Cem Yildirim

Assessment of central and peripheral fusion and near and distance stereoacuity in intermittent exotropic patients before and after strabismus surgery

PURPOSE To determine whether central fusion and distance stereoacuity are useful as objective measures in assessing the need for and success of surgery for intermittent exotropia (X[T]). METHODS A prospective, institutional, clinical trial was conducted of 26 consecutive patients with X(T) who were undergoing strabismus surgery in whom fusion (central and peripheral) and stereoacuity (at near and distance) were assessed preoperatively and postoperatively, as well as in 112 normal subjects. To obtain accurate measurements with sensory tests, the lower age was limited to 5 years for inclusion. A successful surgical alignment was defined as an exotropia of 10 prism diopters or less at 6 m. Sensory and motor outcome measures were determined 1 year after surgery. RESULTS The successful surgical alignment rate was 69%. All patients with X(T) demonstrated peripheral fusion, whereas 35% demonstrated central suppression preoperatively and postoperatively. Central fusion was not predictive of surgical outcome (P = .078); however, there was a trend toward less surgical success in patients with central suppression. Patients with X(T) exhibited good near stereoacuity before and after surgery. Distance stereoacuity in patients with X(T) preoperatively was significantly diminished compared with normal subjects (P < .001) and was improved in 58% postoperatively. Patients who achieved successful surgical alignment had a greater likelihood of demonstrating distance stereoacuity improvement postoperatively than patients who failed to achieve successful surgical alignment (P = .003). Patients with central suppression were unlikely to improve their distance stereoacuity postoperatively (P = .014). CONCLUSIONS Successful surgery may improve distance stereoacuity. Better distance stereoacuity and central fusion are frequently associated with better surgical success in X(T).

Basal serum nitric oxide levels in patients with type 2 diabetes mellitus and different stages of retinopathy

PURPOSE To compare the basal serum levels of nitric oxide (NO) in patients with type 2 diabetes mellitus and different stages of diabetic retinopathy (DR) with the levels in nondiabetic control subjects. METHODS The 39 patients with type 2 diabetes included in this study were divided by stage of DR into 3 groups: group A, those without DR; group B, those with background/preproliferative DR; and group C, those with proliferative DR. Eleven nondiabetic subjects made up the control group (group D). The NO concentration was determined indirectly by measuring the serum level of nitrite (NO2-) plus nitrate (NO3-) (NOx = NO2- plus NO3-) using a spectrophotometric method based on the Griess reaction. RESULTS The patients with type 2 diabetes had significantly higher levels of serum NOx than the nondiabetic controls (p = 0.0001). In addition, the levels in the patients with proliferative DR were significantly higher (p = 0.002) than the levels in the patients with nonproliferative or no DR. CONCLUSION Our study demonstrated both elevated levels of serum NOx in diabetic patients as compared with nondiabetic controls and a relationship between NOx and DR severity. Hence, abnormal NO metabolism may have a role in the pathogenesis of DR.

Hyperhomocysteinemia: A Risk Factor for Retinal Vein Occlusion

Purpose: The aim of the study was to investigate the plasma homocysteine levels in patients with retinal vein occlusion (RVO) in order to reveal whether hyperhomocysteinemia was a risk factor for RVO. Methods: Thirty-three consecutive patients diagnosed to have RVO of any type and 25 age- and sex-matched controls without RVO were included in this prospective case-control study. Data regarding age, sex, history of hypertension, diabetes mellitus, other vascular events, glaucoma, medications and smoking habits were obtained from all subjects. Several laboratory tests relating to vascular disease including cholesterol, triglyceride and hematocrit were checked. The plasma total homocysteine (tHcy) level was measured by high-performance liquid chromatography (normal range: 5–15 µmol/l). Plasma folate, vitamin B12 and creatinine levels were also studied since these vitamins and impairment of renal function might affect plasma tHcy values. Results: Patients with RVO had a significantly higher tHcy level (median: 11.7 µmol/l, range: 7.2–25 µmol/l) compared to controls (median: 10.3 µmol/l, range: 6.7–13.4 µmol/l; p = 0.005). Nine of 33 patients with RVO (27.3%) had an elevated plasma tHcy level, whereas none of the controls had an abnormal tHcy value (p = 0.004). Plasma folate, vitamin B12 and creatinine levels were comparable between the two groups (p > 0.05). Conclusions: The present study suggests an association between hyperhomocysteinemia and RVO. Further controlled studies with a large number of cases are needed to investigate the exact role of hyperhomocysteinemia in RVO.

