[Optical aberrations of the eyes with various degrees of myopia]. / Aberratsii opticheskoi sistemy glaza pri miopii razlichnoi stepeni.

Purpose - to comparatively analyze the wavefront aberrations and biometric parameters of the eyes with various degrees of myopia. MATERIAL AND METHODS: The study included 134 eyes of 67 patients with mild, moderate and high myopia aged 7-28 (mean age 19.3±1.5 years). The following biometric parameters were examined: anterior chamber depth (ACD), lens thickness (LT), axial length (AL), as well as corneal and total aberrations. The parameters were studied on the Galilei G6 system (Ziemer Ophthalmic Systems AG, Switzerland) and the OPD-Scan III aberrometer (Nidek, Japan). Spherical aberration (SA) was estimated as the sum of Z4+Z8+Z12. RESULTS: As the refraction increased, the root mean square higher-order aberrations (RMS HOA) also increased significantly: from 0.24±0.02 µm in mild myopia to 0.45±0.03 µm in high myopia, and in eyes with AL of ≥27.0 mm - to 0.57±0.02 µm (p=0.01). An increase in vertical tilt, vertical coma and vertical trefoil were also observed. Total SA was positive and increased in eyes with moderate myopia compared to those with low myopia (from 0.02±0.01 µm to 0.06±0.02 µm, p=0.02), which coincided with changes in the internal optics of the eye: an increase in ACD and a decrease in LT. At the same time, no differences in corneal aberrations were observed among patients with low and moderate myopia. A significant decrease of SA occurred in high myopia (from 0.06 µm in low myopia to 0.015±0.02 µm in high myopia). The average value of SA was 0.005±0.01 µm in eyes with AL of ≥27.0 mm and appeared to be negative in 40% of cases. The average value of corneal SA was negative (-0.002±0.01µm) in eyes with AL of ≥27.0 mm. This group had predominantly patients with congenital myopia. CONCLUSION: An increase of total positive SA in patients with moderate myopia compared to those with low myopia is associated with changes in the internal optics of the eye (ACD, LT). Significant increase of higher-order aberrations and decrease of SA with the transition to negative values was observed in patients with high axial 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.

[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.

[Correlation between biomechanical properties of the corneoscleral tunic and stereometric parameters of the optic nerve head in congenital and acquired myopia].

The correlation between biomechanical properties of the corneoscleral tunic and stereometric parameters of the optic nerve head in children and adolescents with congenital and acquired myopia has been studied comparatively. The results showed that in children with high myopia, congenital or acquired, the corneoscleral parameters (scleral echodensity at the equator and the posterior pole, corneoscleral hysteresis, cornea resistance factor, and ocular rigidity coefficient) are lower than those in emmetropes. Moreover, the corneoscleral biomechanical characteristics affect the optic nerve head parameters. This fact has to be taken into account when examining adults with high myopia for the purpose of early diagnostics of glaucoma.

[Acoustic density of sclera as a prognostic factor of peripheral vitreochorioretinal degenerations in myopia: results of 10-years follow-up].

Prognostic value of acoustic density of sclera (ADS) is studied in development of peripheral vitreochorioretinal degenerations (PVCRD) in myopia. Children aged 8-10 years old with noncomplicated high and moderate myopia were divided into two groups after ADS measurement: 1 with ADS < or = 39dB - unfavorable prognosis, 2 with ADS >39dB - favorable prognosis. Follow-up during 10 years with examinations twice a year confirmed prognosis accuracy: in the 1st group PVCRD developed 2.5 times as often as in the 2nd group (64.6 and 25.6% respectively).

[Morphometric and functional features of macula in patients with high congenital myopia].

Combined use of OCT and ERG allowed us to study correlation of functional changes and morphological retinal features in patients with congenital myopia with or without myopic maculopathy. The study revealed the following features of retinal contour in macula region in congenital myopia compared to emmetropia: increase of neuroepithelial thickness in fovea centre, trend to decrease of its thickness in perifoveolar zone, significant (1,7-fold) reduction of neuroepithelial thickness difference between central and pericentral zones and subsequently change of retinal profile. Revealed data should be considered in retinal thickness evaluation of adults with high myopia and in assessment of normal postnatal macula development in children with high myopia. Combination of ophthalmoscopy, OCT and m-ERG may help in early diagnosis and monitoring of progressing macula changes.

[Retinal bioelectrical activity in children with congenital myopia].

Congenital myopia is a particular form of short sight that forms in the intrauterine development of a fetus and that is generally characterized by high myopia, a longer anteroposterior axis (APA) of the eye, and its fundal changes. The authors have studied the functional state of the central and peripheral retinal segments in children with congenital myopia by electric retinography (ERG). They examined 23 patients (46 eyes) aged 6 to 16 years, who had moderate and high congenital myopia, the diagnosis in whom had been established in their early life, with various ophthalmoscopic manifestations: without macular changes, with the hyperpigmented macula, an undifferentiated macular region, and acquired chorioretinal dystrophy. Visometry, refractometry, ophthalmoscopy, ultrasound biometry (APA measurement), and mixed, local, and multifocal ERG were performed. Four patients were diagnosed as having congenital persistent nocturnal blindness of the Schubert-Bornstein type. Varying bioelectrical activity changes in the retinal macular region were revealed in congenital myopia both in the absence of ophthalmoscopic changes and with the changes in the fundus of the eye as macular hyperpigmentation, undifferentiated macular region, and central chorioretinal dystrophy. There was a moderate and high inverse correlation between the parameters of bioelectrical activity (the amplitude of b wave of the maximum ERG, that of b wave of local ERG and the retinal density of a P1 component in all rings) on the one hand, and the spherical equivalent of refraction and the length of ADA, on the other.

[Reinforcement of the sclera with new types of synthetic materials in progressive myopia]. / Ukreplenie sklery novymi vidami sinteticheskikh materialov pri progressiruiushchei blizorukosti.

The possibility of using a new synthetic material mersilene for scleroplastic operations has been evaluated in experiments and clinical trials were carried out in patients with progressive myopia subjected to sclera fortification. Morphological studies showed the formation of a connective tissue capsule round mersilene; new collagen fibers grow through its cellular structures, thus fortifying the strength of the sclera-graft complex. Clinical results indicate that sclera fortification by a mersilene graft arrested the progress of myopia in almost all (98%) patients by the end of the first year postoperation; by the end of the second year, myopic refraction stabilized in 92% patients. Hence, mersilene transplants are recommended for scleroplasty in progressive myopia.

[The morphological characteristics of the take of synthetic transplants following experimental scleroplasty]. / Morfologicheskie osobennosti prizhivleniia sinteticheskikh transplantatov posle skleroplastiki v éksperimente.

The morphology of taking in of synthetic transplants after scleroplasty is studied in 24 eyes of chinchilla rabbits. Polytetrafluorethylene-based materials (composite filtration fluoroplast membrane--Teflon) and polyester jersey with reticular structure (scleracod) were used for transplantation. Study of two materials showed common processes and differences in the grafts taking in. Implants made of both materials are characterized by good biocompatibility, which prompts further investigation of their probable use in sclera-fortifying treatment of progressive myopia.