Investigation of dynamic thiol-disulphide homoeostasis in age-related cataract patients with a novel and automated assay.

PURPOSE: The aim of this study was to determine plasma thiol-disulphide homoeostasis in patients with age-related cataract (ARC) and compare the results of the patients with healthy subjects. Plasma malondialdehyde (MDA) levels and catalase (CAT) activity were also investigated. METHODS: The study included 53 cataract patients and 52 healthy volunteers. Native thiol-disulphide exchanges were determined using a novel and automated method. CAT activity was determined using the method described by Aebi, and MDA levels were calculated using the thiobarbituric acid method. RESULT: Native thiol and total thiol levels were significantly lower in the cataract patients compared with the controls (p < 0.001, p = 0.002, respectively). The disulphide levels of the cataract patients were significantly higher than the controls (p = 0.002). The ratios of disulphide/native thiol and disulphide/total thiol were statistically higher in the cataract patients compared with the control group (p < 0.001, p < 0.001, respectively). Furthermore, CAT activity was significantly lower in the cataract patient group compared with the control group (p < 0.001), and MDA levels were insignificantly higher in the patient group (p = 0.581). CONCLUSIONS: Our study showed that dynamic thiol-disulphide homoeostasis has shifted towards disulphide formation, as a result of thiol oxidation in ARC patients. The present study is the first to measure thiol-disulphide homoeostasis in ARC patients with a novel automated assay. This study supports the hypothesis that cataract is an oxidative disorder. Further studies are required in order to examine the relationship between oxidative stress and the development of cataract formation.

Retrospective analysis of the effect of aflibercept loading dose on the retinal vessel diameters in patients with treatment-naive neovascular AMD.

BACKGROUND: To evaluate the effects of intravitreal aflibercept (IVA) on retinal vessel diameters in patients with neovascular age-related macular degeneration (AMD). DESIGN, SETTING, AND PARTICIPANTS: A retrospective study conducted at the Kutahya Dumlupinar University Faculty of Medicine included 15 eyes of 15 patients with treatment naive neovascular AMD. METHODS: All eyes received IVA injections once per month for 3 months; untreated contralateral eyes were used as controls. The central retinal artery equivalent (CRAE), central retinal vein equivalent (CRVE), and artery-vein ratio (AVR) values were measured using a computer-based program before the first IVA injection and 30 days after the first, second, and third injections. The main outcome measurements were the central macular thickness (CMT), best-corrected visual acuity (BCVA), choroidal thickness, CRAE, CRVE, and AVR. RESULTS: Significant vasoconstriction of the retinal arterioles was observed in all eyes treated with IVA when compared to baseline (p = 0.009). However, no significant differences were found for CRVE or AVR throughout the study period in treated eyes. In the control group, all parameters measured during each visit were similar to baseline measurements (p > 0.05). The mean BCVA significantly improved at the end of the loading dose of IVA, when compared to baseline (p = 0.006). After the IVA injections, the mean CMT and choroidal thickness were significantly reduced at all visits, compared to baseline (p < 0.001). CONCLUSIONS: The current study showed that IVA led to significant retinal arteriolar vasoconstriction and choroidal thinning, which may cause reduced retinal blood flow.

VEGF-A gene polymorphisms and responses to intravitreal ranibizumab treatment in patients with diabetic macular edema.

PURPOSE: To investigate the association between VEGF gene polymorphisms and the responses to treatment with intravitreal ranibizumab (IVR) in patients with diabetic macular edema (DME). METHODS: This prospective study, conducted at the Kutahya Dumlupinar University Faculty of Medicine, included 95 patients with DME that were treated with IVR and 32 patients without DME despite proliferative diabetic retinopathy (PDR). The participants were divided into three groups: DME with non-proliferative diabetic retinopathy, DME with PDR, and PDR without DME; patients with DME who were treated with IVR were further divided into two groups based on their response to the treatment. Each patient was genotyped for five single nucleotide variations (SNVs) in VEGF-A: rs2010963, rs2146323, rs10434, rs833069, and rs6921438. RESULT: There was a statistically significant difference in allelic distribution of VEGF-A rs833069 polymorphism in relation to the severity of diabetic retinopathy (DRP) (p = 0.031). The allelic distribution of VEGF-A rs2146323 polymorphism tended to be associated with the severity of DRP (p = 0.069). There were no statistically significant differences in the allelic distribution of the studied five SNVs in DME patients regarding the patients' responses to IVR therapy. CONCLUSIONS: There is no association between the studied VEGF-A SNVs and the responses to IVR therapy in DME. However, the VEGF-A rs833069 gene polymorphism has a clear association with the severity of diabetic retinopathy.

