[Pseudo-accommodative intraocular lenses]. / Intraokulyarnye linzy s funktsiei psevdoakkomodatsii.

This article reviews pseudo-accommodative intraocular lenses (IOLs), providing an analysis of the terminology used in this field of ophthalmology and describing the design of modern IOLs, the technological features used to achieve pseudo-accommodation that meets the needs of patients, particularly the new extended depth of focus (EDOF) IOL technology. The article presents the main types of extended depth of focus IOLs, their description, advantages and disadvantages, as well as comparison with multifocal and monofocal IOLs based on clinical studies conducted in different countries.

[Comparative study of corneal densitometry values after posterior lamellar keratoplasty]. / Sravnitel'nyi analiz opticheskoi densitometrii rogovitsy u patsientov posle zadnei posloinoi keratoplastiki.

Studying clinical and functional outcomes of femtosecond laser-assisted posterior lamellar keratoplasty is an actual problem in endothelial keratoplasty. PURPOSE: To compare the values of corneal densitometry (CD) as measured by the Scheimpflug camera (Pentacam) following femtosecond laser-assisted Descemet stripping endothelial keratoplasty (DSEK) vs microkeratome-assisted Descemet Stripping Automated Endothelial Keratoplasty (DSAEK). MATERIAL AND METHODS: The prospective single center randomized study included 37 eyes of 37 patients with Fuchs endothelial dystrophy and cataract. 20 patients underwent cataract phacoemulsification combined with Femto-DSEK; 17 patients of the control group underwent cataract phacoemulsification combined with DSAEK. Outcome measurements included optical coherence tomography of the anterior segment of the eye, endothelial microscopy and densitometry. Optical density of the cornea and its various layers: anterior layer (AL), central layer (CL), posterior layer (PL) and interface zone was assessed in the 0-2 and 2-6 mm zones. The follow-up period lasted 1 year. RESULTS: Comparative analysis did not reveal statistically significant differences in AL, CL, and CCT values between the groups (p>0.05). In the Femto-DSEK group, densitometry indices of the posterior layers of the cornea and the interface zone were significantly higher than in the DSAEK group (p<0.05). Postoperative uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) differed significantly throughout all follow-up period with DSAEK group having better results (p<0.05). Endothelial cell density (ECD) at 12 months was higher in the Femto-DSEK group compared with the DSAEK group (65.7±7.7% and 58.5±8.1%, p=0.02, respectively). CONCLUSION: After one year, corneal density values (AL, CL, PL) and CCT were comparable between the groups. UCVA, BSCVA and ECD were significantly better after DSAEK.

[Ultraviolet crosslinking in the treatment of keratoconus in patients with thin corneas]. / Ul'trafioletovyi krosslinking v lechenii keratokonusa pri sushchestvennom umen'shenii tolshchiny rogovitsy.

Corneal collagen cross-linking (CXL) is a procedure that aims to halt the progression of corneal ectasia in keratoconic eyes. It is achieved by inducing cross-links in the corneal stroma and extracellular matrix by exposing it to ultraviolet-A (370 nm) irradiation while it is filled with photosensitizer (riboflavin). According to the conventional protocol, the recommended de-epithelialized corneal thickness should be higher than 400 µm in order to avoid radiation damage to the corneal endothelium. However, in progressive keratoconus, corneal thickness is often close to or lower than this threshold of 400 µm, which limits the application of cross-linking for these patients. The present article reviews the different protocols of cross-linking for thin corneas, their advantages and disadvantages. At present, clinical research on modified cross-linking protocols is still limited due to the methodology and a low number of patients involved. Thus, comparative randomized controlled studies with long-term follow-up are necessary to confirm the safety and effectiveness of several CXL protocols and identify the most efficient one.

[Transplantation of endothelium and Descemet's membrane]. / Transplantatsiia éndoteliia i destsemetovoi membrany.

Nowadays, endothelial keratoplasty has become an alternative to penetrating keratoplasty (PKP) in the management of corneal endothelial dysfunction. Descemet membrane endothelial keratoplasty (DMEK) is a relatively new corneal transplantation surgery technique suited for patients with endothelial insufficiency, an increasing number of surgeons are learning the graft preparation technique and the surgery itself after seeing its excellent postoperative visual outcomes and faster rehabilitation of patients. DMEK has significant advantages in comparison with automated and manual Descemet Stripping Endothelial Keratoplasty (DSAEK/DSEK) and PKP including lower risk of immunologic graft rejection (1-2%), lower cost of the procedure, and it does not require expensive equipment such as a microkeratome or a femtosecond laser device. Another advantage is that the corneal graft tissue can be used for several recipients - e.g. when the Descemet's membrane and endothelium are used for a patient with endothelial dysfunction of the cornea, the retained stroma and epithelium can be then used for another patient with pathology of these corneal layers. Key problematic issues regarding this surgery are the technical difficulties during graft preparation and during surgery itself, however the majority of surgeons report very good results after gaining some experience. The article reviews latest clinical trials on DMEK and describes its strengths and weaknesses.

[Mechanical dilation of the pupil and its possible applications in femtosecond laser-assisted cataract surgery]. / Mekhanicheskaia dilatatsiia zrachka i vozmozhnosti ee primeneniia v khirurgii katarakty s femtosekundnym lazernym soprovozhdeniem.

In certain cases intraoperative pupil dilation during cataract surgery may be necessary to improve the visualization of intraocular structures and assure the atraumatic nature of surgical manipulations. The article reviews a wide range of pupil expanders, their historical aspects and possibilities of their application in modern cataract surgery.

[Features of consequences of osmotic modification at different steps of cell heating]. / Osobennosti osmoticheskoi modifikatsii posledstvii razlichnoi stepeni nagreva kletok.

The influence of media with different osmotic pressure (NaCl water solutions) on survival and permeability of Escherichia coli B/r and Escherichia coli Bs-1 cells heated up to 50, 52 and 60 degrees C was investigated. Hypotonic media increased, while hypertonic media, within a certain range of sodium chloride concentrations, decreased the damaging action of heating independently of the temperature. The effectiveness of thermoprotection was seen to increase, and the range of osmolyte concentrations, at which the highest effect of protection takes place, to move markedly towards higher concentrations of NaCl with increase in heating temperature. A certain relationship is suggested between the observed phenomenon and the osmotic homeostasis system of microorganisms under condition of thermogenic and tonic stress.