Early Normal Tension Glaucoma Research Articles

Systemic Arterial Stiffness and Choroidal Microvascular Insufficiency on the Structural Progression of Normal Tension Glaucoma

PurposeTo identify the role of systemic arterial stiffness and choroidal microvascular insufficiency on structural progression of normal-tension glaucoma (NTG). DesignRetrospective cohort study. MethodsA total of 107 early NTG eyes of 88 patients, who underwent pulse wave velocity (PWV) measurements and optical coherence tomography (OCT) angiography (OCT-A) at baseline, were categorized depending on the presence of peripapillary choroidal microvasculature dropout (MvD) and PWV. Differences in glaucomatous progression were analyzed. Structural progression rates were determined using the trend-based analysis of cirrus OCT. ResultsThirty-two eyes displayed choroidal MvD (62.7 (95% CI 58.4-67.0) years old, 53.6% males), and 70 eyes did not show any MvD (59.9 (95% CI 57.1-62.6) years old, 53.3% males) at baseline. Patients were followed for 48.4 (95% CI 40.0-56.8) months. When they were further divided based on PWV (high PWV≥1400cm/sec), those with choroidal MvD and high PWV showed significantly faster thinning in macular ganglion cell-inner plexiform layer (GCIPL; P=0.023). In comparison to those with low PWV and no MvD, eyes with high PWV and MvD in the peripapillary area were likely to show fast structural progression (≤-1.2 µm/year) in the macular GCIPL by odds of 6.019 (95% CI 1.619-38.531, P=0.025). ConclusionsIn NTG eyes, GCIPL thinning was faster when choroidal MvD and high systemic arterial stiffness were present. The simultaneous presence of regional and systemic vascular insufficiency may be associated with rapid glaucoma structural progression in eyes with low baseline intraocular pressure.

Rim Area to Disc Area Ratio in Early Normal Tension Glaucoma

Rim Area to Disc Area Ratio in Early Normal Tension Glaucoma

The Differences in the Pattern of OCT and OCTA Examinations between Early Normal- and High-Tension Pseudoexfoliative Glaucoma.

Purpose. The aim of this study was to compare the results of optical coherence tomography angiography (OCTA) and optical coherence tomography (OCT) examinations in patients with normal-tension glaucoma (NTG) in comparison to high-tension pseudoexfoliative glaucoma (HTG) patients at the early stage of glaucoma. Material and methods. The studied groups consisted of patients in the early stage of NTG (70 eyes) and the early stage of HTG (71 eyes). In NTG and HTG groups, a detailed ophthalmic examination was performed. Optic disc OCT with peripapillary RNFL measurements and OCTA examination with the evaluation of the macula and optic disc were performed for all participants using Zeiss Cirrus 5000. Results. NTG and HTG groups were statistically similar as far as the MD was concerned, and both groups had early glaucoma. When evaluating the RNFL thickness, the only statistical difference between early NTG and HTG was observed in the thicknesses in the temporal sector of peripapillary RNFL, with thinner values in the NTG group (53.94 vs. 59.94, p = 0.0071). When the OCTA results of the macula and optic disc were evaluated, there were no statistical differences between early NTG and HTG. Conclusions. The vascular density and flow parameters assessed in OCTA were equal between early NTG and HTG, and therefore the involvement of vascular factors in NTG pathogenesis could not be confirmed. Our results confirm the preponderance of more frequent temporal RNFL involvement in early NTG.

