Femtosecond sub-Bowmen keratomileusis at the peak of the action of Botulinum toxin A, introduced into extraocular muscles in a patient with nystagmus: A clinical case

A clinical case of excimer laser correction performed by sub-Bowman femtosecond keratomileusis at the peak of botulinum toxin A effect in a patient with high congenital anisometropic myopia and horizontal nystagmus is presented. Keratorefractive surgery improved functional visual performance and the parameters of nystagmus

A symmetric hypocorrection of myopia by FemtoLASIK in patients with presbyopia

Purpose: to evaluate the results of symmetric binocular hypocorrection of myopia with FemtoLasik surgery in patients with presbyopia of various age groups.Material and methods. 33 patients (66 eyes) with myopic refraction, aged 36 to 50, were operated by FemtoLasik. The intended Femto Flap thickness was 100 μm. The patients were divided into three groups depending on age; group 1 included 16 patients (32 eyes) aged 39–44, group 2 had 12 patients (24 eyes) aged 45–50, and group 3 (controls) was composed of 5 patients (10 eyes) of pre-presbyopic age (36–38 years).Results. The symmetric binocular hypocorrection proved efficient in 35 % of cases in the group 1 and 50 % of cases in group 2. In the control group the intended and obtained values coincided in all 100 % of cases.Conclusion. A possible cause of the discrepancy between the intended and the obtained hypocorrection effect may be a reduced corneal hydration of patients older than 39 years

Can the progression of myopia be restrained by monolateral excimer laser correction?

The purpose of this study was a comparative assessment of the refraction and the axial length (AL)  changes occurring in the operated and unoperated  eyes of patients with anisometropic  myopia who underwent  unilateral  excimer laser correction.Material  and methods. We observed 13 patients (8 women and 5 men) aged 21 to 53 years (34.2 ± 8.6) with anisometropic myopia (averagely, with spherical equivalent of refraction -3.87 ± 1.77 D in one eye and 0.71 ± 0.71 D in the other), who underwent unilateral LASIK. The observation period was 3-5 years (averagely 3.5 ± 1.1 years). The observation included autorefractometry on a Nidek ARK-530A apparatus, ultrasound biometry on a Nidek US-1800 Echosсan (Japan), and pachymetry on a GALILEI G6 (Ziemer, Switzerland).Results. No significant changes in refraction or axial length were observed either in operated or fellow eyes. Changes in the axial length were controversial: 7 operated and 7 fellow eyes showed an increasing tendency while another 6 operated and 6 fellow eyes showed a decreasing tendency (p > 0.05).Conclusion. The data obtained fail to support the assumption that excimer laser reshaping of the cornea produces an inhibitory effect on the development of myopia

Hybrid contact lenses for the correction of primary and induced ametropias

The review presents the data on the use of hybrid contact lenses (HCL), a modern method of contact correction of ametropias of diverse origins. A HCL has a central rigid optical zone made of highly gas-permeable material and a flexible peripheral part made of hydrophilic material. These lenses combine the optical effect of gas-permeable corneal lens with the comfort and stable fitting of soft contact lenses. Compared with the corneal (RGP) lenses, HCLs are more comfortable, often are better centrated and more stably fit on the eye. HCLs are successfully used in various refractive disorders: ametropias (with regular cornea), irregular astigmatism, presbyopia, including that combined with astigmatism. This type of lens is a good option of contact correction for patients who have high requirements to the quality of vision

A comparative analysis of clinical, functional and morphological results of femtosecond, trans-epithelial and standard corneal collagen cross-linking

Purpose: to compare clinical, functional and morphological results of treatment of progressing keratoconus by femtosecond, trans-epithelial and standard corneal collagen crosslinking. Material and methods. 114 patients aged 18-35 (148 eyes) with progressing keratoconus of stages I-III and iatrogenic keratectasia were divided into three groups. Group 1 (39 patients, 47 eyes) received femtosecond corneal collagen crosslinking; group 2 (33 patients, 45 eyes) underwent transepithelial crosslinking and group3 underwent crosslinking performed with standard technique. Results. The analysis of data of confocal microscopy performed 1 year after femtosecond and standard corneal collagen crosslinking revealed the effect of cross linkage in the anterior and middle corneal stroma, an increased density of the extracellular matrix, regeneration of subepithelial and stromal nervous fibers, and keratocyte repopulation. 1 year after trans epithelial crosslinking, keratocyte population was restored. Slight folding in the anterior stroma was observed due to the cross linkage effect. Conclusion. The preserved epithelial layer of the cornea reduces the risk of infectious complications on the eroded surface of the cornea, diminishes visual discomfort and sensation of pain in patients in the early postoperative period, and shortens the rehabilitation period. After trans-epithelial corneal collagen crosslinking, no pronounced effect of cross linkage in the stroma was observed. The available weak positive result justifies the recommendation to use this technique in children, patients with thin cornea, those likely to develop complications during reepithelization, and as a preventive measure in cases of slow progression rate // Russian ophthalmological journal. 2017; 10 (2): 47-53. (in Russian). doi: 10.21516/2072-0076-2017-10-2-47-53

