Acute Primary Angle Closure Structural Damage

Changes in the RNFL

Acute Primary Angle Closure Attack Does Not Cause an Increased Cup-to-Disc Ratio

Changes in Retinal Nerve Fiber Layer After Acute Primary Angle Closure: Reply

To evaluate the changes in circumpapillary vessel density (cpVD) and retinal nerve fiber layer (RNFL) thickness after an acute primary angle closure (APAC) episode. Twenty-eight patients (28 pair of eyes) with unilateral APAC and 39 normal subjects (64 eyes) were included in this prospective, observational study. cpVD as measured by optical coherence tomography angiography and RNFL thickness as measured by spectral-domain optical coherence tomography were compared at 6 weeks after an APAC episode between affected, unaffected, and normal eyes. cpVD and RNFL thickness at 1 week and 6 weeks after APAC were also compared in APAC eyes in qualified images. At 6 weeks, cpVD was significantly lower in APAC eyes (57.3% ± 6.8%), compared to fellow eyes (63.1% ± 3.5%) and control eyes (63.6% ± 3.4%) (P < 0.001). There was diffuse microvascular dropout with greater vessel density loss in the superonasal sector. APAC eyes had thinner RNFL globally and in each sector (except temporal and nasal sectors) than in fellow and normal eyes at 6 weeks. cpVD in the affected eyes was significantly greater at 1 week (56.3% ± 5.3%) than values at 6 weeks (53.5% ± 7%) (P = 0.003) but less than cpVD in the fellow eyes (62.4% ± 5.0%) (P < 0.001). RNFL thickness for the APAC eyes at 1 week (120.6 ± 18.0 μm) was greater than the analogous values for affected eyes (90.1 ± 13.2 μm; P = 0.037) and fellow eyes at 6 weeks (102.5 ± 5.7 μm; P = 0.001). Vessel density decreased over 6 weeks after an APAC episode compared with the contralateral unaffected eyes. In contrast, there was an initial increase in RNFL thickness that was followed by a subsequent decrease.

Acute Primary Angle Closure

The aim of this study is to describe the ocular and demographic features of Caucasian patients newly presenting with primary angle closure glaucoma and the proportion of workload it represents at a tertiary university hospital glaucoma service. A retrospective case notes review was conducted for all Caucasian patients newly diagnosed with narrow angles, primary angle closure, acute primary angle closure and primary angle closure glaucoma that were seen over a period of 2 years. Demographic and ocular variables were compared and statistical analysis was carried out with the paired t-test and chi-squared test. Number of primary open angle closure glaucoma and acute angle closure cases were compared with total number of new referrals to the department, new patients diagnosed with glaucoma and population numbers for the North East of Scotland. One hundred and four patients were analysed. Twenty-four (23.1%) had narrow angles, 30 (28.8%) had primary angle closure and 50 (48.1%) had primary angle closure glaucoma. Twelve (11.5%) presented with acute primary angle closure. There was no significant difference for gender, age, hypermetropia or visual acuity between groups. Primary angle closure glaucoma constituted 22.9% (50/128) of newly diagnosed glaucoma cases. Based on the 2001 Scotland census, the crude annual incidence of newly diagnosed primary angle closure glaucoma was estimated at 14.8 per 100 000 and 3.6 per 100 000 for acute primary angle closure in the over-45-year-old population. Our study confirms that primary angle closure glaucoma is uncommon in Caucasians, but not as rare as originally perceived as it makes up a fair proportion (22.9%) of glaucoma workload.