Dynamic thiol/disulfide homeostasis in patients with age-related macular degeneration.

PURPOSE:: We evaluated dynamic thiol/disulfide homeostasis (TDH), malondialdehyde (MDA) levels, and catalase (CAT) activity in patients with age-related macular degeneration (AMD). All analyzes were conducted on plasma samples. METHODS:: Thirty-two patients with AMD and 38 age-matched healthy controls were included. Native thiol, total thiol, and disulfide levels and TDH status were determined using a novel, automated assay. MDA levels and CAT activity were determined. Percentages were compared using the chi-squared test. The Student's t-test and Mann-Whitney U-test were used to compare quantitative variables. RESULTS:: Native thiol levels were significantly lower (p=0.004) in patients with AMD (272.02 ± 52.41 µmol/l) than in healthy individuals (307.82 ± 47.18 µmol/l), whereas disulfide levels were significantly higher (p<0.001) in patients with AMD than in controls (21.64 ± 5.59 vs. 14.48 ± 5.37 µmol/L). Dynamic TDH was also significantly lower (p<0.001) in patients with AMD than in controls (13.41 ± 4.3 vs. 25.41 ± 14.52 µmol/l). No significant differences were evident in total thiol or MDA levels. Mean CAT activity was significantly higher (p=0.043) in patients with AMD compared with controls (0.035 vs. 0.018 k/ml). CONCLUSIONS:: The antioxidant/oxidant balance demonstrated by dynamic TDH is shifted to the oxidative side in patients with AMD.

Impact of Smoking on the Ocular Surface, Tear Function, and Tear Osmolarity.

PURPOSE: This study evaluated the effects of cigarette smoking on the ocular surface, tear function, and tear osmolarity. MATERIALS AND METHODS: A total of 50 smokers with at least 5 years of heavy smoking (defined as 1 pack/day) and 51 nonsmoking, healthy individuals were enrolled. Tear osmolarity was measured with an osmometer (TearLab™ Osmolarity System). Ocular surface examinations involved corneal fluorescein staining, measurement of the tear film breakup time (TBUT), the Schirmer 1 test, measurement of corneal sensitivity with a Cochet-Bonnet esthesiometer, and conjunctival impression cytology. Dry eye symptoms were scored using the Ocular Surface Disease Index (OSDI) questionnaire. The results were compared with those from an age and sex-matched control group. The Chi-squared and independent sample t-tests were used for statistical analyses. RESULTS: The smokers had significantly higher tear osmolarity values (305.38 ± 9.81 vs. 301.14 ± 7.04 mOsm/L; p = 0.014) and OSDI scores (34.13 ± 16.58 vs. 18.09 ± 9.61; p < 0.001) than the healthy controls. However, the TBUT, corneal sensitivity, and goblet cell density were significantly lower in smokers compared to healthy controls, but the fluorescein staining and Schirmer 1 test results were not statistically different between the smokers and controls. CONCLUSION: Smoking results in increased osmolarity of the tear film, which can damage the ocular surface and tear function.

Thiol Disulfide Homeostasis in Pseudoexfoliation Syndrome.

PURPOSE: To determine the serum thiol disulfide homeostasis in patients with pseudoexfoliation (PEX) syndrome. METHOD: Thirty-five patients with PEX syndrome and forty healthy subjects were included in this observational case-control study. Serum native thiol, total thiol, disulfide, and native thiol/disulfide ratio were determined using a novel and automated assay. RESULTS: The mean serum total thiol and native thiol levels were significantly lower in patients with PEX syndrome compared to healthy controls (p = 0.001). The mean serum disulfide level was significantly higher in patients with PEX syndrome compared to healthy controls (p = 0.023). The serum native thiol/disulfide ratio was lower in patients with PEX syndrome compared to healthy subjects (16 ± 10.1 vs 22.3 ± 11.5, respectively, p = 0.014). CONCLUSION: Our findings provide evidence that the dynamic native thiol/disulfide ratio is lower in PEX syndrome, which shows a reduction in the natural cell reductive capacity reservoir.

