Browsing by Author "Simsek, S"

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Changes in Anterior Chamber Depth and Axial Length Measurements After Radial Keratotomy
(Royal Coll Ophthalmologists, 1999) Demirok, A; Çinal, A; Simsek, S; Vasar, T; Bayram, A; Yilmaz, OF
Purpose To evaluate the changes that occur in anterior chamber depth and globe axial length after radial keratotomy (RK) surgery in cases with different degrees of myopia. Methods One hundred and twelve eyes that underwent RK were studied. The eyes were divided into two groups: 70 eyes with a correction of myopia of 4.00 D and under after RK (group 1) and 42 eyes with a correction of myopia of more than 4.00 D (group 2). Routine examinations were done in all cases. Ultrasonic biometry and central anterior chamber depth and axial length were measured pre-operatively and on the third day, second week, third month and sixth month post-operatively. Results Pre-operatively the average globe axial length was longer in group 2 than group 1. When all post-operative measurements were compared with pre-operative measurements in group 1, there was a decrease in anterior chamber depth and globe axial length, but no significant difference was found except on the third day (t = 3.15, p = 0.003). In group 2 there was an insignificant decrease in axial length but the decrease in anterior chamber depth was significant at all measurement times except for the sixth month. Conclusions Refractive changes related to biometric changes after RK are not important compared with the total refractive corrections of RK. These changes should be considered, however, when planning RK procedures.
A Comparative Study on the Effect of Radial Keratotomy in Patients Who Live at Sea Level and High Altitude
(Royal Coll Ophthalmologists, 1999) Çinal, A; Yasar, T; Demirok, A; Simsek, S; Yilmaz, ÖF
Purpose To compare the refractive and keratometric results of matched pairs of patients who underwent radial keratotomy (RK) at sea level and high altitude. Methods The results of 30 eyes that underwent RK procedures in two clinical centres at different altitude were analysed. One centre was at sea level (Istanbul) and the other at an altitude of 1720 m (Van). The patients in the two centres were matched regarding gender, age, degree of myopia, number of incisions and optic zone size. There were 15 eyes in each group. All operations were performed with a diamond blade using a Russian technique by the same surgeon. Results The mean pre-operative spherical equivalent cycloplegic refractions (SECR) were -6.33 +/- 1.15 D and -6.32 +/- 1.01 D in the Istanbul and Van groups, respectively (p = 0.96). The mean post-operative SECRs were -1.93 +/- 1.03 D and -0.28 +/- 0.57 D in the Istanbul and Van groups, respectively (p < 0.001). The mean SECR changes were 4.40 +/- 0.92 D and 6.03 +/- 1.13 D in subjects who had undergone RK at sea level and at 1720 m, respectively (p < 0.001). Conclusion These results show that a higher myopic correction can be provided in patients who undergo RK at high altitude compared with those operated on at sea level. The RK nomograms used by refractive surgeons performing RK surgery at high altitude may need to be redesigned in the light of future studies with long-term follow-up.
The Effect of 0.25% Apraclonidine in Preventing Intraocular Pressure Elevation After Nd:yag Laser Posterior Capsulotomy
(Wichtig Editore, 1998) Simsek, S; Ertürk, H; Demirok, A; Cinal, A; Yasar, T; Karadenizli, G
Purpose. The efficacy and adverse effects of 0.25% apraclonidine on intraocular pressure (IOP) after Nd: YAG laser posterior capsulotomy were investigated, and the results were compared with placebo, 0.50% timolol maleate and 1% apraclonidine. Methods. Eighty eyes were randomly assigned to four groups of 20 eyes. In a double-masked design, the groups were treated with placebo (group I), 0.50% timolol maleate (group 2), 1% apraclonidine (group 3), 0.25% apraclonidine (group 4) one hour before and five minutes after Nd:YAG laser posterior capsulotomy. IOP was measured by applanation tonometry I hour before (baseline IOP) and 1, 3, 24 hours after capsulotomy. Results. The average baseline IOP increased respectively 3.90 +/- 5.35, 5.95 +/- 5.32, 1.15 +/- 3.20 mmHg in the first group 1, 3 and 24 hours post-treatment. There were significant differences between baseline IOP and 1 and 3 hours but not at 24 hours (p=0.004, p=0.001, p=0.13). IOP increased 0.40 +/- 4.08, 0.75 +/- 5.33, 0.80 +/- 6.03 mmHg in the second group at the same times. The differences between the average baseline IOP and the 1, 3 and 24 h measurement were not significant (p=0.83, p=0.65, p=0.93). In the third group, IOP decreased 3.70 +/- 2.40, 3.30 +/- 2.47, 2.65 +/- 1.56 mmHg at the measurement times, with significant differences between the average baseline IOP and the 1, 3 and 24 hour measurements (p=0.001, p=0.0001, p=0.01). In the fourth group IOP increased 0.35 +/- 3.32 mmHg at 1 hour, but decreased 1.25 +/- 3.41, 0.90 +/- 2. 07 mmHg at 3 and 24 hours. The differences were not significant (p = 0.94, p = 0.16, p = 0.08). When the 0.25% and 1% apraclonidine groups were compared, there were significant differences between the average IOP at 1 hour in both groups but not at 3 and 24 hours (p=0.01, p = 0.17, p = 0.21). Similarly, there were no significant differences between the average IOP at the same times when the 0.25% apraclonidine group was compared with the timolol group (p = 0.30, p = 0.08, p = 0.16). Some systemic and local side effects were seen in the timolol and 1% apraclonidine groups, but none with 0.25% apraclonidine. Conclusions. It was concluded that 0.25% apraclonidine is effective in preventing the early elevation of IOP after Nd:YAG laser posterior capsulotomy and may offer an alternative to 0.50% timolol maleate and 1% apraclonidine.
