Levent Tok

Effects of melatonin on Wi-Fi-induced oxidative stress in lens of rats

Introduction: Melatonin has been considered a potent antioxidant that detoxifies a variety of reactive oxygen species in many pathophysiological states of eye. The present study was designed to determine the effects of Wi-Fi exposure on the lens oxidant, antioxidant redox systems, as well as the possible protective effects of melatonin on the lens injury induced by electromagnetic radiation (EMR). Materials and Methods: Thirty-two rats were used in the current study and they were randomly divided into four equal groups as follows: First and second groups were cage-control and sham-control rats. Rats in third group were exposed to Wi-Fi (2.45 GHz) for duration of 60 min/day for 30 days. As in the third group, the fourth group was treated with melatonin. The one-hour exposure to irradiation in second, third and fourth took place at noon each day. Results: Lipid peroxidation levels in the lens were slightly higher in third (Wi-Fi) group than in cage and sham control groups although their concentrations were significantly (P < 0.05) decreased by melatonin supplementation. Glutathione peroxidase (GSH-Px) activity was significantly (P < 0.05) lower in Wi-Fi group than in cage and sham control groups although GSH-Px (P < 0.01) and reduced glutathione (P < 0.05) values were significantly higher in Wi-Fi + melatonin group than in Wi-Fi group. Conclusions: There are poor oxidative toxic effects of one hour of Wi-Fi exposure on the lens in the animals. However, melatonin supplementation in the lens seems to have protective effects on the oxidant system by modulation of GSH-Px activity.

Elevated hydrostatic pressures induce apoptosis and oxidative stress through mitochondrial membrane depolarization in PC12 neuronal cells: A cell culture model of glaucoma

Abstract Background: Despite the importance of oxidative stress and apoptosis through mitochondrial depolarization in neurodegenerative diseases, their roles in etiology of glaucoma are poorly understood. We aimed to investigate whether oxidative stress and apoptosis formation are altered in rat pheochromocytoma-derived cell line-12 (PC12) neuronal cell cultures exposed to elevated different hydrostatic pressures as a cell culture model of glaucoma. Materials: Cultured PC12 cells were subjected to 0, 15 and 70 mmHg hydrostatic pressure for 1 and 24 h. Then, the following values were analyzed: (a) cell viability; (b) lipid peroxidation and intracellular reactive oxygen species production; (c) mitochondrial membrane depolarization; (d) cell apoptosis; (e) caspase-3 and caspase-9 activities; (f) reduced glutathione (GSH) and glutathione peroxidase (GSH-Px). Results: The hydrostatic pressures (15 and 70 mmHg) increased oxidative cell damage through a decrease of GSH and GSH-Px values, and increasing mitochondrial membrane potential. Additionally, 70 mmHg hydrostatic pressure for 24 h indicated highest apoptotic effects, as demonstrated by plate reader analyses of apoptosis, caspase-3 and -9 values. Conclusion: The present data indicated oxidative stress, apoptosis and mitochondrial changes in PC12 cell line during different hydrostatic pressure as a cell culture model of glaucoma. This findings support the view that mitochondrial oxidative injury contributes early to glaucomatous optic neuropathy.

Corneal and Tear Film Changes After Botulinum Toxin-A in Blepharospasm or Hemifacial Spasm.

