Predicting Risk of Motor Vehicle Collisions in Patients with Glaucoma: A Longitudinal Study

Timolol-loaded ethosomes for ophthalmic delivery: Reduction of high intraocular pressure in vivo

The beta-adrenoceptor blocker timolol maleate (TML) is a commonly used pharmaceutical agent for the management of glaucoma. Conventional eye drops have limitations due to biological or pharmaceutical factors. Therefore, TML-loaded ethosomes have been designed to mitigate these restrictions and give a viable solution for reducing elevated intraocular pressure (IOP). The ethosomes were prepared using the thin film hydration method. Integrating the Box-Behnken experimental strategy, the optimal formulation was identified. The physicochemical characterization studies were performed on the optimal formulation. Then, in vitro release and ex vivo permeation studies were conducted. The irritation assessment was also carried out with Hen's Egg Test-Chorioallantoic Membrane model (HET-CAM), and in vivo evaluation of the IOP lowering effect was also performed on rats. The physicochemical characterization studies demonstrated that the components of the formulation were compatible with each other. The particle size, zeta potential, and encapsulation efficiency (EE%) were found as 88.23 ± 1.25 nm, -28.7 ± 2.03 mV, and 89.73 ± 0.42 %, respectively. The in vitro drug release mechanism was found as Korsmeyer-Peppas kinetics (R²=0.9923). The HET-CAM findings verified the formulation's eligibility for biological applications. The IOP measurements revealed no statistical difference (p>0.05) between the once-a-day application of the optimal formulation and the three-times-a-day application of the conventional eye drop. A similar pharmacological response was observed at lowered application frequencies. Therefore, it was concluded that the novel TML-loaded ethosomes could be a safe and efficient alternative for glaucoma treatment.

Vision rehabilitation in glaucoma patients

PURPOSE OF REVIEW

Vision rehabilitation services are important but underutilized resources for patients with glaucoma. Glaucoma and its impact on vision can affect patients' abilities to read and drive, two activities of daily living that are associated with quality of life and functional independence. In this review, we provide an overview of low vision, discuss barriers to vision rehabilitation, and outline various strategies and interventions to optimize visual function and quality of life in patients with glaucoma.

RECENT FINDINGS

Studies have shown that glaucoma negatively impacts reading, driving and overall quality of life. Decreased visual acuity, visual field loss and reduced contrast sensitivity play a role. Low vision services and interventions can help patients maximize visual function and improve their quality of life. Barriers to receiving these services exist at multiple levels and an increased awareness and integration into routine ophthalmic care are needed to deliver comprehensive care.

SUMMARY

Glaucoma is one of the leading causes of low vision. Ophthalmologists who treat glaucoma often tend to focus on objective measures to monitor progression and disease severity, but the functional impact of glaucoma should also be addressed. Low vision services can benefit patients, particularly for reading and driving, and should be considered as an essential component of patient care.

Glaucoma and Driving License: How to Identify Patients at Risk of Revocation

Aim

To identify clinical criteria that are easily achievable with follow-up tests and can identify subjects not suitable for driving.

Patients and methods

We recruited 194 subjects with a clear diagnosis of glaucoma, with no other conditions that could affect the visual field (VF), and who performed a reliable VF examination. All patients underwent a full ophthalmologic evaluation and a questionnaire considering driving habits. An integrated visual field (IVF) was built using both monocular VF charts; the number of missed points (NoMP) within the central 20°, the average sensitivity (AS), and the better eye mean deviation (BEMD) were evaluated.

Results

A total of 128 subjects showed a valid driving license (DL); 61.7% of drivers did not show missed points within the central 20° of the IVF, 27.4% presented one to three missed points, and 10.9% had four or more missed points. Best corrected visual acuity (BCVA) was highly above the legal criteria.

Stratifying drivers by their BEMD (−7, −10, and −14 dB), we confirmed that the BEMD decrease corresponds to an increased NoMP and a decreased AS.

Conclusion

Better eye mean deviation can be useful in clinical practice to identify patients at increased risk of being unsuitable for driving. Nevertheless, it is important to set specific cut-offs based on on-road driving performance. IVF evaluation may also be implemented in perimeter analysis software so that the composition of IVF, the BEMD, and the AS could directly describe the patient's binocular VF, excluding recourse to the Esterman visual field test (EVFT).

Clinical significance

This new methodology will allow every physician—not just ophthalmologists—even if not an expert in evaluating a VF test, in assessing the ability to drive of glaucomatous patients.

