Comparative studies of RNFL thickness measured by OCT with global index of visual fields in patients with ocular hypertension and early open angle glaucoma

Factors Associated with 5-year Glaucomatous Progression in Glaucoma Suspect Eyes: A Retrospective Longitudinal Study

Purpose

Using demographic, clinical, visual field, and optical coherence tomography (OCT) variables to study the association of 5-year glaucomatous progression in glaucoma suspect eyes.

Patients and methods

This is a retrospective longitudinal clinical study. Inclusion criteria consisted of glaucoma suspect eyes (i.e., concerning cup-to-disk ratio and/or intraocular pressure (IOP) >21 mm Hg), age ≥ 30 years old, follow-up time of 5 years, best-corrected visual acuity (BCVA) of 20/100 or better, spherical equivalent (SE) higher than 8 diopters and an astigmatism less than 3 diopters. Eyes with glaucoma—determined by two consecutive, reliable visual field tests—were excluded, as well as any eyes with any clinically significant retinal or neurological disease. The percentage of glaucoma suspect eyes, which progressed to glaucoma within a 5-year period, was calculated. Study subjects were divided into the following groups: eyes that progressed to glaucoma and those that did not.

Results

In the 288 patients which we looked at, 365 total eyes, 323 eyes had concerning cup-to-disk ratio and 42 had ocular hypertension. Bivariate analysis showed that the eyes which progressed to glaucoma had significantly worse mean deviation, increased pattern standard deviation (PSD), and less visual field index (VFI). Our bivariate analysis also showed a thinner average, superior and inferior retinal nerve fiber layer thickness (RNFL), and more severe average, superior, and inferior RNFL damages (i.e., color grading scale) at baseline. Logistic regression analysis showed that only PSD and severe inferior RNFL damage (i.e., red color) to be significantly associated with 5-year glaucomatous progression.

Conclusion

Segmental RNFL damage and pattern standard deviation are associated with 5-year glaucomatous progression in glaucoma suspect eyes.

How to cite this article

Nassiri N, Das S, Patel V, et al. Factors Associated with 5-year Glaucomatous Progression in Glaucoma Suspect Eyes: A Retrospective Longitudinal Study. J Curr Glaucoma Pract 2022;16(1):11-16.

Correlation of retinal nerve fiber layer thickness with perimetric staging in primary open-angle glaucoma - A cross-sectional study

BACKGROUND

Glaucoma is a progressive optic neuropathy, characterized by structural optic nerve damage with corresponding field defects. Primary open-angle glaucoma (POAG) is the most common. Although perimetry is the gold standard, retinal nerve fiber layer (RNFL) thickness by spectral-domain optical coherence tomography (SD-OCT) has proved reliable in the detection of pre-perimetric glaucoma. There is preferential involvement of various sectors of the peripapillary RNFL in the different stages of POAG.

PURPOSE

The purpose of this study is to assess RNFL thickness and determine preferential involvement of different sectors of peripapillary RNFL in the various stages of POAG using SD-OCT.

MATERIALS AND METHODS

Forty-nine patients with POAG underwent complete ophthalmic examination including visual field testing and RNFL thickness measurement. Perimetric findings were used to categorize them into mild, moderate, and severe stages of glaucoma. The RNFL thickness values were analyzed and compared with perimetric results.

RESULTS

The average RNFL loss in mild, moderate, and severe POAG was 25.44%, 29.67%, and 44.15%, respectively. A statistically significant correlation (P < 0.05) between RNFL loss and severity of glaucoma was found in all except the superior and temporal sectors. A statistically significant (P < 0.05) negative correlation was noted between visual field index and RNFL loss in all sectors except the nasal-superior in moderate POAG and all sectors in severe POAG. Mean deviation and RNFL loss showed a significant positive correlation in temporal-inferior (TI) sector in mild POAG and all sectors in the severe group.

CONCLUSION

RNFL thickness decreases with increase in glaucoma severity and is a reliable parameter to differentiate mild from severe POAG. The TI followed by nasal-inferior RNFL sector is the most sensitive to glaucomatous damage in all three stages.

Is retinal nerve fibre layer thickness correlated with visual function in individuals having optic neuritis?

CLINICAL RELEVANCE

The existence of a correlation between the results of paraclinical retinal imaging and clinical tests such as contrast sensitivity can reduce time and cost in diagnosing optic neuritis (ON).

