Chapter 7: Teleophthalmology

PG is a 56-year-old male with a 17-year history of suboptimally controlled type 2 diabetes mellitus. He has always had good vision and requires only over-the-counter reading glasses. Because of the inconvenience of having his pupils dilated and because he has no vision symptoms, he has not had an eye examination for diabetic retinopathy in more than 7 years. Recently his primary care physician began offering screening evaluations for diabetic retinopathy. At a regularly scheduled primary care follow-up visit, PG elected to have nonmydriatic (with undilated pupils) retinal photographs taken. The images were sent to a remote reading center for evaluation by an ophthalmologist. A report was returned to the primary care physician the next day with a diagnosis of high-risk proliferative diabetic retinopathy in the right eye and severe nonproliferative diabetic retinopathy in the left eye ( Figure 7-1 ). He was immediately referred to a retina specialist and underwent panretinal laser photocoagulation in the right eye within the following 2 weeks. He now understands the severity of his eye disease and regularly returns to his retina specialist for follow-up and management of his diabetic retinopathy.

Without treatment, half of patients with proliferative diabetic retinopathy will lose their vision within 2 years. Individuals treated with panretinal photocoagulation reduce the risk of severe vision loss by 50% compared with untreated patients with the same severity of disease. Clearly having access to telemedicine diabetic retinopathy screening had a significant impact on the likelihood of preserving vision in this patient.

Teleophthalmology allows for the delivery of eye care at a distance using telecommunications technology to transmit information to a remote eye care provider. Teleophthalmology is an excellent example of the alignment of telemedicine with the Triple Aim health policy, a benchmark for health care reform in the United States. ¹ The Triple Aim objectives are to 1) improve the health of populations, 2) improve the patient experience of their care, and 3) reduce per capita cost of health care. Although teleophthalmology is still in the relatively early stages of adoption, there is clear evidence that it is a useful adjunct to traditional face-to-face eye care in achieving the Triple Aim goals. This chapter outlines the current status of teleophthalmology and ocular telehealth, including the common modalities and technologies being used. Validation, quality assurance, reimbursement and practice recommendations, and guidelines for the most common teleophthalmology applications will be discussed.

Telemedicine is mature, technology is no longer a barrier, connectivity is a reality in most geographies, and the benefits are proven and real. Telemedicine can be performed in a synchronous or real-time face-to-face interaction with video technology or more simply with asynchronous store-and-forward technology, which does not require the patient and provider to be present simultaneously. Ophthalmology is a highly visual specialty, and digital imaging devices are used with many eye diseases for diagnosis and intervention. Ophthalmology is therefore ideally suited to take advantage of telemedicine, especially with store-and-forward platforms. With asynchronous modalities of teleophthalmology, images are obtained and transmitted to a reading site either with or without compression. This utilizes much lower bandwidth than synchronous video visits and allows high-resolution images to be delivered to a reading center for evaluation and interpretation, often with the use of image enhancement tools.

Imaging systems are only one of multiple critical components for the efficient operation of a teleophthalmology program.

Ophthalmic imaging encompasses a wide variety of modalities ranging from digital photography to optical coherence tomography (OCT), all of which can be captured and easily transmitted for remote interpretation. Most of the imaging performed for ocular care is noninvasive. The external eye, eyelids, and ocular adnexa can be easily documented with external ocular photography. Off-the-shelf digital cameras now largely have at least 10 to 14 megapixel resolution and provide appropriate color reproduction and resolution for medical imaging of the external eye.

A fundus camera is the optical instrument used to visually document the retina. Excellent automated nonmydriatic fundus cameras, which do not require pupil dilation, are now readily available necessitating only limited training to obtain excellent retinal images. The information derived from retinal images depends on the field of view, which determines the extent of the retina imaged, stereoscopic versus monoscopic views, and color versus monochromatic images. Special-use fundus cameras are also available to provide wide-angle imaging, stereo imaging, and handheld imaging options. Although legacy 30-degree color images of the retina are still widely used in ophthalmology, wide field photography using low-power coherence laser beams to scan the retina enables photographs covering up to 80% or more of the retina in a single high-resolution, 120- to 200-degree image. This becomes a consideration for diseases that include significant peripheral retinal pathology and is even essential for conditions such as retinopathy of prematurity (ROP). Although such improvements in digital imaging systems further enhance the delivery of care by decreasing the unreadable image rate and allowing more efficient access to a larger at-risk population, their cost and size limit the use for telemedicine applications. ^2,3

Imaging the anterior segment of the eye is more complex and requires a slit lamp with a built-in digital camera or an adapter to attach an off-the-shelf camera. Slit lamps offer a variety of illuminating and observing methods and require a skilled operator. The slit lamp evaluation is a dynamic process involving changes in illumination and angle of view. Although significant information can be gleaned from single images, documentation of a complete slit lamp examination requires capturing a video or at least multiple images.

