Demodex Species and Culturable Microorganism Co-Infestations in Patients with Blepharitis.

We aimed to determine the prevalence of Demodex spp. and bacterial infection in patients with blepharitis and also to investigate the relationship between culturable microorganisms and Demodex spp. in this study. The study included patients diagnosed with blepharitis (n = 128) and volunteers without ocular problems (n = 113). Eyelash sampling was performed by epilating eight lashes, which were then tested for Demodex spp. using a light microscope. The examination consisted of assessing the patient's vision with and without ocular correction and tonus in both eyes and a careful examination of the anterior segment of both eyes. Bacterial identification was performed based on morphological, physiological, and biochemical methods. The prevalence of Demodex spp. was 8.0% in patients from the control group and all patients with blepharitis. Isolated forms of Demodex spp. were detected in all infested patients in the control group and in 58% of patients with blepharitis. A total of 35% of patients with blepharitis had from three to nine forms of Demodex spp., and 7% of patients with blepharitis had more than 10 mites in every field of vision. We found a statistically significant relationship between Demodex spp. infestation and the occurrence of eye dryness and sensations of burning and tearing, redness of the conjunctiva, feeling of a foreign body, loss of eyelashes, Meibomian gland dysfunction, and cylindrical dandruff. There were statistically significant relationships between Demodex sp. infestation and the presence of hyperopia, Meibomian cysts, chronic eyelid inflammation, and the use of eyeglasses. There was also a statistically significant relationship between the occurrence of Demodex spp. and seborrheic dermatitis and diabetes mellitus. Culturable microorganisms of the ocular surface were found in 8.7% of participants who were uninfested and in all patients infested with D. folliculorum. We isolated Staphylococcus aureus, Acinetobacter baumannii, Streptococcus pneumoniae, Klebsiella oxytoca, and Bacillus spp. from the conjunctival sac only in patients infested with D. folliculorum. This indicates an increased probability of colonization by pathogenic bacteria in patients with demodicosis. Therefore, patients infested with D. folliculorum should undergo a microbiological examination of conjunctival swabs.

Aperture photometry measurements of melanin particles in Krukenberg spindles of the cornea in pigment dispersion syndrome.

BACKGROUND: Quantification of melanin pigment release in pigment dispersion syndrome as well as observations of melanin brightness changes can be valuable information in the management of this rare ocular disease. OBJECTIVES: Previous studies have focused on examining the iris pigment epithelium and aqueous humor. Therefore, the aim of this study was to examine the cornea. METHODS: A novel technique was developed for this purpose based on aperture photometry. Slit lamp digital video images of the cornea were recorded. A single frame from each video recording based on the quality was chosen for further processing and analysis. Aperture photometry was performed with AstroImageJ open source software. Aperture selection was performed automatically. Melanin particles displaying a signal-to-noise ratio above 20 were analyzed. RESULTS: A total of 16 melanin particles from the right eye of the patient participating in the study were detected and a further 9 melanin particles from the left eye. The examined area of the cornea measured 348 × 348 pixels in the image. Brightness differed by as much as 8.98 × among particles in the right eye and 2.03 × in the left eye. CONCLUSIONS: It seems feasible for this new method to be potentially used in the monitoring of patients with pigment dispersion syndrome and pigmentary glaucoma as well as in other ocular diseases.

Image processing pipeline for the detection of blood flow through retinal vessels with subpixel accuracy in fundus images.

