Comprehensive diabetes screening is an important component to the treatment of diabetes. Untreated diabetes is a perfect storm to the body. A well-controlled disease can become manageable. The choice is on the patient and we are here to make that choice backed up by medical knowledge and facts.

Having in mind all the tools we have at our hands to put diabetes under control, it’s hard to explain why global health suffers from it.

When talking about diabetes complications, it all comes down to a deterioration of nerves and blood vessels throughout the body.

Preventing all those complications essentially means putting the blood sugar under control by medications, diet, lifestyle changes and attending screening programs.

Diabetic Retinopathy (DR)

Diabetic Retinopathy is a condition in which the retina—a lining at the back of the eyeball that “translates” light stimuli into nerve impulses that make eyesight possible, slowly deteriorates under the influence of badly controlled diabetes.

Currently, it affects approximately 100 million people in the world. Research shows that in only 20 years (1990-2010), visual impairment and blindness related to DR increased by 64% and 27%, respectively 1.

It all starts with slight functional impairment of the retina’s neurons. However, the first visible manifestations are microaneurisms (localized enlargement of small arteries) and intraretinal hemorrhages (bleeding). The damage brings circulation in some areas of the retina to a halt which causes more damage – cotton wool spots, new hemorrhages, and abnormalities of the retinal veins. All the changes mentioned above lead to “leakage” of the fluid from the blood vessels into the retina which causes its thickening and impaired vision. Insufficient circulation triggers the growth of new blood vessels. Although this might sound like a good thing, it isn’t because the whole process is uncontrolled and does more harm than good. The condition takes its toll on eyesight- if left untreated it causes severe vision impairment or blindness.

Diabetic Retinopathy can occur at any age. Timely detection is crucial for successful treatment.

Diabetic Retinopathy Screening

The sole purpose of screening is to identify patients with early signs of DR and lead them through further diagnostics and treatment. Generally speaking, there is no such thing as a perfect screening method in medicine- some are not sensitive enough (patients with the condition “get away” as healthy), others are not specific enough (instead of recognizing a specific condition, the test “picks up” patients with another disease) and some are too complicated or too expensive to carry out in a large population. To overcome the limitations of screen tests, it is crucial to attend them regularly (usually once a year).

Educating patients, their friends and families about the importance of regular checkups and screening programs is a first step towards the early detection of DR. Many patients are surprised to find out DR may be silent for years and that the initial symptoms are usually a sign the condition has heavily taken its toll on the retina.

The screening process is simple and painless. The program includes taking a medical history, ophthalmic examination, and analyzing high-quality photographs of the retina (made with a specialized camera) and its purpose is to determine which patient needs a referral to an ophthalmologist (detailed examination, close follow-up, treatment) and which needs just an annual screening.

The screening for DR starts five years after the onset of a disease in cases of DM type 1, while patients with type 2 DM should be included in the screening program at the time of diagnosis.

As mentioned earlier, putting diabetes under control and minimizing the risk of complications comes down to a good blood glucose control. The most important parameter of blood glucose control in patients with diabetes is HbA1c. Generally speaking, keeping it under 7.0% significantly reduces the risk for DR. Those which condition requires a close follow up (regular ophthalmologist control) should aim to keep the HbA1c below 6.5% 2.

The methods of screening

There are a few different methods that can be used to assess and classify diabetic retinopathy; ophthalmoscopy (direct and indirect), digital color or monochromatic photography (mydriatic or nonmydriatic), and stereoscopic color film fundus photography 3. Different methods have different sensitivity- while direct ophthalmoscopy has the poorest sensitivity, stereoscopic color fundus photographs in 7 standard fields have been a golden standard for early DR detection for the past few decades. Because of the technical limitations, the method is not an ideal screening method (it requires too many resources), but when it comes to reliability it’s the best medicine has to offer.

Single field fundus photography takes the best of both worlds- interpreted by a trained professional its reliability comes close to the gold standard and it’s quick. However, it’s not a substitute for a comprehensive ophthalmic exam, but an excellent tool for selecting patients who need a close follow up.

The limitation of all screening programs

No matter how good the screening method is and how effective available treatments are if the patient doesn’t show up on an examination all those benefits are for nothing. Non-attendance has been linked with a severe form of DR and vision loss. Some studies suggest that less than half of patients already diagnosed with DR completes the course of laser treatments after 6 months follow up 4!

As for the patient compliance with the screening programs, the research results vary between different authors. Out of 100 patients invited for screening, 70-90 shows up on the first screening session. The percentage tends to drop over time 5.

The reasons for non-attendance are many. While the results are pretty much the same- high risk of vision loss and blindness.

How Topcon Screen helps

Topcon Healthcare Solutions diabetic retinopathy screening program, Topcon Screen, allows primary care physicians, endocrinologists, and internal medicine doctors to provide a reliable eye screening service for their diabetic patients. By offering the comprehensive eye screening service right where the diabetic patients are, with the family doctor, the screening compliance percentages are expected to improve.

References:

  1. Global Estimates on the Number of People Blind or Visually Impaired by Diabetic Retinopathy: A Meta-analysis From 1990 to 2010. Leasher JL, Bourne RR, Flaxman SR, Jonas JB, Keeffe J, Naidoo K, Pesudovs K, Price H, White RA, Wong TY, Resnikoff S, Taylor HR, Vision Loss Expert Group of the Global Burden of Disease Study. Diabetes Care. 2016 Sep; 39(9):1643-9.
  2. https://annals.org/aim/fullarticle/2674121/hemoglobin-1c-targets-glycemic-control-pharmacologic-therapy-nonpregnant-adults-type
  3. Hutchinson A, McIntosh A, Peters J, et al. Effectiveness of screening and monitoring tests for diabetic retinopathy – a systematic review. Diabet Med 2000;17:495-506.https://ebm.bmj.com/content/ebmed/6/2/56.full.pdf
  4. (2015). Improving patient compliance with diabetic retinopathy screening and treatment. Community eye health, 28(92), 68-9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4944097/
  5. Kashim, R. M., Newton, P., & Ojo, O. (2018). Diabetic Retinopathy Screening: A Systematic Review on Patients’ Non-Attendance. International journal of environmental research and public health, 15(1), 157. doi:10.3390/ijerph15010157 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5800256/