Primary Open-angle Glaucoma Subjects Research Articles

Visual Field and Optical Coherence Tomography Parameters With and Without Positive Family History of Glaucoma.

To evaluate the Retinal Nerve Fiber Layer and Ganglion Cell Complex thickness using Spectral Domain Optical Coherence Tomography with and without positive family history of Primary Open Angle Glaucoma and its relation to visual field. Total 120 eyes with each subjects with positive family history of Primary Open Angle Glaucoma (Group I, n=30) and healthy subjects without positive family history of Primary Open Angle Glaucoma (Group II, n=30) undergone complete ophthalmic evaluation with Retinal Nerve Fiber Layer, Ganglion Cell Complex and VF obtained from Spectral Domain Optical Coherence Tomography RTVue-100 and Humphrey visual field respectively .The measurements were analyzed and compared among two groups using independent-t test by using SPSS version 23.The relationship of Retinal Nerve Fiber Layer with visual field were evaluated with correlation analysis. There were 75 patients included in the study.nasal, temporal RNFL and average Ganglion Cell Complex was significantly lower and thinner in Group I with mean difference of -8.53±2.30 µm (p<0.001), -7.35±3.34 µm (p<0.001), -8.52±3.58µm (p<0.001),-11.87±2.24µm (p<0.001), -5.31±1.95µm (p<0.001) and -8.05±1.52µm (p<0.001) respectively. Correlation plot with Retinal Nerve Fiber Layer thickness as predictor of Mean Deviation and Pattern Standard Deviation indicated statistically significant degree of determination in Group I (r=0.455 and r=0.623, p<0.001 and p<0.001). The Optical Coherence Tomography and visual field Parameters are lower in group I and used as an early predictor, diagnosis, monitoring and management.

Aqueous humor TGFβ and fibrillin-1 in Tsk mice reveal clues to POAG pathogenesis

Aqueous humor (AH) and blood levels of transforming growth factor β (TGFβ) are elevated in idiopathic primary open angle glaucoma (POAG) representing a disease biomarker of unclear status and function. Tsk mice display a POAG phenotype and harbor a mutation of fibrillin-1, an important regulator of TGFβ bioavailability. AH TGFβ2 was higher in Tsk than wild-type (WT) mice (by 34%; p = 0.002; ELISA); similarly, AH TGFβ2 was higher in human POAG than controls (2.7-fold; p = 0.00005). As in POAG, TGFβ1 was elevated in Tsk serum (p = 0.01). Fibrillin-1 was detected in AH from POAG subjects and Tsk mice where both had similar levels relative to controls (p = 0.45). 350 kDa immunoblot bands representing WT full-length fibrillin-1 were present in human and mouse AH. A 418 kDa band representing mutant full-length fibrillin-1 was present only in Tsk mice. Lower molecular weight fibrillin-1 antibody-reactive bands were present in similar patterns in humans and mice. Certain bands (130 and 32 kDa) were elevated only in human POAG and Tsk mice (p ≤ 0.04 relative to controls) indicating discrete isoforms relevant to disease. In addition to sharing a phenotype, Tsk mice and human POAG subjects had common TGFβ and fibrillin-1 features in AH and also blood that are pertinent to understanding glaucoma pathogenesis.

HPLC-LED-Induced Fluorescence Analysis of Tear Fluids: An Objective Method for Primary Open Angle Glaucoma Diagnosis

PurposeThe study showcased the application of the lab-assembled HPLC-LED-IF system to analyze proteins in tear fluid samples collected from individuals diagnosed with primary open-angle glaucoma (POAG).MethodsClinical application of the said technique was evaluated by recording chromatograms of tear fluid samples from control and POAG subjects and by analyzing the protein profile using multivariate analysis. The data analysis methods involved are principal component analysis (PCA), Match/No-Match, and artificial neural network (ANN) based binary classification for disease diagnosis.ResultsMahalanobis distance and spectral residual values calculated using a standard calibration set of clinically confirmed POAG samples for the Match/No-Match test gave 86.9% sensitivity and 81.8% specificity. ANN with leaving one out procedure has given 87.1% sensitivity and 81.8% specificity.ConclusionThe results of the study revealed that the utilization of a 278 nm LED excitation in the HPLC system offers good sensitivity for detecting proteins at low concentrations allowing to obtain reliable protein profiles for the diagnosis of POAG.

