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Ahmet Akman

Leukotrienes have been shown to play a role in the pathogenesis of ocular inflammatory and allergic reactions like vernal keratoconjunctivitis and contact lens-associated giant papillary conjunctivitis. This study was designed to... more
Leukotrienes have been shown to play a role in the pathogenesis of ocular inflammatory and allergic reactions like vernal keratoconjunctivitis and contact lens-associated giant papillary conjunctivitis. This study was designed to determine leukotriene B4 (LTB4) and leukotriene C4 (LTC4) levels in the tears of patients with ocular prosthesis-associated giant papillary conjunctivitis (OP-GPC) and to evaluate the effects of lodoxamide 0.1% on tear LTB4 and LTC4 levels of OP-GPC patients. Tear LTB4 and LTC4 levels were determined by an ELISA technique in the tears of ten OP-GPC patients before and after treatment with lodoxamide 0.1% for one month. The results were compared with that of ten healthy control subjects. The mean tear LTB4 and LTC4 levels of the OP-GPC patients were significantly higher than those of the control group. After treatment with lodoxamide 0.1%, tear LTB4 and LTC4 levels of the OP-GPC patients decreased significantly. This is the first report of elevated LTB4 and LTC4 levels in tears of OP-GPC patients and it points to the possible role of leukotrienes in the immunopathogenesis of OP-GPC. The results also indicate that lodoxamide 0.1%, a mast cell membrane stabilizer, is effective in significantly reducing tear LTB4 and LTC4 levels in OP-GPC patients.
To investigate and compare the effects of suramin and mitomycin C on conjunctival wound healing after trabeculectomy in a rabbit model. Thirty New Zealand White rabbits were divided into three groups, and trabeculectomy was performed on... more
To investigate and compare the effects of suramin and mitomycin C on conjunctival wound healing after trabeculectomy in a rabbit model. Thirty New Zealand White rabbits were divided into three groups, and trabeculectomy was performed on the left eyes under general anesthesia. During the surgery, suramin (250 mg/ml) and mitomycin C (0.4 mg/ml) were applied to the scleral flap site for 2 minutes in groups 1 and 2, respectively. The control animals (group 3) received no pharmacological treatment during trabeculectomy. Intraocular pressure (IOP) measurements were recorded before surgery and every 3 days after the operation, starting from postoperative day 1. Three animals from each group were sacrificed on days 15, 20, and 25, yielding a total of 27 eyes for histopathological study. Each specimen was histochemically and immunohistochemically (CD3, CD20, CD68, and collagen III) evaluated, and graded. Bleb failure time was significantly longer in both the suramin (15.0 +/- 4.7 days) and mitomycin C (16.7 +/- 5.1 days) groups than in the controls (10.3 +/- 4.2 days) (p < 0.05). Starting from postoperative day 9, the IOP in the suramin and mitomycin C groups was significantly lower than that in the control group (p < 0.05). This difference continued to be significant until day 18 for the suramin group, and until day 24 in the mitomycin C group. Histopathological evaluation showed lower degrees of cellularity, fibrosis, collagen III deposition, and CD3 density in the suramin- and mitomycin C-treated eyes compared to control eyes at all time points (p < 0.05). There was also no significant difference between the suramin and mitomycin C groups concerning these histopathological findings and CD3 density (p > 0.05). Although there were trends towards reduced mean elastic fiber deposition and lower CD20 and CD68 density in both groups of treated eyes, the differences between the treated and control groups were not significant (p > 0.05). The results of the current study suggest that suramin has beneficial effects on wound healing in glaucoma surgery, and effectively prolongs bleb survival in rabbits. Suramin may be a promising alternative to anti-metabolite therapy in glaucoma surgery.
To determine whether the mydriatic efficacy of spray application of tropicamide 1% is comparable to drop instillation of tropicamide 1%, and to compare the ocular discomfort caused by these methods. Thirty-four healthy volunteers were... more
To determine whether the mydriatic efficacy of spray application of tropicamide 1% is comparable to drop instillation of tropicamide 1%, and to compare the ocular discomfort caused by these methods. Thirty-four healthy volunteers were randomly assigned to one of two groups, and received either a single drop of tropicamide 1% eye drops or a single puff of tropicamide 1% spray into open eyes. Pupil diameters were measured from anterior segment images taken using a Topcon Imagenet system at baseline and at the fifth, tenth and fifteenth minute after drug administration. Ocular discomfort experienced with each method was also compared. Repeated measures analysis of variance revealed that a statistically significant increase in pupil diameter was achieved with both application methods over time (p < 0.0001), and that there were no statistically significant differences in pupil diameter between the two groups at each time point (p = 0.409). The mean ocular discomfort score for tropicamide 1% spray was 1.45 +/- 0.56, and for tropicamide 1% eye drops was 2.71 +/- 0.67. This difference was statistically significant (p < 0.001). The mydriatic efficacy of tropicamide 1% spray is similar to that of conventional tropicamide 1% eye drops, and spray application causes less ocular discomfort.