Mean Platelet Volume is Associated with Diabetic Macular Edema in Patients with Type-2 Diabetes Mellitus.

AIM: To evaluate the effect of the platelet indices on the stage of diabetic retinopathy (DR) and diabetic macular edema (DME). METHODS: In this retrospective study, the mean platelet valume (MPV), Plateletcrit (PCT), platelet (PLT), and platelet distribution width (PDW) of 199 diabetic patients and 76 healthy subjects were enrolled. The participants were divided into four groups. The first group was healthy control; the second group consisted of diabetic patients without DR; the third group was nonproliferative DR (NPDR); and the fourth group was proliferative DR (PDR). RESULTS: Significant differences were found only in MPV and PCT values between patients with diabetes and healthy participants (8.6±0.96 fL vs 8.32±0.9 fL, P=0.011, 0.216± 0.58 vs 0.202±0.52, P=0.038). Comparing the groups, a statistically significant difference in MPV values was found between groups 4 and 1 (8.91±.7 fL vs 8.32±0.9 fL P=0.001) and between groups 4 and 3 (8.91±.7 fL vs 8.42±0.9 fL P=0.014). The MPV values of patients with DME were significantly higher than those of diabetic patients without DME (8.87±0.80 fL vs 8.45±0.97 fL). CONCLUSION: High MPV values may be an important risk factor for the development of PDR and DME in patients with diabetic retinopathy.

Unilateral hemorrhagic macular infarction associated with marijuana, alcohol and antiepileptic drug intake.

A 55-year-old male presented with a complaint of a painless and sudden loss of vision in the right eye. Fundus photography revealed loss of transparency and edema in the central macular region. Optical coherence tomography showed increased reflectivity and diffused swelling in the inner retinal layers. Fluorescein angiography revealed a large area of capillary non-perfusion with a pronounced hypofluorescent area with distinct borders. To our knowledge, this is the first report of a hemorrhagic macular infarction associated with marijuana and pregabalin misuse.

Central corneal thickness and corneal curvature in patients with rheumatoid arthritis.

The aims of this study were to determine the central corneal thickness (CCT) and corneal curvature (CC) in patients with rheumatoid arthritis (RA), and to evaluate the correlations between the CCT, CC, RA activity, and RA duration. Fifty-four RA patients (104 eyes; 35 with dry eye, 69 without dry eye) and 21 age- and gender-matched control patients (42 eyes) were enrolled in the study. The CCT and CC were measured by ultrasonic pachymeter and autorefractor-keratometer, respectively. RA activity was assessed using the disease activity score (DAS) 28. The independent samples' t test and Pearson correlation analysis were used in the statistical analyses. Mean CCTs were found to be 535.88 ± 38.24, 530.46 ± 32.88, 538.64 ± 40.64, and 543.40 ± 40.66 µm in all RA eyes, RA with dry eyes, RA without dry eyes, and control eyes, respectively. Mean keratometry (K) readings were found to be 43.84 ± 1.76, 43.73 ± 1.23, 43.90 ± 1.98, and 43.60 ± 1.48 D in all RA eyes, RA with dry eyes, RA without dry eyes, and control eyes, respectively. There were no significant differences in CCT values (p values, 0.293, 0.134, and 0.550, respectively) and K readings (p values, 0.435, 0.681, and 0.402, respectively) between the RA and control eyes. These findings led us to the conclusion that the CCT and K readings were not significantly associated with DAS (p values, 0.678 and 0.812, respectively) and RA duration (p values, 0.108 and 0.080, respectively). Our results show that CCTs and CCs were not significantly different between the RA eyes and control eyes. CCTs and CCs were also not associated with RA activity and RA duration.

Evaluation of the Choroid, Fovea, and Retinal Nerve Fiber Layer in Patients with Rheumatoid Arthritis.

