Abstract
Purpose :
The UK Joint College Guidance advises referral of all patients with“a narrow anterior drainage angle on Van Herick testing consistent with a significant risk of acute angle closure within the foreseeable future”.1 However, recently published data do not support widespread prophylactic laser peripheral iridotomy (LPI) for primary angle closure suspects (PACS).2 This study aims to investigate the outcomes of glaucoma referrals from community optometrists specifically for narrow anterior chamber angle on Van Herick.3-5
Methods :
This retrospective study, conducted at Moorfields Eye Hospital at Bedford (UK) included all glaucoma referrals received between April 2018 – March 2019 for “narrow Van Herick” (or synonym terms) in the absence of other glaucoma-related factors, such as raised intraocular pressure and ‘suspicious’ optic discs or visual fields. Data were collected manually via electronic medical records (Medisoft). Patients were retrospectively classified as PACS, Primary Angle Closure (PAC), and Primary Angle Closure Glaucoma (PACG).6,7
Results :
We received 438 glaucoma referrals for ‘narrow angles’ alone, of which 400 (91.3%) had a full glaucoma assessment (37 did not attend; 1 could not be found). Of these 400 patients, only 45 (11.3%; 95% Confidence intervals (CI) 8.5-14.7) had an occludable angle on gonioscopy. With regard to management decisions, 194/400 patients (48.5%; 95% CI 43.6-53.4) were discharged at first visit, 116/400 (29%; 95% CI 24.8-33.6) were monitored and 90/400 (22.5%; 95% CI 18.7-26.9) received treatment: 55/400 (13.8%; 95% CI 10.7-17.5) had LPI and 35/400 (8.8%; 95% CI 6.3-12) had phacoemulsification. The 45 patients with a confirmed occludable angle were retrospectively classified: 44/400 (11%; 95% CI 8.3-14.5) PACS, 1/400 (0.3%; 95% CI <0.01-1.6) PAC, and 0 PACG. Among the 44 PACS, 34 (77.3%; 95% CI 62.8-87.3) had LPI, 6 (13.6%; 95% CI 6-27.1) had phacoemulsification and 4 (9.1%; 95% CI 3-21.7) were monitored without treatment.
Conclusions :
The diagnostic accuracy of ‘narrow Van Herick’ for occludable iridocorneal angles was found to be low. The majority of those with a confirmed occludable angle were at low risk for glaucoma (PACS). Nonetheless, most of them underwent prophylactic LPI. The guidance for glaucoma referrals needs to be reconsidered; the clinical management of angle closure also needs to move away from the widespread use of prophylactic LPI in low risk patients.
This is a 2021 ARVO Annual Meeting abstract.