Browsing by Author "Toprak A.B."

Now showing 1 - 8 of 8
  • No Thumbnail Available
    Item
    Relation of optic disc topography and age to thickness of retinal nerve fibre layer as measured using scanning laser polarimetry, in normal subjects
    (2000) Toprak A.B.; Yilmaz Ö.F.
    Aims - To evaluate the relation of the optic nerve head topographic measurements and age with the thickness of the retinal nerve fibre layer (RNFL) in normal Caucasoid subjects by means of scanning laser polarimetry and tomography. Methods - Topographic optic disc measurements and RNFL thickness values of 38 normal Caucasoid subjects of both sexes aged 20 to 78 were measured using a confocal scanning laser ophthalmoscope and a confocal scanning laser polarimeter. One eye was randomly selected for statistical analysis. The effects of optic disc size, age, and optic disc head topographic measurements of total and regional RNFL thickness were evaluated. Results - Age showed a significant correlation with the integral of the total RNFL thickness (R = -0.341, p < 0.05). The optic disc size showed a significant correlation with the integral of the total, superior, and inferior quadrant RNFL thickness (R = 0.425, p < 0.01), (R = 0.361, p < 0.05), (R = 0.468, p < 0.05). Neuroretinal rim area (NRA) had a correlation with the superior and inferior quadrant RNFL thickness values (R = 0.339, p < 0.05) (R = 0.393, p < 0.05). There was no significant correlation between the other optic disc topographic measurements and RNFL thickness values (p > 0.05). Conclusion - The thickness of total as well as superior and inferior quadrant peripapillary RNFL as measured by scanning laser polarimetry increased significantly with an increase in optic disc size. The cross sectional area occupied by superior and inferior polar RNFL increased significantly with an increase in NRA. The total cross sectional area occupied by RNFL decreased significantly with an increase in age. The effects of optic disc size, age, and NRA should be considered when the peripapillary RNFL thickness is evaluated.
  • No Thumbnail Available
    Item
    Fluorescein dye disappearance test in patients with different degrees of epiphora
    (Wichtig Editore s.r.l., 2002) Toprak A.B.; Erkin E.F.; Kayikçioǧlu Ö.; Seymenoǧlu G.; Güler C.; Unlu H.H.
    PURPOSE. To assess the diagnostic efficacy of a modification of the fluorescein dye disappearance test (DDT) in patients with different degrees of epiphora. METHODS. DDT was performed by instilling a drop of 2% fluorescein in the eye. Schirmer tear test strips were placed in the lower conjunctival fornix, after 3 and 10 minutes. The colour dilution on the strips was compared to a scale with known standards and the most closely comparable colour dilution was chosen and recorded as the visual scale test (VST) grade of the strip. The grey-scale value (GV) of each strip was calculated by computer image analysis. The control group comprised 44 patients, mean age 44.8 years (SD 7.5, range 30-60). There were 13 patients in group 1 with moderate epiphora; mean age was 44.2 years (SD 9.5, range 30-60). There were 17 patients in group 2 with severe epiphora; mean age was 48.3 years (SD 7.7, range 37- 60). RESULTS. VST and GV differed significantly between controls and group 1 patients at 3 minutes (p=0.002, p=0.001), and between controls and group 2 patients at 3 minutes (p<0.001, p<0.001). There was no difference between groups 1 and 2 patients in VST and GV at 3 minutes. The differences were highly significant between controls and group 1 at 10 minutes (p=0.001, p=0.007), and between controls and group 2 at 10 minutes (p<0.001, p<0.001). The differences in GV and VST between groups 1 and 2 were significant at 10 minutes (p=0.026, p=0.018). CONCLUSIONS. This modified DDT permits identification of different degrees of epiphora in a non-invasive manner, it can therefore be used to evaluate the outcome of different treatment strategies.
  • No Thumbnail Available
    Item
    A histological analysis of the protective effect of ischemic preconditioning in the rat retina
    (2002) Toprak A.B.; Ozbilgin K.; Toprak V.; Tuglu I.; Guler C.