PURPOSE: To evaluate the effect of rheumatoid arthritis (RA) on choroid, retinal nerve fiber layer (RNFL), and foveal thickness using spectral domain optical coherence tomography (OCT). METHODS: Fifty patients with RA and forty-one healthy volunteers were enrolled in this study. The subfoveal, perifoveal choroidal, RNFL, and foveal thicknesses were measured by spectral domain OCT. RESULTS: The mean subfoveal, nasal, and temporal choroidal thicknesses in RA individuals were significantly higher than those in the control group (p ˂ 0.05). However, there was no significant difference between the RA and healthy group regarding RNFL and foveal thickness (p ˃ 0.05). A significant correlation was found between rheumatoid factor (RF) and the subfoveal temporal choroidal thickness. CONCLUSION: Choroidal thickness in RA patients was higher than that in healthy participants. Choroidal thickening showed a positive correlation with RF, which may be an indicator for systemic vasculitis.

Effect of Corneal Incision Enlargement on Surgically Induced Astigmatism in Biaxial Microincision Cataract Surgery.

OBJECTIVES: To evaluate surgically induced astigmatism (SIA) in biaxial microincision cataract surgery with enlargement of one corneal incision during intraocular lens implantation (IOL). MATERIALS AND METHODS: Data from 683 eyes with cataract that underwent biaxial microincision cataract surgery and IOL were retrospectively analyzed. The operated eyes were divided into 4 groups defined by final corneal incision length after IOL implantation. There were 83 eyes with 1.6 mm corneal incisions (group 1) and 200 eyes in each of the 2, 2.4, and 2.8 mm corneal incision groups (groups 2, 3 and 4, respectively). SIA was assessed using preoperative and postoperative keratometric values at one month. RESULTS: The mean magnitude of SIA was 0.83±0.4 D in group 1, 0.93±0.5 D in group 2, 1.03±0.6 D in group 3 and 1.04±0.7 D in group 4. The SIA showed statistically significant differences between the four groups (p=0.05). Pairwise group comparisons revealed significant differences between groups 1 and 3 and groups 1 and 4 (p=0.005). CONCLUSION: Biaxial microincision cataract surgery with an incision size of 1.6 mm resulted in the least SIA. Enlargement of the corneal incision beyond 2.0 mm during IOL implantation led to significant increases in SIA. We believe that with the development and dissemination of IOLs which can be inserted through small corneal incisions, biaxial microincision cataract surgery will be the best choice to prevent SIA and increase visual acuity.

Serum prolidase activity and oxidative stress in patients with pseudoexfoliation syndrome.

PURPOSE: We aimed to evaluate the serum prolidase activity (SPA), malondialdehyde (MDA), and catalase levels in patients with pseudoexfoliation (PEX) syndrome. METHOD: Thirty-four patients with PEX syndrome and thirty-eight age- and gender-matched healthy subjects were included in this prospective clinical study. Each participant underwent full ophthalmologic examination. The SPA, serum MDA, and catalase levels were measured and compared between the patients with PEX syndrome and healthy subjects. RESULTS: The SPA was significantly lower in patients with PEX syndrome compared to healthy controls (14.1 ± 7.1 vs. 30.1 ± 4.3 ng/ml; p = 0.001). The mean serum MDA values the of PEX syndrome and control groups were comparable (28.7 ± 5.7 vs. 30.4 ± 5.3 nmol/ml, respectively; p = 0.185). The mean serum catalase level tended to be lower in the PEX group compared to healthy controls (0.12 ± 0.02 vs. 0.21 ± 0.05 k/ml, respectively; p = 0.077). CONCLUSION: Our findings suggest that the SPA was significantly lower in patients with PEX syndrome compared to healthy controls. Thus, prolidase may have a role in the pathogenesis of the PEX syndrome.

Comparison of the biometric formulas used for applanation A-scan ultrasound biometry.

