Central Visual Field Defects in Patients with Distinct Glaucomatous Optic Disc Phenotypes

Comparative analysis of the optic nerve microvasculature between different optic disc phenotypes of normal-tension glaucoma patients

PURPOSE

To determine whether the optic nerve head (ONH) and parapapillary choroidal vessel density (VD), measured by optical coherence tomography angiography (OCTA), differ between two common optic disc phenotypes (ODPs) in normal-tension glaucoma (NTG).

DESIGN

A retrospective case-control study.

METHODS

This cross-sectional study analyzed 100 NTG patients with visual field (VF) loss confined to a single hemifield (50 eyes with focal ischemic [FI] ODP and 50 eyes with myopic glaucomatous [MG] ODP, matched for age [≤ 10 years] and VF severity [mean deviation ≤ 1 dB]) as well as 50 healthy eyes. Using OCTA, ONH VD (ONH-VD) was evaluated on a 4.5 × 4.5 mm ONH en-face image using the whole-signal mode. The parapapillary choroidal VD (pCVD) was measured on en-face choroidal layer image within the entire β-parapapillary atrophy (β-PPA) zone using imageJ software. The ONH-VD and pCVD were compared among the three groups. The relationships between ONH-VD and pCVD outcomes and various clinical variables were assessed using linear regression analyses.

RESULTS

The average ONH-VD and pCVD were significantly lower in eyes with MG ODPs than those with FI ODPs (56.9% vs. 60.4%, 67.1% vs. 71.8%; both P < 0.05). Multivariable linear regression analysis indicated that MG ODP, lower peripapillary retinal nerve fiber layer thickness and VD in the hemiretina, corresponding to hemifield VF loss, in addition to the presence of choroidal microvasculature dropout, were significantly associated with lower ONH-VD and pCVD (P < 0.05).

CONCLUSIONS

The OCTA-measured ONH-VD and pCVD are significantly lower in eyes with MG ODPs rather than FI ODPs. MG ODP is independently associated with lower ONH-VD and pCVD in NTG eyes.

Peripapillary Versus Macular Thinning to Detect Progression According to Initial Visual Field Loss Location in Normal-Tension Glaucoma

PURPOSE

To investigate the predictive capabilities of peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell-inner plexiform layer (mGCIPL) thinning to detect visual field (VF) progression in normal-tension glaucoma patients with an initial parafoveal scotoma (IPFS) or nasal step (INS).

DESIGN

Retrospective cohort study.

METHODS

A total of 185 early-stage glaucoma eyes, followed for 10 years, were retrospectively stratified into IPFS and INS groups. Progressive pRNFL and mGCIPL thinning were assessed using spectral-domain optical coherence tomography and VF progression using both event- or trend-based analysis. Kaplan-Meier survival analysis compared VF survival in each VF phenotype with or without progressive pRNFL and mGCIPL thinning. Cox proportional regression analysis identified VF progression factors.

RESULTS

VF progression was detected in 42 IPFS (n = 86) and 47 INS (n = 99) eyes. Among VF progressors, pRNFL thinning was significantly faster in INS group compared to IPFS group (P < .01), while mGCIPL thinning was similar (P = .16). At 5 years, eyes with progressive mGCIPL thinning showed significantly lower VF survival in both VF phenotypes (all P < .05). Progressive pRNFL thinning showed significantly lower VF survival only in INS eyes (P = .015). Cox multivariate regression revealed that mGCIPL thinning predicted subsequent VF progression in IPFS eyes, while mGCIPL and pRNFL thinning had significant associations with VF progression in INS eyes.

CONCLUSIONS

mGCIPL outperforms pRNFL at early follow-up in detecting VF progression in IPFS eyes but not INS eyes. Appropriate selection of structural parameters (mGCIPL vs. pRNFL) maximizes early VF progression detection according to initial VF defect location.