How to cite this article

Landini L, Donati S, Digiuni M, et al. Glaucoma and Driving License: How to Identify Patients at Risk of Revocation. J Curr Glaucoma Pract 2022;16(2):117-123.

Interventions to Improve Reading Performance in Glaucoma

PURPOSE

To evaluate whether changes to contrast, line spacing, or font size can improve reading performance in patients with glaucoma.

DESIGN

Cross-sectional study.

PARTICIPANTS

Thirty-five patients with glaucoma and 32 healthy control participants.

METHODS

A comprehensive ophthalmologic examination was performed followed by reading speed assessment using the Minnesota Low Vision Reading (MNREAD) test under a range of contrasts (10%, 20%, 30%, 40%, and 50%), line spacings (1.0, 1.5, 2.0, 2.5, and 3.0 lines), and font sizes (0.8, 0.9, 1.0, 1.1, and 1.2 logarithm of the minimum angle of resolution), for a total of 15 tests. Regression analyses were performed to examine the effect of varying test conditions on reading speed (measured in words per minute [wpm]).

RESULTS

Participants' mean age was 63.0 ± 12.6 years. Patients with glaucoma showed a visual field mean deviation in the better eye of -6.29 ± 6.35 dB. Reading speeds were significantly slower in patients with glaucoma versus control participants for 14 of the 15 MNREAD tests, despite no significant differences in age, gender, or education between groups. Increased contrast (from 10% to 50%) was associated with faster reading speed in patients with glaucoma (10.6-wpm increase per 10% increase in contrast; 95% confidence interval, 7.4-13.8 wpm; P < 0.001; R² = 0.211). No significant improvement was found in reading speed with increase in font size or line spacing.

CONCLUSIONS

Patients with glaucoma showed significantly slower reading speeds than similarly aged control participants. Reading speed was improved by increasing contrast, but not by increases in line spacing or font size.

Impact of the Support, Educate, Empower Personalized Glaucoma Coaching Program Pilot Study on Eye Drop Instillation Technique and Self-Efficacy

PURPOSE

To assess the Support, Educate, Empower (SEE) personalized glaucoma coaching program impact on (1) eye drop instillation technique and (2) eye drop instillation self-efficacy.

DESIGN

Prospective pre-post pilot study.

PARTICIPANTS

Patients with a diagnosis of glaucoma or ocular hypertension taking ≥1 glaucoma medication, ≥40 years old, spoke English, self-administered their eye drops, and ≤80% adherent to their glaucoma medication by electronic monitoring.

METHODS

Eye drop administration was video recorded before the first SEE in-person coaching session, which included teaching eye drop instillation techniques using a motivational interviewing-based approach. At the third and final in-person counseling session 6 months later, eye drop administration was video recorded. Participants' self-efficacy was assessed using the validated Eye Drop Technique Self-Efficacy Scale (EDTSES) survey at baseline and 1 month after completion of the program. Before and after intervention videos were assessed by an observer masked to time point. Before versus after intervention comparisons were made using McNemar's and paired t tests.

MAIN OUTCOME MEASURES

The main outcome was change in participants' eye drop instillation technique as measured by (1) accuracy of an eye drop landing on the eye, (2) ability to instill an eye drop on the first attempt, and (3) contaminating the bottle by contact with ocular surface, eyelashes, and skin. The secondary outcome measure was before versus after change in the EDTSES score (6 items, each assessed on a 3-point Likert scale, with higher scores indicating better self-efficacy).

RESULTS

Thirty-nine participants completed the SEE intervention, 38 with before and after EDTSES scores and 31 with video recordings. Six of 31 participants instilling drops outside the eye before intervention improved their technique after intervention, whereas 2 participants worsened (P = 0.157). From before to after intervention, participants demonstrated significant improvement in not touching the ocular surface (P = 0.046), the eyelashes (P = 0.020), or the skin (P = 0.025) with the bottle tip. A significant increase was found in eye drop instillation self-efficacy from an average score of 2.6 (standard deviation [SD], 0.3) to 2.8 (SD, 0.2) on the EDTSES score (P = 0.007).

CONCLUSIONS

The SEE program significantly decreased eye drop bottle contamination, increased eye drop instillation self-efficacy, and demonstrated an insignificant increase in ability to instill drops successfully and accurately.

