Diabetic Retinopathy Screening and Monitoring: Smarter Tools for Better Outcomes

Table of Contents

What are the diabetic retinopathy screening methods?

Fundus images in DR screening

Can OCT detect diabetic retinopathy?

What does diabetic retinopathy look like on OCT?

What are the screening intervals for diabetic retinopathy?

What are OCT biomarkers for diabetic macular edema?

Monitoring diabetic retinopathy: OCT red flags

Diabetic retinopathy treatment

Conclusion

Diabetic retinopathy (DR) remains the leading cause of irreversible vision loss among working-age adults worldwide. According to the International Diabetes Federation (IDF), one in three patients with diabetes shows signs of DR, and 10% develop diabetic macular edema (DME). Early diagnosis, systematic screening, and individualized monitoring are essential to prevent vision loss.

What are the diabetic retinopathy screening methods?

Modern methods of DR screening include:

• Telemedicine platforms with automated fundus image transmission
• FDA-approved AI-based systems
• Mobile fundus cameras with Wi-Fi synchronization for field examinations
• Smartphone-based platforms with specialized lenses

In practice, these methods are often combined. For example, patients may undergo fundus photography, after which the images are transmitted to telemedicine centers and analysed by AI algorithms. More complex cases are then referred to ophthalmologists.

DR screening is also frequently incorporated into annual diabetes checkups conducted by primary care physicians trained in basic fundus photography. This approach, already successfully implemented in several EU countries, has reduced the incidence of severe DR.

 

Innovations in DR screening have broadened access for rural residents, older adults, and individuals with limited mobility. Integration into national e-health systems enables automated reminders and electronic medical record linkage, incorporating laboratory data (HbA1c, blood pressure) alongside retinal images.

Fundus images in DR screening

Fundus photography is the optimal primary screening method due to its high diagnostic yield, cost-efficiency, simplicity, and ability to integrate with AI and telemedicine solutions. 

It enables detection of microaneurysms, hemorrhages, exudates, and neovascularization, often before symptoms arise. National screening programs rely heavily on digital fundus imaging, which, when combined with AI, provides an efficient platform for mass DR detection.

Advances in fundus imaging for diabetic retinopathy have improved efficiency. Modern non-mydriatic cameras deliver high-quality images without pupil dilation, while automated image analysis supports rapid identification of suspicious cases. Cloud storage and telemedicine platforms facilitate remote evaluation, increasing coverage in regions with limited ophthalmology services.

Next-generation wide-field cameras further enhance detection by capturing peripheral pathology. Some devices also generate automated annotations, reporting lesion type, DR stage, and DME presence, thereby standardizing interpretation and expediting clinical decision-making.

Can OCT detect diabetic retinopathy?

Although OCT has not traditionally been considered a primary screening tool for diabetic retinopathy, its role in diagnostics is steadily growing. OCT is increasingly used as a supplementary method to fundus photography, especially for detecting early signs of diabetic macular edema and morphological changes in the central retina that are not yet visible during ophthalmoscopy.

Due to its high resolution, OCT allows visualization of structural changes such as photoreceptor layer disruption, subclinical intraretinal fluid, thickening of the neurosensory retina, and foveal edema. These changes often precede clinically significant macular edema and can only be detected by OCT.

OCT is also useful for identifying other causes of vision loss in diabetic patients, for example, ruling out age-related macular degeneration.

Recent studies confirm that adding OCT to standard screening significantly increases diagnostic accuracy for DME. Therefore, many experts recommend combining fundus photography with OCT in patients with long-standing diabetes, poor glycemic control, or complaints of vision deterioration.

What does diabetic retinopathy look like on OCT?

Diabetic retinopathy OCT scans offer a unique opportunity to identify changes not always seen on fundus photography.

Typical DR OCT findings include:

• Destruction of outer retinal layers, particularly the ellipsoid zone, indicating photoreceptor damage
• Intraretinal hyperreflective foci, hard exudates
• Microaneurysms
• Changes in retinal thickness and neuroepithelial layer atrophy
• Diabetic macular edema with intraretinal hyporeflective cystoid spaces and neuroepithelial swelling
• Subretinal fluid, resulting from increased vascular permeability
• Disorganization of inner retinal layers (DRIL), an unfavorable prognostic sign associated with reduced visual acuity
• Development of epiretinal membranes

OCT also detects proliferative changes and tractional zones, which may lead to tractional retinal detachment.

Beyond structural analysis, OCT angiography (OCTA) is increasingly used to visualize microvascular retinal changes without contrast injection. OCTA helps identify neovascularization, capillary network disruption, and the extent of macular ischemia.

What are the screening intervals for diabetic retinopathy?

The screening frequency for diabetic retinopathy must be tailored to diabetes type, disease stage, and risk factors:

Type 1 diabetes

• First screening: 3–5 years after diagnosis (due to onset in children and young adults)
• Then annually, if no DR is detected
• If DR is present, frequency depends on severity

Type 2 diabetes

• Screening at diagnosis, as DR may already be present.
• If no DR, repeat every 1–2 years.