Additional specialty imaging modalities are being explored for use in telemedicine applications, including OCT. OCT uses light-scattering properties of tissue to provide cross-sectional images of the retina's distinctive layers with resolutions greater than 10 µm, allowing mapping and measuring of retinal layers and retinal thickness. These measurements provide diagnostic and treatment guidance for glaucoma and retinal diseases, including age-related macular degeneration and diabetic retinopathy. Although not yet widely used in teleophthalmology applications, partly due to its significant cost, OCT may be more useful for future telemedicine strategies than stereo fundus photographs in the detection of diabetic macular edema or swelling of the central retina, which is one of the two main causes for vision loss in diabetic retinopathy, and for assessing progression of glaucoma.

Numerous smart phone applications for telemedicine have been developed in recent years, including various adapters to allow capture of retinal images. For teleophthalmology screening applications, such as for diabetic retinopathy, to reach their full potential, imaging devices need to be deployed in all primary care settings, including remote and socioeconomically disadvantaged populations. Currently this is not feasible based on retinal imaging devices that cost $10,000 to $50,000 or more. Widely available smart phones with advanced imaging and integrated data transmission capability can be adapted for ophthalmoscopy and retinal photography. ⁴ Such devices are being explored as a low-cost portable solution and have shown clinical potential for screening applications. Early results are encouraging, at present, but validation of effectiveness compared to current established nonportable telemedicine systems is still lacking. ⁵ Additional concerns are that these new technologies are not standardized and have a short product life cycle. Teleophthalmology is an ideal platform to maximize the interaction of ongoing technological innovations with various digital ocular imaging modalities and pharmaceutical advances in response to the increasing demand for eye care and to more effectively prevent vision loss.

Evaluation by remote telemedicine services must prove to be as safe as a traditional, in-person eye evaluation. Effectiveness refers to how well evidence-based practices are followed. The cornerstone of a safe and effective teleophthalmology program is clinical validation. The validation process, which should consider the entire program from image acquisition to data transmission, possible image compression, image review, and reporting, is a comprehensive assessment of the telemedicine system's safety and helps ensure that patients are not harmed by care that is intended to help them. Validation of ocular telehealth programs also provides a measure of the effectiveness of the system and is based on evidence and scientific knowledge.

The continuing relevance of a program's validation can only be ascertained with robust quality assurance. Given the increasing utilization of telemedicine as an alternative means of assessing patients with eye diseases and its realized benefits, efforts must now focus on ensuring that quality of care and long-term outcomes are not compromised with further implementation of large-scale ocular telehealth programs. Health care quality measures are mechanisms used to quantify the quality of a selected aspect of care by comparing it to an evidence-based criterion. Clinical performance measures, on the other hand, are mechanisms to assess the degree to which a provider competently and safely delivers appropriate clinical services to the patient in a timely manner. Together these domains of quality measures encompass the six aims outlined by the Institute of Medicine that a health care system must fulfill to provide quality health care: namely that health care should be safe, effective, patient centered, timely, efficient, and equitable. ⁶ The six aims are complementary, integrally connected with each other, and synergistic. Telemedicine health care delivery methods and ocular telehealth programs can be assessed in each of these dimensions through various performance indicators and quality measures, which must be specific, quantifiable, achievable, realistic, time bound, evidence based, and tailored to each program's objectives.

In ophthalmology, most telemedicine applications involve imaging in settings outside the traditional eye care arena, such as primary care venues for diabetic retinopathy screening and neonatal intensive care units for ROP screening. The majority of teleophthalmology services concentrate on screening and determining the need for referral for expert care. A literature review of over 2,000 publications on teleophthalmology or ocular telehealth revealed that more than one-third of the literature is on diabetic retinopathy screening. ⁷ Telemedicine for general ophthalmology, ROP, and glaucoma comprised the bulk of the remaining publications. Additionally, more than 80% of the teleophthalmology projects described utilized store-and-forward technology.

It is estimated that by the year 2040, globally there will be 642 million persons with diabetes mellitus, and half of this population will develop diabetic retinopathy. ⁸ Despite recent advances in diagnostic capabilities and the availability of highly effective evidence-based treatment options, vision loss from complications of diabetic retinopathy remains the leading cause of legal blindness in working-age adults in most Western societies. ⁹ This is due to multiple factors, including that early stages of disease are asymptomatic and patients are unaware of the need for screening, poor access to care, and patient inconvenience. ¹⁰ As a result only about half of all patients with diabetes mellitus undergo annual retinal examinations as is recommended by widely accepted guidelines. ¹¹ Appropriate screening and timely treatment of vision-threatening diabetic eye disease significantly affect vision outcomes in patients with diabetes, and most cases of severe vision loss are avoidable. Ocular telehealth technology is now well established as an effective adjunct method to increase adherence to guidelines for assessment of diabetic retinopathy and achieve all three Triple Aim goals.