The CREST syndrome is a variant form of progressive systemic sclerosis. Apart from the occurrence of keratoconjunctivitis sicca, other types of ocular involvement associated with this variant are quite rare. We present the case of a... more
The CREST syndrome is a variant form of progressive systemic sclerosis. Apart from the occurrence of keratoconjunctivitis sicca, other types of ocular involvement associated with this variant are quite rare. We present the case of a 73-year-old woman with the CREST variant of progressive systemic sclerosis who developed unilateral granulomatous anterior uveitis. Systemic and laboratory testing failed to suggest evidence for any other associated systemic disease as a possible cause of the granulomatous uveitis. The inflammation was successfully controlled with topical steroids and mydriatics. While a small number of cases of uveitis have been reported in other variant forms of progressive systemic sclerosis, to date there have been no descriptions of uveitis associated with the CREST syndrome.
The CREST syndrome is a variant form of progressive systemic sclerosis. Apart from the occurrence of keratoconjunctivitis sicca, other types of ocular involvement associated with this variant are quite rare. We present the case of a... more
The CREST syndrome is a variant form of progressive systemic sclerosis. Apart from the occurrence of keratoconjunctivitis sicca, other types of ocular involvement associated with this variant are quite rare. We present the case of a 73-year-old woman with the CREST variant of progressive systemic sclerosis who developed unilateral granulomatous anterior uveitis. Systemic and laboratory testing failed to suggest evidence for any other associated systemic disease as a possible cause of the granulomatous uveitis. The inflammation was successfully controlled with topical steroids and mydriatics. While a small number of cases of uveitis have been reported in other variant forms of progressive systemic sclerosis, to date there have been no descriptions of uveitis associated with the CREST syndrome.
To investigate levels of vascular endothelial growth factor (VEGF) and nitric oxide (NO) in the aqueous humor and plasma of patients with pseudoexfoliation syndrome (PXS) and pseudoexfoliation glaucoma (PXG), compared with controls. This... more
To investigate levels of vascular endothelial growth factor (VEGF) and nitric oxide (NO) in the aqueous humor and plasma of patients with pseudoexfoliation syndrome (PXS) and pseudoexfoliation glaucoma (PXG), compared with controls. This prospective study involved 37 patients with PXS, 15 with PXG, and 32 control subjects in whom cataract surgery was indicated. Aqueous humor and plasma VEGF and NO levels were measured with enzyme-linked immunosorbent assay and chemiluminescence methods, respectively. Aqueous humor and plasma VEGF concentrations were higher in patients with PXS and PXG than in controls (P<0.001). Aqueous humor NO concentrations were higher in patients with PXS and PXG than in controls (P<0.05 and P=0.001, respectively). Plasma NO concentrations did not differ between the 3 groups. Aqueous humor and plasma VEGF and NO levels were not significantly different in patients with PXS versus PXG. VEGF and NO levels showed no significant correlation among the 3 groups (P>0.05). Elevated aqueous humor VEGF and NO levels and plasma VEGF concentrations in eyes with PXS and PXG can be explained by the ischemic nature of these disorders. The lack of correlation between VEGF and NO levels may indicate impaired downregulation, which may have a role in the progression to PXG.
To compare the effectiveness of brinzolamide 1% (Azopt) and brimonidine 0.2% (Alphagan) with a placebo in preventing an early increase in intraocular pressure (IOP) after phacoemulsification. Department of Ophthalmology, Baskent... more
To compare the effectiveness of brinzolamide 1% (Azopt) and brimonidine 0.2% (Alphagan) with a placebo in preventing an early increase in intraocular pressure (IOP) after phacoemulsification. Department of Ophthalmology, Baskent University, School of Medicine, Ankara, Turkey. In this prospective double-masked study, 90 eyes of 90 patients having clear corneal phacoemulsification were randomly divided into 3 groups of 30 eyes each. One hour before surgery, 1 group received 1 drop of brinzolamide 1%, another received 1 drop of brimonidine 0.2%, and the third received 1 drop of a balanced saline solution (placebo). The IOP was measured preoperatively and 3 and 16 to 20 hours postoperatively. Three hours postoperatively, the mean IOP increased by 4.2 mm Hg +/- 7.0 (SD), 3.2 +/- 6.4 mm Hg, and 5.3 +/- 4.2 mm Hg in the brinzolamide, brimonidine, and placebo groups, respectively. The IOP increase from baseline was significant in all 3 groups (all P<.01), with no difference between the groups (P>.05). The change in IOP at 16 to 20 hours was 0.2 +/- 2.8 mm Hg, 0.2 +/- 2.4 mm Hg, and -0.8 +/- 2.4 mm Hg, respectively. The changes were not significant compared to baseline (all P>.05). Six eyes (20%) in the brinzolamide group, 5 eyes (16.7%) in the brimonidine group, and 7 eyes (23.3%) in the placebo group had an IOP higher than 25 mm Hg 3 hours postoperatively; the difference between groups was not significant (P =.8). Prophylactic use of 1 drop of brinzolamide or brimonidine was not more effective than a placebo in controlling early postoperative IOP elevations after clear corneal phacoemulsification.
