Telemedicine for Glaucoma: Guidelines and Recommendations

Background

Glaucoma is the leading cause of irreversible blindness worldwide, estimated to affect >60 million people.¹ This condition is clinically defined as a group of progressive optic neuropathies having characteristic patterns of visual field loss. In the United States, the prevalence of glaucoma ranges from 2% among those aged 40–49 years and increases with age to 8% or more among those aged 80 years or older.² The estimated yearly direct cost for glaucoma management in the United States exceeds $2.9 billion.³

Current diagnostic and treatment guidelines for glaucoma are informed by several large multicenter clinical trials.^4,5 Glaucoma care guidelines are not as standardized as those for diabetic retinopathy (DR), which allow for significant regional and provider variability in glaucoma diagnosis and management.⁵ It is important to note that other areas of medicine—including psychiatry and primary care—have flexible practice guidelines, which have not been a barrier to the successful large-scale uptake of telemedicine in these fields.

Introduction

Teleglaucoma is a growing field with great promise for increasing patient access to high-quality cost-effective glaucoma care by leveraging new telecommunications and diagnostic technologies. Many of the telehealth principles underlying teleglaucoma programs are shared with those in teleretinal programs for DR. In this study, we review some additional considerations and practice recommendations for teleglaucoma programs.

Discussion

Definition and Literature Review

Glaucoma is a chronic lifelong disease for which patients are monitored at clinic visits occurring one or more times yearly. Access to glaucoma specialists is becoming more limited as the prevalence of glaucoma is expected to increase dramatically with our aging populations.^1,6 Advances in telecommunications and diagnostic technologies have allowed for the development of teleglaucoma programs, wherein key glaucoma measures are collected from a patient at an originating site and then transmitted to a distant site provider for interpretation. Teleglaucoma has the potential to increase access to glaucoma care by improving efficiency and decreasing the need for long-distance travel for patients.⁷ There is an emerging body of literature to support teleglaucoma programs.^8–22 In addition to these published reports, there are also many active clinical teleglaucoma programs.

Kotecha et al. reported using teleglaucoma to decrease the amount of time patients spent during each clinic visit.²³ Another study found that approximately three-quarters of glaucoma suspects evaluated remotely did not require in-person follow-up examination.²¹ A cost-effectiveness analysis found that teleglaucoma was more cost-effective than in-person examination for glaucoma screening.²⁴ Patients participating in teleglaucoma programs report comparable satisfaction with in-person examinations.²⁵ A number of teleretinal programs have published high rates of incidental detection of glaucomatous-appearing optic nerves, and suspected glaucoma is a major contributor to clinical referrals in teleretinal diabetic screening.^26,27

Types of Teleglaucoma Programs

The extent to which a given teleglaucoma program can support various types of use cases depends greatly on the resources available as well as the training and comfort level of the providers. We define a “Full Scope” teleglaucoma program as one with sufficient resources to provide not only glaucoma screening but also diagnosis and treatment monitoring. The types of teleglaucoma programs can be described on the following spectrum of use cases:

Screening

Screening for glaucoma refers to the systematic evaluation of asymptomatic persons for evidence of glaucomatous damage.²⁸ In 2013, the United States Preventative Services Task Force concluded “the current evidence is insufficient to assess the balance of benefits and harms of screening for primary open-angle glaucoma in adults.”²⁹ However, subsequent studies have suggested that screening in populations at high risk for glaucoma is effective.^30,31 A systematic review of teleglaucoma screening estimated its sensitivity as 83.2% and specificity as 79.0%.²⁸

Diagnostic consultation

Teleglaucoma can also be used to provide specialist consultation from a distance to reduce patient travel.^21,32 Verma and coauthors reported that 69% of teleglaucoma patients referred for suspected glaucoma could be managed by the referring primary eye care provider and did not require in-person evaluation by a specialist.²¹

Long-term treatment monitoring

Teleglaucoma can also be used for follow-up monitoring after initiation of treatment. “Virtual Glaucoma Clinics” described in the United Kingdom use teleglaucoma for long-term treatment monitoring.^9,22,23 In these clinics, “stable” patients are followed through virtual review of glaucoma testing with in-person visits only when necessary.²³ Kashiwagi et al. have described a slit-lamp camera system to accurately monitor delegation of postoperative care to nonglaucoma specialists after glaucoma surgery.³³

Key Components of Teleglaucoma Programs

Additional key components in establishing teleglaucoma programs include the following:

Patient history

Important components of the patient history include any ocular and visual symptoms, demographics, ocular history (including the use of any eye medications, last eye examination and recommended follow-up, and previous diagnosis of DR), medical history, and family history (e.g., first-degree relatives with glaucoma and the severity of their disease).