Numerous programs have demonstrated that diabetic retinopathy telemedicine programs with acquisition of retinal images at the point of care in primary care locations can effectively increase rates of eye examinations among patients with diabetes and even reduce the rate of blindness and vision loss. ^12,13 The benefits of ocular telehealth programs to remotely evaluate for diabetic retinopathy are perhaps best exemplified by the United Kingdom National Health Service (UK NHS), which reports that, for the first time in 5 decades, the leading cause of blindness in working-age adults in England and Wales is no longer diabetic retinopathy. ¹⁴ This outcome was largely achieved with the nationwide telemedicine diabetic retinopathy screening program, which is in place in England and Wales and has attained a very high uptake rate.

Both the American Academy of Ophthalmology (AAO) and the American Telemedicine Association (ATA) have stressed the need for validation of diabetic retinopathy screening programs. ^15,16 The accepted gold standard for identifying diabetic retinopathy remains the Early Treatment Diabetic Retinopathy Study (ETDRS) 30-degree, stereoscopic, seven-standard field, color, 35-mm slides and, more recently digital images, evaluated by experienced readers. ¹⁷ Diagnostic accuracy is often measured with sensitivity (true positive rate) and specificity (true negative rate) with comparison to a gold standard reference. Additional standard statistical measures to assess reliability and reproducibility include kappa values for agreement of diagnosis, false-positive and false-negative readings, and positive predictive value and negative predictive value for identifying levels of retinopathy and macular edema. ¹⁶

In the ATA Telehealth Practice Recommendations for Diabetic Retinopathy, four categories of validation are described for diabetic retinopathy telehealth programs using ETDRS seven-standard field photographs as the reference standard. ¹⁶ Category 1 validation indicates a system that can identify patients with no or minimal diabetic retinopathy from those who have more than minimal diabetic retinopathy. Category 2 validation indicates a system that can determine accurately if vision-threatening diabetic retinopathy (diabetic macular edema or severe nonproliferative or worse levels of diabetic retinopathy) is present or not. Ocular telehealth programs in the United States are most often Category 2 programs. Category 3 validation indicates a system that can identify ETDRS-defined levels of diabetic retinopathy and macular edema sufficiently accurately to allow patient management and treatment. A Category 4 validated system matches or exceeds ETDRS photographs in the ability to identify levels of diabetic retinopathy and diabetic macular edema. The category of validation required for an individual telemedicine diabetic retinopathy program depends on its specific goals and objectives.

In the UK NHS, a sensitivity of 80% and specificity of 95% has been suggested as a minimum performance threshold. ¹⁸ However, sensitivity and specificity measures will vary by the clinically relevant diagnostic target (ie, sensitivity and specificity for the presence of vision-threatening diabetic retinopathy versus presence of any diabetic retinopathy will be different). A meta-analysis of validated diabetic retinopathy telemedicine programs described in the literature revealed that the pooled sensitivity of telemedicine exceeded 80% in detecting the absence of diabetic retinopathy and low- or high-risk proliferative diabetic retinopathy. ¹⁹ It exceeded 70% in detecting mild or moderate nonproliferative diabetic retinopathy and clinically significant macular edema. The pooled sensitivity was 53% in detecting severe nonproliferative diabetic retinopathy. The pooled specificity of telemedicine was 89% or better. Diagnostic accuracy is generally higher with digital images obtained through dilated pupils and, in particular, with wide-angle imaging devices. ^2,20 Although it is not the intended purpose of telemedicine diabetic retinopathy programs to evaluate for other ocular diseases, nondiabetic retinopathy ocular findings are relatively common. ²¹ Protocols must be in place to determine which findings would require referral and evaluation even in the absence of diabetic retinopathy.

