A Clinical Case of Two-Stage Visual-Functional Rehabilitation of a Patient with Postinfectious Central Corneal Opacity in Combination with Mixed Astigmatism Using Laser Keratorefractive Surgery

Introduction: to evaluate the clinical and functional results of two-stage treatment in a patient with post-infectious Central corneal opacity combined with mixed astigmatism.Patient and methods. Patient N., 19 years old with postinfectious (postherpetic) Central corneal opacity, mixed astigmatism was examined and operated using two-stage corneal laser treatment. To determine the possibility of surgical treatment of the patient, a complex of General ophthalmology was performed (checking visual acuity near and far in natural conditions and in conditions of drug-induced mydriasis, IOP measurement, autorefractometry, examination of visual fields, A- and Bscanning, ophthalmoscopy with examination of the Central and peripheral areas of the fundus), as well as special (keratopography and Scheimpflug camera examination, optical coherence tomography (OCT) of the anterior segment of the eye with analysis of the epithelial map, quantitative assessment (Schirmer test-1) and qualitative (tear film rupture time) lachrymal products, assessment of the epithelium state when stained with vital dyes and infrared meibography) research methods. To determine the activity of herpetic infection, PCR diagnostics were performed. The follow-up period was 2 years.Results and discussion. To achieve high visual-functional rehabilitation while preserving the native lens, a two-stage treatment algorithm was developed using technologies of laser corneal refractive surgery. At the first stage, in order to regularize the ocular surface and eliminate Central corneal opacity, an inverted topographically oriented PRK was performed; at the second stage, residual refractive errors were corrected using topographically oriented FemtoLASIK technology.Conclusion. According to the results of a literature search and analysis of Internet resources, there were no previously recorded and published works using a similar two-stage method. Therefore, the described clinical case justifies the relevance and novelty of the goal and has an evidence-based Foundation for the use of a two-stage laser keratorefractive treatment system in the ophthalmological practice of visual and functional rehabilitation of patients with Central corneal opacity in combination with mixed astigmatism or hypermetropic refraction. The two-year postoperative follow-up period showed stable and high visual-functional results with no recurrence of the inflammatory process.

Dry eye syndrome in patients with gout

Purpose. To determine and study the features of the development of dry eye syndrome (DES) in gout, depending on urate-lowering therapy, the duration of the gout disease and the concentration of uric acid in the tear. Material and methods. The study involved 149 male patients (261 eyes) aged 35 to 75 years (mean age 60.63 ± 11.00 years). Among them, 110 people (202 eyes) with an established diagnosis: "Cataract with concomitant gout disease" and 39 people (59 eyes) with cataracts without clinical and laboratory signs of gout. All patients underwent both standard ophthalmological examinations and special ones. The concentration of uric acid in tears was determined by high performance liquid chromatography (HPLC). The diagnosis of gout was confirmed according to the criteria recommended by ACR / EULAR (2016). Results. In patients with gout who do not take a urate-lowering drug, DES occurs more often (82.1%) than in patients without gout (23.1%). With an increase in the concentration of uric acid in the tear, there is a high tendency to a shortening of the tear film rupture time (strong correlation coefficient r=-0.51, p<0.001) and to a decrease in tear production (Schirmer I test) (strong correlation coefficient r=-0.59, p<0.001). Conclusion. The data obtained indicate clear changes in the functional parameters of total tear production (Schirmer I's test) and the stability of the pre-corneal tear film (Norn's test) in patients with gout. This can be considered as a fact of the predisposition of this category of patients to the development of DES. A strong dependence of changes in tear production and HRVP on the concentration of uric acid in the tear was established. There is an obvious need for additional examination of this category of patients and an adequate choice of therapy, as well as the timely appointment of "artificial tear" drugs. Key words: dry eye syndrome, uric acid, gout.

