Visual field loss in patients with normal-tension glaucoma under topical nipradilol or timolol: subgroup and subfield analyses of the nipradilol-timolol study

Changes in individuals' glaucoma progression velocity after IOP-lowering therapy: A systematic review

Primary open-angle glaucoma (POAG) is a chronic progressive optic neuropathy often associated with increased intraocular pressure (IOP). Monitoring glaucoma progression velocity, for example, the rate of change in global indices such as mean deviation (MD), is a common way to determine whether functional deterioration has occurred. This systematic review aims to assess changes in glaucoma progression velocity in response to IOP-lowering therapy at an individual level. A systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. A comprehensive search of PubMed, Cochrane CENTRAL, and ClinicalTrials.gov from database inception through November 12, 2023, was conducted for randomized clinical trials involving patients with POAG, normal tension glaucoma, or progressive ocular hypertension who received IOP-lowering therapy with a target IOP reduction ≥20% from baseline. Included trials were required to report visual field progression velocity information for individual patients before and after intervention. One study was found to meet inclusion criteria and, therefore, synthesis of data and meta-analysis were unable to be performed. The study reports on 139 eyes of 109 patients from the Ocular Hypertension Treatment Study who reached a POAG endpoint. In these patients, the post-treatment rate of MD change (-0.27 ± 0.7 dB/year) was significantly slower than the pre-treatment rate (-0.51 ± 0.8), P < 0.01. In addition, the rate of MD change significantly correlated with mean IOP reduction (p < 0.001). The singular study demonstrated that IOP-lowering therapy did variably slow glaucoma progression rate in that patient cohort. There is a need for more studies that focus on individual patients' responses to glaucoma treatment. Furthermore, this information should be used to classify the magnitude of patients' responsiveness to IOP reduction. Future studies should report pre- and post-intervention progression velocities.

Trabeculectomy With Antimetabolite Agents for Normal Tension Glaucoma: A Systematic Review and Meta-Analysis

Background

Evidence regarding the impact on visual field (VF), intraocular pressure (IOP), and antiglaucoma medications from trabeculectomy with antimetabolites for normal tension glaucoma (NTG) is conflicting because of insufficient study sample sizes. The aim of this study is to systematically assess VF progression rate, IOP control and antiglaucoma medication use after trabeculectomy with antimetabolites for progressing NTG.

Methods

We searched published articles on PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials from database inception to March 21, 2022. We selected studies that reported VF data before and after trabeculectomy with antimetabolite agents for NTG. We followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guidelines. Data were extracted by 2 independent reviewers, and a random-effects model was employed for the meta-analysis. Study outcomes were VF progression rates measured using the pooled mean deviation (MD) slope, changes in antiglaucoma medications, and IOP. Subgroup analyses of the MD slope according to mean age (over or under 65 years), baseline MD (over or under –12 dB), and baseline IOP (over or under 15 mmHg) were performed to determine the results’ robustness.

Results

We included 7 retrospective observational studies (Japan: 6 studies, United States: 1 study) comprising a total of 166 eyes. Mean preoperative VF MD slopes ranged from –0.52 to –1.05 dB/year. The meta-analysis demonstrated significant MD slope improvement after trabeculectomy (pooled mean difference: 0.54 dB/year, 95% CI: 0.40 to 0.67, I² = 9%). Mean age, baseline MD, and baseline IOP subgroup analyses revealed MD slope results were consistent with those of the main analyses. The mean IOP (pooled mean difference: –5.54 mmHg, 95% CI: –6.02 to –5.06, I² = 0%) and mean number of antiglaucoma medications (pooled mean difference: –1.75, 95% CI: –2.97 to –0.53, I² = 98%) significantly decreased after trabeculectomy. The most frequently reported early complications after trabeculectomy were hypotony, hyphema, and shallow anterior chamber.