Short-term Detection of Fast Progressors in Glaucoma: The Fast Progression Assessment through Clustered Evaluation (Fast-PACE) Study

To evaluate the performance of an intensive, clustered testing approach in identifying eyes with rapid glaucoma progression over 6 months in the Fast-PACE (Progression Assessment through Clustered Evaluation) study. Prospective cohort study. 125 eyes from 65 primary open-angle glaucoma (POAG) subjects. Subjects underwent two sets of 5 weekly visits (clusters) separated by an average of 6 months, then were followed with single visits every 6 months for an overall mean follow-up of 25 months (mean of 17 tests). Each visit consisted of testing with standard automated perimetry (SAP) 24-2 and 10-2, and spectral-domain optical coherence tomography (SD OCT). Progression was assessed using trend analyses of SAP mean deviation (MD) and retinal nerve fiber layer (RNFL) thickness. Generalized estimating equations were applied to adjust for correlations between eyes for confidence interval (CI) estimation and hypothesis testing. Diagnostic accuracy of the 6-month clustering period to identify progression detected during the overall follow-up. 19 of 125 eyes (15%, CI: 9%-24%) progressed based on SAP 24-2 MD over the 6-month clustering period. 14 eyes (11%, CI: 6%-20%) progressed on SAP 10-2 MD, and 16 (13%, CI:8%-21%) by RNFL thickness, with 30 of 125 eyes (24%, CI:16%-34%) progressing by function, structure, or both. Of the 35 eyes progressing during the overall follow-up, 25 had progressed during the 6-month clustering period, for a sensitivity of 71% (CI: 53%-85%). Of the 90 eyes that did not progress during the overall follow-up, 85 also did not progress during the 6-month period, for a specificity of 94% (CI: 88% - 98%). Of the 14 eyes considered fast progressors by SAP 24-2, 10-2 or SD OCT during the overall follow-up, 13 were identified as progressing during the 6-month cluster period, for a sensitivity of 93% (CI: 66% - 100%) for identifying fast progression with a specificity of 85% (CI: 77% - 90%). Clustered testing in the Fast-PACE study detected fast-progressing glaucoma eyes over six months. The methodology could be applied in clinical trials investigating interventions to slow glaucoma progression and may also be of value for short-term assessment of high-risk subjects.

A STUDY ON ASSOCIATION OF SYSTOLIC BLOOD PRESSURE, DIASTOLIC BLOOD PRESSURE, AND PULSE PRESSURE WITH INTRAOCULAR PRESSURE IN RELATION TO PRIMARY OPEN-ANGLE GLAUCOMA

Objective: This study aims to probe the relationship among pulse pressure (PP), systolic blood pressure (SBP) and diastolic blood pressure (DBP), and the intraocular pressure (IOP) in normal persons and primary open-angle glaucoma (POAG) patients. Design: This was an institution-based observational study. Methods: This study was conducted on 240 patients attending the ophthalmology department and glaucoma clinic of a tertiary hospital. Included subjects were asked about their ocular and systemic problems and undergone detailed examination of eyelids, conjunctiva, cornea, anterior chamber by slit lamp, visual acuity, refraction, and fundus examination. IOP was measured by Goldmann applanation tonometer. Blood pressure was measured by sphygmomanometer. Results: In this study, we found that SBP, DBP, PP, and IOP – both eyes were found to be higher in subjects with POAG than normal control subjects. Among these, differences in mean SBP, DBP, and IOP – both eyes between subjects with POAG and normal subjects were statistically significant. IOP was found to be positively correlated with SBP, DBP, and PP both in subjects with POAG as well as in normal subjects. Conclusion: Although involving a limited number of eyes, the key findings of the study suggest that IOP is positively correlated with PP, SBP, and DBP. This opens up the possibility of early detection of glaucoma patients with raised PP, SBP, and DBP.

Association between HSP-Specific T-Cell Counts and Retinal Nerve Fiber Layer Thickness in Patients with Primary Open-Angle Glaucoma.

