Comparing glaucomatous optic neuropathy in primary open angle and primary angle closure glaucoma eyes by scanning laser polarimetry-variable corneal compensation

Comparison of Vascular Density and Structural Patterns Between POAG and PACG

PURPOSE

To compare the pattern of vascular density and structural damage in primary open angle glaucoma (POAG) with primary angle-closure glaucoma (PACG) using OCT and OCT angiography (OCTA) in the optic nerve head, circumpapillary, and macular regions.

METHODS

One hundred and thirty-one eyes of 82 patients (53 eyes with PACG and 78 eyes with POAG) were enrolled into this study. Patients underwent complete ophthalmic examination, Bruch's membrane opening minimum rim width (BMO-MRW), circumpapillay retinal nerve fiber layer (cpRNFL), and macular ganglion cell complex (GCC) measurements and vascular density determination of the peripapillary and macular area with OCT and OCTA. Linear mixed model was used for statistical analysis.

RESULTS

There was no significant difference between the two groups in terms of age(P=0.94) and visual field mean deviation (P=0.78). Female-to-male ratio was higher in PACG patients than POAG group(P=0.02), and AL was shorter in PACG eyes(P<0.001). cpRNFL and GCC were not different between the 2 groups (all P values >0.05, except for nasal segment cpRNFL). Vessel densities in the peripapillary and macular areas were comparable between the 2 groups (all P values>0.05). Although BMO-MRW was thicker in PACG eyes on univariate analysis, multivariable analysis showed no significant difference between the 2 groups(P>0.05).

CONCLUSIONS

PACG and POAG eyes with similar visual field damages have comparable structural damage patterns in the peripapillary and inner macular thickness and vessel density measurements.

Comparison of medical comorbidity between patients with primary angle-closure glaucoma and a control cohort: a population-based study from Taiwan

OBJECTIVE

To determine the prevalence and risk of systemic comorbidities in primary angle-closure glaucoma in Taiwan population.

METHODS

We included 3322 primary angle-closure glaucoma (PACG) subjects and randomly selected patients without PACG from the Taiwan National Health Insurance Research Database and frequency matched four of them (n=13 288) to each PACG patient, based on age and sex. The univariable and multivariable unconditional logistic regression models were used to estimate the effect of comorbidities on the risk of PACG as indicated by the OR with 95% CI.

RESULTS

The mean age of the PACG group was 65.2±12.7 years, and 61.1% of the patients were female. The risk of PACG was greater for patients with the comorbidities of hyperlipidaemia (ORs: 1.11), headaches (ORs: 1.13), liver diseases (ORs: 1.14), peptic ulcers (ORs: 1.10) and cataract (ORs: 3.80). For the male group, diabetes (ORs: 1.19), liver diseases (ORs: 1.29) and cataract (ORs: 4.30) were significantly associated with increasing PACG risk. For the female group, hyperlipidaemia (ORs: 1.13), headaches (ORs: 1.15), peptic ulcers (ORs: 1.14) and cataract (ORs: 3.54) were significantly associated with increasing PACG risk. For the age group of 64 years and younger, patients with comorbidity of hyperlipidaemia (ORs: 1.20), peptic ulcers (ORs: 1.21) and cataract (ORs: 5.91) were significantly associated with increasing PACG risk. For the age group of 65 years and older, patients with cataract were significantly associated with increasing PACG risk (ORs: 5.07).

CONCLUSIONS

Clinicians should be aware of slightly increased PACG risk in the subjects with the medical comorbidities of hyperlipidaemia, headaches, liver diseases and peptic ulcers. However, cataract is the strongest risk factor of PACG.

