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Öğe Abnormal Dynamic Pupillometry Relates to Neurologic Disability and Retinal Axonal Loss in Patients With Multiple Sclerosis(Assoc Research Vision Ophthalmology Inc, 2021) Bitirgen, Gulfidan; Akpinar, Zehra; Turk, Huseyin B.; Malik, Rayaz A.Purpose: To assess alterations in quantitative dynamic pupil responses to light in relation to neurologic disability and retinal axonal loss in patients with multiple sclerosis (MS). Methods: Twenty-five patients with relapsing-remitting MS and 25 healthy subjects were included in this cross-sectional study. Pupillary responses were measured with an infrared dynamic pupillometry unit, and peripapillary retinal nerve fiber layer (RNFL) thickness was measured with spectral-domain optical coherence tomography. Neurologic disability was assessed by the Expanded Disability Status Scale (EDSS). Patients with a history of optic neuritis (ON) within 6 months were excluded. Only the right eyes were assessed, except in 11 patients with a history of unilateral ON in whom both eyes were further analyzed to evaluate the effect of previous ON. Results: The initial pupil diameter (P = 0.003) and pupil contraction amplitude (P = 0.027) were lower in patients with MS compared with healthy controls. Initial pupil diameter correlated with EDSS score (? = ?0.458; P = 0.021), and RNFL correlated with contraction latency (? = ?0.524; P = 0.007). There were no significant differences in any of the pupil parameters between eyes with and without a history of ON, and between the ON and fellow eyes of the 11 patients with previous unilateral ON. Conclusions: Dynamic pupillometry reveals significant alterations in pupillary light reflex responses associated with neurologic disability and retinal axonal loss, independent of previous ON. Translational Relevance: Dynamic pupillometry is a simple, noninvasive tool that may be useful in detecting autonomic dysfunction in patients with MS.Öğe Abnormal quantitative pupillary light responses following COVID-19(Springer, 2022) Bitirgen, Gulfidan; Korkmaz, Celalettin; Zamani, Adil; Iyisoy, Mehmet Sinan; Kerimoglu, Hurkan; Malik, Rayaz A.Purpose To characterize alterations in pupillary light reflex responses in subjects following coronavirus disease 2019 (COVID-19), especially those with long-COVID. Methods Thirty-five subjects with previous COVID-19 and 30 healthy control participants were enrolled in this cross-sectional comparative study. An infrared dynamic pupillometry system (MonPack One; Metrovision, France) was used to quantify pupillary light responses. The National Institute for Health and Care Excellence (NICE) long-COVID questionnaire was used to identify persisting symptoms at least 4 weeks after acute COVID-19. Results The median time after the diagnosis of acute COVID-19 was 4.0 (2.0-5.0) months. There was an increase in the latency of pupil contraction (P = 0.001) and a reduction in the duration of pupil contraction (P = 0.039) in post-COVID-19 subjects compared to healthy controls. No significant differences were observed in the initial pupil diameter, amplitude and velocity of pupil contraction or latency, velocity and duration of pupil dilation. Long-COVID was present in 25/35 (71%) subjects and their duration of pupil contraction was reduced compared to subjects without long-COVID (P = 0.009). The NICE long-COVID questionnaire total score (rho = - 0.507; P = 0.002) and neurological score (rho = - 0.412; P = 0.014) correlated with the duration of pupil contraction and the total score correlated with the latency of dilation (rho = - 0.352; P = 0.038). Conclusion Dynamic pupillometry reveals significant alterations in contractile pupillary light responses, indicative of parasympathetic dysfunction after COVID-19.