Application of optical coherence tomography in glaucoma suspect eyes

The Comparison of Age-related Change in Retinal Nerve Fiber Layer and Ganglion Cell Complex Thicknesses between Glaucoma Suspects and Healthy Individuals

Aim

The purpose of this study is to investigate the difference of change in the retinal nerve fiber layer (RNFL) and the ganglion cell complex (GCC) thickness according to age in glaucoma suspect individuals and healthy subjects.

Materials and methods

Thicknesses of RNFL and GCC were measured with spectral domain optical coherence tomography (SD-OCT) in glaucoma-suspected individuals and healthy subjects. The differences in age, overall mean, four quadrants, and 12 clock-hour sectors of RNFL and overall mean, superior half, and inferior half GCC thicknesses between glaucoma suspects and healthy participants were analyzed and compared using linear regression analyses.

Results

There were 201 glaucoma-suspect individuals and 121 healthy subjects with a mean age of 38.89 and 40.26 years, respectively (p = 0.27). The mean overall RNFL thickness was found to be 97.76 and 97.43 µm in healthy individuals and glaucoma suspects (p = 0.72). The mean overall GCC thickness was found to be 111.30 and 104.67 µm in healthy individuals and glaucoma suspects, respectively (p < 0.001). There was a 0.11 µm decrease per year found in overall GCC thickness in glaucoma suspects and 0.23 µm decreases per year in overall GCC thickness in healthy individuals (p < 0.001). There was a 0.02 µm decrease per year found in overall RNFL thickness in glaucoma suspects and a 0.29 µm decrease per year in overall RNFL thickness in healthy individuals (p < 0.001). However, these per-year decreases in GCC thickness glaucoma suspects and healthy individuals were not found to be statistically significant (p = 0.21); on the other hand, this difference for RNFL thickness was significant (p < 0.001).

Conclusion

It was found that the thicknesses of RNFL and GCC were different between glaucoma suspects and healthy individuals. However, age-related decay in the RNFL and GCC thicknesses was not uniform in healthy individuals and glaucoma suspects.

Clinical significance

It was found that the RNFL thickness and GCC thickness were lower in glaucoma suspects than in healthy controls eyes. However, an age-related decrease of RNFL and GCC thicknesses were found to be less in glaucoma suspects compared with healthy controls.

How to cite this article

Firatli G, Elibol A, Altinbas E, et al. The Comparison of Age-related Change in Retinal Nerve Fiber Layer and Ganglion Cell Complex Thicknesses between Glaucoma Suspects and Healthy Individuals. J Curr Glaucoma Pract 2023;17(1):22-29.

Optical Coherence Tomography Evaluation of Peripapillary and Macular Structure Changes in Pre-perimetric Glaucoma, Early Perimetric Glaucoma, and Ocular Hypertension: A Systematic Review and Meta-Analysis

Background: This study aimed to assess the differences in the average and sectoral peripapillary retinal nerve fiber layer (pRNFL), macular ganglion cell plus inner plexiform layer (mGCIPL), and macular ganglion cell complex (mGCC) thickness using optical coherence tomography (OCT) in patients with pre-perimetric glaucoma (PPG) compared to those with early perimetric glaucoma (EG) and ocular hypertension (OHT).

Methods: A comprehensive literature search of the PubMed database, the Cochrane Library, and Embase was performed from inception to March 2021. The weighted mean difference (WMD) with the 95% confidence interval (CI) was pooled for continuous outcomes.

Results: Twenty-three cross-sectional studies comprising 2,574 eyes (1,101 PPG eyes, 1,233 EG eyes, and 240 OHT eyes) were included in the systematic review and meta-analysis. The pooled results demonstrated that the average pRNFL (WMD = 8.22, 95% CI = 6.32–10.12, P < 0.00001), mGCIPL (WMD = 4.83, 95% CI = 3.43–6.23, P < 0.00001), and mGCC (WMD = 7.19, 95% CI = 4.52–9.85, P < 0.00001) were significantly thinner in patients with EG than in those with PPG. The sectoral thickness of pRNFL, mGCIPL, and mGCC were also significantly lower in the EG eyes. In addition, the average pRNFL and mGCC were significantly thinner in the PPG eyes than those in the OHT eyes (pRNFL: WMD = −8.57, 95% CI = −9.88 to −7.27, P < 0.00001; mGCC: WMD = −3.23, 95% CI = −6.03 to −0.44, P = 0.02). Similarly, the sectoral pRNFL and mGCC were also significantly thinner in the PPG eyes than those in the OHT eyes.