Previous laboratory reports implicate heat shock protein (HSP)-specific T-cell responses in glaucoma pathogenesis; here, we aimed to provide direct clinical evidence by correlating systemic HSP-specific T-cell levels with glaucoma severity in patients with primary open-angle glaucoma (POAG). Cross-sectional case-control study. Thirty-two adult patients with POAG and 38 controls underwent blood draw and optic nerve imaging. Peripheral blood monocytes (PBMC) were stimulated in culture with HSP27, α-crystallin, a member of the small HSP family, or HSP60. Both interferon-γ (IFN-γ)+ CD4+ T helper type 1 cells (Th1) and transforming growth factor-β1 (TGF-β1)+ CD4+ regulatory T cells (Treg) were quantified by flow cytometry and presented as a percentage of total PBMC counts. Relevant cytokines were measured using enzyme-linked immunosorbent assays. Retinal nerve fiber layer thickness (RNFLT) was measured with OCT. Pearson's correlation (r) was used to assess correlations. Correlations of HSP-specific T-cell counts, and serum levels of corresponding cytokine levels with RNFLT. Patients with POAG (visual field mean deviation, -4.7 ± 4.0 dB) and controls were similar in age, gender, and body mass index. Moreover, 46.9% of POAG and 60.0% of control subjects had prior cataract surgery (P= 0.48). Although no significant difference in total nonstimulated CD4+ Th1 or Treg cells was detected, patients with POAG exhibited significantly higher frequencies of Th1 cells specific for HSP27, α-crystallin, or HSP60 than controls (7.3 ± 7.9% vs. 2.6 ± 2.0%, P= 0.004; 5.8 ± 2.7% vs. 1.8 ± 1.3%, P < 0.001; 13.2 ± 13.3 vs. 4.3 ± 5.2, P= 0.01; respectively), but similar Treg specific for the same HSPs compared with controls (P ≥ 0.10 for all). Concordantly, the serum levels of IFN-γ were higher in POAG than in controls (36.2 ± 12.1 pg/ml vs. 10.0 ± 4.3 pg/ml; P < 0.001), but TGF-β1 levels did not differ. Average RNFLT of both eyes negatively correlated with HSP27- and α-crystallin-specific Th1 cell counts, and IFN-γ levels in all subjects after adjusting for age (partial correlation coefficient r= -0.31, P= 0.03; r= -0.52, p= 0.002; r= -0.72, P < 0.001, respectively). Higher levels of HSP-specific Th1 cells are associated with thinner RNFLT in patients with POAG and control subjects. The significant inverse relationship between systemic HSP-specific Th1 cell count and RNFLT supports the role of these T cells in glaucomatous neurodegeneration. Proprietary or commercial disclosure may be found after the references.

Evaluation of microvascular changes in the retina and choriocapillaris in primary glaucoma and neuromyelitis optica spectrum disorder with optical coherence tomography angiography

BackgroundTo assess quantitatively the microvascular changes in the retina and choroid of healthy eyes, eyes of subjects with primary angle-closure glaucoma (PACG), primary open-angle glaucoma (POAG) and neuromyelitis optica spectrum disorder (NMOSD) using optical coherence tomography angiography (OCTA). MethodsA series of healthy individuals and subjects with PACG, POAG and NMOSD were recruited in this cross-sectional study. OCTA was performed to capture the optic nerve head and macula images and the vessel density (VD) and retinal nerve fiber layer (RNFL) thickness were quantified. The choriocapillary flow density (CFD) was calculated as the percentage of flow area to the whole selected area. ResultsA total of 68 PACG subjects, 25 POAG subjects, 51 NMOSD subjects and 37 healthy controls were enrolled. Significant decreases in peripapillary VD and RNFL thickness were observed in PACG (p < 0.001) and POAG (p < 0.001) eyes and also in NMOSD subjects with an optic neuritis history (p < 0.001) compared with healthy controls. Unaffected eyes in PACG and POAG subjects had lower baseline peripapillary VD than healthy controls (p = 0.002 and p = 0.011, respectively). PACG eyes showed a lower baseline CFD than POAG (p = 0.0027) and the CFD in early and advanced PACG eyes showed a significantly much more decrease than POAG (p = 0.002 and p < 0.001, respectively). ConclusionsThe peripapillary vessel density and RNFL thickness was reduced in glaucomatous and NMOSD eyes compared with healthy controls. PACG eyes showed a lower CFD than POAG and the distinct peripapillary and choriocapillaris microvasculature changes may be correlated to different PACG and POAG pathogenesis.