Öğe Altered pupillary light responses are associated with the severity of autonomic symptoms in patients with Fabry disease(Nature Research, 2021) Bitirgen, Gulfidan; Turkmen, Kultigin; Zengin, Nazmi; Malik, Rayaz A.Symptoms of autonomic dysfunction are common in Fabry disease. In this study we aimed to evaluate alterations in the pupillary response to white light stimulation in patients with Fabry disease and their association with the severity of autonomic symptoms. Fourteen consecutive patients with Fabry disease and 14 healthy control participants were enrolled in this cross-sectional study. The Mainz Severity Score Index (MSSI) was used to measure the severity of Fabry disease and the Composite Autonomic Symptom Scale 31 (COMPASS 31) questionnaire was used to evaluate the severity of autonomic symptoms. The pupil light responses were assessed with an infrared dynamic pupillometry unit. There were significant reductions in the amplitude (P=0.048) and duration (P=0.048) of pupil contraction, and the latency of pupil dilation (P=0.048) in patients with Fabry disease compared to control subjects. The total weighted COMPASS 31 score correlated with MSSI (r=0.592; P=0.026) and the duration of pupil dilation (rho =0.561; P=0.037). The pupillomotor weighted sub-score of the COMPASS 31 correlated inversely with the duration of pupil contraction (r=-0.600; P=0.023) and latency of pupil dilation (rho=-0.541; P=0.046), and directly with the duration of pupil dilation (rho =0.877; P<0.001) and MSSI (r=0.533; P=0.049). In conclusion, abnormal pupillary function is demonstrated in patients with Fabry disease, which is associated with the severity of autonomic symptoms.Öğe Analysis of Peripapillary Choroidal Thickness in Unilateral Amblyopia(Lippincott Williams & Wilkins, 2019) Bitirgen, Gulfidan; Mirza, Enver; Ozkagnici, Ahmet; Iyisoy, Mehmet SinanPurpose: To evaluate the peripapillary choroidal thickness (CT) in children with unilateral amblyopia using spectral-domain optical coherence tomography (SD-OCT). Methods: One hundred and six eyes of 53 children with unilateral amblyopia and 20 eyes of 20 children with normal vision were involved in this study. Of the 53 children with unilateral amblyopia, 29 (54.7%) had hyperopic anisometropic amblyopia and 24 (45.3%) had strabismic amblyopia. Peripapillary CT was measured from 6 mm length radial B-scans at the optic nerve head using the enhanced depth imaging program of an SD-OCT (Heidelberg Engineering, Germany). Age, sex, refractive error, and best-corrected visual acuity were also recorded. Results: The average peripapillary CT was greater in amblyopic eyes than in the fellow eyes of the children with amblyopia (P = 0.002), and control eyes (P < 0.001). There was no significant difference between the fellow eyes of children with amblyopia and the control eyes (P = 0.158). The average peripapillary CT was negatively correlated with axial length (AL) in amblyopic eyes (r = -0.381; P = 0.005) and fellow eyes (r = -0.392; P = 0.004) but not in control eyes (r = -0.232; P = 0.325). After adjustment for the possible effects of AL, the average peripapillary CT in amblyopic eyes was still greater than in fellow eyes (P = 0.014) and control eyes (P = 0.022). Conclusion: The peripapillary choroid of eyes with amblyopia was thicker than that of the fellow eyes and control eyes. No significant difference was observed between fellow eyes and control eyes.Öğe Assessment of Corneal Sensation, Innervation and Retinal Nerve Fiber Layer in Patients Treated with Multiple Intravitreal Ranibizumab Injections(Public Library Science, 2017) Bitirgen, Gulfidan; Belviranli, Selman; Malik, Rayaz A.; Kerimoglu, Hurkan; Satirtav, Gunhal; Zengin, NazmiPurpose To evaluate the effects of repeated intravitreal ranibizumab injections on corneal sensitivity, corneal sub-basal nerve plexus (SBNP) and peripapillary retinal nerve fiber layer (RNFL) thickness in patients with neovascular age-related macular degeneration (AMD). Methods Sixty-six eyes of 33 patients who had received unilateral repeated intravitreal ranibizumab injections (0.5 mg/0.05 ml) for the treatment of AMD and 25 eyes of 25 healthy subjects were included in the study. Central corneal sensation was measured using the contact Cochet-Bonnet esthesiometer. The laser scanning in vivo corneal confocal microscope was used to determine corneal SBNP parameters. The peripapillary RNFL thickness was assessed with spectral-domain optical coherence tomography. Data obtained from the ranibizumab-injected eyes were compared with those of the fellow non-treated eyes and the eyes of the healthy control subjects. Results The mean number of ranibizumab injections per eye was 8.9 +/- 5.0 (range 3-20). There were no statistically significant differences in