Changes in retinal nerve fibre layer, optic nerve head morphology, and visual field after acute primary angle closure

Abstract

Aims/Purpose To determine and correlate the long-term changes in retinal nerve fibre layer (RNFL) thickness, optic nerve head (ONH) morphology, and visual fields after a single episode of acute primary angle closure (APAC). Methods This was a cross-sectional comparative study of patients at National University Hospital (Singapore) from 2000 to 2006 after an episode of unilateral APAC. The peripapillary and macular RNFL were measured using Stratus optical coherence tomography (OCT) and ONH configuration was assessed using Heidelberg Retina Tomography (HRT)-III. Humphrey perimetry was also performed, and the presence of disc pallor was noted. APAC eyes were compared with fellow eyes as matched controls. Results Twenty-five patients were assessed at a median of 33 months (range, 11-85 months) after APAC. OCT showed that there was a reduction in the peripapillary and outer macular RNFL thickness in APAC eyes compared with controls. Humphrey perimetry revealed significantly reduced mean deviation (P ¼ 0.006) and increased pattern standard deviation (P ¼ 0.045) in APAC eyes compared with controls. HRT-III showed no difference in mean rim area, rim volume, or cup-disc ratio between APAC eyes and controls. Disc pallor was present in nine APAC eyes (36%) but was absent in fellow eyes (P ¼ 0.002), and was associated with peripapillary RNFL thinning, visual field loss, and an increased interval between the onset of symptoms and normalization of intraocular pressure (P ¼ 0.023). Conclusion APAC results in peripapillary and outer macular RNFL loss, visual field defects, and optic disc pallor, even in cases in which the ONH configuration remains unchanged.

Objective Assessment of Progression after Acute Primary Angle Closure Using HRT and GDx

“…This is in keeping with Chai et al where a reduction in rim volume was observed after a single APAC attack [13]. It is partially in keeping with the data provided by Sng CC et al where a trend of Rim Volume reduction was suggested after a single episode of APAC [21].…”

“…This result is in keeping with Sng et al where peripapillary loss of RNFL was diagnosed after a single episode of APAC [21]. Furthermore, Chew et al noted that even if cup to disc ratio did not change, there was significant thinning of the RNFL on HRT analysis 12 months after APAC [22].…”

Anterior segment morphology after acute primary angle closure treatment: a randomised study comparing iridoplasty and medical therapy

“…Acute primary angle closure (APAC) is an ophthalmic emergency and prompt treatment is necessary to reduce the rates of vision-threatening consequences 1 2. If left untreated, persistently high intraocular pressure (IOP) can lead to synechial angle damage and glaucomatous optic neuropathy 1 3.…”

“…If left untreated, persistently high intraocular pressure (IOP) can lead to synechial angle damage and glaucomatous optic neuropathy 1 3. A long duration of raised IOP has been associated with retinal nerve fibre layer thinning,4 5 significant visual field defects6 7 and disc pallor 2. Conventional treatment of APAC involves reducing the IOP with systemic and topical medications, such as acetazolamide and β-blockers, followed by laser peripheral iridotomy to relieve the pupil block 8 9.…”

Association of iris crypts with acute primary angle closure

“…Even after resolution of APAC, up to 60% of eyes have persistently raised intraocular pressure (IOP) and are associated with significant visual impairment 3 4. Traditionally, eyes with narrow anterior chamber angles are at a higher risk of APAC and imaging studies have reported multiple quantifiable angle parameters associated with angle closure 5 6.…”