Topographic Differences in Superficial Macular Vessel Density in Eyes with Early Primary Open-Angle Glaucoma and Normal Tension Glaucoma

Introduction: The aim of the study was to compare macular vascular microcirculation in early primary open-angle glaucoma (POAG), normal tension glaucoma (NTG), and normal subjects. Methods: 99 patients with early glaucoma (99 eyes: 60 POAG and 39 NTG) and 78 normal subjects were included. All subjects underwent optical coherence tomography angiography scan at 6 × 6 mm macular area. Macular vessel density (VD) and perfusion density (PD) and 9 sectors were compared between the controls, POAG, and NTG groups. Linear regression analysis was used to investigate the relationship between VD and other variables including macular PD, signal strength (SS), and mean macular ganglion cell-inner plexiform layer (mGCIPL) thickness. Results: Significant losses in total area of VD and PD were detected in POAG and NTG groups compared to the controls (all p < 0.01). There were no significant differences in all inner sectors of macular VD and PD between POAG and controls (all p > 0.05). Except for outer-nasal sector, all other outer sectors of macular VD and PD were significantly lower in POAG than in the controls (all p < 0.01). The inferior-inner sector and all outer sectors of VD and PD were significantly lower in NTG than in the controls (all p < 0.01). Macular VD was significantly correlated with macular PD (r = 0.99, p < 0.001), SS (r = 0.60, p < 0.001), and mGCIPL thickness (r = 0.51, p < 0.001). Conclusions: Macular microcirculation declined significantly in early POAG and NTG patients. Macular microcirculation loss in the NTG group was more central and nasal compared with that in the POAG group. A decrease in macular VD was correlated with lower macular PD, lower SS, and thinner mGCIPL thickness.

Early Detection of Primary Open Angle, Angle Closure, and Normal Tension Glaucoma in an Asian Population Using Optical Coherence Tomography.

Spectral-domain optical coherence tomography (SD-OCT) facilitates early glaucoma detection in the Chinese population in Taiwan. The best parameters for primary open angle glaucoma (POAG), primary angle closure glaucoma (PACG), normal tension glaucoma (NTG), and suspected glaucoma (GS) detection are temporal inferior Bruch's membrane opening-minimum rim width (BMO-MRW), inner temporal macular ganglion cell layer (mGCL), temporal superior Circumpapillary retinal nerve fiber layer (cpRNFL), and mean global BMO-MRW, respectively. We investigated the diagnostic capability of SD-OCT for different types of early glaucoma among the Chinese population in Taiwan. One eye each was assessed from 113 individuals with healthy eyes, 125 individuals with suspected glaucoma (GS), and 156 patients with early glaucoma (POAG, 87; PACG, 50; and NTG, 19). Circumpapillary (cp) RNFL thickness (global and sectoral), BMO-MRW, and macular parameters, including the macular RNFL (mRNFL), mGCL, and macular inner plexiform layer (mIPL), were assessed using SD-OCT. The areas under receiver operator characteristic curves (AUCs) were calculated to evaluate the diagnostic capacity of the parameters to differentiate between healthy and early glaucomatous eyes. The parameters most suitable for detecting early POAG, PACG, NTG, and GS were temporal inferior BMO-MRW (AUC, 0.847), inner temporal mGCL (AUC, 0.770), temporal superior cpRNFL (AUC, 0.861), and mean global BMO-MRW (AUC, 0.768), respectively. Among the macular parameters, the mGCL exhibited the highest diagnostic capacity. The diagnostic capacity of the mGCL was lower than that of cpRNFL and BMO-MRW for POAG and NTG but not PACG. After adjusting for confounding variables in multivariable analysis, the AUC was determined to be 0.935 for POAG and 0.787 for GS. SD-OCT facilitates the detection of early POAG, PACG, and NTG. Using a combination of cpRNFL, BMO-MRW, and macular parameters may enhance their diagnostic capacities. Further studies are necessary to validate these findings.

Deep learning classification of early normal-tension glaucoma and glaucoma suspect eyes using Bruch's membrane opening-based disc photography.