Patients with confirmed DR

• No visible DR, mild non-proliferative diabetic retinopathy (NPDR), no DME — every 1–2 years
• Moderate NPDR — every 6–12 months.
• Severe NPDR — every 3 months.
• Proliferative DR (PDR) — monthly, with regular OCT monitoring of the macula.
• DME — monthly if center-involving, every 3 months if not.

Pregnant women with type 1 or type 2 diabetes

• Screening before conception or in the first trimester, with follow-up each trimester and postpartum
• Screening is not required for gestational diabetes without pre-existing diabetes

Post-treatment patients (laser or vitrectomy)

• Typically, every 3–6 months during the first year, individualized based on retinal stability

 

What are OCT biomarkers for diabetic macular edema?

OCT is a key method for detecting DME, thanks to its ability to visualize retinal layers with micron resolution. OCT not only confirms DME presence but also identifies biomarkers with prognostic value for treatment selection, therapy response prediction, and monitoring.

Main OCT biomarkers in DME:

• Cystoid hyporeflective intraretinal spaces, usually found in the inner nuclear layer (INL) or outer plexiform layer (OPL). Their number, size, and location correlate with edema severity. Large or confluent spaces may indicate chronicity and a worse prognosis.
• Subretinal fluid (fluid between the neurosensory retina and retinal pigment epithelium). While often associated with a better visual prognosis, it requires careful monitoring and consideration in anti-VEGF therapy.
• Central macular thickening. Changes in macular thickness are key indicators of treatment effectiveness.

Monitoring diabetic retinopathy: OCT red flags

Patients with DR require ongoing monitoring to identify early signs of progression. Worrisome OCT signs of disease progression include. Worrisome OCT signs of disease progression include:

• Progressive central macular thickening despite treatment.
• Increase in intraretinal or subretinal fluid, appearance or enlargement of cystoid spaces
• Appearance of new hyperreflective foci, signaling inflammatory activity. Hyperreflective foci may precede hard exudates or RPE changes.
• Appearance or progression of DRIL. DRIL is an independent predictor of poor prognosis, even when morphological improvement is seen on OCT.
• Ellipsoid zone disruption, indicating photoreceptor damage.
• Signs of macular ischemia. Although better evaluated with OCTA, indirect signs on OCT may include thinning of the inner retinal layers.
• Tractional changes: epiretinal membrane formation, inner retinal stretching, or macular traction.

 

The appearance of these OCT signs should prompt reassessment of therapy, potential regimen adjustment (e.g., switching anti-VEGF agents, introducing steroids, or combination therapy), and referral to retinal surgeons when tractional changes are present.

Diabetic retinopathy treatment

Treatment of DR requires a comprehensive approach, taking into account disease stage, individual patient characteristics, OCT findings, comorbidities, and prognostic biomarkers.. Modern strategies include preventive, pharmacological, and surgical methods, as well as personalized medicine tools based on retinal imaging.

1. Risk stratification and treatment choice
   Therapy is chosen based on:

• DR stage (non-proliferative, proliferative, with or without DME).
• DME form (focal, diffuse, with or without subretinal fluid).
• Presence of DRIL, EZ disruption, ischemic changes on OCTA.
• Response to prior therapy (anti-VEGF, steroids, laser).
• Comorbidities (renal insufficiency, hypertension, poor compliance).

Low-risk patients may undergo observation or focal laser. Those with significant DME — anti-VEGF or steroid injections. Proliferative DR patients often require panretinal laser photocoagulation or vitrectomy.

2. Pharmacotherapy: anti-VEGF and steroids
   Anti-VEGF agents (aflibercept, ranibizumab, bevacizumab) remain first-line therapy for DME, especially effective in patients with significant edema and no ischemia. New agents with extended effects, including port delivery systems, are emerging.
   Steroids are used in persistent DME, anti-VEGF resistance, or inflammatory phenotypes.
3. Laser therapy
   Although injections have largely replaced laser for DME, panretinal photocoagulation remains standard for proliferative DR. Subthreshold micropulse laser is increasingly used for focal edema with minimal tissue impact.
4. Surgery
   Vitrectomy is indicated in cases of tractional macular edema, vitreous hemorrhage, or retinal detachment.
5. Personalization based on OCT
   Modern treatment protocols integrate OCT biomarkers for tailored strategies and prognosis. AI systems can automatically generate treatment protocols from OCT data, highly valuable where retina specialists are limited.
6. Patient education and multidisciplinary care
   Treatment success depends heavily on patient adherence. Patients must understand the need for regular injections, monitoring, and systemic control. Collaboration between ophthalmologists, endocrinologists, and family doctors ensures stable glycemic control and slows DR progression.

Conclusion

Screening and monitoring of diabetic retinopathy are evolving rapidly with advances in telemedicine, AI, and OCT-based imaging. Early detection through decentralized, technology-driven approaches, combined with individualized monitoring and biomarker-guided treatment, is critical to preserving vision. Personalized care strategies—supported by imaging technologies and multidisciplinary collaboration—offer the most effective means to reduce the global burden of DR-related blindness.