Researchers found that patients with bipolar disorder to have significant thinning of the macular full retinal thickness in the center, inner temporal, inner nasal and inner inferior of the Early Treatment Diabetic Retinopathy Study areas. Twenty-three patients with bipolar disorder and 23 controls underwent retinal evaluation using swept source optical coherence tomography (SS-OCT). 

The macular ganglion cell layer was reduced in patients compared with controls. The study found no significant differences in choroidal thickness measurements. Researchers concluded that the analysis of the retinal sublayers with SS-OCT may be a useful indicator to show degeneration and monitor disease progression in bipolar disorder.