Normotensive Glaucoma and Risk Factors in Normotensive Eyes With Pseudoexfoliation Syndrome

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.

Characteristic Differences between Normotensive and Hypertensive Pseudoexfoliative Glaucoma

PURPOSE

To compare the differences between eyes with pseudoexfoliative glaucoma (PXG) when they are divided into two groups (hypertensive PXG and normotensive PXG) according to the intraocular pressure (IOP).

METHODS

This is a retrospective study. Data from 86 hypertensive PXG eyes and 80 normotensive PXG eyes were included. Hypertensive PXG was defined as PXG with IOP ≥ 22 mmHg, and normotensive PXG was defined as with IOP ≤ 21 mmHg). Central corneal thickness (CCT) was measured by ultrasound pachymetry. Lamina cribrosa thickness (LT) was evaluated using swept-source optical coherence tomography.

RESULTS

No significant differences were observed between hypertensive and normotensive PXG in terms of age, gender, axial length, hypertension, or diabetes. Normotensive PXG eyes had thinner CCT than hypertensive PXG eyes (p = 0.02). To compare LT, a sub-analysis was performed after matching age, VF MD and retinal nerve fiber layer thickness. The normotensive PXG group (n = 32) demonstrated significantly thinner LT compared with the hypertensive PXG group (n = 32) at similar ages and levels of glaucoma severity (p < 0.001).

CONCLUSIONS

Eyes with normotensive PXG demonstrated thinner CCT and LT compared with those with hypertensive PXG, suggesting structural vulnerability to glaucoma.

Ocular pulse amplitude (OPA) in canine ADAMTS10-open-angle glaucoma (ADAMTS10-OAG)

Introduction: The role of ocular rigidity and biomechanics remains incompletely understood in glaucoma, including assessing an individual's sensitivity to intraocular pressure (IOP). In this regard, the clinical assessment of ocular biomechanics represents an important need. The purpose of this study was to determine a possible relationship between the G661R missense mutation in the ADAMTS10 gene and the ocular pulse amplitude (OPA), the difference between diastolic and systolic intraocular pressure (IOP), in a well-established canine model of open-angle glaucoma (OAG). Methods: Animals studied included 39 ADAMTS10-mutant dogs with different stages of OAG and 14 unaffected control male and female dogs between 6 months and 12 years (median: 3.2 years). Dogs were sedated intravenously with butorphanol tartrate and midazolam HCl, and their IOPs were measured with the Icare® Tonovet rebound tonometer. The Reichert Model 30™ Pneumotonometer was used to measure OPA. Central corneal thickness (CCT) was measured via Accutome® PachPen, and A-scan biometry was assessed with DGH Technology Scanmate. All outcome measures of left and right eyes were averaged for each dog. Data analysis was conducted with ANOVA, ANCOVA, and regression models. Results: ADAMTS10-OAG-affected dogs displayed a greater IOP of 23.0 ± 7.0 mmHg (mean ± SD) compared to 15.3 ± 3.6 mmHg in normal dogs (p < 0.0001). Mutant dogs had a significantly lower OPA of 4.1 ± 2.0 mmHg compared to 6.5 ± 2.8 mmHg of normal dogs (p < 0.01). There was no significant age effect, but OPA was correlated with IOP in ADAMTS10-mutant dogs. Conclusion: The lower OPA in ADAMTS10-mutant dogs corresponds to the previously documented weaker and biochemically distinct posterior sclera, but a direct relationship remains to be confirmed. The OPA may be a valuable clinical tool to assess ocular stiffness and an individual's susceptibility to IOP elevation.

The Inflammasome-Dependent Dysfunction and Death of Retinal Ganglion Cells after Repetitive Intraocular Pressure Spikes

The dysfunction and selective loss of retinal ganglion cells (RGCs) is a known cause of vision loss in glaucoma and other neuropathies, where ocular hypertension (OHT) is the major risk factor. We investigated the impact of transient non-ischemic OHT spikes (spOHT) on RGC function and viability in vivo to identify cellular pathways linking low-grade repetitive mechanical stress to RGC pathology. We found that repetitive spOHT had an unexpectedly high impact on intraocular homeostasis and RGC viability, while exposure to steady OHT (stOHT) of a similar intensity and duration failed to induce pathology. The repetitive spOHT induced the rapid activation of the inflammasome, marked by the upregulation of NLRP1, NLRP3, AIM2, caspases -1, -3/7, -8, and Gasdermin D (GSDMD), and the release of interleukin-1β (IL-1β) and other cytokines into the vitreous. Similar effects were also detected after 5 weeks of exposure to chronic OHT in an induced glaucoma model. The onset of these immune responses in both spOHT and glaucoma models preceded a 50% deficit in pattern electroretinogram (PERG) amplitude and a significant loss of RGCs 7 days post-injury. The inactivation of inflammasome complexes in Nlrp1-/-, Casp1-/-, and GsdmD-/- knockout animals significantly suppressed the spOHT-induced inflammatory response and protected RGCs. Our results demonstrate that mechanical stress produced by acute repetitive spOHT or chronic OHT is mechanistically linked to inflammasome activation, which leads to RGC dysfunction and death.

Choroidal thickness measurements of subjects with pseudoexfoliative syndrome and pseudoexfoliative glaucoma: A contralateral eye study

AIM

In this study, we aimed to investigate the peripapillary choroidal thickness (PPCT) and macular choroidal thickness (MCT) in pseudoexfoliation (PEX) syndrome and compare the data of the contralateral eyes according to the presence of biomicroscopic eye involvement and glaucoma.