To evaluate the safety of suramin compared with mitomycin-C (MMC) as an adjunctive agent in trabeculectomy by determining its ciliary body toxicity at predetermined effective dosages in rabbit eyes. Thirty-two New Zealand albino rabbits... more
To evaluate the safety of suramin compared with mitomycin-C (MMC) as an adjunctive agent in trabeculectomy by determining its ciliary body toxicity at predetermined effective dosages in rabbit eyes. Thirty-two New Zealand albino rabbits received either suramin (200, 300, 400, or 800 mg/ml) or MMC (0.2, 0.3, 0.4, or 0.8 mg/ml) injections subconjunctivally in the right eye. Enucleations were performed on the 1st, 3rd, 7th and 28th day. Untreated left eyes were injected with balanced salt solution and served as controls. The injection-exposed ciliary body specimens were processed to be investigated under the light microscope and transmission electron microscope. There was no pathologic abnormality in specimens under light microscopy. The morphologic evaluation with transmission electron microscopy showed severe changes in structure, except for eyes treated with 200 mg/ml suramin and 0.2 mg/ml of MMC. These changes were more prominent in eyes exposed to MMC, and appeared earlier compared to suramin-treated eyes. Suramin 200 mg/ml and MMC 0.2 mg/ml seem to be comparatively nontoxic to the ciliary body of the rabbit eye. Concentrations higher than these values caused severe damage.
Purpose:  We aimed to compare the clinical efficacy and ocular surface variables of olopatadine, ketotifen fumarate, epinastine, emedastine and fluorometholone acetate ophthalmic solutions in preventing the signs and symptoms of seasonal... more
Purpose:  We aimed to compare the clinical efficacy and ocular surface variables of olopatadine, ketotifen fumarate, epinastine, emedastine and fluorometholone acetate ophthalmic solutions in preventing the signs and symptoms of seasonal allergic conjunctivitis (SAC).Methods:  This was a prospective, randomized, double-blinded and placebo-controlled study. A total of 100 patients with SAC were randomly assigned to one of five groups, in which they were administered olopatadine, ketotifen fumarate, epinastine, emedastine or fluorometholone acetate, instilled twice daily for 2 weeks. One eye of each patient was treated with the study drug and the other was treated with a placebo. Signs and symptoms of allergic conjunctivitis (itching, redness, tearing, chemosis and eyelid swelling) were scored on a 4-point scale. Each symptom was assessed at baseline and then again after 1 and 2 weeks of treatment. Ocular surface variables were assessed by conjunctival impression cytology.Results:  At weeks 1 and 2, all antiallergic agents were significantly more effective than placebo in alleviating itching, redness, tearing, chemosis and eyelid swelling. Fluorometholone acetate was significantly less effective than the other agents in reducing itching and redness at all control visits. Ocular surface findings by impression cytology improved significantly after all treatments compared with placebo.Conclusions:  In patients with SAC, olopatadine, ketotifen, epinastine and emedastine are more efficacious than fluorometholone acetate in preventing itching and redness. All the antiallergic agents gave similar results in terms of reducing tearing, chemosis and eyelid swelling. Our data showed that impression cytology parameters improved after treatment with antiallergic agents in patients with SAC.