Doppler ultrasonography of ocular blood flow in non-glaucoma versus primary open angle glaucoma subjects at the university of Nigeria teaching hospital, Enugu

Purpose: To evaluate and compare the ocular blood flow in non-glaucoma versus primary open-angle glaucoma (POAG) subjects attending the ophthalmic clinic of University of Nigeria Teaching Hospital (UNTH) Enugu using Doppler ultrasonography. Methods: A cross-sectional comparative study was adopted. Fifty-Eight POAG and 58 non-glaucoma subjects were recruited. Information on their socio-demographic and clinical profiles was obtained via an interviewer-administered questionnaire. Ocular Doppler Imaging was performed on all the Subjects. Peak systolic volume, End diastolic volume, mean flow velocity and Resistive Index (RI) of the central retinal artery and ophthalmic artery were recorded. Data were analysed using the SPSS version 21. Person correlation was used to determine the relationship between the Doppler indices and demographic and clinical variables. The level of significance was at p &lt;0.05. Results: The subjects were mainly males, 71(61.7%), with an age range of 40 to 79 years. The POAG Subjects lived with glaucoma for 5.57±4.2 years, and mainly on medical treatment 52(89.7%) with beta-blockers and prostaglandin analogues. The RI was significantly higher (p=0.01) in POAG subjects. A significant positive relationship (P = 0.014) was observed between RI and intraocular pressure (IOP) of the POAG subjects. Conclusion: In POAG subjects, RI was significantly higher; as the IOP increased there was an increase in RI translating to a sub-optimal ocular blood flow. Interventions aimed at modifying the RI would therefore be synergistic with IOP lowering measures. Additionally, RI assessment may offer a new target for glaucoma case finding.

Evaluation of systemic IL-6 trans-signalling in patients with primary open-angle glaucoma

To evaluate systemic trans-signalling of interleukin (IL)-6 in patients with primary open-angle glaucoma (POAG). Fifty-one POAG patients and 47 matched healthy controls were enrolled. Serum concentrations of IL-6, sIL-6R, and sgp130 were quantified. Serum levels of IL-6, sIL-6R, and IL-6/sIL-6R ratios in the POAG group were significantly higher than those in control group, while only the sgp130/sIL-6R/IL-6 ratio was decreased. Among POAG subjects, advanced-stage patients exhibited significantly higher intraocular pressure (IOP), serum IL-6 and sgp130 levels, and IL-6/sIL-6R ratio than those in the early to moderate stage. The ROC curve analysis revealed that the IL-6 level and IL-6/sIL-6R ratio performed better than other parameters in diagnosing POAG and discriminating POAG severity. Serum IL-6 level was moderately correlated with IOP and C/D ratio, while a weak correlation was observed between sIL-6R levels with C/D ratio. IL-6 and sIL-6R levels were correlated with each other in POAG patients but not in healthy controls. Overstimulation of systemic IL-6 trans-signalling has been implicated in POAG.

Watching intense movies increase IOP of primary open angle glaucoma patients: A prospective study

To investigate intraocular pressure (IOP) changes while viewing smartphone movies under artificial intelligence (AI) monitoring. In all, 48 subjects were recruited from the glaucoma clinic of Xianyou maternal and child health hospital from January 2018 to March 2020. The research consisted of three parts. In part 1, movies rated by the Motion Picture Association of America (MPAA) were viewed via smartphones of various screen sizes under AI supervision for 90minutes, at a distance of 40cm. IOP and biological parameters including anterior chamber angle, Schlemm's canal (SC) cross-sectional area, heart rate, systolic and diastolic blood pressures (SBP and DBP) were measured and analyzed. In part 2, blue-blocking glasses (BB glasses) were worn to repeat the above experiments. In part 3, the efficacy of AI in decreasing attention loss was analyzed. In addition, results were analyzed to determine whether interval breaks, prompted by AI, prevented IOP from rising. In part 1, the mean IOP of primary open angle glaucoma (POAG) subjects' right eyes significantly increased by 4.828 and 4.974mmHg after watching R and NC-17movies, respectively. In their left eyes, it increased by 2.876 and 5.767 after watching R and NC-17movies, respectively. The maximum IOP difference was also increased by 4.782 and 4.510 on right and left eyes, respectively, after viewing NC-17 movies on a 6.1-inch screen. Furthermore, the SC became narrower, whereas heart rate, DBP and SBP increased in the POAG group. In addition, maximum IOP difference was significantly correlated with SC cross-sectional area, DBP and SBP in the POAG group. In part 2, symptom scores were improved by BB glasses; however, IOP was not decreased. In part 3, attention loss was significantly decreased by AI monitoring. On the contrary, AI also prevented IOP from rising via promoting interval rest. Watching adult movies (NC-17) can significantly increase the IOP of POAG patients. AI can prevent IOP from rising by promoting interval rest when viewing NC-17 movies.

