Pulsatile ocular blood flow in patients with Graves' ophthalmopathy

Orbital and ocular perfusion in thyroid eye disease

Thyroid eye disease (TED) is characterized by enlargement of extraocular muscles, an increase in retrobulbar fat, orbital fibrosis, and fluctuations in plasma thyroid hormone levels in most patients, often associated with raised autoantibody titers. The occurrence of orbital space conflict compromises the orbital perfusion, unchecked progression of which results in irreversible loss of visual acuity and visual fields. The quantitative assessment of orbital perfusion can be done by measurement of blood flow velocities in the superior ophthalmic vein (SOV), ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary artery by color Doppler imaging. The retinal and choroidal microvasculature is studied by optical coherence tomography and optical coherence tomography angiography. The orbital and ocular perfusion fluctuates during the course of TED. Orbital congestion is reflected by the reduction or reversal of SOV flow and an increase in subfoveal choroidal thickness. The active phase is characterized by high blood flow velocities of the OA and CRA. The onset of dysthyroid optic neuropathy is associated with reduced arterial perfusion and reduction in parafoveal and peripapillary vascular density. Orbital decompression improves the SOV flow and decreases the resistivity index of CRA. Sequential evaluation of orbital hemodynamic changes can thus supplement the clinical scoring systems for monitoring and planning intervention in TED.

Applications of a novel reciprocating positive displacement pump in the simulation of pulsatile arterial blood flow

Pulsatile arterial blood flow plays an important role in vascular system mechanobiology, especially in the study of mechanisms of pathology. Limitations in cost, time, sample size, and control across current in-vitro and in-vivo methods limit future exploration of novel treatments. Presented is the verification of a novel reciprocating positive displacement pump aimed at resolving these issues through the simulation of human ocular, human fingertip and skin surface, human cerebral, and rodent spleen organ systems. A range of pulsatile amplitudes, frequencies, and flow rates were simulated using pumps made of 3D printed parts incorporating a tubing system, check valve and proprietary software. Volumetric analysis of 430 total readings across a flow range of 0.025ml/min to 16ml/min determined that the pump had a mean absolute error and mean relative error of 0.041 ml/min and 1.385%, respectively. Linear regression analysis compared to expected flow rate across the full flow range yielded an R2 of 0.9996. Waveform analysis indicated that the pump could recreate accurate beat frequency for flow ranges above 0.06ml/min at 70BPM. The verification of accurate pump output opens avenues for the development of novel long-term in-vitro benchtop models capable of looking at fluid flow scenarios previously unfeasible, including low volume-high shear rate pulsatile flow.

Choroidal structural evaluation in inactive Graves' ophthalmopathy

PURPOSE

To investigate the changes in the choroidal structure in patients with inactive Graves Ophthalmopathy (GO).

DESIGN

A prospective, masked, observational cross-sectional study.

METHODS

Changes in choroidal vascularity index (CVI) were studied in the patients with inactive GO using binarization on enhanced depth imaging optical coherence tomography (EDI-OCT) images. Choroidal area, subfoveal choroidal thickness (SFCT), stromal area, luminal area, CVI and retinal nerve fiber layer (RNFL) thickness was used to compare the eyes of sixty-four age-, gender-matched healthy subjects. All measurements were done separately both subfoveal (1500 µm) and total choroidal area (7500 µm). The relation between CVI or SFCT and age, gender, duration of disease, the severity of disease, TRAb (thyrotropin receptor autoantibody), smoking status, and exophthalmometer readings were evaluated.

RESULTS

There were 56 patients (30 female, 26 male; mean age: 39.5 ± 11.4 years) in the GO group and 64 patients (34 female, 30 male; mean age: 42.2 ± 5.6 years) in the healthy subject group. There was no statistically significant difference between subjects with GO and healthy controls regarding age (p = 0.24) and gender distribution (p = 0.55). Patients with GO had significantly higher intraocular pressure (p = 0.001) and exophthalmometer readings (p = 0.0001) than the healthy controls. The SFCT, CVI₁₅₀₀ and the stromal area1500 was significantly different between the groups (p = 0.009, p = 0.009, p = 0.011, respectively). Multivariate analysis showed that age (-0.871, p = 0.02) was highly correlated with the decreased SFCT, and duration of disease (0.524, p = 0.001) was significantly positively correlated with SFCT. Luminal area1500 (-0.416, p = 0.0001)and stromal area1500 (-0.657, p = 0.0001) were significantly negatively correlated with CVI₁₅₀₀ in the patients with GO.