Simultaneous topography-guided photorefractive keratectomy with accelerated collagen cross-linking in the treatment of stage I keratoconus

Purpose: to evaluate the efficiency of simultaneous topography-guided photorefractive keratectomy (PRK) with accelerated collagen cross-linking in the treatment of stage I keratoconus.Material and methods. 38 patients (49 eyes) aged 18 to 44 with stage I keratoconus were treated with simultaneous topography-guided PRK combined with accelerated corneal collagen crosslinking. Along with standard ophthalmological testing, patients underwent aberrometry, confocal microscopy, optical coherence tomography of the cornea, imaging of the anterior eye section on a Scheimpflug analyzer, and examination of the biomechanical properties of the cornea. The follow-up period was 2 years.Results. Two years after surgery, uncorrected visual acuity which originally was 0.23 ± 0.03 showed a statistically significant increase and reached 0.72 ± 0.02; best corrected visual acuity improved from 0.44 ± 0.03 to 0.89 ± 0.02; the refractive power of the cornea fell from 45.03 ± 0.28 to 42.55 ± 0.31 D; the spherical component of refraction reduced from -2.00 ± 0.19 to -0.73 ± 0.09 D; the cylinder component reduced from 2.46 ± 0.14 to 0.79 ± 0.07 mm, the thinnest point of the cornea reduced from 486.30 ± 4.78 to 406.80 ± 6.51 μm. The highest order aberrations showed the following results: Coma index reduced from 0.27 ± 0.12 to 0.08 ± 0.07, Tilt reduced from 0.53 ± 0.11 to 0.10 ± 0,09, and Trefoil reduced from 0.13 ± 0.04 to 0.05 ± 0.02.Conclusion. The analysis of clinical and functional results, biomechanical properties and structures of the cornea confirmed the efficacy and safety of the combined treatment of patients with stage I keratoconus

Change in the Ophthalmobiometric Parameters in Myopia and Hyperopia under the Influence of Cycloplegia

Purpose: comparison of some ophthalmobiometric parameters in natural and cycloplegic conditions in myopia and hypermetropia.Material and methods: eyes biometric parameters were examined (the depth of the anterior chamber, the lens thickness and AL)before and after cycloplegia (1% Cyclopentolate hydrochloride — 2 times) in 244 eyes with myopic and hyperopic refraction in 122patients aged 5–32 years. Biometric parameters were examined on the Galilei G6 optical system analyzer (Ziemer Ophthalmic SystemsAG 6.0.6). The thickness of the choroid was measured with a spectral optical coherent tomograph (SD-OCT wavelength 800 nm) of Nidek RS-3000 Retina Scan Advance in 20 eyes of 10 patients aged 11 ± 1.3 years from the examined group before and 40 minutes after double injection of 1% Cyclopentolate hydrochloride. Results: the depth of anterior chamber and the axial, both in the narrow pupil and under the cycloplegia, are significantly higher in the myopic eyes than in the hyperopic eyes (p < 0.05 for ACD and p < 0.01 for AL), and the lens thickness is practically does not differ. In absolute terms, the position of irido-lens diaphragm, i.e. distance from the posterior surface of the cornea to the center of the lens in myopia group was significantly higher than with hyperopia respectively, of 5.62 ± 0.02 mm of 5.29 ± 0.01 mm (p < 0.01). However, the coefficient Lowе ((ACD + 1/2LT)/AL) in myopia was significantly lower (of 0.219 ± 0.001 and 0,238 ± 0,001, respectively) is due to the greater of the AL. After cycloplegia, in both myopic and hyperopic eyes, DAC increases: in myopia, on average, 0.12 mm, with hyperopia — by 0.14 mm, and accordingly the thickness of the lens decreases. The coefficient Lowe in both cases is increased by 0,04 mm. Interesting changes were observed in the length of AL: under conditions of cycloplegia, it decreased by 0.03 mm (30 microns) in eyes with myopia (p > 0.05) and by 40 microns (0.04 mm) with hyperopia (p < 0.01). Conclusion: In cyclopegic condidions, as compared to the existing accommodation, increasing the depth of the anterior chamber decreased the thickness of the lens center of the lens somewhat extended posteriorly and decreases the axial length. The revealed changes in the AL can be associated with a change in the position of the pigment epithelium layer due to changes in the thickness of the choroid under different accommodation conditions. The significant changes in the thickness of the choroid the influence of cycloplegia was not proved in this study

