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

The relationship between intraocular pressure and glaucoma: an evolving concept

Intraocular pressure (IOP) is the most important modifiable risk factor for glaucoma and fluctuates considerably within patients over short and long time periods. Our field's understanding of IOP has evolved considerably in recent years, driven by tonometric technologies with increasing accuracy, reproducibility, and temporal resolution that have refined our knowledge regarding the relationship between IOP and glaucoma risk and pathogenesis. The goal of this article is to review the published literature pertinent to the following points: 1) the factors that determine IOP in physiologic and pathologic states; 2) technologies for measuring IOP; 3) scientific and clinical rationale for measuring diverse IOP metrics in patients with glaucoma; 4) the impact and shortcomings of current standard-of-care IOP monitoring approaches; 5) recommendations for approaches to IOP monitoring that could improve patient outcomes; and 6) research questions that must be answered to improve our understanding of how IOP contributes to disease progression. Retrospective and prospective data, including that from landmark clinical trials, document greater IOP fluctuations in glaucomatous than healthy eyes, tendencies for maximal daily IOP to occur outside of office hours, and, in addition to mean and maximal IOP, an association between IOP fluctuation and glaucoma progression that is independent of mean in-office IOP. Ambulatory IOP monitoring, measuring IOP outside of office hours and at different times of day and night, provides clinicians with discrete data that could improve patient outcomes. Eye care clinicians treating glaucoma based on isolated in-office IOP measurements may make treatment decisions without fully capturing the entire IOP profile of an individual. Data linking home blood pressure monitors and home glucose sensors to dramatically improved outcomes for patients with systemic hypertension and diabetes and will be reviewed as they pertain to the question of whether ambulatory tonometry is positioned to do the same for glaucoma management. Prospective randomized controlled studies are warranted to determine whether remote tonometry-based glaucoma management might reduce vision loss and improve patient outcomes.

Sector-specific Association of Intraocular Pressure Dynamics in Dark-room Prone Testing and Visual Field Defect Progression in Glaucoma

PURPOSE

To investigate sectoral differences in the relationship between intraocular pressure (IOP) dynamics during dark-room prone testing (DRPT) and visual field (VF) defect progression in primary open-angle glaucoma (POAG) patients.

DESIGN

Retrospective, longitudinal study.

PARTICIPANTS

This retrospective study included 116 eyes of 84 POAG patients who underwent DRPT and had at least 5 reliable VF tests conducted over a more than 2-year follow-up period. We excluded eyes with mean deviation worse than -20 dB or a history of intraocular surgery or laser treatment.

METHODS

Average total deviation (TD) was calculated in the superior, central, and inferior sectors of the Humphrey 24-2 or 30-2 program. During DRPT, IOP was measured in the sitting position, and after 60 minutes in the prone position in a dark room, IOP was measured again. The relationship between IOP change during DRPT, IOP after DRPT, and TD slope in each quadrant was analyzed with a linear mixed-effects model, adjusting for other potential confounding factors.

MAIN OUTCOME MEASURES

Total deviation slope in each quadrant, IOP change during DRPT, and IOP after DRPT.

RESULTS

Intraocular pressure after DRPT and IOP change during DRPT were 18.16 ± 3.42 mmHg and 4.92 ± 3.12 mmHg, respectively. Superior TD slope was significantly associated with both IOP after DRPT (β = -0.28, P = 0.003) and IOP change during DRPT (β = -0.21, P = 0.029), while central (β = -0.05, P = 0.595; β = -0.05; P = 0.622) and inferior (β = 0.05, P = 0.611; β = 0.01, P = 0.938) TD slopes were not.

CONCLUSION

Dark-room prone testing might be a useful test to predict the risk of superior VF defect progression in eyes with POAG.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

The association between intraocular pressure dynamics during dark-room prone testing and intraocular pressure over a relatively long-term follow-up period in primary open-glaucoma patients

PURPOSE

To investigate the relationship between the dynamics of intraocular pressure (IOP) during dark-room prone testing (DRPT) and IOP over a relatively long-term follow-up period.

METHODS

This retrospective study enrolled 84 eyes of 51 primary open-angle glaucoma patients who underwent DRPT for whom at least three IOP measurements made using Goldmann applanation tonometry were available over a maximum follow-up period of two years. We excluded eyes with a history of intraocular surgery or laser treatment and those with changes in topical anti-glaucoma medication during the follow-up period. In DRPT, IOP was measured in the sitting position, and after 60 min in the prone position in a dark room, IOP was measured again. In this study, IOP fluctuation refers to the standard deviation (SD) of IOP, and IOP max indicates the maximum value of IOP during the follow-up. The relationship between these parameters was analyzed with a linear mixed-effects model, adjusting for clinical parameters including age, gender, and axial length.