BACKGROUND AND OBJECTIVE: Blood flow detection through the retinal vessels is an essential step in diagnosing several eye diseases. It manifests itself as changes in vessel diameter in consecutive phases of blood flow. Previous studies focused mainly on determining retinal vessel diameter by the manual demarcation of vessel edges, which is time-consuming. As a result, only a few selected vessels were considered, which is not reliable. Such measurements are also prone to human errors and operator subjectivity, which additionally decreases their reliability. For these reasons, this paper proposes an automated pipeline to analyze the blood flow through retinal vessels. METHODS: Convolutional neural networks were used for optic disc and vessel detection and full width at half maximum analysis used for vessel width assessment at the subpixel level. Measurements of the diameter were performed for five phases of the blood flow to all vessels at a particular distance derived from the optic disc size. We tested the approach on fundus images of five patients, with both eyes examined in each participant. The threshold for the detections of blood flow was when the retinal diameter vessel measurements were above the camera's resolution as compared among all 5 phases of blood flow. RESULTS: A total of 205 large caliber blood vessels were analyzed with blood flow detected in 18 retinal blood vessels. Conclusions Average vessel diameters derived from manual and automatic measurements differed on average by 4.96%. Average relative errors for single vessel measurements along the vessels range from 4.21 to 11.85%, with a global average at the level of 8%. Therefore, the measurements can be considered as accurate and in a high agreement between the expert and algorithm.

Near-infrared transillumination imaging combined with aperture photometry for the quantification of melanin in the iris pigment epithelium.

Near-infrared transillumination is used in the diagnosis and the management of different eye diseases. In particular, it enables the visualization of melanin in the pigment epithelium of the iris. This technique is valuable in such conditions as pigment dispersion syndrome and Adie's tonic pupil. Thus, objective quantification of the amount of melanin shedded from the iris pigment epithelium may help in the management of these conditions. By combining aperture photometry with near-infrared iris transillumination this can be achieved. A total of 4 patients (7 eyes) were examined. Three patients were diagnosed with pigment dispersion syndrome in both eyes. One patient had Adie's tonic pupil in one eye. Near-infrared iris transillumination was performed by using a prototype apparatus. Aperture photometry measurements were carried out through specially developed software. The signal-to-noise ratio of the prototype apparatus was 52 dB (399:1). Each pixel within the near-infrared transillumination image corresponded with an area size of the iris of 85 µm x 83 µm. Measurements were taken from several points of the iris in all patients. The average aperture photometry value of transillumination defects was 1321.53 (ADU) ± 501.08 SD, while the average aperture photometry value of the papillary ruff was 90.83 (ADU) ± 53.4. On average transillumination defects transmit 14.55 times more near-infrared light than the papillary ruff. A prototype apparatus for the capture of near-infrared iris transillumination images and custom software enabling aperture photometry measurements of the obtained images has been developed for the purpose of this study. This study demonstrates a potential application of this technique in the diagnosis and management of patients with such conditions as pigment dispersion syndrome and Adie's tonic pupil.

Role of Gender in the Prevalence of Myopia among Polish Schoolchildren.

PURPOSE: The aim of the paper was to study the role of gender in the progression of myopia among Polish schoolchildren. MATERIALS AND METHODS: 4875 children from elementary schools and high schools were examined (2470 boys, aged 6-16 years, mean age 11.0, SD = 2.6 and 2405 girls, aged 6-16 years, mean age 11.1, SD = 2.6). The examined students were Caucasian and resided in and around Szczecin, Poland. The examination included retinoscopy under cycloplegia. The refractive error readings were reported as spherical equivalent (SE). Myopia was defined as SE of at least -0.5 D. Data analysis was performed using the Mann-Whitney U test and 2-sided Fisher's exact test. p values of less than 0.05 were considered statistically significant. RESULTS: It was found that the SE among Polish boys is similar to the SE among Polish girls before the age of 9 years. However, in older children, lower SE values and higher prevalence of myopia were found among girls than boys, both at 9-13 years range (0.45 ± 1.05 vs 0.55 ± 1.23 D, p=0.047 and 8.30% vs 5.71%, p=0.015, respectively) and at 13-16 years range (0.32 ± 1.14 vs 0.54 ± 1.08 D, p=0.0093 and 10.37% vs 5.96%, p=0.0050), respectively. CONCLUSIONS: Gender is associated with the prevalence of myopia among Polish schoolchildren ranging from 9 to 16 years of age.

Enhancement of Choriocapillaris Visualization in En Face Swept-Source Optical Coherence Tomography Angiography Images.

