Nailfold Capillaroscopy of Resting Peripheral Blood Flow in Exfoliation Glaucoma and Primary Open-Angle Glaucoma

Differences in Systemic Pulse Waveform Between Individuals With Glaucoma, Glaucoma Suspects, and Healthy Controls

Purpose

It has been hypothesized that compromised ocular circulation in glaucoma may be concomitant of systemic changes. The purpose of this study is to test whether systemic blood flow pulse waveform patterns differ between individuals with glaucoma (GL), glaucoma suspects (GLS), and normal healthy controls (HC).

Methods

The study included 35 bilateral GL, 67 bilateral GLS, 29 individuals with unilateral GL who were considered GLS in the other eye, and 44 healthy controls. Systemic pulsatile blood pressure waveforms were recorded using a finger cuff. A continuous 200 Hz plethysmography recording is made to obtain a pulse waveform. Waveform parameters were extracted using custom software from an average of eight pulse cycles. These were compared between GL, GLS, and HC groups on a per-eye basis, using generalized estimating equation models to account for intereye correlations; and plotted against disease severity by visual field linearized mean deviation (MDlin) and retinal nerve fiber layer thickness (RNFLT).

Results

Averaged blood pressure was significantly lower in the HC group (mean ± standard deviation 91.7 ±11.7 mm Hg) than the GLS (102.4 ± 13.9) or GL (102.8 ± 13.7) groups, with P < 0.0001 (generalized estimating equation regression). Waveform parameters representing vascular resistance were higher in both GLS and GL groups than the HC group; and were correlated with RNFLT and MDlin (P ≤ 0.05).

Conclusions

The shape of the systemic pulsatile waveform differs in individuals with GL/GLS suspects, compared to HC eyes. Blood pressure changes more rapidly in individuals with GL, which suggests higher arterial stiffness.

Association between Diabetes and Exfoliation Syndrome

Topic

This systematic review and meta-analysis summarizes the existing evidence for the association of diabetes mellitus (DM) and exfoliation syndrome (XFS).

Clinical Relevance

Understanding and quantifying these associations may aid clinical guidelines or treatment strategies and shed light on disease pathogenesis. The role of DM in determining XFS risk may also be of interest from an individual or public health perspective.

Methods

The study protocol was preregistered on the International Prospective Register of Systematic Reviews with registration number CRD42023429771. We systematically searched PubMed and Embase from inception to June 15, 2023. Screening and full-text review were conducted by 2 independent reviewers. All observational studies reporting an age-adjusted odds ratio (OR) and 95% confidence interval (CI) for the association between DM and XFS among adults were included. Quantitative synthesis involved a random-effects meta-analysis using the DerSimonian-Laird method to generate a pooled OR. Risk of bias was evaluated using the Newcastle-Ottawa Scale.

Results

Fourteen studies (9 cross-sectional and 5 case-control) comprising 47 853 participants were included in the systematic review and meta-analysis. Random-effects meta-analysis indicated no overall association between DM and XFS (OR 0.94; 95% CI, 0.73–1.21; I 2  = 68.5%). However, subgroup analysis revealed a significant inverse association among individuals ≥ 65 years (OR 0.71; 95% CI, 0.54–0.93) versus individuals < 65 years (OR 1.22; 95% CI, 0.80–1.87; P effect modification  = 0.04). The relation between DM and XFS was also inverse in case-control studies (OR 0.75; 95% CI, 0.58–0.97) but was nonsignificant in cross-sectional studies (OR 1.17; 95% CI, 0.83–1.66; P effect modification  = 0.04). Overall risk of bias was low, with tests for publication bias showing P  ≥ 0.06.

Conclusion

This meta-analysis suggests no association between DM and XFS overall, with possible inverse associations of DM with XFS in older populations. However, given the substantial heterogeneity and borderline significance for publication bias, these findings should be interpreted with caution. Our results give insight into the unique etiology and clinical relevance of XFS while proposing the need for larger longitudinal and genetic biomarker studies.

Financial Disclosure(s)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Involvement of the systemic microcirculation in pediatric uveitis

BACKGROUND

Pediatric uveitis is a severe inflammatory ocular condition that can lead to sight-threatening complications and can negatively impact quality of life. The retinal microcirculation is often affected in intermediate uveitis and panuveitis. Here, we examined the extraocular (i.e., systemic) microcirculation in pediatric uveitis cases and healthy controls using nailfold capillaroscopy (NFC).