To compare the effectiveness of brinzolamide 1%, brimonidine 0.2%, acetazolamide 250 mg, intracameral acetylcholine, and timolol 0.5% in preventing intraocular pressure (IOP) peaks during the early period after phacoemulsification in... more
To compare the effectiveness of brinzolamide 1%, brimonidine 0.2%, acetazolamide 250 mg, intracameral acetylcholine, and timolol 0.5% in preventing intraocular pressure (IOP) peaks during the early period after phacoemulsification in which sodium chondroitin sulfate 4%-sodium hyaluronate 3% (Viscoat) was used as the ophthalmic viscosurgical device (OVD). Department of Ophthalmology, Baskent University Medical Faculty, Ankara, Turkey. This prospective randomized study comprised 185 eyes of 185 patients with uncomplicated cataract scheduled for phacoemulsification using Viscoat as the OVD. Patients were randomly assigned to 1 of 6 groups: postoperative application of topical brinzolamide 1%, brimonidine 0.2%, oral acetazolamide 250 mg, intracameral acetylcholine, timolol 0.5%, or no ocular hypotensive agent (control group). The IOP was measured at baseline (preoperatively) as well as 6 hours, 20 to 24 hours, and 1 week after surgery. The mean preoperative IOP values were not significantly different between the groups. Six hours and 20 to 24 hours postoperatively, the mean IOP was significantly lower in all groups receiving an ocular hypotensive agent than in the control group (P<.01). Six hours after surgery, the mean IOP significantly increased in all groups but was higher in the control group. At 20 to 24 hours, the mean IOP decreased significantly in all ocular hypotensive agent groups but remained significantly high in the control group. One week after surgery, there were no significant differences between the groups. Brinzolamide, brimonidine, acetazolamide, intracameral acetylcholine, and timolol had similar effects in reducing IOP increases after phacoemulsification performed using Viscoat.
To evaluate the relationship of intraoperative floppy iris syndrome with pseudoexfoliation, diabetes mellitus, hypertension, and alpha-1 adrenergic blocker (A1AB) use. Five hundred patients were included in this prospective study.... more
To evaluate the relationship of intraoperative floppy iris syndrome with pseudoexfoliation, diabetes mellitus, hypertension, and alpha-1 adrenergic blocker (A1AB) use. Five hundred patients were included in this prospective study. Intraoperative adverse events, such as pupillary constriction, iris billowing, and iris prolapse from the wound, were noted. Multinomial regression analysis was used to evaluate the relationship of intraoperative floppy iris syndrome with pseudoexfoliation, diabetes mellitus, hypertension, pupil diameter, and A1AB use. Pupil constriction was significantly associated with pseudoexfoliation (P < .001). Diabetes mellitus was associated with pupil constriction and iris billowing (P = .005 and .003, respectively). Hypertension was associated with pupil constriction (P = .021). Intraoperative floppy iris syndrome was strongly associated with A1AB use and male gender (P < .001 and .039, respectively). Intraoperative floppy iris syndrome was observed in 2.8% of patients and was strongly related to A1AB use, particularly in smaller pupil diameters. Pseudoexfoliation, diabetes mellitus, and hypertension were not associated with intraoperative floppy iris syndrome.
To compare 4 methods for intraoperative pupil dilatation in eyes with pseudoexfoliation syndrome and insufficient pupil size during phacoemulsification. Prospective, randomized, comparative, interventional case series. Forty eyes of 40... more
To compare 4 methods for intraoperative pupil dilatation in eyes with pseudoexfoliation syndrome and insufficient pupil size during phacoemulsification. Prospective, randomized, comparative, interventional case series. Forty eyes of 40 patients with pseudoexfoliation and maximally dilated pupil size smaller than 3.5 mm. Mechanical pupil dilatation with iris-retractor hooks (group I), polymethyl methacrylate (PMMA) pupil dilator-ring (Morcher, Stuttgart, Germany) (group II), Beehler pupil dilator (group III), and bimanual stretching (group IV). Performance (pupil size achieved), complications, and added surgical time. The mean pupil sizes achieved with the PMMA pupil-dilator ring, Beehler pupil dilator, and bimanual stretching were 5.9+/-0.6 mm, 5.5+/-0.8 mm, and 4.9+/-0.7 mm, respectively. A square-shaped pupil was achieved with iris-retractor hooks, and the mean size of the largest circle that can fit in this square was 5.6+/-0.6 mm. There were no statistically significant differences in the postdilatation pupil sizes between the 4 study groups (P>0.05). Apart from self-limited intraoperative hemorrhage from pupil margin, iris sphincter rupture was the only observed complication related to mechanical pupil dilatation. This occurred in 4 eyes in groups I and III, 3 eyes in group IV, and 1 eye in group II (P>0.05). The mean added surgical time for placement of iris-retractor hooks and for implantation of a PMMA pupil-dilator ring was 297+/-51 and 176+/-54 seconds, respectively. The additional time required for pupil dilatation with the Beehler pupil dilator and bimanual stretching was 65+/-8 and 55+/-10 seconds, respectively. The time needed for pupil dilatation in groups I and II is significantly longer than that in groups III and IV (P<0.001). All 4 methods used in this study were effective procedures for the mechanical dilatation of small pupils secondary to pseudoexfoliation syndrome. Iris-retractor hooks and the PMMA pupil-dilator ring are the most time-consuming techniques but have the advantage of a stable pupil size throughout the surgery. The PMMA pupil-dilator ring causes the least iris trauma. The Beehler pupil dilator and bimanual stretching technique were the least time-consuming methods for mechanical pupil dilatation.