Distance Stereoacuity Norms for the Mentor B-VAT II-SG Video Acuity Tester in Young Children and Young Adults

PURPOSE The purpose of this study was to provide normative distance stereoacuity data for the Mentor B-VAT II-SG video acuity tester (Mentor O & O, Norwell, Mass.). METHODS Near and distance stereoacuity for 45 normal young children (5 to 6 years old, child group) and 67 normal young adults (16 to 20 years old, adult group) were evaluated. Distance stereoacuity was measured with the Random Dot and the Circles tests on the B-VAT unit. Near stereopsis was assessed by Titmus, Randot, and TNO tests. Additionally, a random subset of the subjects was retested 1 month later with the B-VAT unit. RESULTS The mean and SD values of stereoacuity measured on the Circles and Random Dot tests were 49 +/- 33 and 98 +/- 49 seconds of arc in children (p < 0.0001) and 50 +/- 32 and 83 +/- 51 seconds of arc in adults (p < 0.0001), respectively. No significant differences were found between the same tests with respect to age. Of 112 subjects in both groups, 110 (98%) achieved 120 seconds of arc or finer stereoacuity threshold levels on the Circles test and 108 (96%) demonstrated 180 seconds of arc or finer scores on the Random Dot test. Although all but two of the subjects exhibited stereopsis both at near and at distance, there were low correlations among the different near and distance stereotests. Test and retest distance stereoacuity scores agreed closely. CONCLUSIONS The B-VAT II-SG system produces reliable distance stereoacuity data. The norms we obtained may aid the clinician to detect binocular visual disturbances or may provide a basis for using distance stereoacuity as a screening method.

Effect of Trimetazidine on Retinal Ischemia/Reperfusion Injury in Rats

Purpose: To investigate the effect of trimetazidine (TMZ), an antioxidant agent, on the ischemia/reperfusion (I/R) injury in rat retina histopathologically. Methods: The retinal I/R model was carried out by the 4-vessel occlusion method on Wistar albino rats. Twenty-one rats were divided into 7 groups, each comprising 3 rats. The animals in groups 1, 2 and 3 underwent 30 min of ischemia + 4 h of reperfusion and were treated by the administration of saline, TMZ before reperfusion and TMZ before ischemia, respectively. The animals in groups 4, 5 and 6 underwent 90 min of ischemia + 4 h of reperfusion and were treated in the same way as those in groups 1, 2 and 3, respectively. The 7th group was sham operated. Results: Thirty and 90 min of ischemia followed by 4 h of reperfusion induced retinal injury in the rat retina. Histopathologically, the inner plexiform and inner nuclear layers were the most affected parts. TMZ was able to reduce almost all retinal I/R damage when administered before ischemia. A cytoprotective effect of TMZ was partly observed in those animals which were treated before reperfusion. Conclusion: TMZ seemed to have a protective effect against retinal I/R injury in rats.

Orbital color Doppler imaging in Behçet’s disease with or without ocular involvement

PurposeTo investigate the value of color Doppler imaging (CDI) of orbital vasculature in the assessment of ocular involvement in patients with Behçet’s disease (BD) without clinical ophthalmologic abnormalities.MethodsCDI of the orbital vessels were performed on 26 eyes of 13 patients who were diagnosed as having BD with ocular involvement (group 1), 65 eyes of 33 patients who had BD without ocular involvement (group 2) and 40 eyes of 20 healthy volunteers (group 3). Peak systolic (PSV) and end-diastolic (EDV) blood flow velocities and resistivity index (RI) measurements were obtained for the ophthalmic artery (OA) and central retinal artery (CRA). The mean velocity of the central retinal vein (CRV) was also measured.ResultsFor the OA, PSV and EDVs were significantly lower and RIs were significantly higher in group 2 than in control subjects. In group 1, only the EDVs of OA were significantly lower than in healthy subjects. For the CRA, PSV and EDVs were significantly lower, and RIs were significantly higher in both BD groups than those in group 3. When group 1 and group 2 were compared, the differences between PSV, EDV and RI measurements for the CRA and OA were statistically insignificant. There was no significant difference in blood flow velocity of the CRV between the three groups.ConclusionMajor hemodynamic changes were observed in the ophthalmic vasculature of Behçet’s patients with or without ocular involvement by CDI. CDI may detect ocular blood flow alterations before initial clinical manifestations.

Effects of intraoperative sponge mitomycin C and 5-fluorouracil on scar formation following strabismus surgery in rabbits