Effects of driver compensatory behaviour on risks of critical pedestrian collisions under simulated visual field defects

Compensatory behaviour is regarded as a helpful strategy to mediate drivers’ deteriorated hazard perception ability due to visual field defects. However, helpfulness of compensatory behaviour for drivers with advanced visual field defects has largely unexplored. This study aims to clarify the effectiveness and limitation of compensatory head movements in critical situations where included pedestrians stepping off a sidewalk under the simulation of advanced visual defects. 18 healthy-sighted drivers participated the data collection that was conducted in a driving simulator under three driving conditions: (1) without visual impairment, (2) with visual impairment and not performing active compensation, and (3) with visual impairment but performing active compensation. The result showed that active compensation led quick accelerator and brake response times, reducing the risk and number of pedestrian collisions. The active compensation led a decrease in the number of non-responses to hazardous pedestrians compared to while driving not performing compensation. However, the compensation could not reduce the number of pedestrian collisions to those of healthy-sighted drivers. Compensatory viewing behaviour contributed to improved driving performance as well as has limits to lead driving performance like healthy-sighted drivers. Developing driver assistance systems and practical compensatory strategies concerning the degrees of impairment and traffic conditions may provide opportunities to improve driving safety deteriorated hazard perception for visually impaired drivers.

Mapping the knowledge domain of road safety studies: A scientometric analysis

As a way of obtaining a visual expression of knowledge, mapping knowledge domain (MKD) provides a vision-based analytic approach to scientometric analysis which can be used to reveal an academic community, the structure of its networks, and the dynamic development of a discipline. This study, based on the Science Citation Index Expanded (SCIE) and Social Sciences Citation Index (SSCI) articles on road safety, employs the bibliometric tools VOSviewer and CitNetExplorer to create maps of author co-citation, document co-citation, citation networks, analyze the core authors and classic documents supporting road safety studies and show the citation context and development of such studies. It shows that road safety studies clustered mainly into four groups, whose we will refer to as "effects of driving psychology and behavior on road safety", "causation, frequency and injury severity analysis of road crashes", "epidemiology, assessment and prevention of road traffic injury", and "effects of driver risk factors on driver performance and road safety", respectively. Through our analysis, the core publications and their citation relationships were quickly located and explored, and "crash frequency modeling analysis" has been identified to be the core research topic in road safety studies, with spatial statistical analysis technique emerging as a frontier of this topic.

The Impact of Visual Field Loss on Driving Skills: A Systematic Narrative Review

Purpose

To review the evidence on the impact of visual field loss on skills required for driving.

Methods

A literature search was undertaken using a systematic approach. Papers within scope were identified by two independent reviewers, and papers were grouped into similar themes for discussion.

Key findings

Evidence suggests that both binocular and monocular visual field defects have a negative impact on driving skills. Both central and peripheral cause difficulties, but the degree of impact is dependent on the defect severity and compensation ability. Many factors that affect compensation to visual field loss and the effects of visual field loss on driving skills are discussed, including cognitive status, age and duration of visual field loss. In summary, in central visual field loss compensation, strategies include reduction of overall driving speed; whereas, in peripheral field loss, increased scanning is reported to aid adaptation.

Conclusions

For driving, there is evidence that complete and/or binocular visual field loss poses more of a difficulty than partial and/or monocular loss, and central defects cause more problems than peripheral defects. A lack of evidence exists concerning the impact of superior versus inferior defects. The level of peripheral vision loss that is incompatible with safe driving remains unknown, as compensation abilities vary widely between individuals. This review highlights a lack of evidence in relation to the impact of visual field loss on driving skills. Further research is required to strengthen the evidence to allow clinicians to better support people with visual field loss with driving advice.

Mobile Telephone Use and Reaction Time in Drivers With Glaucoma

IMPORTANCE

Combining mobile telephone use with driving is not unusual. However, distracted driving limits driving performance because of limited capacity for persons to divide attention.

OBJECTIVES

To investigate the frequency of mobile telephone use while driving and to assess whether patients with glaucoma had a disproportionate decrease in driving performance while conversing on a mobile telephone compared with healthy participants.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional study of surveys collected from 112 patients with glaucoma and 70 control participants investigating mobile telephone use while driving. A randomly selected subgroup of 37 patients with glaucoma and 28 controls drove in a driving simulator to investigate peripheral event detection performance during distracted driving at the Visual Performance Laboratory, Duke University, Durham, North Carolina. Data collection was performed from December 1, 2016, through April 30, 2017.

EXPOSURES

Participants answered a survey and submitted to a driving simulation test with and without mobile telephone use.