Conclusion

This systematic review and meta-analysis indicated that trabeculectomy with antimetabolites is beneficial for progressing NTG; it preserves visual function by alleviating the MD slope and reducing antiglaucoma medication use. However, several post-trabeculectomy complications should be monitored.

Central visual field change after fornix-based trabeculectomy in Japanese normal-tension glaucoma patients managed under 15 mmHg

PURPOSE

To investigate how the central visual field would be changed after fornix-based trabeculectomy with mitomycin C in Japanese normal-tension glaucoma (NTG) patients monitored for more than 10 years including before surgery.

METHODS

This is a retrospective cohort study. We identified twenty-eight eyes of 28 NTG cases regularly monitored for more than 5 years and examined static visual field (VF) tests for more than five times before and after fornix-based trabeculectomy (including combined surgery). Based on preoperative data for 6.3 years, we evaluated postoperative changes for 6.0 years in 10-2 VF and 30-2 VF.

RESULTS

Six patients were male and 22 females, the mean age was 57.9 years, and the mean deviation was - 13.7 decibels. After surgery, mean IOP decreased from 13.9 to 9.0 mmHg (P ≤ 0.01), and medication score also did. The rate of 10-2 VF deterioration was significantly suppressed from - 1.0 dB/year preoperatively to - 0.4 dB/year postoperatively (P ≤ 0.01). And when 30-2 VF was divided into six relevant sectors, the rate of deterioration at cecocentral and arcuate areas of the superior hemifield was suppressed postoperatively (P ≤ 0.01 and P = 0.042, respectively).

CONCLUSION

Based on long-term preoperative data, a significant positive change in 10-2 VF was observed after fornix-based trabeculectomy with mitomycin C in Japanese NTG patients with a mean IOP of 13.9 mmHg. Central vision could be expected to be maintained for NTG patients even if its preoperative IOP is low after successful trabeculectomy.

Evaluation of the relationship between glaucomatous disc subtypes and occurrence of disc hemorrhage and glaucoma progression in open angle glaucoma

To compare the occurrence of disc hemorrhages (DH) and glaucoma progression in open-angle glaucoma (OAG) patients with different glaucomatous disc types. Prospective, hospital-based, observational cohort study. OAG patients examined between 2000 and 2005, whose discs were classified as typical myopic glaucomatous (MG), generalized enlargement of cup (GE), or focal glaucomatous (FG) disc type were included and followed for 5 years. The first occurrence of DH during follow-up was analyzed using Kaplan-Meier analysis and difference in DH occurrence based on glaucomatous disc type using the Cox proportional-hazards model to adjust for effects of confounding factors. For inter-group comparison of glaucoma progression, the change rate of the mean deviation, Collaborative Initial Glaucoma Treatment Study scores, and fundus photographs were used. Thirty-nine patients with MG-, 18 with FG-, and 17 with GE-disc types were included. No significant inter-group difference was seen in the rate of glaucoma progression. The five-year probability of DH occurrence was much lower with MG- than with FG- or GE-disc types (P < 0.0220). The central corneal thickness (P = 0.0024) and mean intraocular pressure and its variations (P = 0.0450, 0.0219) contributed to DH occurrence. The MG-disc type demonstrated a much lower DH occurrence during follow-up than other disc types.

The nitric oxide-guanylate cyclase pathway and glaucoma

Glaucoma is a prevalent optic neuropathy characterized by the progressive dysfunction and loss of retinal ganglion cells (RGCs) and their optic nerve axons, which leads to irreversible visual field loss. Multiple risk factors for the disease have been identified, but elevated intraocular pressure (IOP) remains the primary risk factor amenable to treatment. Reducing IOP however does not always prevent glaucomatous neurodegeneration, and many patients progress with the disease despite having IOP in the normal range. There is increasing evidence that nitric oxide (NO) is a direct regulator of IOP and that dysfunction of the NO-Guanylate Cyclase (GC) pathway is associated with glaucoma incidence. NO has shown promise as a novel therapeutic with targeted effects that: 1) lower IOP; 2) increase ocular blood flow; and 3) confer neuroprotection. The various effects of NO in the eye appear to be mediated through the activation of the GC- guanosine 3:5'-cyclic monophosphate (cGMP) pathway and its effect on downstream targets, such as protein kinases and Ca²⁺ channels. Although NO-donor compounds are promising as therapeutics for IOP regulation, they may not be ideal to harness the neuroprotective potential of NO signaling. Here we review evidence that supports direct targeting of GC as a novel pleiotrophic treatment for the disease, without the need for direct NO application. The identification and targeting of other factors that contribute to glaucoma would be beneficial to patients, particularly those that do not respond well to IOP-dependent interventions.

