Comparison of polypropylene and silicone Ahmed® glaucoma valves in the treatment of neovascular glaucoma: A 2-year follow-up.

BACKGROUND: Inflammation associated with biomaterials of Ahmed® glaucoma drainage devices may cause the formation of a capsule around the device and can thus have a significant influence on the level of intraocular pressure reduction. OBJECTIVES: The objective of this study was to compare the clinical outcomes after the implantation of a polypropylene or silicone Ahmed® glaucoma valve in patients with neovascular glaucoma. MATERIAL AND METHODS: In the study, 27 eyes with neovascular glaucoma (group 1) received silicon Ahmed® valves and 23 eyes (group 2) received polypropylene valves. The best corrected distance visual acuity (BCDVA), intraocular pressure (IOP) and number of anti-glaucomatous drugs were recorded preoperatively and during a follow-up period of 24 months after surgery. Success was defined by the following criteria: 1) intraocular pressure in the rage of 6-21 mm Hg; 2) IOP reduction of at least 30% relative to preoperative values. All complications were registered. RESULTS: One month postoperatively, the mean BCDVA increased significantly in both groups compared to preoperative values (p < 0.001). These values did not change during the 24 months of follow-up examinations. The probability of success defined by criterion 1 at 24 months of observation was 66.7% for silicone and 27.3% for propylene valves group (p < 0.007). According to criterion 2, the difference in success between the groups was not statistically significant. The total number of complications that occurred in both groups during the 24 months of follow-up examinations was similar, except for a higher occurrence of Tenon's cyst formation in the group with a polypropylene valve (18% vs 35%; p < 0.04). CONCLUSIONS: In patients with neovascular glaucoma, the implantation of a silicone valve is associated with a significantly higher probability of long-term reduction of IOP below 21 mm Hg and with a lower risk of valve encapsulation in comparison to polypropylene valves. The obtained results suggest that silicone Ahmed® valves are more effective in the treatment of patients with neovascular glaucoma.

Assessment of macular function, structure and predictive value of pattern electroretinogram parameters for postoperative visual acuity in patients with idiopathic epimacular membrane.

PURPOSE: To evaluate macular function and structure before and after epimacular membrane surgery and to estimate the usefulness of pattern ERG test parameters in predicting the postoperative visual acuity. METHODS: We evaluated 32 eyes of 32 patients (mean age 70.8 ± 6.7 years) before and 12 months after successful 25G pars plana vitrectomy with epimacular membrane removal and internal limiting membrane peeling. Distance best-corrected visual acuity (DBCVA-logMAR), foveal thickness (optical coherence tomography-OCT) and macular function [pattern electroretinogram-PERG (ISCEV standard): amplitudes (A) of P50- and N95-waves, implicit time (IT) of P50-wave] were assessed. To estimate the differences between the mean values of considered characteristics, the t test or Wilcoxon matched pair test was used. Correlation between preoperative data of PERG and preoperative and final DBCVA were investigated using Pearson correlation analysis. A receiver operating characteristic curve was constructed to obtain a cutoff value allowing prediction of visual prognosis. We tried to obtain the P50 and N95 amplitudes cutoff value in prediction of good visual outcome (DBCVA of 0.3 or less). RESULTS: Twelve months after surgery, mean of DBCVA significantly increased in comparison with preoperative value (0.31 ± 0.12 vs. 0.6 ± 0.15; p < 0.001) and 23/32 eyes (72 %) achieved visual improvement of two and more Snellen lines. In OCT test, the significant reduction in foveal thickness mean (313.34 ± 47.01 vs. 509.03 ± 93.88 µm; p < 0.001) was obtained. In PERG test, the significant increase in the mean amplitudes of P50- (AP50) and N95 (AN95)-waves as well as significant decrease in the mean implicit time (IT) of P50-wave were achieved (AP50: 3.41 ± 1.48 vs. 2.38 ± 1.23 µV; p < 0.001; AN95: 5.46 ± 1.72 vs. 3.75 ± 1.48 µV; p < 0.001; IT P50: 55.00 ± 3.60 vs. 56.75 ± 5.78 ms; p < 0.001). Twelve months postoperatively, DBCVA was significantly correlated with preoperative IT P50 (r = 0.39; p = 0.027), AP50 (r = -0.68; p < 0.001) and AN95 (r = -0.73; p < 0.001). CONCLUSION: Removal of idiopathic epimacular membranes with internal limiting membrane peeling not only provided increase in visual acuity and reduction in foveal thickness but also caused improvement of innermost retinal layer function in macular region. Pattern ERG test might be a valuable tool in predicting the postoperative visual acuity.

