Asymmetric Diabetic Retinopathy Between Eyes
Yes, a diabetic patient can absolutely have moderate NPDR in one eye with no evidence of retinopathy in the contralateral eye—this asymmetric presentation occurs in approximately 10% of patients with diabetic retinopathy. 1
Clinical Reality of Asymmetric Disease
Unilateral or asymmetric diabetic retinopathy is a well-documented clinical phenomenon, with studies showing that 10.1% of patients with proliferative diabetic retinopathy (PDR) in one eye had only nonproliferative diabetic retinopathy (NPDR) in the fellow eye. 1
This asymmetry can be even more pronounced, with some patients having advanced disease in one eye while the fellow eye shows minimal or no retinopathy at all. 1
The pattern is most commonly observed in patients aged 50-70 years with adult-onset diabetes mellitus. 1
Pathophysiologic Considerations
Diabetic retinopathy progresses through distinct stages (no apparent retinopathy → mild NPDR → moderate NPDR → severe NPDR → PDR), but this progression does not occur synchronously between eyes. 2, 3
Each eye should be classified and managed independently using the International Clinical Diabetic Retinopathy Disease Severity Scale, as recommended by the American Academy of Ophthalmology. 2
Moderate NPDR is defined by hemorrhages and/or microaneurysms greater than standard photograph 2A, and/or soft exudates, venous beading, or intraretinal microvascular abnormalities (IRMA) present but less than severe nonproliferative retinopathy. 4
Management Implications for Asymmetric Disease
The eye with moderate NPDR requires annual follow-up examinations as recommended by the American Academy of Ophthalmology, while the eye without retinopathy requires screening every 1-2 years per American Diabetes Association guidelines. 2
Do not assume bilateral symmetry when screening or monitoring—each eye must be examined and graded separately, as the fellow eye without current retinopathy remains at risk for future development. 2
Diabetic macular edema (DME) should be assessed independently in each eye, as it can occur at any stage of retinopathy and represents a separate vision-threatening manifestation. 2, 3
Critical Clinical Pitfalls
Never delay examination of the "better" eye assuming it will mirror the more affected eye—asymmetric progression is common and each eye requires independent monitoring. 1
Systematic screening based on diabetes duration rather than symptoms is essential, as advanced stages can be present even without visual symptoms, and asymmetry between eyes can mask the severity of disease. 2
Unilateral elevated intraocular pressure was found in 20% of eyes with NPDR versus 12% with PDR, suggesting that pressure monitoring should be part of the assessment in asymmetric disease. 1