The purpose of the study was to compare the accuracy of various biometric formulas for predicting postoperative refraction determined using applanation A-scan ultrasound. This retrospective comparative study included 485 eyes that underwent uneventful phacoemulsification with intraocular lens (IOL) implantation. Applanation A-scan ultrasound biometry and postoperative manifest refraction were obtained in all eyes. Biometric data were entered into each of the five IOL power calculation formulas: SRK-II, SRK/T, Holladay I, Hoffer Q, and Binkhorst II. All eyes were divided into three groups according to axial length: short (≤22.0 mm), average (22.0-25.0 mm), and long (≥25.0 mm) eyes. The postoperative spherical equivalent was calculated and compared with the predicted refractive error using each biometric formula. The results showed that all formulas had significantly lower mean absolute error (MAE) in comparison with Binkhorst II formula (P < 0.01). The lowest MAE was obtained with the SRK-II for average (0.49 ± 0.40 D) and short (0.67 ± 0.54 D) eyes and the SRK/T for long (0.61 ± 0.50 D) eyes. The highest postoperative hyperopic shift was seen with the SRK-II for average (46.8 %), short (28.1 %), and long (48.4 %) eyes. The highest postoperative myopic shift was seen with the Holladay I for average (66.4 %) and long (71.0 %) eyes and the SRK/T for short eyes (80.6 %). In conclusion, the SRK-II formula produced the lowest MAE in average and short eyes and the SRK/T formula produced the lowest MAE in long eyes. The SRK-II has the highest postoperative hyperopic shift in all eyes. The highest postoperative myopic shift is with the Holladay I for average and long eyes and SRK/T for short eyes.

Refractive Results Using a New Optical Biometry Device: Comparison With Ultrasound Biometry Data.

The aim of the study was to compare the measurements of optical (AL-Scan; Nidek Co., Ltd.) and ultrasonic (Echo Scan US-800; Nidek Co., Ltd.) biometry devices and to assess refractive results after cataract surgery. Eighty-one cataractous eyes of 81 patients were included in this study. Biometry was performed using the AL-Scan and an ultrasonic biometer (USB). Axial length (AL), keratometry (K) data, and intraocular lens (IOL) power calculations using the SRK/T formula were compared. Bland-Altman analysis was used to assess the extent of agreement between AL-Scan and USB data in terms of AL measurement and IOL power calculation. The K measurements of the AL-Scan were compared to autorefractor data (Canon Autorefractor RK-F1). The AL-Scan assessed the AL as longer (average difference 0.06 ± 0.18 mm; ICC = 0.987; P < 0.001) and the IOL power as greater (average difference 0.19 ± 0.66 D; ICC = 0.964; P < 0.001) than the USB. The AL-Scan also measured average K values (average difference 0.25 ± 0.25 D; ICC = 0.985; P < 0.001) greater than those given by the autorefractor. The postoperative mean absolute error was +0.30 ± 0.04 D (minimum: -0.51 D, maximum +1.04 D). The postoperative mean K value change was 0.36 ± 0.29 D (P < 0.05). The differences between measurements afforded by the AL-Scan and USB may be clinically acceptable. Keratometric changes that develop after cataract operations compromise the attainment of good refractive outcomes.

Management of hypotony and flat anterior chamber associated with glaucoma filtration surgery.

AIM: To determine the effectiveness of pharmacological and interventional treatment of hypotony and flat anterior chamber (FAC) resulting from glaucoma filtration surgery. METHODS: We retrospectively examined the medical records of fifty-two trabeculectomy patients (52 eyes) who developed postoperative hypotony and FAC. The management and associated complications of hypotony, changing intraocular pressure (IOP) and best corrected visual acuity (BCVA) were evaluated. RESULT: Of the 52 patients with hypotony, 29 (56%) had a grade 1 FAC, 21 (40%) had a grade 2 FAC, and only 2 had a grade 3 FAC. There was no significant difference between the mean preoperative IOP and the mean IOP at three and six months after surgery. Thirteen eyes (25%) required antiglaucomatous medication three months after surgery. The mean BCVA at 6mo after surgery was significantly reduced as compared with the mean preoperative BCVA. CONCLUSION: Hypotonia and FAC following trabeculectomy are associated with troublesome complications that require pharmacological and/or surgical treatment. Thus, close follow-up is essential for affected patients.

Analysis of the Retinal Nerve Fiber Layer in Retinitis Pigmentosa Using Optic Coherence Tomography.