CONCLUSION

Although higher CVI₁₅₀₀ was observed in GO patients than in healthy controls, the degree of increase was not the same in the CVI₇₅₀₀. Age and duration of disease significantly affect the SFCT, and luminal area₁₅₀₀ and stromal area₁₅₀₀ significantly affect the CVI₁₅₀₀.

Choroidal vascularity index in thyroid-associated ophthalmopathy: a cross-sectional study

Background

Hemodynamic changes have been observed in patients with Graves’ disease. The aim of our study was to evaluate choroidal vascular change using the choroidal vascularity index (CVI) in patients with thyroid-associated ophthalmopathy (TAO).

Methods

In this cross-sectional observational study, 40 patients affected by TAO were recruited. Forty healthy individuals, matched for age and sex, served as controls. Foveal enhanced-depth imaging optical coherence tomography scans were obtained from all participants. Images were binarized using the ImageJ software and luminal area (LA) and total choroidal area (TCA) were measured. CVI was calculated as the proportion of LA to TCA. The relation between CVI or subfoveal choroidal thickness (SFCT) and clinical activity score, exophthalmometric value, diplopia status, gender, and age was evaluated.

Results

CVI was significantly higher in patients with TAO (P = 0.004). No significant difference was observed in SFCT (P = 0.200) and TCA (P = 0.153) comparing TAO patients and healthy controls. LA was significantly higher in TAO group (P = 0.045). On multiple regression analysis, CVI was associated with TCA (P = 0.043). No association was found between SFCT or CVI and TCA, clinical activity score, exophthalmometric value, Inami value, diplopia status, gender or age (P > 0.05).

Conclusions

This is the first study that has demonstrated an increase in CVI in eyes with TAO compared with healthy controls and has assessed its association with clinical features.

Risk Factors of Thyroid Eye Disease

OBJECTIVE

To examine risk factors that might be associated with thyroid eye disease (TED) in patients with Graves' disease (GD), which may guide physicians in the prevention and management of TED.

METHODS

Medline and Embase were searched for articles discussing risk factors of TED. Comparisons were made between GD patients with and without TED, and between active and inactive TED GD patients. Weighted mean differences (WMDs) and odds ratios (ORs) were determined for continuous and dichotomous outcomes, respectively. Results were pooled with random effects using the DerSimonian and Laird model.

RESULTS

Fifty-six articles were included in the analysis. Smoking, inclusive of current and previous smoking status, was a significant risk factor for TED (OR: 2.401; CI: 1.958-2.945; P < .001). Statistical significance was found upon meta-regression between male sex and the odds of smoking and TED (β = 1.195; SE = 0.436; P = .013). Other risk factors were also examined, and patients with TED were significantly older than those without TED (WMD: 1.350; CI: 0.328-2.372; P = .010). While both age (WMD: 5.546; CI: 3.075-8.017; P < .001) and male sex (OR: 1.819; CI: 1.178-2.808; P = .007) were found to be significant risk factors for active TED patients compared to inactive TED patients, no statistical significance was found for family history, thyroid status, cholesterol levels, or body mass index.

CONCLUSION

Factors such as smoking, sex, and age predispose GD patients to TED, and TED patients to active TED. A targeted approach in the management of GD and TED is required to reduce the modifiable risk factor of smoking.