Preperimetric Glaucoma Prospective Study (PPGPS): Predicting Visual Field Progression With Basal Optic Nerve Head Blood Flow in Normotensive PPG Eyes

Purpose

To investigate the site specificity of visual field changes in eyes with normotensive preperimetric glaucoma (PPG), and to determine factors influencing visual field progression.

Methods

This prospective study comprised 84 eyes of 84 normotensive PPG patients followed for at least 16 months. Optic nerve head (ONH) blood flow was assessed with tissue-area mean blur rate (MBR_T), derived from laser speckle flowgraphy. Total deviation (TD) was measured in each sector of the Garway-Heath map to evaluate the site specificity of visual field loss. Subjects with a TD slope in the first quartile were classified as progressive, and other subjects as nonprogressive. Linear and multiple regression analyses were performed to determine factors affecting visual field progression.

Results

TD in the superior sector significantly decreased in the subjects overall during the follow-up periods (−0.48 ± 1.92 dB/y, P = 0.025). Linear regression analysis showed that basal MBR_T-inferior was correlated significantly with TD-superior slope (r = 0.332, P = 0.002). Furthermore, basal MBR_T was significantly lower in this sector in the progressive than the nonprogressive group (P = 0.010). Multiple linear regression analysis revealed that basal MBR_T-inferior was the only predictive factor for TD-superior slope (β = 0.329, P = 0.005).

Conclusions

These findings suggest that superior-sector visual field progression is most common in normotensive PPG eyes, and that reduced basal ONH blood flow is associated with visual field progression.

Translational Relevance

These findings provide new insight into the involvement of ONH blood flow impairment in glaucoma pathogenesis, and demonstrate the importance of assessing ONH blood flow to determine visual field progression in normotensive PPG.

Impact of intraocular pressure reduction on visual field progression in normal-tension glaucoma followed up over 15 years

PURPOSE

To investigate the impact of surgical or medical reduction of intraocular pressure (IOP) on progressive normal-tension glaucoma followed up over 15 years.

METHODS

Sixty eyes of 60 patients were divided into 3 intervention groups: group 1 (trabeculectomy, n = 17); group 2 (IOP reduction rate ≥15% with prostaglandin analogs, n = 24); and group 3 (IOP reduction rate <15% with prostaglandin analogs, n = 19). The preintervention and postintervention mean deviation (MD) slopes and IOP were compared. Factors associated with the rate of visual field progression were identified by multiple regression analysis.

RESULTS

The mean follow-up was 19.8 years. In group 1, the preintervention and postintervention IOPs were 14.7 ± 1.3 and 9.1 ± 2.0 mmHg, respectively (P < .001, 38% reduction). The MD slope decreased significantly after trabeculectomy (-0.86 ± 0.51 versus -0.19 ± 0.20 dB/y; P < .001). In group 2, the preintervention and postintervention IOPs were 14.7 ± 1.5 and 11.7 ± 1.2 mmHg, respectively (P < 0.001, 20% reduction), with significant differences in the MD slope (-0.52 ± 0.37 versus -0.31 ± 0.30 dB/y; P = .019). In group 3, the preintervention and postintervention IOPs were 14.4 ± 1.8 and 13.2 ± 1.6 mmHg, respectively (P < 0.001, 8% reduction), with no differences in the MD slope (-0.40 ± 0.27 versus -0.50 ± 0.65 dB/y; P > .05). Multiple regression analysis showed that the average IOP, IOP reduction rate, and preintervention MD slope were related to the extent of the postintervention reduction in the MD slope. The difference in the preintervention and postintervention MD slopes significantly correlated with the rate of IOP reduction (r = 0.559, P < .001).

