Damian Czepita

Prevalence of myopia and hyperopia in a population of Polish schoolchildren

Purpose:  The aim of this study was to determine the prevalence of myopia and hyperopia in a population of Polish schoolchildren.

Speed of Visual Sensorimotor Processes and Conductivity of Visual Pathway in Volleyball Players

Speed of Visual Sensorimotor Processes and Conductivity of Visual Pathway in Volleyball Players Volleyball is a dynamic game which requires a high level of visual skills. The first aim of this study was to investigate the several aspects of reaction times (RT) to visual stimuli in volleyball players (12) compared to non-athletic subjects (12). By using the tests included in the Vienna Test System (Schuhfried, Austria), simple reaction time (SRT), choice reaction time (CRT) and peripheral reaction time (PRT) were examined. The second aim of this study was to assess the neurophysiological basis of early visual sensory processing in both examined groups. We measured two sets of pattern-reversal visual evoked potentials (VEPs) during monocular central field stimulation (Reti Scan, Roland Consult, Germany). The latencies of waves N75, P100 and N135 were determined. We observed significantly shorter (p<0.05) total reaction time to stimuli appearing in the central and peripheral field of vision in the volleyball players compared to non-athletes. With regard to SRT and CRT the main differences between the groups appeared in pre-motor reaction times. Volleyball players had shorter VEPs P100 wave latencies (p<0.05) than the non-athlete group. The results indicate faster signal transmission in visual pathways in athletes than in non-athletes. This fact can be attributed to the effect of rapid visual-activity-demanding sports on the central nervous system.

Demodex folliculorum and Demodex brevis in healthy and immunocompromised patients

Abstract Purpose: To examine the proportion of Demodex folliculorum and D. brevis in the eyelashes of healthy and immunocompromised patients. Methods: Eyelashes were taken from 95 patients at the Pomeranian Medical University, Clinic of Haematology, and from 1091 healthy controls. Results: Demodex folliculorum and D. brevis were found in 22.9% of controls and in 20% of immunocompromised patients. In neither the control group nor the immunocompromised patients did we observe a correlation between the proportion of symptoms of blepharitis and the presence of Demodex spp. – symptoms including burning sensations, loss of eyelashes, sensitivity to light, smoke and dust, dacryorrhea (excessive flow of tears), and foreign body eye sensation. A correlation between itching eyes and Demodex spp. infection was found only in the control group. A correlation between the proportion of cylindrical dandruff in eyelashes and the occurrence of Demodex spp was found in both the control group and immunocompromised patients. Conclusion: Proportions of D. folliculorum and D. brevis, and also symptoms of blepharitis were similar in the control group and immunocompromised patients. Immunosuppression did not seem to increase the rate of Demodex spp. infection.

The effect of progressively increased physical efforts on visual evoked potentials in volleyball players and non-athletes

Abstract We assessed the effect of physical effort with increasing intensity on neural activity in the visual pathway in volleyball players (n = 10) and non-athletes (n = 10). Participants performed three 10-min tests of increasing intensity on a cycle ergometer. Each participant was assigned individual workloads below the lactate threshold (40% [Vdot]O2max), at the lactate threshold (65–75% [Vdot]O2max), and above the lactate threshold (80% [Vdot]O2max). Four recordings of visual evoked potentials were made: pre-exercise and immediately after each of the three subsequent tests. We assessed neural activity of the visual pathway by examining the amplitude and latency of the N75, P100, and N135 components of the visual evoked potentials waveform. Pre-exercise P100 wave latency was shorter (P < 0.05) in volleyball players than in non-athletes. In non-athletes, the latency of P100 following the first and second effort (40% and 65–75% [Vdot]O2max) was reduced compared with pre-exercise (P < 0.01). However, P100 latency increased and P100 amplitude decreased after the third test (80% [Vdot]O2max) in non-athletes. In contrast, no significant changes in the latency or amplitude of visual evoked potentials were observed in the athletes in the three tests. Neural conductivity in the visual pathway after exercise might be at least partially dependent on the individuals personal training adaptation status.

Role of Demodex folliculorum in the pathogenesis of blepharitis.