Retinal vascularity, nerve fiber, and ganglion cell layer thickness in thyroid eye disease on optical coherence tomography angiography

Purpose: To compare the retinal vascularity, peripapillary vascularity, nerve fiber layer thickness and ganglion cell layer thickness between active, inactive thyroid eye disease (TED) and healthy eyes.Methods: Retrospective comparative cross-sectional cohort study. Patients with TED, active and inactive on the VISA score, and healthy eyes were included. All patients underwent optical coherence tomography angiography with detailed demographic and clinical data capture. Using automated software, retinal and peripapillary vascularity index, nerve fiber layer thickness, and ganglion cell layer thickness were calculated and were compared between the groups.Results: Twenty-four eyes with active TED, 102 eyes with inactive TED and 52 healthy eyes were included. Independent sample t test was used to compare parametric data and Mann-Whitney test to compare non-parametric data. The age and gender were comparable across groups. The peripapillary vascularity index (26.82 ± 4.13 versus 34.92 ± 5.08, p = .002) and the macular vascularity index (20.32 ± 2.5 versus 31.21 ± 3.89, p < .0001) were reduced in active TED eyes versus inactive eyes. Macular vascularity index was comparable in the inactive versus the healthy eyes. The RNFL thickness was increased in the active TED eyes versus the inactive eyes (45.11 ± 18.3 versus 35.55 ± 7, p = .03) and active versus healthy eyes (45.11 ± 18.3 versus 36.28 ± 7.89, p = .03). Ganglion cell layer thickness between all three groups was comparable.Conclusion: Decrease in peripapillary and macular vascular density and increase in RNFL thickness are seen in active TED compared to inactive TED and healthy eyes. In disease inactivity, these parameters are comparable to healthy eyes.

Prevalence of thyroid eye disease in Graves' disease: A meta-analysis and systematic review

OBJECTIVE

Thyroid eye disease (TED) is a debilitating condition that frequently manifests in patients suffering from Graves' disease (GD). This study aims to analyse the prevalence of TED among GD patients, with a focus on geographical region-specific rates.

METHODS

Medline and Embase were searched for articles examining TED prevalence on April 2020, and articles were retrieved and sieved. Statistical analysis was performed after Freeman-Tukey double arcsine transformation. Thereafter, results were pooled with random effects by DerSimonian and Laird model.

RESULTS

Fifty-seven articles involving 26,804 patients were included in the review. The overall pooled prevalence of TED was 40% (CI: 0.32 to 0.48) and by continent was 38% (CI: 0.31 to 0.46) for Europe, 44% (CI: 0.32 to 0.56) for Asia, 27% (CI: 0.06 to 0.56) for North America and 58% (CI: 0.55 to 0.61) for Oceania. The prevalence of TED in Southeast Asia was 35% (CI: 0.24 to 0.47) and Middle East 48% (CI: 0.19 to 0.78). Subgroup analysis showed regions with predominantly Caucasians (37%; CI: 0.28 to 0.46) had a lower prevalence of TED compared to Asians (45%; CI: 0.33 to 0.58). The pooled prevalence of lid retraction was 57% (CI: 0.39 to 0.74), proptosis 57% (CI: 0.48 to 0.65), diplopia 36% (CI: 0.24 to 0.48) and ocular hypertension 13% (CI: 0.06 to 0.19).

CONCLUSION

A substantial proportion of patients with GD have TED and often manifest as lid retraction, proptosis and diplopia. Early detection through active screening might help to mitigate the progression of TED and its associated complications.

Evaluation of choroidal thickness and retinal vessel density in patients with inactive Graves' orbitopathy

BACKGROUND

To investigate choroidal thickness using spectral domain-optical coherence tomography and retinal vessel density with optical coherence tomography angiography in patients with inactive Graves' orbitopathy.

METHODS

A total of 36 eyes of 36 patients with inactive Graves' orbitopathy (6 men and 30 women in Group 1) and 36 eyes from 36 controls (8 men and 28 women in Group 2) were recruited for this prospective case-control study. Choroidal thickness measurements were obtained using enhanced depth imaging with spectral domain-optical coherence tomography. Optical coherence tomography angiography images were generated with 6 × 6-mm angiographic optical coherence tomography scans. Retinal vessel densities of the superficial retinal layer and deep retinal layer of the macula and foveal avascular zone measurements were obtained for each eye.

RESULTS

The mean age was 42.5 ± 9.9 years in Group 1 and 42.8 ± 6.5 years in Group 2 (p = 0.76). The mean choroidal thickness was 370.7 ± 83.5 μm and 338.2 ± 72.4 μm in Group 1 and 2, respectively (p = 0.09). There was no significant difference between the groups in retinal vessel density either in superficial or deep retinal layers (p > 0.05 for all), and no difference was found between the groups in foveal avascular zone area and perimeter (p = 0.69, p = 0.73, respectively).