METHODS

We performed NFC in 119 children with noninfectious uveitis and 25 healthy pediatric controls, and assessed the following parameters: capillary density (number of capillaries/mm), dilated capillaries (apex > 20 µm), avascular area, the presence of microhemorrhages, and capillary morphology. Differences in NFC parameters between cases and controls were calculated using regression analysis after adjusting for age and sex.

RESULTS

The mean (± SD) age of the patient group was 13.7 (± 3) years, with 56% females; 46%, 18%, and 36% of cases presented as anterior uveitis, intermediate uveitis, and panuveitis, respectively, with an overall mean disease duration of 4.7 (± 4.0) years. Compared to the control group, the pediatric uveitis cases had a significantly higher number of dilated capillaries/mm and a higher prevalence of ramified capillaries. Moreover, compared to the control group the intermediate uveitis cases had a significantly higher number of dilated capillaries, whereas the anterior uveitis cases had a lower capillary density and a higher prevalence of ramified capillaries.

CONCLUSIONS

Children with uveitis without systemic disease can present with changes in systemic microcirculation. These changes vary amongst the subtypes of uveitis.

The Differences in the Pattern of OCT and OCTA Examinations between Early Normal- and High-Tension Pseudoexfoliative Glaucoma

Purpose. The aim of this study was to compare the results of optical coherence tomography angiography (OCTA) and optical coherence tomography (OCT) examinations in patients with normal-tension glaucoma (NTG) in comparison to high-tension pseudoexfoliative glaucoma (HTG) patients at the early stage of glaucoma. Material and methods. The studied groups consisted of patients in the early stage of NTG (70 eyes) and the early stage of HTG (71 eyes). In NTG and HTG groups, a detailed ophthalmic examination was performed. Optic disc OCT with peripapillary RNFL measurements and OCTA examination with the evaluation of the macula and optic disc were performed for all participants using Zeiss Cirrus 5000. Results. NTG and HTG groups were statistically similar as far as the MD was concerned, and both groups had early glaucoma. When evaluating the RNFL thickness, the only statistical difference between early NTG and HTG was observed in the thicknesses in the temporal sector of peripapillary RNFL, with thinner values in the NTG group (53.94 vs. 59.94, p = 0.0071). When the OCTA results of the macula and optic disc were evaluated, there were no statistical differences between early NTG and HTG. Conclusions. The vascular density and flow parameters assessed in OCTA were equal between early NTG and HTG, and therefore the involvement of vascular factors in NTG pathogenesis could not be confirmed. Our results confirm the preponderance of more frequent temporal RNFL involvement in early NTG.

Vasoreactivity of the optic nerve head, nailfold, and facial skin in response to cold provocation in normal-tension glaucoma patients

BACKGROUND

The dysfunction of optic nerve head (ONH) hemodynamics has been suggested to be involved in the pathogenesis of normal-tension glaucoma (NTG). The aim of this study was to compare vasoreactivity in the ONH, nailfold, and facial skin in response to cold-water provocation in NTG patients and healthy controls.

METHODS

We performed cold-water provocation in 14 eyes of 14 NTG patients and 15 eyes of 15 age-matched control subjects. Laser speckle flowgraphy-derived tissue-area mean blur rate (MT), skin blood flowmetry-derived pulse wave amplitude (PA), nailfold capillaroscopy-derived nailfold capillary diameter, and other clinical parameters were recorded at baseline and 4 and 6 min after the cold stimulus. We compared changes (as percentages) in these variables in the NTG and control subjects with a linear mixed-effects model and evaluated correlations between these changes with Spearman's rank correlation coefficient.

RESULTS

The interaction term between the NTG group (reference, control group) and the 4-min protocol step (reference, baseline) significantly affected the changes in MT, nailfold capillary diameter and PA (β = -9.51%, P = 0.017, β = -20.32%, P = 0.002; β =  + 18.06%, P = 0.017, respectively). The change in MT was positively correlated with the change in nailfold capillary diameter, and negatively correlated with the change in PA (r = 0.39, P = 0.036; r = -0.40, P = 0.031, respectively).