RESULTS

IOP increased after DRPT with a mean of 6.13 ± 3.55 mmHg. IOP max was significantly associated with IOP after DRPT (β = 0.38; p < 0.001). IOP fluctuation was significantly associated with IOP change in DRPT (β = 0.29; p = 0.007).

CONCLUSION

Our findings suggest that short-term and relatively long-term IOP dynamics are associated. Long-term IOP dynamics can be predicted by DRPT to some extent.

Influence of choroidal microvasculature dropout on progressive retinal nerve fibre layer thinning in primary open-angle glaucoma: comparison of parapapillary β-zones and γ-zones

BACKGROUND/AIMS

To compare the influence of choroidal microvasculature dropout (cMvD) on progressive retinal nerve fibre layer (RNFL) thinning in glaucomatous eyes with parapapillary β-zones and γ-zones.

METHODS

294 eyes with primary open-angle glaucoma (POAG) and parapapillary atrophy (PPA) underwent optical coherence tomography (OCT) to determine the type of PPA and OCT angiography scanning of the optic nerve head to determine the presence of cMvD. Eyes were classified based on the type of PPA (β-zones and γ-zones), and their clinical characteristics were compared. Factors associated with the rate of rapid progressive RNFL thinning were determined in each group, including the presence of cMvD as an independent variable.

RESULTS

Of the 294 eyes, 186 and 108 were classified as having β-zones and γ-zones, respectively. The rate of RNFL thinning was slower (p<0.001), axial length was longer (p<0.001) and presence of cMvD was less frequent (57.4% vs 73.1%, p=0.006) in eyes with γ-zone than those with β-zone. Multivariate analyses showed that greater lamina cribrosa curvature (p=0.047) and the presence of cMvD (p=0.010) were associated with a faster rate of RNFL thinning in eyes with β-zone, whereas larger intraocular pressure fluctuation (p<0.001), shorter axial length (p=0.042) and greater baseline RNFL thickness (p<0.001) were associated with a faster rate of RNFL thinning in eyes with γ-zone.

CONCLUSIONS

The presence of cMvD was significantly associated with a faster rate of RNFL thinning in POAG eyes with β-zone, but not γ-zone. The pathogenic consequences of cMvD in POAG eyes may depend on accompanying peripapillary structures.

Mendelian Randomization Implicates Bidirectional Association between Myopia and Primary Open-Angle Glaucoma or Intraocular Pressure

PURPOSE

Observational studies suggest that myopic eyes carry a greater risk of primary open-angle glaucoma (POAG); however, the evidence for this association is inconsistent. This may be the result of confounding factors that arise from myopia that complicate clinical tests for glaucoma. This study used Mendelian randomization (MR) analysis to determine genetic causal associations among myopia, glaucoma, and glaucoma-related traits that overcome the effects of external confounders.

DESIGN

Bidirectional genetic associations between myopia and refractive spherical equivalent (RSE), POAG, and POAG endophenotypes were investigated.

PARTICIPANTS

Data from the largest publicly available genetic banks (n = 216,257-542,934) were analyzed.

METHODS

Multiple MR models and multivariate genomic structural modeling to identify significant mediators for the relationship between myopia and POAG.

MAIN OUTCOME MEASURES

Genetic causal associations between myopia and POAG and POAG endophenotypes.

RESULTS

We found consistent bidirectional genetic associations between myopia and POAG and between myopia and intraocular pressure (IOP) using multiple MR models at Bonferroni-corrected levels of significance. Intraocular pressure showed the most significant mediation effect on RSE and POAG (Sobel test, 0.13; 95% confidence interval, 0.09-0.17; P = 1.37 × 10^-8).

CONCLUSIONS

A strong bidirectional genetic causal link exists between myopia and POAG that is mediated mainly by IOP. Our findings suggest that IOP-lowering treatment for glaucoma may be beneficial in myopic eyes, despite the challenges of establishing a clear clinical diagnosis.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Relationship between Diurnal Variation in Intraocular Pressure and Central Corneal Power

SIGNIFICANCE

Relationship between intraocular pressure (IOP) change and central corneal curvature is complicated by measurement techniques and corneal biomechanical parameters. Findings from this study indicate that it is worthwhile to observe the association between diurnal change in IOP and corneal power.

PURPOSE

This study aimed to investigate the relationship between the diurnal change in IOP and central corneal power among eyes with and without myopia.