We aimed to investigate the performance of a deep learning model to discriminate early normal-tension glaucoma (NTG) from glaucoma suspect (GS) eyes using Bruch's membrane opening (BMO)-based optic disc photography. 501 subjects in total were included in this cross-sectional study, including 255 GS eyes and 246 eyes of early NTG patients. BMO-based optic disc photography (BMO overview) was obtained from spectral-domain optical coherence tomography (OCT). The convolutional neural networks (CNN) model built from scratch was used to classify between early NTG and GS. For diagnostic performances of the model, the accuracy and the area under the curve (AUC) of the receiver operating characteristic curve (ROC) were evaluated in the test set. The baseline demographics were age, 48.01 ± 13.03 years in GS, 54.48 ± 11.28 years in NTG (p = 0.000); mean deviation, -0.73 ± 2.10 dB in GS, -2.80 ± 2.40 dB in NTG (p = 0.000); and intraocular pressure, 14.92 ± 2.62 mmHg in GS, 14.79 ± 2.61 mmHg in NTG (p = 0.624). Our CNN model showed the mean AUC of 0.94 (0.83-1.00) and the mean accuracy of 0.91 (0.82-0.98) with 10-fold cross validation for discriminating between early NTG and GS. The performance of the CNN model using BMO-based optic disc photography was considerably good in classifying early NTG from GS. This new disc photography of BMO overview can aid in the diagnosis of early glaucoma.

Visual Tract Degradation in Bilateral Normal-Tension Glaucoma-Cortical Thickness Maps and Volumetric Study of Visual Pathway Areas.

The aim of the study was to evaluate changes in the central visual pathways during the early and advanced stages of bilateral normal-tension glaucoma (NTG). Methods: The studied groups constituted patients with bilateral normal-tension glaucoma of the same stage (n = 45) and age-matched healthy volunteers (n = 17). All patients underwent ophthalmic examination and examination on a 1.5 Tesla Magnetic Resonance Scanner (Optima 360, GE Healthcare). Volume and cortical thickness analyses were performed using the open-source automated software package FreeSurfer. Results: There was a significant difference in lateral geniculate nuclei volume between the control and advanced glaucoma groups in the right hemisphere (p = 0.03) and in the left hemisphere between the early and advanced glaucoma patients (p = 0.026). The optic chiasm volume differed significantly between the control and advanced NTG groups (p = 0.0003) and between early and advanced glaucoma patients (p = 0.004). Mean cortical thickness analysis revealed a significant increase in values in the advanced glaucoma group in the right Brodmann area 17 (BA17) (p = 0.007) and right BA18 (p = 0.049) as compared to early NTG. In the left BA18 area, the mean thickness of the cortex in the early glaucoma group was significantly lower than in the control group (p = 0.03). Conclusions: The increase in the grey matter thickness in the V1 region with more-advanced glaucoma stages may reflect compensatory hypertrophy. Additionally, the regions of the brain early affected during glaucoma with reduced thickness were the right lateral occipital gyrus and left lingual gyrus. The most prominent change during the course of glaucoma was the increase in grey matter thickness in the right cuneus.

Relationship between macular intercapillary area measured by optical coherence tomography angiography and central visual field sensitivity in normal tension glaucoma

PurposeTo investigate the relationship of macular intercapillary area (ICA) with macular ganglion cell-inner plexiform layer (GCIPL) thickness and central visual field sensitivity (CVFS) in normal tension glaucoma (NTG).MethodsSeventy-eight early NTG...

Comparison of optical coherence tomography angiography metrics in primary angle-closure glaucoma and normal-tension glaucoma