the central corneal sensitivity threshold and corneal SBNP parameters between the ranibizumab-injected eyes and the fellow untreated eyes or between those with neovascular AMD and the healthy control group (P>0.05 for all). The average peripapillary RNFL thickness of the treated eyes did not differ significantly to the fellow eyes (P=0.237), and the eyes of healthy control subjects (P=0.918). There were no significant correlations between the number of ranibizumab injections and any of the study parameters. Conclusions Multiple intravitreal injections of ranibizumab seem to have no harmful effects on corneal sensitivity, innervation and peripapillary RNFL thickness in patients with AMD.Öğe Assessment of Corneal Sensation, Innervation and Retinal Nerve Fiber Layer in Patients Treated with Multiple Intravitreal Ranibizumab Injections(Public Library Science, 2017) Bitirgen, Gulfidan; Belviranli, Selman; Malik, Rayaz A.; Kerimoglu, Hurkan; Satirtav, Gunhal; Zengin, NazmiPurpose To evaluate the effects of repeated intravitreal ranibizumab injections on corneal sensitivity, corneal sub-basal nerve plexus (SBNP) and peripapillary retinal nerve fiber layer (RNFL) thickness in patients with neovascular age-related macular degeneration (AMD). Methods Sixty-six eyes of 33 patients who had received unilateral repeated intravitreal ranibizumab injections (0.5 mg/0.05 ml) for the treatment of AMD and 25 eyes of 25 healthy subjects were included in the study. Central corneal sensation was measured using the contact Cochet-Bonnet esthesiometer. The laser scanning in vivo corneal confocal microscope was used to determine corneal SBNP parameters. The peripapillary RNFL thickness was assessed with spectral-domain optical coherence tomography. Data obtained from the ranibizumab-injected eyes were compared with those of the fellow non-treated eyes and the eyes of the healthy control subjects. Results The mean number of ranibizumab injections per eye was 8.9 +/- 5.0 (range 3-20). There were no statistically significant differences in the central corneal sensitivity threshold and corneal SBNP parameters between the ranibizumab-injected eyes and the fellow untreated eyes or between those with neovascular AMD and the healthy control group (P>0.05 for all). The average peripapillary RNFL thickness of the treated eyes did not differ significantly to the fellow eyes (P=0.237), and the eyes of healthy control subjects (P=0.918). There were no significant correlations between the number of ranibizumab injections and any of the study parameters. Conclusions Multiple intravitreal injections of ranibizumab seem to have no harmful effects on corneal sensitivity, innervation and peripapillary RNFL thickness in patients with AMD.Öğe Assessment of pupillary light reflex using dynamic pupillometry in laser-treated eyes with retinal vein occlusion(Sage Publications Ltd, 2021) Turk, Huseyin Bugra; Bitirgen, Gulfidan; Satirtav, Gunhal; Kerimoglu, HurkanPurpose: This study aims to evaluate the pupillary light reflex measured with dynamic pupillometry in patients who underwent retinal laser photocoagulation due to unilateral retinal vein occlusion (RVO). Methods: A total of 48 patients with unilateral RVO were included in the study. Thirty-four patients had undergone retinal laser photocoagulation while the remaining 14 patients that did not undergo laser treatment were observed for control purposes. Of the laser-treated eyes, 14 eyes (41.2%) had central RVO (CRVO) and 20 eyes (58.8%) had branch RVO (BRVO). Among the 14 patients with RVO without laser treatment, nine eyes (64.3%) had CRVO and five eyes (35.7%) had BRVO. Pupillary light reflexes were assessed with dynamic pupillometry (MonPackOne (R); Metrovision, France). The parameters of the eyes with RVO were compared with that of fellow healthy eyes. Results: Mean patient age was 65.8 +/- 10.4 years and median time after photocoagulation was 25.5 months. Eyes that received laser photocoagulation had lower pupil contraction amplitude (p = 0.037), prolonged contraction latency (p = 0.027), slower contraction velocity (p = 0.043), and slower dilation velocity (p < 0.001) compared to healthy fellow eyes. Subgroup analysis revealed that eyes with CRVO had lower contraction amplitude (p = 0.013) and slower dilation velocity (p = 0.003), and eyes with BRVO had slower dilation velocity (p = 0.003). Non-laser-treated eyes with RVO revealed no significant difference in any of the pupillary light reflex parameters compared to fellow eyes. Conclusion: Laser-treated eyes with RVO demonstrated changes in pupillary light reflex parameters including reduced contraction amplitude, prolonged contraction latency, and slower contraction and dilation velocities measured with dynamic pupillometry.