Risk factors for visual field progression of normal-tension glaucoma in patients with myopia

Longitudinal changes in optical coherence tomography angiography characteristics in normal-tension glaucoma with or without high myopia

PURPOSE

To evaluate the structural, microvascular, and functional progression of normal tension glaucoma (NTG) with or without high myopia by examining longitudinal changes in optical coherence tomography angiography (OCTA) and visual field (VF) parameters.

METHODS

We evaluated 61 NTG eyes and classified 25 of the eyes with axial lengths (ALs) of ≥26 mm as highly myopic. We assessed the rate of change in OCTA parameters, namely radial peripapillary capillary (RPC) vessel density (VD), parafovea VD, deep parafovea VD, retinal nerve fibre layer (RNFL) thickness, and ganglion cell complex thickness. We evaluated the correlation of the rate of change in OCTA parameters with VF loss and AL.

RESULTS

Among the 61 NTG eyes, rates of loss of RPC VD, parafovea VD, deep parafovea VD, and RNFL thickness were significantly different from zero despite the nonsignificant rate of change in VF mean deviation (MD). Changes in these OCTA parameters did not differ significantly in highly myopic NTG eyes. The rate of change in VF MD was significantly correlated with the rate of change in parafovea VD in highly myopic and non-highly myopic NTG eyes. In highly myopic NTG eyes, AL was negatively correlated with the rates of loss of RNFL thickness, VF MD, and VF PSD.

CONCLUSION

NTG eyes with a relatively stable VF exhibited loss of VD and RNFL thickness. VF progression in NTG was correlated with decreasing parafovea VD, indicating a structure-function correlation. Greater AL may indicate faster VF loss and RNFL thinning in highly myopic NTG eyes.

Clinical Characteristics and Associated Factors to the Development of Glaucoma in Eyes With Myopic Optic Neuropathy

PURPOSE

To observe the development of glaucoma in myopic eyes with and without myopic optic neuropathy (MON) and analyze associated factors to the development of typical glaucomatous damage.

DESIGN

A prospective, observational, cohort study.

METHODS

A total of 233 myopic eyes with no definite evidence of glaucomatous damage were included. Myopic patients without any retinal nerve fiber layer (RNFL) or visual field (VF) abnormalities were classified as myopic eyes without MON. Myopic patients with decreased RNFL at the superonasal (SN) or nasal area, and with corresponding VF defects either in the temporal or inferotemporal (IT) region were classified as myopic eyes with MON. Myopic eyes that developed glaucoma were defined by the presence of glaucomatous VF in the SN region including defects in Bjerrum area, or a new localized RNFL defect in the IT region. Disc morphological features and optic nerve head (ONH) parameters of two groups were compared.

RESULTS

Myopic eyes with MON had a thinner average peripapillary RNFL thickness (P < 0.001), worse MD of the VF (P = 0.031), a higher percentage of IT VF defects (P < 0.001), smaller torsion degree (P = 0.047), and greater LCD (P = 0.022). Myopic eyes with MON who developed glaucoma had a thinner average peripapillary RNFL thickness (P = 0.009), greater PPA area (P = 0.049), greater LCD (P < 0.001), and thinner LCT (P < 0.001). Thinner baseline temporal RNFL thickness (HR, 0.956; 95% CI, 0.928-0.986; P = 0.004), greater baseline LCD (HR, 1.003; 95% CI, 1.000-1.005; P = 0.022), and greater PPA area (HR, 1.000; 95% CI, 1.000-1.003; P = 0.050) were significantly associated factors with glaucoma development.

CONCLUSIONS

Myopic eyes with MON have a greater risk to develop glaucoma compared to myopic eyes without MON. Structural weakness due to myopia, especially at the temporal side of the ONH and the peripapillary sclera, increases the risk of glaucoma in myopic eyes with MON.