Two-Year Outcomes of Trabeculectomy and Phacotrabeculectomy in Primary Open Angle Versus Primary Angle Closure Glaucoma.

Phacotrabeculectomy had a significantly lower 24-month failure rate than the isolated trabeculectomy in both the primary open angle glaucoma (POAG) and primary angle closure glaucoma (PACG) patients. The impact of adding phacoemulsification to trabeculectomy was found to be similar between the eyes with POAG and PACG. The purpose of this study is to compare the 2-year outcomes of primary mitomycin C-augmented combined phacotrabeculectomy (Phaco+Trab) with isolated trabeculectomy (Trab) in phakic patients with POAG and PACG. We retrospectively reviewed primary glaucoma patients who underwent mitomycin C-augmented trabeculectomy and completed 2 years of follow-up. Failure rate, postoperative intraocular pressure (IOP), percentage of IOP reduction, and the number of glaucoma medications at 24 months after surgery were compared between the Phaco+Trab and Trab groups. The study included 146 eyes of 121 patients; 74 underwent Trab and 72 underwent Phaco+Trab. POAG and PACG were present in 71 and 75 eyes, respectively. Defining a failure with IOP criteria of >18mmHg or IOP reduction of <30%, the failure rates were 42% and 62% for Phaco+Trab and Trab, respectively. The Phaco+Trab group had a significantly lower failure rate than the Trab group for all subjects [risk ratio (RR): 0.60, 95% CI, 0.44-0.81, P =0.001], POAG subgroup (RR: 0.61, 95% CI, 0.41-0.93, P =0.02), and PACG subgroup (RR: 0.53, 95% CI, 0.33-0.86, P =0.01). Differences in the postoperative IOP, percentage of IOP reduction, and number of glaucoma medications were not significant between the 2 groups for all subjects, POAG, and PACG (all P >0.05). The magnitude of the effects of adding phacoemulsification to the trabeculectomy was comparable for the POAG and PACG groups, for each outcome (all P >0.05). The final 24-month failure rate in the Phaco+Trab group was lower than that in the Trab group in both the POAG and PACG subjects. The impact of adding phacoemulsification to trabeculectomy was found to be similar between the eyes with POAG and PACG.

Prevalence of Myocilin Gene Mutation in Adult-Onset Primary Open Angle Glaucoma and Non-Glaucoma Subjects Who Are Indigenes of Rivers State, Nigeria

Background: Glaucoma is the leading cause of irreversible blindness incapacitating over 80 million people worldwide. Several pathogenetic mechanisms have been postulated to explain the optic nerve damage that occur in POAG among which genetic predisposition is prominent. Gene-Linkage-based studies have identified genes associated with POAG: Myocilin, Optineurin, WDR36, Tank-Binding Kinase (TBK1) and APbb-2. Objective: To investigate the prevalence of myocilin gene mutation in adult-onset POAG patients and non-glaucoma subjects who are indigenes of Rivers State. Methodology: In this comparative cross-sectional study, 393 POAG patients attending the Glaucoma Clinic of UPTH were compared with 393 age and sex-matched phenotypically normal participants. Clinical assessment combined with findings from clinical records was used. Venous blood was obtained for genomic analyses. Extracted DNA was sequenced with specific primers for myocilin and polymerase chain reaction. Zymo-Bead Genomic DNA kit protocol was used to detect allelic differences. Results: Total of 786 participants participated in the study. The mean age was 59.8 ± 11.8 years. The prevalence of myocilin gene mutation (MYOC) in the study population was 5.3%, in the POAG group was 8.4%, and 2.3% in the non-glaucoma group. This observed difference was statistically significant (p = 0.001). Location of the mutant myocilin gene was in GLC1A 171638779, 171638703, 171638610 and 171638608. Conclusion: Mutations in myocilin gene are associated with adult-onset POAG in Rivers State. Its relevance as a biomarker for diagnosis of adult-onset POAG needs further investigations.