To investigate the peripapillary vascular metrics in early normal tension glaucoma (NTG) and early primary angle closure glaucoma (PACG) eyes using optical coherence tomography angiography (OCT-A). One or both eyes of each subject were imaged for a 3 × 3 mm peripapillary region by swept-source OCT-A (DRI-OCT Triton, Topcon, Japan) and assessed by an automated MATLAB program. OCT-A metrics including circumpapillary vessel density (cpVD) and fractal dimension (cpFD) were compared. Their association with visual field (VF) parameters and retinal nerve fiber layer (RNFL) thickness were determined. Sixty-eight eyes of 51 PACG, 68 eyes of 48 NTG, and 68 eyes of 49 control subjects were cross-sectionally analyzed. NTG eyes had significantly lower global cpVD (52.369 ± 0.781%) compared with PACG eyes (55.389 ± 0.721%, P = 0.004) that had comparable disease severity and average RNFL thickness. Multivariable analysis revealed that, for PACG and NTG eyes, decreased cpVD ([PACG] β = −4.242; CI: −8.120, −0.363 vs [NTG] β = −5.531; CI: −9.472, −1.590) and cpFD ([PACG] β = −8.894;CI: −11.925, −5.864 vs [NTG] β = −12.064; CI: −17.095, −6.932) were associated with decreased RNFL thickness (all P ≤ 0.032); with a stronger association between decrease cpFD and decreased RNFL thickness in NTG eyes (P = 0.028). Decreased cpVD was associated with decrease mean deviation (MD) in NTG eyes (β = −0.707; CI: −1.090, −0.324; P ≤ 0.001) and not associated with the visual field parameters in PACG eyes. Early NTG had lower global cpVD compared with early PACG, despite similar disease severity and average RNFL thickness.

Retinal Thickness Asymmetry in Highly Myopic Eyes with Early Stage of Normal-Tension Glaucoma.

Purpose To investigate the retinal thickness asymmetry parameters of circumpapillary retinal nerve fiber layer (cpRNFL) and macular layers measured by spectral-domain optical coherence tomography in highly myopic (HM) patients with an early stage of normal-tension glaucoma (NTG). Methods This cross-sectional study included 55 eyes of HM patients with early NTG and 37 eyes of HM normal participants. High myopia was defined as spherical equivalence more myopic than −6 diopters. Thickness differences and asymmetry indices (AIs) of cpRNFL between superior and inferior corresponding parts and thickness differences and AIs of the total macular layer (TML) and inner macular layers between superior and inferior hemispheres were calculated. The areas under the receiver operating characteristic curves (AROCs) were analyzed and compared. Results In the cpRNFL asymmetry analysis, the thickness differences and AIs of cpRNFL between temporal-superior and temporal-inferior sectors (P < 0.0001 and P < 0.0001, respectively) and between superior and inferior quadrants (P = 0.002 and P < 0.0001, respectively) were significantly different between HM control subjects and HM NTG patients. In the macular asymmetry analysis, the thickness difference and AI of TML were significantly different between superior and inferior hemispheres (P < 0.0001 and P < 0.0001, respectively). The thickness difference and AI of the macular ganglion cell layer (mGCL) were significantly different between superior and inferior hemispheres (P < 0.0001 and P < 0.0001, respectively). The AROCs for thickness difference of TML (0.845) and thickness difference of mGCL (0.773) were comparable to AROCs for average cpRNFL thickness (0.842), macular retinal nerve fiber layer thickness (mRNFL) thickness (0.871), and mGCL thickness (0.822). Conclusion In our study, HM NTG patients had retinal thickness asymmetry in cpRNFL, TML, and mGCL. The diagnostic capabilities for thickness asymmetry of TML and mGCL were comparable to the diagnostic capabilities for cpRNFL thickness, mRNFL thickness, and mGCL thickness. Asymmetry analysis of retinal thickness can be an adjunctive tool for the early detection of HM NTG.

Deep learning classification of early normal-tension glaucoma and glaucoma suspects using Bruch\u2019s membrane opening-minimum rim width and RNFL