METHOD

In this cross-sectional case-control study, PPCT and MCT measurements were analyzed in 162 eyes of 81 subjects with PEX syndrome, diagnosed biomicroscopically with the detection of PEX material. The sample included 63 eyes with pseudoexfoliation glaucoma (PG), 49 eyes with visible PEX material alone without glaucoma (PM), 50 fellow eyes without biomicroscopically visible PEX material (F), and 48 eyes of 24 healthy individuals (controls) without any sign of PEX in the detailed ophthalmologic examination. The PEX syndrome group consisted of 25 PM-F, 25 PG-F, 19 PG-PG, and 12 PM-PM eye pairs. The PPCT and MCT values were compared between the eye-pairs of the subjects with the PEX syndrome.

RESULTS

The mean PPCT measurements were 183.3 ± 8.1 µm, 158.5 ± 5.4 µm, 167.8 ± 5.9 µm, and 149.9 ± 5.5 µm for the eyes in the control, F, PM, and PG groups, respectively. The eyes in the PG group had statistically significantly lower measurements than those in the control group (p < 0.01). In the contralateral eye comparison of the subjects with PEX syndrome, no significant difference was found in relation to the mean PPCT and MCT measurements between the PM-F, PG-F, and PG-PG eye pairs (p > 0.05 for all).

CONCLUSION

Although the eye groups with PEX syndrome had lower mean PPCT measurements than the controls, the contralateral eye analysis of the asymmetrically involved eye pairs showed no significant differences.

Lack of association between SIX1/SIX6 locus polymorphisms and pseudoexfoliation syndrome in a population from the Republic of Korea

Previous studies have reported the association of the SIX1/SIX6 locus with open-angle glaucoma in various ethnic populations. However, the relevance of the SIX1/SIX6 locus to pseudoexfoliation syndrome (XFS) appears uncertain at present. Thus, we investigated the relationship between polymorphisms in the SIX1/SIX6 locus and XFS in a Korean XFS cohort. A total of 246 participants comprising 167 unrelated Korean patients with XFS and 79 ethnically matched control subjects were recruited. Four polymorphisms of the SIX1/SIX6 locus (rs33912345, rs12436579, rs2179970, and rs10483727) were genotyped using a TaqMan® allelic discrimination assay. Genotypic and allelic associations were analyzed using logistic regression. The minor allele frequency (MAF) of rs33912345 was found to be 0.287 and 0.247 in the XFS cases and controls, respectively, and the MAF of rs12436579 was found to be 0.383 and 0.361 in the XFS cases and control subjects, respectively. The MAF of rs2179970 was found to be 0.090 and 0.095 in the XFS cases and control subjects, respectively, and the MAF of rs10483727 was found to be 0.293 and 0.253 in the XFS cases and control subjects, respectively. Genetic association analysis of 4 SIX1/SIX6 locus single nucleotide polymorphisms (SNPs) revealed no significant difference in genotype distribution between the XFS cases and control subjects in the allelic, dominant, or recessive models (all, P > .05). The current study suggested that SIX1/SIX6 locus polymorphisms (rs33912345, rs12436579, rs2179970, and rs10483727) may not be associated with a genetic susceptibility to XFS in a Korean cohort.

Small Nucleolar RNAs in Pseudoexfoliation Glaucoma

Small nucleolar RNAs (snoRNAs) are small non-coding regulatory RNAs that have been investigated extensively in recent years. However, the relationship between snoRNA and glaucoma is still unknown. This study aims to analyze the levels of snoRNA expression in the aqueous humor (AH) of patients with pseudoexfoliation glaucoma (PEXG) compared to a control group and identify hypothetical snoRNA-dependent mechanisms contributing to PEXG. The AH was obtained from eighteen Caucasian patients, comprising nine PEXG and nine age-matched control patients. RNA was isolated, and a microarray system was used to determine the snoRNA expression profiles. Functional and enrichment analyses were performed. We identified seven snoRNAs, SNORD73B, SNORD58A, SNORD56, SNORA77, SNORA72, SNORA64, and SNORA32, in the AH of the PEXG and control group patients. Five snoRNAs showed statistically significantly lower expression in the PEXG group, and two snoRNAs had statistically significantly higher expression in the PEXG group compared to the control group. In addition, we identified two factors-CACNB3 for SNORA64 and TMEM63C for SNORA32, similar to PEX-related genes (CACNA1A and TMEM136). The enrichment analysis for four genes targeted by snoRNAs revealed possible mechanisms associated with glaucoma and/or PEX, but the direct role of snoRNAs in these biological processes was not proven.

Association of Epiretinal Membrane With Pseudoexfoliation Glaucoma and Long-term Factors Affecting Visual Function

PRCIS

Epiretinal membrane (ERM) tended to deteriorate more in pseudoexfoliation eyes with than without glaucoma. Incremental change in central macular thickness (CMT) induced by ERM deterioration affected longitudinal visual function in pseudoexfoliation glaucoma (PXG) eyes.

PURPOSE

The aim was to investigate longitudinal changes in the ERM and their association with glaucoma in patients with pseudoexfoliation syndrome (PXS) and to identify factors associated with the changes in ERM and visual field (VF).

PARTICIPANTS

One hundred two eyes with PXG and 32 eyes with nonglaucomatous pseudoexfoliation (ngPX) (mean 8.1±2.6 years of follow-up).