DESCRIBING THE EFFECTS OF PRIMARY OPEN ANGLE GLAUCOMA ON MACULA USING SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY IN CENTRAL INDIA

Introduction: Primary open-angle glaucoma is a silent predator of sight, killing retinal ganglion cells (RGCs), and leads to characteristic optic nerve head (ONH) changes and visual field (VF) defects. The conventional methods of diagnosis include clinical examination and perimetry. However, by these at the time of diagnosis, a substantial loss of RGCs has already occurred. Spectral domain optical coherence tomography (SD-OCT) allows quantitative measurements of various parameters of the retina. This tool may be utilized for selective measurement of macular parameters to make an early diagnosis of primary open angle glaucoma (POAG). Methods: In 6 months of study, a total of 81 eyes of 51 subjects underwent SD-OCT measurements, that is, 49 eyes of 35 POAG subjects and 32 eyes of 16 age-matched healthy subjects, to record all measurable macular parameters, namely, macular thickness (MT)-central, average, in all sectors of the inner and outer circle of early treatment of diabetic retinopathy study (ETDRS) macular map; macular volume, ganglion cell-inner plexiform layer (GC-IPL) thickness-in all sectors; succeeded by statistical calculations using the unpaired t-test to calculate two-tailed p-value which is significant when its value is &lt;0.05. Results: As an observation the average MT, MT in the inferior and temporal sector of the inner circle of the ETDRS macular map, that in the inferior sector of the outer circle, minimum GC-IPL thickness, and GC-IPL thickness in all sectors were all significantly reduced in POAG eyes than healthy eyes. Whereas central MT, average GC-IPL thickness, macular volume, and MT in few sectors of the inner and outer circle of the ETDRS macular map proved to bear an insignificant change of POAG. Conclusion: In this study, the greatest impact of POAG on macula was discovered in the GC-IPL layer and MT in the inferior sector of inner and outer ring which might serve the purpose of diagnosis of POAG apart from the established parameters of RNFL and ONH.

The Influence of Near Vision Tasks on Intraocular Pressure in Normal Subjects and Glaucoma Patients.

To investigate the effect of static accommodative tasks on intraocular pressure (IOP) of glaucomatous and normal eyes. Four groups of subjects categorized as primary open-angle glaucoma (POAG), primary angle-closure suspects (PACS), normal age-matched controls, and normal young adults (NYA; age 40 years) were enrolled. The baseline IOPs were measured after the subjects were looking at a distant target for 15 min. Static accommodation was obtained by execution of near vision tasks (reading at 33 cm in daylight [300 lux] for 60 min). IOPs were measured at 15, 30, 45, and 60 min intervals while accommodating and then measured again after 15 min of relaxing accommodation while looking at a distant target. One-hundred and eighteen eyes of 98 subjects were recruited. The study groups consisted of the following categories: 25 POAG (46 eyes), 24 PACS (47 eyes), 25 matched controls (50 eyes), and 24 NYA (48 eyes). Within all groups, the mean IOP decreased throughout the accommodation period at all time points. Maximum IOP reduction after accommodation was detected at the 30-min time among the POAG subjects, at the 45-min time in the PACS and matched control groups, and at 15 min after the relaxation of accommodation in the NYA group. IOP reduction levels showed no statistically significant difference among POAG, PACS, and the normal matched groups in their response to accommodation. However, NYA had significantly lower IOP and greater IOP reduction after the resting period (relaxation of accommodation). Static accommodative tasks can significantly reduce IOP in normal, POAG, and PACS individuals. Encouraging glaucoma patients to practice periodical near vision tasks could be viewed as an adjunctive measure for glaucoma management.

Retinal Oxygen Extraction in Patients with Primary Open-Angle Glaucoma.

