Mincheol Seong

Macular and Peripapillary Retinal Nerve Fiber Layer Measurements by Spectral Domain Optical Coherence Tomography in Normal-Tension Glaucoma

PURPOSE To evaluate and compare the glaucoma discrimination ability of macular inner retinal layer (MIRL) thickness with that of peripapillary retinal nerve fiber layer (pRNFL) thickness measured by spectral-domain optical coherence tomography (RTVue-100; Optovue Inc, Fremont, CA) in patients with normal-tension glaucoma (NTG). METHODS Sixty-five healthy subjects and 102 with NTG were enrolled. MIRL thickness provided by a ganglion cell complex (GCC) scan and two RNFL thicknesses measured by the NHM4 (RNFL1) and RNFL 3.45 (RNFL2) modes of the RTVue-100 system were analyzed. The areas under the receiver operating characteristic curves (AUCs) of MIRL and pRNFL thicknesses for discriminating patients with NTG from control subjects were determined. The AUCs were compared between patients with central visual field (VF) defects (VF; <or=10 degrees of fixation) and peripheral VF defects (>10 degrees from fixation). RESULTS The average MIRL thickness showed a strong correlation with both RNFL1 and -2 thicknesses (R(2) = 0.773, 0.774, both P < 0.0001). The AUCs for average MIRL, RNFL1, and RNFL2 thicknesses were not significantly different at 0.945, 0.973, and 0.976, respectively. However, the AUCs of the average and superior MIRL thicknesses were significantly less than that of the pRNFL thickness in eyes with moderate-to-advanced glaucoma and eyes with peripheral VF defects. CONCLUSIONS The average MIRL thickness showed a strong correlation with pRNFL thickness, because patients with NTG at an early stage showed paracentral VF defects near the fixation point. MIRL thickness showed glaucoma discrimination ability comparable to that of pRNFL thickness in patients with NTG with early VF defects. In eyes with advanced or peripheral VF defect, pRNFL measurement showed a better glaucoma diagnostic ability than did MIRL measurement.

Ability of Stratus OCT to detect progressive retinal nerve fiber layer atrophy in glaucoma.

PURPOSE To evaluate the ability of Stratus optical coherence tomography (OCT version 4.0; Carl Zeiss Meditec, Inc., Dublin, CA) to detect progressive glaucomatous retinal nerve fiber layer (RNFL) atrophy observed by red-free RNFL photography. METHODS Intersession test-retest variability of each clock hour, quadrant, and average RNFL thickness was determined in 53 control subjects. The sensitivity and specificity of OCT for identification of progressive RNFL atrophy were tested on subjects in whom this condition was clearly observed in red-free RNFL photographs (n=27) and in another control group (n=62), according to criteria derived from test-retest variability. RESULTS The sensitivity of Stratus OCT RNFL measurement ranged from 14.8% (for average RNFL thickness) to 85.2% (for clock hour thickness) when tested at the 95% confidence level. The specificity of Stratus OCT RNFL measurement was approximately 95% for average RNFL thickness, but decreased considerably with clock hour (59.7%) and quadrant thickness (77.4%). This is presumably because multiple testing was used for multiple clock hours and quadrants. When calculated based on two consecutive follow-up examinations, the specificity for the clock hour measurements increased to 86.6% and that for quadrant thickness increased to 92.5%. The OCT-measured RNFL thickness change showed excellent topographic agreement with the progressive RNFL atrophy observed using RNFL photography. CONCLUSIONS Within the limits of retest variability, Stratus OCT detects progressive RNFL atrophy with high sensitivity and moderate specificity in cases showing localized progressive loss of retinal nerve fibers in red-free photographs. The specificity can be improved by use of multiple measurements. Stratus OCT is a potentially useful technique for detection of glaucoma progression.