Conclusion: OCT-based measurements of peripapillary and macular structural alterations can be used to distinguish PPG from EG and OHT, which can help understand the pathophysiology of glaucoma at earlier stages. Studies that employ clock hour classification methods and longitudinal studies are needed to verify our findings.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=239798 CRD42021239798

Optical coherence tomography use in idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) is a condition in which elevated pressure in the cerebrospinal fluid can lead to optic nerve head (ONH) dysfunction and subsequent visual impairment. Physicians are currently limited in their ability to monitor and manage this condition, as clinical symptoms and exam findings are often delayed in response to changes in intracranial pressure. In order to find other biomarkers of disease, researchers are using imaging modalities such as optical coherence tomography (OCT) to observe microscopic changes in the eye in this condition. OCT can create 2-dimensional and 3-dimensional high definition images of the retina of the ONH and has been used to study various conditions such as glaucoma and multiple sclerosis. Numerous studies have used OCT in IIH as well, and they have shown that certain retinal layers and the ONH change in thickness and shape in both the short and long term with intracranial pressure changes. OCT is a promising modality for clinical and scientific evaluation of IIH as it is a noninvasive and practical tool to obtain in depth images. This review will discuss how OCT can be used to assess a patient with IIH, both before and after treatment, along with its limitations and future applications.

Evaluation of RETICs Glaucoma Diagnostic Calculators in Preperimetric Glaucoma

Purpose

To evaluate two glaucoma diagnostic calculators (GDC) in a group of eyes with preperimetric glaucoma (PPG).

Methods

All eyes (n = 265) included in this study had ocular hypertension with normal visual fields (VFs) on repeated VF tests. PPG was defined as progression in the Guided Progression Analysis software from Cirrus-optical coherence tomography (GPA-OCT). Three PPG types were defined according to the GPA-OCT software as follows: (1) GPA-OCT with one or more red boxes in two or more columns; (2) GPA-OCT with two or more red boxes in two or more columns; and (3) GPA-OCT with two or more red boxes in two or more columns (definition 2), and in the last scan one or more red box in the RNFL average or quadrants. Nonparametric tests, areas under the receiver operating characteristic curve (AUC), and Bland-Altman tests were assessed.

Results

Definitions one, two, and three were met by 44 (16.6%), 29 (10.9%), and 11 (4.2%) eyes, respectively. The GDC indices (means ± standard deviations) were, respectively, 14.49 ± 21.55% and 26.06 ± 22.50% using the combined and quantitative GDC (P < 0.001) in all eyes. Both GDC showed higher glaucoma probability in the PPG group (P < 0.04; combined GDC AUCs, 0.720–0.833; quantitative GDC AUCs, 0.700–0.839). GDC values were higher (P < 0.01) with greater GPA progression.

Conclusions

The values of both GDC were higher in the PPG group than the ocular hypertension group. The GDC were higher when more columns in the GPA software indicated progression. Both GDC showed a similar ability to detect PPG.

Translational Relevance

These calculators facilitate diagnosis of PPG in ocular hypertensive eyes.

Clinical Use of an Optical Coherence Tomography Linear Discriminant Function for Differentiating Glaucoma From Normal Eyes

PURPOSE

To determine and validate the diagnostic ability of a linear discriminant function (LDF) based on retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) thickness obtained using high-definition optical coherence tomography (Cirrus HD-OCT) for discriminating between healthy controls and early glaucoma subjects.

METHODS

We prospectively selected 214 healthy controls and 152 glaucoma subjects (teaching set) and another independent sample of 86 healthy controls and 71 glaucoma subjects (validating set). Two scans, including 1 macular and 1 peripapillary RNFL scan, were obtained. After calculating the LDF in the teaching set using the binary logistic regression analysis, receiver operating characteristic curves were plotted and compared between the OCT-provided parameters and LDF in the validating set.

RESULTS

The proposed LDF was 16.529-(0.132×superior RNFL)-(0.064×inferior RNFL)+(0.039×12 o'clock RNFL)+(0.038×1 o'clock RNFL)+(0.084×superior GCIPL)-(0.144×minimum GCIPL). The highest area under the receiver operating characteristic (AUROC) curve was obtained for LDF in both sets (AUROC=0.95 and 0.96). In the validating set, the LDF showed significantly higher AUROC than the best RNFL (inferior RNFL=0.91) and GCIPL parameter (minimum GCIPL=0.88). The LDF yielded a sensitivity of 93.0% at a fixed specificity of 85.0%.

CONCLUSIONS

The LDF showed better diagnostic ability for differentiating between healthy and early glaucoma subjects than individual OCT parameters. A classification algorithm based on the LDF can be used in the OCT analysis for glaucoma diagnosis.

Correlation between retinal nerve fiber layer and disc parameters in glaucoma suspected eyes

GOAL

The aim of the study was to estimate the diagnostic accuracy of optical coherence tomography parameters in normal, preperimetric, developed perimetric and terminal glaucoma.

METHODS

180 eyes of 140 consecutive patients were evaluated in this retrospective cross sectional pilot study. Copernicus Spectra--domain optical coherence tomography with resolution of 3 mm obtained through the optic nerve head were included. All examined eyes were divided into four groups (healthy eyes, initial, preperimetric glaucoma, developed perimetric glaucoma and terminal glaucoma).

