CLINICAL AND FUNCTIONAL RESULTS OF CATARACT SURGERY EMPLOYING A COMBINATION OF ND-YAG (1.44ΜM) AND HE-NE (0.63ΜM) LASER RADIATION FOR CRYSTALLINE LENS FRAGMENTATION

Purpose. To investigate and compare the results of clinical application of microinvasive laser cataract extraction (mLCE) based on combined impact of endodissector (Nd-YAG laser 1.44μm) and bio-stimulator (low-power He-Ne laser 0.63μm) with a basic laser cataract extraction technique (LCE) and microinvasive ultrasound phacoemulsification (mPE).Material and methods. Senile cataract extraction with implantation of elastic IOLs into capsular bag was performed in 3 groups of patients: mLCE was performed in 148 eyes, LCE – in 176 eyes and mPE – in 204 eyes.Results. As a whole, surgery and postoperative period coursed with no complications and with minimal reactivity. When compared mLCE with LCE there were reduced energy power, reduced volume of irrigation, less induced astigmatism, better corneal thickness and endothelial cell count loss. When compared mLCE with mPE, the number of eyes with corneal edema was 2 times less, along with reduced transient hypertension and corneal endothelial cell count loss.Conclusion. The developed mLCE technology using two kinds of laser radiations, has several significant clinical advantages providing better safety and efficacy of senile cataract surgical treatment

RELIABILITY OF INDICATORS OF DEVICES MEASURING GEOMETRIC PARAMETERS OF CORNEA

Purpose. To determine an optically significant measurement zone and to assess an accuracy of geometrical corneal parameters measurements using different keratometric devices based on different measurement techniques.Material and methods. The clinical trial included 70 patients (90 eyes), where a study of corneal geometrical parameters was performed by the method of three measurements obtained during different examinations. According to the value of measurement deviation the accuracy of the tested devices was assessed: the Huvitz autorefractor-keratometer (AK) (South Korea), the Zeiss manual keratometry built-in slit lamp (MK) (Germany), the Shin-Nippon topographer CT-1000 (CT) (Japan), the Pentacam HR Oculus Scheimpflug camera (Germany), the Zeiss IOL-Master optical coherence interferometer (IM) (Germany). Additionally, measurements of each device in a 3mm zone of cornea were compared to the data obtained by the manual keratometry and in the Shin-Nippon topographer CT-1000 and the Pentacam HR Oculus Scheimpflug camera the 5mm and 7mm zones data were used as well.Results. The least variation among measurements was registered in the MK (0.17±0.15), the IM (0.21±0.22) and the Pentacam in the 3mm zone (0.22±0.16); the largest variation was registered in the AK (0.45±0.28) (p≤0.05). The least differences from the MK data were registered in the IM (0.16±0.26) and the Pentacam computer topographer in the 3mm (0.11±0.13), 5mm (0.10±0.06), and 7mm (0.11±0.06) zones (p>0.05). The largest differences were registered in the CT in the 5mm zone (0.63±0.29).Conclusion. The most reliable results among the tested devices are obtained by the manual keratometry, the Pentacam and the IOL-Master. The 3mm zone is the most optically significant because it has the least quantity of divergences between examinations

CORNEAL ENDOTHELIUM CELLS RESPONSE AFTER LASER AND ULTRASOUND PHACOFRAGMENTATION. ELECTRON MICROSCOPY IN EXPERIMENT. Report 3

Purpose. To evaluate a laser energy safety level by comparison of corneal endothelium cells response after various methods using energy of ultrasound and laser phacofragmentation.Material and methods. Ultrasound phacoemulsification (Millennium) was performed in 3 right cadaver human eyes (males, 68-72 years) 6 hrs post mortem. Laser phacofragmentation was performed in 3 left eyes of the same individuals using the Russian device “Rakot” (Nd:YAG 1.44μm). Electron transmission microscopy (ETM) of pigment epithelium in macular area of retina was carried out.Results. Electron microscopy of corneal endothelium monolayer after laser phacofragmentation found NO significant abnormalities. After ultrasound phacoemulsification we detected areas with defects in endothelium monolayer sized 3-7 cells with round shape and smoothened cushion –like edges incorporating endothelial cells fragments with mostly cell nuclei parts. Posterior surface of the descemet’s membrane was a bottom of the existing hollow defects.Conclusions. Compared to ultrasound energy the laser energy in phacofragmentation inflicts NO adverse effects on highly sensitive corneal endothelium

INTRAOCULAR CORRECTION OF HIGH-DEGREE AMETROPIA USING INDIVIDUAL MULTIFOCAL IOL

Purpose. To show a possibility of intraocular correction of high ametropia with astigmatism using toric multifocal LentisMPlus IOLs. Material and methods. We observed two patients: the first female patient, 39 years old with a diagnosis of OU: high myopia, compound myopic astigmatism, initial complicated cataract, moderate amblyopia, peripheral chorioretinal degeneration (PCRD). On admission the distance visual acuity was vis OD=0.01 sph (-) 15.5 D cyl (-) 2.5 D ax 0°=0.6; vis OS=0.01 sph (-) 18.0 D cyl (-) 2.5 D ax 0°=0.5. The second patient was a 35-year woman with a diagnosis of OU: high hyperopia, compound hyperopic astigmatism, moderate amblyopia. Distance visual acuity on admission was OD=0.03 sph (+) 8.0 D cyl (+) 1.5 D ax 95°=0.5; OS=0.03 sph (+) 8.0 D cyl (+) 0.75 D ax 75°=0.6. Individual multifocal toric IOLs were implanted in both patents after the removal of the lens phacoemulsification. All standard ophthalmic examinations were used as well as the ultrasound biomicroscopy (UBM). Results. In the follow-up: 6 months after the surgery in the first patient the uncorrected visual acuity (UCVA) was far vis OD=0.6, vis OS=0.5, near vis OD=0.4, vis OS=0.5, middle distance vis OD=0.4, vis OS=0.4. The second patient 3 months after surgery had the UCVA far vis OD=0.5, vis OS=0.6, near vis OD=0.4, vis OS=0.5, middle distance vis OD=0.2, vis OS=0.3. The maximum possible distance visual acuity was achieved in both cases. Conclusion. The LentisMplus IOL with a toric component, made custom taking into account individual features of eyes allow to achieve clinical and functional results declared by the manufacturer of these lenses for the standard diopter range

RETINAL PIGMENT EPITHELIUM CONDITION AFTER LASER AND ULTRASOUND PHACOFRAGMENTATION. ELECTRON MICROSCOPY IN EXPERIMENT. REPORT 1

Purpose. To perform a comparative evaluation of a macular retinal pigment epithelium condition after laser and ultrasound phacofragmentations in experiment.Material and method. Electron microscopy of macular retinal pigment epithelium was conducted in 3 cadaver eyes after the laser (Nd:YAG 1.44µm) phacofragmentation using the Russian device «RAKOT» and in 3 fellow eyes – after the ultrasound phacoemulsification using Millenium phacomachine.Results. After the laser phacofragmentation the ultra-structure of pigment retinal epithelium in macular area corresponded to the norm. After the ultrasound phacoemulsification some disturbances were noted in the ultra-structural organization of retinal pigment epithelium cells manifested in a rarefaction of the electron optical density of the cell cytoplasm, in an increase of vacuoles.Conclusion. Laser energy is safer for the posterior segment of the eye than ultrasound energy used in the cataract surgery