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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.

Systematic, combined treatment approach to nasolacrimal duct obstruction in different age groups

Purpose To report the outcome of a step-by-step treatment approach for congenital nasolacrimal duct obstruction (CNDO). Methods Three-hundred and fifty eyes with CNDO were included in the study. A number of treatment methods were applied systematically until a successful outcome was achieved. Listed in order from simple to more complex, the following methods were used: conservative management (massage and topical antibiotics), high-pressure syringing, probing, and silicone intubation. Treatment efficacy was determined according to age (Group 1: 0–6 months, Group 2: 7–12 months, Group 3: 13–24 months, Group 4: 25–72 months) and success rates were compared. Results Conservative management was applied only in children less than 1 year of age, and was successful in 91.8% of Group 1 and 60% of Group 2 eyes. The difference between these two success rates was significant (p = 0.003). High-pressure syringing was performed in children under 24 months of age, with success rates of 41.7% in Group 1, 33.3% in Group 2, and 12.5% in Group 3. The overall success rate for first probing in all groups was 76.1%, with a range of 69.4% to 80.9%. After second probing, the overall cure rate for the entire cohort was 88.0%, with a range of 74.9% to 94.8%. There was no real difference in probing cure rates relative to age (p > 0.05). Silicone intubation was indicated and performed in two eyes of Group 2 children, three eyes of Group 3, and nine eyes of Group 4. Two ducts in Group 4 eyes remained obstructed after silicone intubation. Conclusions The systematic treatment approach to CNDO, including conservative management and minimally invasive procedures such as high-pressure syringing, probing, and silicone intubation, is highly successful. In this study, the cure rate for this combined approach was 100% in youngsters under 2 years of age and 94.5% in children 2 to 6 years old.

Comparison of tear function tests and impression cytology with the ocular findings in acne rosacea.

Purpose The aim of this study was to determine the correlation between tear function tests and impression cytology results and the clinical findings in ocular rosacea. Methods Patients with a histopathologic and clinical diagnosis of acne rosacea were studied. Ocular examination consisted of best-corrected visual acuity measurement, slitlamp examination, tear break-up time (BUT), basal Schirmer test, and rose Bengal staining. Impression cytology was done two days later. Ocular findings and symptoms were checked and scored. Age-matched controls were assessed using the same parameters. Results The most frequent symptoms were itching (80%), redness (68%), burning (64%), and photophobia (60%). The most frequent clinical findings were meibomitis (92%), telangiectasis (88%), blepharitis (84%), superficial punctate keratopathy (72%), and hyperemia (60%). Mean tear BUT was 9.6 ± 3.1 (SD) seconds (range 5–17 seconds). Mean Schirmer test measured 11.4 ± 1.6 mm (SD) (range 8–15 mm). Mean rose Bengal staining scored 1.8 ± 0.1. Mean tear BUT, Schirmer test and rose Bengal staining scores were lower in the rosacea group than the control group (p<0.003, p=0.04, p≤0.038, respectively). Staining was pathologic in 18 patients (36%) and the highest staining score was 4. No significant difference was found between the stages of the nasal and temporal conjunctival impression cytologies in each eye, and there was no relationship between impression cytology stages and rose Bengal scores (p>0.05). A significant relation was observed between the stages of impression cytology and the severity of meibomitis (Fishers test, χ2=9.625, p=0.001). The Schirmer test gave lower results in patients with severe blepharitis (Mann-Whitney U Test, U=180.5, p=0.034). Conclusions Early diagnosis prevents serious ocular complications and chronic dry eye in rosacea. We suggest that in addition to tear function tests, rose Bengal staining and impression cytology can be successfully used in the early diagnosis of dry eye and in monitoring medical treatment in ocular rosacea. Meibomian glands play an important role in the pathogenesis of the ocular disease.

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.

Efficacy and Safety of Rimexolone 1% Versus Prednisolone Acetate 1% in the Control of Postoperative Inflammation Following Phacoemulsification Cataract Surgery

Purpose: The aim of this study was to evaluate the efficacy and safety ofrimexolone 1% ophthalmic suspension compared to that of 1% prednisoloneacetate in the control of inflammation in eyes undergoing cataract extraction withphacoemulsification followed by posterior chamber intraocular lens implantation.Methods: Forty-eight patients who underwent uncomplicated cataract extraction with phacoemulsification followed by posterior chamber IOL implantation constituted the study group of this prospective, randomized, double-masked investigation. Patients were randomly assigned to two treatment groups; rimexolone 1% ophthalmic suspension (27 subjects) or prednisolone acetate 1% (21 subjects). Postoperatively, patients used topical rimexolone or prednisolone drops four times a day for 15 days. Patients were examined at the first postoperative day (day 1), and days 3, 7 and 15. The major efficacy parameters assessed clinically on each visit were anterior chamber cells, anterior chamber flare and conjunctival hyperemia. Safety of the rimexolone was evaluated by IOP values and the presence of adverse effects.Results: Regarding all three efficacy parameters, rimexolone was found to be clinically and statistically equivalent to prednisolone acetate. Intraocular pressure values during the postoperative period were also similar in both groups.Conclusion: Rimexolone 1% ophthalmic suspension is both an effective and safe topical steroid in controlling postoperative inflammation after cataract extraction with phacoemulsification.

