Peripapillary alterations in Idiopathic Normal Pressure Hydrocephalus.

Purpose: To evaluate the peripapillary area in eyes of patients with Idiopathic Normal Pressure Hydrocephalus (iNPH) before and after shunt surgery.

Methods: Twenty iNPH patients were prospectively recruited. Enhance depth imaging-optical coherence tomography (EDI-OCT) was performed to image the peripapillary region. Using a 360-degree 3.4 mm diameter peripapillary circle scan, the peripapillary choroidal thickness (PPCT) was manually measured and compared with 20 healthy-age-matched controls. PPCT was assessed before and after at least 6 months from VP shunt surgery in 12 patients.

Results: Mean age of iNPH patients was 75 ±7.4 years, and 45% were females. Mean PPCT was increased in non-shunted iNPH patients compared to healthy individuals (113 ± 39 vs 82 ± 43 μm, p=0.026). Also, OCT scans in the peripapillary region showed a set of recurrent alterations, such as subclinical optic disc edema (ODE) (30%), choroidal folds (40%) peripapillary intraretinal cysts (30%), peripapillary atrophy (85%), peripapillary pigment epithelium alterations (45%), and pachyvessels (70%). After 79± 29 weeks from VP shunt surgery, 84% (10 out of 12) of iNPH patients presented a reduction in PPCT (111 ± 47 vs 95 ± 49, p=0.011). This reduction was associated with a subjective improvement of the neurological symptoms in 9 out of 10 of patients, and resolution of ODE (75%), intraretinal cysts (66%), and choroidal folds (20%).

Conclusions: The ophthalmological findings observed in iNPH patients may be attributed to a framework of venous overload choroidopathy. Shunt surgery relieved peripapillary choroidal congestion, leading to improvements in OCT parameters.