Objective: To compare total retinal oxygen extraction between patients with primary open-angle glaucoma (POAG) and healthy control subjects. Design: A prospective, single-center, cross-sectional, case–control study performed at the Medical University of Vienna. Subjects: Forty patients with POAG and 40 age- and sex-matched control subjects. Methods: Total retinal blood flow was measured using Doppler optical coherence tomography (OCT). Retinal arterial and venous oxygen saturation was measured using reflectance spectroscopy. From these parameters, oxygen content in the retinal arterial and venous circulation as well as total retinal oxygen extraction were calculated. Results: Total retinal blood flow was lower in POAG (25.2 ± 6.7 µL/min) as compared to healthy control subjects (35.6 ± 8.3 µL/min, p < 0.001). Retinal arterial oxygen content was not different between the two groups (0.18 ± 0.01 mL(O2)/mL in both groups, p < 0.761), but retinal venous oxygen content was higher in POAG (0.15 ± 0.01 mL(O2)/mL) than in healthy controls (0.14 ± 0.01 mL(O2)/mL p < 0.001). Accordingly, retinal oxygen extraction was reduced in POAG (0.8 ± 0.3 µL(O2)/min as compared to healthy controls: 1.4 ± 0.4 µL(O2)/min, p < 0.001). There was a significant association between total retinal blood flow and total retinal oxygen extraction with measures of structural and functional damage (p < 0.001 each). Conclusions: This study indicates that POAG is associated with a reduction in total retinal oxygen extraction linked to structural and functional damage of the disease. Since the technology is non-invasive, it allows for longitudinal studies investigating to which degree low retinal oxygen extraction is linked to the progression of the disease.

DISCRIMINATION OF EYES WITH PRIMARY OPEN-ANGLE GLAUCOMA FROM NORMAL USING MACULAR GC-IPL THICKNESS

Objective: Primary open-angle glaucoma (POAG), a neuro-ophthalmological disease, is a condition of slowly progressive loss of retinal ganglion cells which are evident as characteristic optic nerve head vicissitudes and visual field defects, only after death of more than 40% of cells. This huge loss when witnessed is started to treat only if the patient approaches an ophthalmologist with a significant complaint, leading to optic nerve head examination, which means being an asymptomatic disease, it is usually left undiagnosed until advanced. An additional system of diagnosis of the disease earlier in the stage can aid reduce the burden of the blindness of POAG. Methods: Among a total of 62 eyes of 31 subjects, 40 eyes of 20 POAG subjects, and 22 eyes of 11 age-matched healthy subjects were recruited. All of them underwent Spectral Domain Optical Coherence Tomography macular and optic disk scans to note macular ganglion cell–inner plexiform layer (mGCIPL) and retinal nerve fiber layer (RNFL) thicknesses. Statistical analysis was did using an unpaired t-test and calculating a two-tailed p value, in which the significance was indicated by p&lt;0.05. Results: Similar to peripapillary RNFL thickness, the mGCIPL parameters, that is, minimum GCIPL thickness and GCIPL thickness in all sectors decreased significantly in POAG eyes to be able to discriminate them from normal. mGCIPL and RNFL thickness decreased as the severity of glaucoma increased. Conclusion: The minimum GCIPL thickness and that in all sectors can discriminate POAG eyes from healthy eyes significantly and has comparable performance to that of peripapillary RNFL thickness.

Distribution of ocular perfusion pressure and its relationship with intraocular pressure in patients with primary open angle glaucoma in Enugu, South East, Nigeria.

Ocular perfusion pressure (OPP) has been suggested as a possible risk factor for the development and progression of primary open angle glaucoma (POAG). To determine the distribution of OPP and its relationship with intraocular pressure (IOP) in Nigerian patients with POAG. : A descriptive and comparative survey was adopted. A total of 120 subjects, 60 newly diagnosed POAG and 60 non-glaucomatous (NG) subjects, aged 40 years and above, who attended the ophthalmic clinic of University of Nigeria Teaching Hospital Enugu were recruited over a six-month period in 2019. All the subjects had ocular examination, blood pressure and IOP measurements. Statistical package for social sciences software version 25 was used for data analysis. Chi-square test, independent samples t-test, and Mann-Whitney U test were used for comparison while Pearson correlation and simple linear regression were used to ascertain the relationship. A P value of <0.05 was considered significant. The mean age of the participants was 57.9 + 11.9 years. The mean OPP was found to be significantly lower in the POAG subjects (Right eye, R = 43.6 ± 12.6, Left eye, L = 41.9 ± 13.3) mmHg compared with the NG group (R = 53.9 ± 10.9, L = 53.7 ± 10.9) mmHg (p < 0.001 for both eyes). A significant inverse relationship was observed between OPP and IOP in POAG subjects (p < 0.001), while there was none in NG subjects. OPP was lower in POAG subjects than in NG subjects. The observed relationship suggests that reduced OPP may play a role in the development of POAG.

Plasma levels of sirtuin and adiponectin in patients with primary open-angle glaucoma, exfoliative glaucoma, and healthy controls.

