GRPU (ie, pigmentary uveitis, golden retriever uveitis) is a common, most likely inherited condition in golden retrievers that can vary in severity (see Take-Home Messages).3 In the United States, ≈5% to 25% of golden retrievers are affected.3 The hallmark of the GRPU phenotype is radially oriented pigment on the anterior lens capsule. Mildly affected patients have a small amount of radially oriented pigment deposition on the anterior lens capsule. Severely affected patients can have radial pigmentation on the lens capsule, fibrinous material in the anterior chamber, and vision- and globe-threatening complications (eg, glaucoma). Affected dogs are most often diagnosed between 4 and 8 years of age.
GRPU diagnosis should be made in golden retrievers when radial pigment is present on the anterior lens capsule, even in the absence of other findings (eg, iridal hyperpigmentation, aqueous flare).3 GRPU is not the only potential cause of uveitis, hyphema, or glaucoma in this breed. Thorough physical and ocular examinations should be supported with appropriate diagnostic testing when the diagnosis is not clear.
Although not seen in this case, uveal cysts are commonly found in patients with GRPU and are a significant risk factor for development of GRPU in golden retrievers.3 Visualization of uveal cysts is not necessary to diagnose GRPU, as only 13.3% to 42% of eyes with GRPU have this finding on examination.3 When ultrasound biomicroscopy is used, however, 100% of eyes affected with GRPU contain multiple uveal cysts.3,4 This discrepancy is because eyes with GRPU are often affected by miosis, which may prevent complete examination of the posterior chamber.
GRPU occurs almost exclusively in golden retrievers and is therefore strongly suspected to be inherited. Because of the potential for severe visual impairment and ocular pain, breeding dogs affected with GRPU is not recommended5; however, late onset (ie, 4-8 years) has led to difficulties in preventing breeding of affected dogs.