Abstract
Purpose: :
To determine whether peripapillary circular retinal nerve fiber layer (RNFL) thickness measured by spectral-domain optical coherence tomography (SD-OCT) and Humphrey visual field (HVF) testing show agreement among patients with confirmed optic nerve head drusen (ONHD).
Methods: :
Consecutive patients referred for neuro-ophthalmology or glaucoma evaluation who received a subsequent diagnosis of ONHD were included. All included patients underwent a 360 degree peripapillary RNFL assessment using SD-OCT (Heidelberg Spectralis HRA+OCT; Heidelberg Engineering, Heidelberg, Germany) and 24-2 SITA-standard automatic perimetric examinations with the Humphrey Field Analyzer II (Carl Zeiss Meditec, Dublin, CA). The diagnosis of ONHD had been documented by B-scan ultrasonography, and patients with a clinical diagnosis of glaucoma or ocular hypertension were excluded.
Results: :
Of the 22 included eyes, 10 (45%) had global RNFL defects and 15 (68%) had HVF defects; 9 eyes (41%) had abnormalities on both tests. There were more eyes found to have HVF abnormalities but no global RNFL defect (6/22, 27%) than there were eyes with RNFL defects but normal HVF (1/22, 5%). Among eyes where both tests were abnormal, 8 (89%) eyes demonstrated complete structure-function agreement between hemifield location of RNFL defect(s) and visual field defect(s) (kappa=0.77, p=0.009). The one eye that did not show full agreement had HVF defects in both hemifields with an RNFL abnormality only inferiorly.
Conclusions: :
Eyes with both SD-OCT and HVF abnormalities show high structure-function agreement, however 27% of eyes had a HVF defect with a normal RNFL. Due to the small number of patients with ONHD and no HVF defect (5%), SD-OCT peripapillary circle scan analysis may confer only a small benefit over HVF testing alone in the evaluation of patients with known ONHD. Alternatively, some HVF abnormalities may be false positives and may not reflect underlying optic nerve damage; in this case, an abnormal RNFL detected by SD-OCT may be a more specific test for damage associated with ONHD. Further investigation is warranted.
Keywords: neuro-ophthalmology: optic nerve • optic disc • drusen