Fatih Ulaş

Effects of Amniotic Membrane Transplantation and Mitomycin C on Wound Healing in Experimental Glaucoma Surgery

Purpose: To evaluate the effects of mitomycin C and amniotic membrane transplantation on the modulation of wound healing after glaucoma filtration surgery. Methods: Trabeculectomy was performed in 3 groups of 10 rabbit eyes each. Sponges soaked in mitomycin C were applied to the first group, and amniotic membranes were transplanted around the scleral flap in the second group; the third group was the control. The arithmetic means of fibroblast and macrophage numbers per square centimetre were calculated. Results: The mean numbers of fibroblasts and macrophages were decreased significantly in the mitomycin C group, compared with the controls (p < 0.0001). Cell counts in the amniotic membrane group were also lower than the ones in the control group for fibroblasts and macrophages (p < 0.0001, p < 0.01, respectively). The difference between the two treatment groups was statistically significant for fibroblasts (p < 0.0001), but not significant for macrophages (p > 0.05). Conclusion: In spite of the fact that amniotic membrane transplantation is less effective than mitomycin C for depressing wound healing after trabeculectomy, it might be a safer alternative in selected cases when considering severe adverse effects of antimetabolites.

Choroidal Thickness Changes During the Menstrual Cycle

Abstract Purpose: To evaluate the effects of the menstrual cycle on the choroidal thickness of healthy women of reproductive age using spectral-domain optical coherence tomography. Materials and methods: A total of 23 right eyes of 23 women with regular natural menstrual cycles of 28–30 d and ages 22–30 years were included in this prospective study. The choroidal thicknesses of the women were measured using high-resolution spectral-domain optical coherence tomography line scans with the activated enhanced depth imaging mode in the early follicular, ovulatory and mid-luteal phases of the menstrual cycle (3rd, 14th and 21st days) using a follow-up scanning protocol of the Spectralis optical coherence tomograph by setting the early follicular phase scan as the reference image. Choroidal thickness measurements were taken at the fovea and at two points that were 1500 µm nasal and temporal to the fovea. The mean arterial pressure, spherical equivalent, intraocular pressure, central corneal thickness and retinal and retinal nerve fiber layer thicknesses were also measured. All measurements were taken within the same menstrual cycle. Results: The mean ± standard deviation (standard error of the mean) of subfoveal choroidal thicknesses in the early follicular, ovulatory and mid-luteal phases were 383.87 ± 84.38 (17.59), 373.74 ± 82.40 (17.18) and 359.09 ± 79.65 (16.61) µm, respectively. The relative reductions in choroidal thickness between early follicular and ovulatory phases and early follicular and mid-luteal phases were 2.64% and 6.47%, respectively. The subfoveal choroidal thickness was decreased significantly in the mid-luteal phase when compared with both the early follicular (p < 0.001) and ovulatory phases (p = 0.003). However, the measures of subfoveal choroidal thickness in the early follicular phase were non-conclusively greater (p = 0.071) than in the ovulatory phase. Additionally, the mean arterial pressure, spherical equivalent, intraocular pressure, central corneal thickness and retinal and retinal nerve fiber layer thicknesses did not significantly differ during the menstrual cycle (p > 0.05 for all). Conclusions: The choroidal thickness decreased significantly in the mid-luteal phase of the menstrual cycle in young, healthy women. These findings emphasize the importance of the menstrual phase in the interpretation of choroidal thickness measurements in women of reproductive age.

Protective effects of pentoxifylline in retinal ischemia/reperfusion injury.

We studied the effect of pentoxifylline on retinal lipid peroxidation and histopathologic changes due to ischemia/reperfusion (I/R). A total of 15 pigmented male guinea pigs were divided into 3 equal groups as control, sham and treatment groups. After application of high intraocular pressure for 90 min for the induction of retinal ischemia, 24-hour reperfusion was established in the sham and treatment groups. In the treatment and sham groups, either 45 mg/kg of pentoxifylline or saline was given 3 times at 8-hour intervals. Biochemical assay and histopathologic evaluation were performed on one randomly selected eye of each animal which was enucleated at the end of the reperfusion period, and retinal malondialdehyde (MDA) levels and thickness of the retinal tissue were determined for each group. The mean MDA level of the sham group was significantly higher versus the control and treatment groups (p < 0.001). When compared with the control group, the mean MDA level of the treatment group was slightly higher, but the difference was not statistically significant (p > 0.05). In comparison with the control group there was a significant increase in the thickness of the retina in the sham group (p < 0.0001), and no significant difference was found in the retinal thickness of the treatment group (p > 0.05). Pentoxifylline might have a preventive effect on the I/R injury of the retina.