MAIN OUTCOMES AND MEASURES

Survey answers were collected, and distracted driving performance, assessed by reaction time to peripheral stimuli, was analyzed.

RESULTS

Of the 182 participants who answered the survey, the 112 participants with glaucoma included 56 women (50.0%) and had a mean (SD) age of 73.6 (9.6) years. The 70 controls included 49 women (70.0%) and had a mean (SD) age of 68.4 (10.9) years. When asked about mobile telephone use while driving, 30 patients with glaucoma (26.8%) admitted rarely using and 2 (1.8%) sometimes using it. In the control group, 20 participants (28.6%) admitted rarely using and 2 (2.9%) sometimes using the telephone while driving (P = .80). Reaction times to peripheral stimuli were significantly longer among patients with glaucoma compared with controls during mobile telephone use (median [interquartile range], 1.86 [1.42-2.29] seconds vs 1.14 [0.98-1.59] seconds; P = .02). Compared with driving performance while not using a mobile telephone, the mean (SD) increase of 0.85 (0.60) second in reaction time while conversing on the mobile telephone among patients with glaucoma was significantly greater than the mean (SD) increase of 0.68 (0.83) second for controls (P = .03).

CONCLUSIONS AND RELEVANCE

This study's findings indicate that patients with glaucoma use mobile telephones while driving as frequently as healthy participants. However, the findings also suggest that patients with glaucoma may experience a greater decline than healthy participants in their ability to detect peripheral events while driving when also talking on a mobile telephone. Patients with glaucoma should be informed that they may have a higher driving risk that may be worsened by distractions, such as mobile telephone use.

Performance-based visual field testing for drivers with glaucoma: A pilot study

OBJECTIVE

Conventional visual field (VF) tests are limited in predicting on-road driving performance of individuals with glaucoma. We developed a new performance-based VF test in a driving simulator for individuals with glaucoma. The aim was to evaluate the psychometric properties of the newly developed test.

METHODS

In this pilot study, 17 drivers with glaucoma aged 65.24 ± 9.69 and 13 control drivers aged 61.27 ± 11.45 completed the performance-based VF task. Construct validity was determined by comparing performance on the new task with results on conventional visual and perimetry tests including Humphrey Visual Field Analyzer, Keystone Vision Screener, and Useful Field of View (UFOV). Concurrent validity was evaluated by comparing performance on the new task with on-road driving performance, scored using the Test Ride for Investigating Practical fitness-to-drive (TRIP). Ten individuals (7 with glaucoma and 3 controls) participated in the test-retest reliability assessment.

RESULTS

Drivers with glaucoma identified fewer symbols (P = .047) and took longer to respond to the symbols (P = .048) compared to controls. In the glaucoma group, correct responses on the performance-based VF test correlated strongly (r = -0.51, P = .046) with UFOV divided attention. Both glaucoma and control groups achieved submaximal to maximal scores on the TRIP (median [Q1-Q3], glaucoma: 193 [191-196]; controls: 196 [195-196]; P = .16). No strong correlations were found between scores on the performance-based VF test and on-road driving performance in glaucoma. The intraclass correlation coefficients ranged between 0.77 for response time and 0.92 for correct responses, indicating good to excellent test-retest reliability.

CONCLUSIONS

We established the construct validity and test-retest reliability of the performance-based VF test. Future studies should include a larger sample with more severe driving difficulties to demonstrate the concurrent validity between performance-based VF testing and on-road driving performance in glaucoma.

Agreement of driving simulator and on-road driving performance in patients with binocular visual field loss

PURPOSE

On-road testing is considered the standard for assessment of driving performance; however, it lacks standardization. In contrast, driving simulators provide controlled experimental settings in a virtual reality environment. This study compares both testing conditions in patients with binocular visual field defects due to bilateral glaucomatous optic neuropathy or due to retro-chiasmal visual pathway lesions.

METHODS

Ten glaucoma patients (PG), ten patients with homonymous visual field defects (PH), and 20 age- and gender-matched ophthalmologically normal control subjects (CG and CH, respectively) participated in a 40-min on-road driving task using a dual brake vehicle. A subset of this sample (8 PG, 8 PH, 8 CG, and 7 CH) underwent a subsequent driving simulator test of similar duration. For both settings, pass/fail rates were assessed by a masked driving instructor.