CONCLUSION

NTG patients showed abnormal vasoconstriction in the ONH and nailfold and vasodilation in the facial skin in response to cold-water provocation.

Peripheral Microvascular Abnormalities Associated with Open-Angle Glaucoma

PURPOSE

To investigate peripheral microvascular abnormalities associated with patients with open-angle glaucoma (OAG).

DESIGN

This was a cross-sectional study.

PARTICIPANTS

Patients with OAG and controls.

METHODS

All subjects underwent detailed ophthalmic evaluation, including Humphrey visual field (HVF) tests and swept source OCT. To evaluate peripheral microvascular abnormalities, nailfold capillaroscopy (NFC) and laser Doppler imaging (LDI) were performed. The presence of microhemorrhages, tortuous capillaries, dilated capillaries, avascular areas, and the capillary density, among other characteristics, were recorded using NFC; fingertip blood flow (FBF) was measured using LDI at different time points, before and 1, 10, and 20 minutes after exposure to a cold stimulus. In addition, venous blood samples were collected to measure serum endothelin-1 (ET-1) concentrations as well as serum autoantibodies.

MAIN OUTCOME MEASURES

Presence of microhemorrhages, tortuous capillaries, and dilated capillaries; FBF; ET-1; and autoantibodies.

RESULTS

Sixty-eight subjects (43 patients with OAG and 25 controls) were enrolled in the study. Microhemorrhages were found in the nail bed of 65.1% of the patients with OAG compared with 25.0% of the controls (P = 0.003). There was a significant difference in the mean FBF at the baseline in patients with OAG versus controls (293.6 ± 100.2 vs 388.8 ± 52.0 perfusion units, respectively, P < 0.001), together with a significant decrease in the mean FBF 10 and 20 minutes after cold stimulus in patients with OAG in comparison to controls (P < 0.001 for all comparisons). There was a positive correlation between mean baseline FBF and HVF mean deviation (r = 0.27, P = 0.03) and between mean baseline FBF and average retinal nerve fiber layer thickness (r = 0.44, P = 0.001). Neither the analysis of ET-1 concentrations (P= 0.71) nor the autoantibodies measurements (P > 0.05, for all) showed any difference between the 2 groups.

CONCLUSIONS

Significant peripheral microvascular abnormalities were found in patients with OAG compared to controls, suggesting that microvascular changes might play a role in the pathogenesis of the disease. In addition, part of these peripheral microvascular abnormalities seems to be correlated with both functional and structural glaucomatous damage.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Results of Nailfold Videocapillaroscopy in Patients with Pseudoexfoliative Glaucoma

The aim of this study was to evaluate the nailfold videocapillaroscopic examination results from patients with pseudoexfoliative glaucoma (XFG) and to assess the relationship between the results of this examination and the patient's clinical status in the XFG group.

MATERIAL AND METHODS

The studied group consisted of 39 Caucasian patients with XFG and 32 patients in a control group. The patients were classified into two subgroups: the hypertensive pseudoexfoliative glaucoma (hXFG) subgroup and the normotensive pseudoexfoliative glaucoma (nXFG) subgroup. The nailfold videocapillaroscopy (NVC) was performed on all participants. The results of each NVC were classified as having a normal or abnormal pattern.

RESULTS

There was no statistical difference between the results of an abnormal NVC pattern in the study group vs. the control group (p = 0.8773). Microhemorrhages were shown in 30.0% of patients with nXFG vs. the control group (6.25%) (p = 0.0520). Microhemorrhages tended to be more frequent in the XFG group (p = 0.1221). A prevalent number of tortuous capillaries was observed in hXFG patients with advanced glaucomatous neuropathy. Dilatation in the capillaries and microbleedings were observed in the group of patients with lower IOP values. Tortuosity in the capillaries was significantly more frequent in PEXG patients (XFG vs. control: p = 0.0386). No relationships between the results of NVC and age, c/d, BCVA, time of treatment, and visual field defect were found.

CONCLUSIONS

Specific features of NVC examination differentiate nXFG from hXFG patients. Some capillaroscopic features may correlate with the patient's clinical status of XFG.