BACKGROUND

To demonstrate whether changes of peripapillary retinal nerve fibre layer (RNFL) thickness are correlated with the results of visual acuity, contrast sensitivity and colour vision in eyes with acute ON.

METHODS

Thirty patients with acute ON, 23 females and seven males, who had no previous history of ON in neither eye, were examined. Inclusion criteria were: subjects had spherical refraction of less than ±5D, no prior ON or optic disc swelling, no history of amblyopia or colour blindness, and no history or ophthalmoscopic evidence of glaucoma, diabetic retinopathy, or maculopathies. Visual acuity, contrast sensitivity and colour vision were tested and optical coherence tomography was performed for all patients after complete ophthalmologic examinations including refraction, biomicroscopy, and funduscopy with a 90D lens by a neuro-ophthalmologist.

RESULTS

Thirty patients who were 18-45 years old entered the study. There was an inverse correlation between contrast sensitivity and nasal (r = -0.430, p = 0.018), inferior (r = -0.503, p = 0.005) and mean (r = -0.510, p = 0.004) RNFL thickness. The multiple linear regression model, after adjustment for age and sex, showed a significant association between visual acuity and nasal RNFL thickness (coefficient = 0.025, p = 0.032). There was also a significant inverse correlation between contrast sensitivity and nasal (coefficient = -0.003, p = 0.036), inferior (coefficient = -0.006, p = 0.010) and mean (coefficient = -0.007, p = 0.012) RNFL thickness. No significant correlation was found between colour vision and RNFL thickness.

CONCLUSION

Contrast sensitivity is more correlated with changes in RNFL thickness in comparison with visual acuity and colour vision. Contrast sensitivity measurement therefore can be used as one of the first assessments in patients with ON.

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

Quantitative assessment of secondary white matter injury in the visual pathway by pituitary adenomas: a multimodal study at 7-Tesla MRI

OBJECTIVE

The objective of this study was to investigate microstructural damage caused by pituitary macroadenomas by performing probabilistic tractography of the optic tracts and radiations using 7-T diffusion-weighted MRI (DWI). These imaging findings were correlated with neuro-ophthalmological results to assess the utility of ultra-high-field MRI for objective evaluation of damage to the anterior and posterior visual pathways.

METHODS

Probabilistic tractography employing 7-T DWI was used to reconstruct the optic tracts and radiations in 18 patients with adenomas and in 16 healthy volunteers. Optic chiasm compression was found in 66.7% of the patients and visual defects in 61.1%. Diffusion indices were calculated along the projections and correlated with tumor volumes and results from neuro-ophthalmological examinations. Primary visual cortical thicknesses were also assessed.

RESULTS

Fractional anisotropy was reduced by 21.9% in the optic tracts (p < 0.001) and 17.7% in the optic radiations (p < 0.001) in patients with adenomas. Patients showed an 8.5% increase in mean diffusivity of optic radiations compared with healthy controls (p < 0.001). Primary visual cortical thickness was reduced in adenoma patients. Diffusion indices of the visual pathway showed significant correlations with neuro-ophthalmological examination findings.

CONCLUSIONS

Imaging-based quantification of secondary neuronal damage from adenomas strongly correlated with neuro-ophthalmological findings. Diffusion characteristics enabled by ultra-high-field DWI may allow preoperative characterization of visual pathway damage in patients with chiasmatic compression and may inform prognosis for vision recoverability.

Optical coherence tomography findings in chronic progressive external ophthalmoplegia

BACKGROUND

Chronic progressive external ophthalmoplegia (CPEO) is a mitochondrial encephalomyopathy caused by multiple mtDNA abnormalities. There is little information about the changes of ocular fundus with CPEO. The aim of this work was to measure and evaluate changes in the macular retinal thickness and optic nerve head in patients with CPEO using spectral-domain optical coherence tomography and to compare the findings with those of healthy individuals.

METHODS

Totally, 18 CPEO patients were enrolled in this study. Healthy volunteers matched for gender, age, and diopter settings were included as a control group. The retinal thickness of macular central fovea, inner and outer retinal layer thickness of perifoveal macular, optic nerve head parameters, and peripapillay retinal nerve fiber layer thickness (pRNFLT) for all included cases were measured using spectral-domain optical coherence tomography. A paired t test was used to compare the differences in the studied parameters between the two groups. The correlations between macular retinal thickness, pRNFLT, disease duration, and age of onset were also analyzed.

