The Importance of Diabetes Screening and Early Detection

Primary eye care providers play a significant role.

By Walter O. Whitley, OD, MBA, FAAO

Optometrists are uniquely positioned to provide a vital role in the early detection and diagnosis of diabetes. Early diagnosis and treatment can lead to better visual and overall health outcomes.

—Section Editors Derek N. Cunningham, OD, and Alan Franklin, MD, PhD

Diabetes is a major public health concern in the developed world, and its prevalence is steadily increasing. In the United States, as of 2012, more than 29 million people had diabetes, up from 26 million just 2 years earlier. Of those 29 million, more than 8 million with diabetes were undiagnosed, according to the American Diabetes Association.1

The direct medical cost of care for diabetes amounts to close to $50 billion annually, according to a study from Prevent Blindness.2 The health consequences of diabetes are also immense. Eye care providers well know that almost 30% of adults with diabetes develop diabetic retinopathy (DR), which causes about 12% of all new cases of blindness each year. People with diabetes are also 40% more likely to develop glaucoma than people without diabetes. And they are more likely to develop cataracts at a younger age and with faster progression. But DR is associated with problems outside the eye as well. Hearing loss is higher among those with DR. Periodontal disease and albuminuria are associated with DR. Worsening DR is associated with elevated diastolic blood pressure. And vision loss due to DR is associated with major depression.

For all these reasons, early detection and diagnosis of diabetes is an important goal of all health care providers, including eye care professionals. Early diagnosis and treatment can lead to better visual and overall health outcomes.

Optometrists are patients’ primary eye care provider in most cases. We see patients for 66% of all eye care visits and 78% of first-time eye care visits. The optometrist is often the first eye care professional with the opportunity to detect acute or chronic conditions of which patients may not be aware. Patients who perceive themselves as healthy, but who wear glasses or contact lenses, may see their eye doctors more often than their primary care physicians. As such, optometrists can be at the front line in detection of chronic conditions such as diabetes, complications of which may be visible in the eye before symptoms are noted.

Optometrists therefore must be aware of their role in screening for signs of diabetes, so that they can provide integrated care and communicate effectively with patients’ primary care physicians and others.


Screening for diabetes is easily integrated as part of the routine comprehensive eye examination. We check the patient’s vision and intraocular pressures, we look at the anterior chamber and the lens, and finally we look at the back of the eye through a dilated pupil. Here is where we have the opportunity to detect signs of glaucoma, macular degeneration, and diabetes.

If we see retinal hemorrhages, this should prompt questions. Does the patient have frequent urination (polyuria)? Is he or she often thirsty (polydipsia)? Any recent weight loss? Fatigue? Increased appetite? Blurred vision? Sores that do not heal? A yes answer to any of these questions can raise suspicion of the presence of diabetes.

If we see signs of diabetic retinopathy, and the patient’s symptoms raise suspicion but the patient is not aware of a diagnosis of diabetes, this is a cue for us to refer the patient to his or her primary care provider for further evaluation.

Focus on Screening and Prevention


A rapidly expanding area or research in diabetic eye care involves in vivo corneal confocal microscopy (IVCCM). These microscopes are commercially available and have historically primarily been used by corneal specialists to aid in the diagnosis of corneal infections, corneal dystrophies or infection and even pre- and postcorneal surgery evaluation. The microscopes are noninvasive and provide cellular imaging to the level of histological evaluation. Detailed analysis of the sub-basal corneal nerve plexus has shown to have direct implications to diabetes.

IVCCM has been studied in patients with both type 1 and type 2 diabetes, showing positive predictive value in both. In type 1 diabetes it has been shown to detect neuropathy even in the absence of retinopathy or microalbuminuria.1 It has also been shown to predict the future onset of peripheral diabetic neuropathy in type 1 patients.2 This has important implications for involving optometrists in the early screening and monitoring of patients with type 1 diabetes from the time of diagnosis forward.

In type 2 diabetes patients, the density of epithelial cells and nerve fibers have been shown to correlate with the duration of diabetes.3 There have also been studies that have shown that IVCCM changes are correlated with severity of disease and blood coagulation state.4

As research evolves in this area and confocal microscopes become more readily available, there is a clear opportunity for optometrists to become more intimately involved in the systemic care of their diabetic patients. IVCCM will facilitate earlier interactions between eye care providers and other members of the diabetic care team like primary care doctors and internists. IVCCM may one day be a requirement for all newly diagnosed diabetics and then used as an important maintenance tool for the early prediction of diabetic polyneuropathy.

Having eye care take the lead in the early diagnosis of these at risk diabetic patients will lead to early intervention and better patient care. Eye doctors are uniquely suited to provide this early detection modality and should play a larger role in the diabetic health care team approach.

1. Petropoulos IN, Green P, Chan AW, et al. PLoS One. Corneal confocal microscopy detects neuropathy in patients with type 1 diabetes without retinopathy or microalbuminuria. 2015;10(4):e0123517. doi: 10.1371/journal.pone.0123517.

2. Pritchard N, Edwards K, Russell AW, et al. Corneal confocal microscopy predicts 4-year incident peripheral neuropathy in type 1 diabetes. Diabetes Care. 2015;38(4):671-675.

3. Gao Y, Zhang Y, Ru YS, et al. Ocular surface changes in type II diabetic patients with proliferative diabetic retinopathy. Int J Ophthalmol. 2015;8(2):358-364.

4. Ishibashi F1, Kawasaki A1, Yamanaka E1, et al. Morphometric features of corneal epithelial basal cells, and their relationship with corneal nerve pathology and clinical factors in patients with type 2 diabetes. J Diabetes Investig. 2013;4(5):492-501. doi: 10.1111/jdi.12083.