METHODS

Two observers independently assessed the presence and staging of ERM (stages 1, 2, and ≥3) on serial macular images of spectral-domain optical coherence tomography. Clinical characteristics were compared in eyes with ERM (+) and (-) in both groups. The relationship between putative factors and changes in ERM was determined using logistic regression analysis. Prognostic factors of VF worsening were assessed by Cox proportional hazard analysis.

RESULTS

Of the 102 eyes with PXG, 22 (21.6%) had an ERM at baseline; of the latter, 6 eyes deteriorated (all from stage 1 to 2) and 3 eyes with PXG developed new ERM during follow-up. Of the 32 ngPX eyes, 8 (25%) had an ERM at baseline, with none changing over time. The presence of glaucoma was marginally associated with ERM deterioration (odds ratio: 1.061, P =0.064). Incremental change in CMT was the only factor associated with VF progression (hazard ratio: 1.040, P =0.029) in PXG eyes.

CONCLUSIONS

ERM tended to deteriorate more in PXS eyes with than without glaucoma. Incremental change in CMT induced by ERM deterioration affected longitudinal visual function in PXG eyes.

A comprehensive enhanced depth imaging spectral-domain optical coherence tomography analysis of pseudoexfoliation spectrum from non-glaucomatous to advanced stage glaucoma in the aspect of Bruch's membrane opening-minimum rim width

PURPOSE

To compare the correlations between lamina cribrosa (LC) and related structures with Bruch's membrane opening-minimum rim width (BMO-MRW) and retinal nerve fiber layer (RNFL) thickness in pseudoexfoliation syndrome (PXS) and different stages of pseudoexfoliation glaucoma (PXG).

METHODS

This prospective cross-sectional study included 32 PXS eyes of 24 patients and 94 PXG eyes (early-stage (n: 55) and advanced-stage glaucoma (n: 39) of 78 patients. Global and six sectors of RNFL thicknesses and BMO-MRW parameters were measured with enhanced depth imaging (EDI) mode of SD-OCT. Structural parameters; lamina cribrosa thickness (LCT), lamina cribrosa depth (LCD), prelaminar tissue thickness (PLTT), four quadrants of peripapillary choroidal thicknesses (PPCT), and subfoveal choroidal thickness (SFCT) were measured and statistical relationships between the structural parameters have been laid out. We apply the generalized estimating equations method to take into account dependency of right and left eyes.

RESULTS

From PXS to mild and advanced PXG groups LCT and PLTT decrease from 147.29 ± 33.10, 145.62 ± 30.64, 126.30 ± 29.14 and 260.93 ± 185.07, 247.27 ± 142.58, 159.89 ± 86.84, respectively, and LCD varies as 159.89 ± 86.84, 420.88 ± 117.80, and 505.64 ± 183.25. The correlations between LCD, LCT, and PLTT and the stage of the disease are significant. BMO-MRW shows slightly stronger correlations than the RNFL with LC related parameters. SFCT does not exhibit any significant relationship with the stage of the disease. However, PPCT in only the interior quadrant does. The significant correlations between LCD and all quadrants of PPCT is the sign of important anatomic relationship.

CONCLUSION

These findings show that the BMO-MRW parameter may be more sensitive than RNFL and can safely be used in the diagnosis and follow-up in PXS and PXG, but this result should be supported with longer and larger series.

Clinical Analysis of Macular Choroidal Thickness in Pseudoexfoliative Glaucoma and Primary Open-Angle Glaucoma

Purpose

To evaluate the differences in macular choroidal thickness and volume among patients with pseudoexfoliative glaucoma (PXG), patients with primary open-angle glaucoma (POAG), and controls.

Methods

A total of 50 PXG patients (50 eyes) and 56 POAG patients (56 eyes) were selected as the PXG group and the POAG group, respectively, in this case-control study. A total of 54 age-, gender-, IOP-, and axial length-matched healthy individuals (54 eyes) were selected as the control group. Enhanced-depth imaging-optical coherence tomography (EDI-OCT) was used to measure and analyze the choroidal thicknesses and volumes in 9 macular regions of all subjects.

Results

The choroidal thicknesses in the central subfield (CSM), temporal inner macula (TIM), inferior inner macula (IIM), and temporal outer macula (TOM) and the mean macular choroidal thickness were significantly thinner in the PXG group than in the control group (all P < 0.05). The choroidal volumes in the TIM, IIM, and TOM and the mean macular choroidal volume were significantly smaller in the PXG group than in the control group (all P < 0.05). The choroidal thicknesses in the CSM and IIM and the mean macular choroidal thickness were significantly thinner in the PXG group than in the POAG group (all P < 0.05). The choroidal volumes in the IIM and TOM and the mean macular choroidal volume were significantly smaller in the PXG group than in the POAG group (all P < 0.05). Multivariable linear regression analysis showed that the mean macular choroidal thickness was significantly thinner in association with older subjects and longer axial length eyes. There was no association between the macular choroidal thickness of various macular regions and visual field mean defect (MD) in groups PXG and POAG (all P > 0.05).

Conclusions

The macular choroidal thicknesses and volumes (inferior and temporal) in PXG patients were thinner and smaller than those in POAG patients and healthy individuals. The role of choroidal thickness changes in the course of PXG remains unclear. A future prospective study is needed to better define these changes in PXG patients.

