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K. Hirai, F. Berisha, C. L. Trempe, G. T. Feke, T. Hirose; Pattern VER and OCT in Patients With Optic Neuropathy. Invest. Ophthalmol. Vis. Sci. 2007;48(13):3758. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To correlate the anatomical findings obtained by OCT with the functional ones by the pattern reversal visual evoked response (PVER) in patients with optic neuropathy related to systemic infection (ONi) that had visual disturbances but showed very little abnormality detectable with routine ophthalmic examinations.
Eight patients diagnosed with ONi and eight age-matched controls were included in this study. All of the patients had relatively good visual acuity (mean 20/20, range 20/25-20/15) and normal macular findings. Besides the ophthalmoscopy, silt lamp examinations, and fluorescein angiogram, Stratus OCT was used to evaluate the structures of the macula and its thickness, optic nerve head parameters, and retinal nerve fiber layer (RNFL) thickness. PVER was recorded using a black and white TV monitor with a 12 cm ×12 cm stimulus field at a testing distance of 53 cm. The transient PVER (T-PVER) was obtained by 40-min visual angle checkerboard pattern stimulus with a reversal rate of 2 Hz. The P100 latency was measured from the PVER tracings. The steady-state PVER (SS-PVER) was recorded by the checkerboard pattern stimuli with visual angles of 160, 80, 40, 20 and 10 mins of arc at 13 Hz. The alignment index (AI) was determined based on the number of the peaks appearing in the SS-PVER recordings.
Patients with ONi showed significant thinning of the RNFL localized to the superior quadrant (104.±6.5µm (Mean±SE) vs. 127.8±6.54µm, p<0.022). There was no difference in C/D ratio or in macular thickness between the patients and control subjects. Spearman's rank correlation analysis revealed a significant correlation between the AI and the temporal RNFL thickness (ρ=0.77, p<0.03) in the patient group. There was also a significant negative linear correlation between temporal RNFL thickness and P100 (p<0.02). There were no correlations between PVER parameters and RNFL thickness in the control group.
The reduction of superior RNFL and normal C/D ratios in the ONi patients suggests a different pathology of the optic nerve atrophy from that of glaucoma. The compromised AI, which correlates with temporal RNFL thickness, indicates a loss of spatial tuning in the patients. The negative linear correlation between temporal RNFL thickness and P100 appears to indicate that the papillomacular bundle damage due to ONi was reflected in the PVER. The combined use of PVER and OCT is helpful in exploring the relation between function and morphology in optic neuropathy and its diagnosis.
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