The protective effect of astaxanthin on the ganglion cell complex in glutamate/aspartate transporter deficient mice, a model of normal tension glaucoma, analyzed by spectral domain-optical coherence tomography

Astaxanthin (AST), a natural marine carotenoid, possess a wide variety of biological functions. In particular, as a strong antioxidant, AST effectively scavenges oxygen free radicals and reduces oxidative stress. In addition, recent in vitro studies have suggested that AST attenuates glutamate-induced apoptosis and cytotoxicity. The glutamate/aspartate transporter (GLAST) deficient (GLAST-/-) mouse is a mouse model of normal tension glaucoma (NTG) caused by both the glutamate neurotoxicity and oxidative stress in the retina. In the present study, we investigated the effects of AST on the ganglion cell complex, indicator of glaucomatous structural damage, using spectral domain-optical coherence tomography. As a result, AST significantly attenuated the thinning of ganglion cell complex in GLAST-/- mice in comparison to an AST-free control group. Our results suggest the possibility that AST has protective effects against glutamate neurotoxicity and oxidative stress in the retina. At present, the only treatment for NTG that is available in the clinical setting is to reduce the IOP as much as possible. Thus, our results suggest that AST supplementation may be effective for some types of NTG in which glutamate neurotoxicity and oxidative stress are involved.

Impact of myopia on the association of long-term intraocular pressure fluctuation with the rate of progression in normal-tension glaucoma

BACKGROUND/AIMS

To investigate whether the association of long-term intraocular pressure (IOP) fluctuation with the rate of progression of normal-tension glaucoma (NTG) differs between myopia and non-myopia.

METHODS

The medical records of 65 myopic NTG (axial length (AL) > 24.0 mm) and 64 non-myopic NTG eyes (AL < 24.0 mm), who had been treated with topical medications for more than 5 years, were reviewed. Multiple linear regression models were fitted to analyse the relationships of the slope of mean deviation (MD) or visual field index (VFI) with the clinical factors, including the interactions with myopia.

RESULTS

The average follow-up period was 8.3 years. Twenty-two (22) non-myopic eyes (34.4%) and 27 myopic eyes (41.5%) showed NTG progression (p=0.511). The interaction of myopia with IOP fluctuation was a significant factor regarding both MD and VFI slope (p=0.002, 0.024, respectively); stratified analyses suggested that the risk effect of IOP fluctuation was significant only in myopic NTG in terms of both MD (β= -1.27, p=0.003) and VFI slope (β=-2.32, p=0.011).

CONCLUSION

Long-term IOP fluctuation was significantly related to faster visual field progression in myopic NTG eyes, compared with non-myopic NTG eyes.

Age-Related Physiologic Thinning Rate of the Retinal Nerve Fiber Layer in Different Levels of Myopia

Purpose

To investigate the effect of refractive error on the physiologic thinning rate of the retinal nerve fiber layer (RNFL) in healthy eyes. Materials and Methods. This study analyzed 223 eyes of 141 healthy subjects followed for more than 5 years and underwent at least five serial spectral domain optical coherence tomography (SD-OCT) examinations. Longitudinal RNFL measurements were analyzed by linear mixed models incorporating follow-up duration, baseline RNFL thickness, spherical equivalent (SE), age, intraocular pressure, and visual field mean deviation. Thinning rates were classified according to SE into three groups: nonmyopic (NM; >0 D), mild-to-moderately myopic (MM; >–6 D and ≤0 D), and highly myopic (HM; ≤–6 D).

Results

The overall slopes of change in RNFL thickness over time in the NM, MM, and HM groups were −0.305 ± 0.128, −0.294 ± 0.068, and −0.208 ± 0.097 μm/yr, respectively. Slopes of RNFL thickness changes in these groups were −0.514 ± 0.248, −0.520 ± 0.133, and −0.528 ± 0.188 μm/yr, respectively. Slopes of RNFL thickness changes in these groups were −0.514 ± 0.248, −0.520 ± 0.133, and −0.528 ± 0.188 μm/yr, respectively. Slopes of RNFL thickness changes in these groups were −0.514 ± 0.248, −0.520 ± 0.133, and −0.528 ± 0.188 μm/yr, respectively. Slopes of RNFL thickness changes in these groups were −0.514 ± 0.248, −0.520 ± 0.133, and −0.528 ± 0.188 μm/yr, respectively. Slopes of RNFL thickness changes in these groups were −0.514 ± 0.248, −0.520 ± 0.133, and −0.528 ± 0.188 

Conclusions

Refractive error did not affect the physiologic thinning rate of RNFL when assessed by SD OCT.