BACKGROUND Visualization of the choriocapillaris vessels using swept-source optical coherence tomography is a novel technique. However, en face images obtained with current commercial equipment using this method are still unclear. Therefore, using freely available image processing software, we have been able to enhance and clearly visualize single choriocapillaris blood vessels. MATERIAL AND METHODS We examined 4 swept-source optical coherence tomography en face images of the choriocapillaris in 2 male patients in both eyes and processed them using Image J software. RESULTS In our study, all images displayed clearly individual choriocapillaris vessels. CONCLUSIONS Implementation of this technique significantly improves visualization of the choriocapillaris. Further studies need to be carried out in order to validate this method of enhancement.

Near-infrared fundus autoflorescence imaging in solar retinopathy.

Solar retinopathy is a rare clinical entity caused by photochemical damage to the retinal pigment epithelium layer and photoreceptors of the fovea. Here we describe a case of a 33-year-old female patient diagnosed by near-infrared fundus autofluorescence imaging for signs of damage to the melanosomes of the retinal pigment epithelium of the fovea. The patient was advised to discontinue looking at the sun with the naked eye.

The Influence of Environmental Factors on the Prevalence of Myopia in Poland.

PURPOSE: In the paper, we describe and discuss the results of epidemiological studies concerning myopia carried out in Poland. MATERIALS AND METHODS: Results from the examination of 5601 Polish school children and students (2688 boys and 2913 girls) aged 6 to 18 years were analyzed. The mean age was 11.9 ± 3.2 years. Every examined student had undergone the following examinations: distance visual acuity testing, cover test, anterior segment evaluation, and cycloplegic retinoscopy after instillation of 1% tropicamide, and a questionnaire was taken. RESULTS: We have found that (1) intensive near work (writing, reading, and working on a computer) leads to a higher prevalence of myopia, (2) watching television does not influence the prevalence of myopia, and (3) being outdoors decreases the prevalence of myopia. CONCLUSIONS: The results of our study point to insufficiency of accommodation contributing to the pathogenesis of myopia.

The role of outdoor activity in the development of myopia in schoolchildren.

Introduction: The aim of our study was to examine whether outdoor activity influences the prevalence of myopia in schoolchildren. Materials and methods: 5601 Polish students of elementary and secondary schools (2688 boys and 2913 girls), 6­18 years of age (mean 11.9 ±3.2 years) were examined. In every student cycloplegia after 1% tropicamide was performed. The mean spherical equivalent (SE) was calculated after examination of both eyes. Time spent on outdoor activity was evaluated based on a questionnaire. The obtained results were typed into an Excel spreadsheet and analyzed statistically using Statistica 10 software. Non-parametric tests were used due to the SE distribution being significantly different from normal distribution in the Kolmogorov­Smirnov test. The Spearman rank correlation coefficient (Rs) was used to evaluate the strength of the correlation between these variables. A p-value less than 0.05 was considered significant. Results: It has been established that with the increase in time spent on outdoor activity, the spherical equivalent of the examined students significantly increases, but the correlation is very weak (Rs = +0.036, p = 0.007). Conclusion: Outdoor activity slightly reduces the prevalence of myopia in schoolchildren.

Aqueous levels of VEGF correlate with retinal non-perfusion areas in patients with diabetic macular edema and macular edema secondary to central retinal vein occlusion.