Inhibitory and Agonistic Autoantibodies Directed Against the β2-Adrenergic Receptor in Pseudoexfoliation Syndrome and Glaucoma

Pseudoexfoliation syndrome (PEXS) and glaucoma (PEXG) are assumed to be caused by a generalized elastosis leading to the accumulation of PEX material in ocular as well as in extraocular tissues. The exact pathophysiology of PEXS is still elusive. PEXG, the most common type of secondary open-angle glaucoma (OAG), is characterized by large peaks of intraocular pressure (IOP) with a progressive loss of the visual field. Agonistic autoantibodies (agAAbs) against the β₂-adrenergic receptor (AR) have been shown to be present in sera of patients with primary and secondary OAG and ocular hypertension and are seemingly linked to IOP. In the present study, we investigated the autoantibodies directed against the β₂-AR in sera of patients with PEXS and PEXG. We recruited 15, 10, and 15 patients with PEXG, PEXS, and primary OAG, respectively. Ten healthy individuals served as controls. All patients underwent standard ophthalmological examination with Octopus G1 perimetry. agAAbs prepared from serum samples were analyzed in a rat cardiomyocyte-based bioassay for the presence of agAAbs. We identified the interacting loop of the β₂-AR and the immunoglobulin G (IgG) subclasses using synthetic peptides corresponding to the extracellular loops of the receptors and enzyme-linked immunosorbent assay, respectively. None of the controls were β₂-agAAb-positive (0.2 ± 0.5 U). No β₂-agAAbs (0.2 ± 0.4 U), but inhibitory β₂-AAbs were observed in 80% of the patients that partially blocked the drug-induced β₂-adrenergic stimulation; 5.8 ± 1.7 U vs. 11.1 ± 0.9 U for clenbuterol in the absence and the presence of sera from patients with PEXS, respectively. Epitope analyses identified the third extracellular loop of the β₂-AR as the target of the inhibitory β₂-AAbs, being of IgG3 subtype in PEXS patients. In contrast, patients with PEXG showed β₂-agAAbs (5.6 ± 0.9 U), but no inhibitory ones. The β₂-agAAbs levels of patients with PEXG and primary OAG patients (3.9 ± 2.8 U; p > 0.05) were at a similar level. In two cases of PEXG, the β₂-agAAbs exert synergistic effects with clenbuterol. The activity increased from 11.5 ± 0.3 (clenbuterol only) to 16.3 ± 0.9 U. As autoimmune mechanisms were reportedly involved in the pathogenesis of glaucoma, agonistic and inhibitory β₂-AAbs seem to be a part of this multifactorial interplay.

Biomechanics of the optic nerve head and sclera in canine glaucoma: A brief review

Glaucoma is a leading cause of irreversible blindness, a progressive optic neuropathy with retinal ganglion cell (RGC) death beginning in the optic nerve head (ONH). A primary risk factor for developing glaucoma is elevated intraocular pressure (IOP). Reducing IOP is the only treatment proven to be effective at delaying disease progression. Nevertheless, even when patients have their IOP reduced, the majority of them continue to lose vision. There are, in both humans and dogs, significant interindividual variabilities in susceptibilities to IOP-induced optic nerve damage. Vision loss progresses much more slowly in Beagles with open-angle glaucoma (OAG) caused by ADAMTS10 mutation. This can be attributed to the mutation-related altered ocular biomechanical properties. The principal site of optic nerve (ON) damage in glaucoma is the ONH. It is suggested that the biomechanical properties of the ONH and the surrounding peripapillary sclera (PPS) contribute to glaucoma development and progression. As far as the beneficial biomechanical properties of the ONH and PPS for a decreased susceptibility and slow progression of glaucoma, data are inconsistent and conflicting. Recent biomechanical studies on beagles with ADAMTS10 mutation demonstrated that the mutant dogs have mechanically weak posterior sclera. This weakness was associated with a reduced collagen density and a lower proportion of insoluble collagen. These changes, observed before glaucoma development, were considered intrinsic characteristics caused by the mutation rather than a secondary effect of IOP elevation. Further studies of ADAMTS10-OAG may elucidate the effects of altered biomechanical properties of ONH and PPS in determining the glaucoma progression.

Comparison of Macular Choroidal Thickness and Volume between Pseudoexfoliative Glaucoma and Pseudoexfoliative Syndrome

Purpose

To evaluate the difference in macular choroidal thickness and volume between patients with pseudoexfoliative glaucoma (PXG), patients with pseudoexfoliative syndrome (PEX), and normal controls.

Methods

This case-control study included 49 PXG patients (group A), 33 PEX patients (group B), and 42 sex-, age-, and axial length-matched healthy volunteer eyes (group C). The macular choroidal thickness and volume of all subjects studied were measured by enhanced depth imaging optical coherence tomography.

Results

The average macular (AM) choroidal thickness was 170.79 ± 50.18 μm, 184.65 ± 57.54 μm, and 206.46 ± 48.90 μm, and the average volume was 0.52 ± 0.15 μm³, 0.56 ± 0.17 μm³, and 0.63 ± 0.15 μm³ in groups A, B, and C, respectively. The macular choroidal thickness, the volumes of various macular regions, and the average choroidal thickness and volume in group A were lower than those in group C (all P < 0.05). There were no significant differences in the macular choroidal thickness, volumes of various macular regions, or average choroidal thickness or volume between group A and B (all P > 0.05). The macular choroidal thickness and volume of the TIM and SOM in group B were lower than those in group C (P < 0.05). There was no association between the macular choroidal thickness of various macular regions and visual field mean defect (MD) in group A (all P > 0.05).