Effects of octreotide acetate and amniotic membrane on wound healing in experimental glaucoma surgery

Wound healing affects the success of glaucoma filtering surgery. Antimetabolites and antifibrotic agents are used in the modulation of surgical trauma. This study is performed to evaluate the effects of amniotic membrane and octreotide acetate on wound healing . Thirty pigmented rabbits were divided into three groups each including 10 animals. Trabeculectomy and topical postoperative prednisolone sodium phosphate four times daily for 7 days were applied to one eye of all the rabbits. After trabeculectomy, octreotide 10 μg three times daily applied topically to the octreotide group for 14 days and amniotic membrane transplantation was performed by suturing amniotic membrane between scleral flap and sclera to the amniotic membrane group. The operated eyes of the rabbits were enucleated on the 14th day of the operation and histopathological specimens were obtained from the bleb sites and they were evaluated by light microscope. Fibroblast and macrophage number per cm2 were counted and the average values were calculated. Compared with the control group, the fibroblasts and macrophages significantly decreased in the other two groups (p < 0.0001, p < 0.0001, respectively). The mean number of fibroblasts was lower than those of the control and amniotic membrane groups (p < 0.0001, p < 0.0001, respectively). Similarly the mean macrophage number was significantly lower in the octreotide group versus the control and amniotic membrane groups (p < 0.0001, p < 0.01, respectively). Octreotide administration and amniotic membrane transplantation might be alternative treatments in modulating the wound healing after trabeculectomy.

Pigmented Paravenous Retinochoroidal Atrophy

Seven patients (4 men and 3 women, ranging in age from 27 to 64 years) with pigmented paravenous retinochoroidal atrophy, a rare disorder of unknown origin, were studied. The mean follow-up time was 18.5 months. Fundus examinations were performed, and color fundus photographs were taken. In addition to fluorescein angiography, visual field examinations, color vision and electroretinographic tests were performed. All 7 patients were asymptomatic, with visual acuities ranging from 3/10 to 10/10. Both fundi showed patches of retinochoroidal atrophy and pigmentation along the retinal veins in all patients. Fluorescein angiography showed hyperfluorescence due to the pigment epithelial atrophy together with hypofluorescence corresponding to bone spicule pigment clumping. Visual field tests showed scotomas corresponding with areas of atrophy along the retinal veins. The electroretinography showed reduced responses in 2 cases. Color vision was normal in all cases. The patients had no history of trauma or a previous inflammatory process. Serology for syphilis, Toxoplasma and cytomegalovirus as well as a skin test for tuberculosis were negative. When the patients were seen at the end of the follow-up period, no variation of the findings was noted. Although the fundus abnormalities can be mild or severe, retinal function tests indicated that this is a geographic and not a generalized disorder.

Comparison of the effect of intravitreal bevacizumab and intravitreal fasudil on retinal VEGF, TNFα, and caspase 3 levels in an experimental diabetes model

AIM To evaluate the influence of an intravitreal injection of bevacizumab and fasudil on the retinal vascular endothelial growth factor (VEGF), tumor necrosis factor alpha (TNFα), and caspase 3 levels in a diabetic rabbit model. METHODS The study included 6 healthy rabbits (Group 1), 6 rabbits with experimentally induced diabetes mellitus (DM) (Group 2), 7 rabbits with experimentally induced DM to which intravitreal bevacizumab was administered (Group 3), and 7 rabbits with experimentally induced DM to which intravitreal fasudil was administered (Group 4). An intravitreal injection of 1.25mg/50µL bevacizumab in the right eye of rabbits in Group 3 and an intravitreal injection of 0.0064mg/50µL fasudil in the right eye of rabbits in Group 4 were administered on day 21 after the induction of DM. The studied eyes of the rabbits were enucleated three days after the intravitreal injection. The TNFα, VEGF, and caspase 3 levels were determined using the ELISA method. RESULTS There was a statistically significant difference in the VEGF and caspase 3 levels between groups (P=0.005 and P =0.013, respectively), but the TNFα level did not differ significantly between groups (P=0.792). It was found that VEGF levels were significantly lower in Group 1 and Group 3 than in Group 2 using the Mann-Whitney U test with the Bonferroni correction (P=0.004 for both comparison). There was no statistically significant difference between other groups with regard to VEGF levels (the P value ranged between 0.015 and 0.886). Although the P values of the caspase 3 levels were 0.015 for Group 1 and Group 4, 0.038 for Group 2 and Group 3, and 0.018 for Group 3 and Group 4, these P values remained above the threshold P value of 0.0083, which was the statistically significant level for post hoc tests. CONCLUSION An intravitreal injection of bevacizumab decreased both the VEGF level, which plays a role in angiogenesis, and the caspase 3 level, which plays a role in apoptosis. Although not as effective as bevacizumab, fasudil had a beneficial effect on the VEGF levels but significantly increased the caspase 3 levels.