Accuracy and reliability of ocular telehealth programs for diabetic retinopathy are also affected by the unreadable image rate. Published reports of unreadable image rates in various telehealth diabetic retinopathy programs range from 3% to 35%. ²² Image quality is affected by multiple factors, including age, media opacity such as cataract and vitreous hemorrhage, and small pupil size. ^20,22 Telehealth diabetic retinopathy programs may utilize pupillary dilation, whereas others perform imaging with a nonmydriatic camera and undilated pupils. Some programs also utilize selective mydriasis based on age or image quality. Generally, a higher unreadable rate has been reported with undilated pupils, especially in older individuals who also have some degree of cataract formation. ¹⁶ In addition to patient inconvenience and time constraints, the potential risk of angle-closure glaucoma is sometimes cited as a reason for avoiding pupil dilation in the primary care setting. However, the risk of inducing angle-closure glaucoma with low-dose mydriatics is minimal with no reported cases in a large meta-analysis. ²³ Nonetheless, offices with mydriatic systems should have a defined protocol to recognize and address this potentially serious complication.

State-of-the-art retinal imaging devices generally do not require a trained ophthalmic photographer to obtain quality retinal images. However, screening in the primary care setting with imaging obtained by office personnel rather than a dedicated imager may result in imagers who acquire only a small number of images at infrequent intervals, which may also affect the overall image quality. Personnel acquiring images should have demonstrated qualifications for obtaining images of adequate diagnostic quality and need to be monitored on an ongoing basis to ensure consistent image quality.

Another essential element of telehealth diabetic retinopathy programs is the remote reading center where images are evaluated. Image readers range from nonlicensed technical readers to ophthalmologists with specialty training in retina. In the United States, technical readers have been successfully used for many years at academic reading centers to support clinical trials. They are less often used for community-based telemedicine diabetic retinopathy programs. Technical readers may add business and operational efficiencies to a reading center but also require careful supervision by eye care providers, standardized procedures for training, and effective quality measures. ²⁴ Image readers need to be qualified and, ideally, certified to grade and interpret retinal images, especially if nonlicensed nonophthalmic personnel are utilized. Protocols need to be in place to assess image reading capabilities of individual readers with intragrader and intergrader agreement, in an ongoing fashion with a sample size appropriate to the size of the screening program.

Quality assurance processes provide guidance on methods to ensure ongoing quality and performance improvement. They may be quite complex and difficult to execute for telemedicine diabetic retinopathy surveillance programs. Although no uniformly adopted quality assurance guidelines are in place in the United States, the UK NHS has developed comprehensive protocols for their national diabetic retinopathy screening program to assess performance and safety, including reading centers. ²⁵ Quality assurance metrics and performance indicators will vary based on program goals and objectives. Certain clinical outcome measures, however, are important for all programs, such as the eye examination rate among patients with diabetes, the ungradable image rate, and image reviewer performance measures. Reasonable turnaround times for image evaluation and return of the report to the ordering physician need to be set and monitored. Additionally, recommendations need to be established for referral urgency and timing for varying levels of disease severity. More difficult to measure but equally important for an effective diabetic retinopathy program is the rate of compliance with referral recommendations, rate of intervention for advanced disease, and ultimately, the rate of vision loss in the population being screened. Only if such data are systematically collected and analyzed will we realize the full potential of telemedicine for diabetic retinopathy and how it aligns with the Triple Aim health care policy.

As one of the Triple Aim health policy objectives, comprehensive quality assurance programs will also assess patient satisfaction. Multiple studies show high levels of acceptance or preference for telemedicine as an alternative to conventional dilated retinal examination for diabetic retinopathy based on multiple factors, including patient convenience, cost, and perceived quality. ²⁶

The diagnostic accuracy of using digital imaging and the high sensitivity of telemedicine systems to detect clinical levels of diabetic retinopathy indicate that they may appropriately be widely utilized for diabetic retinopathy evaluation. A systematic review of the economic evidence for diabetic retinopathy screening reveals that all studies have demonstrated it is also a cost-effective modality. ^27–29 Furthermore, cost avoidance for health systems may be appreciated if disease is detected early and prompt treatment is initiated. However, significant barriers to widescale implementation of telemedicine diabetic retinopathy screening remain in the United States. Economics are a substantial concern, with the high cost of acquiring and operating imaging equipment coupled with unreliable reimbursement for the diagnostic procedure. Although placing imaging equipment in all primary care settings would greatly benefit noncompliant patients and improve disease detection across the board, the expense of such an undertaking is not realistic in the current health care economies.

