Dry Eye Syndrome: Given the history of PRK surgery, dry eye syndrome is a common complication that can cause blurry and foggy vision, especially in bright light conditions. The fact that the issue is intermittent and affects only one eye, with less vivid color perception, supports this diagnosis.

Corneal Ectasia: A potential complication of PRK surgery, corneal ectasia can cause vision disturbances, including blurry vision and altered color perception. The fact that the OCT was normal does not entirely rule out this condition.
Iridocorneal Endothelial Syndrome: This condition can cause unilateral vision loss, glaucoma, and altered color perception. Although less common, it should be considered given the patient's symptoms.
Optic Neuritis: An inflammatory condition that can cause sudden vision loss, optic neuritis might be considered, especially if the patient has a history of multiple sclerosis or other autoimmune disorders.

Giant Cell Arteritis: Although rare in a 30-year-old, giant cell arteritis can cause sudden, unilateral vision loss and should be considered due to its potential for severe consequences if left untreated.
Central Retinal Artery Occlusion: A medical emergency that requires immediate attention, central retinal artery occlusion can cause sudden, painless vision loss in one eye.
Retinal Detachment: Another emergency condition, retinal detachment can cause sudden vision changes, including blurry vision and altered color perception.

Choroidal Neovascularization: A rare condition that can cause vision loss, choroidal neovascularization might be considered, especially if the patient has a history of trauma or other eye conditions.
Optic Disc Drusen: A condition that can cause vision loss and altered color perception, optic disc drusen are rare and might be considered if other diagnoses are ruled out.
Uveitis: Inflammation of the uvea can cause vision loss, blurry vision, and altered color perception. Although rare, it should be considered in the differential diagnosis.