Central visual field in glaucoma: An updated review

Evaluation of central vision in glaucoma is important due to its impact on patients' quality of life and activities of daily living such as reading, driving, and walking. The 10-2 visual field (VF) assessment remains a mainstay in the functional analysis of central vision in glaucoma diagnosis and progression. However, it may be underutilized in clinical practice. Monitoring of disease progression especially in advanced cases, glaucoma evaluation in certain ocular disorders such as high myopia, disc hemorrhage, low corneal hysteresis, and certain optic disc phenotypes, as well as earlier detection of central VF damage, are certain conditions where additional monitoring with the 10-2 pattern may provide complementary clinical information to the commonly utilized 24-2 pattern. In addition, the development of artificial intelligence techniques may assist clinicians to most effectively allocate limited resources by identifying more risk factors to central VF damage. In this study, we aimed to determine specific patient characteristics that make central VF damage more likely and to assess the benefit of incorporating the 10-2 VF in various clinical settings.

Genetic Aspects of Glaucoma: An Updated Review

Glaucoma is a group of diverse diseases characterized by cupping of the optic nerve head due to the loss of retinal ganglion cells. It is the most common cause of irreversible blindness throughout the world; therefore, its timely diagnosis and early detection through an ophthalmological examination are very important. We, herein, present the information on the epidemiology, pathophysiology, clinical diagnosis, and treatment of glaucoma. We also emphasize the investigations of the last decades that have allowed identifying numerous genes and susceptibility genetic factors. We have also described in detail the genes whose mutations cause or contribute to the development of the disease.

Phenotypic expressions of the optic disc in primary open-angle glaucoma

BACKGROUND

Which phenotypes are we able to recognize in the optic nerve of patients with primary open angle glaucoma?

METHODS

Retrospective interventional case series. 885 eyes from 885 patients at an outpatient tertiary care centre who met specified criteria for POAG were included. Disc photographs were classified by three glaucoma specialists into the following phenotypes according to their predominant characteristics: (1) concentric rim thinning, (2) focal rim thinning, (3) acquired pit of the optic nerve (APON), (4) tilted, (5) extensive peripapillary atrophy (PPA), and (6) broad rim thinning. Demographic, medical, and ocular data were collected. Kruskal-Wallis was used as a non-parametric test and pairwise comparison was performed by using Wilcoxon rank sum test corrected.

RESULTS

Phenotypic distribution was as follows: 398(45%) focal thinning, 153(18%) concentric thinning, 153(17%) broad thinning, 109(12%) tilted, 47(5%) extensive PPA and 25(3%) APON. Phenotypic traits of interest included a higher proportion of female patients with the focal thinning phenotype (p = 0.015); myopia (p = 0.000), Asian race (OR: 8.8, p = 0.000), and younger age (p = 0.000) were associated with the tilted phenotype; the concentric thinning patients had thicker RNFL (p = 0.000), higher MD (p = 0.008) and lower PSD (p = 0.043) than broad thinning, despite no difference in disc sizes (p = 0.849). The focal thinning group had a localized VF pattern with high PSD compared to concentric thinning (p = 0.005).

CONCLUSION

We report six phenotypic classifications of POAG patients with demographic and ocular differences between phenotypes. Future refinement of phenotypes should allow enhanced identification of genetic associations and improved individualization of patient care.

Advances in understanding glaucoma pathogenesis: A multifaceted molecular approach for clinician scientists