Öğe Characteristics of the cornea in patients with pseudoexfoliation syndrome(Consel Brasil Oftalmologia, 2015) Oltulu, Refik; Satirtav, Gunhal; Kayitmazbatir, Emine Tinkir; Bitirgen, Gulfidan; Ozkagnici, Ahmet; Karaibrahimoglu, AdnanPurpose: To quantify the morphological alterations in corneal nerve fibers and cells in patients with pseudoexfoliation syndrome (PEX) and their relationship with the presence of hyperreflective endothelial deposits observed using in vivo confocal microscopy. Methods: One eye each of 37 patients with PEX and 20 age-matched healthy control subjects was evaluated by in vivo corneal confocal microscopy. Patients with PEX were further classified into two groups: those with and without hyperreflective endothelial deposits. We evaluated the densities of basal epithelial cells, anterior and posterior stromal keratocytes, and endothelial cells and structure of sub-basal nerve fibers. Results: The mean anterior and posterior stromal keratocyte and endothelial cell densities and corneal sub-basal nerve plexus variables were significantly lower in patients with PEX compared with those in healthy control subjects. The mean basal epithelial cell density did not significantly differ. Conclusion: Eyes with PEX presented decreased corneal sub-basal nerve plexus variables and cell densities in all corneas, except for the mean basal epithelial cell density. Further, a trend of lower corneal sub-basal nerve plexus measurements in patients with hyperreflective endothelial deposits compared with those without endothelial deposits was observed.Öğe Corneal axonal loss as an imaging biomarker of neurodegeneration in multiple sclerosis: a longitudinal study(Sage Publications Ltd, 2023) Petropoulos, Ioannis N.; Al-Shibani, Fatima; Bitirgen, Gulfidan; Ponirakis, Georgios; Khan, Adnan; Gad, Hoda; Mahfoud, Ziyad R.Background:Resourceful endpoints of axonal loss are needed to predict the course of multiple sclerosis (MS). Corneal confocal microscopy (CCM) can detect axonal loss in patients with clinically isolated syndrome and established MS, which relates to neurological disability. Objective:To assess corneal axonal loss over time in relation to retinal atrophy, and neurological and radiological abnormalities in MS. Methods:Patients with relapsing-remitting (RRMS) (n = 68) or secondary progressive MS (SPMS) (n = 15) underwent CCM and optical coherence tomography. Corneal nerve fibre density (CNFD-fibres/mm(2)), corneal nerve branch density (CNBD-branches/mm(2)), corneal nerve fibre length (CNFL-mm/mm(2)) and retinal nerve fibre layer (RNFL-mu m) thickness were quantified along with neurological and radiological assessments at baseline and after 2 years of follow-up. Age-matched, healthy controls (n = 20) were also assessed. Results:In patients with RRMS compared with controls at baseline, CNFD (p = 0.004) and RNFL thickness (p < 0.001) were lower, and CNBD (p = 0.003) was higher. In patients with SPMS compared with controls, CNFD (p < 0.001), CNFL (p = 0.04) and RNFL thickness (p < 0.001) were lower. For identifying RRMS, CNBD had the highest area under the receiver operating characteristic (AUROC) curve (0.99); and for SPMS, CNFD had the highest AUROC (0.95). At follow-up, there was a further significant decrease in CNFD (p = 0.04), CNBD (p = 0.001), CNFL (p = 0.008) and RNFL (p = 0.002) in RRMS; in CNFD (p = 0.04) and CNBD (p = 0.002) in SPMS; and in CNBD (p = 0.01) in SPMS compared with RRMS. Follow-up corneal nerve loss was greater in patients with new enhancing lesions and optic neuritis history. Conclusion:Progressive corneal and retinal axonal loss was identified in patients with MS, especially those with more active disease. CCM may serve as an imaging biomarker of axonal loss in MS.