Abstract
Purpose: :
To measure peripapillary retinal nerve fiber layer (RNFL) thickness after acute primary angle closure (APAC) using spectral domain optical coherence tomography (SDOCT), and to correlate this with optic nerve head morphology and visual field changes.
Methods: :
This was a prospective comparative observational study of patients who had an episode of unilateral APAC from 2000 to 2006. Peripapillary RNFL thickness was measured using SDOCT (Stratus OCT, Carl Zeiss Meditec Inc, Dublin CA, USA). Confocal laser scanning ophthalmoscopy or CLSO (HRT-III, Heidelberg Engineering Inc, Vista CA, USA) of the optic nerve head and automated static white-on-white perimetry (program 24-2, SITA Standard, Humphrey Instruments, Dublin CA, USA) were also performed. Results were compared with normal fellow eyes as matched controls.
Results: :
Fourteen patients were included in this study. 5 patients were male (35.7%) and the mean age of the patients was 60.5 ± 6.6 years. Patients first presented at a mean of 1.0 ± 0.8 days (range 0.2 to 3.0 days) after the onset of APAC symptoms. Study assessments were performed at a mean of 32.9 ± 20.8 months after APAC. SDOCT showed reduced average (86.9 ± 22.2 vs. 109.8 ± 12.4 µm, p=0.0009), superior (111.3 ± 32.3 vs. 141.1 ± 19.9 µm, p=0.007) and inferior (106.8 ± 35.8 vs. 141.6 ± 23.2 µm, p=0.0007) peripapillary RNFL thickness in APAC eyes compared to controls. Perimetry showed reduced mean deviation in APAC eyes compared to controls (-4.57 ± 3.44 vs. -2.48 ± 1.37, p=0.028). CLSO of optic nerve heads showed no difference in mean rim area (1.61 ± 0.32 vs. 1.54 ± 0.30 mm2, p=0.405), rim volume (0.40 ± 0.14 vs. 0.49 ± 0.19 mm3, p=0.185) or linear cup-disc ratio (0.40 ± 0.20 vs. 0.38 ± 0.19, p=0.669) between APAC eyes and controls. Optic atrophy was found in 3 of the 4 (75%) APAC eyes with significant visual field defects (VFD).
Conclusions: :
In this prospective study, SDOCT was able to detect a reduction in RNFL thickness in APAC eyes with no loss of neuroretinal rim. RNFL changes and visual field loss after APAC may be associated with optic atrophy.
Keywords: nerve fiber layer • optic disc • visual fields