Derek N. Cunningham, OD
• Director of optometry and research at Dell Laser Consultants in Austin, Texas

Beyond the evaluation of symptoms in the undiagnosed diabetic patient, other steps for the primary eye care provider may vary depending on the practice setting and resources available. If the provider is part of a multispecialty group, he or she may want to order blood work that can be sent to the primary care provider.

Another diagnostic tool is the ClearPath lens fluorescence biomicroscope (Freedom Meditech), which detects autofluorescence in the crystalline lens. Elevated levels of lens autofluorescence have been associated with high levels of advanced glycation end products, or AGEs, which are linked to the presence of diabetes and high glucose levels.3

This is a handy test because it is noninvasive. It has not enjoyed widespread adoption yet, but its use is becoming more common. With the rise of accountable care organizations and their focus on prevention to promote affordable care, this type of test and others that facilitate early detection may prove to be valuable.

Optos ultrawide-field fundus imaging (Optos) is another useful screening tool that is increasingly present in optometric and primary care physicians’ offices. With this modality, an optomap 200° widefield image of the patient’s retina is obtained and sent for remote screening. If any diabetic retinopathy or other type of retinal pathology is identified that would warrant further evaluation with a dilated examination, the appropriate referral can be made.

Although the Optos is a helpful tool, it does not replace a dilated eye exam because it does not provide a three-dimensional view of the retina. If patients undergo Optos imaging and screening in their primary care provider’s practice, they may think they have had an eye exam. In reality, however, this is only a remote screening for back-of-the-eye pathology. Patients should be made aware that they still need to visit their eye care practitioner regularly for comprehensive eye exams. This is where clinical integration is important—networking and communication among different medical groups to ensure that patients do not slip through the cracks.


In addition to detecting diabetes in undiagnosed patients, primary eye care providers also play a role in the ongoing evaluation of patients with established diagnoses. Primary care physicians often refer diabetic patients for a comprehensive eye exam after a diagnosis is established, and yearly eye exams are recommended in the care continuum for diabetic patients. A vital part of coordinated care of diabetic patients, whether new or established, is good communication among providers.

Whatever the direction of the referral, the importance of good communication remains paramount. Whether we are identifying diabetes for the first time or detecting the progression of diabetic retinopathy in an established patient, the primary eye care provider must communicate his or her findings to the patient’s primary care provider. If we notice progression of diabetes, this may warrant referral to a retina specialist in addition to communicating with the primary care doctor, who may have to be more aggressive in the treatment and control of the patient’s blood sugar. In this type of coordinated care, communication among all parties is essential.

Clinical guidelines for coordinated care are available from the America Optometric Association, and the American Academy of Ophthalmology publishes a preferred practice pattern for diabetic retinopathy.4,5 These guidelines dictate the frequency of exams and whether referral to specialists is warranted depending on the severity of the condition. Familiarity with these clinical guidelines is essential.

One helpful communication resource is OcuHub (, a recently developed health care information technology solution that connects eye care professionals and integrates their communications within and between health care systems. With OcuHub, eye care practitioners can share and exchange clinical information electronically with other providers. This cloud-based web-portal system allows direct messaging from primary eye care providers to specialists, and vice versa, as well as allowing scheduling coordination between practices. All of this helps practitioners coordinate their care, track outcomes, and provide primary care providers and medical groups the information they need to effectively manage each patient’s condition. OcuHub is a HIPAA-compliant resource that provides opportunities to improve gaps in care, boost Healthcare Effectiveness Data and Information Set, or HEDIS, ratings, and decrease the costs of patient care.


As primary eye care providers, when we see patients with diabetes for their annual eye examination, part of our role is emphasizing controlling all the risk factors: keeping blood sugar down, maintaining healthy weight, stopping smoking, etc.

Many large multispecialty medical groups employ diabetes educators, and even some large eye care practices have nurses or physician assistants who are diabetes educators. This is another resource we can offer to patients to help them with controlling and managing their diabetes.

However many providers are involved, and whatever the resources available, the greatest asset in the care of patients with diabetes is communication. Open lines of communication among primary care providers, primary eye care providers, and specialists, will help to ensure that patients with diabetes are getting the quality care that they need. n

1. Statistics About Diabetes; Data from the National Diabetes Statistics Report, 2014. Accessed September 4, 2015.

2. Cost of Vision Problems. The economic burden of vision loss and eye disorders in the United States. June 11, 2013. Accessed October 26, 2015.

3. Scientific rational for screening patients using autofluorescence to identify patients who may have diabetes. Freedom Meditech. Accessed September 7, 2015.

4. Eye Care of the Patient with Diabetes Mellitus. American Optometric Association. Accessed September 7, 2015.

5. Preferred Practice Pattern: Diabetic Retinopathy. American Academy of Ophthalmology. Accessed September 7, 2015.

Section Editor Derek N. Cunningham, OD
• Director of optometry and research at Dell Laser Consultants in Austin, Texas
• Founding member and chair of the American Society of Cataract and Refractive Surgery’s Integrated Ophthalmic Managed Eyecare Delivery Task Force
• Chief medical editor of Advanced Ocular Care

Medical Editor Alan Franklin, MD, PhD
• Practices at the Retina Specialty Institute in Mobile, Alabama

Walter O. Whitley, OD, MBA, FAAO
• Director of optometric services, Virginia Eye Consultants, Norfolk, Virginia; (757) 961-2944;
• Financial interest: none acknowledged