Usage of 0.4% sodium hyaluronate in complex treatment of pediatric patients with dry eye syndrome against the background of allergic diseases of the organ of vision

Background. In recent years, the prevalence of allergic diseases of the anterior chamber of the eye has increased. They are often accompanied by the development of dry eye syndrome, which can complicate their course. Therefore, it is important to take a comprehensive approach to their diagnosis and treatment. The purpose was to study the effectiveness of 0.4% sodium hyaluronate (Gilays) in children with dry eye syndrome on the background of allergic diseases of the conjunctiva. Materials and methods. The study involved 42 patients (84 eyes) aged 3 to 18 years, who were examined and treated on the basis of Regional Eye Clinic. Patients were treated with local H-1 histamine blockers twice a day for 14 days, f necessary — with topical glucocorticoids by the scheme for 12 days. In the first group (21 patients, 42 eyes), the main treatment was added with the drugs containing 0.2% sodium hyaluronate, used topically 4 times a day for 14 days. In the second group (21 patients/42 eyes), 0.4% sodium hyaluronate (Gilays) was added to the treatment regimen. H-1 histamine blockers were not used systemically. Before starting therapy and 2 weeks later, the following values were evaluated: the changes in the anterior chamber of the eye using biomicroscopy, determination of lacrimal film rupture time, Schirmer 1 test, questionnaire. Conclusions. The use of sodium hyaluronate in the complex therapy of dry eye syndrome in allergic eye diseases is quite effective. The use of 0.4% sodium hyaluronate was more effective compared to the control group. It is advisable to use a questionnaire to communicate with the child, but it is necessary to refine the form of questions to eliminate as much as possible the subjectivity of the data.

Dropwise Condensation Mechanism on Smooth Hydrophilic Surfaces

The objective of this work is to identify the mechanism of dropwise condensation on a smooth solid surface. We investigate the stable dropwise condensation that occurs at a droplet growth rate of 1 µm/s in diameter on a gold-coated glass surface. Additionally, we present our observations on unstable dropwise condensation, i.e., degradation of dropwise condensation of steam on a gold surface. Surface Plasmon Resonance Imaging (SPRi) is used to evaluate the existence and structure of thin films and occurrence of initial nuclei during condensation. SPRi approach used in this study has lateral resolutions of 4–10 µm, thickness resolutions of 0.1–1 nm, and temporal resolutions of 200–10,000 frames per second (FPS). Visualization of the onset of stable dropwise condensation suggests droplets form at heterogeneous nucleation sites and that no film greater than a monolayer exists on the surface before the formation of droplets. Observation of the unstable dropwise condensation of steam shows the existence of water films that are several nanometers thick between droplets. This work shows that neither the nucleation theory nor film rupture theory can individually explain the physics of dropwise condensation. Therefore, there is a need for a more comprehensive theory that can explain the mechanism of dropwise condensation.

Dropwise Condensation Mechanism on Smooth Hydrophilic Surfaces

The objective of this work is to identify the mechanism of dropwise condensation on a smooth solid surface. We investigate the stable dropwise condensation that occurs at a droplet growth rate of 1 µm/s in diameter on a gold-coated glass surface. Additionally, we present our observations on unstable dropwise condensation, i.e., degradation of dropwise condensation of steam on a gold surface. The Surface Plasmon Resonance Imaging (SPRi) approach used in this study has lateral resolutions of 4-10 µm, thickness resolutions of 0.1-1 nm, and temporal resolutions of 200-10,000 frames per second (FPS). SPRi is used to evaluate the existence and structure of thin films and occurrence of initial nuclei during condensation. Visualization of the onset of stable dropwise condensation suggests droplets form at heterogeneous nucleation sites and that no film greater than a monolayer exists on the surface before the formation of droplets. Observation of the unstable dropwise condensation of steam shows the existence of water films that are several nanometers thick between droplets. This work shows that neither the nucleation theory or film rupture theory can individually explain the physics of dropwise condensation. Therefore, there is a need for a more comprehensive theory that can explain the mechanism of dropwise condensation.

