FOSPET predicts VA

Foveal outer segment/pigment epithelial thickness (FOSPET) is significantly thinner in patients with retinitis pigmentosa (RP) than in normal eyes and also shows correlation in logMAR visual acuity (VA), indicating it may be a predictor of VA in RP, according to a study published in the December 2006 issue of the American Journal of Ophthalmology.

Andre Witkin, MD from the New England Eye Center, Boston, USA and colleagues, conducted an observational case series of nine eyes of nine patients with RP and related diseases which were imaged using ultra-high resolution optical coherence tomography (UHR-OCT). Concurrently, 36 eyes of 36 normal subjects were also imaged this way. Central foveal thickness (CFT) and FOSPET were defined and measured on UHR-OCT images in all subjects and were compared between the two groups using unpaired t tests. The two thickness measurements in RP subjects were correlated with VA using Pearson correlation and linear regression.

The UHR-OCT images showed macular photoreceptor thinning in all RP subjects. The difference in CFT between the two groups was not statistically significant (p=0.103), however the difference in FOSPET was (p=0.003). VA showed some correlation with CFT (Pearson r=0.43, r2=0.187, p=0.245) and a strong correlation with FOSPET (Pearson r=0.942, r2=0.887, p<0.0001).

The researchers believe that FOSPET may represent a possible predictor of VA in patients with RP.