r=0.77) of the fixation density and BCVA was revealed; no such correlation was observed in groups 2 and 3. No correlation of photosensitivity and BCVA was detected in group 1 (r=0.2). Fixation density in the group of paired eyes was significantly lower than in the control group (p<0.001). CONCLUSION: Microperimetry is an innovative tool for differential diagnosis, monitoring, method selection and evaluation of the effectiveness of treatment of various types of amblyopia.

[Fundus albipunctatus with mutations in the RDH5 gene (clinical case)]. / Belotochechnoe glaznoe dno (fundus albipunctatus) s mutatsiyami v gene RDH5 (klinicheskoe nablyudenie).

The article describes a clinical case of a 14-year old patient with RDH5 mutations (OMIM *601617) in patient with fundus albipunctatus (OMIM #136880) and characteristic biomarkers of this disease with previously described pathogenic variant of nucleotic sequence in exon 3 of the RDH5 gene (NM_002905.3:c.500G>A), causing a missense change (p.Arg167His) in heterozygous state and previously not described pathogenic variant of nucleotic sequence in exon 5 of the RDH5 gene (NM_002905.3:c.838C>T), leading to a missense change (p.Arg280Cys) in heterozygous state with characteristic biomarkers of the disease. Best-corrected visual acuity (BCVA) was 20/20. Nyctalopia was accompanied by reduced b-wave of scotopic (dark-adapted 0.01) ERG and decreased amplitude of a- and b-waves of maximum (dark-adapted 3) ERG. Decreased amplitude of the a- and b-waves of photopic (light-adapted 3) ERG and the amplitude of high-frequency (light-adapted 30 Hz) Flicker ERG shows the involvement of retinal cone system in the process. Fundus autofluorescence imaging of both eyes produced fuzzy and grainy images with slight hyperfluorescence of retinal flecks. Optical coherence tomography showed focal thickening centered in the photoreceptor outer segment corresponding to the multiple discrete albipunctate dots.

[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.

[Choroidal thickness in children with myopia and its changes after surgical strengthening of the sclera]. / Tolshchina khorioidei u detei s miopiei i ee izmeneniya posle khirurgicheskogo ukrepleniya sklery.

PURPOSE: To study the choroidal thickness (CT) in children with myopia and hyperopia and its changes after sclera reinforcement surgeries addressing the progression of myopia. MATERIAL AND METHODS: The study involved 133 patients: 78 children (average age 12.5±0.35 years) with mild hyperopia, low, moderate and high myopia and 55 children with moderate and high myopia who received low invasive scleroplasty (LSP, average age 12.31±0.49 years), or bandaging scleroplasty (BSP, average age 12.59±0.24 years) according to Snyder-Thompson technique and were examined prior to and after the procedure. All patients underwent standard ophthalmologic examination and had choroidal thickness manually measured with EDI-SD-OCT; 55 patients were examined before and 1 week after scleroplasty. RESULTS: A reduction of CT with refraction growth and axial elongation was found in 78 patients. Among the 55 patients, changes in CT were statistically significant: in the operated eyes, CT increased by 42.5±3.17 µm after LSP and by 62.1±1.06 µm after BSP. In fellow eyes, CT showed an increase of 26.1±1.79 µm after LSP and 33.7±0.55 µm after BSP. CONCLUSION: In the early period after sclera strengthening, CT significantly increased both in the operated and in the fellow eye. An increase of CT seems to stimulate the collagen biosynthetic activity of the scleral matrix and the collagen synthesis, and to boost the inhibitory effect that scleroplasty has on the myopia progression.

[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.

[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.

[Thickness of the retinal photoreceptor layers and the choroid, and bioelectrical activity of the macula in retinitis pigmentosa]. / Tolshchina fotoretseptornykh sloev setchatki, khorioidei i bioélektricheskaia aktivnost' makuliarnoi oblasti pri pigmentnom retinite.