The Effect of Altitude on Radial Keratotomy
(Elsevier Science inc, 1998) Simsek, S; Demirok, A; Cinal, A; Yasar, T; Yilmaz, OF
The authors analyzed refractive results of patients who underwent radial keratotomy (RK) at sea level and high altitude and evaluated the effects of the altitude. A total of 102 eyes undergoing RK procedures performed in two clinical centers having different altitude were analyzed. The results compared between subjects who had undergone RK at sea level (Istanbul/Turkey) and at an altitude of 5750 feet (Van/Turkey) were compared. Subjects were 19-42 years old with myopia from -4.00 to -12.00 diopters (D). The average preoperative spherical equivalent cycloplegic refractions (SECR) were -8.01 +/- 1.86 D and -6.99 +/- 2.15 D in the istanbul and Van groups, respectively. These were divided into subgroups according to myopia degree and number of incisions and optic zone size. The RK procedures were performed by the same surgeon with diamond blade in standard Russian style. The average changes in SECR were 5.09 +/- 1.29 D and 6.50 +/- 2.24 D in subjects who had undergone RK at sea level and at 5750 feet, respectively. There was a significant difference between the subgroups (P < 0.0002). This difference was especially higher in the high myopia subgroups. Additionally, we obtained a partial relation between increase of RK incision number and SECR change at high altitude but not at sea level. No notable regression and progression were seen in the 3 months of follow up at high altitude. These results support hy potheses suggesting both corneal hypoxic expansion in the area of RK incisions, which may lead to central corneal flattening, and barometric pressure directly altering corneal shape, which is responsible for the hyperopic shift induced by altitude. Ophthalmologists performing RK surgery at high altitude had better consider redesigning their RK nomograms in light of these findings. However, when the nomogram used at sea level was used at high altitude, the subjects became hyperopic. (C) 1998 Japanese Ophthalmological Society.
Effect of Sex in Branch Retinal Vein Occlusion
(Wichtig Editore, 1998) Simsek, S; Demirok, A; Çinal, A; Yasar, T
Purpose. To evaluate the effect of sex in relation to crossing numbers, arterial overcrossings and occlusion sites in patients with branch retinal vein occlusion (BRVO). Methods. Fifty-one eyes with BRVO (study group) and 48 eyes with retinal problems other than BRVO (control group) were investigated All venous occlusions were examined in detail with regard to their anatomical positions, sites and arteriovenous crossings on the retinal surrounding area two disc diameters nasally, four disc diameters temporally three disc diameters superiorly and three inferiorly from the optic disc, in the arteriovenous phase of fundus fluorescein angiography and fundus color photography. Results. The study group comprised 29 women (56.86%) and 22 men (43.14%). All occlusions were unilateral and located at the crossing areas. BRVO had arterial overcrossing in 28 eyes (96.6%) in females and 22 eyes (95.5%) in males (p > 0.005). The average numbers of crossings were 7.79 +/- 1.57 in females and 7.82 +/- 1.05 in males in the study group (p > 0.05), and respectively 7.30 +/- 1.19 and 6.95 +/- 1.13 (p > 0.05) in the control group. The average arterial overcrossing ratios were 75% in females and 71% in males in the study group (p > 0.05), and 74% and 65% in the control group (p > 0.05). Conclusions. Our data suggest that females ha ve a higher risk than males because of their arterial overcrossing ratio and BRVO prefer arterial overcrossing. However the insignificant difference between the female and male patients leads us to assume that the effect of sex on BRVO cannot be explained only by local anatomical factors since their effect is only slight.