We aimed to classify early normal-tension glaucoma (NTG) and glaucoma suspect (GS) using Bruch’s membrane opening-minimum rim width (BMO-MRW), peripapillary retinal nerve fiber layer (RNFL), and the color classification of RNFL based on a deep-learning model. Discriminating early-stage glaucoma and GS is challenging and a deep-learning model may be helpful to clinicians. NTG accounts for an average 77% of open-angle glaucoma in Asians. BMO-MRW is a new structural parameter that has advantages in assessing neuroretinal rim tissue more accurately than conventional parameters. A dataset consisted of 229 eyes out of 277 GS and 168 eyes of 285 patients with early NTG. A deep-learning algorithm was developed to discriminate between GS and early NTG using a training set, and its accuracy was validated in the testing dataset using the area under the curve (AUC) of the receiver operating characteristic curve (ROC). The deep neural network model (DNN) achieved highest diagnostic performance, with an AUC of 0.966 (95%confidence interval 0.929–1.000) in classifying either GS or early NTG, while AUCs of 0.927–0.947 were obtained by other machine-learning models. The performance of the DNN model considering all three OCT-based parameters was the highest (AUC 0.966) compared to the combinations of just two parameters. As a single parameter, BMO-MRW (0.959) performed better than RNFL alone (0.914).

Rate of Change in Bruch's Membrane Opening-Minimum Rim Width and Peripapillary RNFL in Early Normal Tension Glaucoma.

Background: to investigate the rate of change (ROC) of Bruch’s membrane opening minimum rim width (BMO-MRW) and peripapillary retinal nerve fiber layer (RNFL) thickness in early normal tension glaucoma (NTG) patients. Methods: in this longitudinal cohort study, 115 subjects (115 eyes) diagnosed as early NTG (mean deviation > −6.0 dB) and who had completed more than five times of spectral-domain optical coherence tomography (OCT) tests with acceptable quality were included. Measurement of BMO-MRW and RNFL were performed at 3-month intervals by OCT. Linear mixed-effects model was employed to calculate the ROC in global region and six Garway-Heath sectors with adjusting age, sex, and BMO area. Results: Average follow-up was 20.99 ± 6.99 months with OCT number of 7.54 ± 2.12. Baseline intraocular pressure was 14.72 ± 2.70 mmHg and MD was −2.73 ± 2.26 dB. ROC of global BMO-MRW was −2.06 ± 0.65 µm/yr and RNFL was −0.96 ± 0.16 µm/yr (p = 0.098). The most rapid ROC was in inferotemporal sector (BMO-MRW: −3.02 ± 0.88 µm/yr, RNFL: −1.96 ± 0.36 µm/yr) followed by superotemporal sector. Conclusion: The ROC of BMO-MRW, the new parameter along with that of RNFL should be considered in the management of early NTG. BMO-MRW may show visible reduction ROC better than RNFL to detect early progression in early NTG when visual field may not show significant change.

Clinical Predictors of the Region of First Structural Progression in Early Normal-tension Glaucoma.

PurposeThis study aimed to compare the clinical characteristics of patients who showed structural progression in the peripapillary retinal nerve fiber layer (RNFL) first against those who showed progression in the macular ganglion cell-inner plexiform layer (GCIPL) first and to investigate clinical parameters that help determine whether a patient exhibits RNFL or GCIPL damage first.MethodsA retrospective review of medical records of patients diagnosed with early-stage normal-tension glaucoma was performed. All eyes underwent intraocular pressure measurement with Goldmann applanation tonometer, standard automated perimetry, and Cirrus optical coherence tomography at 6-month intervals. Structural progression was determined using the Guided Progression Analysis software. Blood pressure was measured at each visit.ResultsForty-one eyes of 41 patients (mean age, 52.6 ± 16.7 years) were included in the study. In 21 eyes, structural progression was first detected in the RNFL at 54.2 ± 14.8 months, while structural progression was first observed at the macular GCIPL at 40.5 ± 11.0 months in 20 eyes. The mean intraocular pressure following treatment was 13.1 ± 1.8 mmHg for the RNFL progression first group and 13.4 ± 1.8 mmHg for the GCIPL progression first group (p = 0.514). The GCIPL progression first group was older (p = 0.008) and had thinner RNFL at baseline (p = 0.001). The logistic regression analyses indicated that both age and follow-up duration until first progression predicted the region of structural progression (odds ratio, 1.051; 95% confidence interval, 1.001–1.105; p = 0.046 for age; odds ratio, 0.912; 95% confidence interval, 0.840–0.991; p = 0.029 for time until progression).ConclusionsAge of glaucoma patients and time until progression are associated with the region of the first structural progression in normal-tension glaucoma. Further studies exploring the association between glaucomatous progression and the location of damage are needed.