Vascular parameters and endothelin-1 measurements in glaucoma patients with low- and high-tension optic disc hemorrhages

This prospective study aimed to compare vascular parameters (endothelin-1 [ET-1] blood levels, laser Doppler imaging [LDI] of distal phalanxes, and nailfold capillaroscopy) between open-angle glaucoma patients with low- and high-tension optic disc hemorrhages (LTDH and HTDH, respectively). The 33 enrolled patients (mean age, 62.3 ± 13 years) were classified as LTDH or HTDH if they presented at the time of DH detection an intraocular pressure (IOP) < 16 mmHg or ≥ 16 mmHg, respectively. Demographic and ophthalmological data, ET-1 concentrations, LDI (before and 1, 10, and 20 min after cold stimulation), and nailfold capillaroscopy findings were evaluated. The ET-1 blood level was 65% higher in the LTDH (2.27 ± 1.46 pg/ml) than in the HTDH (1.37 ± 0.57 pg/ml; p = 0.03) group. Moreover, there was a statistically significant negative correlation between ET-1 blood concentration and IOP at the time of DH detection (r = -0.45, p = 0.02). Blood flow measurements 10 and 20 min after cold stimulation were lower in the LTDH group than in the HTDH group (p < 0.01). Patients developing DH with lower IOPs have higher ET-1 blood levels and more peripheral vascular dysfunction as estimated by LDI than those with higher IOPs. These findings suggest that distinct underlying mechanisms may be involved in patients developing DH within different IOP ranges.

Age of Rats Affects the Degree of Retinal Neuroinflammatory Response Induced by High Acute Intraocular Pressure

Purpose

To investigate whether retinal neuroinflammatory response was affected by aging in a rat model of acute glaucoma.

Methods

Young adult and aged rats were randomly assigned into normal control, 45 mmHg, 60 mmHg, and 90 mmHg groups. Intraocular pressure (IOP) of rats was acutely elevated to 45 mmHg, 60 mmHg, and 90 mmHg, respectively. Three days after high IOP treatment, loss of retinal ganglion cells (RGCs), formation of proinflammatory microglia/macrophages and neurotoxic astrocytes, and deposition of complement C3 in the retina were detected by immunofluorescence. ELISA was used to assess the protein levels of proinflammatory cytokines TNF and IL-1β in the retina.

Results

Compared with young adult retinae, (1) loss of RGCs was more severe in aged retinae under the same IOP treatment, (2) microglia/macrophages were more prone to adopt proinflammatory phenotype in aged retinae in response to elevated IOP, (3) high IOP treatment induced astrogliosis, formation of neurotoxic astrocytes, and deposition of complement C3 more easily in aged retinae, and (4) aged retinae induced higher levels of proinflammatory cytokines TNF and IL-1β under the same IOP treatment.

Conclusion

Our data indicated that aging affects the degree of retinal neuroinflammatory response initiated by ocular hypertension, which may contribute to the age-related susceptibility of RGCs to elevated IOP.

Relationship between peripheral vasospasm and visual field progression rates in patients with normal-tension glaucoma with low-teen intraocular pressure

Purpose

To investigate the association between peripheral vasospasm and the visual field (VF) progression rate in patients with normal-tension glaucoma (NTG) with low-teen intraocular pressure (IOP).

Methods

The finger temperature of 113 NTG patients was measured before and after exposure to ice water using a Temperature gun (cold pressor test). These patients had confirmed VF progression, despite a low-teen IOP during a follow-up period of >5 years. VF progression rates were calculated as the slope of the visual field index (VFI) and mean deviation (MD) over time. Demographic, systemic, and ocular factors and VF progression rates were compared, based on the cold pressor test results. A regression analysis was used to investigate the factors affecting VF progression rates.

Results

Mean age, initial IOP, mean IOP during the follow-up period, and initial VF MD were 57.1 years, 15.8 mmHg, 12.0 mmHg, and -5.2 dB, respectively. When patients were divided into two groups (less vasospasm and more vasospasm) according to changes in temperature after exposure to ice water, the VF progression rate was significantly faster in the group with more vasospasm. In a multiple regression analysis, older age, worse initial VF MD, and greater decrease in finger temperature after ice water exposure were significantly associated with faster VF progression rates.

