Thickness of the choroid, ciliary body and retina according to optical coherence tomography in patients after Femto LASIK

Background. In the available literature, there are isolated publications devoted to the topic of the possible effect of laser correction by the Femto LASIK method on the myopic eye choroid. In this connection, in our opinion, the relevance of continuing research in this direction remains.The aim of this study was to examine the volume of the retina in the macular zone, the thickness of the choroid and the ciliary body using optical coherence tomography on myopic eyes after femtosecond-assisted laser in situ keratomileusis in the short term.Material and methods. 30 patients (30 right eyes) aged 20 to 35 years, suffering from mild and moderate myopia, but without pathological changes in the retina according to OCT, made up the study group. All patients underwent myopia correction using the Femto LASIK method. Before the operation, after 4 hours and the next day, they underwent the examination of the retinal volume in the macular zone, the choroidal and the ciliary body thickness using OCTResults. The analysis of the obtained results of the studied parameters showed that the ciliary body thickness and the retinal volume in the macular zone did not undergo statistically signifi cant changes and remained within the preoperative values (p > 0.05). We observed a tendency to an increase in the thickness of the choroid 4 hours after the operation, but the carried out statistical analysis did not confi rm the reliability of its changes (p > 0.05). On the next day, the choroidal thickness indices practically recovered to the preoperative level (p > 0.05).Conclusion. A study of the retinal volume in the macular zone, the thickness of the choroid and ciliary body using OCT in myopic eyes in the short term after Femto LASIK showed the absence of statistically signifi cant changes in the studied parameters, which indirectly indicates the safety of this method of laser correction for the posterior segment of the eye

PECULIARITIES OF CORNEAL EPITHELIAL LAYER STATE AFTER THE RELEX® SMILE ACCORDING TO OPTICAL COHERENCE TOMOGRAPHY DATA

Purpose. Prospective study of corneal epithelial layer thickness (CET) changes after the ReLEx® SMILE in case of a low and moderate myopia correction.Material and methods. The «SMILE» study group included 46 patients (46 eyes) with the mean age 26.02±5.18, the mean spherical equivalent was 4.02±0.22D, the follow-up period was 6 months and less. All patients were examined using the optical coherence tomography (OCT) with the xR AVANTI (Optovue, Inc) pre-operatively and 1 day, 2 weeks, 1, 3, 6 months post-operatively, the ametropia laser correction was performed by the ReLEx® SMILE method using the VisuMax® (500 kHz, Carl Zeiss Meditec AG).Results. After 6 months in 43 patients the uncorrected visual acuity (UCVA) was 0.9-1.0 (93.5%), the refraction within ±0.5D of the planned one was achieved in 89.1% (41 eyes), ±1.0D – in 100% of cases. Epithelial hyperactivity was noted during the first 3 months (Р<0.001). The difference in CET compared with preoperative data in the central corneal area was 5.98±0,38μm (11.09%), the minimum growth was detected in the nasal sector (5-6mm) – 4.19±0.27μm (7.92%), the maximum – in the temporal area (2-5mm sector) – 7.17±0.45μm (13.61%). Epithelial corneal remodeling after the ReLEx® SMILE retained the preoperative statistically significant difference in the CET in the upper and lower segments (Р<0.001) and conversely changed into the opposite pattern in the temporal and nasal segments (Р<0.02).Conclusion. The obtained results show a statistically significant growth of corneal epithelial layer thickness in the correction of low and moderate myopia by the ReLEx® SMILE method predominantly in the early postoperative period

A NEW APPROACH TO THE PREVENTION OF INTRA-OPERATIVE COMPLICATIONS IN THE CORRECTION OF COMPOUND MYOPIC ASTIGMATISM USING THE RELEXS®MILE METHOD

Purpose. To study the efficiency of a preoperative inhalation session of oxygen-xenon mixture in the mode of analgosedation for stressunstable patients at the preoperative preparation stage for the ReLEx®SMILE method.Material and methods. The study group consisted of 11 patients (mean age 22.76±1.43 years) with a high degree of anxiety (>46 points), according to the Spielberger State-Trait Anxiety Inventory (STAI). The laser correction by the ReLex® SMILE technology was planned for them (average spherical equivalent (SE) 3.38±0.39D) using the VisuMax™ 500 kHz device (Carl Zeiss Meditec AG). As a preoperative preparation, they underwent the inhalation of an oxygen-xenon mixture in the analgosedation mode. The sessions were performed using the anesthesia XENA-01 device, operating on a closed loop, thereby the xenon exposure was carried out in sub-narcotic concentrations – 35-40% (up to 1/3 МАC).Results. During the analgosedation session with the oxygen-xenon mixture before the ReLEx® SMILE, the hemodynamic and ventilation parameters in the patients of the study group remained stable. By the 20th minute the patients calmed down, fell asleep, heart rate decreased up to 55.4±5.3 per minute. The 40% xenon exposition was 20 minutes. The xenon consumption was 4.5±0.7 liters per session.During the ReLex® SMILE, the patients, remaining fully conscious, behaved adequately and calmly. The stage of interface applanation to the cornea, its centering, femto-dissection occurred without complications in all patients. The planned refractive result was achieved in 100% of cases (the mean SE was 0.25±0.1D). The next day after the procedure, the UCVA in all patients was 0.9-1.0.Conclusion. The analgosedation session with an oxygen-xenon mixture provides an adequate nociceptive and anti-stress protection, guarantees safe laser ophthalmic interventions in emotionally labile patients. The obtained results of the study allow to consider this premedication method before the femto-laser correction of ReLEx® SMILE as a new approach to the prevention of such an intraoperative complication as the vacuum loss

The Long-Term Results of ReLEX® SMILE Depending on the Degree of the Corrected Myopia

The purpose: prospective study of the long-term refractive and visual results of ReLEx® SMILE, depending on the degree of corrected myopia.Material and methods. The three study groups included 71 patients; the mean age was 26.48 ± 5.5 years. Group I consisted of 20 patients (39 eyes) mean SE –2.62 ± 0.87 D, group II — 26 patients (51 eyes), mean SE 4.68 ± 0.74 D, Group III — 25 patients (47 eyes), mean SE 6.88 ± 0.72 D. All patients underwent femtolaser correction of myopia using the ReLEx® SMILE method with the VisuMax™ laser system (Carl Zeiss Meditec AG).Results. Uncorrected visual acuity of 09 — 1.0 was noted in 34 eyes (87.2 %) in group I, in II — in 43 eyes (84.3 %), in 37 eyes (78.7 %) in group III. The efficiency coefficient was 1.0 in groups I — II and 0.89 in group III. There was no decrease in corrected visual acuity (CVA) during the correction of mild and moderate myopia, in group III it was recorded by 0.1 in two cases (4 %), by 0.2 in one case (2 %), the safety factor in I — II groups 1.0, in III 0,89. Two years after ReLEx® SMILE, refraction of ± 0.5 D from planned in the study groups was achieved, respectively, in 94.9, 88.2, 76.6 % of cases, ± 1.0 D in 100 % of cases in I, II groups, in 97 % of cases in III group. The predictability coefficient was 0.95 in group I, 0.88 in group II, and 0.77 in group III. Refractive regression compared with the results 1 month postoperatively was 0.08 D in group I, 0.1 D in group II, and 0.16 D in group III. Analysis of the long-term results of ReLEx® SMILE allows us to conclude: the method is safe and effective, provides high predictability of refractive results in correcting various degrees of myopia. Further study of the long-term results of the operation, the creation and use of nomograms, taking into account the individual characteristics of the cornea, will improve the predictability and stability of refractive results in the correction of high myopia