Topographic correlation between macular superficial microvessel density and ganglion cell-inner plexiform layer thickness in glaucoma-suspect and early normal-tension glaucoma

Background/AimsTo investigate the topographic relationship between macular superficial microvessel density (SMD) and macular ganglion cell-inner plexiform layer (GCIPL) thickness in eyes with glaucoma-suspect (GS) and early normal-tension glaucoma (NTG).MethodsA total...

Relationship between Macular Vessel Density and Focal Electroretinograms in Early Normal Tension Glaucoma

ABSTRACTPurpose: To evaluate the relationship between the macular vessel density and photopic negative response (PhNR) amplitude of focal electroretinograms (ERGs) in patients with early-stage normal tension glaucoma (NTG).Materials and Methods: This prospective cross-sectional study included a total of 42 subjects with early-stage NTG. Optical coherence tomography angiography was used to measure macular vessel density, and focal ERGs were elicited by a white light stimulus (30 cd/m2) with background light (1.5 cd/m2). The amplitude of the PhNR was measured from the peak of the b-wave to the PhNR trough. Mean visual field sensitivity was measured by the Humphrey Field Analyzer (HFA) program central 10–2. Spearman’s coefficients were used to evaluate the correlation between the macular vessel density, PhNR amplitude, mean deviation (MD) of the HFA 10–2, retinal nerve fiber layer (RNFL) thickness, and ganglion cell complex (GCC) thickness measured by spectral domain-optical coherence tomography.Results: The mean MD of the HFA 10–2 was −2.0 ± 3.2 dB. The PhNR amplitude significantly correlated with the macular vessel density (r = 0.420, P = 0.006), but not with the MD, GCC thickness, or RNFL thickness. The macular vessel density significantly correlated with the MD (r = 0.364, P = 0.018) and RNFL thickness (r = 0.369, P = 0.016), but not with GCC thickness (r = 0.266, P = 0.089).Conclusions: Macular vessel density significantly correlated with PhNR amplitude in patients with early-stage NTG, suggesting that microvascular alterations are associated with functional changes recorded by focal ERG in very early-stage glaucoma.

Segmental inner macular layer analysis with spectral-domain optical coherence tomography for early detection of normal tension glaucoma.

PurposeTo segment the inner macular layers (IML) and compare the discriminating abilities of the macular and peripapillary retinal nerve fiber layer (mRNFL and pRNFL, respectively) thicknesses in patients with early-stage normal tension glaucoma (NTG).DesignCross-sectional studyMethodsForty-nine normal subjects and 69 preperimetric glaucoma (PPG) and 60 NTG patients were enrolled. Spectral-domain optical coherence tomography (SD-OCT) was used to obtain pRNFL and macular thickness parameters and segment the IML in all subjects. Area under the receiver operating characteristic (AUROC) curves were used to compare the diagnostic capabilities of different parameters.ResultsThe pRNFL, total macular layer (TML), mRNFL, and macular ganglion cell layer (mGCL) were significantly thinner in the NTG group than in the PPG and normal groups. The global and superotemporal pRNFL and the mGCL in the superior outer area were the three best parameters for detecting early NTG. The discriminating capabilities of the superior and inferior mGCL were comparable to those of the corresponding pRNFL (p = 0.573, 0.841). Concerning location, the mGCL had higher AUROCs in the outer sectors (0.863, 0.837) than in the inner sectors (0.747, 0.747). Pearson’s correlation coefficients also revealed significant correlations between the mGCL and pRNFL (superior: r = 0.499, inferior: r = 0.624). The strongest correlation was between the mGCL and mean deviation (MD) (superior: r = 0.434 and inferior: r = 0.402).ConclusionsThe diagnostic value of mGCL thickness is comparable to that of pRNFL thickness. IMLs in the outer sectors had better diagnostic capabilities than those in the inner sector for detecting early NTG.