METHODS

Sixty healthy eyes of 24 emmetropes and 36 myopes were recruited for this cross-sectional study. Both anterior and posterior central corneal powers of the steep (Ks), flat (Kf), mean meridian (Km), best-fit spheres, and central corneal thickness were recorded followed by the IOP (Goldmann-correlated IOP [IOPg] and corneal-compensated IOP) and corneal biomechanics (corneal hysteresis and corneal resistance factor). Measurements were obtained every 3 hours from 9.30 am to 6.30 pm . Linear-mixed model was used to determine the relationship between the change in IOP and the associated change in corneal measurements (adjusted for age, sex, refractive error, central corneal thickness, and biomechanics) among the myopic and nonmyopic eyes.

RESULTS

Group mean, amplitude of change, and the diurnal change in IOPg were (mean ± standard deviation) 15.14 ± 2.50, 3.33 ± 1.44, and 1.81 ± 1.25 mmHg, respectively. Overall, an IOP increase was associated with a decrease in the adjusted anterior corneal powers. Myopic eyes were associated with a decrease of 0.04 D (95% confidence interval [CI], 0.07 to 0.01 D; P = .02) in Ks and 0.03 D (95% CI, 0.06 to 0.001 D; P = .047) in Kf per mmHg increase in IOP, whereas for emmetropes, per mmHg increase in IOP only flattened the Kf by 0.03 D (95% CI, 0.06 to 0.004 D; P = .02).

CONCLUSIONS

Change in anterior corneal power was inversely related to the change in IOPg, with myopic and nonmyopic eyes reporting a significant but differential impact of IOP. Clinicians must keep in mind the impact of large IOP fluctuation on the anterior corneal power.

Baseline 10-2 Visual Field Loss as a Predictor for Future Glaucoma Progression

PRCIS

Presence of baseline 10-2 visual field (VF) loss was the strongest predictor of future rate of 24-2 VF loss and development of new 24-2 progression events, suggesting a role for 10-2 VF testing in baseline glaucoma risk analysis.

PURPOSE

The purpose of this study is to examine the relationship between baseline 10-2 VF loss and future 24-2 VF loss.

MATERIALS AND METHODS

Subjects were participating in a prospective longitudinal study within a VA Medical Center outpatient eye clinic. Eligibility required 2 good quality baseline 10-2 VF tests followed by a minimum of 5 good quality 24-2 VF tests over at least 3 years. Longitudinal 24-2 VF testing was completed every 4-6 months after baseline 10-2 testing. Mixed model regression analyses and Cox Proportional Hazard regression analyses were completed to identify predictors of 24-2 mean deviation change rate and new VF loss events.

RESULTS

We studied 394 eyes of 202 subjects (119 primary open angle glaucoma and 83 glaucoma suspect). Over 6.7 (±1.5) years, 9.9 (±2.3) good quality 24-2 VF tests were completed. In mixed model regression analyses, baseline variables that predicted faster rate of 24-2 VF loss in order of strength of association were presence of baseline 10-2 VF defect, lower 24-2 mean deviation, and higher age. When analyses were completed without 10-2 variables, predictive capability of the model was reduced compared with when 10-2 variables were included. In Cox Proportional Regression analyses evaluating progression events, baseline 10-2 VF defect demonstrated the largest hazard ratio (22 times greater risk for developing future VF loss event in eyes with vs. without baseline 10-2 VF loss).

CONCLUSIONS

Baseline 10-2 VF defect was the most effective predictor of subsequent 24-2 VF progression in this study. These findings imply that presence of baseline 10-2 VF loss may provide unique value for predicting future glaucoma progression.

Comparison of visual outcomes of a diffractive trifocal intraocular lens and a refractive bifocal intraocular lens in eyes with axial myopia: a prospective cohort study

Background

To assess and compare the efficacy, safety, accuracy, predictability and visual quality of a diffractive trifocal intraocular lens (IOL) and a refractive rotationally asymmetric bifocal IOL in eyes with axial myopia.

Methods

This prospective cohort study enrolled patients with implantation of the diffractive trifocal IOL or the refractive bifocal IOL. Eyes were divided into four groups according to the IOL implanted and axial length. Manifest refraction, uncorrected and corrected visual acuity at far, intermediate and near distances, prediction error of spherical equivalent (SE), contrast sensitivity and aberrations were evaluated three months after surgery.

