Mehmet Okka

Effect of altered eating habits and periods during Ramadan fasting on intraocular pressure, tear secretion, corneal and anterior chamber parameters.

PurposeTo determine whether altered eating habits and periods, especially the pre-dawn meal, during Ramadan fasting have any significant effect on intraocular pressure (IOP), tear secretion, corneal and anterior chamber parameters.MethodsIOP, basal tear secretion (BTS), reflex tear secretion (RTS), and Pentacam measurements of 31 healthy volunteers were performed at 0800 and 1600 hours during Ramadan fasting and 1 month later during non-fasting period.ResultsComparison of measurements between fasting and non-fasting periods at 0800 hours revealed significantly higher values for IOP (P=0.005), RTS (P=0.006), and BTS (P=0.014) during fasting. Conversely at 1600 hours, IOP was significantly lower during fasting (P=0.013) and no statistically significant difference was noted for RTS and BTS. IOP showed a diurnal variation of 2.45 mmHg (P<0.001) and BTS showed a 3.06 mm decrease (P=0.04) during the fasting period. No significant differences could be found in the corneal and anterior chamber parameters during fasting and non-fasting periods.ConclusionsOur results revealed that fluid loading at the pre-dawn meal during Ramadan fasting might increase the IOP and tear secretion in the early morning period and these values decrease remarkably at the end of 12 h of fasting due to dehydration.

Does lens status affect the course of early intraocular pressure and anterior chamber changes after intravitreal injection

Purpose:  This study aimed to observe changes in anterior chamber parameters and the course of intraocular pressure (IOP) after injection of 0.1 ml intravitreal triamcinolone acetonide (TA) and to determine differences between phakic and pseudophakic eyes without vitreous reflux.

The Evaluation of Retinal Nerve Fiber Layer Thickness in Patients with Obstructive Sleep Apnea Syndrome

Aim. To evaluate the retinal nerve fiber layer (RNFL) thickness in patients with obstructive sleep apnea syndrome (OSAS) by optical coherence tomography (OCT). Materials and Method. We studied 43 new diagnosed OSAS patients and 40 healthy volunteers. Patients underwent an overnight sleep study in an effort to diagnose and determine the severity of OSAS. RNFL analyses were performed using Stratus OCT. The average and the four-quadrant RNFL thickness were evaluated. Results. There was no difference between the average and the four-quadrant RNFL thickness in OSAS and control groups. There was no correlation between apnea-hypopnea index and intraocular pressure. Body mass index of patients with moderate and severe OSAS was significantly higher in patients with mild OSAS. Conclusion. Mean RNFL thickness did not differ between the healthy and the OSAS subjects, however, the parameters were more variable, with a larger range in OSAS patients compared to controls.

Control of steroid-induced glaucoma with surgical excision of sub-Tenon triamcinolone acetonide deposits: a clinical and biochemical approach

OBJECTIVE To assess the efficacy of surgical excision of sub-Tenon triamcinolone acetonide (TA) deposits in the control of steroid-induced glaucoma. DESIGN Prospective, nonrandomized, interventional case series. PARTICIPANTS Eighteen eyes of 14 subjects with increased IOP within 6 months of sub-Tenon TA injection who did not respond to medical antiglaucomatous treatment were included in the study. METHODS Under topical anaesthesia, steroid deposits were completely excised and placed in ethyl alcohol for the determination of the TA amount using high-performance liquid chromatography. The patients were followed up for 6 months and a paired-sample t test was used to compare mean IOP before and after excision of sub-Tenon TA deposits. RESULTS The mean IOP levels before and after the sub-Tenon steroid injections were 15.9 (SD 2.9) mm Hg and 36.4 (SD 8.4) mm Hg, respectively (p < 0.001). IOP levels decreased significantly after the removal of the deposits (mean 15.3 [SD 2.1] mm Hg) (p < 0.001). Within 6 months of follow-up, all glaucoma medications were stopped in 9 subjects without further IOP increase, whereas IOP control in 5 subjects necessitated using glaucoma medications. The median TA amount was found to be 7.35 mg (range 3.3-29.68 mg). IOP decrease after the excision showed no correlation with the amount of TA (p = 0.8). CONCLUSIONS Surgical excision of the sub-Tenon steroid deposit should be considered as the primary treatment for steroid-induced glaucoma refractory to medical treatment.