Purpose: To investigate changes in corneal parameters and the tear film after botulinum toxin-A (BTX-A) injection in patients with blepharospasm or hemifacial spasm. Methods: Twelve patients with benign essential blepharospasm and 30 with hemifacial spasm treated with BTX-A were included in this study. Disease severity was evaluated using the Jankovic scale. Corneal parameters were measured by the Pentacam. The Schirmer test score, tear breakup time, corneal fluorescein staining value, and Ocular Surface Disease Index score were also evaluated. Results: The BTX-A treatment relieved spasms in all of the patients. There was a statistically significant difference in disease severity between pretreatment and the third week (2.7 ± 0.8 and 1.3 ± 0.6, respectively; P < 0.001), but there was no statistically significant difference between pretreatment and the third month (2.7 ± 0.8 and 2.7 ± 0.8, respectively; P = 0.8). The tear breakup time was found to be significantly higher at both 3 weeks and 3 months after injection (6.6 ± 4.0 at pretreatment, 8.1 ± 3.9 at the third week, and 7.8 ± 4.2 at the third month; P = 0.04 and P = 0.02, respectively). The Schirmer test score, corneal fluorescein staining values, and Ocular Surface Disease Index score were lower 3 weeks after injection, but these values increased again by 3 months after injection. Corneal astigmatism decreased significantly at 3 weeks and at 3 months after injection [1.4 ± 1.2 diopters (D) at pretreatment, 1.2 ± 0.8 D at the third week, and 1.1 ± 0.8 D at the third month, respectively; P = 0.02, for both], but other corneal parameters did not change. Conclusions: BTX-A injection therapy was affected the tear film in patients with blepharospasm or hemifacial spasm. However, there were no changes in corneal parameters, except corneal astigmatism, in these patients after treatment.

Two cases of anterior uveitis after laser eyebrow epilation.

Purpose: Laser-assisted epilation of eyebrow hair has become a common practice, but a number of ocular complications can occur. We report the cases of 2 patients who had unilateral anterior uveitis after having undergone laser removal of eyebrow hair. Methods: This report describes 2 patients who experienced eye pain, photophobia, redness, and edema after undergoing alexandrite (755 nm) laser epilation of the eyebrow area while not wearing protective eyewear or a corneal shield. Results: Eye examinations revealed that both patients had conjunctival injection, endothelial keratic precipitates, and cells in the anterior chamber of one eye. They were treated with topical cyclopentolate and steroid eye drops. Within a week, their symptoms had disappeared, and anterior chamber reactions were not seen. At their 3-month follow-ups, their visual acuity was 20/20, and eye examination results were normal for both eyes of each patient. Conclusions: Laser-assisted epilation of eyebrow hair can lead to unilateral anterior uveitis, and individuals must be informed about the risks involved in laser eyebrow epilation.

The effect of cigarette smoking on retinal nerve fiber layer thickness in patients with migraine

Abstract Context: Migraine is a frequent and disabling chronic neurological condition with complex pathophysiology. Both cigarette smoking and migraine may cause damage to the optic nerve. Objective: The primary objective of this study was to investigate the effect of cigarette smoking on retinal nerve fiber layer (RNFL) thickness in patients with migraine. Materials and methods: Eighty-four consecutive patients diagnosed with migraine (34 smokers and 50 nonsmokers) and 66 age- and gender-matched healthy non-smoker controls were enrolled for this observational cross-sectional study. RNFL thickness was measured using spectral-domain optical coherence tomography (OCT) and then RNFL thickness in patients with migraine who smoke was compared to nonsmoking patients with migraine and healthy subjects. Results: The average, superior, nasal and inferior RNFL thicknesses were significantly thinner in patients with migraine compared to the control group (p < 0.001, p = 0.02, p < 0.001 and p = 0.04, respectively). The average and inferior RNFL thicknesses were significantly reduced in smoker patients with migraine compared to the nonsmokers (p = 0.011, p = 0.045, respectively). Nonsmoker patients with migraine had significantly thinner average and nasal RNFL thicknesses than the control group (p = 0.001, p = 0.001, respectively). Conclusion: Cigarette smoking may cause significant RNFL thinning in patients with migraine. OCT may be a feasible technique for determination of smoking-induced ocular damage in patients with migraine.

The Youngest Patient with Bilateral Keratoconus Secondary to Chronic Persistent Eye Rubbing

Abstract We present the case of a four-year-old girl with bilateral keratoconus secondary to chronic persistent eye rubbing. She was referred to our clinic with intractable ocular itching and low vision. According to her family, she was generally rubbing her eyes. On slit-lamp biomicroscopic examination, bilateral papillary reactions were seen on the upper tarsal conjunctiva. Clinical examination and corneal topography were compatible with keratoconus. The patients visual acuity was not evaluated because of cooperation difficulties. Systemic examination was normal. In fact, trauma may be the common underlying factor in eye rubbing and may cause development of keratoconus, even in the early years. To the best of our knowledge, this is the youngest patient with bilateral keratoconus secondary to chronic persistent eye rubbing in the literature. Keratoconus should be kept in mind in patients with severe ocular itching, even in small children.