All roads lead to glaucoma: Induced retinal injury cascades contribute to a common neurodegenerative outcome

Glaucoma describes a distinct optic neuropathy with complex etiology and a variety of associated risk factors, but with similar pathological endpoints. Risk factors such as age, increased intraocular pressure (IOP), low mean arterial pressure, and autoimmune disease, can all be associated with death of retinal ganglion cells (RGCs) and optic nerve head remodeling. Today, IOP management remains the standard of care, even though IOP elevation is not pathognomonic of glaucoma, and patients can continue to lose vision despite effective IOP control. A contemporary view of glaucoma as a complex, neurodegenerative disease has developed, along with the recognition of a need for new disease modifying retinal treatment strategies and improved outcomes. However, the distinction between risk factors triggering the disease process and retinal injury responses is not always clear. In this review, we attempt to distinguish between the various triggers, and their association with subsequent key RGC injury mechanisms. We propose that distinct glaucomatous risk factors result in similar retinal and optic nerve injury cascades, including oxidative and metabolic stress, glial reactivity, and altered inflammatory responses, which induce common molecular signals to induce RGC apoptosis. This organization forms a coherent disease framework and presents conserved targets for therapeutic intervention that are not limited to specific risk factors.

Optic nerve head and fibre layer imaging for diagnosing glaucoma

BACKGROUND

The diagnosis of glaucoma is traditionally based on the finding of optic nerve head (ONH) damage assessed subjectively by ophthalmoscopy or photography or by corresponding damage to the visual field assessed by automated perimetry, or both. Diagnostic assessments are usually required when ophthalmologists or primary eye care professionals find elevated intraocular pressure (IOP) or a suspect appearance of the ONH. Imaging tests such as confocal scanning laser ophthalmoscopy (HRT), optical coherence tomography (OCT) and scanning laser polarimetry (SLP, as used by the GDx instrument), provide an objective measure of the structural changes of retinal nerve fibre layer (RNFL) thickness and ONH parameters occurring in glaucoma.

OBJECTIVES

To determine the diagnostic accuracy of HRT, OCT and GDx for diagnosing manifest glaucoma by detecting ONH and RNFL damage.

SEARCH METHODS

We searched several databases for this review. The most recent searches were on 19 February 2015.

SELECTION CRITERIA

We included prospective and retrospective cohort studies and case-control studies that evaluated the accuracy of OCT, HRT or the GDx for diagnosing glaucoma. We excluded population-based screening studies, since we planned to consider studies on self-referred people or participants in whom a risk factor for glaucoma had already been identified in primary care, such as elevated IOP or a family history of glaucoma. We only considered recent commercial versions of the tests: spectral domain OCT, HRT III and GDx VCC or ECC.

DATA COLLECTION AND ANALYSIS

We adopted standard Cochrane methods. We fitted a hierarchical summary ROC (HSROC) model using the METADAS macro in SAS software. After studies were selected, we decided to use 2 x 2 data at 0.95 specificity or closer in meta-analyses, since this was the most commonly-reported level.

MAIN RESULTS

We included 106 studies in this review, which analysed 16,260 eyes (8353 cases, 7907 controls) in total. Forty studies (5574 participants) assessed GDx, 18 studies (3550 participants) HRT, and 63 (9390 participants) OCT, with 12 of these studies comparing two or three tests. Regarding study quality, a case-control design in 103 studies raised concerns as it can overestimate accuracy and reduce the applicability of the results to daily practice. Twenty-four studies were sponsored by the manufacturer, and in 15 the potential conflict of interest was unclear.Comparisons made within each test were more reliable than those between tests, as they were mostly based on direct comparisons within each study.The Nerve Fibre Indicator yielded the highest accuracy (estimate, 95% confidence interval (CI)) among GDx parameters (sensitivity: 0.67, 0.55 to 0.77; specificity: 0.94, 0.92 to 0.95). For HRT measures, the Vertical Cup/Disc (C/D) ratio (sensitivity: 0.72, 0.60 to 0.68; specificity: 0.94, 0.92 to 0.95) was no different from other parameters. With OCT, the accuracy of average RNFL retinal thickness was similar to the inferior sector (0.72, 0.65 to 0.77; specificity: 0.93, 0.92 to 0.95) and, in different studies, to the vertical C/D ratio.Comparing the parameters with the highest diagnostic odds ratio (DOR) for each device in a single HSROC model, the performance of GDx, HRT and OCT was remarkably similar. At a sensitivity of 0.70 and a high specificity close to 0.95 as in most of these studies, in 1000 people referred by primary eye care, of whom 200 have manifest glaucoma, such as in those who have already undergone some functional or anatomic testing by optometrists, the best measures of GDx, HRT and OCT would miss about 60 cases out of the 200 patients with glaucoma, and would incorrectly refer 50 out of 800 patients without glaucoma. If prevalence were 5%, e.g. such as in people referred only because of family history of glaucoma, the corresponding figures would be 15 patients missed out of 50 with manifest glaucoma, avoiding referral of about 890 out of 950 non-glaucomatous people.Heterogeneity investigations found that sensitivity estimate was higher for studies with more severe glaucoma, expressed as worse average mean deviation (MD): 0.79 (0.74 to 0.83) for MD < -6 db versus 0.64 (0.60 to 0.69) for MD ≥ -6 db, at a similar summary specificity (0.93, 95% CI 0.92 to 0.94 and, respectively, 0.94; 95% CI 0.93 to 0.95; P < 0.0001 for the difference in relative DOR).