Öğe Corneal confocal microscopy detects corneal nerve damage and increased dendritic cells in Fabry disease(Nature Publishing Group, 2018) Bitirgen, Gulfidan; Turkmen, Kultigin; Malik, Rayaz A.; Ozkagnici, Ahmet; Zengin, NazmiFabry disease is characterised by neuropathic pain and accelerated vascular disease. This study evaluates the utility of corneal confocal microscopy (CCM) to non-invasively quantify corneal nerve and endothelial cell morphology and dendritic cell (DC) density in relation to disease severity in subjects with Fabry disease. Seventeen consecutive participants with Fabry disease and 17 healthy control subjects were included in this cross-sectional study. Fabry disease severity was measured using the Mainz Severity Score Index (MSSI). Central corneal sensitivity was assessed with a contact corneal esthesiometer. There was a significant reduction in the corneal sensitivity (5.75 [5.25-6.00] vs. 6.00 [6.00-6.00] cm, P = 0.014), nerve fiber density (NFD) (26.4 +/- 10.1 vs. 33.7 +/- 7.9 fibers/mm(2), P = 0.025) and nerve fiber length (NFL) (15.9 +/- 3.4 vs. 19.5 +/- 4.4 mm/mm(2), P = 0.012) and an increase in DC density (38.3 [17.5-97.3] vs. 13.5 [0-29.4] cells/mm(2), P = 0.004) in subjects with Fabry disease compared to the healthy control subjects. The total MSSI score correlated with NFD (rho = -0.686; P = 0.006), NFL (rho = -0.692; P = 0.006), endothelial cell density (rho = -0.511; P = 0.036), endothelial cell area (rho = 0.514; P = 0.036) and alpha-galactosidase A enzyme activity (rho = -0.723; P = 0.008). This study demonstrates reduced corneal sensitivity, corneal nerve fiber damage and increased DCs in subjects with Fabry disease.Öğe Corneal confocal microscopy identifies corneal nerve fibre loss and increased dendritic cells in patients with long COVID(Bmj Publishing Group, 2022) Bitirgen, Gulfidan; Korkmaz, Celalettin; Zamani, Adil; Ozkagnici, Ahmet; Zengin, Nazmi; Ponirakis, Georgios; Malik, Rayaz A.Background/Aims Long COVID is characterised by a range of potentially debilitating symptoms which develop in at least 10% of people who have recovered from acute SARS-CoV-2 infection. This study has quantified corneal sub-basal nerve plexus morphology and dendritic cell (DC) density in patients with and without long COVID. Methods Forty subjects who had recovered from COVID-19 and 30 control participants were included in this cross-sectional comparative study undertaken at a university hospital. All patients underwent assessment with the National Institute for Health and Care Excellence (NICE) long COVID, Douleur Neuropathique 4 (DN4) and Fibromyalgia questionnaires, and corneal confocal microscopy (CCM) to quantify corneal nerve fibre density (CNFD), corneal nerve branch density (CNBD), corneal nerve fibre length (CNFL), and total, mature and immature DC density. Results The mean time after the diagnosis of COVID-19 was 3.7 +/- 1.5 months. Patients with neurological symptoms 4 weeks after acute COVID-19 had a lower CNFD (p=0.032), CNBD (p=0.020), and CNFL (p=0.012), and increased DC density (p=0.046) compared with controls, while patients without neurological symptoms had comparable corneal nerve parameters, but increased DC density (p=0.003). There were significant correlations between the total score on the NICE long COVID questionnaire at 4 and 12 weeks with CNFD (rho=-0.436; p=0.005, rho=-0.387; p=0.038, respectively) and CNFL (rho=-0.404; p=0.010, rho=-0.412; p=0.026, respectively). Conclusion Corneal confocal microscopy identifies corneal small nerve fibre loss and increased DCs in patients with long COVID, especially those with neurological symptoms. CCM could be used to objectively identify patients with long COVID.