    Purpose. Ischemic preconditioning (IP) protects the retina from the damaging effect of subsequent ischemia in vivo. We aimed to investigate the histological alterations induced by the protective effect of IP to the retina. Methods. The eyes of the rats were rendered ischemic by intra-ocular pressure (IOP) elevation. IP procedure consisted of producing ischemia for 5 minutes. Sham operation was similar to IP procedure except the pressure elevation. The operational eyes of sham and IP group underwent 60 minutes of ischemia 24 hours after the first procedure. The eyes contralateral to the experimental eyes made up the control group. The eyes were histologically analysed one week after the ischemia. Results. The total retinal thickness of the sham group was significantly less than total retinal thickness of the control group (p < 0.001). There was not a significant difference between control and IP group regarding the total retinal thickness (p > 0.05). The thickness of the inner retinal layers of the sham group were significantly less than corresponding retinal layers of the control group (p < 0.001). The inner plexiform layer (IPL) and inner nuclear layer (INL) thickness values of the sham group were significantly less than same layers of the IP group (p < 0.001). Ganglion cell layer (GCL) thickness of the IP group was significantly less than GCL thickness of the control group (p < 0.001). IPL thickness of the IP group was significantly less than that of control group's (p < 0.05). The GCL and total retinal thickness of the IP group were significantly more than thickness of the corresponding layers of the sham group (p < 0.05). Conclusion. IP considerably protects inner retinal layers from subsequent ischemic damage in a high IOP ischemic model. This endogenous process could further be utilized to tailor specific neuroprotective strategies for retinal cells.
  • No Thumbnail Available
    Item
    Trypan blue staining of the anterior capsule under an air bubble with a modified cannula
    (Slack Incorporated, 2003) Toprak A.B.; Erkin E.F.; Guler C.
    To attain good visibility of the anterior capsule in the advanced or white cataract, trypan blue 0.1% is used to stain the anterior capsule. The dye is usually injected under an air bubble. However, it is difficult to inject the dye properly due to capillary forces. An ordinary anterior chamber cannula was modified and its coverage area increased to facilitate the staining of the anterior capsule under an air bubble. The anterior capsule was stained properly by using the modified cannula in all of the cases.
  • No Thumbnail Available
    Item
    Tear function changes of postmenopausal women in response to hormone replacement therapy
    (2003) Kuscu N.K.; Toprak A.B.; Vatansever S.; Koyuncu F.M.; Guler C.
    Objective: The goal of this study was to search the effect of hormone replacement therapy (HRT) on tear function changes in postmenopausal women. Methods: Following initial ophtalmic evaluation and tear sample collection, the subjects were given daily 0.625 mg conjugated estrogen, and either continuous combined or cyclic 5 mg medroxyprogesterone acetate was added. Eye examination included visual acuity, slit-lamp examination, fundus examination, tonometry, Schirmer's test, and break up time (BUT) evaluation. Six months later, control examination was done and repeat tear samples were obtained. Tear immune globulin A (IgA) and lysozyme levels were measured by gel electrophoresis. The pictures of the bands were evaluated by digital image analysis with Scion Image program. Results: Conjunctival vascular congestion, laxity and corneal desquamation did not change before and after HRT (P>0.05). A significant improvement was noted in meibomian gland inflammation (P=0.034). We have not observed any significant difference in burning, foreign body sensation, and tearing (P>0.05). In addition, no significant difference was noted in BUT (P=0.370) and Schirmer's test values (P=0.271). Though both lysozyme and IgA levels were elevated following the therapy, only IgA levels increased significantly (P=0.04). Conclusion: HRT decreased meibomian gland inflammation and increased tear lysozyme and IgA levels in postmenopausal women. © 2002 Elsevier Science Ireland Ltd. All rights reserved.
  • No Thumbnail Available
    Item
    Cross-validation of the Turkish version of the 25-item National Eye Institute Visual Functioning Questionnaire (NEI-VFQ 25)
    (2005) Toprak A.B.; Eser E.; Guler C.; Baser F.E.; Mayali H.