Effect of Superior and Temporal Clear Corneal Incisions on Astigmatism After Sutureless Phacoemulsification
(Elsevier Science inc, 1998) Simsek, S; Yasar, T; Demirok, A; Cinal, A; Yilmaz, OF
Purpose: To evaluate the effect of superior and temporal clear corneal incisions on astigmatism after sutureless, small incision phacoemulsification. Setting: World Eye Hospital, Istanbul, Turkey. Methods: This prospective study evaluated 40 eyes of 20 patients with cataract having bilateral, sutureless, small incision phacoemulsification by the same surgeon. A superior clear corneal incision was used in all right eyes and a temporal clear corneal incision in ail left eyes. Mean preoperative astigmatism was 0.63 diopter(D) +/- 0.21 (SD) and 0.65 +/- 0.20 D, respectively. Mean patient age was 66.45 years. Patients were examined preoperatively and 1 day, 1 week and 1 and 3 months postoperatively. Results: Three months postoperatively, mean astigmatism was 1.60 +/- 0.37 D in the superior incision group and 0.83 +/- 0.19 D in the temporal incision group. Induced astigmatism calculated by vector analysis was 1.44 +/- 0.31 D and 0.62 +/- 0.28 D, respectively. The temporal incision group had significantly lower astigmatism at all follow-ups (P = .000). Conclusion: Upper lid pressure on the superior corneal incisions led to fluctuating, against-the-rule astigmatism that was significantly higher than that induced by temporal incisions.
Effects of 0.5% and 0.25% Apraclonidine on Postoperative Intraocular Hypertension After Cataract Extraction
(Wichtig Editore, 1998) Simsek, S; Demirok, A; Yasar, T; Çinal, A; Bayram, A; Yilmaz, ÖF
Purpose. We conducted a double-masked, prospective study to evaluate the effect of 0.5% and 0.25% apraclonidine on postoperative intraocular pressure (IOP) in patients undergoing extracapsular cataract extraction (ECCE) with intraocular lens (IOL) implantation. Methods. Fifty-four patients scheduled for ECCE were randomly divided into three groups of 18. The first group received one drop of 0.50% apraclonidine topically one hour before surgery and immediately after the end of the procedure. The second group received the same regimen but with 0.25% apraclonidine. The third group received artificial fears as the control group. IOP was measured 12 h preoperatively and 6 and 24 h postoperatively. All the measurements were made using the same Goldmann applanation tonometer by the same surgeon who did not know to which group the patient belonged. Results. Preoperative mean IOP was 13.66 +/- 2.76 mmHg in the first group, 14.27 +/- 2.24 mmHg in the second and 14.5 +/- 1.34 mmHg in the control group. The differences were not significant (p = 0.398). Mean IOP at the early postoperative visit (6 h) was significantly lower in the first group (17.44 +/- 4.95 mmHg) than the second (21.78 +/- 7.19 mmHg) and the control group (24.55 +/- 5.65 mmHg) (p < 0.001). Mean postoperative IOP at 24 h was again significantly lower in the first group (14.33 +/- 3.75 mmHg) than the second (17.11 +/- 14.16 mmHg) and the control group (19.61 +/- 3.20 mmHg) (p < 0.001). Conclusions. Our findings indicate that topical 0.5% apraclonidine controlled early postoperative intraocular hypertension after cataract extraction without any side effects, while the 0.25% drops were not effective.
Intraoperative Application of Mitomycin C in the Surgical Treatment of Pterygium
(Wichtig Editore, 1998) Demirok, A; Simsek, S; Çinal, A; Yasar, T
Purpose. To investigate the effectiveness of intraoperative mitomycin C in pterygium surgery. Methods. The effectiveness of intraoperatively administered mitomycin C and the occurrence of postoperative complications were evaluated in 17 patients with two recurrences of pterygium. The authors employed the "bare-sclera technique" and placed a sterile sponge soaked in a 0.02% mitomycin C solution intraoperatively in the episcleral space for 3 minutes. The control group (15 patients) underwent only surgical excision. Patients were followed for 21 to 30 months. Results. The pterygium recurred in one (5.9%) of the 17 patients in group 1 and in six (40%) of the 15 controls. Statistical analysis using Fisher's exact test showed a significant (p=0.027) reduction of recurrences of pterygium in the group treated intraoperatively with mitomycin C. No serious complications or side effects arose during the follow-up period. Conclusions. Mitomycin C administered intraoperatively can be considered an effective treatment to improve the success rate after surgical excision.
Latanoprost Therapy in Patients With Glaucoma and Ocular Hypertension Inadequately Controlled With Carteolol
(Springer Japan Kk, 2004) Yasar, T; Ozdemir, M; Andi, I; Ozdemir, G; Simsek, S
Peribulbar Anesthesia: One Versus Two Injections
(Slack inc, 1997) Demirok, A; Simsek, S; Cinal, A; Yasar, T
BACKGROUND AND OBJECTIVE: The authors describe their prospective, randomized study of a single peribulbar injection into the junction of the lateral third and medial two thirds of the lower lid compared with the standard two-injection peribulbar technique. PATIENTS AND METHODS: One hundred twenty patients undergoing elective intraocular surgery were randomly allocated to receive either one or two injections of a mixture of balanced salt solution, 2% lidocaine, 0.5% bupivacaine, and hyaluronidase. Preoperative akinesia was assessed following the injections. At the end of surgery, the patients were asked if they had experienced any pain or discomfort during surgery. RESULTS: There was no significant difference in pain or globe akinesia between the two groups. CONCLUSION: The single peribulbar injection was found to be as effective as the standard two-injection peribulbar technique.