Protective effect of ischemic preconditioning on retinal ischemia-reperfusion injury in rats

BACKGROUND A short period of ischemia can induce remarkable tissue resistance to the deleterious effects of subsequent ischemia and reperfusion. We performed a study to investigate the effect of ischemic preconditioning on retinal ischemia-reperfusion injury in rats. METHODS Ten Wistar albino rats were divided into two groups of five animals (10 eyes): one group underwent 5 minutes of ischemic preconditioning (achieved by clamping the common carotid arteries at the time of vertebral artery cauterization), and the other did not (control group). In both groups, the vertebral arteries were occluded bilaterally with an electric needle coagulator under an operating microscope. Forty-eight hours later the rats were reanesthesized, and both common carotid arteries were clamped to interrupt blood flow. The duration of ischemia was 30 minutes. The clamp was then removed to enable reperfusion for 4 hours. The animals were killed by decapitation, and retinal sections were evaluated under light and electron microscopy. The signs of ischemia-reperfusion injury (cellular degeneration, vacuolization between retinal layers, increase in retinal thickness due to edema, mononuclear cell infiltration and apoptotic cell count) were recorded. RESULTS Light microscopy of retinal sections from rats in the ischemic preconditioning group showed a well-preserved retinal structure. The mean thickness values (and standard deviation [SD]) for the inner nuclear layer (104.0 microm [2.54 microm] vs. 49.0 microm [ 10.83 microm]) and inner plexiform layer (134.8 microm [10.13 microm] vs. 88.5 microm [17.46 microm]) were significantly higher in the control group than in the preconditioning group (p = 0.009), indicating increased retinal thickness in the former group due to tissue edema resulting from ischemia-reperfusion injury. The mean mononuclear cell count (6.67 [SD 1.97] vs. 2.5 [SD 1.0]) and apoptotic cell count (18.2 [SD 5.7] vs. 5.3 [SD 1.0]) were significantly higher in the control group than in the preconditioning group (p = 0.002), indicating an inhibitory effect of ischemic preconditioning on leukocyte infiltration and apoptotic cell death. INTERPRETATION Ischemic preconditioning attenuated ischemia-reperfusion injury in the rat retina.

A combination of topographic and pachymetric parameters in keratoconus diagnosis

PURPOSE To evaluate the utility of topographic and pachymetric parameters of Scheimpflug system in keratoconus diagnosis. METHODS This study included 183 eyes of 183 patients with keratoconus (keratoconus group) and 131 eyes of 131 age and sex-matched healthy subjects (control group). Mean keratometry (K, front), topographic astigmatism, pupil-center pachymetry, apical pachymetry, thinnest pachymetry (TP), corneal volume and maximum K (Kmax) were obtained from the Scheimpflug imaging system. A receiver operating characteristic (ROC) analysis was performed and area under the curve (AUC) was calculated to determine the diagnostic ability of each parameter in eyes with ≤ stage 3, ≤ stage 2 and stage 1 keratoconus based on the Amsler-Krumeich grading system. RESULTS The Kmax and TP showed the highest individual performance (with sensitivity-specificity of 92.9-92.4% and 89.6-93.3%, respectively) in diagnosis of keratoconus. The AUCs and sensitivity-specificity values for the Kmax/TP and Kmax(2)/TP were calculated to improve the diagnostic performance. As expected, sensitivity-specificity values significantly increased by using Kmax/TP (97.3-94.7% at the level ≥0.08) and Kmax(2)/TP (99.5-95.7% at the level ≥4.1) in discrimination of keratoconic eyes from normals. Moreover, Kmax(2)/TP had very high sensitivity (>99%) and specificity (>94%) in diagnosis of stage 1 and stage 2 keratoconus. CONCLUSIONS Although Kmax and TP appear to have high diagnostic ability in keratoconus, the use of either single parameter in isolation might be unsatisfactory in differential diagnosis. Therefore, the Kmax(2)/TP ratio has been introduced, which reflects major characteristics of keratoconus and might be used as an important criterion in keratoconus diagnosis.