Choosing the optimal method for preoperative risk assessment of dry eye syndrome development in patients with myopia

Aim. Comparative analysis of the effectiveness of keratotopography methods and classical Norn’s test in assessing the stability of the tear film (TF) in patients with myopia before photorefractive surgery. Methods. The study involved 26 patients. All of them were planned for keratorefractive surgery to correct myopic refraction and astigmatism. Their age averaged 32.5±14.5 years (18-47 years). The stability of pre-corneal tear film was assessed using computed keratotopography and Norn’s test - the tear film rupture time (TFRT) was determined. A standard questionnaire was also used to assess the severity of symptoms of dry eye syndrome (DES). A comparison was made of the indicators of tear film, stability obtained by the methods of keratotopography and Norn’s test, with their subsequent comparison with the data of the questionnaire. Results. In 17 patients (65.4 %), TFRT index corresponded to the age norm. In the remaining 9 people (34.6 %), indicators of tear film stability were reduced both by keratotopography (12±4 sec) and by Norn’s test (13.5± 4.5 sec), and there were also subjective signs of dry eye syndrome according to questionnaire data. The data turned out to be comparable. Conclusion. The incidence of impaired stability of the TF and subjective manifestations of DES among patients planned for keratorefractive surgery for myopia and myopic astigmatism was significant and, according to our data, made 34.6 %. To prevent complicated postoperative course of photorefractive surgery, it is necessary to assess the condition of the ocular surface immediately before refractive surgery, to identify the risk group for DES development. Key words: dry eye syndrome; tear film; keratotopography; Norn’s test; tear film rupture time.

A Combined Pulse Driving Waveform With Rising Gradient for Improving the Aperture Ratio of Electrowetting Displays

As a reflective display technology, electrowetting displays (EWDs) have the advantages of paper-like display, low power consumption, fast response, and full color, but the aperture ratio of EWDs is seriously affected by oil dispersion and charge trapping. In order to improve the aperture ratio and optimize the display performance of EWDs, a combined pulse driving waveform with rising gradient design was proposed. First, an initial driving voltage was established by the threshold voltage of oil film rupture (Vth). And then, a rising gradient was designed to prevent oil from dispersing. At last, the oil splitting and movement were controlled to achieve the target aperture combined with the pulse waveform. Experimental results showed that the oil dispersion of EWDs can be effectively improved by using the proposed driving waveform, the aperture ratio of EWDs was increased by 3.16%, and the stability was increased by 71.43%.

Features of the development of dry eye syndrome with gout

Purpose. To determine and study the features of the development of dry eye syndrome in gout, depending on urate-lowering therapy, the duration of the gout disease and the concentration of uric acid in the tear. Materials and methods. The study involved 149 male patients (261 eyes) aged 35 to 75 years (mean age 60.63 ± 11.00 years). Among them, 110 people (202 eyes) with an established diagnosis: «Cataract with concomitant gout disease» and 39 people (59 eyes) with cataracts without clinical and laboratory signs of gout. All patients underwent both standard ophthalmological examinations and special ones. The concentration of uric acid in tears was determined by high performance liquid chromatography (HPLC). The diagnosis of gout was confirmed according to the criteria recommended by ACR / EULAR (2016). Results. In patients with gout who do not take a urate-lowering drug, DES occurs more often (82.1%) than in patients without gout (23.1%). With an increase in the concentration of uric acid in the tear, there is a high tendency to a shortening of the tear film rupture time (strong correlation coefficient r=-0.51, p<0.001) and to a decrease in tear production (Schirmer I test) (strong correlation coefficient r=-0.59, p<0.001). Conclusions. The data obtained indicate clear changes in the functional parameters of total tear production (Schirmer I's test) and the stability of the pre-corneal tear film (Norn's test) in patients with gout. This can be considered as a fact of the predisposition of this category of patients to the development of DES. A strong dependence of changes in tear production and HRVP on the concentration of uric acid in the tear was established. There is an obvious need for additional examination of this category of patients and an adequate choice of therapy, as well as the timely appointment of «artificial tear» drugs. Key words: dry eye syndrome, uric acid, gout.