Ophthalmology Supp · Supplementary · from Ophthalmology Supp
Case 2: Diabetic Retinopathy Screening
Patient Presentation
Demographics: 54-year-old male long-haul truck driver
Chief Complaint: "My doctor sent me for an eye check. I think my vision has gotten a little blurry recently, but I figured it was just my age."
History of Present Illness: The patient is referred by his primary care physician for diabetic retinopathy screening. He was diagnosed with type 2 diabetes mellitus eight years ago but admits to poor adherence with his medications and follow-up appointments due to his work schedule. He has not had a dilated fundus examination in over four years. He reports mild blurring of his vision bilaterally over the past several months, particularly when reading road signs at a distance, but attributes this to aging.
He denies flashes of light, floaters, sudden vision loss, or eye pain. He has noticed increased difficulty driving at night. His most recent HbA1c, obtained two weeks ago, was 9.8%. He reports frequent polyuria and polydipsia. He checks his blood glucose at home "once or twice a week" with fasting readings typically in the 180-250 mg/dL range.
He has a 15-pack-year smoking history but quit smoking 3 years ago. He was told he has "borderline high" blood pressure and cholesterol at his last physical examination.
Past Medical History:
- Type 2 diabetes mellitus (8 years), poorly controlled
- Hypertension, suboptimally treated
- Hyperlipidemia
- Obesity (BMI 34.2)
- Peripheral neuropathy in both feet (diagnosed 2 years ago)
- Microalbuminuria noted on last urinalysis
Medications:
- Metformin 1000 mg twice daily (admits to missing doses frequently)
- Glipizide 10 mg twice daily
- Lisinopril 20 mg daily
- Atorvastatin 40 mg daily
- Aspirin 81 mg daily
Social History:
- Former smoker (quit 3 years ago, 15-pack-year history)
- Drinks 2-3 beers on weekends
- Long-haul truck driver, sedentary lifestyle
- Diet high in processed and fast food
- Divorced, lives alone
Family History:
- Father: type 2 diabetes, died of myocardial infarction at age 63
- Mother: type 2 diabetes, hypertension, alive at age 78
- Brother: type 2 diabetes diagnosed at age 45
Physical Examination
- Vital Signs: BP 148/92 mmHg, HR 78 bpm, RR 16/min, Temp 36.7°C, BMI 34.2 kg/m²
- Right Eye:
- Visual acuity: 20/50 (pinhole improvement to 20/40)
- Anterior segment: unremarkable, no neovascularization of the iris (NVI)
- IOP: 17 mmHg
- Dilated fundus examination:
- Multiple dot-and-blot hemorrhages in all four quadrants
- Hard exudates forming a circinate ring temporal to the macula
- Cotton-wool spots (4 total across both hemifields)
- Venous beading in two quadrants
- Intraretinal microvascular abnormalities (IRMA) noted superior-temporal
- No neovascularization of the disc (NVD) or elsewhere (NVE)
- Clinically significant macular edema suspected (retinal thickening within 500 μm of foveal center)
- Left Eye:
- Visual acuity: 20/40 (pinhole improvement to 20/30)
- IOP: 16 mmHg
- Dilated fundus examination:
- Scattered dot-and-blot hemorrhages in two quadrants
- Microaneurysms, predominantly temporal to macula
- Rare hard exudates
- One cotton-wool spot
- No IRMA, venous beading, or neovascularization
- No macular edema
Workup and Results
Laboratory Studies:
| Test | Result | Reference Range |
|---|---|---|
| HbA1c | 9.8% | <7.0% (diabetic goal) |
| Fasting glucose | 228 mg/dL | 70-100 mg/dL |
| Creatinine | 1.3 mg/dL | 0.7-1.3 mg/dL |
| eGFR | 62 mL/min/1.73m² | >90 mL/min/1.73m² |
| Urine albumin-to-creatinine ratio | 180 mg/g | <30 mg/g |
| Total cholesterol | 242 mg/dL | <200 mg/dL |
| LDL cholesterol | 148 mg/dL | <100 mg/dL (diabetic goal) |
| HDL cholesterol | 36 mg/dL | >40 mg/dL |
| Triglycerides | 290 mg/dL | <150 mg/dL |
| CBC | Within normal limits | -- |
Imaging/Additional Studies:
- Optical coherence tomography (OCT) right eye: Central macular thickness 412 μm (normal <300 μm), intraretinal cystic spaces and subretinal fluid consistent with center-involving diabetic macular edema (DME)
- OCT left eye: Central macular thickness 278 μm, no intraretinal fluid
- Fundus fluorescein angiography (FFA): Right eye shows extensive capillary non-perfusion in the mid-periphery, macular leakage, and microaneurysm hyperfluorescence; left eye shows mild peripheral capillary dropout
- Ultra-widefield fundus photography: Confirmed hemorrhages and IRMA distribution in all quadrants of the right eye
Clinical Image
Fundus photograph illustration demonstrating features of severe non-proliferative diabetic retinopathy including dot-blot hemorrhages, hard exudates, cotton-wool spots, and venous beading. Source: Educational illustration.