Öğe Corneal Confocal Microscopy to Image Small Nerve Fiber Degeneration: Ophthalmology Meets Neurology(Frontiers Media Sa, 2021) Petropoulos, Ioannis N.; Bitirgen, Gulfidan; Ferdousi, Maryam; Kalteniece, Alise; Azmi, Shazli; D'Onofrio, Luca; Lim, Sze HwayNeuropathic pain has multiple etiologies, but a major feature is small fiber dysfunction or damage. Corneal confocal microscopy (CCM) is a rapid non-invasive ophthalmic imaging technique that can image small nerve fibers in the cornea and has been utilized to show small nerve fiber loss in patients with diabetic and other neuropathies. CCM has comparable diagnostic utility to intraepidermal nerve fiber density for diabetic neuropathy, fibromyalgia and amyloid neuropathy and predicts the development of diabetic neuropathy. Moreover, in clinical intervention trials of patients with diabetic and sarcoid neuropathy, corneal nerve regeneration occurs early and precedes an improvement in symptoms and neurophysiology. Corneal nerve fiber loss also occurs and is associated with disease progression in multiple sclerosis, Parkinson's disease and dementia. We conclude that corneal confocal microscopy has good diagnostic and prognostic capability and fulfills the FDA criteria as a surrogate end point for clinical trials in peripheral and central neurodegenerative diseases.Öğe Corneal nerve loss and increased Langerhans cells are associated with disease severity in patients with rheumatoid arthritis(Springernature, 2023) Bitirgen, Gulfidan; Kucuk, Adem; Ergun, Mustafa Cagri; Satirtav, Gunhal; Malik, Rayaz A.Background/ObjectivesRheumatoid arthritis (RA) is a multisystem autoimmune disorder characterized by articular and extra-articular manifestations. Neuropathy is a poorly studied manifestation of RA. The aim of this study was to utilize the rapid non-invasive ophthalmic imaging technique of corneal confocal microscopy to identify whether there is evidence of small nerve fibre injury and immune cell activation in patients with RA.Subjects/MethodsFifty consecutive patients with RA and 35 healthy control participants were enrolled in this single-centre, cross-sectional study conducted at a university hospital. Disease activity was assessed with the 28-Joint Disease Activity Score and erythrocyte sedimentation rate (DAS28-ESR). Central corneal sensitivity was measured with a Cochet-Bonnet contact corneal esthesiometer. A laser scanning in vivo corneal confocal microscope was used to quantify corneal nerve fibre density (CNFD), nerve branch density (CNBD), nerve fibre length (CNFL), and Langerhans cell (LC) density.ResultsCorneal sensitivity (P = 0.01), CNFD (P = 0.02), CNBD (P < 0.001), and CNFL (P < 0.001) were lower, and mature (P = 0.001) and immature LC densities (P = 0.011) were higher in patients with RA compared to control subjects. CNFD (P = 0.016) and CNFL (P = 0.028) were significantly lower in patients with moderate to high (DAS28-ESR > 3.2) compared to mild (DAS28-ESR <= 3.2) disease activity. Furthermore, the DAS28-ESR score correlated with CNFD (r = -0.425; P = 0.002), CNBD (rho = -0.362; P = 0.010), CNFL (r = -0.464; P = 0.001), total LC density (rho = 0.362; P = 0.010) and immature LC density (rho = 0.343; P = 0.015).ConclusionsThis study demonstrates reduced corneal sensitivity, corneal nerve fibre loss and increased LCs which were associated with the severity of disease activity in patients with RA.Öğe Coronavirus Disease 2019-Related Fulminant Idiopathic Intracranial Hypertension(Georg Thieme Verlag Kg, 2023) Caliskan, Burcu; Canbal, Abdullah; Guven, Ahmet Sami; Bitirgen, Gulfidan; Erdi, Mehmet Fatih; Caksen, HuseyinIdiopathic intracranial hypertension or pseudotumor cerebri syndrome (PTCS) is defined as an increase in intracranial pressure (ICP) without an identifiable and/or structural cause or abnormal cerebrospinal fluid content. The most common symptoms of PTCS include headache, vomiting, pulsatile tinnitus, blurred vision, and diplopia. In 2 to 3% of PTCS patients, severe and rapidly progressive vision loss may develop within 1 month since symptoms begin; this clinical condition is usually defined as fulminant idiopathic intracranial hypertension (FIIH). This study presented a patient admitted to the hospital with headache and blurred vision, who also had high severe acute respiratory syndrome coronavirus 2 infections total antibody level and was treated with a lumboperitoneal shunt due to medical treatment-resistant increased ICP. We also reviewed similar cases previously reported in the literature. To the best of our knowledge, no children affected with coronavirus 2019 related to FIIH and requiring surgical treatment have been yet reported in the literature.