Retina and Ocular Diabetes
Diabetic retinopathy stages: what they mean for your follow-up
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In brief: Diabetic retinopathy has four stages: mild, moderate, and severe nonproliferative diabetic retinopathy, followed by proliferative diabetic retinopathy. Knowing which stage you are in helps your doctor decide how often you need checkups and which management options are most appropriate. The stage does not always match the symptoms you notice: you can have significant retinal damage without realizing it.
If you have diabetes and have just been told you have “stage two retinopathy” or something similar, it is natural to wonder: What exactly does that mean for my eyes? The stages of diabetic retinopathy precisely describe the degree of damage to the retina, and understanding them can turn uncertainty into a clear follow-up plan.
Diabetic retinopathy is a complication of diabetes that affects the blood vessels in the retina, the layer of the eye responsible for converting light into visual signals. The damage occurs because excess blood glucose gradually weakens the walls of these vessels over time. The capillaries weaken, become inflamed, and begin to lose their function.
Diabetic retinopathy is a microvascular complication that occurs in patients with type 1 and type 2 diabetes mellitus; its prevalence is strongly correlated with the duration of diabetes and glycemic control. (Diabetic Retinopathy)
Diabetic retinopathy affects 1 out of every 3 people with type 2 diabetes mellitus. In Mexico, its prevalence is 31.5%, according to ENSANUT MC 2016. (Diabetic Retinopathy) This figure explains why regular eye exams are an essential part of diabetes management, not an optional extra.
The disease is divided into two broad categories: nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR). Within the nonproliferative stage, there are three levels of severity: mild, moderate, and severe. The proliferative stage is the most advanced. This classification is used by the ETDRS system, adopted by the American Academy of Ophthalmology (AAO).
The ETDRS (Early Treatment Diabetic Retinopathy Study) classification system groups the disease into five levels: no retinopathy, mild NPDR, moderate NPDR, severe NPDR, and PDR. (AdvBlur: Adversarial Blur for Robust Diabetic Retinopathy Classification and Cross-Domain Generalization) This scale directly guides follow-up and treatment decisions.
Stage: Mild NPDR
Main retinal findings: Small microaneurysms in the retinal capillaries
Suggested exam frequency (AAO): Every 12 months
Stage: Moderate NPDR
Main retinal findings: More microaneurysms, small hemorrhages, possible exudates
Suggested exam frequency (AAO): Every 6-12 months
Stage: Severe NPDR
Main retinal findings: Extensive vessel blockage, with signals prompting the body to form new blood vessels (rule 4-2-1)
Suggested exam frequency (AAO): Every 3-4 months
Stage: PDR (proliferative)
Main retinal findings: Growth of fragile new blood vessels, with a risk of vitreous hemorrhage and retinal detachment
Suggested exam frequency (AAO): Close follow-up; as directed by your doctor
Exam frequencies are guidelines. Your specialist will adjust the schedule based on your individual case.
In the early stages, diabetic retinopathy is usually completely silent: it does not hurt or cause noticeable changes in vision. This distinguishes it from conditions such as cataracts, where blurry vision develops gradually but can be noticeable in the earlier stages. The absence of symptoms does not mean there is no damage.
Most patients who develop diabetic retinopathy have no symptoms at the beginning of the disease; changes in vision become apparent in advanced stages. (Diabetic Retinopathy)
In the moderate or severe nonproliferative stage, subtle signs may appear: slightly blurry vision, difficulty reading small print or perceiving contrast. In the proliferative stage, if vitreous hemorrhage occurs, you may see sudden dark spots or floaters, or experience sudden vision loss. These symptoms differ from "eye strain" from screen use or the progressive blurry vision typical of presbyopia.
Everyone diagnosed with diabetes should have an eye exam, whether or not they have symptoms. Patients with type 1 diabetes should have their first evaluation 5 years after diagnosis; patients with type 2 diabetes should be evaluated at the time of diagnosis, with annual follow-up afterward. (Diabetic Retinopathy Preferred Practice Pattern® - Ophthalmology)
Certain signs warrant an assessment without delay, rather than waiting for a routine appointment:
These symptoms may indicate vitreous hemorrhage or retinal detachment, conditions that require prompt evaluation by a specialist.
Diagnosis and staging are based primarily on a dilated fundus examination and retinal imaging studies. These studies allow the specialist to “see” the retina in detail and document changes accurately.