AUTHORS' CONCLUSIONS

The accuracy of imaging tests for detecting manifest glaucoma was variable across studies, but overall similar for different devices. Accuracy may have been overestimated due to the case-control design, which is a serious limitation of the current evidence base.We recommend that further diagnostic accuracy studies are carried out on patients selected consecutively at a defined step of the clinical pathway, providing a description of risk factors leading to referral and bearing in mind the consequences of false positives and false negatives in the setting in which the diagnostic question is made. Future research should report accuracy for each threshold of these continuous measures, or publish raw data.

Long-Term Use of Selective Serotonin Reuptake Inhibitors and Risk of Glaucoma in Depression Patients

This study investigated whether the long-term use of selective serotonin reuptake inhibitors (SSRIs) influences the risk of primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG) in the Chinese ethnic population in Taiwan.The authors retrieved the data under analysis from the National Health Insurance Research Database in Taiwan and identified 26,186 newly diagnosed depression patients without preexisting glaucoma. The study cohort included 13,093 patients with over 1 year of SSRI use, and a comparison cohort of 13,093 patients who had never used SSRIs. The main outcome was a diagnosis of POAG or PACG during follow-up. The authors used univariable and multivariable Cox proportional hazards regression models to assess the effects of SSRIs on the risk of POAG and PACG.The cumulative incidences of POAG and PACG between the SSRI and comparison cohorts exhibited nonsignificant differences (log-rank test P = .52 for POAG, P = .32 for PACG). The overall incidence of POAG in the SSRI cohort was nonsignificantly higher than that in the comparison cohort (1.51 versus 1.39 per 1000 person-years), with an adjusted hazard ratio of 1.07 (95% confidence interval = 0.82-1.40). The overall incidence of PACG in the SSRI cohort was nonsignificantly lower than that in the comparison cohort (0.95 versus 1.11 per 1000 person-years), with an adjusted hazard ratio of 0.85 (95% confidence interval = 0.62-1.18).The long-term use of SSRIs does not influence the risk of POAG or PACG in depression patients.

Association between p53 codon 72 (Arg72Pro) polymorphism and primary open-angle glaucoma in Iranian patients

BACKGROUND

Glaucomatous neuropathy is a type of cell death due to apoptosis. The p53 gene is one of the regulatory genes of apoptosis. Recently, the association between the p53 gene encoding for proline at codon 72 and primary open-angle glaucoma (POAG) has been studied in some ethnic groups. This study is the first association analysis of POAG and p53 codon 72 polymorphism in Iranian patients.

METHODS

A cohort of 65 unrelated patients with POAG (age range from 12-62 years, mean ± SD of 40.16 ± 17.51 years) and 65 unrelated control subjects (without glaucoma, age range of 14-63 years, mean ± SD of 35.64 ± 13.61 years) were selected. In Iranian POAG patients and normal healthy controls, the p53 codon 72 polymorphism in exon 4 was amplified using polymerase chain reaction. The amplified DNA fragments were digested with the BstUI restriction enzyme, and the digestion patterns were used to identify the alleles for the polymorphic site.

