Clinical Presentation
The earliest clinical manifestations of diabetic retinopathy are microaneurysms and hemorrhages. The initial clinical signs of diabetic retinopathy include thickening of the retinal basement membrane, appearance of microaneurysms (or hypercellular outpouchings of retinal capillaries with weakened walls due to pericyte loss), and leakage of lipid and proteinaceous material (hard exudates). Signs that would lead to visual impairment include the presence of macular edema, NVD or NVE, manifestations of severe non-proliferative diabetic retinopathy (eg extensive retinal hemorrhages or microaneurysms, venous beading, and intraretinal microvascular abnormalities [IRMA]), and vitreous or preretinal hemorrhage. Typical retinal microvascular lesions of diabetic retinopathy include microaneurysms, hard exudates, IRMA, new vessels or neovascularization, hemorrhages, cotton wool spots, venous beading, and fibrous tissue.
History
In history taking, inquire about the duration of DM, past glycemic control (glycosylated hemoglobin [HbA1c] levels and compliance to medications). It also should include medical (eg obesity, renal disease, hypertension, serum lipid levels, pregnancy, neuropathy, cystic fibrosis) and ocular history (eg ocular injections, trauma, surgery) as well as current ocular symptoms of visual loss and rate of visual loss.
Physical Examination
Ophthalmologic Exam
Visual acuity determines the extent of effect in the central vision.
Slit-lamp biomicroscopy is used to examine the posterior pole and the
midperipheral posterior pole, thus assessing the presence and severity of diabetic
retinopathy. Intraocular pressure (IOP) measurement determines the presence of
glaucoma. Gonioscopy is performed to detect anterior chamber
neovascularization, particularly in cases of iris neovascularization or
elevated IOP. Dilated fundoscopy, including stereoscopic examination of the
posterior pole, may also be done. This is
considered as the gold standard for screening diabetic retinopathy. Regarding
this, the use of 0.5–1% Tropicamide and/or 2.5% Phenylephrine for pupil
dilation is considered safe and markedly increases the sensitivity of diabetic
retinopathy screening.
Diabetic Retinopathy_Initial AssesmentScreening
Regular eye examinations for diabetic retinopathy are essential for all
patients with DM with the following recommended schedule:
- In adults with type 1 DM, the initial eye exam should be done 3-5 years after the disease onset then yearly thereafter
- Adults and children with type 2 DM should have their first eye exam at the time of diagnosis then yearly thereafter
- Pregnant patients prior to conception or early in the first trimester should have eye screening for diabetic retinopathy with follow-up every 3-12 months for those with no retinopathy or mild to moderate non-proliferative diabetic retinopathy and every 1-3 months follow-up for those with severe non-proliferative diabetic retinopathy or worse
- Children with a 5-year history of type 1 DM should have their first eye exam at 9 years old, and those with a 2-year history should have it at 12 years old then yearly follow-up
Any abnormal findings during these screenings may require more frequent monitoring.