Conclusion

The macular choroidal thickness in patients with PXG or PEX (TIM and SOM) is thinner than that in normal subjects. The macular choroidal thickness in patients with PXG is not significantly different from that in patients with PEX. The role of macular choroidal thickness changes in the glaucomatous damage of patients with PXG is still unclear.

Analysis of Peripapillary and Macular Choroidal Thickness in Eyes with Pseudoexfoliative Glaucoma and Fellow Eyes

Purpose

To compare differences in peripapillary and macular choroidal thickness in pseudoexfoliative glaucoma (PXG) eyes, nonexfoliative fellow eyes, and normal eyes.

Methods

This case-control study included 37 PXG patients (group A: 37 PXG eyes; group B: 37 nonexfoliative fellow eyes) and 37 sex-, age-, and axial length-matched healthy volunteer eyes (group C). Peripapillary and macular choroidal thickness and volume were measured in all subjects via enhanced-depth imaging-optical coherence tomography.

Results

The average peripapillary (AP) choroidal thickness was (130.10 ± 46.14) μm, (131.43 ± 46.00) μm, and (147.89 ± 53.32) μm; average macular (AM) choroidal thickness was (191.72 ± 68.07) μm, (204.62 ± 69.54) μm, and (215.10 ± 45.40) μm; and average volume was (0.59 ± 0.21) μm³, (0.63 ± 0.21) μm³, and (0.65 ± 0.14) μm³ in groups A, B, and C, respectively. NIP choroidal thickness was significantly lower in groups A and B than in group C (P < 0.05). TIM and TOM choroidal thickness and volume were significantly lower in group A than in group C (P < 0.05). NIM, SIM, NOM, IOM, AM choroidal thickness and volume, and CSM choroidal thickness were significantly lower in group A than in group B (P < 0.05). CSM, TIM, and TOM in group A and TIM, TOM choroidal thickness, and volume in group B were significantly lower than in group C (P < 0.05).

Conclusions

NIP choroidal thickness in PXG eyes and nonexfoliative fellow eyes and temporal macular choroidal thickness in PXG eyes were significantly lower than in normal eyes. Macular choroidal thickness (except in temporal regions) was significantly lower in PXG eyes than in nonexfoliative fellow eyes. Changes in peripapillary and macula choroidal thickness further elucidate the choroid's role in PXG development and progression.

Clinical Features of Pseudoexfoliative Glaucoma in Treated Polish Patients

PURPOSE

The aim of this study was to describe clinical characteristics of glaucomatous optic neuropathy in treated Polish patients with pseudoexfoliative glaucoma.

METHODS

In the course of the study, 348 eyes of 231 patients with pseudoexfoliative glaucoma. The patients involved in the study were treated in the Department of Diagnostic and Microsurgery of Glaucoma in Lublin between 2012 and 2019. The following parameters were assessed in the examination: visual acuity, slit-lamp biomicroscopy with evaluation of anterior segment of the eye, gonioscopic examination, stereoscopic fundus examination of the eye, intraocular pressure, visual field, and pachymetry.

RESULTS

The mean age of all the patients was 73.16 years (SD±8.03). The mean age of women was 74.06 (SD±6.97), and the mean age of men was 71.8 (SD±8.51, p=0.006265). Women represented 37.93% (n=132) of the studied group, while men 62.07% (n=216). In the group of patients younger than 65 years of age, 27.9% were male and 15% female (p=0.0021). In the whole studied group, mean peak IOP was 29.25 mmHg with higher mean values in male patients (M vs F: 33.24 mmHg vs 26.86 mmHg; p=0.000). Peak values exceeding 30 mmHg were significantly more frequent in males (M vs F: 56.5% vs 31.9%; p=0.0000). Peak IOP never exceeding 21 mmHg was observed in 18.6% of the patients. The mean value of MD (Mean Deviation) was -12.85 dB in the whole group. The men were more likely to have more advanced glaucoma, according to MD (M vs F: -16.35 dB vs -11.13 dB; p=0.0000).

CONCLUSION

Pseudoexfoliative glaucoma was more frequently observed in men with younger age, higher IOP, and more advanced glaucoma. Normotensive glaucoma was observed in 18.6% of the patients with pseudoexfoliative glaucoma.

Optical coherence tomography angiography of the peripapillary region and macula in normal, primary open angle glaucoma, pseudoexfoliation glaucoma and ocular hypertension eyes

AIM

To evaluate and compare the peripapillary and retinal vasculature changes in primary open angle glaucoma (POAG), pseudoexfoliation glaucoma (PXG), ocular hypertension (OHT) and normal eyes using optical coherence tomography angiography (OCTA).

METHODS

A total of 114 POAG, PXG and OHT eyes of 60 patients and 46 eyes of 23 healthy control participants with good quality OCTA images were included. The PXG, POAG, OHT, and control groups (aged 68.17±6.30y, 61.11±10.26y, 58.1±8.9y, and 56.9±4.6y, respectively) contained of 46, 36, 32, and 46 eyes, respectively. Measurements of vessel density (VD) in the peripapillary region and macula, average retinal inner thickness, and retinal nerve fiber layer thickness (RNFLT) were compared among groups. In order to test the accuracy of differentiation between eyes with and without glaucoma, the area was calculated under the receiver operating characteristic (ROC) curves.