Effect of Prophylactic Intraocular Pressure-Lowering Medication on Pain During Cataract Surgery

PURPOSE This study evaluated the effects of acetazolamide, latanoprost, travoprost, bimatoprost, brimonidine, brinzolamide, and timolol on pain during phacoemulsification cataract surgery. METHODS This prospective randomized comparative study included 323 eyes of 323 patients with no history of intraocular surgery or chronic eye disease who underwent uncomplicated phacoemulsification cataract surgery and foldable intraocular lens implantation under topical anesthesia. Patients were divided into 8 groups according to the preoperative prophylactic intraocular pressure (IOP)-lowering medication. The intraoperative pain was assessed postoperatively using a visual analog pain scale. The Kruskal-Wallis test investigated the differences in the visual analog pain-scale scores of the groups, and the Mann-Whitney U test investigated the pairwise comparison of the groups. RESULTS The median visual analog pain-scale score of the group that did not receive any IOP-lowering medication was 2.0±1.89. The brimonidine group exhibited the lowest visual analog pain-scale scores, and the prostanoids, especially the bimatoprost group, demonstrated the highest visual analog pain-scale scores (median±standard deviation were 0.0±1.50 and 2.0±1.91, respectively). The median visual analog pain-scale scores of the acetazolamide, latanoprost, travoprost, brinzolamide, and timolol groups were 0.0±1.62, 2.0±1.67, 2.0±1.73, 0.0±1.66, and 1.0±1.54, respectively. A pairwise comparison using the Mann-Whitney U test with Bonferroni correction revealed significant differences between the groups of acetozolamide and travoprost (p=0.001), acetozolamide and bimatoprost (p<0.001), travoprost and brimonidine (p<0.001), bimatoprost and brimonidine (p<0.001), and bimatoprost and timolol (p=0.001). CONCLUSIONS Prophylactic application of the IOP-lowering medication may alter the pain sensation during phacoemulsification cataract surgery.

Dry Eye Syndrome and Allergic Conjunctivitis in the Pediatric Population.

Purpose: To assess the comorbidity of dry eye syndrome (DES) and changes in corneal curvature in children with allergies. Materials and Methods: This prospective, comparative, and observational interventional study included 49 patients, who presented to the Ophthalmology Clinic of a State Hospital in Turkey. There were 25 patients with clinically diagnosed seasonal allergic conjunctivitis (AC) (with complaints of itching and papilla formation of conjunctiva; AC group) and 24 healthy children (control group). There with no significant differences in age between groups. Using the ocular surface disease index (OSDI) questionnaire, we performed tear film break-up time (BUT), central reflex tear meniscus height (TMH-R) measurement, Schirmer test on both groups and evaluated keratometry (K1, K2) and spherical equivalent (SE). Results: Patients ranged in age from 6 to 18 years (median age, 11.79 years; 46.9% male; 53.1% female). The papillary reaction was severe in 10% of patients with AC. The prevalence of dry eye in children with AC was 12%. There was no statistically significant difference between groups for K1, K2, and SE (P > 0.05, all comparisons). BUT was statistically different (P = 0.004) between groups, indicating that a higher OSDI the tear film BUT was lower (ρ = 0.567). Statistically, significant negative moderate correlations were found between papillary reaction and the Schirmer test, BUT, and TMH.R (ρ = 0.454, −0.412, −0.419, and P = 0.001, 0.003, 0.002, respectively) Conclusions: The evaluation of pediatric patients with AC requires further attention to ensure an adequate diagnosis of DES.

Effects of a Water-loading Test on Intraocular Pressure and Corneal Hysteresis in Young Healthy Subjects

Purpose:To evaluate the influence of a water-loading test on corneal compensated intraocular pressure (IOPcc) and corneal hysteresis (CH) in young healthy subjects. Materials and Methods:Forty healthy adult subjects (20 female and 20 male), with a mean age of 27.55±2.57 years (range, 24 to 35 y), participated in this prospective study. IOPcc and CH were measured for 1 eye from each participant with an Ocular Response Analyser. These measurements were taken before and 10, 20, and 30 minutes after water loading. Results:Thirty-seven right and 3 left eyes of the 40 subjects fulfilled the study’s inclusion criteria. A statistically significant increase in IOPcc was observed between 0 and 10 minutes (P=0.002) and a significant decrease between 10 and 30 minutes (P<0.001). We did not observe any statistically significant changes in CH. The Pearson correlation revealed that there was a weak negative correlation between IOPcc and CH measurements taken at the baseline, 10 minutes, and 30 minutes [r values were −0.275 (P=0.086), −0.369 (P=0.019), and −0.246 (P=0.125), respectively]. Conclusions:This study revealed changes in IOPcc and CH after a water-loading test, but only the change in the IOPcc measurement was statistically significant. The association of changes in IOP and CH identified in this study suggests that IOP changes might alter corneal biomechanical properties.