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Öğe Evaluation of the Radiation Dose–Volume Effects of Optic Nerves and Chiasm by Psychophysical, Electrophysiologic Tests, and Optical Coherence Tomography in Nasopharyngeal Carcinoma(SAGE Publications Inc., 2017) Ozkaya Akagunduz O.; Guven Yilmaz S.; Yalman D.; Yuce B.; Demirkilinc Biler E.; Afrashi F.; Esassolak M.Purpose: To evaluate the radiation dose–volume effects of optic nerves and chiasm by visual psychophysical, electrophysiologic tests, and optical coherence tomography in patients with locally advanced nasopharyngeal carcinoma. Materials and Methods: A series of visual tests including visual acuity, visual field, contrast sensitivity, visual evoked potential, and optical coherence tomography were administered to 20 patients with locally advanced (T3-T4) nasopharyngeal carcinoma who were treated with definitive chemoradiotherapy. Volume that received 55 Gy (V55), mean dose (Dmean), highest dose to 5% of the volume (D5), and maximum dose (Dmax) for optic nerves and chiasm were evaluated for each patient. Cutoff values were identified as V55: 50%, Dmean: 50 Gy, D5: 55 Gy, and Dmax: 60 Gy. The effects of radiation dose–volume on ophthalmologic tests were evaluated. Results: Ophthalmological evaluation revealed optic neuropathy with simultaneous retinopathy in 6 eyes of 4 patients and radiation retinopathy alone in both eyes of 1 patient. Regarding radiation dose–volume effects of the optic nerve, significant detrimental effect of all parameters was observed on visual acuity. Visual field and contrast sensitivity were affected significantly with V55 ? 50% and Dmean ? 50 Gy. Visual evoked potential latency was affected significantly with Dmean ? 50 Gy, D5 ? 55 Gy, and Dmax ? 60 Gy. For the chiasm, significant detrimental effect of all parameters was observed on visual acuity as well. Retinal nerve fiber layer thickness and visual evoked potential amplitude were not affected by any of the dose–volume parameters neither optic nerves nor chiasm. Conclusion: The volume receiving the threshold dose, mean dose, and 5% of the volume receiving the maximum dose are important parameters besides maximum dose to optic nerves and chiasm. A comprehensive ophthalmological evaluation including visual field, contrast sensitivity, visual evoked potential latency, and amplitude should be performed for these patients. Visual evoked potential latency is an objective predictor of vision loss before the onset of clinical signs. © The Author(s) 2017.Öğe Functional and morphological assessment of ocular structures and follow-up of patients with early-stage Parkinson’s disease(Springer Netherlands, 2019) Hasanov S.; Demirkilinc Biler E.; Acarer A.; Akkın C.; Colakoglu Z.; Uretmen O.Purpose: To evaluate and follow-up of functional and morphological changes of the optic nerve and ocular structures prospectively in patients with early-stage Parkinson’s disease. Materials and methods: Nineteen patients with a diagnosis of early-stage Parkinson’s disease and 19 age-matched healthy controls were included in the study. All participants were examined minimum three times at the intervals of at least 6 month following initial examination. Pattern visually evoked potentials (VEP), contrast sensitivity assessments at photopic conditions, color vision tests with Ishihara cards and full-field visual field tests were performed in addition to measurement of retinal nerve fiber layer (RNFL) thickness of four quadrants (top, bottom, nasal, temporal), central and mean macular thickness and macular volumes. Results: Best corrected visual acuity was observed significantly lower in study group within all three examinations. Contrast sensitivity values of the patient group were significantly lower in all spatial frequencies. P100 wave latency of VEP was significantly longer, and amplitude was lower in patient group; however, significant deterioration was not observed during the follow-up. Although average peripapillary RNFL thickness was not significant between groups, RNFL thickness in the upper quadrant was thinner in the patient group. While there was no difference in terms of mean macular thickness and total macular volume values between the groups initially, a significant decrease occurred in the patient group during the follow-up. During the initial and follow-up process, a significant deterioration in visual field was observed in the patient group. Conclusion: Structural and functional disorders shown as electro-physiologically and morphologically exist in different parts of visual pathways in early-stage Parkinson’s disease. © 2018, Springer Science+Business Media B.V., part of Springer Nature.