Reimbursement for telemedicine diabetic retinopathy screening remains unclear. Most commercial payors in the United States understand the benefits gained by timely evaluation for diabetic retinopathy and are covering telemedicine services for this purpose. The Centers for Medicare and Medicaid Services, however, do not have a uniform coverage policy. Most telemedicine diabetic retinopathy service providers are billing using the Current Procedural Terminology (CPT) code for fundus photography (92250) with varying reimbursement success. Retinal telescreening codes also exist, but are often not applicable or useful. CPT code 92227 describes “remote imaging for detection of retinal disease (e.g., retinopathy in a patient with diabetes) with analysis and report under physician supervision,” whereas CPT code 92228 is designated for “remote imaging for monitoring and management of active retinal disease (e.g., diabetic retinopathy) with physician review, interpretation and report.” ³⁰ The descriptor for 92227 is not accurate for most telemedicine diabetic retinopathy screening programs, as the image interpretation is generally performed by a licensed eye care provider rather than by a nonlicensed technician under physician supervision. Because no physician work is involved, reimbursement for CPT 92227 is minimal and does not cover the actual costs of most programs. On the other hand, CPT code 92228 is assigned reasonable reimbursement but is only applicable if diabetic retinopathy (or other active eye disease) is present. As expected, most screening studies report a high percentage of patients have no appreciable diabetic retinopathy and therefore CPT code 92228 often does not come into play. Fortunately, as telemedicine diabetic retinopathy systems become more widely accepted and acknowledged as a useful adjunct to in-person examination, reimbursement is becoming more consistent. Additionally, pay-for-performance health care measures are aligned with the Triple Aim policies and provide incentives and/or penalties for achieving or missing target metrics for diabetic retinopathy screening rates among the population with diabetes mellitus.

Telemedicine diabetic retinopathy programs have matured rapidly in recent years and are being increasingly used worldwide to increase the rate of annual eye evaluations for patients with diabetes. Although a properly integrated telemedicine retinal imaging system does not replace a comprehensive eye examination, the resultant improved surveillance for diabetic retinopathy results in greater timely access to effective treatments and realization of improved clinical outcomes.

Due to the high current global prevalence of diabetes, it is estimated that seven retinal examinations must occur every second to fulfill guidelines of annual retinal screening for all diabetic patients. ⁸ Even though telemedicine has the potential of increasing efficiency of access for people, it can increase the burden of image interpretation by physicians and graders. Therefore, automated computer-based grading systems were developed to meet the increasing eye care demand. These systems are capable of distinguishing normal structures from diabetic lesions, such as hemorrhages or cotton wool spots. ²⁸ Based on the type, severity, and extent, images are graded for the presence or absence of diabetic retinopathy. Furthermore, automated systems can be adjusted in order to improve the balance between sensitivity and specificity. To minimize false-negatives, a high sensitivity is a desirable characteristic of such a computerized system. The disadvantage would be a lower specificity, which requires more images to be regraded by physicians, reducing efficiency and increasing the cost of screening programs. However, such systems would serve a prescreening function and on a large scale, still decrease overall workload on the reading center staff. ^31,32

Glaucoma is a progressive form of optic neuropathy associated with visual field defects and loss of retinal ganglion cells. High intraocular pressure (IOP) is a major modifiable risk factor for the development and progression of glaucoma but alone is not sufficient for a diagnosis of glaucoma. Glaucoma is a leading cause of irreversible visual impairment, affecting 60.5 million individuals worldwide in 2010. ³³ This number is expected to increase to approximately 79.6 million by 2020. ³⁴ Because there is no cure for glaucoma, this condition can progress to blindness if left untreated. ³⁵ Moreover, older people are at a greater risk of developing glaucoma, and therefore, an aging population will require more frequent screening. The recommendation for screening exams for glaucoma is every 2 to 4 years for adults between the ages of 40 and 64 years and every 1 to 2 years at age 65 and older. ^35,36

The economic burden of the treatment of glaucoma is significant and increases with severity of disease. ³⁴ Glaucoma typically progresses without symptoms and can present at advanced stages without the patient being aware of visual field loss. Therefore, similar to diabetic retinopathy, it is important to detect, diagnose, and treat patients at the earliest stages, both to prevent vision loss and improve quality of life and to decrease health care costs. Teleophthalmology in the field of glaucoma, or teleglaucoma, is a relatively new method of screening for and monitoring glaucoma and may improve access and early detection of disease.

Unlike diabetic retinopathy, which has very well-defined levels of severity that are uniformly accepted and detected with retinal imaging, glaucoma evaluation may involve a variety of diagnostic tools, including assessment of IOP or tonometry, corneal pachymetry or central corneal thickness measurements, visual field tests or perimetry, and imaging of the optic disc. The more tools that are used during the screening process, the greater the accuracy and effectiveness of the screening. ³⁵ Stereoscopic fundus photographs, including images of the optic disc, may be evaluated for signs of glaucomatous damage, including an increased cup-to-disc ratio of the optic nerve and other characteristic features ³⁷ (Figure 7-2). Glaucoma evaluation may involve more sophisticated diagnostic tools of optic nerve imaging such as OCT and confocal scanning laser ophthalmoscopy, which are instruments that provide more detailed topographic information about the three-dimensional structure of the cup and structural information about retinal nerve fiber layer thickness (Figure 7-3). However, the rapidity of evolving new structure analysis technology limits the number of longitudinal studies investigating progression with these techniques.