    Purpose: To test the validity and reliability of the Turkish version of the self-administered form of the National Eye Institute Visual Functioning Questionnaire (NEI-VFQ 25). Methods: Patients with no limitations to respond to a health status interview and affected by a chronic eye disease were enrolled. The Turkish versions of the abbreviated form of World Health Organization Quality of Life (WHOQOL-BREF) and the NEI-VFQ 25 instruments were administered to all participants. Results: The mean (SD) age of the participants was 60.9 (14.5) years. There were 61 patients with one of the following conditions: Cataract (57.4%), diabetic retinopathy (13.2%), age related macular degeneration (ARMD) (11.4%), glaucoma (9.8%) and degenerative myopia (8.2%). The Cronbach alpha of the overall scale was 0.97; the Cronbach alpha ranged from 0.94 to 0.78 for the subscales. The physical, psychological, environmental and social domains of the WHOQOL-BREF had fair to good correlations with the NEI-VFO 25 (r = 0.68 to r = 0.26), which indicated a sufficient convergent validity. Patients with lower visual acuity (VA) had lower index scores than those with higher VA (p = 0.001), which showed a sufficient responsiveness. Conclusion: Statistical analysis showed that Turkish version of the NEI-VFQ is a valid and reliable instrument to measure vision-related quality of life in patients with chronic eye diseases. Copyright © Taylor & Francis Inc.
  • No Thumbnail Available
    Item
    Computer assisted image analysis of peroxidase stained endometrial tissue
    (2006) Toprak A.B.; Vatansever S.; Özbilgin K.
    Aim: In immunohistochemistry, antibodies are used to detect and localize antigens in cellular compartments in sections taken from frozen or paraffin blocks. Currently, computerized image processing techniques are widely available to analyze immunohistochemically stained tissues; however, the image analysis programs are generally highly specific and expensive. We aimed to show the feasibility of computer assisted image analysis (CAIA) by using two computer programs currently in widespread use. Methods: Two available computer programs, Adobe Photoshop CS and ImageJ, were used to separate areas in the same tissue sections stained with NOS antibody and labeled with peroxidase in human endometrial tissue. CAIA was made on the relevant images using these two programs. Results: There was a significant difference among the groups according to staining intensity, in all three grades of staining (P < 0.001, P < 0.05, and P < 0.001, respectively). Subjective assessment of the images was in good agreement with objective CAIA. One (+) positive stained area was greater in group 1 and less in group 2 and group 3 (P < 0.001 and P < 0.001, respectively). Group 3, which was considered as the most intensely stained by the observer, had the greatest amount of ++ staining. Conclusion: CAIA is a safe and reliable method of analyzing tissue samples stained using immunohistochemical methods. © TÜBİTAK.
  • No Thumbnail Available
    Item
    MRI findings of globe and optic nerves in tilted disk syndrome
    (Centauro SRL, 2007) Orguc S.; Toprak A.B.; Demiray B.; Tarhan S.; Güler C.
    We assessed the anatomical variations of the globe and optic nerve in tilted disk (TD) syndrome using magnetic resonance imaging (MRI) findings and compared them with a control group. Eleven patients diagnosed with TD syndrome during eye examination were referred for MRI of the sella and chiasm to exclude intracranial mass lesions. The shape of the globe, the chiasmal angle, the insertion angles of the optic nerve in axial and parasagittal planes determined by lines parallel to the optic nerve and tangent to the globe in TD syndrome were compared with a control group consisting of 53 cases. Gender ratios were 7/4 (F/M) for the TD group and 35/18 for the control group (p>0.05). The insertion angle of the optic disk to the globe was wider in the temporal quadrant (p<0.05) and narrower in the nasal quadrant (p<0.05) in TD syndrome than in the control group. There was no significant difference in the superior and inferior insertion angles between the groups. The anterior-posterior (AP) diameter of the globe was significantly longer in patients with TD (p<0.05). There was no significant difference between the optic chiasm angles. The relationships of the optic disk and the globe were significantly different in patients with TD syndrome in comparison to the control group. TD syndrome is related to the malalignment of optic nerve and globe in the horizontal plane.