Abstract
Purpose:
To determine the correlations between the different retinal layer thicknesses, and the aqueous flare, visual acuity (VA), and visual field scores in eyes with retinitis pigmentosa (RP)
Methods:
The medical records of 125 eyes of 64 RP patients (age: 47.5±15.2 years) were reviewed. spectral domain optical coherence tomography was used to determine the thicknesses of the fovea and thickness of the entire retina, nerve fiver layer (NFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL) and other outer layers were measured at the 1 and 2 mm superior, inferior, nasal, or temporal to the fovea. The aqueous flare was measured with a laser flare-cell meter, (FC-500, Kowa, Tokyo). The same measurements were made on 13 normal eyes of 13 age-matched controls. The correlations between the different retinal layer thicknesses, aqueous flare, VA and visual field score (scored according to residual visual field measured by Goldmann kinetic perimetry: 0~12, 0.5 step) was studied.
Results:
The entire and outer retina of the RP eyes were significantly thinner than that of normal controls (279.9±41.9 vs 330.2±11.8 µm P<0.01; 95.9±36.5 vs172.9±7.9 µm P<0.001 respectively). The NFL, GCL, and INL of RP eyes were significantly thicker than that of normal eyes (41.3±7.1 vs 27.6±2.2 µm, P<0.001; 59.3±9.7 vs 52.5±2.6 µm, P<0.01; 50.3±7.2 vs 44.4±2.3 µm, P<0.001; respectively). The aqueous flare of RP eyes was significantly higher than that of controls (7.9±3.5 vs 3.5±1.0 pc/ms, P<0.001). The thicknesses of the NFL, GCC, and INL were significantly and positively correlated with the aqueous flare (P<0.0001, P<0.05, P<0.001 respectively) and with the outer retinal thickness negatively (P<0.05). The VA (average 0.39±0.48) was significantly correlated with the foveal thickness (average 200.6±62.9 µm) (P<0.0001), and the visual field score (average 3.5±3.2) was significantly associated with outer retinal thickness positively (P<0.0001) and aqueous flare negatively (P<0.01).
Conclusions:
The thickening of the inner retinal layers may be associated with the inflammation caused by the outer retinal cell death, which is associated with loss of visual function.