Results

In total, 80 eyes of 80 patients were included: 20 eyes in each group. Three months postoperatively, the corrected distance visual acuity of two trifocal groups were significantly better than the axial myopia bifocal group (P = 0.007 and 0.043). There was no significant difference of postoperative SE (P = 0.478), but the SE predictability of the trifocal IOL was better, whether in axial myopia groups (P = 0.015) or in control groups (P = 0.027). The contrast sensitivity was similar among four groups. The total aberration, higher order aberration and trefoil aberration of bifocal groups were significantly higher (all P < 0.001).

Conclusions

The diffractive trifocal IOL and the refractive bifocal IOL both provided good efficacy, accuracy, predictability and safety for eyes with axial myopia. By contrast, the trifocal IOL had a better performance in corrected distance visual acuity and visual quality.

Trial registration

The study was retrospectively registered and posted on clinicaltrials.gov at 12/02/2020 (NCT04265846).

A Review of Intraocular Pressure (IOP) and Axial Myopia

The pathogenesis of myopia is driven by genetic and environmental risk factors. Accommodation not only alters the curvature and shape of the lens but also involves contraction of the ciliary and extraocular muscles, which influences intraocular pressure (IOP). Scleral matrix remodeling has been shown to contribute to the biomechanical susceptibility of the sclera to accommodation-induced IOP fluctuations, resulting in reduced scleral thickness, axial length (AL) elongation, and axial myopia. The rise in IOP can increase the burden of scleral stretching and cause axial lengthening. Although the accommodation and IOP hypotheses were proposed long ago, they have not been validated. This review provides a brief and updated overview on studies investigating the potential role of accommodation and IOP in myopia progression.

Association of progressive optic disc tilt with development of retinal nerve fibre layer defect in children with large cup-to-disc ratio

BACKGROUND/AIMS

Whereas myopic optic disc deformation has been posited as a risk factor for glaucomatous damage, longitudinal studies evaluating their association have been sparse. We investigated whether the optic nerve head (ONH)'s morphological alteration during myopia progression play any role in development of retinal nerve fibre layer defect (RNFLD) in children with a large vertical cup-to-disc ratio (vCDR).

METHODS

Sixty-five normotensive eyes of 65 children aged under 8 years with (1) vCDR ≥0.5 but no additional signs of glaucoma and (2) who could be tracked at young adulthood (18-28 years) were included. Children's spherical equivalent (SE), intraocular pressure, vCDR and optic disc tilt ratio were recorded. Rare events logistic regression analysis was employed to identify factors associated with RNFLD-development risk.

RESULTS

The study group's mean age was 5.4±1.3 years, its average vCDR was 0.62±0.07, and the average SE was -0.3±1.4 dioptres ((D), range -3.15 to 2.75D) at the baseline. After an average follow-up of 16.1±3.0 years, the mean vCDR was 0.64±0.09, and the mean SE, -3.2±2.2D (range -7.25 to 0.00 D). Among the 65 eyes, 12 (18.5%) developed RNFLD. A greater SE change (OR=1.737, p=0.016) and a greater increase in tilt ratio (OR=2.364, p=0.002) were both significantly associated with higher RNFLD-development risk.

CONCLUSION

In this cohort of Korean children with large vCDR, progressive optic disc tilt in the course of myopia progression was associated with higher RNFLD-development risk. This finding suggests that morphological alterations in the ONH during axial elongation might represent an underlying susceptibility to glaucomatous damage in large-vCDR children.

Comparison of Medical Comorbidity between Patients with Normal-Tension Glaucoma and Primary Open-Angle Glaucoma: A Population-Based Study in Taiwan

The objective was to investigate different comorbidities developed in normal-tension glaucoma (NTG) and primary open-angle glaucoma (POAG) patients. This was a case-control study, with 1489 people in the NTG group and 5120 people in the POAG group. Patient data were obtained from the Longitudinal Health Insurance Database 2010 (LHID2010) of Taiwan for the 2008-2013 period. The chi-square test was used to compare categorical variables, such as gender, income and urbanisation level, between NTG and POAG patients, and the two-tailed t test was used to compare continuity between the two groups. We use a multivariate logic regression model to assess the risk of each participant. The results are expressed in terms of odds ratio (OR) and 95% confidence intervals (CI). Patients with NTG had significantly higher proportions of hypotension (adjusted OR, 1.984; 95% CI, 1.128-3.490), sleep disturbances (adjusted OR, 1.323; 95% CI, 1.146-1.528), peptic ulcers (adjusted OR, 1.383; 95% CI, 1.188-1.609) and allergic rhinitis (adjusted OR, 1.484; 95% CI, 1.290-1.707) than those with POAG. Conversely, arterial hypertension (adjusted OR, 0.767; 95% CI, 0.660-0.893), diabetes (adjusted OR, 0.850; 95% CI, 0.728-0.993) and atopic dermatitis (adjusted OR, 0.869; 95% CI, 0.763-0.990) had a lower risk in the NTG group than in the POAG group. We found that comorbidities such a hypotension, sleep disturbances and peptic ulcer and allergic rhinitis are more highly associated to NTG than POAG.