CONCLUSIONS

A pressure-dependent maintenance effect of the visual field was confirmed in progressive normal-tension glaucoma.

Neuroprotection for treatment of glaucoma in adults

BACKGROUND

Glaucoma is a heterogeneous group of conditions involving progressive damage to the optic nerve, deterioration of retinal ganglion cells, and ultimately visual field loss. It is a leading cause of blindness worldwide. Open angle glaucoma (OAG), the most common form of glaucoma, is a chronic condition that may or may not present with increased intraocular pressure (IOP). Neuroprotection for glaucoma refers to any intervention intended to prevent optic nerve damage or cell death.

OBJECTIVES

The objective of this review was to systematically examine the evidence regarding the effectiveness of neuroprotective agents for slowing the progression of OAG in adults compared with no neuroprotective agent, placebo, or other glaucoma treatment.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 7), Ovid MEDLINE, Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE Daily (January 1946 to August 2016), Embase (January 1980 to August 2016), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to August 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 16 August 2016.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in which topical or oral treatments were used for neuroprotection in adults with OAG. Minimum follow-up time was four years.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed titles and abstracts from the literature searches. We obtained full-text copies of potentially relevant studies and re-evaluated for inclusion. Two review authors independently extracted data related to study characteristics, risk of bias, and outcomes. We identified one trial for this review, thus we performed no meta-analysis. Two studies comparing memantine to placebo are currently awaiting classification until study investigators provide additional study details. We documented reasons for excluding studies from the review.

MAIN RESULTS

We included one multicenter RCT of adults with low-pressure glaucoma (Low-pressure Glaucoma Treatment Study, LoGTS) conducted in the USA. The primary outcome was progression of visual field loss after four years of treatment with either brimonidine or timolol. Of the 190 adults enrolled in the study, the investigators excluded 12 (6.3%) after randomization; 77 participants (40.5%) did not complete four years of follow-up. The rate of attrition was unbalanced between groups with more participants dropping out of the brimonidine group (55%) than the timolol group (29%).Of those remaining in the study at four years, participants assigned to brimonidine showed less progression of visual field loss than participants assigned to timolol (risk ratio (RR) 0.35, 95% confidence interval (CI) 0.14 to 0.86; 101 participants). Because of high risk of attrition bias and potential selective outcome reporting, we graded the certainty of evidence for this outcome as very low. At the four-year follow-up, the mean IOP was similar in both groups among those for whom data were available (mean difference 0.20 mmHg, 95% CI -0.73 to 1.13; 91 participants; very low-certainty evidence). The study authors did not report analyzable data for visual acuity or any data related to vertical cup-disc ratio, quality of life, or economic outcomes. The most frequent adverse event was ocular allergy to the study drug, which affected more participants in the brimonidine group than the timolol group (RR 5.32, 95% CI 1.64 to 17.26; 178 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS

Although the only trial we included in this review found less visual field loss in the brimonidine-treated group, the evidence was of such low certainty that we can draw no conclusions from this finding. Further clinical research is needed to determine whether neuroprotective agents may be beneficial for individuals with OAG. Such research should focus on outcomes important to patients, such as preservation of vision, and how these outcomes relate to cell death and optic nerve damage. As OAG is a chronic, progressive disease with variability in symptoms, RCTs designed to measure the effectiveness of neuroprotective agents require a long-term follow-up of five years or longer to detect clinically meaningful effects.