CONCLUSIONS

Similar retinal vessel density values were found in both superficial and deep retinal layers in Graves' orbitopathy compared with healthy subjects. Although statistically insignificant, choroidal thickness was slightly higher in patients with Graves' orbitopathy than in healthy subjects. Foveal avascular zone area and perimeter measurements were unaffected by the disease.

Do ocular pulse amplitude and choroidal thickness change in patients with thyroid eye disease?

Purpose: The aim of this study was to evaluate whether orbital changes induced by thyroid eye disease affect the ocular pulse amplitude and choroidal perfusion. Materials and Methods: A total of 38 eyes of 38 patients with thyroid eye disease (Group 1) and 38 eyes of 38 control individuals (Group 2) with normal intraocular pressure were enrolled in this study. Thyroid eye disease activity was defined using clinical activity score. Intraocular pressure measurement with Goldmann applanation tonometer, axial length, central corneal thickness, Hertel exophthalmometry and systolic and diastolic blood pressure measurements were taken from each patient. Ocular pulse amplitude and intraocular pressure were measured using dynamic contour tonometry. Choroidal thickness was measured by enhanced depth imaging-optical coherence tomography at subfoveal, nasal and temporal 1000 μm area. Results: Intraocular pressures measured with Goldmann applanation tonometer and dynamic contour tonometry and mean ocular pulse amplitude were not statistically different between groups. However mean choroidal thicknesses were significantly lower when compared to control group. Ocular pulse amplitude and intraocular pressure measurement with dynamic contour tonometry did not change significantly with the increase in clinical activity score. There was not statistically significant correlation between ocular pulse amplitude and choroidal thicknesses in patients with thyroid eye disease. Conclusion: Ocular pulse amplitude and choroidal perfusion were not found to change with orbital involvement in thyroid eye disease and with disease activity, especially in patients with normal intraocular pressure. Although choroidal thickness was thinner than control group, choroidal perfusion did not change as a compensatory mechanism for maintaining ocular homeostasis.

Choroidal thickness in thyroid-associated orbitopathy

IMPORTANCE

To investigate the choroidal thickness (CT) in patients with thyroid-associated orbitopathy (TAO).

BACKGROUND

To compare CT of TAO patients and healthy subjects.

DESIGN

Prospective cross-sectional study in a public hospital.

PARTICIPANTS

One hundred and four eyes of 52 TAO patients and 52 eyes of 26 healthy subjects.

METHODS

CT was measured with enhanced-depth imaging optical coherence tomography (EDI-OCT) at the subfoveal, macular and peripapillary regions. Multivariate linear regression was used to evaluate the associations of subfoveal CT with systemic and ocular variables among TAO eyes.

MAIN OUTCOME MEASURES

CT of both groups.

RESULTS

CT of eyes with TAO was significantly increased at the subfoveal region, 1 and 2 mm from the fovea nasally, temporally and superiorly, and 1 mm inferior to the fovea (all P < .05). No significant difference was found in CT at 2 mm inferior to the fovea (P = .094) and all four quadrants of the peripapillary region (superior, P = .096; nasal, P = .732; inferior, P = .179; temporal, P = .052). Among TAO eyes, thinner subfoveal choroid was associated with worsening exophthalmos (P = .043), poorer visual acuity (P = .017), increasing age (P = .040) and axial length (P < .001). There was no association between CT and clinical activity score (P = .239).

CONCLUSIONS AND RELEVANCE

TAO patients showed thicker choroid than controls over the macula, but not the peripapillary regions. Thinner subfoveal choroid was associated with worsening exophthalmos and poorer vision. EDI-OCT can monitor choroidal vascular changes associated with TAO and its complications.

Analysis in Choroidal Thickness in Patients with Graves' Ophthalmopathy Using Spectral-Domain Optical Coherence Tomography

Objectives

The objective of the study is to observe changes in choroidal thickness (CT) in patients with Graves' ophthalmopathy using spectral-domain optical coherence tomography (SD-OCT).