Comparison of aqueous concentrations of angiogenic and inflammatory cytokines in diabetic macular oedema and macular oedema due to branch retinal vein occlusion

Aims The involvement of cytokines in the aqueous humour is important in the development and progression of diabetic macular oedema (DMO) and macular oedema (MO) due to branch retinal vein occlusion (BRVO-MO). In this study, the concentrations of cytokines in the aqueous humour of eyes with DMO and BRVO-MO were measured and compared. Methods Prospective, observational case series. Aqueous samples were obtained from 18 eyes with DMO (DMO group), 12 eyes with BRVO-MO (BRVO-MO group), and 16 normal eyes (control group). The aqueous levels of cytokines, including interleukin (IL)-2, IL-5, IL-6, IL-8, IL-12p70, IL-13, monocytochemotactic protein-1 (MCP-1), macrophage inflammatory protein-1α (MIP-1α), platelet-derived growth factor-AA (PDGF)-AA, transforming growth factor-α (TGF-α), interferon-γ (IFN-γ), epidermal growth factor, fibroblast growth factor 2 (FGF2) and vascular endothelial growth factor (VEGF), were measured. Results The aqueous levels of IL-8, MCP-1, PDGF-AA and VEGF were higher, and IL-13 was lower in the DMO group compared with the control group. The aqueous levels of IL-8 and VEGF were higher in the BRVO-MO group than in the control group. Compared with the IL-6 and MCP-1 levels in the BRVO-MO group, those levels were significantly higher in the DMO group. Correlation analyses revealed that IL-8 was positively and IFN-γ was negatively correlated with the severity of MO in the DMO group. In the BRVO-MO group, IL-8 and was positively correlated with severity of MO and retinal ischaemia. Conclusions DMO and BRVO-MO may differ in terms of pathogenesis because the cytokine concentrations in the aqueous humour differ. The results suggest that the inflammatory reaction may be more activated in DMO than in BRVO-MO, and ischaemic insult may play a central role in the development of BRVO-MO.

Risk factors associated with optic disc haemorrhage in patients with normal tension glaucoma.

PurposeTo evaluate the risk factors associated with optic disc haemorrhage in patients with normal tension glaucoma (NTG).Patients and methodsTwo hundred and eighty-one eyes of 281 patients with NTG (113 eyes with optic disc haemorrhage and 168 eyes without haemorrhage) were included in this study. Associations between optic disc haemorrhage and various patient-related variables (diabetes; hypertension; hypotension; cardiac disease; stroke; cold hand; migraine; constipation; use of steroids, aspirin, anticoagulant, or gingko extract; smoking history; and glaucoma family history) and eye-related variables (baseline intraocular pressure (IOP); maximum, minimum, and range of IOP; vertical and horizontal cup/disc ratio; mean deviation and pattern standard deviation of the visual field; corneal thickness; and average retinal nerve fibre layer (RNFL) thickness measured by optical coherence tomography) were investigated by univariate and multivariate logistic regression analyses. Differences in risk factors between patients with single optic disc haemorrhages and recurrent haemorrhages were also analysed.ResultsOptic disc haemorrhage was associated with systemic hypertension (odds ratio, 1.998; 95% confidence interval, 1.094–3.651; P=0.001). IOP range (P=0.080), diabetes (P=0.056), and use of aspirin (P=0.079) also tended to be associated with optic disc haemorrhage. No risk factor was significantly different between the single haemorrhage group and the recurrent haemorrhage group.ConclusionOptic disc haemorrhage was associated with systemic hypertension in patients with NTG.

The Relationship Between Diabetic Retinopathy and Diabetic Nephropathy in a Population-Based Study in Korea (KNHANES V-2, 3)

