• Hard exudates in theundus represent leakage of lipid and protein from incompetent vessels in the retina, choroid, or optic disc.
– Hard exudates are usually present in the outer plexiform layer of the retina but can dissect into the subretinal space as well as into other retinal layers.
Difficult to quantify
Underlying vascular diseases such as diabetes, hypertension, and dyslipidemia
Control of blood glucose, blood pressure, and blood lipid levels can reduce the risk of common causes of hard exudates, such as diabetic retinopathy, hypertensive retinopathy, retinal arterial macroaneurysm, and retinal vascular occlusion.
Increased vascular permeability allows leakage of protein and lipid into the retina.
• Numerous retinal vascular diseases can cause hard exudates, including:
– Diabetic retinopathy
– Hypertensive retinopathy
– Retinal vascular occlusion
– Retinal arterial macroaneurysm
– Radiation retinopathy
– Coats’ disease
– Capillary hemangioma of the retina (i.e., von Hippel lesion)
– Choroidal neovascularization (e.g., age-related macular degeneration)
COMMONLY ASSOCIATED CONDITIONS
Macular edema is often present with hard exudates.
• Decreased vision if hard exudates are present in the macula
• Underlying medical diseases
• Fundus examination reveals discrete, yellow–white deposits most frequently in the posterior pole.
• Can be globular, linear, circinate surrounding a leaking vessel, or large and confluent. A macular star can be seen with neuroretinitis or hypertensive retinopathy.
DIAGNOSTIC TESTS & INTERPRETATION
• Cotton-wool spots
• Myelinated nerve fiber layer
• Chorioretinal atrophy
• Hollenhorst plaque
• Crystalline retinopathy (see the Talc retinopathy chapter)
Treatment of the underlying disorder is required.
For diabetic retinopathy and diabetic macular edema, a common cause of hard exudates, treatment of the underlying macular edema with laser photocoagulation and/or injection of intraoular steroid or anti-VEGF medication can lead to resolution of the hard exudates (1,2)[C].
Submacular surgery has been used to remove massive diabetic submacular hard exudates.
• Macular edema is often associated with hard exudates.
• Patients with neuroretinitis may have an afferent pupillary defect, but this often resolves with time.
1. Larsson J, Kifley A, Zhu M, et al. Rapid reduction of hard exudates in eyes with diabetic retinopathy after intravitreal triamcinolone: Data from a randomized, placebo-controlled, clinical trial. Acta Ophthalmol 2009;87:275–280.
2. Ciardella AP, Klancnik J, Schiff W, et al. Intravitreal triamcinolone for the treatment of refractory diabetic macular oedema with hard exudates: An optical coherence tomography study. Br J Ophthalmol 2004;88:1131–1136.