Methods

The right eyes of 36 patients (27 females and 9 males) with Graves' ophthalmopathy (GO) and those of 36 age-, gender-, and diopter-level-matched healthy participants were evaluated. The patients' data were obtained within 3 months after the onset of Graves' disease (GD). Thyroid hormone levels and thyroid-stimulating hormone receptor antibody (TRAb) levels were measured, and the degree of exophthalmos was measured in all patients. Activity is measured by the clinical activity score (CAS). A horizontal scan centered on the fovea was performed in all participants. Five points of choroidal thickness were measured at the fovea (SFCT) and at 1500 μm nasal (N1500), 3000 μm nasal (N3000), 1500 μm temporal (T1500), and 3000 μm temporal (T3000) to the fovea.

Results

The CT measurements obtained were (mean ± SD) 313.47 ± 100.32 μm, 279.22 ± 85.80 μm, 214.64 ± 75.52 μm, 313.19 ± 80.36 μm, and 298.14 ± 82.75 μm in patients with GO and were 256.33 ± 50.18 μm, 223.14 ± 59.61 μm, 176.69 ± 60.66 μm, 250.92 ± 52.184 μm, and 239.47 ± 60.35 μm in the control group at the foveal, N1500, N3000, T1500, and T3000 measurement points, respectively. The CT in GO patients was significantly increased at all the points compared with the control group (P < 0.05). There was no relationship between the CT and CAS, the degree of exophthalmos, triiodothyronine (T3), tetraiodothyronine (T4), thyroid-stimulating hormone (TSH), or TRAb levels in GO.

Conclusions

CT was found to be increased in GO patients and had poor relationship with CAS, exophthalmos, and thyroid function tests.

The Increment of Choroidal Thickness in Euthyroid Graves' Ophthalmopathy: Is It an Early Sign of Venous Congestion?

Objective

Clinical manifestations of Graves' ophthalmopathy (GO) are caused by the overcompression of orbital tissues within the restricted orbital bone cavity. Impaired ocular blood flow may disrupt the retinal microstructure and functions. In this study, we aimed to investigate the macular and choroidal thickness changes in GO compared with healthy subjects.

Materials and Methods

The study group comprised 50 adult patients with previously diagnosed Graves' disease with ophthalmopathy who were on antithyroid treatment. For the assessment of GO activity, the VISA (vision, inflammation, strabismus, and appearance) inflammatory score was used. When euthyroidism was achieved without side effects, the patients were referred to the ophthalmology clinic for spectral-domain optical coherence tomography (SD-OCT) evaluation.

Results

Subfoveal, mean, and temporal choroidal thicknesses were increased significantly in the study group according to the controls. The mean choroidal thickness was elevated.

Conclusions

This elevation is because of the intraorbital inflammation even in this nonsevere GO group. Choroidal thickness might be affected from the venous obstruction and congestion in patients with GO. The elevation of the choroidal thickness might be an early sign of venous congestion that occurs before the elevation of intraocular pressure.

Choroidal Thickness in Patients with Graves' Ophthalmopathy

PURPOSE

The purpose of the study is to compare choroidal thickness (CT) in patients with active and inactive Graves' ophthalmopathy (GO) and that in healthy subjects by using spectral domain optical coherence tomography (SD-OCT).

METHODS

We conducted an observational, cross-sectional study of 28, 48, and 74 eyes of 14 patients with active GO (group 1), 24 patients with inactive GO (group 2), and 37 age-matched healthy subjects (group 3), respectively. Activity of GO was assessed by using initial clinical activity score (CAS). CT was measured by using SD-OCT. The differences in CT among the groups were compared, and the factors affecting subfoveal CT were analyzed.

RESULTS

The mean subfoveal CT was significantly greater in group 1 (395.84 ± 9.68 µm) than that in group 2 and group 3 (319.76 ± 7.07 µm and 314.22 ± 5.74 µm, respectively; p < 0.001) after adjusting for age, axial length, and intraocular pressure (IOP). Subfoveal CT was positively correlated with CAS (p < 0.001; r = 0.567). In multivariate analysis, thicker subfoveal CT was associated with younger age (p < 0.001; correlation coefficient B, -1.67; 95% CI, -2.57 to -0.78); disease activity (p < 0.001; correlation coefficient B, 95.28; 95% CI, 73.14-117.43); and lower IOP ((p < 0.001; correlation coefficient B, -4.09; 95% CI, -8.03 to -0.15).