PURPOSE To determine the risk factors for and relationship between diabetic retinopathy (DR) and diabetic nephropathy (DN), including microalbuminuria and overt nephropathy, in a population-based study of diabetes mellitus (DM) patients in Korea. METHODS This was a population-based, cross-sectional study. From the fifth (2011, 2012) Korea National Health and Nutrition Examination Survey (KNHANES), 971 participants with type 2 DM were included. The prevalence of DR and DN was determined. Multivariate logistic regression was performed to determine risk factors, including DR, associated with DN in the Korean population. RESULTS In DM patients, we observed a prevalence of 20.0% for any DR and 3.8% for proliferative diabetic retinopathy (PDR). Microalbuminuria prevalence was 19.3% and overt nephropathy prevalence was 5.5%. The risk factors of microalbuminuria were presence of hypertension; higher systolic blood pressure, serum hemoglobin A1c (HbA1c), and serum blood urea nitrogen level; as well as the presence of PDR. The risk factors of overt nephropathy were long duration of DM; high levels of HbA1c, systolic blood pressure, total cholesterol, and serum creatinine; as well as the presence of DR CONCLUSIONS: Proliferative diabetic retinopathy is associated with microalbuminuria and DR is associated with overt nephropathy in Korean DM patients. Our findings suggest that when an ophthalmologist finds the presence of DR or PDR, timely evaluation of the patients renal status should be recommended.

Ischemic diabetic retinopathy as a possible prognostic factor for chronic kidney disease progression.

PurposeTo assess the value of diabetic retinopathy (DR) severity as a possible predictive prognostic factor for the progression of chronic kidney disease (CKD).Patients and methodsRetrospective cohort study. Patients (51) who were initially diagnosed with DR and CKD were enrolled and their medical records were evaluated. The following ophthalmic factors were assessed by fluorescein angiography at the initial visit: area of capillary nonperfusion, presence of neovascularization and vitreous hemorrhage, and DR grade. The effect of these factors on CKD progression over the 2-year period of the study, defined as doubling of serum creatinine or the development of end-stage renal disease requiring dialysis or renal transplant, was evaluated.ResultsThe study included 51 patients with DR and CKD; of these, 11 patients (21.6%) were found to have proliferative DR (PDR) and seven patients (13.7%) had high-risk PDR at baseline. Patients with ischemic DR, who showed extensive capillary nonperfusion (≥10 optic disc areas) in the retina, had a greater risk for CKD progression (hazard ratio=6.64; P=0.002).ConclusionWe found that extensive capillary nonperfusion in the retina greatly increased the risk of progression of CKD in patients with DR. This suggests that the retina and the kidney may have shared risk factors for microvascular disease secondary to diabetes mellitus, and emphasizes the need for a team approach to diabetes care.

Clinical Measurement of the Angle of Ocular Movements in the Nine Cardinal Positions of Gaze

PURPOSE To measure the maximum angle of ocular versions using photographs of the 9 cardinal positions and a modified limbus test. DESIGN An evaluation of diagnostic technology; a prospective observational study. PARTICIPANTS We enrolled 104 healthy subjects, 20 to 40 years of age. METHODS Photographs were obtained in the 9 cardinal positions of gaze and the images were processed using Photoshop. The images were analyzed using the Image J program to measure the angle of version. The maximum angle of the 9 cardinal positions was quantified using a modified limbus test. MAIN OUTCOME MEASURES We measured the maximum angle of ocular versions in the 9 cardinal positions of gaze. We also compared the results for males and females. RESULTS The mean angles of maximum version were adduction 47.4°, abduction 46.4°, elevation 31.8°, depression 47.8°, elevation in adduction 39.7°, elevation in abduction 40.7°, depression in adduction 52.7°, and depression in abduction 49.2°. The mean angle of maximum elevation was significantly smaller than that of depression (P <0.001). There were no correlations between the angle of maximum version and age, spherical equivalents, or axial length. The angle of maximum version for males was significantly greater than that for females, except for inferior gaze. CONCLUSIONS A modified limbus test using photographs of the 9 cardinal positions is an objective and reproducible tool for quantifying ocular movement. Considering its simplicity, ease of use, and low cost, it has clear applications in clinical practice.

Retinal nerve fiber layer volume measurements in healthy subjects using spectral domain optical coherence tomography.