Conclusion

An excessive drop in finger temperature after exposure to ice water was significantly associated with faster VF progression in patients with low-teen NTG. This suggests that the blood flow in the optic nerve head may also be disturbed by peripheral vasospasm, accelerating glaucomatous damage regardless of IOP.

Association of Nailfold Capillary Abnormalities With Primary Open-angle Glaucoma and Glaucomatous Visual Field Loss

PRECIS

Nailfold capillary abnormalities are associated with primary open-angle glaucoma (POAG) and increased severity of global and central glaucomatous visual field (VF) loss.

PURPOSE

The purpose of this study was to investigate whether nailfold capillary abnormalities are associated with POAG and the severity of glaucomatous VF loss.

MATERIALS AND METHODS

A cross-sectional study of 83 POAG cases and 40 controls was conducted. Nailfold capillaroscopy images were assessed by masked graders for dilated capillaries >50 μm, crossed capillaries, tortuous capillaries, hemorrhages, avascular zones >100 μm, capillary density, and capillary distribution. VF loss in glaucoma cases was quantified using mean deviation and mean central pattern standard deviation (PSD) from the worst-affected eye.

RESULTS

Logistic regression analyses of cases and controls showed that avascular zones [odds ratio (OR)=1.24; 95% confidence interval (CI): 1.06, 1.47; P=0.005], capillary density (OR=0.63; 95% CI: 0.46, 0.83; P<0.001), and capillary distribution (OR=7.88; 95% 95% CI: 2.53, 28.40; P=0.001) were associated with POAG. Simple linear regression analysis of cases only showed that nailfold hemorrhages were associated with mean deviation (β=-5.10; 95% CI: -9.20, -1.01; P=0.015) and mean central PSD (β=-4.37; 95% CI: -8.18, -0.57; P=0.025), and this remained significant in the multiple linear regressions. After controlling for demographic and clinical factors, avascular zones were associated with both mean deviation (β=-0.76; 95% CI: -1.48, -0.04; P=0.040) and mean central PSD (β=-0.78; 95% CI: -1.45, -0.10; P=0.024), whereas capillary distribution was only associated with mean deviation (β=-4.67; 95% CI: -7.92, -1.43; P=0.017).

CONCLUSION

Nailfold capillary abnormalities are associated with POAG as well as increased global and central vision loss.

Nailfold capillaroscopy : a comprehensive review on common findings and clinical usefulness in non-rheumatic disease

Nailfold video-capillaroscopy (NVC) is a useful diagnostic tool, used to early detect abnormalities in micro-circulation, providing a qualitative description of microvascular anomalies in Raynaud's phenomenon. NVC role in the diagnosis of Systemic Sclerosis is well known. In other rheumatic conditions such as connective tissue diseases, vasculitis, and arthritis, the NVC anomalies are often included in a scleroderma like pattern. The use of NVC in non-rheumatic diseases (NRD), with remarkable microvascular damage, as diabetes, is not standardized yet, although several research studies are carrying on. The aim of this article is to provide a resume of published results in order to lay the groundwork for the employment of NVC both in the diagnosis and follow up of microvascular complication in NRD. Furthermore, we mention NVC findings in pathologies without well recognize microvascular damages in their pathogenesis : micro-vessels abnormalities may suggest a different point of view. J. Med. Invest. 68 : 6-14, February, 2021.

The Relationship Between Nailfold Microcirculation and Retinal Microcirculation in Healthy Subjects

Objective

To evaluate whether the nailfold microcirculation is associated with retinal microcirculation in healthy subjects.

Methods

Fifty subjects without systematic and ocular diseases were enrolled. Thickness of peripapillary retinal nerve fiber layer (RNFL), vessel density (VD) of radial peripapillary capillaries (RPCs), and superficial capillary VD in macular zone were measured with optical coherence tomography angiography (OCTA) in left eyes. Nailfold microcirculation, including capillary density, avascular zones, dilated capillaries, and hemorrhages was examined on the fourth digit of each subject’s non-dominant (left) hand with nailfold capillaroscopy (NFC).

Results

After adjustment for relatively systemic factors, multivariate regression analyses showed a significant direct relationship between RNFL thickness and nailfold capillary density (OR = 1.09; p = 0.046). RNFL thickness and RPCs VD were negatively correlated with nailfold avascular zones (OR = 0.855; p = 0.007; OR = 0.596; p = 0.010). Superficial VD of parafovea was negatively associated with dilated nailfold capillaries (OR = 0.794; p = 0.012).