RESULTS

The highest value of the RIM is noticed in control group 1.44 (1.21-1.70). There is no significant difference in the size of the disc in the eyes with developed open angle glaucoma (1.80 +/- 0.66) compared to normal eyes (p = 0.663), to the eyes with initial glaucoma (p = 0.120), and terminal glaucomatous atrophy (p = 0.068). There is statistically importance of E/D parameter in healthy group 0.17 (0.04-0.27), early glaucomatous group 0.44 (0.35-0.51), developed glaucoma 0.47 (0.39-0.61) respectively p < 0.005. The volume of cup was significantly greater in the eyes with terminal glaucomatous atrophy 1.05 (0.85-1.4) compared to the healthy eyes 0.31 (0.06-0.51) (p < 0.005), significantly greater to initial glaucoma 0.84 (0.58-1.12) (p = 0.007) and significantly higher compared to developed glaucoma 0.82 (0.62-1.07) (p = 0.003). There is no significant difference in the cup between the eyes with early and developed glaucoma (p = 0.912). The eyes with terminal glaucoma had significant lower value of the thickness of retinal nerve fiber layer 56.50 (45.50-71.25) compared to developed glaucoma group 82.5 (72-95.75), initial glaucoma 110.50 (102-123) and healthy eyes 132 (119-150) (p < 0.005).

CONCLUSION

The SD-OCT scanning should be used to quantify optic nerve head anatomy in human eyes. The changes can be recognized and can indicate as important risk factor in considering glaucoma changes. It also should be considered as an exact model of glaucoma pathology.

Evaluation of Central Macular Thickness and Retinal Nerve Fiber Layer Thickness using Spectral Domain Optical Coherence Tomography in a Tertiary Care Hospital

Purpose: To evaluate the normative data of macular thickness and retinal nerve fiber layer thickness (RNFL) among normal subjects using spectral domain optical coherence tomography (OCT).

Materials and methods: Normal subjects presenting to a tertiary medical hospital were included in the study. All patient underwent clinical examination followed by study of macular thickness and RN FL thick ness by spectral domain Topc on OCT. The data was collected and analyzed for variations in gender and age. The data was also compared with available literature.

Results: Total numbers of patients enrolled in the study were 154 (308 eyes). Numbers of males were 79 (158 eyes) and numbers of females were 75 (150 eyes). The mean age among males was 42.67 ± 12.15 years and mean age among females was 42.88 ± 11.73 years.

Overall the mean mac ular thickness (central 1 mm zone) with SD - OCT was 241.75 ± 17.3 microns. The mean macular volume was 7.6 cu. mm ± 0.33. On analysis of the RNFL thickness, we observed that the RNFL was thickest in the inferior quadrant (138.58) followed by superior (122.30) nasal (116.32) and temporal quadrant (73.04).

Gender-wise comparison of the data revealed no statistically significant difference for age, macular thickness parameters, volume and RFNL values except outer temporal thickness among males and females. No age-related difference was noted in the above parameters. On comparison with available norma tive data from India and elsewhere, we found significant variations with different machines.

Conclusion: The study is the first to provide normative data using SD-OCT from central India. The data from spectral domain OCT correlated well with the values obtained from similar studies with SD - OCT. Values obtained from time domain OCT machines are different and are not comparable.

How to cite this article: Agarwal P, Saini VK, Gupta S, Sharma A. Evaluation of Central Macular Thickness and Retinal Nerve Fiber Layer Thickness using Spectral Domain Optical

Coherence Tomography in a Tertiary Care Hospital. J Curr Glaucoma Pract 2014;8(2):75-81.

Association between ganglion cell complex and axial length

PURPOSE

We evaluated the association between each layer of macular ganglion cell complex (mGCC) and axial length measured with spectral-domain optical coherence tomography (OCT).

METHODS

One hundred and one eyes of 101 healthy younger women were assessed in this prospective study. In one eye, mGCC was measured two times with 3D-OCT 2000 (Topcon). The associations between mGCC and axial length were analyzed using single regression analysis. To support the data of this study, repeatability also was assessed by intraclass correlation coefficient (ICC), coefficient of variance (CoV), and test-retest standard deviation (TRTSD).

RESULTS

In each layer of the mGCC, ICC ranged from 0.980 to 0.997; CoV ranged from 0.8 to 2.4 %; TRTSD ranged from 0.8 to 3.0 μm. For every 1 mm of greater axial length, total macular retinal nerve fiber layer (mRNFL) thickness increased by 1.1 μm (p < 0.01), and total macular ganglion cell layer and inner plexiform layer (mGCL+) and mGCC thickness decreased by 2.5 μm (p < 0.001) and 1.4 μm (p = 0.018), respectively.

CONCLUSIONS

In healthy younger participants, mGCC measurement using 3D OCT-2000 showed good repeatability. As axial length increased, total mGCC decreased, whereas total mRNFL and mGCL+ showed an inverse correlation.