purpose To investigate the influence of 5-fluorouracil (5-FU) and mitomycin C (MMC) on the postoperative adhesions following strabismus surgery in rabbits. methods Twenty-one New Zealand white rabbits were used in this prospective, masked, controlled trial. Both eyes of 20 animals underwent 3-mm recession of the superior rectus muscle (SRM). In group I (10 animals), one eye of each animal received topical application of MMC (0.2 mg/ml) for 5 minutes and the other eye (control eye) was treated with balanced salt solution (BSS) using an intraoperative sponge. In group II (10 animals), a randomly chosen eye of each animal was treated with 5-FU soaked sponges (50 mg/ml) for 5 minutes and the fellow eye (control eye) with BSS. Two eyes of a rabbit were included as unoperated controls. Four weeks after the surgery, conjunctival vascularity and postoperative adhesions between the SRM Tenons capsule (TC) and SRM sclera (scl) were assessed. Additionally, eyes were enucleated and evaluated histopathologically for evidence of scarring, granuloma formation, and muscle tissue changes under a light microscope. results MMC-treated eyes had a higher rate of avascular conjunctiva compared to both controls and 5-FU-treated eyes. Mean adhesion scores, particularly between the SRM-scl, were lower in eyes treated with antiproliferative agents compared to controls. The difference was statistically significant in MMC-treated eyes for the adhesions between SRM-scl (p = 0.03). Histopathological examination revealed less scarring and granuloma formation in MMC- and 5-FU-treated eyes compared to their control eyes. conclusions MMC, and to a lesser extent 5-FU, are shown to be effective in reducing postoperative scarring following strabismus surgery in rabbits. It seems reasonable to suggest that antimetabolites should be used for cases having an increased risk of postoperative adhesions.

Subjective Visual Experience and Pain Level during Phacoemulsification and Intraocular Lens Implantation under Topical Anesthesia

Purpose: To investigate the subjective visual experiences and pain during the phacoemulsification and intraocular lens (IOL) implantation under topical anesthesia, and whether these parameters change according to the stage of phacoemulsification cataract surgery. Methods: Forty eyes of 40 patients with cataract undergoing phacoemulsification and IOL implantation under topical anesthesia were included in this study. The patients were told that they would be asked about their visual experiences and pain level, if any, during every stage of the surgery. As for degree of the pain, a 5-grade scale was used. The surgery was divided into 9 stages, i.e., clear corneal incision, continuous curvilinear capsulorhexis, side-port incisions at 3 and 9 o’clock positions, hydrodissection, nuclear rotation, phacoemulsification, bimanual irrigation and aspiration, IOL implantation, apposition of corneal incisions with stromal hydration. Results: All subjects (100%) reported that they had seen some kind of light during the operation. Thirty-eight patients (95%) said that they had seen one or more colors. In 32 patients (80%), the light intensity decreased, and colors blurred significantly following the hydrodissection. As for the pain level during surgery, the overall pain score was found to be 0.40. The highest mean pain score was noted during IOL implantation stage followed by phacoemulsification and bimanual irrigation-aspiration. Conclusion: Topical anesthesia is both a safe and effective method for small-incision clear corneal phacoemulsification cataract surgery. Patients may experience visual sensations, and the pain felt during the operation is low and tolerable. Visual experiences and pain level may change according to the stage of phacoemulsification cataract surgery.

Expanding the phenotypic spectrum of ECEL1-related congenital contracture syndromes.

Using a combination of homozygosity mapping and whole‐exome sequencing (WES), we identified a novel missense c.1819G>A mutation (G607S) in the endothelin‐converting enzyme‐like 1 (ECEL1) gene in a consanguineous pedigree of Turkish origin presenting with a syndrome of camptodactyly, scoliosis, limited knee flexion, significant refractive errors and ophthalmoplegia. ECEL1 mutations were recently reported to cause recessive forms of distal arthrogryposis. This report expands on the molecular basis and the phenotypic spectrum of ECEL1‐associated congenital contracture syndromes.

Association of serum lipid levels with diabetic retinopathy.

AIM To assess the association between serum lipids and diabetic retinopathy (DR). METHODS Sixty-one diabetic patients without retinopathy(NDR), 55 diabetic patients with non-proliferative retinopathy(NPDR) and 75 diabetic patients with proliferative retinopathy (PDR) according to ETDRS grading scale were enrolled in this study. Total cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), very low density lipoprotein (VLDL) and triglyceride values were compared between the groups. RESULTS The groups were well-balanced in terms of age and gender (P=0.071, P=0.265 respectively). The mean HbA1c values were significantly lower in NDR group than the NPDR and PDR groups (P=0.004, P=0.009 respectively). Mean total cholesterol, triglyceride, LDL, HDL and VLDL levels were not significantly different between the groups (P=0.693, P=0.774, P=0.644, P=0.910 and P=0.967 respectively, one way ANOVA). Mean total cholesterol, triglyceride, LDL, HDL and VLDL levels were not significantly different between the patients with ME and patients without ME (P=0.622, P=0.113, P=0.955, P=0.735 and P=0.490 respectively, t-test). The mean blood glucose significantly correlated with total cholesterol (r=0.173, P=0.017) and LDL (r=0.190, P=0.008). The mean HbA1c significantly correlated with total cholesterol (r=0.158, P=0.030) and triglyceride (r=0.148, P=0.042). CONCLUSION Serum lipid levels were not significantly associated with the severity of DR or existence of ME despite the significant correlation between the mean blood glucose, HbA1c and total cholesterol.