AIM: To evaluate the association between the level of vascular endothelial growth factor in the aqueous humor and the size of capillary non-perfusion areas in patients with macular edema secondary to retinal vein occlusion and diabetic retinopathy. MATERIAL AND METHODS: The study group consisted of 24 patients (24 eyes) at the age of 55-78 years, with diffuse macular edema secondary to retinal vein occlusion and diabetic retinopathy. The control group consisted of 26 subjects aged 55-87 years who were admitted for scheduled cataract surgery. The VEGF aqueous humor levels, retinal thickness using optical coherence tomography, as well as the size of non-perfusion areas measured on fluorescein angiography images were evaluated in each enrolled subject. RESULTS: The vascular endothelial growth factor aqueous humor levels were found to be significantly higher in patients with macular edema as compared to controls (p = 0.0002). In the diabetic macular edema and retinal vein occlusion group, the con- centration of vascular endothelial growth factor in aqueous humor positively correlated with the extent of non-perfusion areas measured on fluorescein angiograms (Rs = + 0.45, p = 0.02;). Multivariate analysis of patients and controls performed using the general linear model, adjusted for age, sex, intraocular pressure and the presence of diabetes, revealed that macular edema was an independent factor associated with higher aqueous VEGF concentrations (ß = +0.74, p = 0.0012). CONCLUSIONS: Macular edema secondary to either retinal vein occlusion or diabetic retinopathy is associated with the increased levels of vascular endothelial growth factor in the aqueous humor. Therefore, the management of patients with macular edema secondary to retinal vein occlusion or diabetic retinopathy should aim at reducing the ocular vascular endothelial growth factor concentrations, especially in the presence of capillary non-perfusion areas.

Macular Pigment Optical Density and Ocular Pulse Amplitude in Subjects with Different Axial Lengths and Refractive Errors.

BACKGROUND: The purpose of our study was to: (1) investigate the macular pigment optical density (MPOD) and ocular pulse amplitude (OPA) in subjects with different axial lengths (AL) and refractive errors (RE); (2) determine if there is a correlation between MPOD and OPA; and (3) evaluate whether MPOD and OPA depend on intraocular pressure (IOP). MATERIAL AND METHODS: This study included 140 eyes of 70 subjects - 17 men and 53 women, aged 18 to 29 years (mean: 22.5 years; SD=2.8). Every examined person underwent a thorough eye examination including: visual acuity, anterior segment and fundus examination, keratometry, auto-refractometry, and MPOD, OPA, AL, and IOP measurements. The obtained results were analyzed statistically using Statistica 10 software. P values of <0.05 were considered statistically significant. RESULTS: The following refractive errors were selected: emmetropia (34 eyes), hyperopia (18 eyes), low myopia (60 eyes), medium myopia (19 eyes), and high myopia (9 eyes). It has been established that the OPA increases with the rise in the spherical equivalents (SE) (Rs=+0.38, P<0.001), while the increase in AL correlates with the decrease of OPA (Rs=-0.40, P<0.001). The increase in IOP correlates with the rise in the OPA (Rs=+0.20, P<0.05). There were no significant correlations between IOP and SE or AL. CONCLUSIONS: (1) MPOD is not correlated with the OPA in subjects with different AL and RE; (2) OPA decreases with the rise of AL; (3) OPA decreases with the fall of the SE; and (4) OPA increases with the rise in IOP.

Does the month of birth influence the prevalence of refractive errors?

PURPOSE: The aim of our study was to examine whether the month of birth influences the prevalence of refractive errors. MATERIAL AND METHODS: A total of 5,601 schoolchildren were examined (2,688 boys and 2,913 girls, aged 6-18 years, mean age 11.9, SD 3.2 years). The children examined, students of elementary and secondary schools, were Polish and resided in and around Szczecin, Poland. Every examined subject underwent retinoscopy under cycloplegia using 1% tropicamide. Data analysis was performed using the Kruskal-Wallis test followed by the Siegel and Castellan post-hoc test or the Mann-Whitney U-test. P values of < 0.05 were considered statistically significant. RESULTS: Students born in June had significantly higher spherical equivalents than schoolchildren born in May (0.66 ± 1.17 and 0.39 ± 1.17 respectively, p = 0.0058). The Mann-Whitney U-test showed that students born in June had significantly higher spherical equivalents than schoolchildren born in any other month (0.66 ± 1.17 and 0.50 ± 1.17 respectively, p = 0.0033). Besides that, we did not observe any other association between refractive errors and the month of birth. CONCLUSION: Children born in Poland in June may have a higher spherical equivalent.

THE INFLUENCE OF READING AND WRITING ON THE PREVALENCE OF MYOPIA.