Visual Field Progressive Rate in Normal Tension Glaucoma Before and After Trabeculectomy: A Subfield-Based Analysis

PURPOSE

To compare pretrabeculectomy and posttrabeculectomy progression rates in normal-tension glaucoma in 6 subfields of the central 30 visual field.

DESIGN

A retrospective study.

METHODS

Clinical records of 34 patients with normal-tension glaucoma (12 males and 22 females) with progressive visual field loss undergoing successful trabeculectomy were studied. The time course of the mean deviation (MD) and mean of total deviation in the superior/inferior arcuate, paracentral, and cecocentral subfields were analyzed using a linear mixed-effects model.

RESULTS

Patients' age, intraocular pressure (IOP), MD, and pretrabeculectomy and posttrabeculectomy follow-up averaged 57.7 ± 9.6 years, 15.7 ± 1.7 mm Hg, -12.7 ± 5.5 dB, and 4.6 ± 1.5 and 5.7 ± 1.2 years, respectively. Average IOP was lowered by 6.1 ± 3.3 to 10.3 ± 2.7 mm Hg (5-14 mm Hg) over the postoprerative period with MD change rate of -0.25 dB/y (P < 0.003), which was slower (P < 0.001) than the preoperative one (-0.70 dB/y). The preoperative mean of total deviation change rate (-0.31 to -1.35 dB/y) improved postoperatively in the superior and inferior paracentral subfields (P < 0.001), whereas it remained unchanged in the inferior cecocentral/arcuate subfields (P > 0.10). The postoperative rate of progression showed no significant variation in these subfields.

CONCLUSIONS

The rate of progression significantly varied among the 6 subfields preoperatively. It was significantly slowed down in the superior subfields by surgical IOP reduction, but not in the inferior cecocentral/arcuate subfields.

Results of long-term monitoring of normal-tension glaucoma patients receiving medical therapy: results of an 18-year follow-up

PURPOSE

To conduct a ≥15-year follow-up assessment of the visual field (VF) in normal-tension glaucoma (NTG) patients receiving medical therapy and to identify risk factors for VF progression.

DESIGN

A retrospective clinical study.

METHODS

Medical records of 78 eyes of 78 NTG patients monitored for ≥15 years were reviewed. VF progression was defined by a mean deviation (MD) deteriorated twice by 3.00 dB from baseline (MD criterion) and an annual decrease in the MD slope exceeding -0.5 dB/year (MD slope criterion). Logistic regression analysis was employed to identify risk factors for VF progression.

RESULTS

The mean follow-up period was 18.3 years. The average intraocular pressure (IOP) before treatment was 15.1 ±1.9 mmHg and the average treated IOP was 13.5 ±1.5 mmHg with 2.0 medications. Forty-two eyes (53.8%) showed VF progression using the MD criterion and 15 eyes (19.2%) showed a negative MD slope less than -0.5 dB/year. Disc hemorrhage (DH) was observed in 30 eyes (38.5%). The mean VF progression rate was -0.38 ±0.30 dB/year in the DH group and -0.24 ±0.28 dB/year in the non-DH group (P = 0.012). Multiple logistic regression analysis identified DH [relative risk (RR) 4.28; P = 0.028] as a risk factor for VF progression using the MD criterion. DH (RR 8.77; P = 0.007) and IOP fluctuation during follow-up (RR 5.03; P = 0.048) were detected as risk factors using the MD slope criterion.

CONCLUSIONS

DH and IOP fluctuation were associated with VF progression in NTG during long-term therapy.

Neuroprotection for treatment of glaucoma in adults

BACKGROUND

Glaucoma is a heterogeneous group of conditions involving progressive damage to the optic nerve, deterioration of retinal ganglion cells and ultimately visual field loss. It is a leading cause of blindness worldwide. Open angle glaucoma (OAG), the commonest form of glaucoma, is a chronic condition that may or may not present with increased intraocular pressure (IOP). Neuroprotection for glaucoma refers to any intervention intended to prevent optic nerve damage or cell death.