Glaucoma, a leading cause of irreversible blindness worldwide, is a spectrum of neurodegenerative diseases characterized by the gradual deterioration of retinal ganglion cells (RGCs) and optic neuropathy. With complex etiology, glaucoma's major risk factors include elevated intraocular pressure (IOP), advanced age, ethnicity, systemic vascular factors, and genetic predisposition. By 2040, glaucoma is expected to affect over 110 million individuals aged 40 to 80, posing a significant economic burden. Glaucoma can be classified into open-angle, angle-closure, and developmental subtypes, with primary and secondary forms. The disease often progresses silently, gradually impairing the visual field (VF) until it reaches an advanced stage. Understanding the abnormal functional changes associated with glaucoma at the tissue, cellular, molecular, and genetic levels is crucial for comprehending its pathogenesis. This review examines the published data from the past two decades to shed light on the biological mechanisms underlying glaucoma development. The most evident factors in the development of glaucomatous optic neuropathy include elevated IOP, aging, genetic influences, followed by impaired ocular blood flow regulation. These factors are interconnected processes that lead to optic nerve damage, compromised circulation, and structural changes in glial and connective tissues. Contributing factors involve extracellular matrix remodeling, excitotoxicity, nitric oxide, oxidative stress, and neuroinflammation. Ultimately, all types of glaucoma result in RGC dysfunction and loss, causing irreversible visual impairment. While our understanding of glaucoma pathogenesis is evolving, further research is crucial for a comprehensive understanding of glaucoma pathogenesis and the development of effective treatments.

Lamina Cribrosa Morphology in Normal Tension Glaucoma According to the Location of Visual Field Defects

PRCIS

The morphologic alterations in lamina cribrosa (LC) may be related to the location of visual field (VF) defects.

PURPOSE

The aim of this study was to investigate morphologic differences in the LC in normal tension glaucoma (NTG) according to the location of VF defects.

DESIGN

This study was a retrospective, cross-sectional study.

METHODS

Ninety-six eyes of 96 patients with NTG were included in this study. The patients were divided into 2 groups according to the location of VF defects [parafoveal scotoma (PFS) and peripheral nasal step (PNS)]. All patients underwent an optical coherence tomography of the optic disc and macula using swept-source optical coherence tomography (DRI-OCT Triton; Topcon, Tokyo, Japan). The parameters of the optic disc, macula, LC, and connective tissues were compared between the groups. The relationships between the LC parameters and other structures were analyzed.

RESULTS

The temporal peripapillary retinal nerve fiber layer, average macular ganglion cell-inner plexiform layer, and average macular ganglion cell complex were significantly thinner in the PFS than in the PNS group ( P <0.001, P <0.001, and P =0.012, respectively). The PFS group showed a more glaucomatous LC morphology with a smaller lamina cribrosa-global shape index (LC-GSI, P =0.047), more LC defects ( P =0.034), and thinner LC ( P =0.021) than the PNS group. LC-GSI was significantly correlated with LC thickness ( P =0.011) but not with LC depth ( P =0.149).

CONCLUSIONS

In patients with NTG, those with initial PFS showed a more glaucomatous LC morphology than those with initial PNS. The morphologic differences in LC may be related to the location of the VF defects.

Macular Optical Coherence Tomography Imaging in Glaucoma

The advent of spectral-domain optical coherence tomography has played a transformative role in posterior segment imaging of the eye. Traditionally, images of the optic nerve head and the peripapillary area have been used to evaluate the structural changes associated with glaucoma. Recently, there is growing evidence in the literature supporting the use of macular spectral-domain optical coherence tomography as a complementary tool for clinical evaluation and research purposes in glaucoma. Containing more than 50% of retinal ganglion cells in a multilayered pattern, macula is shown to be affected even at the earliest stages of glaucomatous structural damage. Risk assessment for glaucoma progression, earlier detection of glaucomatous structural damage, monitoring of glaucoma especially in advanced cases, and glaucoma evaluation in certain ocular conditions including eyes with high myopia, positive history of disc hemorrhage, and certain optic disc phenotypes are specific domains where macular imaging yields complementary information compared to optic nerve head and peripapillary evaluation using optical coherence tomography. Moreover, the development of artificial intelligence models in data analysis has enabled a tremendous opportunity to create an integrated representation of structural and functional alterations observed in glaucoma. In this study, we aimed at providing a brief review of the main clinical applications and future potential utility of macular spectral-domain optical coherence tomography in glaucoma.

Comparison of 10-2 and 24-2C Test Grids for Identifying Central Visual Field Defects in Glaucoma and Suspect Patients

PURPOSE

To compare the ability of 24-2C and 10-2 test grids in measuring visual field global indices, identifying central visual field defects, and facilitating macular structure-function analysis with OCT scans in glaucoma and glaucoma suspect patients.