Diagnosis
Right Eye: Severe Non-Proliferative Diabetic Retinopathy (NPDR) with Center-Involving Diabetic Macular Edema (DME) Left Eye: Moderate Non-Proliferative Diabetic Retinopathy without DME
Key Diagnostic Criteria:
- Severe NPDR (Right Eye) — meets the "4-2-1 Rule": hemorrhages in all 4 quadrants, venous beading in 2+ quadrants, and IRMA in 1+ quadrant (any one criterion qualifies)
- Center-involving DME: OCT-confirmed central macular thickness >300 μm with intraretinal cystic changes
- Moderate NPDR (Left Eye): More than mild (microaneurysms only) but does not meet severe NPDR criteria
- Systemic context: Poorly controlled diabetes (HbA1c 9.8%), concurrent microvascular complications (nephropathy, neuropathy)
Treatment Plan
- Right eye — center-involving DME:
- Intravitreal anti-VEGF therapy (aflibercept 2 mg or ranibizumab 0.3 mg) as first-line treatment
- Loading phase: monthly injections for the first 5-6 months, then treat-and-extend protocol
- Repeat OCT at each visit to monitor central macular thickness
- Right eye — severe NPDR:
- Close monitoring (every 2-3 months) for progression to proliferative diabetic retinopathy (PDR)
- Consider early panretinal photocoagulation (PRP) if follow-up adherence is a concern (as per DRCR.net Protocol S, anti-VEGF is non-inferior to PRP for PDR)
- Left eye — moderate NPDR:
- Dilated fundus examination every 6 months
- OCT monitoring for DME development
- Systemic optimization (coordinate with primary care/endocrinology):
- Intensify glycemic control: add basal insulin (e.g., glargine) given HbA1c 9.8%, target HbA1c <7%
- Optimize blood pressure to <130/80 mmHg: increase lisinopril or add amlodipine
- Intensify lipid management: increase atorvastatin to 80 mg, add fenofibrate (FIELD/ACCORD Eye studies suggest benefit in DR)
- Occupational counseling: Discuss implications for commercial driving license; visual acuity and visual field requirements must be met
- Patient education: Emphasize that vision loss from diabetic retinopathy is largely preventable with glycemic control and regular screening
Key Learning Points
- The "4-2-1 Rule" classifies severe NPDR: dot-blot hemorrhages in all 4 quadrants, OR venous beading in 2+ quadrants, OR prominent IRMA in 1+ quadrant. Meeting any one of these criteria is sufficient.
- Patients with severe NPDR have a 52% risk of progressing to proliferative diabetic retinopathy within one year without treatment, underscoring the importance of close follow-up.
- Anti-VEGF intravitreal injections are the current first-line treatment for center-involving DME, replacing focal/grid laser photocoagulation.
- Diabetic retinopathy screening should begin at diagnosis for type 2 diabetes and 5 years after diagnosis for type 1 diabetes, with annual dilated fundus examinations thereafter.
- Systemic risk factor control (glycemia, blood pressure, lipids) is essential and synergistic with ophthalmic treatment in slowing DR progression.