Öğe Massive iatrogenic orbital cysts following glaucoma drainage implant and strabismus surgery(BMJ Publishing Group, 2016) Demirkilinc Biler E.; Yagci A.; Uretmen O.; Palamar M.We describe 2 paediatric patients who developed large orbital conjunctival epithelium-lined inclusion cysts postsurgery. Case 1 underwent Ahmed glaucoma valve implant surgery 8 months ago and case 2 underwent strabismus surgery 7 years ago. Both cases had either symptomatic strabismus or a mass causing some degree of proptosis or incomitance due to lesions in the intraorbital space. Following total excision of the cysts all associated symptoms were resolved. Conjunctival cysts following ocular surgery can develop anywhere in the anterior segment; however, large orbital cysts following anterior segment surgery are quite rare. We think that implantation cysts should be considered in the differential diagnosis of patients that have signs of orbital mass with a history of previous anterior segment surgery. Complete excision of the cysts results in resolution of all associated signs and symptoms. © 2016 BMJ Publishing Group Ltd.Öğe Optic disc drusen mimicking papilledema in an infant with Joubert syndrome(Editions Medecine et Hygiene, 2015) Yilmaz S.; Demirkilinc Biler E.; Ece Solmaz A.; Serdaroglu G.; Gazeteci Tekin H.; Gokben S.Optic disc drusen mimicking papilledema in an infant with Joubert syndrome: Joubert Syndrome is a rare autosomal recessive disorder characterized by absence or underdevelopment of the cerebellar vermis. Various ocular and oculomotor findings are frequently seen in cases with Joubert Syndrome. However, only three adolescent patients with Joubert Syndrome were diagnosed with optic disc drusen. Here we present an infant case of Joubert Syndrome referred with papilledema and diagnosed with optic disc drusen.Öğe Strabismus in infants following congenital cataract surgery(Springer Verlag, 2015) Demirkilinc Biler E.; Bozbiyik D.I.; Uretmen O.; Kose S.Purpose: This study aimed to determine the incidence and characteristics of strabismus following congenital cataract surgery in infants. Materials and methods: Patients aged <12 months who underwent surgery for congenital cataract and were followed-up for ?1 years were included. Patients that had strabismus prior to surgery were excluded. Data regarding gender, cataract laterality, morphology, and density, age at the time of cataract surgery, ocular motility post surgery, and the presence of nystagmus were retrospectively obtained from the patients’ records. Results: The study included 79 patients (48 male and 31 female). Unilateral surgery was performed in 14 of the patients, versus bilateral surgery in 65. Strabismus did not occur post surgery in 32 (40.5 %) of the patients (group 1), whereas 47 (59.5 %) (group 2) developed strabismus following surgery. The patients in group 1 were followed-up for a mean 50.7 ± 38.5 months, versus 50.3 ± 39 months in group 2. Mean age at the time of cataract surgery in groups 1 and 2 was 3.6 ± 1.9 years and 4.6 ± 3.2 months respectively. Mean duration of time between cataract surgery and the development of strabismus was 13.3 ± 13 months (range: 1–60 months). Unilateral cases were more prone to develop strabismus, which was statistically significant (p = 0.028). Age at the time of cataract surgery, gender, cataract density, the occurrence of aphakic glaucoma, the presence of nystagmus, and additional ocular surgery were not significantly associated with the development of strabismus. Conclusion: Strabismus develops more frequently in children undergoing cataract surgery. In the present study strabismus occurred in more of the patients that underwent unilateral surgery. Based on the present findings, we think that long-term careful follow-up to monitor the development of strabismus is required in all infants undergoing cataract surgery, especially unilateral cases. © 2015, Springer-Verlag Berlin Heidelberg.