CONCLUSIONS

To our knowledge, this is the first study showing that the mean subfoveal CT increases in patients with active GO. Subfoveal CT may be a useful parameter to monitor disease activity.

Ocular pulse amplitude as a diagnostic adjunct in giant cell arteritis

BACKGROUND

To develop an algorithm based on the ocular pulse amplitude (OPA) to predict the probability of a positive temporal artery biopsy (TAB) result in the acute phase of suspected giant cell arteritis (GCA).

METHODS

Unilateral TAB was performed and ipsilateral OPA measurements were taken by Dynamic Contour Tonometry. Among the clinical signs and laboratory findings tested in univariate analyses, OPA, Erythrocyte Sedimentation Rate (ESR) and thrombocyte count showed a strong association with a positive TAB result. Algorithm parameters were categorized into three groups (OPA >3.5, 2.5-3.5, and <2.5 mm Hg; ESR <25, 25-60, and >60 mm/h; thrombocyte count <250'000, 250'000-500'000, and >500'000/μl). Score values (0, 1, and 2) were attributed to each group, resulting in a total score range from 0 to 6. A univariate logistic regression analysis using the GCA diagnosis as the dependent and the total score as the independent variate was fitted and probability estimates were calculated.

RESULTS

Thirty-one patients with suspected GCA undergoing TAB during an eighteen-month observation period were enrolled. Twenty patients showed histologically proven GCA. Four patients had score values ≤2, fourteen between 3 and 4, and thirteen of ≥5. The corresponding estimated probabilities of GCA were<7, 52.6, and >95%.

CONCLUSION

The present study confirms previous findings of reduced OPA levels, elevated ESR, and elevated thrombocyte counts in GCA. It indicates that a sum score based on OPA, ESR, and thrombocyte count can be helpful in predicting TAB results, especially at the upper and the lower end of the sum score range.

The ocular pulse amplitude as a noninvasive parameter for carotid artery stenosis screening: a test accuracy study

PURPOSE

To investigate a potential correlation between the ocular pulse amplitude (OPA; i.e., the intraocular pressure difference between the systolic and diastolic phases of the heartbeat) and the severity of carotid artery stenosis (CAS) and to test its role as a screening parameter for CAS during routine ophthalmic examination.

DESIGN

Test accuracy study.

PARTICIPANTS

Patients referred for color duplex ultrasound examination of the extra- and intracranial cerebral arteries were enrolled consecutively.

METHODS

We measured OPA on both eyes by dynamic contour tonometry. Multivariate analyses were performed with risk factors for CAS (age, total cholesterol, low-density lipoprotein, and triglycerides) to compare the diagnostic value of OPA measurements with other non- or minimally invasive screening parameters.

MAIN OUTCOME MEASURES

The difference between OPA measurements in patients with no (<50%) and patients with severe CAS (>70%) as well as the value of OPA measurements to predict the severity of CAS taking further risk factors of CAS into consideration.

RESULTS

One hundred thirty-four eyes of 67 patients (25 women, 42 men) with a mean age of 67±13 years (range, 25-87) were included. The means of the OPA values of those patients showing no CAS (<50%) differed significantly (P = 0.036) from those with a stenosis of ≥70%. The multivariate model produced a statistically significant odds ratio (0.46; P = 0.007) for CAS of ≥70%.

CONCLUSIONS

The results of the present study provide proof of principle that the OPA is reduced in patients with CAS and may be used as a noninvasive, inexpensive, readily available, and unconfounded screening parameter to detect CAS and possibly to reduce the incidence of stroke.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any of the materials discussed in this article.

The ocular pulse amplitude at different intraocular pressure: a prospective study

PURPOSE

To investigate changes in ocular pulse amplitude (OPA) during a short-term increase in intraocular pressure (IOP) and to assess possible influences of biometrical properties of the eye, including central corneal thickness (CCT) and axial length.