Öğe Effect of mydriasis induced by topical 0.5% tropicamide instillation on the corneal biomechanical properties in healthy individuals measured by ocular response analyzer(Taylor & Francis Ltd, 2015) Oltulu, Refik; Satirtav, Gunhal; Altunkaya, Orhan; Bitirgen, Gulfidan; Okka, MehmetPurpose: This observational study aims to investigate the effects of tropicamide (0.5%) on corneal biomechanical properties, with the ocular response analyzer (ORA), in healthy individuals. Methods: Corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg), and corneal-compensated intraocular pressure (IOPcc) measurements of 38 (21 female and 17 male) healthy individuals, before and after 30 min of 0.5% tropicamide instillation, were performed by using the ORA. Results: The mean CH, CRF, IOPg and IOPcc measurements of the eyes were 10.2 +/- 1.9 mmHg, 10.3 +/- 2.1 mmHg, 15.7 +/- 3.4 mmHg, 16.4 +/- 3.3 mmHg pre-tropicamide, and 10.4 +/- 1.7 mmHg, 10.3 +/- 2.1 mmHg, 15.3 +/- 3.4 mmHg, 15.8 +/- 2.7 mmHg post-tropicamide, respectively. The differences between the pre- and post-tropicamide measurements of the eyes were insignificant (p = 0.184, p = 0.659, p = 0.294, p = 0.150, respectively; paired t-test). Conclusions: A tropicamide instillation does not lead to significant changes in the corneal biomechanical properties. Therefore, it can be used safely in disease, i.e. in the diagnosis and follow-up ORA as it does not cause any change.Öğe Effects of panretinal laser photocoagulation on the corneal nerve plexus and retinal nerve fiber layer in retinal vein occlusion(Wichtig Publishing, 2017) Bitirgen, Gulfidan; Belviranli, Selman; Malik, Rayaz A.; Kerimoglu, Hurkan; Ozkagnici, AhmetPurpose: To determine the effects of panretinal photocoagulation (PRP) on corneal sub-basal nerve plexus (SBNP) and peripapillary retinal nerve fiber layer (RNFL) thickness in patients with unilateral central retinal vein occlusion (CRVO) who had previously undergone PRP treatment. Methods: Sixty-four eyes of 32 patients (19 male, 13 female) with unilateral ischemic type CRVO who had undergone PRP treatment at least 6 months previously were included in this cross-sectional study. The laser scanning in vivo corneal confocal microscope was used to determine corneal SBNP parameters. The peripapillary RNFL thickness was assessed with spectral-domain optical coherence tomography. Data obtained from the PRP-treated eyes were compared with those of the fellow unaffected eyes. Results: The mean age of patients was 63.5 +/- 10.7 years (range 45-85 years). The mean nerve fiber density (NFD), nerve branch density, and nerve fiber length (NFL) were significantly lower in PRP-treated eyes compared with fellow eyes (p<0.001 for all). Average peripapillary RNFL thickness was significantly lower in PRP-treated eyes than in fellow eyes (p = 0.007). The NFD and NFL showed a modest but significant positive correlation with average peripapillary RNFL thickness (r = 0.310, p = 0.013 and r = 0.272, p = 0.030, respectively). conclusions: Significant reductions in corneal SBNP parameters and average peripapillary RNFL thickness were observed in the eyes of patients receiving PRP for the treatment of ischemic CRVO.Öğe Evaluation of Contact Lens-Induced Changes in Keratoconic Corneas Using In Vivo Confocal Microscopy(Assoc Research Vision Ophthalmology Inc, 2013) Bitirgen, Gulfidan; Ozkagnici, Ahmet; Malik, Rayaz A.; Oltulu, RefikPURPOSE. To quantitatively analyze laser scanning in vivo confocal microscopy (IVCM) images of all corneal layers in contact lens-wearing and noncontact lens-wearing keratoconus patients. METHODS. The study population included rigid gas permeable (RGP) contact lens-wearing keratoconus patients (group 1; N = 29), keratoconus patients who did not wear contact lenses (group 2; N = 30), and subjects who neither had keratoconus nor wore contact lenses (group 3; N = 30), with groups 2 and 3 matched to group 1 by age and sex. The central cornea was examined with IVCM in all subjects. The mean duration of contact lens wear was 5.50 +/- 3.68 years (range, 2-15 years). RESULTS. Eyes with keratoconus showed significantly lower basal epithelial cell and anterior and posterior stromal keratocyte densities, as well as subbasal nerve fiber density, nerve branch density, and nerve fiber length compared with healthy control subjects. Furthermore, compared with group 2, group 1 had significantly lower basal epithelial cell density (4920 +/- 476 cells/mm(2) vs. 4503 +/- 461 cells/mm(2), P = 0.001) and anterior stromal