Machine learning classifiers-based prediction of normal-tension glaucoma progression in young myopic patients

PURPOSE

To assess the performance of machine learning classifiers for prediction of progression of normal-tension glaucoma (NTG) in young myopic patients.

STUDY DESIGN

Cross-sectional study.

METHODS

One hundred and fifty-five eyes of 155 myopic NTG patients (axial length [AL] ≥ 24.00 mm and refractive error ≤ - 3.0 D) between the ages of 20 and 40 were enrolled and divided into training (110) and test (45) sets. Sixty-five eyes showed glaucoma progression as defined by standard automated perimetry, while 91 eyes (nonprogressors) had been stable over the course of a follow-up period of at least 3 years. Two machine learning classifiers were built using the random forest and extremely randomized trees (extra-trees) models. Baseline clinical measurements obtained only at the initial visit were used as input features. The area under the receiver operating characteristic curve (AUC) was calculated to evaluate the accuracy of prediction.

RESULTS

Mean age and AL did not significantly differ between the 2 groups on either the training or the test set. The extra-trees model achieved an AUC of 0.881 [95% CI 0.814-0.945], higher than that of the random forest model (0.811 [0.731-0.888]; P = 0.010). The extra-trees model also outperformed all the clinical measurements for prediction of NTG progression, including average macular ganglion cell-inner plexiform layer thickness (0.735 [0.639-0.831]) and average circumpapillary retinal nerve fiber layer thickness (0.691 [0.590-0.792]; both P < 0.001).

CONCLUSIONS

In young myopic patients, the machine learning classifier with the extra-trees model can predict glaucomatous progression more effectively than clinical diagnostic parameters.

Glaucoma Progression and its Relationship with Corrected and Uncorrected Intraocular Pressure in Eyes with History of Refractive Corneal Surgery

PURPOSE

To investigate glaucoma progression and its relationship with corrected and uncorrected intraocular pressure (IOP) in patients with a history of refractive corneal surgery (RCS).

METHODS

Totally, 56 eyes of 56 primary open-angle glaucoma patients who had a history of RCS were included. Mean keratometry and central corneal thickness were measured at the time of glaucoma diagnosis. Three IOP measurements, i.e., uncorrected IOP (_UCIOP) and corrected IOP calculated by applying the Kohlhaas (_CKIOP) and Ehlers (_CEIOP) formulas, were used. Participants were categorized into two groups (low-teen [<15 mmHg] and high-teen [≥15 mmHg] groups) according to the mean follow-up IOP, in each of the three IOP measurements. Glaucoma progression was determined based on either structurally or functionally by stereoscopic optic disc/retinal nerve fiber layer photographs or visual field tests. Kaplan-Meier survival curves were compared between the low-teens group and high-teens group for each IOP measurement. Risk factors for glaucoma progression, including uncorrected and corrected IOP measurements, were analyzed using a Cox proportional-hazards model.

RESULTS

Among total eyes, glaucoma progression was found in 19 (34%) eyes during 4.3 years of mean follow-up period. Individual values of uncorrected IOP and corrected IOP showed significant differences (p < 0.001). Incidence of glaucoma progression was higher in high-teens group than in low-teens group by corrected IOP values (both Kohlhaas and Ehlers, p = 0.006, 0.003), but not by uncorrected IOP values (p = 0.749). The cumulative probability of glaucoma progression was significantly greater in the high-teens group than in the low-teens group using the Elhers formula determined by Kaplan-Meier analysis (p = 0.030).

CONCLUSIONS

For glaucoma eyes with history of RCS, high-teen group by corrected mean follow-up IOP showed more glaucoma progression than low-teen group. More intensive IOP-lowering treatment will be required for patient with high-teen follow-up corrected IOP to prevent glaucoma progression.