PARS PLANA VITRECTOMY IN ADVANCED CASES OF VON HIPPEL-LINDAU EYE DISEASE.

PURPOSE: To investigate spectrum of patients with Von Hippel-Lindau disease (VHL) that required pars plana vitrectomy and evaluate anatomical and functional outcomes of surgery. METHODS: Twenty-three patients who underwent surgery for advanced VHL eye disease were assessed by genetic tests, diagnostic tests for systemic lesions, and clinical eye examination. The vitrectomized eyes were divided into two groups: with or without retinotomy (group R vs. NR). Functional and anatomical outcome was analyzed and compared between the groups. RESULTS: All patients had central nervous system hemangioblastomas and 57% had other systemic tumors. Point germline mutations, large partial deletions, and complete vhl gene deletions were found in 64%, 27%, and 9% of patients, accordingly. Destruction of hemangioblastomas by retinotomy, laser, or cryotherapy and anatomical attachment of the retina were achieved in all eyes. Preoperative mean distance best-corrected visual acuity was logarithm of the minimum angle of resolution 2.66 (20/9,140) in group R and 1.76 (20/1,150) in group NR (P < 0.05). At 6 months postoperatively, distance best-corrected visual acuity improved in 20 eyes (83%). After over 24 months postoperatively, distance best-corrected visual acuity remained better than preoperatively in 36% in the R group and in 70% in the NR group of eyes. During 24 months postoperatively in 17 eyes, new retinal capillary hemangiomas developed. The mean number of new retinal capillary hemangiomas per eye was higher in group R than in group NR (3.14 vs. 0.70; P < 0.01). In group R, number of new retinal capillary hemangioblastoma was higher in retinal segments where retinotomy was performed (n = 29) than in other areas (n = 13) (P < 0.01). CONCLUSION: Advanced VHL eye disease correlates with occurrence of central nervous system and systemic lesions. Spectrum of vhl gene mutation in the patients corresponds to that of the general VHL population. Pars plana vitrectomy in advanced VHL eye disease can improve or preserve visual function, but postoperative progression of ocular VHL disease can be accelerated in cases where retinotomy is performed.

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.

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.

[Outcomes of surgical management of retinopathy of prematurity--an overview]. / Wyniki leczenia operacyjnego retinopatii wczesniaczej--przeglad pismiennictwa.

According to the guidelines by the ETROP (Early Treatment for Retinopathy of Prematurity) study group, laser therapy is the gold standard in the treatment of retinopathy of prematurity. However, progression of the disease is seen in 12% of eyes despite the treatment. Since there is no causal treatment, new therapies of retinopathy of prematurity, are continually sought, such as anti-VEGF agents, beta-blockers, or insulin-like growth factor gene therapy. In cases with concomitant retinal detachment, surgery is performed. The standard therapy for retinopathy of prematurity stages 4-5 involves pars plicata vitrectomy and lensectomy (stage 5), ab externo surgery (scleral buckling) and lens-sparing vitrectomy (some cases of stage 4). Classic vitrectomy with lensectomy is reserved only for cases with advanced retinal tractions, retina-lens apposition or for cases of intraoperative lens damage during the lens-sparing vitrectomy. The ab externo surgery does not eliminate vitreous tractions, but it stabilises the neovascular membrane activity (transforming it into a scar). The indication for this type of operation is stage 4 retinopathy of prematurity with peripheral proliferations, except for the posterior--aggressive form of retinopathy of prematurity. Many papers have been published on combined therapy involving vitrectomy and conservative treatment. In conclusion, optimal timing of surgical intervention is difficult to determine in stages 4 and 5, because the anatomical and functional outcomes in stage 5 are unfavourable. Both, ab externo surgery and vitrectomy tend to produce poor macular vision in eyes with advanced retinopathy of prematurity, therefore surgical intervention at stage 4 just before the local macular retinal detachment provides better anatomical and functional outcomes.