Difference in profile of peripheral defocus after orthokeratology and eximer laser correction of myopia

A variety of factors that change the topography of the cornea may also induce changes in peripheral refraction. Purpose. The paper is aimed at assessing the peripheral refraction and retinal contour of myopic eyes after FS-LASIK and orthokeratological (Ortho-k) correction. Materials and methods. We examined a total of 30 patients (60 eyes) aging from 28.86 ±2.83 years which included 12 patients (24 eyes) with myopia of -5.11 ± 0.5 D and with an axial length (AL) of 25.04 ±0.33 mm before and 1 month after FS-LASIK surgery, and also included 18 patients (36 eyes) with myopia of -5.4 ± 0.24 D and AL of 25.78 ± 0.2 mm who wore ESA-DL Ortho-k lenses. The peripheral refraction of all the patients was measured using the Grand Seiko Open-field binocular autoref/keratometer and the peripheral eye length was measured using the IOL Master 500 (Carl Zeiss) at 15° and 30º nasally (N) and temporally (T), respectively, from the center of fovea. Results. The peripheral eye length measured before and after FS-LASIK as well as after Ortho-k correction was less in all peripheral zones than in the center, which corresponds to characteristics observed in hyperopic peripheral defocus. Refraction measured after FS-LASIK showed the formation of myopic defocus with a maximum at 30° from the following results: -2.49 D at T15°, -2.5 D at N15°, -6.73 D at T30°, and -7.8 D at N30°. The maximal myopic defocus after Ortho-k correction was detected in the middle periphery from these following results: -4.89 D at T15°, -5.51 D at N15°, -2.92 D at T30° and -2.4 D at N30°. Conclusions. Both procedures induced a significant peripheral myopic defocus. In the first case, the maximum values of defocus were detected in the peripheral zone (30° from the center of the fovea); in the second case, the maximal effect on the middle periphery was identified 15° from the center. Such patterns of peripheral refraction fully coincided with the specific changes in corneal topography after the two procedures. The retinal contour within 30° from the center retained the relative hyperopic defocus characteristic of intact myopic eyes // Russian Ophthalmological Journal, 2017; 1: 31-5. doi: 10.21516/2072-0076-2017-10-1-31-35

Comparative Analysis of the Wave Front Aberrations and Ophthalmoergonomic Parameters after Excimer Laser and Orthokeratological Correction of Myopia in Patients over 35 Years

Purpose. Comparative analysis of the wavefront aberrations and ophthalmoergonomic parameters after excimer laser and orthokeratological correction of myopia in patients aged over 35 years.Patients and methods. The study included 21 patients: 12 (24 eyes) after excimer laser correction of myopia (group 1) and 9 (18 eyes) after orthokeratology (group 2). The average age of patients after excimer laser surgery was 38.5 years, after orthokeratological correction 46.1 years. Special studies included ophthalmoergonomical tests: far and near distance visual acuity, capacity of the visual analyzer, visual productivity, reading velocity, mesopic vision, relative accommodation reserves, objective accommodative response, pseudo-accommodation volume. Wavefront aberrations were conducted on the OPD-scan 3.Results. The spherical equivalent of residual refraction was –0.625 ± 0.08D in the excimer group, and –1.58 ± 0.24D in orthokeratological group. Despite the difference in refraction, values of distance binocular and monocular visual acuity were the same in both groups: in group 1 monocular visual acuity was 0.74 ± 0.03, binocular 0.85 ± 0.03; in group 2 — 0.71 ± 0.06 and 0.89 ± 0.05 respectively. The parameters of both monocular and binocular accommodative response measured on Grand Seiko were 50 % higher in the excimer group compared to those in the orthokeratological group. Relative accommodation reserves appeared to be two times more in the excimer group. The volume of pseudo-accommodation was 2.375 ± 0.12D in group 1, which appeared to be 20 % more than in the group 2 (p = 0.0414). The level of wavefront aberrations was significantly higher in orthokeratological group with the exception of vertical aberrations and, especially horizontal coma, which were significantly higher after excimer laser surgery. Generally, the dynamics of aberrations in both groups correlates with changes of the corneal topography.Conclusion. Excimer laser surgery with hypocorrection is more recommended for patients aged 35–40, and orthokeratological correction for patients over 45 years old