Cluster headache with ptosis responsive to intranasal lidocaine application: a case report

IntroductionThe application of lidocaine to the nasal mucosal area corresponding to the sphenopalatine fossa has been shown to be effective at extinguishing pain attacks in patients with a cluster headache. In this report, the effectiveness of local administration of lidocaine on cluster headache attacks as a symptomatic treatment of this disorder is discussed.Cases presentationA 22-year-old Turkish man presented with a five-year history of severe, repeated, unilateral periorbital pain and headache, diagnosed as a typical cluster headache. He suffered from rhinorrhea, lacrimation and ptosis during headaches. He had tried several unsuccessful daily medications. We applied a cotton tip with lidocaine hydrochloride into his left nostril for 10 minutes. The ptosis responded to the treatment and the intensity of his headache decreased.ConclusionIntranasal lidocaine is a useful treatment for the acute management of a cluster headache. Intranasal lidocaine blocks the neural transmission of the sphenopalatine ganglion, which contributes to the trigeminal nerve as well as containing both parasympathetic and sympathetic fibers.

GAPO syndrome: Four new patients with congenital glaucoma and myelinated retinal nerve fiber layer†‡

This 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.

Cavernous hemangioma with cone dysfunction.

We report a 13-year-old male who complained of strabismus and low visual acuity in the right eye. Saccular aneurysms filled with dark-colored blood were noted in the upper nasal quadrant of the right fundus. Ishihara color plates and Lanthonys new color test revealed a red-green color defect. Cone response and 30-Hz flicker responses were nearly absent. Cavernous hemangioma of the retina is a rare vascular hamartoma; the associated findings show cone dysfunction concomitant with this peripheral lesion.

Pattern-reversal electroretinograms and visual evoked potentials in branch retinal vein occlusion

We recorded pattern electroretinograms and visual evoked potentials in a group of selected patients with unilateral uncomplicated branch retinal vein occlusion. To document the effects of preexisting risk factors, patients were divided into three groups: diabetes mellitus, hypertension with hyperlipidemia and no systemic disease. The transient and steady-state pattern electroretinogram and visual evoked potential amplitudes were significantly reduced and visual evoked potential peak times were delayed relative to the fellow eyes and agematched normal subjects. There was a second amplitude reduction relative to the other patient groups in both the affected and fellow eyes of the diabetes mellitus group, which was indicative of an additive effect of diabetes mellitus.

The Effect of Dehydration and Fasting on Corneal Biomechanical Properties and Intraocular Pressure.

Purpose: To evaluate the changes in corneal biomechanical properties and intraocular pressure (IOP) during fasting period in healthy subjects. Methods: Seventy-two eyes of 72 fasting subjects (study group), and 62 eyes of 62 nonfasting subjects (control group) were enrolled in this prospective study undertaken at a single university hospital. All subjects underwent complete ophthalmologic examination including ocular biomechanical evaluation with ocular response analyzer. Ocular response analyzer measurement was performed on the right eyes of the subjects between 5.00 and 6.00 PM after approximately 14 hr of fasting for the study group and after a nonfasting period for the control group. The corneal hysteresis, corneal resistance factor, mean corneal compensated IOP (IOPcc), and Goldmann-correlated IOP (IOPg) values were measured with a patented dynamic bidirectional applanation process. Results: Goldmann-correlated IOP and IOPcc measurements in the study group and the control group were found as 13.8±2.8 mm Hg, 14.6±2.6 mm Hg and 16.3±2.2 mm Hg, 15.7±2.4 mm Hg, respectively. There was statistically significant difference within the two groups in IOPg and IOPcc (P<0.001). In addition, corneal hysteresis and corneal resistance factor significantly decreased in study group compared with control group (P<0.001, P=0.012, respectively). Conclusion: Prolonged fasting causes a significant decrease in IOPg, IOPcc, corneal hysteresis, and corneal resistance factor in healthy subjects, altering the biomechanical properties of the cornea.

Effect of mydriasis induced by topical 0.5% tropicamide instillation on the corneal biomechanical properties in healthy individuals measured by ocular response analyzer

Abstract Purpose: 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.