keratocyte density (561 6 91 cells/mm2 vs. 464 6 55 cells/mm2, P < 0.001), but there was no significant difference for posterior stromal keratocyte density (P = 0.808), endothelial cell density (P = 0.699), or subbasal nerve fiber density (P = 0.142), nerve branch density (P = 0.614), and nerve fiber length (P = 0.850). CONCLUSIONS. Significant corneal microstructural abnormalities were observed in eyes with keratoconus. RGP contact lens wear was associated with a further reduction in the basal epithelial cell and anterior stromal keratocyte densities, but with no effect on posterior stromal keratocyte density, endothelial cell density, or corneal nerve morphology.Öğe Evaluation of Pupillary Light Reflex in Amblyopic Eyes Using Dynamic Pupillometry(Turkish Ophthalmological Soc, 2019) Bitirgen, Gulfidan; Daraghma, Mohammed; Ozkagnici, AhmetObjectives: To evaluate the pupillary light reflex responses in patients with unilateral strabismic and anisometropic amblyopia using dynamic pupillometry. Materials and Methods: A total of 102 eyes of 51 patients with unilateral amblyopia were included in this cross-sectional study. Of the 51 patients, 37 (72.5%) had strabismic amblyopia and 14 (27.5%) had anisometropic amblyopia. All patients underwent complete ophthalmological examination, and pupillary light reflex responses were measured using a computerized dynamic pupillometry system (MonPack One; Metrovision, France). Initial pupil diameter; the amplitude, latency, duration, and velocity of pupil contraction; and the latency, duration, and velocity of pupil dilation were recorded. Results obtained from the patients' amblyopic and normal fellow eyes were compared using paired-samples t-test and Wilcoxon signed rank test. Results: The mean age of the patients was 11.9 +/- 6.0 years. Amblyopic eyes had longer contraction latency (p=0.009), shorter contraction duration (p=0.002), and higher dilation velocity (p=0.033) compared to fellow eyes, while other parameters did not show significant differences. In subgroup analysis, eyes with strabismic amblyopia had longer contraction latency (p=0.006) and shorter contraction duration (p=0.017), while eyes with anisometropic amblyopia had shorter contraction duration (p=0.030) when compared with fellow eyes. Conclusion: In this study, the objective records obtained by dynamic pupillometry showed that pupillary light reflex responses are affected in amblyopic eyes. This finding may shed light on unclear aspects of the pathophysiology of amblyopia.Öğe GAPO syndrome: Four new patients with congenital glaucoma and myelinated retinal nerve fiber layer(Wiley, 2013) Bozkurt, Banu; Yildirim, Mahmut Selman; Okka, Mehmet; Bitirgen, GulfidanThis article reports on the ophthalmological features of four Turkish children with GAPO syndrome, a very rare autosomal recessive condition characterized by growth retardation (G), alopecia (A), pseudoanodontia (P) (failure of tooth eruption), and optic atrophy (O). The children were from two unrelated families born to consanguineous parents. They had the characteristic facial appearance of alopecia, rarefaction of eyebrows and eyelashes, frontal bossing, high forehead, midfacial hypoplasia, hypertelorism, and thickened eyelids and lips. Two children had severe end-stage glaucoma in both eyes and unilateral corneal opacity, whereas other two children had myelinated retinal nerve fiber layer; one with bilateral optic atrophy and the other one with persistent pupillary membrane in the left eye. (c) 2013 Wiley Periodicals, Inc.Öğe Iatrogenic Lens Injuries(Turkish Ophthalmological Soc, 2012) Kamis, Umit; Bitirgen, GulfidanDuring intraocular surgery, undesired damages of various etiology may occur in adjacent tissues. One of these tissues is the crystalline lens, which may be traumatized both in anterior segment and posterior segment surgeries, and when damaged, it usually causes marked decrease in visual acuity. The leading causes of iatrogenic lens injuries are intravitreal injection, laser iridotomy, phakic intraocular lens implantation, anterior chamber paracentesis, and vitreoretinal surgery. When crystalline lens damage occurs, its negative effect on visual function may be eliminated by performing cataract surgery intraoperatively or in elective conditions.