RESULTS

For on-road driving, hemianopia patients (PH) and glaucoma patients (PG) showed worse performance than their controls (CH and CG groups): PH 40%, CH 30%, PG 60%, CG 0%, failure rate. Similar results were obtained for the driving simulator test: PH 50%, CH 29%, PG 38%, CG 0%, failure rate. Twenty-four out of 31 participants (77%) showed concordant results with regard to pass/fail under both test conditions (p > 0.05; McNemar test).

CONCLUSIONS

Driving simulator testing leads to results comparable to on-road driving, in terms of pass/fail rates in subjects with binocular (glaucomatous or retro-chiasmal lesion-induced) visual field defects. Driving simulator testing seems to be a well-standardized method, appropriate for assessment of driving performance in individuals with binocular visual field loss.

Glaucoma and quality of life: fall and driving risk

PURPOSE OF REVIEW

Numerous population-based studies suggest that glaucoma is an independent risk factor for falling and motor vehicle collisions, particularly for older adults. These adverse events lead to increased healthcare expenditures and decreased quality of life. Current research priorities, therefore, include identifying factors that predispose glaucoma patients to falling and unsafe driving, and developing screening strategies and targeted rehabilitation. The purpose of this article is to review recent studies that address these priorities.

RECENT FINDINGS

Studies continue to support that glaucoma patients, particularly those with advanced disease, have an increased risk of falling or unsafe driving. Risk factors, however, remain variable and include severity and location of visual field defects, contrast sensitivity, and performance on divided attention tasks. Such variability is likely because of the multifactorial nature of ambulating and driving and compensatory strategies used by patients.

SUMMARY

Falls and unsafe driving remain a serious public health issue for older adults with glaucoma. Ambulation and driving are complex tasks and there is no consensus yet, regarding the best methods for risk stratification and targeted interventions to increase safety. Therefore, comprehensive and individualized assessments are recommended to most effectively evaluate a patient's risk for falling or unsafe driving.

Effect of Cognitive Demand on Functional Visual Field Performance in Senior Drivers with Glaucoma

Purpose: To investigate the effect of cognitive demand on functional visual field performance in drivers with glaucoma.

Method: This study included 20 drivers with open-angle glaucoma and 13 age- and sex-matched controls. Visual field performance was evaluated under different degrees of cognitive demand: a static visual field condition (C1), dynamic visual field condition (C2), and dynamic visual field condition with active driving (C3) using an interactive, desktop driving simulator. The number of correct responses (accuracy) and response times on the visual field task were compared between groups and between conditions using Kruskal–Wallis tests. General linear models were employed to compare cognitive workload, recorded in real-time through pupillometry, between groups and conditions.

Results: Adding cognitive demand (C2 and C3) to the static visual field test (C1) adversely affected accuracy and response times, in both groups (p < 0.05). However, drivers with glaucoma performed worse than did control drivers when the static condition changed to a dynamic condition [C2 vs. C1 accuracy; glaucoma: median difference (Q1–Q3) 3 (2–6.50) vs. controls: 2 (0.50–2.50); p = 0.05] and to a dynamic condition with active driving [C3 vs. C1 accuracy; glaucoma: 2 (2–6) vs. controls: 1 (0.50–2); p = 0.02]. Overall, drivers with glaucoma exhibited greater cognitive workload than controls (p = 0.02).

Conclusion: Cognitive demand disproportionately affects functional visual field performance in drivers with glaucoma. Our results may inform the development of a performance-based visual field test for drivers with glaucoma.

Predicting Future Self-Reported Motor Vehicle Collisions in Subjects with Primary Open-Angle Glaucoma Using the Penalized Support Vector Machine Method

PURPOSE

We predict the likelihood of a future motor vehicle collision (MVC) from visual function data, attitudes to driving, and past MVC history using the penalized support vector machine (pSVM) in subjects with primary open-angle glaucoma (POAG).

METHODS

Patients with POAG were screened prospectively for eligibility and 185 were analyzed in this study. Self-reported MVCs of all participants were recorded for 3 years from the baseline using a survey questionnaire every 12 months. A binocular integrated visual field (IVF) was calculated for each patient by merging a patient's monocular Humphrey Field Analyzer (HFA) visual fields (VFs). The IVF was divided into six regions, based on eccentricity and the right or left hemifield, and the average of the total deviation (TD) values in each of these six areas was calculated. Then, the future MVCs were predicted using various variables, including age, sex, 63 variables of 52 TD values, mean of the TD values, visual acuities (VAs), six sector average TDs with (pred_{penSVM_all}) and without (pred_{penSVM_basic}) the attitudes in driving, and also past MVC history, using the pSVM method, applying the leave-one-out cross validation.