Conclusion

In healthy subjects, nailfold capillary lower density and abnormalities are associated with reduced RNFL thickness and retinal VD. The results provide a theoretical foundation for relevant studies on ocular diseases with microvascular abnormalities and could contribute to pathogenesis understanding in the future. NFC and OCTA have the potential to identify risk factors and improve accuracy of the early diagnosis and treatment of ocular diseases, even systemic diseases with any microvascular component in clinical practice.

Clinical Trail Registration

http://www.chictr.org.cn/index.aspx, identifier ChiCTR 1800017875.

Ocular blood flow as a clinical observation: Value, limitations and data analysis

Alterations in ocular blood flow have been identified as important risk factors for the onset and progression of numerous diseases of the eye. In particular, several population-based and longitudinal-based studies have provided compelling evidence of hemodynamic biomarkers as independent risk factors for ocular disease throughout several different geographic regions. Despite this evidence, the relative contribution of blood flow to ocular physiology and pathology in synergy with other risk factors and comorbidities (e.g., age, gender, race, diabetes and hypertension) remains uncertain. There is currently no gold standard for assessing all relevant vascular beds in the eye, and the heterogeneous vascular biomarkers derived from multiple ocular imaging technologies are non-interchangeable and difficult to interpret as a whole. As a result of these disease complexities and imaging limitations, standard statistical methods often yield inconsistent results across studies and are unable to quantify or explain a patient's overall risk for ocular disease. Combining mathematical modeling with artificial intelligence holds great promise for advancing data analysis in ophthalmology and enabling individualized risk assessment from diverse, multi-input clinical and demographic biomarkers. Mechanism-driven mathematical modeling makes virtual laboratories available to investigate pathogenic mechanisms, advance diagnostic ability and improve disease management. Artificial intelligence provides a novel method for utilizing a vast amount of data from a wide range of patient types to diagnose and monitor ocular disease. This article reviews the state of the art and major unanswered questions related to ocular vascular anatomy and physiology, ocular imaging techniques, clinical findings in glaucoma and other eye diseases, and mechanistic modeling predictions, while laying a path for integrating clinical observations with mathematical models and artificial intelligence. Viable alternatives for integrated data analysis are proposed that aim to overcome the limitations of standard statistical approaches and enable individually tailored precision medicine in ophthalmology.

Nailfold capillary morphology and platelet function in patients with exfoliative glaucoma

Purpose

The purpose of the present study was to evaluate the nailfold capillary morphological features in patients with exfoliative glaucoma (XFG) and compare them with those pertaining to primary open-angle glaucoma (POAG), normal controls and subjects with exfoliation syndrome (XFS). The second purpose was to investigate all parameters related to platelet function on the hemogram, including the platelet count (PLT), the mean platelet volume (MPV), platelet distribution width (PDW), and plateletcrit (PCT) in patients with XFG. These parameters were subsequently compared with those belonging to normal controls, POAG and XFS subjects.

Methods

This case control study involved 152 consecutive patients that were examined at the Glaucoma Department of Clinic for Eye Diseases, Clinical Centre of Serbia, as the referral center for glaucoma in Serbia, between June 2016 and December 2017.

Results

Regarding capillaroscopic characteristics, statistically significant difference was found in capillary diameter and tortuosity between the XFG and POAG group (p = 0.050 and p = 0.035) and the XFG and NC group (p = 0.003 and p = 0.044), as well as in the distribution of capillary loops and avascular zones between the XFG and NC group (p = 0.014 and p = 0.004). The subjects with XFG had lower PLT values compared to POAG patients (p = 0.022).

Conclusions

In conclusion, to the best of our knowledge, this study marks the first attempt to evaluate capillary morphology as well as to investigate all parameters related to platelet function on the hemogram, in patients with newly diagnosed XFG. Our findings revealed nailfold capillary morphological vascular changes in XFG patients. The subjects with XFG had lower PLT values and a higher MPV serum parameter compared to normal controls and patients with POAG. Further research in this field should therefore aim to evaluate the consequences of the aforementioned microvascular abnormalities in patients with XFG.