Intraocular retinal thickness asymmetry in early stage of primary open angle glaucoma and normal tension glaucoma.

To investigate the intraocular retinal thickness asymmetry of peripapillary retinal nerve fiber layer (pRNFL) and macular layers measured by spectral-domain optical coherence tomography (SD-OCT) in patients with early stage of primary open angle glaucoma (POAG) and normal tension glaucoma (NTG). A total of 117 patients with early stage of glaucoma (54 patients with POAG and 63 patients with NTG) and 32 normal subjects were recruited for the study. The pRNFL thickness, total macular layer (TML) thickness, and isolated inner macular layer (IML) thickness were measured by SD-OCT. Hemisphere TML thickness asymmetry measured by the posterior pole asymmetry scan was evaluated. Thickness differences of pRNFL and IML between superior and inferior quadrants were calculated. Asymmetry indices (AIs) of the pRNFL, TML and isolated IML were also computed. Areas under the receiver-operating characteristic curves (AROCs) were generated to determine the diagnostic capabilities of different parameters. Intraocular pRNFL thickness differences and AIs between the superior and inferior quadrants were significantly different between normal and NTG groups (P=0.009 and P<0.001, respectively). Intraocular pRNFL thickness differences and AIs between the temporal-superior and temporal-inferior sectors were also significantly different between normal and NTG groups (P=0.035 and P<0.001, respectively). The thickness differences and AIs of TML between superior and inferior hemispheres were significantly different between normal and NTG groups (P=0.001 and P=0.001, respectively) and between normal and POAG groups (P=0.032 and P=0.020, respectively). The thickness differences and AIs of macular ganglion cell layer (mGCL) between superior and inferior quadrants were significantly different between normal and NTG groups (P=0.013 and P=0.004, respectively), and between NTG and POAG groups (P=0.015 and P=0.012, respectively). The thickness difference of TML between superior and inferior hemispheres showed the highest diagnostic capability for early NTG eyes (AROC=0.832). Intraocular retinal thickness asymmetry in pRNFL, TML and mGCL are found in early stage of NTG. Hemisphere TML thickness asymmetry is also found in POAG eyes. Asymmetry analysis of retinal thickness can be an adjunctive modality for early detection of glaucoma.

Integrated electrophysiological evaluation in early normal-tension glaucoma

Purpose: To evaluate the variations of intraocular pressure (IOP), morphometric optic nerve head characteristic, perimetric indices and electrophysiological parameters (pattern electroretinogram and visual evoked potentials) before and after topical IOP lowering in patients with early normal-tension glaucoma.Methods: we evaluated 38 eyes of 20 patients with IOP &lt; 21 mmHg, initial glaucomatous optic neuropathy (valued with HRT: retinal nerve fiber layer thickness (RNFL) and linear cup/disk ratio (linear C/D ratio)), minimal visual field defects (Octopus 101: G2 program), best correct visual acuity more than 15/20 and pathological electrophysiological parameters (valued with pattern electroretinogram (PERG) and visual evoked potentials (VEPs)), free of systemic or other ocular diseases. All parameters were evaluated at the beginning of the study (T0) and after 12 months of therapy (T12). A randomized normal control group (27 eyes of 14 subjects) with apparent larger disc cupping underwent all exams at initial of study (T0) and after 12 months (T12).Results: Among electrophysiological parameters, at the beginning of the study NTG P100 VEPs latency is slightly increased and P100 amplitude is reduced compared to normal subjects. There are not significant variations after 12 months. P50 PERG latency in NTG is quite similar respect normal and do not modify after therapy. P50N95 complex PERG amplitude in NTG is reduced compared to normal subjects and slightly increases after 12 months (1.8 vs 1.5 ; 2.4 vs 1.9 micronvolts, with different checkboard spatial frequency). Cortical retinal time (CRT) is slightly delayed in NTG and does not modify. Among visual field indices, MD and CLV is slightly higher in NTG and do not significantly modify after therapy. Among morphometric optic nerve head characteristics, linear C/D and RNFL thickness are quite similar in NTG and do not modify. IOP is quite similar between NTG and control group and modifies in NTG after therapy.Conclusion: In a viewpoint of an integrated diagnostic, electrophysiological tests (VEPs and PERG) could provide a more sensitive measure of retinal ganglion cell integrity and help to distinguish between early normal-pressure glaucoma patients with no or minimal visual field alterations and normal subjects with apparent larger disc cupping.