Editor, T he ectoparasite Demodex folliculorum (Simon 1843) is most common parasite of humans. In the eye, D. folliculorum is found in the eyelash follicle. The aim of this study was to examine the prevalence of D. folliculorum in the eyelashes in patients with haematologic disorders. Eyelashes were collected from 95 patients of the Clinic of Haematology Pomeranian Medical University, Szczecin, Poland, and from 1091 healthy controls. There were 47 (49%) women and 48 (51%) men in the patients group (age range: 58.6 ± 13.1) and 759 (69.6%) women and 332 (30.4%) men in the control group (age range: 58.6 ± 13.0). From each patient, we aseptically collected two lashes from the upper right eyelid and two lashes from the upper left eyelid. The collected material was used in preparations examined using light microscopy (magnified 100 times). Infection of the examined subjects was confirmed by the detection of adult and larval forms of D. folliculorum. Demodex folliculorum is found in 21.8% of healthy controls and 18.9% of haematologic patients (Fig. 1; Table 1). In the control group, D. folliculorum occurred in 22.3% of women and in 20.8% of men. In patients with haematologic disorders, D. folliculorum occurred in 17.5% of women and in 25% of men. A much lower rate of infestation of D. folliculorum (12%) was found in immunosuppressed patients with rheumatoid arthritis (Ciftci et al. 2006). On the other hand, in patients with final-stage renal failure (ESRF) on dialysis treatment, D. folliculorum found in 44.4% of patients (Karincaoglu et al. 2005). In our study, the percentage of D. folliculorum infestation in haematologic patients ranged from 16% of patients with acute leukaemia, MPS and other haematologic diseases, and 21.7% with multiple myeloma, to about 24.1% in patients with nonHodgkin’s lymphoma and CLL. Seyhan et al. (2004) found D. folliculorum in the skin of patients with acute lymphocytic leukaemia (12%), acute myelocytic leukaemia (32%), chronic lymphocytic leukaemia (4%), chronic myelocytic leukaemia (10%), Hodgkin’s lymphoma (4%) and nonHodgkin’s lymphoma (38%). Demodex folliculorum seem to be a mediator of chronic blepharitis; some recommend that mites be sought in cilia of chronic blepharitis patients (Czepita et al. 2007). Elevated subjective symptoms of the ocular surface were caused by increased levels of D. folliculorum. Itching, burning, foreign body sensation, crusting and redness of the lid margin, and blurry vision are the main symptoms. Signs include disorders of eyelashes, lid margin inflammation, meibomian gland dysfunction, blepharoconjunctivitis and blepharokeratitis (Czepita et al. 2007). In the control group, the most common symptoms related to D. folliculorum infestation included sensitivity to light, dacryorrhea and itching of the eyelids; loss of eyelashes was the least common. In the group of haematology patients, dacryorrhea was most frequent, without any reports of sensitivity to smoke, light, foreign body sensation under the eyelids or loss of eyelashes. A 61.7% of D. folliculorum-infected patients in the ophthalmology clinic reported itching, and 59.1% reported red eyes (Inceboz et al. 2009). In our study, we found that D. folliculorum infestation was correlated with cylindrical dandruff in the lash roots, both in the control group and in haematologic patients. In patients with D. folliculorum infestation in eyelashes, we found trichiasis, meibomian gland dysfunction with lipid tear deficiency and conjunctival inflammation (Czepita et al. 2007). The prevalence of D. folliculorum in patients with haematologic diseases was similar to that of the control group. Demodicosis may cause itchiness in the eyelids and cylindrical dandruff in the lash roots.

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.

Effects of physical effort on neuroretinal function in athletes and non-athletes: an electroretinographic study

Purpose. Physical exertion may disturb retinal function. We wondered whether different levels of physical performance could affect the plot of neuroretinal activity after dynamic exercise in healthy subjects. The aim of our study was to estimate the effect of increasing intensity physical exercise on retinal activity in 2 groups: athletes (n=10) and non-athletes (n=10). Methods. We analyzed the amplitude and implicit time of b-wave electroretinogram (ERG) responses for a photopic white 30-Hz flicker stimulus. Using a cycloergometer, 3 10-minute effort tests with increasing intensity were performed. Each participant was attributed an individual workload value (W) below his lactate threshold (40% VO2max), at his lactate threshold (65%-75% VO2max), and above his lactate threshold (80% VO2max). Five ERG recordings were taken: before the efforts (first), immediately after the 3 consecutive efforts (second to fourth), and 1 hour after the last effort (fifth). Results. After the first effort, in both groups we observed a statistically significant increase in b-wave amplitude (p<0.05), and in non-athletes a decrease in implicit time of b-wave (p<0.05). After the last effort, we observed a decreased b-wave amplitude in non-athletes, whereas in athletes the amplitude remained at a high level. Conclusions. Physical effort significantly differentiated the plot of b-wave amplitude changes between athletes and non-athletes. These findings suggest that strenuous physical effort may disturb signal transfer in the inner retinal layer in non-athletic subjects. The ERGs may be used as a neurophysiologic indicator in defining the cardiovascular training status of an athlete.

Blepharitis and Demodex spp. infection

According to the latest reports Demodex mites appear to play an important role in the pathogenesis of chronic blepharitis. Demodex mites are cosmopolitan and are present in many species of mammals. In this paper we describe two species that are found in humans: Demodex folliculorum and D. brevis . Infection occurs during direct contact with an affected person and also through contact with dust containing eggs of the parasite, through contact with bed linen, as well as cosmetics used together with an affected person. Treatment of chronic blepharitis caused by D. folliculorum and D. brevis is difficult and time consuming. Some improvement can be achieved after topical application of yellow mercury ointment, sulphuric ointment, camphor oil, crotamiton, cholinesterase inhibitors, sulfacetamide, steroids, antibiotics and antifungal drugs. Good results have been achieved with oral ivermectin and permethrin cream. However, the best results were observed after treatment with metronidazole.

The role of reading, writing, using a computer, or watching television in the development of myopia

INTRODUCTION. The purpose of our investigation was to evaluate in a Polish population the role of reading, writing, using a computer, or watching television in the development of myopia. MATERIALS AND METHODS. In total 5601 students (2688 boys and 2913 girls, 6–18 years of age, mean 11.9 + 3.2 years) were examined. The children examined were Polish students of elementary and secondary schools. In every student cycloplegia after 1% tropicamide was performed. Non-parametric tests were used due to the SE distribution being significantly different from normal distribution in Kolmogorow-Smirnov test. Spearman rank correlation coefficient (Rs) was used to evaluate the strength of correlation between these variables. General linear model was used for multivariate analysis. A P-value less than 0.05 was considered significant. RESULTS. It has been established that with the increase in time spent on reading and writing, the spherical equivalent (SE) of the examined students decreases (Rs = –0.16, p < 0.000001). It was observed that an increase in the time spent working on a computer correlates with the decrease of the SE (Rs = –0.11, p < 0.000001). No relationship between watching television and the spherical equivalent of the examined schoolchildren was found (Rs = +0.01, p = 0.31). CONCLUSIONS. Reading, writing, or using a computer may lead to the development of myopia. Watching television has no influence on the incidence of myopia.

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/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.