Equipment

Equipment needs for each teleglaucoma program depend on the program’s goals, provider preferences, patient population, and the availability of community resources. Some important components may include:

1.	Visual acuity testing.
2.	Visual fields. Reliable visual field testing is required for (1) establishing baseline visual fields for future comparisons and (2) detecting progressive visual field loss in patients with worsening glaucoma.5 Automated static threshold perimetry with white-on-white stimuli is considered the gold standard for diagnosis and monitoring of glaucoma.5 The Swedish interactive thresholding algorithm is a commonly used testing algorithm. Frequency-doubling technology and short-wavelength automated perimetry may be useful in detecting early disease, and their use in a teleglaucoma program can be considered.34 Two commonly used machines for automated perimetry are the Humphrey Field Analyzer (Carl Zeiss Meditec, Jena, Germany) and the Octopus Perimeter (Haag-Streit, Koniz, Switzerland, Koniz).35. In the future, remote testing using web- or tablet-based programs may be useful.36,37
3.	Intraocular pressure. Multiple devices are available for measuring intraocular pressure. Some devices, such as the iCare tonometer (iCare USA, Raleigh, NC), do not require instillation of a topical anesthetic and may even be used by patients at home (iCare HOME; iCare USA).38,39 Continuous intraocular pressure monitoring systems may play a role in future teleglaucoma programs (SENSIMED Triggerfish contact lens sensor; Sensimed AG, Lausanne, Switzerland).40,41 However, applanation with a topical anesthetic is still considered the gold standard for intraocular pressure measurement.5
4.	Pachymetry. Central corneal thickness has become an important measure for evaluating glaucoma risk and for setting individualized intraocular pressure goals.5,42 Options for measuring central corneal thickness include ultrasound, low-coherence reflectometry, and Scheimpflug photography.43
5.	Anterior chamber imaging/gonioscopy. Devices that image the anterior chamber, such as anterior segment optical coherence tomography (OCT) and Scheimpflug photography, can assist in identifying patients at risk for narrow angle glaucoma, but the precise threshold for treatment with peripheral iridotomy has yet to be widely agreed upon.44 The standard of care for the evaluation of anatomic narrow angles and angle closure glaucoma remains in-person assessment of the angle by a provider using traditional gonioscopy. Remote operating slit-lamp microscopes may play a more important role in the future, as these could allow for improved diagnosis of secondary glaucomas.33
6.	Fundus photography. Fundus photography allows providers to qualitatively assess the optic nerve. The correlation between stereoscopic (three-dimensional) fundus photographs and ophthalmologist optic disk assessment has been well validated.45 Studies suggest that three-dimensional photographs are superior to two-dimensional photographs for glaucoma evaluation.46 However, further research is needed to determine the relative benefits of these two modalities in meeting the clinical needs of teleglaucoma programs. The additional flash photography needed to obtain stereo images may lead to a reduction in the patient’s pupil size and lead to inadequate image quality in nonmydriatic photography.
7.	Retinal nerve fiber layer (RNFL) imaging. The RNFL thickness adjacent to the optic nerve is a commonly used objective measure for monitoring possible glaucoma progression.47 Measurement of the RNFL thickness has also been used for glaucoma screening.48,49 The data are most useful when compared with age-matched controls. However, there are significant artifacts and anomalies that can produce false positive results, particularly in patients with high degrees of nearsightedness.50 Examples of equipment used to measure the RNFL thickness include OCT and Heidelberg retinal tomography.
8.	Additional equipment. Tests for refractive error and color vision may also be helpful.