Test: Dilated fundus exam
What it evaluates: Blood vessels, hemorrhages, exudates, and new blood vessels
Clinical use: Stage classification; this is the reference standard
Test: Optical coherence tomography (OCT)
What it evaluates: Retinal layers and the presence of macular edema
Clinical use: Detects macular edema before it affects vision
Test: Fluorescein angiography
What it evaluates: Retinal circulation and areas of ischemia or leakage
Clinical use: Guides treatment decisions in advanced stages
Test: Fundus photography
What it evaluates: Documentation for comparison over time
Clinical use: Monitoring progression between visits
A comprehensive dilated fundus exam can confirm diabetic retinopathy and determine its stage. (The 4 Stages of Diabetic Retinopathy: Diagnosis and Outlook) This painless exam takes approximately 20-30 minutes, including the time it takes for the pupil to dilate.
Management varies by stage: in the early stages, metabolic control is the most effective intervention; in advanced stages, specific ophthalmic procedures are added. No treatment for the eyes replaces diabetes control.
The American Academy of Ophthalmology describes in its Preferred Practice Pattern (AAO Preferred Practice Pattern, 2024) that "the risk of diabetic retinopathy progression is directly associated with the severity level in the ETDRS classification", reinforcing the importance of knowing the exact stage.
The progression of diabetic retinopathy can be significantly reduced by maintaining stable control of blood glucose, blood pressure, and lipids. These three factors have the greatest influence on the rate of progression of retinal damage.
Early detection and treatment can reduce the risk of blindness from diabetic retinopathy by 95%. Early detection increases the likelihood of success; however, patients are often asymptomatic at this stage. Therefore, regular eye exams are essential for reducing blindness secondary to this condition. (Cost of Diabetic Retinopathy in Mexico - The International Agency for the Prevention of Blindness)
Specific habits that help protect eye health:
After 20 years of disease, 90% of cases of type 1 diabetes and 60% of type 2 diabetes will have some form of retinopathy. (Diabetic Retinopathy in Mexico - The International Agency for the Prevention of Blindness) This information should not cause alarm, but should encourage ongoing monitoring from the first day of a diabetes diagnosis.
If you have diabetes and have not had a dilated eye exam in the past year, or if your doctor mentioned a stage of retinopathy at your last visit, schedule an assessment with a retina specialist to review your case in detail and establish a personalized follow-up plan.
There is no cure that reverses damage that has already occurred, but timely treatment can stop or significantly slow its progression and protect functional vision. Strict metabolic control is the most effective measure available.
Yes. In nonproliferative stages, even the severe stage, visual acuity is often normal or nearly normal. Structural damage to the retina can be significant before a patient notices any change in vision. That is why regular exams are essential.
The frequency depends on the stage. If you have no retinopathy, exams are annual. With mild to moderate nonproliferative retinopathy, exams may be every 6 to 12 months. With severe or proliferative retinopathy, follow-up is more frequent. Your specialist will determine the appropriate interval.
Diabetic macular edema is not a stage in itself, but a complication that can occur at any stage. It involves fluid buildup in the macula and is one of the most common causes of vision loss in people with diabetes. It requires its own evaluation and treatment.
In the nonproliferative stage, existing blood vessels are damaged, but new vessels do not grow. In the proliferative stage, the retina develops abnormal, fragile new blood vessels that can bleed or cause retinal detachment, increasing the risk of severe vision loss.
Not necessarily. The eyes may differ in stage and in whether macular edema is present. That is why the specialist evaluates and monitors each eye independently at every visit.
American Academy of Ophthalmology. (2024). Diabetic Retinopathy Preferred Practice Pattern®. Ophthalmology. Available at: https://www.aaojournal.org/article/S0161-6420(24)00784-X/fulltext (Accessed 16 October 2026).
Early Treatment Diabetic Retinopathy Study Research Group. (1991). Grading diabetic retinopathy from stereoscopic color fundus photographs—an extension of the modified Airlie House classification. ETDRS Report Number 10. Ophthalmology, 98(5 Suppl), 786–806.
Mexican Social Security Institute (IMSS). (2023, May). Diabetic retinopathy: Comprehensive Care Program. Available at: https://www.imss.gob.mx/sites/all/statics/profesionalesSalud/investigacionSalud/historico/programas/16-pai-retinopatia-diabetica.pdf (accessed on 16 of October 2026).
International Agency for the Prevention of Blindness (IAPB). Diabetic retinopathy in Mexico. Available at: https://www.iapb.org/news/retinopatia-diabetica-en-mexico/ (accessed on 16 of October 2026).
International Agency for the Prevention of Blindness (IAPB). Cost of diabetic retinopathy in Mexico. Available at: https://www.iapb.org/news/costo-de-la-retinopatia-diabetica-en-mexico/ (accessed on 16 of October 2026).
Midway National Health and Nutrition Survey (ENSANUT MC). (2016). Prevalence of diabetic retinopathy in Mexico: 31.5%. Cited in: IMSS, Comprehensive Care Program — Diabetic Retinopathy, 2023.