RESULTS

Among the macular parameters, retinal thickness of macular central fovea (t = -2.135, P < 0.05) and outer retinal layer thickness (t = -1.994, P < 0.05) of patients in the CPEO group were statistically significant lower than those of patients in the normal control group. For the optic nerve head parameters, the patients in the CPEO group showed a larger rim volume (t = -2.499, P < 0.05) and nerve head volume (t = -2.103, P < 0.05). The overall pRNFLT of patients in the CPEO group was statistically significant lower than that of patients in the control group (t = -4.125, P < 0.05). The comparison of pRNFLT in eight sectors showed that the pRNFLT of patients in the CPEO group was statistically significant lower than that of the control group mainly in the inferior and temporal sectors. The degree of pRNFL defect negatively correlated with the disease duration (r = -0.583, P < 0.05).

CONCLUSIONS

The retinal thickness of patients with CPEO was significantly thinner, which was mostly the outer retina. The patients' optic discs had a low volume and the loss of the retinal nerve fiber layer was obvious. With the extension of the disease duration, the retinal nerve fiber layer defect was even more significant.

The Relation of White-on-White Standard Automated Perimetry, Short Wavelength Perimetry, and Optic Coherence Tomography Parameters in Ocular Hypertension

PURPOSE

The purpose of this study is to examine the demographics, clinical properties, and the relation between white-on-white standard automated perimetry (SAP), short wavelength automated perimetry (SWAP), and optical coherence tomographic (OCT) parameters of patients with ocular hypertension.

MATERIALS AND METHODS

Sixty-one eyes of 61 patients diagnosed with ocular hypertension in the Ankara Numune Education and Research Hospital ophthalmology unit between January 2010 and January 2011 were included in this study. All patients underwent SAP and SWAP tests with the Humphrey visual field analyser using the 30.2 full-threshold test. Retinal nerve fiber layers (RNFL) and optic nerve heads of patients were evaluated with Stratus OCT.

RESULTS

Positive correlation was detected between SAP pattern standard deviation value and average intraocular pressure (P=0.017), maximum intraocular pressure (P=0.009), and vertical cup to disc (C/D) ratio (P=0.009). Positive correlation between SWAP median deviation value with inferior (P=0.032), nasal (P=0.005), 6 o'clock quadrant RNFL thickness (P=0.028), and Imax/Tavg ratio (P=0.023) and negative correlation with Smax/Navg ratio (P=0.005) were detected. There was no correlation between central corneal thickness and peripapillary RNFL thicknesses (P>0.05).

CONCLUSIONS

There was no relation between SAP median deviation, pattern standard deviation values and RNFL thicknesses and optic disc parameters of the OCT. By contrast significant correlation between several SWAP parameters and OCT parameters were detected. SWAP appeared to outperform achromatic SAP when the same 30-2 method was used.

Comparison of Pattern Electroretinography and Optical Coherence Tomography Parameters in Patients with Primary Open-Angle Glaucoma and Ocular Hypertension

Objectives:

To investigate the correlation of visual field (VF), pattern electroretinography (PERG) and Fourier domain optical coherence tomography (FD-OCT) results in patients with ocular hypertension (OHT) and early primary open-angle glaucoma (POAG).

Materials and Methods:

The study included 72 eyes of 37 patients with early POAG, 76 eyes of 38 patients with OHT, and 60 eyes of 30 controls. All subjects underwent full ophthalmologic examination, VF assessment with 24-2 Humphrey standard automated perimetry (Swedish Interactive Thresholding Algorithm (SITA)-Standard), retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thickness measurement with FD-OCT, and PERG P50 and N95 wave latency and amplitude measurements with electroretinography (Nihon Kohden).

Results:

With the exception of the nasal quadrant, all GCC parameters and RNFL results were significantly lower in the POAG group compared to the OHT and control groups. There was no statistically significant difference between the OHT and control group. PERG amplitudes were lower in the POAG and OHT groups than in the control group. Reduction in N95 amplitude was greater than that of P50 amplitude. No difference was detected in PERG latencies among groups. GCC was significantly correlated with VF and RNFL in the POAG group.

Conclusion:

Significant thinning of the GCC and RNFL occurs in addition to VF pathologies in patients with early POAG, and these examinations should be concomitantly evaluated. During diagnostic assessment of patients with early POAG, GCC and RNFL analysis by FD-OCT are highly effective. GCC is as reliable as RNLF in the early diagnosis of glaucoma and there is a highly significant correlation between them. Dysfunction of ganglion cells in patients with OHT may be detected earlier using PERG amplitude analysis.