RESULTS

The VD in glaucomatous eyes was significantly lower than the control group in all peripapillary sectors (44.35%±6.78% vs 50.47%±1.83%, P<0.001), the superficial (44.08%±5.46% vs 51.28%±2.85%, P<0.001) and the deep (45.13%±8.55% vs 54.20%±5.44%, P<0.001) vascular plexus. There was a significant difference in peripapillary VD between glaucomatous and OHT eyes (44.35%±6.78% vs 49.86%±2.45%, P<0.001). The OHT group featured a lower superficial (48.06%±4.32% vs 51.28%±2.85%, P=0.027) and deep plexus (48.70%±5.99% vs 54.20%±5.44%, P=0.013) whole image vessel density (wiVD) than did the control group. The average macular superficial plexus wiVD was significantly lower in eyes with PXG than in eyes with POAG (42.22%±5.36% vs 46.54%±5.56%, P=0.046).

CONCLUSION

OCTA can measure reduced peripapillary and macular VD in eyes with glaucoma and OHT, and these results are correlated to functional and structural glaucomatous alterations. Peripapillary and macular superficial plexus VD is lower in eyes with PXG than in eyes with POAG. Furthermore, the OHT eyes demonstrate impaired macular vasculature in both superficial and deep plexus.

No Relationship between Visual Field Damage and Choroidal Thickness in Eyes with Primary Open-Angle Glaucoma

PURPOSE

To evaluate the association between visual field damage and choroidal thickness (ChT) in subjects with primary open-angle glaucoma.

METHODS

In this cross-sectional study, 115 eyes of 58 glaucoma patients and 112 eyes of 56 healthy subjects were enrolled. ChT at the fovea, 0.5 mm temporal, 1.5 mm temporal, 0.5 mm nasal, 1.5 mm nasal to the fovea, and all quadrants in the peripapillary region were analyzed. The subjects with glaucoma were further classified by Hodapp-Anderson-Parrish scores.

RESULTS

There was no difference between glaucoma and healthy subjects in mean age, gender, and refractive errors. The overall average thickness of the retinal nerve fiber layer (RNFL) was significantly lower in the eyes with glaucoma compared to the normal subjects (p < 0.01) and decreased in proportion to the severity of glaucoma (normal, 99.4; no defect, 89; early, 80.4; moderate, 63.1; and severe, 51 µm). ChT measured from the foveal region, at a distance of 500 μm from the fovea (nasal and temporal), and 1,500 μm from the fovea (nasal and temporal) did not significantly vary between the two groups. As well, peripapillary ChT did not significantly differ in proportion to the severity of glaucoma (p > 0.05 for all quadrants). The RNFL and ChT measurements were not significantly correlated with any peripapillary location (|r| ≤ 0.17, p > 0.05). The visual field mean deviation/pattern standard deviation and ChT measurements were also not significantly correlated with any peripapillary and macular location (|r| ≤ 0.12, p > 0.05).

CONCLUSIONS

There was no significant difference in macular and peripapillary ChT between healthy and glaucomatous eyes that differed in severity of visual field damage. This suggests that the structural features of the choroid may not be associated with severity of primary open-angle glaucoma.

Comparison of macular choroidal thickness in patients with pseudoexfoliation syndrome to normal control subjects with enhanced depth SD-OCT imaging

Purpose

To test the hypothesis that macular choroidal thickness is lower in patients with pseudoexfoliation syndrome (PXS) as compared to healthy control subjects.

Methods

In this cross-sectional, observational study, 38 non-glaucomatous PXS subjects and 37 healthy volunteers were enrolled in a tertiary care Glaucoma Clinic. The macular region was scanned with the enhanced depth imaging (EDI) protocol of a spectral domain optical coherence tomography (SD-OCT) device (Spectralis OCT, Heidelberg Engineering, Heidelberg, Germany). Macular choroidal thickness and volumes were compared in nine sectors of the Early Treatment Diabetic Retinopathy Study (ETDRS) layout profile across the central 3.45 mm zone after manual segmentation of the choroidal thickness. Linear mixed modeling was used to adjust for confounding variables.

Results

Six PXS eyes and 8 control eyes were excluded due to poor image quality leaving 32 PXS and 29 control eyes for final analyses. The average age and axial length of the PXS and control groups were 67.94 ± 7.30 vs 64.86 ± 7.04 and 22.91 ± 0.77 vs 23.24 ± 0.66 mm, respectively, (P = 0.10 and 0.20). There was no significant difference in retinal nerve fiber layer (RNFL) thickness between the two groups (P = 0.24). The choroidal thickness was significantly lower in the central subfield subfoveal area (P = 0.02) and in the inner superior (P = 0.03) and inner nasal quadrants (P = 0.03) in the PXS group compared to the control group, as was the choroidal volume (P = 0.02). No significant difference was found in macular choroidal thickness after adjusting for age, gender, and axial length. While there was a significant negative association between age and central subfield choroidal thickness in the control group (r = -0.48, P = 0.01), this association was not significant in the PXS group (r = -0.08, P = 0.68).

Conclusions

Our findings demonstrate that the choroid does not seem to be significantly altered in PXS eyes. Choroidal thickness changes need to be explored in PXS eyes with glaucoma.

Evaluation of the Macular Choroidal Thickness Using Spectral Optical Coherence Tomography in Pseudoexfoliation Glaucoma

PURPOSE

To evaluate the choroidal thickness (CT) in pseudoexfoliative (PEX) glaucoma and age-matched healthy subjects using spectral optical coherence tomography (SD-OCT).