RESULTS

Comparisons revealed significant differences in allele and genotype frequencies of Pro72Arg between POAG patients and control group. A higher risk of POAG was associated with allele Pro (OR = 2.1, 95% CI = 1.2-3.4) and genotype Pro/Pro (OR = 3.9, 95% CI = 0.13-12.7).

CONCLUSION

The p53 Pro72 allele was more frequent in Iranian POAG patients than in the control group (P<0.05). The present findings show that the individuals with the Pro/Pro genotype may be more likely to develop POAG. However, additional studies are necessary to confirm this association.

Association between plasma endothelin-1 and severity of different types of glaucoma

PURPOSE

Endothelin-1 (ET-1) has been suggested to play an important role in the pathogenesis of glaucoma. Herein, we studied whether increased levels of plasma ET-1 are associated with changes in the visual field and changes in optical coherence tomography (OCT)-measured retinal nerve fiber layer (RNFL) thickness in patients with different types of glaucoma.

PATIENTS AND METHODS

: Plasma concentration of ET-1 was determined in 31 patients with primary open-angle glaucoma, 18 patients with normal tension glaucoma, 16 patients with primary angle-closure glaucoma, and in 37 normal controls. In all participants, visual field testing was performed and OCT was used to measure RNFL thickness. The correlation between mean ET-1 level and changes in the visual field (mean deviation, dB) and changes in OCT-measured RNFL thickness in 1 randomly selected eye from each patient in each group was then evaluated.

RESULTS

The ET-1 level was 3.27±1.25 pg/mL in the primary open-angle glaucoma group (-14.09±8.76 dB), 3.12±1.46 pg/mL in the normal tension glaucoma group (-8.87±6.15 dB), 2.58±.22pg/mL in the primary angle-closure glaucoma group (-14.55±10.2 dB), and 1.53±1.49 pg/mL in the control group. Although mean ET-1 levels were significantly higher in all 3 of the glaucoma groups than in the control group, there was no significant difference in ET-1 level among the 3 glaucoma groups. In addition, no significant correlation was found between levels of plasma ET-1 and structural or functional changes in patients with different types of glaucoma.

CONCLUSIONS

: There was no correlation between plasma levels of ET-1 and severity of glaucoma. The role ET-1 plays in the pathogenesis of glaucoma remains to be determined.

Retinal nerve fiber layer defect patterns in primary angle-closure and open-angle glaucoma: a comparison using optical coherence tomography

PURPOSE

To compare the patterns of retinal nerve fiber layer (RNFL) thickness loss in primary angle-closure glaucoma (PACG) and primary open-angle glaucoma (POAG) using optical coherence tomography (OCT).

METHODS

Forty-three participants with PACG and 60 with POAG underwent fast RNFL thickness measurement by OCT. Eyes were classified according to the visual field mean deviation (VF-MD) into mild (>-8 dB), moderate (-8 dB to >-16 dB), and advanced (≤ -16 dB) glaucoma subgroups. The raw RNFL thickness data were compared with data from the Thai normative database.

RESULTS

Mean (SD) age was 67.0 (9.6) and 64.1 (11.6) years in the PACG and POAG groups, respectively (P = 0.19). In the mild subgroups, a focal RNFL thickness loss was found in the inferior area in the POAG group, but not in the PACG group. The RNFL defect involved sectors 1, 6, and 7 in the moderately advanced disease subgroups of both PACG and POAG and extended through almost all sectors in the advanced disease subgroups. The deepest RNFL defect, -17.25 μm, was found in sector 6 of the mild POAG subgroup, compared with -8.78 μm in the PACG group (P = 0.04). The number of affected points in each sector in the mild subgroups was greater in the POAG group than in the PACG group.

CONCLUSION

Participants with mild POAG had deeper and more localized RNFL defects than did participants with PACG. The pattern was similar in participants with moderate or advanced disease.