Electrophysiology and colour: a comparison of methods to evaluate inner retinal function

PURPOSE

Several methods are routinely used in the clinic to diagnose and monitor diseases of inner retinal function. In this study, we compare four such methods in patients with diabetes and glaucoma, to determine correlations between their results and to determine which method is most sensitive for detecting disease.

METHODS

Twenty control subjects, 12 patients with early glaucoma and eight patients with diabetes mellitus, were enrolled in the study. All underwent four examinations: transient pattern electroretinogram (PERG), multifocal pattern electroretinogram (mfPERG), chromatic contrast threshold measurements (protan and tritan), and blue-on-yellow short-wavelength automated perimetry (SWAP).

RESULTS

For the total cohort of 40 subjects, the results show a significant correlation between the amplitudes of the PERG and those of the mfPERG, as well as between the tritan contrast thresholds and the SWAP MD. Furthermore, ROC analyses reveal that colour contrast thresholds could significantly distinguish between the patient and the control group. Glaucoma patients alone could also be distinguished.

CONCLUSIONS

We conclude that the methods compared in this study show correlations between their results if they are testing same pathway or underling cells, and that the colour contrast threshold is the most sensitive method to detect early functional deficits in diabetic and glaucoma patients.

Quantitative analysis of localized retinal nerve fiber layer defects using spectral domain optical coherence tomography

PURPOSE

To compare the topographic features of localized retinal nerve fiber layer (RNFL) defects presented in red-free RNFL photography and spectral domain optical coherence tomography (SD-OCT), and to evaluate the correlation with structural and functional parameters.

METHODS

Sixty eyes with localized RNFL defects in red-free RNFL photographs were included. RNFL thickness map and significance map were obtained by SD-OCT. The angular location, angular width, and area of localized RNFL defects were measured and compared among RNFL thickness map, significance map (red, <1% level; yellow, <5% level), and RNFL photograph. The RNFL defect areas were analyzed by their correlations with structural and functional parameters.

RESULTS

The RNFL defect area of RNFL thickness map was significantly greater than those of red significance map, and smaller than those of RNFL photograph and yellow significance map (all P<0.001). RNFL thickness map showed a significantly narrower angular width than RNFL photograph and yellow significance map (all P<0.001). The area, angular width, and angular location of localized RNFL defects in RNFL photographs strongly correlated with those of RNFL thickness maps and significance maps (all r≥0.741, P<0.001). The relationship between RNFL defect area and structural-functional parameters was also significant.

CONCLUSIONS

The high topographic correlations in RNFL defects between RNFL photography and SD-OCT RNFL maps suggest the validity of SD-OCT RNFL imaging for detecting localized glaucomatous RNFL damage. In addition, structural and functional parameters are closely related to RNFL defect areas. Quantitative measurements of RNFL defects might be valuable for glaucoma diagnosis.

The Relationship between Visual Field Global Indices and Retinal Nerve Fiber Layer Thickness in Healthy Myopes

The aim of the current study was to investigate the association between the thickness of the retinal nerve fiber layer (RNFL) and central visual field indices in otherwise healthy myopes. In total, 57 otherwise healthy subjects were cross-sectionally studied. General ophthalmic examinations, refractive measurements, RNFL thickness by spectral domain optical coherence tomography (OCT), and central visual fields were examined. Linear models were used to assess the associations. In this young and mid-aged population, the mean spherical equivalent was −4.79 (SD 1.66) and −4.59 (SD 1.88) diopters in the right and left eyes, respectively. Approximately 7% to 14% of the eyes showed the average RNFL thickness out of the normal range. The temporal RNFL was remarkably thicker, whereas the nasal RNFL was thinner. The higher the refractive error, the thinner the RNFL thickness. A thicker overall RNFL was significantly associated with decreased mean sensitivity and increased mean defect, and further adjustments for age, sex, refractive error, optic disk area, or ocular magnification did not change the association. Although nonpathologic myopia does not significantly affect central visual field global indices, its effects on the RNFL may be linked with performance on the central visual field test.

