Peripapillary alterations in Idiopathic Normal Pressure Hydrocephalus

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

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.

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 μ m, 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%).

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.