Software

Clinical decision-making for glaucoma requires the complex synthesis of a variety of measures over time. Thus, it is important for software to enable time-efficient clinical workflows. Several companies offer glaucoma-focused software programs that allow providers to rapidly evaluate multiple components of longitudinal patient data, often viewed concurrently within a single screen (e.g., Zeiss Forum; Carl Zeiss Meditec and Care1 Telemedicine Network, British Columbia, Canada). Artificial intelligence software for image analysis may play a role in the future of teleglaucoma.⁵¹

Personnel

Skilled providers, technical, and administrative staff support are needed for both collecting and reviewing the complex data needed for teleglaucoma programs. The personnel and/or providers at the originating site(s) play an important role in ensuring high-quality data collection, detailed patient history taking, and, in some cases, appropriate patient education and counseling. Counseling topics can range from providing general information about glaucoma diagnosis to detailed discussions regarding medication adherence, the assessment of medication-related side effects, and the risks and benefits of various treatment options. Interdisciplinary collaborations between providers at the originating and distant sites can be beneficial in providing a high level of teleglaucoma care.^21,32

Providers at the distant sites can perform consultations either in real-time or using a store-and-forward model. Either option may be acceptable with sufficiently detailed documentation and instructions communicated to the patient and personnel at the originating site. Personnel involved in administrative and information technology support are often closely linked with the distant/central site. A dedicated program coordinator can be invaluable for ensuring the smooth operation of teleglaucoma programs.

Financial

Start-up and ongoing maintenance costs associated with teleglaucoma programs are generally much higher than those of teleretinal programs due to extensive equipment, software, and personnel requirements already described. A recent systematic review found that the mean reported cost of establishing a teleglaucoma screening program ranged from $89,703 to $123,164.²⁸ Although teleglaucoma screening requires substantial resources, a follow-up study estimated that using telemedicine to screen for glaucoma was more cost-effective than in-person examinations, with predicted savings of $27,460 per quality-adjusted life year.²⁴

Teleglaucoma programs in Canada and Australia have obtained reimbursement.^12,52 Reimbursement to offset technical and personnel costs are important for encouraging sustained utilization of these services.⁵² Further advances in technology may make teleglaucoma programs more affordable in the future.

Implementation

Owing to the high equipment, personnel, and financial start-up costs associated with teleglaucoma, it may be beneficial for providers to implement a collaborative model of care. Some implementation models include:

1.	Traditional telemedicine. A teleglaucoma program purchases all equipment and provides trained personnel for a remote site. This model is the most expensive and is more commonly implemented in teleretinal programs for DR, which may have fewer equipment and training needs.
2.	Collaborative telemedicine. Partnerships are created between providers with access to different types of equipment, levels of glaucoma expertise, and patient access. This model may involve collaborations between various types of providers and can increase the financial feasibility of these programs.
3.	In-house telemedicine. Providers utilize equipment and staff in their own clinic to deliver teleglaucoma care.

Special mention should be made for “Digitally Integrated Visits,” a specific implementation of In-House Telemedicine, wherein glaucoma patients have a subset of clinic visits reserved solely for the purpose of glaucoma testing, such as visual fields, performed by technical personnel without seeing the provider at the same visit. The provider then reviews the test results and may respond by making changes to the patient’s care plan. This system reduces the number of in-person provider visits while ensuring provider oversight of the patient’s care. It is important that the patient and technical personnel have the option to escalate patient care to in-person visits with the provider when requested.

Conclusions

Teleglaucoma has tremendous potential to improve patient access to high-quality cost-effective glaucoma care. We have reviewed some special considerations needed to address the complexity of providing guideline-concordant glaucoma care. A wide spectrum of teleglaucoma implementations is currently used around the world. The growing body of literature and experience from active teleglaucoma programs will continue to inform further development of these programs. We anticipate that teleglaucoma will have an increasingly important public health impact through expanding access to the high-quality care for glaucoma patients worldwide.

Disclosure Statement

K.G. is the Ophthalmology Director of Care 1 Inc.; L.R.P. is a consultant to Verily, Eyenovia, Bausch+Lomb, Nicox and Emerald Bioscience.

Funding Information

Y.L. was funded in part by an institutional grant from Research to Prevent Blindness to the Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, and by National Institutes of Health K23 EY026518.

B.S. is supported in part by an Unrestricted Grant from Research to Prevent Blindness, New York, NY, to the Department of Ophthalmology & Visual Sciences, University of Utah.

L.R.P. was funded in part by a grant from the National Eye Institute.

The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or Research to Prevent Blindness.