PURPOSE: To assess the changes in photoreceptor retinal layers and the choroid in comparison with bioelectrical activity of the macula in patients with retinitis pigmentosa (RP). MATERIAL AND METHODS: The study included 10 patients (20 phakic eyes) with RP. Mean age was 27±18.5 years; mean best corrected visual acuity was 0.38±0.22. In addition to standard ophthalmological examination and fundus photography, each patient underwent an electrophysiological study on an electroretinograph MBN (Russia) recording general electroretinogram (ERG), maximal ERG (cone-rod response), 30 Hz flicker ERG and macular ERG (mERG). Choroidal thickness (CT) measurement and segmentation of the retina with following calculation of the thickness of different retinal layers was performed on SD-OCT RS-3000 Advance 'Nidek', Japan), it included obtainment of the 6-mm-diameter map in accordance with the Early Treatment Diabetic Retinopathy Study (ETDRS). RESULTS: The study revealed a decrease in thickness of the choroid, retina, and the photoreceptor layers: 1) the layer with photoreceptor outer segment (OS) and retinal pigment epithelium (RPE) and 2) the layer with photoreceptor inner segment (IS) and outer nuclear layer. Decreased thickness of these layers is associated with the reduction of bioelectric activity of the macula as seen with mERG. CONCLUSION: Decreased thickness of the retina, choroid and photoreceptor layers in all segments of the macula according to EDTRS standards is associated with reduced bioelectric activity of the macula recorded with mERG.

[Peripheral refraction and retinal contour in congenital and acquired high myopia]. / Perifericheskaia refraktsiia i kontur setchatki pri vrozhdennoi i priobretennoi miopii vysokoi stepeni.

AIM: to perform a comparative study of peripheral refraction and retinal contour in patients with congenital versus acquired high myopia. MATERIAL AND METHODS: A total of 30 patients (60 eyes) with high myopia aged 8 to 18 years (11.2±0.32 years on average) were examined. The patients were divided into 2 groups. Group 1 consisted of 21 patients (42 eyes) with acquired myopia of -6.0 to -10.25 diopters (-7.55±0.17 diopters on average), group 2 - of 9 patients (18 eyes) with congenital myopia of -8.75 to -28.75 diopters (-16.39±1.24 diopters on average). Using the Grand Seiko WR-5100K binocular open-field autoref/keratometer (Japan), relative peripheral refraction was assessed with account to relative peripheral eye length measured by the IOL Master partial coherent interferometer ('Carl Zeiss', Germany) at 15° and 30° nasally and temporally from the foveal center along the horizontal meridian. RESULTS: In acquired myopia, relative peripheral refraction and relative peripheral eye length readings evidenced the formation of peripheral hyperopic defocus in all examined zones. Congenital high myopia cases were notable for myopic defocus at 15° of the nasal retina (N15 zone): -0.67±0.33 diopters against the eye length change of -0.33±0.13 mm. CONCLUSION: The research helped identify retinal contour changes characteristic of congenital myopia and indicative of posterior pole irregularity.

[Peripheral refraction: cause or effect of refraction development?] / Perifericheskaya refraktsiya i refraktogenez: prichina ili sledstvie?

AIM: to study peripheral refraction and the shape of the eyeball in children with different clinical refraction. MATERIAL AND METHODS: Using an original method, peripheral refraction was measured at 10-12 degrees temporally and nasally from the fovea in 56 right eyes with different clinical, or axial, refraction of 20 boys and 36 girls aged 7 to 16 years (11.9±1.17 years on average). The shape of the eyeball was judged of by the ratio of its anterior-posterior axial length (AL) to horizontal diameter (HD). RESULTS: The incidence and value of peripheral myopic defocus in children appeared to decrease with clinical refraction increasing from high hyperopia to high myopia. This was the first time, mixed peripheral refraction was found in children, occurring more frequently in higher myopia. This mixed peripheral defocus, shown to be a transitional stage between relative peripheral myopia and relative hyperopia, indicates non-uniform stretching of posterior pole tissues in the course of refraction development and myopia progression. As ocular refraction increases from high hyperopia to high myopia, the growth of AL outpaces that of HD. CONCLUSION: Obviously, natural peripheral defocus results from changes in size and shape of the eyeball in the course of refraction development.