Standard in-person glaucoma screening typically includes history taking, slit lamp examination, visual field testing (Figure 7-4), and fundus photography performed by an eye care provider. Teleglaucoma screening platforms consist of various models, designed based on the resources of the program. Some programs consist of ophthalmologists evaluating images, and others involve a collaboration between ophthalmologists and optometrists. ³⁸ Typically, patients undergo IOP and ultrasonic corneal thickness measurements by a specialized technician. These data, along with stereoscopic digital images of the optic disc, are then electronically transmitted to an ophthalmologist or glaucoma specialist for interpretation. Although remote grading services may be done after the patient visits, some sites offer real-time consultation. ³⁸

Goldmann applanation is considered the gold standard for IOP measurements. However, noncontact tonometers are more portable and require less skilled operators for effective use. ³⁹ In the future, home monitoring may become possible using a contact lens sensory device or other types of home tonometers, which allow more frequent monitoring of tonometry at various times of the day. ^40–42 Such data can enable patients to become more actively involved in self-monitoring and in sharing data directly with screening centers and physicians. ⁴³

Because there is no single clear, gold-standard definition for glaucoma, validation studies for teleglaucoma programs remain challenging. The modalities that are used by different teleglaucoma programs can vary considerably, particularly the availability of the more expensive imaging devices such as OCT or confocal scanning laser ophthalmoscopy. Due to the differences between modalities and screening parameters used in various teleglaucoma programs, analyses comparing their findings are challenging. However, several studies have found that teleglaucoma has comparable diagnostic accuracy to in-person examination for the detection of glaucoma.

A review by Thomas et al. reported that teleglaucoma is less sensitive (83.2%) and more specific (79%) than face-to-face clinical examination in detecting glaucoma. ³⁵ In comparison to an in-person slit lamp examination, the positive predictive value for a positive diagnosis was 77.5%, and the negative predictive value for a negative teleglaucoma diagnosis was 82.2%. ³⁵ Similar to diabetic retinopathy telemedicine programs, evaluation of photographs depends on the experience of the photographer as well as expertise of the grading physician. A study from Kenya found that 24% of teleglaucoma photographs were determined to be unreadable due to media opacities, patient cooperation, and poor photographic techniques. ⁴⁴ Furthermore, if the image quality is low and the grading physician's expertise is variable, diagnostic accuracy can decrease. The sensitivity in this study was reported at 41.3% and specificity at 89.6%. ⁴⁴

Teleophthalmology can be used in the postsurgical management of glaucoma. Studies have evaluated images of postsurgical blebs (filtering site) acquired using a still slit lamp image as well as video images. ⁴⁵ Remote assessment had high levels of agreement for the determination for vascularity, bleb leak, and anterior chamber depth. ⁴⁶ However, agreement was variable for other assessments, including bleb height and bleb wall thickness. This model may be useful for postoperative care in remote regions. Long-term postoperative monitoring can be comanaged by local physicians and the surgeon via teleglaucoma in regions where surgical expertise is scarce.

Multiple studies agree that the majority of patients who undergo glaucoma screening do not require an in-person consultation with a glaucoma specialist. Therefore, glaucoma specialist expertise can be reallocated to patients with more advanced disease who require surgical management and closer monitoring or those who have a condition with greater diagnostic challenge. In a study conducted in the Netherlands, one-fourth of 1,729 subjects required additional examination, but only 11% consulted a specialist. ⁴⁷ A teleglaucoma study in a remote region over 4 years demonstrated that most cases (three-fourths) did not require face-to-face consultation with a specialist and could be managed through remote collaboration. ⁴⁸ The majority (69%) were managed by the referring local optometrist. Only 27% of patients were referred for in-person glaucoma evaluation and 48% of patients required repeat teleconsultation. There was additional benefit in being able to initiate treatment before the patient was seen for an in-person consultation. In the teleglaucoma program, 87% of patients with definite glaucoma and 28% of glaucoma suspects received earlier treatment.