PURPOSE: In this study we decided to answer the question of whether spending more time on reading and writing leads to higher prevalence of myopia. MATERIAL AND METHODS: A total of 70 people (140 eyes)--17 men and 53 women aged 18-29 years (mean 22.5 ± 2.8) were examined. A questionnaire concerning the amount of time spent each day on reading and writing, as well as ophthalmic examination involving: visual acuity, anterior segment and fundus examination, keratometry, autorefractometry and axial length of the eyeball measurement (using IOL Master) were carried out in all participants. The refractive errors were described as spherical equivalents (SE). Hyperopia was defined to be SE higher than +0.5 Dsph, and emmetropia to be higher than -0.5 and lower than +0.5 Dsph. Myopia was defined to be with a SE lower than -0.5 Dsph. High myopia was defined as SE lower than -8, medium myopia in the range between -8 and -4, and low myopia lower than -0.5 and higher than -4 Dsph. The obtained results were typed into an Excel spreadsheet and analyzed statistically using Statistica 10 software. P values of < 0.05 were considered statistically significant. RESULTS: It was found that people with low myopia spent statistically more time on reading and writing than participants in the emmetropic group (5.8 ± 2.4 vs 4.1 ± 2.4 h/day, p = 0.003). A relationship between reading and writing and medium and high myopia and hyperopia was not observed (p > 0.05). CONCLUSION: Near visual work leads to higher prevalence of low myopia.

Myopia and night lighting. Investigations on children with negative family history.

PURPOSE: The aim of our study was to investigate if ambient lighting at night before the age of 2 years is associated with the occurrence of myopia in a large population of Polish children. To eliminate the influence of genetic factors, only children with a negative family history of myopia were included. MATERIAL AND METHODS: A total of 3905 students, all of whom had a negative family history of myopia were examined (1800 boys and 2105 girls, aged 6-18 years, mean age 12.2, S.D. 3.3 years). The examination included retinoscopy under cycloplegia with 1% tropicamide. Myopia in the subjects was defined as a spherical equivalent of at least -0.50 dioptres. The parents of all students examined completed a questionnaire on the child's family history of myopia as well as the child's exposure to light emitted by incandescent or fluorescent lamps before the age of two years. Data analysis was performed using chi-squared Pearson test; p-values of <0.05 were considered statistically significant. RESULTS: Sleeping until the age of two with a room light is not associated with the presence of myopia during school years (p>0.05). No differences in the use of light emitted by incandescent or fluorescent lamps on the prevalence of myopia was found (p>0.05). CONCLUSIONS: Myopia is not associated with night light use before age of 2 years in a population of Polish children with a negative family history of myopia. Because both, the restricted population and results differ from our previous positive associations, perhaps early light exposure and family history/genetics interact in influcencing the occurance of myopia.

Retinal degenerative diseases--mechanisms and perspectives of treatment.

Retinal degenerative diseases are an extensive group of ocular diseases, leading to vision disorders and finally irreversible vision loss. They are an significant problem, because degenerative processes exist in common ocular disorders like glaucoma or age-related macular degeneration and many other less frequently occurring disorders. In this article, we present mechanisms leading to retinal degeneration like excitotoxicity, oxidative stress, inflammation and summarize the latest reports concerning neuroprotection in the treatment of retina degenerative diseases.

The effect of genetic factors on the occurrence of myopia.

PURPOSE: The aim of this study was to investigate on a large population if and how genetic factors have an influence on the occurrence of myopia. MATERIAL AND METHODS: A total of 5533 students were examined (2659 boys and 2874 girls, in age 6 18 years, mean age 11.9, S.D. 3.2). The examination included retinoscopy under cycloplegia induced with 1% tropicamide. Myopia was defined as a spherical equivalent of at least -0.5 dioptres. The students and their parents completed a questionnaire on the child's family history of myopia. Data analysis was performed using chi-squared test; p-values of < 0.05 were considered statistically significant. RESULTS: It was found that myopia occurs more often in students whose father (p < 0.001), mother (p < 0.001) or siblings (p < 0.0001) have myopia. A relation between the occurrence of myopia in grandparents and grandchildren was not observed (p > 0.05). CONCLUSIONS: The obtained results indicate that genetic factors have a significant effect on the occurrence of myopia.