[Elevated level of circulating endothelial cells as an exponent of chronic vascular dysfunction in the course of AMD]. / Wzrost liczby krazacych komórek sródblonka jako wykladnik przewleklej dysfunkcji naczyniowej w AMD.

PURPOSE: In recent years, emerging data support the concept of endothelial dysfunction in the course of age-related macular degeneration (AMD). Circulating endothelial cells (CECs) are desquamated mature cells that have detached from the intimal monolayer in response to endothelial injury. In this study we sought to explore the potential role of endothelial dysfunction in pathogenesis of AMD by measuring the concentration of CECs in peripheral blood of AMD patients. MATERIAL AND METHODS: Peripheral blood samples from 31 patients with diagnosed dry AMD and 46 patients with neovascular AMD were collected. Forty six, age- and sex-matched volunteers without AMD were enrolled as a control group. CECs were counted and analyzed by flow cytometry. RESULTS: Multivariate analyses of patients and controls adjusted for age, gender, presence of ischemic heart disease, hypertension and smoking (current or past) revealed that both wet (beta = +0.45, p = 0.0003) and dry (beta = +0.28, p = 0.027) forms of AMD are independent factors associated with higher number of CECs. CONCLUSIONS: Our results suggest that there is an endothelial alteration accompanying AMD. Increased numbers of CECs AMD patients reflect a severe vascular disturbance and may contribute to the disease process. These findings can help expand our knowledge of the pathogenic mechanisms of AMD and may be relevant to the potential treatment of this disease.

Potential application of adult stem cells in retinal repair--challenge for regenerative medicine.

Stem cells (SCs) maintain the balance among somatic cell populations in various tissues and are responsible for organ regeneration. The remarkable progress of regenerative medicine in the last few years indicates promise for the use of SCs in ophthalmic disorder treatment. This review describes the current view on hierarchy in the SC compartment and presents the latest attempts to use adult SCs in the regeneration of the retina. Research performed primarily in animal models gives hope for using similar strategies in humans. However, the search for the optimal source of SCs for cell therapy continues. We briefly discuss various potential sources of adult SCs that could be employed in regenerative medicine, particularly focusing on recently identified, very small embryonic-like SCs (VSEL-SCs). These cells are even present in the bone marrow and adult tissues of older patients and could be harvested from cord blood. We believe that VSEL-SCs, after the establishment of ex vivo expansion and differentiation protocols, could be harnessed for retina regeneration.

[Neuroprotection in glaucoma]. / Neuroprotekcja w jaskrze.

The aim of this research is to describe one of the most frequent ophthalmology disease-glaucoma and to look at their neurodegenerative nature and methods to stop disease. We use neuroprotection in glaucoma from a short time but despite of ethiological reasons neuroprotection seems to be one of the main mechanism to slow their progression. This research is talking about new opinions about neuroprotection in glaucoma and their epidemiology and etiology.

[Objective retinal nerve fiber laser assessment by scanning laser polarimetry in patients with chiasmal compression]. / Obiektywna ocena zmian warstwy wlókien nerwowych siatkówki za pomoca badania GDx u pacjentów z uciskiem dróg wzrokowych.

PURPOSE: To assess the evaluation ability of retinal nerve fiber layer (RNFL) in patients with visual tracts' compression and to assess the correlation between visual field loss and changes in RNFL. MATERIAL AND METHODS: Polarimetric RNFL analysis (scanning laser polarimeter- NFA/GDx, software version 1.0.16, LDT(inc)) and kinetic perimetry were done in 41 eyes with different types of optic chiasma compression and in 40 healthy eyes, age matched controls. RESULTS: In eyes with optic chiasma compression most of the GDx parameters were statistically different from the control group (P<0.05). In eyes with normal visual fields and with optic chiasma compression most of GDx parameters were statistically different from the other analyzed groups. CONCLUSIONS: GDx may be a helpful tool in diagnosis of optic chiasma diseases. GDx is a useful visual prognostic indicator in the preoperative assessment of optic chiasma compression. Objective RNFL assessment is especially important in patients with serious visual field loss and poor visual acuity.