Change in Central Corneal Thickness After the Discontinuation of Latanoprost in Normal Tension Glaucoma-Change in Central Corneal Thickness After Stop of Latanoprost

To assess the impact of latanoprost on central corneal thickness (CCT) after ceasing medication in patients with normal tension glaucoma (NTG). A total of 46 eyes from 46 NTG patients, and 44 eyes from 44 individuals with glaucoma suspect (controls), were included in this retrospective study. Newly diagnosed early NTG patients (visual field mean deviation >-6.00) were administered latanoprost 0.005% monotherapy once a day. CCTs were measured by ultrasound pachymetry before treatment, for 5 years during treatment, and for 2 years after ceasing treatment. Mean CCT was reduced significantly in the NTG group during treatment [544.4 ± 35.8 μm vs. 531.4 ± 32.5 μm (n = 46), P < 0.001]. After ceasing latanoprost treatment, mean CCT increased [531.4 ± 32.5 μm vs. 544.6 ± 37.1 μm (n = 46), P < 0.01] over the course of 2 years. In the control group, however, mean CCT was not significantly different [553.5 ± 27.5 μm vs. 561.8 ± 24.7 μm (n = 44), P = 0.06] at the 7-year follow-up. Latanoprost significantly reduced CCT in NTG patients after 5 years of treatment; however, the reduction was reversed 2 years after discontinuation of treatment.

The Effects of Nocturnal Dip and Blood Pressure Variability on Paracentral Scotoma in Early Open-Angle Glaucoma

ABSTRACTPurpose: To evaluate the effect of nocturnal dip and blood pressure (BP) variability on paracentral scotoma in early open-angle glaucoma. Methods: The present study included 72 early normal-tension glaucoma (NTG) patients and 34 early primary open-angle glaucoma (POAG) patients. Nocturnal dip and weighted standard deviation (wSD) were determined by 24-hour ambulatory BP monitoring (24-hr ABPM). The mean deviation (MD) and pattern deviation (PD) were measured with visual field. Correlations between nocturnal dip and/or BP variability and paracentral scotoma were assessed using Student’s t-test, Pearson’s correlation test, and linear logistic regression analysis. Results: The systolic and diastolic nocturnal dip and paracentral scotoma occurrence demonstrated a statistically significant correlation in the early NTG group (systolic nocturnal dip: p=0.047, diastolic nocturnal dip: p=0.011). In the early NTG group, the subgroup with paracentral scotoma had a greater nocturnal dip than those patients without paracentral scotoma (systolic nocturnal dip: p=0.000; diastolic nocturnal dip: p=0.000). In the early NTG group, the subgroup with paracentral scotoma had higher wSD of SBP than the patients without paracentral scotoma (p=0.003). In the logistic regression analysis of the factors that can affect paracentral scotoma SBP dip and SBP, wSD appeared to significantly affect the occurrence of paracentral scotoma in the early NTG group. Conclusions: Early NTG patients with paracentral scotoma have nocturnal dip and large BP variability. Therefore, in early glaucoma patients, particularly in early NTG with paracentral scotoma, nocturnal dip and BP variability should be assessed with 24-hr ABPM.