Reading, writing, working on a computer or watching television, and myopia.

PURPOSE: The aim of our study was to investigate on a large population if reading, writing, working on a computer or watching television might be associated with the occurrence of myopia. MATERIAL AND METHODS: A total of 5865 schoolchildren were examined (2792 boys and 3073 girls, at the age 6-18 years, mean age 11.9, S.D. 3.3). The examination included retinoscopy under cycloplegia induced with 1% tropicamide. Myopia was defined as a spherical equivalent of at least -0.50 dioptres. Mean refractive error was -1.2, SD 1.3. (The students and their parents completed a questionnaire on the child's visual work. Data analysis was performed using independence chi-squared Pearson test; p-values of <0.05 were considered statistically significant. RESULTS: It was observed that myopia occurs more often in students who read and write >2 hours/day (p<0.001), and also work >0.8 hours/day on a computer (p<0.01). Furthermore, no increase in the prevalence of myopia in subjects who spend >2 hours/day watching television was found (p>0.05). CONCLUSIONS: The obtained results indicate that reading, writing, working on a computer might be associated with the occurrence of myopia among schoolchildren. Watching television is not related to the occurrence of myopia.

Are children with myopia more intelligent? A literature review.

PURPOSE: Refractive errors are a serious worldwide problem. So far a few papers have described the relationship between refractive errors and intelligence. However, based on the growing interest into the relationship between refractive errors and intelligence quotient (IQ) we decided to present and discuss the latest results of the clinical studies on that subject. MATERIAL AND METHODS: A review of the literature concerning the relationship between refractive errors and IQ was done. RESULTS: In 1958 Nadell and Hirsch found that children in America with myopia have a higher IQ. A similar relationship has been described by other researchers from the USA, the Czech Republic, Denmark, Israel, New Zealand, and Singapore. In other related studies, it was reported that myopic children regardless of their IQ gain better school achievements--table 1. It was also observed that schoolchildren with hyperopia have a lower IQ and gain worse school achievements--table 2. Several hypotheses explaining the relationship between refractive errors and intelligence have been published. Recently, Saw et al. concluded that higher IQ may be associated with myopia, independent of books read per week, in schoolchildren. According to them "the association between genetically driven IQ and myopia of hereditary predisposition could be forged because of a pleiotropic relationship between IQ and myopia in which the same causal factor is reflected in both genetic traits. There may be similar genes affecting eye size or growth (associated with myopia) and neocortical size (possibly associated with IQ)". CONCLUSIONS: The conducted clinical observations suggest that children with myopia may have a higher IQ. This relationship is most probably determined by genetic and environmental factors.

Role of gender in the occurrence of refractive errors.

PURPOSE: The aim of the paper was to study the role of gender in the occurrence of refractive errors in schoolchildren ranging from 6-18 years of age. MATERIAL AND METHODS: 5865 children from elementary schools, junior high schools and high schools were examined (2845 boys, aged 6-18 years, mean age 11.4, SD = 3.0 and 3020 girls, aged 6-18 years, mean age 11.9, SD = 3.3). The examined students were Caucasian and resided in and around Szczecin, Poland. The examination included retinoscopy under cycloplegia. The refractive error readings were reported as spherical equivalent (SE). Myopia was defined as SE of at least -0.5 D, hyperopia as SE of at least +1.0 D. Astigmatism was diagnosed when the difference in the refraction of axes in one eye was > 0.5 DC. Data analysis was performed using chi2 test. P values of less than 0.05 were considered statistically significant. RESULTS: It was found that myopia occurs more frequently in girls (7.4%) than in boys (5.1%) - p < 0.001. Hyperopia occurs more frequently in boys (19.6%) than in girls (18.2%) - p < 0.001. A slightly higher prevalence of astigmatism in girls (1.9%) than in boys (1.5%) was also observed (p > 0.05). CONCLUSIONS: Gender influences the occurrence of myopia and hyperopia in schoolchildren ranging from 6-18 years of age.