Abstract
Purpose: :
To determine whether Goldmann visual field (GVF) loss is related to macular thickness detected by spectral-domain optical coherence tomography (SD-OCT) in retinitis pigmentosa (RP).
Methods: :
GVF and SD-OCT with the Heidelberg Spectralis were obtained in 81 eyes (41 patients; mean age 54, range 19-77) with a mean 29 years of night vision loss (range 1-71). 23% of eyes had cystoid macular edema (CME). Average macular thickness was calculated for 13 subfields (central, nasal, inferior, temporal, superior) within 2, 3 and 6mm areas from the fovea, and correlated to kinetic GVFs graded as fully, partially or not seen in corresponding subfields, using multilevel model regressions to account for correlations between regions and eyes. A subgroup analysis of SD-OCT measures in 12 RP patients who were able to fully detect GVF V4e in all subfields, had a mean age of 35, no CME, and shorter mean duration of night vision loss of 12 years, were compared to 23 patients with at least some subfields that were not fully seen during GVF V4e testing, and had no CME, GVFs <45°, mean age of 55, and mean night vision loss for 33 years.
Results: :
For any subfield in a typical RP subject with a given duration of visual field and night vision loss, the macular thickness was statistically significantly thinner on average by 9.8µm (95%CI:1.2,18.4; p=0.026) when the GVF III4e was partially versus fully seen in the corresponding subfield, and controlling for CME. GVF V4e did not correspond to any statistically significant differences in macular thickness when controlling for subfield, duration of vision loss and CME. Macular thickness was not significantly different when comparing GVF V4e or III4e areas that were partially versus not seen (-1.9µm;95%CI:--12.7,9; p=0.73)(-4.7µm;95%CI:-14.4,5; p=0.34), after adjusting for subfield, duration of vision loss and CME. Among subjects who fully detected the GVF V4e in all subfields, average macular thickness was not statistically significantly greater by 11.3, 5.6 and 0.5µm, in the 2, 3, and 6mm areas, respectively, when compared to subjects with some GVF loss in those areas, potentially indicating inter-individual variability and/or pending VF loss among those without current loss.
Conclusions: :
Decrease in macular thickness due to photoreceptor and RPE loss corresponds to reductions in RP patients’ ability to fully detect the GVF III4e target in corresponding subfields. SD-OCT may be used as an objective measure to help approximate the remaining central VF within but not across RP subjects.
Keywords: retinitis • imaging/image analysis: clinical • visual fields