The goal of teleglaucoma is to improve access to specialized care. Studies have shown that teleglaucoma improves access time, defined as time from patient referral to the date a visit is booked. In one study, this time was reduced from 88 days to 45 days. ⁴⁹ Moreover, teleglaucoma reduced cycle time, which is the time spent from registration until departure from clinic, from 115 to 78 minutes. ^35,49 In a meta-analysis, patient travel time was reduced and patient satisfaction with teleglaucoma was higher compared to in-person examination. ³⁵

As with other teleophthalmology programs, costs in teleglaucoma are associated largely with the type of diagnostic equipment. A meta-analysis of glaucoma cost analysis studies demonstrated that teleglaucoma costs varied by the capacity of service and type of equipment available. ³⁵ The costs for sophisticated glaucoma equipment can be greater than $100,000. Cost effectiveness is difficult to compare across studies due to the variability in modalities used by different programs. Further analyses demonstrated that teleglaucoma saved $27,460 per quality adjusted life year per patient screened compared to in-person examination. ⁵⁰ Reimbursement issues for teleglaucoma are similar to those for diabetic retinopathy telemedicine programs. There are no specific CPT codes for teleglaucoma. Glaucoma diagnostic procedures are generally covered by commercial and government payors in the United States. Teleconsults, however, are not typically billable for glaucoma screening.

Glaucoma can be classified as open angle or closed angle, based on the anatomical structure of the outflow channel or iridocorneal angle of the eye. This structure is evaluated by gonioscopy at the slit lamp, which requires a contact lens with mirrors enabling assessment of the iridocorneal angle. However, gonioscopy is a skill that is difficult to acquire and has only moderate agreement reported among observers. ^51–53 The cases evaluated in the literature in teleglaucoma likely include glaucoma resulting from various mechanisms. Primary angle-closure glaucoma is more common in populations in East and Southeast Asia. Screening programs generally do not include gonioscopy and have the potential to underdiagnose angle-closure glaucoma, which can be treated very effectively and prevented with laser iridotomy.

Given the variability in teleglaucoma programs, quality assurance issues have not been addressed in any detail. However, similar to diabetic retinopathy telemedicine programs, performance metrics should include monitoring images from a technical standpoint as well as interpretation of images, reporting times, and referral/treatment times. In glaucoma management, the detection of false negatives can be a challenge, especially if cost limits use of diagnostic equipment. Therefore, in teleglaucoma, there is a risk of accepting an “unsafe” system. ³⁹ However, repeated screening over time of a chronic condition should decrease the number of patients with true disease who are left undetected through telescreening. Further studies and outcomes data will be essential as teleglaucoma programs become incorporated into mainstream ophthalmology.

Worldwide ROP is a major potentially avoidable cause of childhood blindness. ROP is a vasoproliferative disease of the developing retina that can develop in low-birth-weight premature infants. The risk of severe irreversible vision loss is decreased significantly if the disease is detected and treated appropriately in a timely manner. To that end, ongoing screening examinations of these infants are required until the retinal vasculature has matured. The standard or reference examination technique is a bedside examination with binocular indirect ophthalmoscopy, which needs to be repeated at regular intervals until the infant is no longer at risk or the ROP has regressed. For a variety of reasons, including significant medicolegal liability concerns, an increasing rate of premature births and at-risk infants, the complexities of coordinating examinations, and the remote location of some neonatal intensive care units, there is an insufficient supply of qualified ophthalmologists willing to screen at-risk infants for ROP in the United States and elsewhere. Teleophthalmology services for ROP utilize wide-field imaging technology in a manner similar to imaging performed as part of diabetic retinopathy screening programs. Images are obtained from at-risk infants with a wide-angle retinal camera in the neonatal intensive care unit and are transmitted securely through the Internet to a viewing platform or reading center for review by an expert.

A number of studies provide level 1 evidence demonstrating that interpretation of wide-angle retinal photography by remote readers compared to the reference standard of bedside dilated ophthalmoscopic examination by an expert clinician has high accuracy for telemedicine detection of moderate and severe ROP disease. ⁵⁴ As with diabetic retinopathy programs, there is significant variability among ROP telemedicine programs, including number of images taken per eye, background of personnel acquiring images, expertise of image readers, diagnostic outcome measures, and metrics of accuracy. ⁵⁴ One of the largest studies, by Quinn and colleagues, reporting on a real-world operational telemedicine ROP screening program, revealed a sensitivity of 90% and a specificity of 87% of infants with referral-warranted ROP. ⁵⁵ Although differences in methods preclude direct comparison, collectively, the level 1 studies reveal a sensitivity ranging between 57% and 100% and a specificity ranging from 37% to 98% for the detection of moderate to severe ROP by digital retinal photography. ⁵⁴