METHODS

In a prospective, single centre study, OPA and IOP as measured by dynamic contour tonometry (DCT) were taken before baseline- and post-OPA (delta) intravitreal injection of 0.05 ml anti-vascular endothelial growth factor agents. Analysis was performed employing linear regression with baseline- and post (delta)-OPA differences as the dependent and post-IOP as well as delta IOP as the independent variable. A multilinear regression analysis with delta OPA as the dependent variable and baseline IOP, post-IOP, CCT and axial length as independent variables was conducted.

RESULTS

Forty eyes of 40 patients were included. IOP and OPA increased significantly after injection (IOP mean increase ± SD: 17.83 ± 9.83 mmHg, p < 0.001; OPA mean increase ± SD: 1.39 ± 1.16 mmHg, p < 0.001). For every mmHg increase in IOP, the OPA showed a linear increase of 0.05 mmHg (slope 0.05, 95% CI: 0.02-0.09, p = 0.003, r(2) = 0.20). Multiple regression analysis with delta OPA as the dependent variable revealed a partial correlation coefficient of 0.47 (p = 0.003) for post-IOP as the only significant contribution.

CONCLUSION

A clear positive relationship between OPA measurements and IOP levels was shown in a clinical routine setting using DCT focusing on baseline and postinterventional comparisons of OPA values after intravitreal injections in patients with exudative age related macular degeneration. When considering the OPA for diagnostic purposes, we recommend indication of corresponding IOP values.

Oxidative stress in patients with Graves' ophthalmopathy: relationship between oxidative DNA damage and clinical evolution

PURPOSE

To evaluate the relationship between oxidative stress and clinical evolution in patients with Graves' ophthalmopathy (GO).

METHODS

Thirty-one euthyroid GO patients and 25 healthy subjects participated in this study. Oxidative DNA damage was assessed by determination of the 8-hydroxy-2'-deoxyguanosine (8-OHdG) level in urine by ELISA. The relationship of oxidative DNA damage to the clinical evolutions of GO, especially the smoking status, clinical activity scores (CAS), and ophthalmopathy index was examined.

RESULTS

The mean 8-OHdG was significantly higher in GO patients than that of normal controls (12.6+/-5.7 vs 6.7+/-2.5 ng/mg creatinine, P<0.001). Smokers had significant higher 8-OHdG than did never smokers in GO patients (P=0.029), but not in healthy controls (P=0.374). Among GO patients, only CAS remained significantly correlated with 8-OHdG (P=0.001) after adjusting for age, sex, disease duration, the status of antithyroid drug and smoking, and thyroid-stimulating hormone level. Patients with active GO (CAS>3) had higher 8-OHdG than did the patients with CAS <or=3 (16.3+/-4.9 vs 8.6+/-3.0 ng/mg creatinine).

CONCLUSIONS

Our findings suggest that urinary 8-OHdG is increased in GO patients and is correlated with the disease activity. Smoking had a higher impact on the increased 8-OHdG among GO patients.

The clinical utility of dynamic contour tonometry and ocular pulse amplitude

PURPOSE

To determine if ocular pulse amplitude (OPA) as measured by dynamic contour tonometry (DCT) is related to severity of glaucoma, and if intraocular pressure (IOP) as measured by DCT is related to central corneal thickness (CCT).

METHODS

Patients were selected from the Duke Eye Center glaucoma clinic. Fifty-five eyes of 32 patients were included; right and left eyes were analyzed separately. CCT, OPA, DCT IOP, Goldmann applanation tonometry (GAT), Tonopen applanation tonometry (TAT), and systemic blood pressure were measured. Advanced Glaucoma Intervention Study score and mean deviation of visual field, and vertical and horizontal cup-disc ratios were recorded in a masked manner. Descriptive statistics were obtained, and OPA, DCT IOP, GAT, and TAT underwent univariate analyses to assess for relationships with predictor variables.

RESULTS

OPA, DCT IOP, GAT, and TAT were positively associated with CCT and with having no surgical intervention for right and left eyes, and were negatively associated with vertical and horizontal cup-disc ratios.