Is Retinal Nerve Fiber Layer Thickness Change Related to Headache Lateralization in Migraine

Purpose To evaluate retinal nerve fiber layer (RNFL) thickness in migraine patients with unilateral headache. Methods A total of 58 patients diagnosed with migraine headache consistently occurring on the same side and 58 age- and sex-matched healthy subjects were evaluated in this cross-sectional study. RNFL thickness was measured using spectral-domain optical coherence tomography, and the side with the headache was com-pared with the contralateral side as well as with the results of healthy subjects. Results The mean patient age was 33.05 ± 8.83 years, and that of the healthy subjects was 31.44 ± 8.64 years (p = 0.32). The mean duration of disease was 10.29 ± 9.03 years. The average and nasal RNFL thicknesses were significantly thinner on the side of headache and on the contralateral side compared to control eyes (p < 0.05, for all). Thinning was higher on the side of the headache compared to the contralateral side; however, this difference was not statistically significant. Conclusions The RNFL thicknesses were thinner on the side of the headache compared to the contralateral side in the migraine patients with unilateral headache, but this difference was not statistically significant.

Congenital glaucoma as an ophthalmic manifestation of Frank–Ter Haar syndrome

We report on a patient with Frank–Ter Haar syndrome that is associated with high intraocular pressures. A 21-day-old male patient was referred to our clinic for surgical treatment of congenital glaucoma. On ophthalmic examination, he had buphthalmos, mild corneal edema and high IOP readings in both eyes. The patient underwent uneventful trabeculotomy surgery, bilaterally. Marked bilateral anterior iris insertion was noted during the surgery. Childhood glaucoma may be associated with Frank–Ter Haar syndrome.

Evaluation of anterior segment parameters in patients with pseudoexfoliation syndrome using Scheimpflug imaging

PURPOSE To evaluate anterior segment parameters in patients with pseudoexfoliation syndrome (PXS) using Scheimpflug imaging. METHODS Forty-three PXS patients and 43 healthy control subjects were included in this cross-sectional study. All participants underwent a detailed ophthalmologic examination. Anterior segment parameters were measured using a Scheimpflug system. RESULTS Considering the PXS and control groups, the mean corneal thicknesses at the apex point (536 ± 31 and 560 ± 31 µm, respectively, p=0.001), at the center of the pupil (534 ± 31 and 558 ± 33 µm, respectively, p=0.001), and at the thinnest point (528 ± 30 and 546 ± 27 µm, respectively, p=0.005) were significantly thinner in PXS patients. Visual acuity was significantly lower (0.52 ± 0.37 versus 0.88 ± 0.23, p<0.001) and axial length was significantly longer (23.9 ± 0.70 mm versus 23.2 ± 0.90 mm, p=0.001) in the PXS eyes than in the control eyes. There were no statistically significant differences in the mean values of keratometry, anterior chamber angle, anterior chamber depth, corneal volume, and anterior chamber volume between the PXS and control eyes. CONCLUSIONS The patients with PXS had thinner corneas, worse visual acuity, and longer axial length compared with those in the healthy controls.

Corneal limbal sebaceous adenoma.

Purpose: The aim of this study was to describe a case of a corneal limbal sebaceous adenoma. Methods: An 83-year-old male patient presented with a white solid nodular lesion covering most of the cornea of his right eye. The corneal lesion was removed totally. The corneal surface was reconstructed by amniotic membrane transplantation. Results: The histopathological examination of the lesion revealed the presence of a sebaceous adenoma. A systemic examination revealed no other abnormalities. Conclusions: Sebaceous adenomas on the ocular surface are known to be very rare. To the best of our knowledge, this is the first case of a sebaceous adenoma located on the cornea, reported in the literature. It is of vital importance to make a differential diagnosis of sebaceous adenomas of the eyelid and conjunctiva with the Muir–Torre syndrome associated with visceral malignancies.