To compare plasma levels of sirtuin 1 (SIRT1) and adiponectin (APN) in patients with primary open-angle glaucoma (POAG), exfoliative glaucoma (XFG), and healthy control subjects. This prospective case-control study collected plasma samples from 118 participants. All subjects underwent a comprehensive ophthalmologic examination before the acquisition of a plasma sample. Plasma samples were obtained from 40 POAG, 38 XFG, and 40 healthy control subjects without any evidence of systemic or ocular disease. Serum SIRT1 and APN levels were estimated by an enzyme-linked immunosorbent assay, ELISA (Elabscience, Houston, USA) method. Statistical analysis of results relied on Kolmogorov-Smirnov, Kruskal-Wallis, Chi-square, analysis of variance (ANOVA) tests, and linear regression analysis, where appropriate. A significant decrease in SIRT1 levels was observed in POAG patients compared to healthy controls (p = 0.004, Dunn's test). In contrast, no difference was detected between XFG and POAG patients or healthy controls (p = 0.32 and p = 0.34, respectively, Dunn's test). There was no significant difference in plasma APN levels between the three groups under investigation (p = 0.59, ANOVA). Alterations in serum level of SIRT1 may suggest a possible role in POAG via potential effects in neuroprotection and oxidative stress.

New possibilities for the glaucoma diagnostics using the synchronous fluorescence spectra of tear fluid

Tear fluid represents a biological material with immense potential in the diagnostics of ocular diseases. Glaucoma is a vision-threatening ocular disease with a great need to speed up and simplify the diagnostic process. For this purpose, tear fluid changes among primary open-angle glaucoma, suspected glaucoma, ocular hypertension, and healthy control subjects were analyzed using the ratio between two peaks in the wavelength range of 210–300 nm at the section of wavelength interval of Δλ = 110 on the synchronous fluorescence spectra and by second derivative synchronous fluorescence spectroscopy. The location of minimum and maximum in the wavelength range 200–260 nm at the section of wavelength interval of Δλ = 110 nm differed between the groups of subjects showing the highest difference in healthy controls (17.5 ± 1.9) followed by ocular hypertension (16.5 ± 1.3), and lowest in suspected glaucoma (14.5 ± 1.7) and primary open-angle glaucoma (14.5 ± 3.9). This factor could serve as a novel discriminative parameter for distinguishing between the groups of subjects. Overall, second derivative synchronous fluorescence spectroscopy might be used for monitoring these patients.

Intra-population differences of apolipoproteins in the aqueous humor

BackgroundEvidence suggests that proteins related to lipid metabolism, such as apolipoproteins, play an important role in the maintenance of normal vision. While several members of the apolipoprotein family are abundant in human aqueous humor (AH), their study remains difficult due to the AH’s small volume, low protein concentration, and the invasive nature of sample collection. In this study, we report the use of Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) to discover associations between AH apolipoproteins and race, gender, and ocular structure in patients with and without primary open angle glaucoma (POAG).MethodsAH samples were collected from 231 patients undergoing phacoemulsification or glaucoma incisional surgery at the Medical College of Georgia, Augusta University and subsequently analyzed via LC-MS/MS. The number of peptide spectrum matches (PSMs) for each protein was used as a semi-quantitative measure of relative protein levels. Parameters related to ocular structure were determined using Optical Coherence Tomography (OCT) and Heidelberg Retinal Tomography (HRT). These data sets were probed for relationships between apolipoprotein levels and POAG, demographics (gender and race), and ocular structure.ResultsA total of ten apolipoproteins were detected in the 231 collected AH samples, with six detected in 100% of the samples, one detected in almost 57% of the samples and three detected in less than 10% of the samples. The levels of APOA1, APOC3, and APOD were higher among POAG subjects. Stratification by gender and race revealed demographic-specific variations. The levels of five apolipoproteins (APOA1, APOA2, APOA4, APOC3, and APOD) were higher in female POAG patients, whereas no apolipoprotein levels were altered in male POAG patients. The levels of APOA1, APOA2, APOA4, and APOD were increased in glaucomatous African American patients, whereas APOE and APOH levels were decreased in glaucomatous Caucasian patients. We also found distinct associations between apolipoprotein levels and OCT and HRT parameters in patients with and without POAG.ConclusionsThe intra-population variation in apolipoprotein levels highlights the heterogeneity of glaucoma as a disease, suggesting the importance of personalized treatments. Gender and race-specific alterations may be associated with higher risks of POAG in females and members of the African American population.