As previously mentioned, a major criterion for telemedicine programs in ophthalmology is rigorous performance validation relative to a reference or gold standard. The gold standard in diabetic retinopathy and other retinal diseases is based on retinal image evaluation and is well defined. For ROP, however, the gold standard is clinical examination with binocular indirect ophthalmoscopy. Interestingly, the availability of wide-field retinal imaging and telemedicine ROP programs raises questions about the appropriateness of the current gold standard. ⁵⁶ In the e-ROP study (telemedicine approaches to evaluating acute-phase ROP), expert review of discrepant cases between readers reviewing images and the findings described by an examining ophthalmologist found that the consensus panel more often agreed with the image readers, suggesting that for certain findings, retinal imaging is better than clinical examination. ⁵⁷ However, evaluation of the far peripheral retina, which cannot be reliably imaged even with existing wide-field technology, is still necessary in the staging of ROP. Even though the interpretation of digital retinal images, in some instances, may be more accurate than bedside examination and serves as a useful adjunct method to reduce the burden on examining ophthalmologists, it cannot be considered a replacement for binocular indirect ophthalmoscopy.

Reliably imaging the retinal periphery in infants is difficult, which sometimes results in poor image quality. Significant variability in image evaluation, even among experienced clinicians, presents another challenge. ⁵⁸ On the other hand, documentation of findings with serial imaging may allow for better determination of disease progression compared with a traditional examination and documentation with retinal drawings and notes in the clinical record.

As with other teleophthalmology modalities, an inability to obtain interpretable images constitutes a screen-positive finding triggering a referral for an onsite examination. Once a diagnosis of referral-warranted ROP is made, resources and protocols for bedside examination and possible treatment, including transfer when necessary, must be in place.

The cost of implementing a telemedicine ROP screening service is largely driven by the cost of the retinal camera, but significant infrastructure needs must also be considered. A joint technical report by the AAO, American Academy of Pediatrics, and American Association of Certified Orthoptists provides useful recommendations and practical considerations for a telemedicine approach to ROP screening. ⁵⁴ The guidelines discuss the importance of the health care team approach, including imaging protocols and standard image sets, infant monitoring, data transmission, return of interpretation report, and recommendations and termination criteria.

Quality assurance measures for telemedicine ROP programs are similar to those for diabetic retinopathy and, in addition to validation, include the ungradable image rate, image reviewer performance indicators, report return time, rate of intervention for advanced disease, and tracking of long-term visual and ocular structural outcomes.

Billing for telemedicine consults is generally not possible for ROP screening services, but reimbursement is often provided on a contractual basis between the neonatal intensive care unit and the eye care providers.

Although the implementation of telemedicine for ROP screening continues to increase, further studies on clinical and cost effectiveness, long-term outcomes, and validation of protocols are needed.

In the past decade, public health attention has focused on age-related macular degeneration (AMD) as it remains a leading cause of vision loss in the United States and the world, and its prevalence is expected to increase with the rising elderly population. ⁹ If left untreated, exudative AMD leads to irreversible central vision loss. Recent availability of intravitreal anti–vascular endothelial growth factor (VEGF) therapy and other innovative treatments makes efficient screening for early detection crucial to identify patients at risk for vision loss. Despite recommendations for regular comprehensive eye examinations in older individuals, many elderly persons do not have access to specialist care for evaluation for AMD. Although telemedicine technology may be a valuable adjunctive tool to screen for AMD, there has been little utilization of this technology to date, possibly because effective treatments have only recently become available. Similar to telemedicine diabetic retinopathy programs, digital retinal images may be acquired and transferred to a remote reading center for detection of the characteristic clinical findings of AMD. Few studies have evaluated the feasibility, accuracy, and reliability of telemedicine AMD screening, and even fewer have discussed patient satisfaction and cost effectiveness. ²⁶

The use of OCT, which has transformed the management of AMD with its ability to identify exudation, will also need to be explored as telemedicine becomes more regularly incorporated into telemedical AMD care. A home telemedicine monitoring device to detect the progression of AMD is now also available and has shown early effectiveness. ⁵⁹ However, questions about access, affordability, and cost effectiveness remain, and patients with the greatest chance at benefit need to be carefully selected. ⁶⁰ Telemedicine approaches show promise for the evaluation of AMD, but additional studies and outcomes data are needed before widespread adoption is possible.

The role of teleophthalmology continues to expand rapidly, and its impact on providing adjunct methods of eye care delivery is being felt in all specialties of ophthalmology. Although most commonly used for diabetic retinopathy assessment and ROP screening, innovative technology solutions are allowing telemedicine systems to be utilized for screening, diagnosis, and management of an ever-growing number of ophthalmic diseases, including glaucoma, AMD, ocular trauma, anterior segment pathologies, and adnexal and orbital diseases. Early disease detection and improved access to specialty care are increasingly important as new treatment modalities become available, and teleophthalmology is assuming a vital role in filling the demand and helping to improve patient outcomes. Research to understand the progress that has been demonstrated to date and barriers to further implementation are important areas for future studies in teleophthalmology.