Impact of intraocular pressure fluctuations on progression of normal tension glaucoma

AIM

To investigate short- and long-term intraocular pressure (IOP) fluctuations and further ocular and demographic parameters as predictors for normal tension glaucoma (NTG) progression.

METHODS

This retrospective, longitudinal cohort study included 137 eyes of 75 patients with NTG, defined by glaucomatous optic disc or visual field defect with normal IOP (<21 mm Hg), independently from therapy regimen. IOP fluctuation, mean, and maximum were inspected with a mean follow-up of 38mo [standard deviation (SD) 18mo]. Inclusion criteria were the performance of minimum two 48-hour profiles including perimetry, Heidelberg retina tomograph (HRT) imaging, and optic disc photographs. The impact of IOP parameters, myopia, sex, cup-to-disc-ratio, and visual field results on progression of NTG were analyzed using Cox regression models. A sub-group analysis with results from optical coherence tomography (OCT) was performed.

RESULTS

IOP fluctuations, average, and maximum were not risk factors for progression in NTG patients, although maximum IOP at the initial IOP profile was higher in eyes with progression than in eyes without progression (P=0.054). The 46/137 (33.5%) eyes progressed over the follow-up period. Overall progression (at least three progression confirmations) occurred in 28/137 eyes (20.4%). Most progressions were detected by perimetry (36/46). Long-term IOP mean over all pressure profiles was 12.8 mm Hg (SD 1.3 mm Hg); IOP fluctuation was 1.4 mm Hg (SD 0.8 mm Hg). The progression-free five-year rate was 58.2% (SD 6.5%).

CONCLUSION

Short- and long-term IOP fluctuations do not result in progression of NTG. As functional changes are most likely to happen, NTG should be monitored with visual field testing more often than with other devices.

Risk Factors for the Structural Progression of Myopic Glaucomatous Eyes with a History of Laser Refractive Surgery

As laser refractive surgeries (LRS) have been widely performed to correct myopia, ophthalmologists easily encounter patients with glaucoma who have a history of LRS. It is well known that intraocular pressure (IOP) in eyes with glaucoma is not accurate when measured using Goldmann applanation tonometry. However, risk factors for glaucoma progression, particularly those associated with measured IOP, have rarely been studied. We analysed data for 40 patients with a history of LRS and 50 age-matched patients without a history of LRS. Structural progression was defined as significant changes in thickness in the peripapillary retinal nerve fibre layer as identified using optical coherence tomography event-based guided progression analysis. Risk factors were determined via Cox regression analysis. Disc haemorrhage (DH) was associated with glaucoma progression in both the non-LRS group and LRS group (hazard ratio (HR): 4.650, p = 0.012 and HR: 8.666, p = 0.019, respectively). However, IOP fluctuation was associated with glaucoma progression only in the LRS group (HR: 1.452, p = 0.023). Our results show that DH was a significant sign of progression in myopic glaucoma eyes. When treating patients with myopia and glaucoma, IOP fluctuation should be monitored more carefully, even if IOP seems to be well controlled.

Characteristics of progressive temporal visual field defects in patients with myopia

Temporal visual field damage (VFD) is the common type of non-glaucomatous VF defects found in eyes with myopia. However, little is known about the factors associated with its progression. We investigated the characteristic of myopic eyes with progressive temporal VF defects. This retrospective, observational study included a total of 116 eyes: 39 eyes with temporal VFDs and an axial length greater than 24.5 mm, 77 eyes with typical glaucomatous VFDs who were followed up more than 5 years. VF progression was evaluated with Trend-based global progression analysis. In the temporal VFD group, the greater tilt ratios, the higher prevalence of β-zone peripapillary atrophy (β-PPA), the substantial increase in β-PPA were found, compared to the typical glaucomatous VFD groups (all P-values ≤ 0.001). The temporal VFD group had the slower progression than the typical glaucomatous VFD group on trend-based GPA (P = 0.047). In the multivariate linear regression analysis, the change of β-PPA area over years was related to temporal VFD progression (B, − 0.000088, P = 0.003). In conclusion, myopic eyes with the temporal VFD, which come with growing β-PPA area, should be monitored with extra caution.