CONCLUSIONS

Increased OPA seems to correlate with less severe glaucoma and with increased CCT. DCT IOP seems to be affected by CCT along with GAT and TAT.

Increased retinal blood flow in patients with active Graves' ophthalmopathy

PURPOSE

To investigate retinal blood flow by Heidelberg retina flowmeter in patients with active Graves' ophthalmopathy.

MATERIALS AND METHODS

Thirty patients with active Graves' ophthalmopathy in euthyroid state and thirty normal controls were enrolled in this study. All subjects underwent heart rate, systolic and diastolic blood pressure detection, complete ophthalmological examination, Hertel's exophthalmometry, and retinal blood flow analysis by Heidelberg retina flowmeter. Patients additionally underwent automated threshold perimetry and extraocular muscle thickness measurement by A-scan ecography.

RESULTS

A significant statistical difference was found in exophthalmometry (P<0.001), intraocular pressure (P<0.001) and retinal blood flow (P<0.05) between patients and controls. In patients, muscle enlargement was significantly correlated with retinal blood flow (r=0.49, P=0.005) and proptosis (r=0.37, P=0.04). A significant positive correlation (r=0.52, P=0.002) was also found between intraocular pressure and proptosis.

CONCLUSIONS

Active Graves' ophthalmopathy patients present an increased retinal blood flow.

Technical note: How many readings are required for an acceptable accuracy in pulsatile ocular blood flow assessment?

PURPOSE

Pulsatile ocular blood flow (POBF) assessment aids the diagnosis of ocular diseases with defective ocular haemodynamics, such as glaucoma. Although each successful POBF measure given by the instrument represents five 'repeatable' pulses, there has been no study verifying how repeatable they are. There is also no report on the minimal number of measurements for an acceptable accuracy.

METHODS

Forty-three healthy young subjects were recruited and each subject had five consecutive POBF measurements obtained from one randomly selected eye. The coefficient of variation was calculated from the raw data of the five 'repeatable' pulses. The average from five consecutive measurements was considered as the standard for comparison with the first, average of the first two, the first three and the first four measurements. The 95% limits of agreement were determined using the Bland and Altman approach.

RESULTS

The coefficient of variation was greater than the manufacturer's claim of within 10%. The mean (+/-S.D.) POBF calculated from five consecutive measures was 732.5 +/- 243.2 microL min(-1). The mean (+/-S.D.) difference between the standard POBF and the first, average of the first two, the first three and the first four measurements was (in microL min(-1)): 12.5 +/- 59.8, 7.8 +/- 42.1, 9.6 +/- 32.5 and 3.7 +/- 19.6 respectively. The corresponding 95% limits of agreement were (in microL min(-1)): +/-117.2, +/-82.6, +/-63.8 and +/-38.4 respectively.

CONCLUSIONS

As the five 'repeatable' pulses were not as repeatable as the manufacturer claims, practitioners should not rely on one single POBF measure. An average of three consecutive measurements will be adequate to detect the minimum reported difference in POBF between glaucoma and normal patients.

Pulsatile ocular blood flow change after treatment with systemic steroid in patients with Graves' ophthalmopathy

PURPOSE

Our previous study has demonstrated an impairment of pulsatile ocular blood flow (POBF) in patients with Graves'ophthalmopathy (GO). Here we further evaluate the haemodynamic change in GO patients after systemic steroid.

METHODS

In a prospective, interventional, consecutive clinical case series, all patients with active and moderately severe GO who underwent systemic steroid treatment were evaluated. The change of POBF and the clinical activity and severity of the disease were assessed.

RESULTS

In total, 11 patients underwent intravenous methylprednisolone pulse therapy followed by 2-month oral prednisolone therapy. POBF improved from a mean value of 476.5 to 614.7 microl/min (P<0.001) after treatment. Likewise, the mean clinical activity score reduced from 4.8 to 1.6. However, systemic steroid had less effect on the severity of GO. It also revealed that there is a greater improvement of POBF in those with more clinical activity score (>4) at the onset.

CONCLUSIONS

Following treatment with systemic steroid we have demonstrated a significant improvement in POBF in patients with GO.