DESIGN

Prospective, cross-sectional study.

PARTICIPANTS

One eye from 131 glaucoma and 57 glaucoma suspect patients recruited from a referral-only, university-based glaucoma clinic.

METHODS

Each subject underwent perimetric testing using 24-2C SITA-Faster and 10-2 SITA-Fast in random order, and Cirrus OCT macular imaging (Ganglion Cell Analysis) for structure-function correlations.

MAIN OUTCOME MEASURES

Visual field global indices (mean deviation, pattern standard deviation, binarized "cluster" pass/fail, and central mean sensitivity), number and proportion of visual field defects, and structure-function concordance with the Cirrus OCT deviation map following visual field location displacement for correspondence with underlying retinal ganglion cell position.

RESULTS

Global indices (mean deviation, pattern standard deviation, and central mean sensitivity) were similar between both grids. The 10-2 detected more defects compared with the 24-2C (P < 0.0001 for all patients, P = 0.006 for glaucoma patients). This was preserved when analyzing the proportion of defects in the central visual field for all patients (P = 0.02) but was not significantly different for glaucoma patients (P = 0.051). The 10-2 identified more central "clusters" of 2+ contiguous points of deficit (P < 0.0001). Structure-function comparisons performed at locations where visual field and OCT test locations were colocalized revealed greater concordance of structural and functional deficits using the 10-2 (P < 0.0001). The 10-2 took a median of 201 seconds, and the 24-2C took a median of 154 seconds, corresponding to the different thresholding algorithms.

CONCLUSIONS

The 24-2C and 10-2 test grids return similar global indices of visual field performance and proportionally similar amounts of central visual field loss. The additional points in the 10-2 grid return more "clusters" of defects and a greater rate of structure-function concordance compared with the 24-2C test grid. Thus, the 24-2C can identify the presence of a clustered central visual field defect using similar probability criteria, whereas the 10-2 may be more useful in comprehensively characterizing the defect and predicting central visual function.

Incidence of Dementia in Patients With Open-angle Glaucoma: A Population-based Study

PRECIS

In this population-based study of 509 open-angle glaucoma (OAG) patients over a 36-year period, we identified a decreased rate of developing dementia compared with the rate in the general population.

PURPOSE

The aim was to determine the incidence of dementia and Alzheimer disease (AD) among patients with OAG.

PATIENTS AND METHODS

Retrospective, population-based cohort study. All residents of Olmsted County, Minnesota (≥40 y) who were diagnosed with OAG between January 1, 1965 and December 31, 2000, were eligible for inclusion in this study. A total of 509 patients were included over the 36-year period. The cumulative probability of developing dementia was calculated and compared with the population risk of dementia.

RESULTS

Of the 509 patients included, 300 (58.9%) were female, the median age was 67.5 years, and 278 patients (54.6%) had primary OAG. Other subgroups were pseudoexfoliation in 15.1%, treated ocular hypertension in 14.1%, normal tension glaucoma in 10.6%, and pigmentary glaucoma in 5.5% of the patients. Respectively, 118 (23.0%) and 99 (19.4%) patients developed dementia and AD. The 10-year cumulative probability of developing dementia and AD was 12.0% and 9.9%, with a 95% confidence interval of 9.3%-15.3% and 7.5%-13%, respectively. The observed 10-year incidence of dementia and AD were significantly lower than the expected population incidence (19.0% and 19.0%; P<0.001). Older age at diagnosis of glaucoma was a strong predictor for the development of dementia by multivariate analysis (hazard ratio: 3.31, 95% confidence interval: 2.61-4.20, P<0.001).

CONCLUSION

The risk of developing dementia or AD was decreased in OAG patients compared with the general population. OAG with onset at a later age may present as a different etiopathogenetic entity compared with onset at a younger age, and represent the optic nerve findings of generalized neurodegenerative processes.