[Experimental realization of minimally invasive techniques of scleral collagen cross-linking]. / Eksperimental'naya realizatsiya maloinvazivnykh tekhnologii krosslinkinga sklery.

AIM: To realize two minimally invasive techniques of scleral collagen cross-linking (SXL) at the equator and posterior pole of the eye: 1) targeted irradiation of the region with ultraviolet A (UVA) and 2) sub-Tenon injection of Sklerateks. MATERIAL AND METHODS: To perform UVA-SXL, a tool was developed that includes a UV-LED light source (370 nm, 3 mW/cm2) and a polymer-coated silica multimode optical fiber located in one of the two channels of a detachable metal tip. The other channel is used to deliver riboflavin to the scleral surface. The study included 8 Chinchillas' eyes. Intact fellow eyes served as the controls. Scleral echodensity was measured in vivo with Voluson 730 Pro (Kretz) prior to the procedure and then 2 days and 1 month after. After enucleation, the elastic modulus and the degree of scleral cross-linking were established at the same time-points. A placebo-controlled study on the safety and effectiveness of sub-Tenon Sklerateks injections (solution of amino acid salts in the form of succinates) was conducted on 47 Chinchilla rabbits (94 eyes). Sklerateks or placebo (0.1 ml) was injected below the Tenon's capsule of either eye once a week for 1 month (4 injections; 1st series) or 3 months (12 injections; 2nd series). After the end of the course, 22 eyes were studied morphologically. In 72 eyes, scleral samples were obtained in order to evaluate the elastic modulus (Autograph AGS-H tester, SHIMADZU, Japan) and the rate of cross-linking (judging from the denaturation temperature) by differential scanning calorimetry (Phoenix DSC 204 calorimeter, Netzsch, Germany). RESULTS: After UVA irradiation, the scleral echodensity increased from 86.7±5.1 to 98±4.9 dB. The elastic modulus appeared 1.5 times higher than that of the control samples. The denaturation temperature also increased indicating the rate of scleral cross-linking as high as 15-18%. Weekly Sklerateks for 1-3 months has been shown to induce neither clinical, nor morphological signs of local irritative, damaging, or toxic effect. The findings also include: a 1.8 times higher rate of scleral cross-linking, activation of cellular elements, neoformation of connective tissue on the scleral surface, and vascular growth, which together indicate a pronounced metabolic and strengthening effect of Sklerateks on the sclera. CONCLUSION: Experimental results on minimally invasive techniques of SXL allow to recommend them for further clinical investigation as a promising treatment of progressive myopia.

[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.

[Results of corneal and total astigmatism estimation by different methods in myopic patients wearing orthokeratology contact lenses].

Reports have been made that corneal aberrations of all orders, including astigmatism, often significantly increase with the use of night orthokeratology lenses. In this study the dynamic changes of total and corneal astigmatism in myopes using orthokeratology lenses was evaluated by different methods. The study enrolled 38 patients (76 eyes) with low and medium myopia (28 and 48 eyes correspondingly) and initial astigmatism less than 2 diopters. The assessment was made before and in different terms after the patient started to wear orthokeratology lenses. Induced astigmatism (> or =1 diopter) was found in more than 50% of cases. The degree of astigmatism gradually increased from the centre to the periphery within the papillary zone. The maximum values were found within a 4-mm zone ("uptake zone") and minimal - within a 8-mm zone ("equalization zone"). In all patients, despite the presence of induced astigmatism and residual myopia (0.83+/-0.09 diopters in average), distance visual acuity was high enough without an additional correction (0.82+/-0.05 in average). Apparently, in these patients the aberrations (astigmatism in particular) exceed the focal depth.