RESULTS

The relationship between pred_{penSVM_basic} and the future MVC approached significance (odds ratio = 1.15, [0.99-1.29], P = 0.064, logistic regression). A significant relationship was observed between pred_{penSVM_all} and the future MVC (odds ratio = 1.21, P = 0.0015).

CONCLUSIONS

It was useful to predict future MVCs in patients with POAG using visual function metrics, patients' attitudes to driving, and past MVC history, using the pSVM.

TRANSLATIONAL RELEVANCE

Careful consideration is needed when predicting future MVCs in POAG patients using visual function, and without driving attitude and MVC history.

Risk Factors for Motor Vehicle Collisions in Patients with Primary Open-Angle Glaucoma: A Multicenter Prospective Cohort Study

Purpose

To identify the incidence rate of motor vehicle collisions (MVCs) in patients with no ocular pathology other than primary open-angle glaucoma (POAG) and determine the putative risk factors for MVCs in this group of patients.

Methods

We designed a prospective cohort study across three centers utilizing a consecutive sampling method to identify all patients with POAG between the ages of 40 and 80 years old. Patients with glaucoma were consecutively screened for eligibility. All study participants answered a questionnaire about motor vehicle collisions at baseline, and answered the questionnaire again every 12 months (± 1 month) after baseline for three years. A binocular integrated visual field was calculated for each patient by merging a patient’s monocular Humphrey Field Analyzer (HFA) visual fields (VFs), using the ‘best sensitivity’ method. Patients with incident MVCs were defined as the “MVC+” group and patients without incident MVCs were defined as the “MVC-" group. Adjusted odds ratios for the incidence of MVCs were estimated with a logistic regression model.

Results

One hundred and ninety-one Japanese POAG patients were analyzed in this study. The age of the participants was 63.7 ± 10.2 [mean ± standard deviation]. A total of 28 participants experienced a MVC during the follow up period of three years (4.9% per year). Ten patients (5.2%) experienced a MVC in the first year, 13 patients (6.8%) in the second year, and 11 patients (5.8%) in the third year (some patients experienced multiple MVCs over different years). Best corrected visual acuity in the worst eye was significantly worse in the MVC+ group (0.03 ± 0.01, mean ± standard deviation, LogMar) compared with the MVC- group (0.01 ± 0.003, p = 0.01), and was the only variable identified as a significant predictor of future MVCs in the multiple logistic regression model [odds ratio: 1.2, 95% confidence interval (CI): 1.1 to 1.4].

Conclusion

Deterioration in visual acuity in the worst eye is a risk factor for future MVCs in patients with POAG.

Primary open-angle glaucoma

Glaucoma is an optic neuropathy that is characterized by the progressive degeneration of the optic nerve, leading to visual impairment. Glaucoma is the main cause of irreversible blindness worldwide, but typically remains asymptomatic until very severe. Open-angle glaucoma comprises the majority of cases in the United States and western Europe, of which, primary open-angle glaucoma (POAG) is the most common type. By contrast, in China and other Asian countries, angle-closure glaucoma is highly prevalent. These two types of glaucoma are characterized based on the anatomic configuration of the aqueous humour outflow pathway. The pathophysiology of POAG is not well understood, but it is an optic neuropathy that is thought to be associated with intraocular pressure (IOP)-related damage to the optic nerve head and resultant loss of retinal ganglion cells (RGCs). POAG is generally diagnosed during routine eye examination, which includes fundoscopic evaluation and visual field assessment (using perimetry). An increase in IOP, measured by tonometry, is not essential for diagnosis. Management of POAG includes topical drug therapies and surgery to reduce IOP, although new therapies targeting neuroprotection of RGCs and axonal regeneration are under development.

What rates of glaucoma progression are clinically significant?

Clinically important rates of glaucoma progression (worsening) are ones that put a patient at risk of future functional impairment or reduction of vision-related quality of life. Rates of progression can be evaluated through measuring structural or functional changes of the optic nerve. Most treated eyes do not progress at rates that will lead to future visual impairment, but there are a significant proportion (3-17%) of eyes, that are at risk of impairment even under clinical care. While very fast rates of progression (e.g. MD progression of -1.5 dB/year) are generally problematic, much slower rates also may be deleterious for young patients, particularly those diagnosed with late disease. As a result, it is important to consider life expectancy, disease severity and vision-related quality of life based treatment targets to estimate future prognosis when evaluating whether a rate of glaucoma progression can be clinically relevant.