Purpose:To report retinal nerve fiber layer (RNFL) volume measurement using spectral domain optical coherence tomography (SD-OCT). We determined the characteristics and effecting factors of the RNFL volume in healthy eyes. Methods:Eighty-six eyes from 86 healthy volunteers were included. All participants underwent 3D-disc scanning using SD-OCT. We developed a computer program using Matlab software to extract RNFL thickness values from colored topographic RNFL thickness map. Total average, quadrant, and clock-hour RNFL volume were automatically calculated between 2.5 and 5 mm diameter circles using the length, width, and height of each pixel derived from the RNFL thickness map. Results:The mean total RNFL volume was 1.478±0.124 mm3 and RNFL volume profiles showed double-hump patterns. RNFL volumes of superior and inferior quadrants were significantly greater than those of temporal and nasal quadrants (all P<0.001). A strong correlation existed between RNFL volume and conventional circumpapillary RNFL thickness measured by built-in software (R=0.895 to 0.972). Image quality and age were associated with RNFL volume measurement. Conclusions:RNFL volume measurement from RNFL thickness map analysis provides an alternative approach to characterizing and evaluating RNFL. RNFL volume measurement may be valuable for the objective and quantitative evaluation of 3-dimensional RFNL changes.

Quantitative Assessment of Inferior Oblique Muscle Overaction Using Photographs of the Cardinal Positions of Gaze

PURPOSE To report a novel method for measuring the degree of inferior oblique muscle overaction and to investigate the correlation with other factors. DESIGN Cross-sectional diagnostic study. METHODS One hundred and forty-two eyes (120 patients) were enrolled in this study. Subjects underwent a full orthoptic examination and photographs were obtained in the cardinal positions of gaze. The images were processed using Photoshop and analyzed using the ImageJ program to measure the degree of inferior oblique muscle overaction. Reproducibility or interobserver variability was assessed by Bland-Altman plots and by calculation of the intraclass correlation coefficient (ICC). The correlation between the degree of inferior oblique muscle overaction and the associated factors was estimated with linear regression analysis. RESULTS The mean angle of inferior oblique muscle overaction was 17.8 ± 10.1 degrees (range, 1.8-54.1 degrees). The 95% limit of agreement of interobserver variability for the degree of inferior oblique muscle overaction was ±1.76 degrees, and ICC was 0.98. The angle of inferior oblique muscle overaction showed significant correlation with the clinical grading scale (R = 0.549, P < .001) and with hypertropia in the adducted position (R = 0.300, P = .001). The mean angles of inferior oblique muscle overaction classified into grades 1, 2, 3, and 4 according to the clinical grading scale were 10.5 ± 9.1 degrees, 16.8 ± 7.8 degrees, 24.3 ± 8.8 degrees, and 40.0 ± 12.2 degrees, respectively (P < .001). CONCLUSIONS We describe a new method for measuring the degree of inferior oblique muscle overaction using photographs of the cardinal positions. It has the potential to be a diagnostic tool that measures inferior oblique muscle overaction with minimal observer dependency.

The effect of pattern scan laser photocoagulation on peripapillary retinal nerve fiber layer thickness and optic nerve morphology in diabetic retinopathy.

Purpose To evaluate the effect of pattern scan laser (PASCAL) photocoagulation on peripapillary retinal nerve fiber layer (RNFL) thickness, central macular thickness (CMT), and optic nerve morphology in patients with diabetic retinopathy. Methods Subjects included 35 eyes for the PASCAL group and 49 eyes for a control group. Peripapillary RNFL thickness, cup-disc area ratio and CMT were measured before PASCAL photocoagulation and at 2 and 6 months after PASCAL photocoagulation in the PASCAL or control groups. Results The average RNFL thickness had increased by 0.84 µm two months after and decreased by 0.4 µm six months after PASCAL photocoagulation compared to baseline, but these changes were not significant (p = 0.83, 0.39). The cup-disc area ratio was unchanged after PASCAL photocoagulation. CMT increased by 18.11 µm (p = 0.048) at two months compared to baseline thickness, and partially recovered to 11.82 µm (p = 0.11) at six months in the PASCAL group. Conclusions PASCAL photocoagulation may not cause significant change in the peripapillary RNFL thickness, CMT, and optic nerve morphology in patients with diabetic retinopathy.