PATIENTS AND METHODS

In this prospective study, 32 eyes of 32 PEX glaucoma patients and 30 eyes of 30 age-matched healthy subjects were enrolled. The CT is measured perpendicularly (from the outer edge of the hyperreflective retinal pigment epithelium to the inner sclera) at the fovea, and 1.5 mm temporal, 3.0 mm temporal, 1.5 mm nasal, and 3.0 mm nasal to the fovea using SD-OCT (RTVue-100).

RESULTS

The groups were similar regarding the mean age and axial length values (both, P>0.05). The CT measurements were 182.12 ± 39.88 and 201.56 ± 32.00 μm at 1.5 mm nasal to the fovea (P=0.039), and 126.47 ± 32.12 and 146.60 ± 31.37 μm at 3.0 mm nasal to the fovea (P=0.015) in the PEX glaucoma and control groups, respectively. There were no significant differences in the subfoveal and temporal CT measurements among the 2 groups (all, P>0.05).

CONCLUSIONS

The findings of this study indicate that PEX glaucoma causes significant thinning in the nasal choroid. Thus, measuring the CT with SD-OCT may be the way of better clarification of the relationship between PEX and glaucomatous optic neuropathy.

Prevalence of Pseudoexfoliation Syndrome and Associated Factors in South Koreans: The Korean National Health and Nutrition Examination Survey

PURPOSE

To investigate the prevalence of pseudoexfoliation syndrome (PXS) and factors associated with PXS in South Koreans by analyzing data from the Korean National Health and Nutrition Examination Survey (KNHANES).

METHODS

Using the KNHANES database of 2009-2012, 13,223 participants aged 50 years or older were included. Participants underwent standardized interviews and systemic and ocular examinations. Systemic factors analyzed included age, sex, daily length of sun exposure, presence of Raynaud phenomenon or migraine, hypertension, diabetes mellitus, body mass index, serum lipid profile, duration and frequency of smoking, and alcohol consumption. Evaluated ocular factors were refractive error, presence of cataract and glaucoma, intraocular pressure, and peripheral anterior chamber depth. Logistic regression analysis was performed to identify factors associated with the presence of PXS.

RESULTS

PXS was found in 16 participants (0.12%). When compared with the non-PXS group, eyes with PXS showed a higher prevalence of cataract (p = 0.020). In logistic regression analysis, age (odds ratio, OR, 1.04, 95% confidence interval, CI, 0.99-1.09; p = 0.016) and the presence of cataract (OR 8.17, 95% CI 1.06-62.84; p = 0.044) were associated with the presence of PXS. Sun exposure for ≥5 hours/day was marginally associated with the presence of PXS (OR 2.76, 95% CI 0.96-7.95; p = 0.060).

CONCLUSION

The prevalence of PXS per 1000 persons was 1.10 in South Koreans aged ≥50 years. Participants with PXS had a higher prevalence of cataract, were older, and were more likely to be exposed to the sun for ≥5 hours/day than participants without PXS.

Pseudoexfoliation syndrome: Effect of phacoemulsification on intraocular pressure and its diurnal variation

Purpose

To evaluate the effect of phacoemulsification on intraocular pressure (IOP) in pseudoexfoliation (PEX) syndrome and its diurnal variation.

Methods

In this prospective, non-comparative, interventional case series, phacoemulsification was done for patients with PEX and concomitant visually significant cataract. Follow-up examinations including IOP measurement were done at postoperative day 1, week 1, month 1, month 3, and month 6. All IOP measurements were performed twice daily: once in the morning between 8 and 10 AM and the other in the evening between 6 and 8 PM. The minimum and maximum IOP and the mean IOP were recorded. IOP variation was defined as the difference between maximum and minimum pressures.

Results

Sixty-eight eyes of 68 patients were analyzed. The mean IOP dropped from 17.45 ± 3.32 mm Hg to 12.57 ± 1.58 mm Hg at 6 months. The minimum and maximum IOP dropped from 14.97 ± 3.46 mm Hg and 20.03 ± 3.39 to 11.53 ± 1.79 mm Hg and 13.01 ± 1.81 after 6 months, respectively. Diurnal IOP variation dropped from 5.06 ± 1.85 mm Hg (range 2–10) at baseline to 1.49 ± 0.93 mm Hg (range 0–4) at postoperative month 6 (p < 0.001 for all). This drop was not correlated with age and CCT, but was strongly correlated with baseline IOP variation (r = 0.847, p < 0.001).

Conclusion

Phacoemulsification without any additional intervention can be an attractive choice in managing the IOP and its diurnal variations in pseudoexfoliation patients, even with elevated IOP, who do not have advanced optic nerve damage.

A porohyperelastic finite element model of the eye: the influence of stiffness and permeability on intraocular pressure and optic nerve head biomechanics

Progressively deteriorating visual field is a characteristic feature of primary open-angle glaucoma (POAG), and the biomechanics of optic nerve head (ONH) is believed to be important in its onset. We used porohyperelasticity to model the complex porous behavior of ocular tissues to better understand the effect variations in ocular material properties can have on ONH biomechanics. An axisymmetric model of the human eye was constructed to parametrically study how changes in the permeabilities of retina-Bruch's-choroid complex (k(RBC)), sclera k(sclera), uveoscleral pathway (k(UVSC)) and trabecular meshwork k(TM) as well as how changes in the stiffness of the lamina cribrosa (LC) and sclera affect IOP, LC strains, and translaminar interstitial pressure gradients (TLIPG). Decreasing k(RBC) from 5 × 10(- 12) to 5 × 10(- 13) m/s increased IOP and LC strains by 17%, and TLIPG by 21%. LC strains increased by 13% and 9% when the scleral and LC moduli were decreased by 48% and 50%, respectively. In addition to the trabecular meshwork and uveoscleral pathway, the retina-Bruch's-choroid complex had an important effect on IOP, LC strains, and TLIPG. Changes in k(RBC) and scleral modulus resulted in nonlinear changes in the IOP, and LC strains especially at the lowest k(TM) and k(UVSC). This study demonstrates that porohyperelastic modeling provides a novel method for computationally studying the biomechanical environment of the ONH. Porohyperelastic simulations of ocular tissues may help provide further insight into the complex biomechanical environment of posterior ocular tissues in POAG.