OBJECTIVES

The objective of this review was to systematically examine the evidence regarding the effectiveness of neuroprotective agents for slowing the progression of OAG in adults.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 9), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE, (January 1950 to October 2012), EMBASE (January 1980 to October 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to October 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 16 October 2012.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) in which topical or oral treatments were used for neuroprotection in adults with OAG. Minimum follow up time was four years.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed titles and abstracts from the literature searches. Full-text copies of potentially relevant studies were obtained and re-evaluated for inclusion. Two review authors independently extracted data related study characteristics, risk of bias, and outcome data. One trial was identified for this review, thus we performed no meta-analysis. Two studies comparing memantine to placebo are currently awaiting classification until additional study details are provided. We documented reasons for excluding studies from the review.

MAIN RESULTS

We included one multi-center RCT of adults with low-pressure glaucoma (Low-pressure Glaucoma Treatment Study, LoGTS) conducted in the USA. The primary outcome was visual field progression after four years of treatment with either brimonidine or timolol. Of the 190 adults enrolled in the study, 12 (6.3%) were excluded after randomization and 77 (40.5%) did not complete four years of follow up. The rate of attrition was unbalanced between groups with more participants dropping out of the brimonidine group (55%) than the timolol group (29%). Of those remaining in the study at four years, participants assigned to brimonidine showed less visual field progression than participants assigned to timolol (5/45 participants in the brimonidine group compared with 18/56 participants in the timolol group). Since no information was available for the 12 participants excluded from the study, or the 77 participants who dropped out of the study, we cannot draw any conclusions from these results as the participants for whom data are missing may or may not have progressed. The mean IOP was similar in both groups at the four-year follow up among those for whom data were available: 14.2 mmHg (standard deviation (SD) = 1.9) among the 43 participants in the brimonidine group and 14.0 mmHg (SD = 2.6) among the 48 participants in the timolol group. Among the participants who developed progressive visual field loss, IOP reduction of 20% or greater was not significantly different between groups: 4/9 participants in the brimonidine group and 12/31 participants in the timolol group. The study authors did not report data for visual acuity or vertical cup-disc ratio. The most frequent adverse event was ocular allergy to study drug, which occurred more frequently in the brimonidine group (20/99 participants) than the timolol group (3/79 participants).

AUTHORS' CONCLUSIONS

Although neuroprotective agents are intended to act as pharmacological antagonists to prevent cell death, this trial did not provide evidence that they are effective in preventing retinal ganglion cell death, and thus preserving vision in people with OAG. Further clinical research is needed to determine whether neuroprotective agents may be beneficial for individuals with OAG. Such research should focus outcomes important to patients, such as preservation of vision, and how these outcomes relate to cell death and optic nerve damage. Since OAG is a chronic, progressive disease with variability in symptoms, RCTs designed to measure the effectiveness of neuroprotective agents would require long-term follow up (more than four years) in order to detect clinically meaningful effects.

Retrobulbar hemodynamic effects of nipradilol in normal and normal-tension glaucoma eyes

Purpose. To investigate the effects of nipradilol on retrobulbar hemodynamics. Methods. We investigated normal and normal-tension glaucoma (NTG) eyes. Topical nipradilol (one eye) and placebo eye drops (fellow eye) were instilled for 1 week in volunteers. Nipradilol was also instilled in NTG patients. Ultrasound color Doppler imaging for the posterior vessels was performed before, 2 hr, 1 week (for normal), and at 4 weeks (for NTG). Results. In normal eyes, there were significant decreases in the resistance index (RI) for the temporal short posterior ciliary arteries (PCA) at 2 hr and for the ophthalmic arteries at 1 week. There were no significant changes in the placebo-treated eyes. In the NTG eyes, there was a significant decrease in the RI for the central retinal artery, nasal, and temporal PCA at 2 hr and 4 weeks. Conclusion. Short-term observations found that nipradilol increased the ocular blood flow in normal and NTG eyes.