Aim. To evaluate the peripapillary retinal nerve fiber layer (RNFL) changes in retinitis pigmentosa (RP) patients using spectral domain optic coherence tomography (Sd-OCT). Methods. We retrospectively examined medical records of forty-four eyes of twenty-two RP patients. The results were also compared with those of previously reported forty-four eyes of twenty-two normal subjects (controls). Records of average and four quadrants peripapillary RNFL thickness measurements using Sd-OCT were assessed. Results. In RP patients the mean RNFL thickness was 97.57 ± 3.21 µm. The RNFL in the superior, temporal, nasal, and inferior quadrants was 119.18 ± 4.47 µm, 84.68 ± 2.31 µm, 75.09 ± 3.34 µm, and 113.88 ± 4.25 µm, respectively. While the thinning of RNFL was predominantly observed in the inferior quadrant, the thickening was mostly noted in temporal quadrant. The differences between mean, superior, and nasal quadrant RNFL thicknesses were not statistically significant when compared with control group. The RP patients had thinner inferior quadrant and thicker temporal quadrant than control group (p < 0.05). Conclusion. Sd-OCT is highly sensitive and effective instrument to detect RNFL changes in RP patients. RNFL measurements can provide information about the progression of retinitis pigmentosa and may provide prognostic indices for future treatment modalities.

Assessment of anterior suspended flaps modification for external dacryocystorhinostomy.

AIM: The aim of this study was to evaluate the functional and/or anatomic success rate as well as complications of anterior suspended flaps modification for external dacryocystorhinostomy (DCR). METHODS: This is a retrospective study that included 50 eyes of 47 patients who underwent anterior suspended flap external DCR surgery for nasolacrimal duct obstruction. Diagnosis of nasolacrimal duct obstruction was made through irrigation of the nasolacrimal drainage system. Anterior flaps of lacrimal sac and nasal mucosa, as large as possible, were created in all patients. Posterior flaps of lacrimal sac and exposed nasal mucosa were excised. After suturing the anterior flaps with two 6-0 Vicryl sutures, the third suture was passed through the orbicularis oculi at the subcutaneous level on 1 edge of incision, then from the middle of the anterior flaps and the other edge of the incision to the suspended anterior flaps. RESULTS: The success rate of 50 surgeries was 96%. In 37 eyes, no problems were reported during the surgery and the modified external DCR was performed successfully. The success rate of the modified external DCR was 100% in those patients. The average operation time was 34 ± 8.2 minutes. CONCLUSIONS: These results suggest that anterior suspended flap external DCR is a simple, safe technique with a very high success rate and a satisfactory surgical time.

Tear function in patients with chronic renal failure undergoing hemodialysis.

OBJECTIVES: To evaluate dry eye symptoms and clinical tear film alterations in patients with chronic renal failure (CRF). MATERIALS AND METHODS: Thirty-five non-diabetic CRF patients undergoing hemodialysis, and 31 healthy individuals were enrolled. An ocular surface disease index questionnaire (OSDI) was administered, and after a complete ocular examination, Schirmer and tear break-up time (TBUT) tests were performed. RESULTS: OSDI scores were significantly higher (p<0.01) and TBUT tests were significantly lower (p=0.01) in CRF patients than in the control group. Schirmer test results were also lower in the CRF patients group, but lacked statistical significance (p=0.20). CONCLUSION: Patients with CRF should be advised to obtain an ophthalmic examination, especially for dry eye.

Prevalence of keratoconus and subclinical keratoconus in subjects with astigmatism using pentacam derived parameters.

PURPOSE: To determine the prevalence of keratoconus (KCN) and subclinical KCN among subjects with two or more diopters (D) of astigmatism, and to compare Pentacam parameters among these subjects. METHODS: One hundred and twenty eight eyes of 64 subjects with astigmatism ≥2D were included in the study. All subjects underwent a complete ophthalmic examination which included refraction, visual acuity measurement, slit lamp biomicroscopy, retinoscopy, fundus examination, conventional corneal topography and elevation-based topography with Pentacam. The diagnosis of KCN and subclinical KCN was made by observing clinical findings and topographic features; and confirmed by corneal thickness and elevation maps of Pentacam. Several parameters acquired from Pentacam were analyzed employing the Mann-Whitney U Test. RESULTS: Mean age of the study population was 29.9±9.8 (range 15-45) years which included 39 (60.9%) female and 25 (39.1%) male subjects. Maximum corneal power, index of vertical asymmetry, keratoconus index and elevation values were significantly higher and pachymetry was significantly thinner in eyes with clinical or subclinical KCN than normal astigmatic eyes (P< 0.05). CONCLUSION: The current study showed that subjects with 2D or more of astigmatism who present to outpatient clinics should undergo corneal topography screening for early diagnosis of KCN even if visual acuity is not affected. Pentacam may provide more accurate information about anterior and posterior corneal anatomy especially in suspect eyes.