[New pathogenetic insights into pseudoexfoliation syndrome/glaucoma. Therapeutically relevant?]

Pseudoexfoliation (PEX) syndrome is a genetically determined, generalized disease of the extracellular matrix leading to the progressive deposition of an abnormal fibrillar material in various intraocular and extraocular tissues including the trabecular meshwork. It thus represents the most common identifiable cause of open-angle glaucoma and a leading cause of blindness worldwide. The PEX-specific fibrotic matrix process, a stress-induced elastosis, is characterized by an excessive production and abnormal cross-linking of elastic microfibrils into fibrillar PEX aggregates. Co-modulating factors triggering this fibrotic process include elevated concentrations of fibrogenic growth factors, such as TGF-β1, reduced activity of proteolytic enzymes, subtle inflammatory processes and various external stress factors, such as oxidative stress. Genetic studies identified a highly significant association between several polymorphisms in the LOXL1 (lysyl oxidase-like 1) gene with both PEX syndrome and PEX glaucoma. As these LOXL1 risk variants were found to occur in almost 100% of PEX patients throughout all geographical populations worldwide, LOXL1 appears to represent a principal risk factor for manifestation of the PEX phenotype. LOXL1 is a pivotal cross-linking enzyme in extracellular matrix metabolism and seems to be specifically required for elastic fiber formation and stabilization. The available data suggest that LOXL1 enzyme function and expression are dysregulated in PEX tissues and thereby play a central role in glaucoma development. On the one hand, increased expression of LOXL1 and elastic fiber components contributes to the formation of abnormally cross-linked PEX aggregates in the outflow pathways leading to increased outflow resistance and intraocular pressure. On the other hand, reduced expression and inadequate tissue levels of LOXL1 may lead to degenerative tissue alterations, particularly in the lamina cribrosa adversely affecting the biomechanical properties of this critical tissue. This PEX-specific elastinopathy of the lamina cribrosa rendering PEX eyes more vulnerable to pressure-induced optic nerve damage may constitute an independent risk factor for glaucoma development. The findings may have direct consequences for the clinical management of PEX patients underlining the need for an exact diagnosis, a strict IOP-reducing therapy and a close and regular follow-up.

LOXL1 deficiency in the lamina cribrosa as candidate susceptibility factor for a pseudoexfoliation-specific risk of glaucoma

PURPOSE

To test the hypothesis that a primary disturbance in lysyl oxidase-like 1 (LOXL1) and elastin metabolism in the lamina cribrosa of eyes with pseudoexfoliation syndrome constitutes an independent risk factor for glaucoma development and progression.

DESIGN

Observational, consecutive case series.

PARTICIPANTS

Posterior segment tissues obtained from 37 donors with early and late stages of pseudoexfoliation syndrome without glaucoma, 37 normal age-matched control subjects, 5 eyes with pseudoexfoliation-associated open-angle glaucoma, and 5 eyes with primary open-angle glaucoma (POAG).

METHODS

Protein and mRNA expression of major elastic fiber components (elastin, fibrillin-1, fibulin-4), collagens (types I, III, and IV), and lysyl oxidase crosslinking enzymes (LOX, LOXL1, LOXL2) were assessed in situ by quantitative real-time polymerase chain reaction, (immuno)histochemistry, and light and electron microscopy. Lysyl oxidase-dependent elastin fiber assembly was assessed by primary optic nerve head astrocytes in vitro.

MAIN OUTCOME MEASURES

Expression levels of elastic proteins, collagens, and lysyl oxidases in the lamina cribrosa.

RESULTS

Lysyl oxidase-like 1 proved to be the major lysyl oxidase isoform in the normal lamina cribrosa in association with a complex elastic fiber network. Compared with normal and POAG specimens, lamina cribrosa tissues obtained from early and late stages of pseudoexfoliation syndrome without and with glaucoma consistently revealed a significant coordinated downregulation of LOXL1 and elastic fiber constituents on mRNA and protein level. In contrast, expression levels of collagens and other lysyl oxidase isoforms were not affected. Dysregulated expression of LOXL1 and elastic proteins was associated with pronounced (ultra)structural alterations of the elastic fiber network in the laminar beams of pseudoexfoliation syndrome eyes. Inhibition of LOXL1 interfered with elastic fiber assembly by optic nerve head astrocytes in vitro.

CONCLUSIONS

The findings provide evidence for a pseudoexfoliation-specific elastinopathy of the lamina cribrosa resulting from a primary disturbance in LOXL1 regulation and elastic fiber homeostasis, possibly rendering pseudoexfoliation syndrome eyes more vulnerable to pressure-induced optic nerve damage and glaucoma development and progression.