Cellular responses following retinal injuries and therapeutic approaches for neurodegenerative diseases

Retinal neurodegenerative diseases like age-related macular degeneration, glaucoma, diabetic retinopathy and retinitis pigmentosa each have a different etiology and pathogenesis. However, at the cellular and molecular level, the response to retinal injury is similar in all of them, and results in morphological and functional impairment of retinal cells. This retinal degeneration may be triggered by gene defects, increased intraocular pressure, high levels of blood glucose, other types of stress or aging, but they all frequently induce a set of cell signals that lead to well-established and similar morphological and functional changes, including controlled cell death and retinal remodeling. Interestingly, an inflammatory response, oxidative stress and activation of apoptotic pathways are common features in all these diseases. Furthermore, it is important to note the relevant role of glial cells, including astrocytes, Müller cells and microglia, because their response to injury is decisive for maintaining the health of the retina or its degeneration. Several therapeutic approaches have been developed to preserve retinal function or restore eyesight in pathological conditions. In this context, neuroprotective compounds, gene therapy, cell transplantation or artificial devices should be applied at the appropriate stage of retinal degeneration to obtain successful results. This review provides an overview of the common and distinctive features of retinal neurodegenerative diseases, including the molecular, anatomical and functional changes caused by the cellular response to damage, in order to establish appropriate treatments for these pathologies.

Speckle reduction of retinal optical coherence tomography based on contourlet shrinkage

Speckle reduction of retinal optical coherence tomography (OCT) images helps the diagnosis of ocular diseases. In this Letter, we present a speckle reduction method based on shrinkage in the contourlet domain for retinal OCT images. The algorithm overcomes the disadvantages of the wavelet shrinkage method, which lacks directionality and anisotropy. The trade-off between speckle reduction and edge preservation is controlled by a single adjustable parameter, which determines the threshold in the contourlet domain. Results show substantial reduction of speckle noise and enhanced visualization of layer structures as demonstrated in the image of the central fovea region of the human retina. It is expected to be utilized in a wide range of biomedical imaging applications.

Quantitative 3-T diffusion tensor imaging in detecting optic nerve degeneration in patients with glaucoma: association with retinal nerve fiber layer thickness and clinical severity

INTRODUCTION

To investigate the association of quantitative 3-T diffusion tensor imaging (DTI) with retinal nerve fiber layer (RNFL) thickness measured by optical coherence tomography (OCT) and clinical severity in detecting optic nerve degeneration in patients with primary closed-angle glaucoma.

METHODS

Twenty three patients (42 eyes; 9 men, 14 women) with primary closed-angle glaucoma and 20 healthy controls were enrolled in this study. Both DTI and OCT were performed on the optic nerves of all subjects. The mean diffusivity (MD), fractional anisotropy (FA), and eigenvalue maps were obtained for quantitative analysis. RNFL thickness and quantitative electrophysiology were also performed on all subjects. The association of quantitative DTI with RNFL thickness and glaucoma stage was analyzed.

RESULTS

Compared with control nerves, the FA, λ[parallel], and λ[perpendicular] values, and RNFL thickness in affected nerves decreased, while MD increased in patients with primary glaucoma (p < 0.05). There was a significant correlation between FA, MD, λ[parallel], and λ[perpendicular] and the mean RNFL thickness (P < 0.01). The mean FA and λ[perpendicular] values derived with DT MR imaging correlated well with glaucoma stage (P < 0.05), but the mean MD and λ[parallel] values did not correlate with glaucoma stage (P > 0.05).

CONCLUSION

DTI measurement could detect abnormality of the optic nerve in patients with glaucoma and may serve as a biomarker of disease severity.

Intra-retinal layer segmentation in optical coherence tomography images

Retinal layer thickness, evaluated as a function of spatial position from optical coherence tomography (OCT) images is an important diagnostics marker for many retinal diseases. However, due to factors such as speckle noise, low image contrast, irregularly shaped morphological features such as retinal detachments, macular holes, and drusen, accurate segmentation of individual retinal layers is difficult. To address this issue, a computer method for retinal layer segmentation from OCT images is presented. An efficient two-step kernel-based optimization scheme is employed to first identify the approximate locations of the individual layers, which are then refined to obtain accurate segmentation results for the individual layers. The performance of the algorithm was tested on a set of retinal images acquired in-vivo from healthy and diseased rodent models with a high speed, high resolution OCT system. Experimental results show that the proposed approach provides accurate segmentation for OCT images affected by speckle noise, even in sub-optimal conditions of low image contrast and presence of irregularly shaped structural features in the OCT images.