[Evaluation of retinal nerve fiber thickness with scanning laser polarimetry in patients with anterior ischemic optic neuropathy]. / Ocena grubosci warstwy wlókien nerwowych siatkówki za pomoca skaningowego laserowego polarymetru u pacjentów z przednia niedokrwienna neuropatia nerwu wzrokowego.

PURPOSE: To measure retinal nerve fiber layer thickness (RNFL) in patients with anterior ischemic optic neuropathy (AION) by scanning laser polarimetry and to asses the correlation between RNFL thickness and perimetric indices in AION eyes. MATERIAL AND METHODS: Polarimetric RNFL analysis (scanning laser polarimeter- NFA/GDx, software version 1.0.16, LDTinc) and standard automated perimetry (SAP- HFA, 24-2 thresold test) was done in 28 AION eyes and in 14 healthy age matched controls. RESULTS: In AION eyes most of the GDx parameters were statistically different from the control group (P<0.05). Some of the GDx parameters strongly correlated with SAP indices (MD) in AION eyes. CONCLUSIONS: RNFL thickness measured with NFA/GDx is thinner in AION eyes than in healthy eyes and correlates with visual field loss.

[Retinal nerve fiber layer analysis and evaluation of eye blood flow in patients with glaucoma]. / Ocena grubosci warstwy wlókien nerwowych siatkówki i przeplywu krwi w naczyniach krwionosnych oka u chorych z jaskra.

PURPOSE: The aim of this research was to evaluate the changes of blood flow velocity in ocular arteries (ophthalmic artery, central retinal artery and short posterior ciliary arteries) and the amount of ocular nerve fibers in patients with primary open angle glaucoma (POAG) and normal tension glaucoma (NTG). MATERIAL AND METHOD: The research was done on 17 patients with diagnosed POAG and 13 patients with NTG. No ocular surgery was performed on any of these patients prior to our examinations. The blood flow measurements were made with ACUSON Color Doppler USG 128*P10 type with 7.5 MHz sector phased probe. Parameters of diastolic velocity (Vr), systolic flow velocity (Vs), Golsing pulsation index (PI) and pourcelate resistivity index (RI) were registered, together with the instant spectrography of examined artery. Quantitative retinal nerve fiber layer (RNFL) measurements were obtained by scanning laser polarimetry GDx (software version 1.0.14). RNFL was measured automatically in each of 256x 256 pixels and results were compared to the age-, sex- and race-norms. Approximately 150 wide field of view was used. Average thickness, Superior Maximum, Inferior Maximum, maximum modulation and GDx Number were analysed. All results were compared to age norms. Student's t test was used for statistical analysis. RESULTS: In patients with POAG a statistically significant decrease of Vs in ophthalmic artery was detected in 27% of eyes, in central retinal artery in 51% of eyes and in short posterior ciliary arteries in 45% of eyes. In patients with NTG a statistically significant decrease of Vs was detected in ophthalmic artery in 27% of eyes, in central retinal artery in 65% of eyes and in short posterior ciliary arteries in 53% of eyes. RNFL analysis in eyes with POAG showed a decrease in avg. thickness in 80% of analysed eyes, decrease of Superior Maximum in 84% of analysed eyes, decrease of Inferior Maximum in 77.4% of analysed eyes, decrease in maximal modulation in 87% of analysed eyes and increase of GDx Number in 77% of analysed eyes. RNFL analysis in patients with NTG showed a decrease in av. thickness in 73% of analysed eyes, decrease of Superior Maximum in 80.7% of analysed eyes, decrease of Inferior Maximum in 65.7% of analysed eyes, decrease in maximal modulation in 61.5% of analysed eyes and increase of GDx Number in 57.6% of analysed eyes.