PurposeTo determine the factors associated with retinal nerve fiber layer (RNFL) loss in eyes with acute primary angle-closure (APAC), particularly focusing on the influence of the change in the anterior lamina cribrosa surface depth (LCD).MethodsAfter the initial presentation, 30 eyes with unilateral APAC were followed up at the following specific time points over a 12-month period: 1 week, 1~2 months, 2~3 months, 5~6 months, and 11~12 months. These follow-ups involved intraocular pressure measurements, enhanced depth-imaging spectral-domain optical coherence tomography (SD-OCT) scanning of the optic disc, and measurements of the circumpapillary RNFL thickness. The prelaminar tissue thickness (PLT) and LCD were determined in the SD-OCT images obtained at each follow-up visit.ResultsRepeated measures analysis of variance revealed a significant pattern of decrease in the global RNFL thickness, PLT, and LCD (all p<0.001). The global RNFL thickness decreased continuously throughout the follow-up period, while the PLT decreased until 5~6 months and did not change thereafter. The LCD reduced until 2~3 months and then also remained steady. Multivariable regression analysis revealed that symptoms with a longer duration before receiving laser peripheral iridotomy (LI) (p = 0.049) and a larger LCD reduction (p = 0.034) were significant factors associated with the conversion to an abnormal RNFL thickness defined using OCT normative data.ConclusionEarly short-term decreases in the PLT and LCD and overall long-term decrease in the peripapillary RNFL were observed during a 12-month follow-up after an APAC episode. A longer duration of symptoms before receiving LI treatment and larger LCD reduction during follow-up were associated with the progressive RNFL loss. The LCD reduction may indicate a prior presence of significant pressure-induced stress that had been imposed on the optic nerve head at the time of APAC episode. Glaucomatous progression should be suspected in eyes showing LCD reduction after the APAC remission.

Macular Thickness

Latent, acute, and chronic Leber's hereditary optic neuropathy

Assessing the treatment of angle closure

Objective To detect changes in retinal nerve fiber layer (RNFL) thickness in the first 6 months after acute primary angle closure glaucoma (APACG) attack. Methods Twenty-four subjects with a single unilateral APACG attack and 55 eyes from 55 normal subjects were included in our study. The RNFL thickness was accessed in both eyes using optical coherence tomography (OCT) within 3 days, 2 weeks, 1, 3 and 6 months after intraocular pressure(IOP) control. The RNFL thickness was compared within the attacked eyes and the fellow eyes. And at the first and last visits, the RNFL thickness was compared between normal controls and2unaffected fellow eyes. Results Comparing with the unaffected fellow eyes, the mean RNFL thickness for the attacked eyes increased significantly within 3 days ( 121.49±23.84 )μm after IOP control (P＜0.01 ). At 2 week (107.22±24.72 )μm and 1 month (93.58±18.37)μm, there was no difference between the affected eyes and the unaffected fellow eyes for the mean RNFL thickness(P=0.31 and 0.08). At 3 months (84.10±19.89)μm and 6 month (78.98±19.17)μm, the mean RNFL thickness for the attacked eyes decreased significantly (P＜0.01 ). There were significant differences for the changes of RNFL thickness in the attacked eyes among the 5 visits (P＜0.01～0.048 ). No significant difference was demonstrated comparing of the mean RNFL thickness for unaffected fellow eyes with those of the normal subjects at first and last visits(P=0.13～0.98 ). Conclusions After an APACG episode, the RNFL thickness of attacked eyes significantly increased, and then decreased over time in the first 6 months after IOP control. Key words: Optical coherence tomography; Glaucoma, closed angle; Retina; Nerve fiber

The purpose of this article is to investigate the long-term retinal nerve fiber layer (RNFL) status and determinants of RNFL thinning after an episode of unilateral primary acute angle closure (AAC).This cross-sectional study analyzed the medical records of consecutive patients with a single episode of unilateral AAC from 1999 to 2009 in Hong Kong. The peripapillary RNFL thickness was correlated with age, gender, presenting intraocular pressure (IOP), time to laser iridotomy, time to cataract extraction, follow-up duration, as well as the last IOP, vertical cup-to-disc ratio (CDR), and vision. The fellow uninvolved eye was used as a proxy comparison of RNFL loss in the attack eye.In 40 eligible patients, the mean age was 68.3 ± 8.7 years with a male-to-female ratio of 1:7. The mean presenting IOP was 49.2 ± 14.0 mm Hg and the time from presentation to laser iridotomy was 6.7 ± 6.9 days. Forty percent of subjects received a cataract extraction at 3.2 ± 2.9 years after the attack. The last IOP, CDR, and LogMAR vision were 16.0 ± 3.8 mm Hg, 0.6 ± 0.2, and 0.6 ± 0.6 LogMAR units, respectively, at 7.9 ± 2.4 years. The RNFL thickness in the attack eye (69.2 ± 19.1 μm) was 25.2 ± 17.9% thinner than the fellow eye (93.0 ± 17.8 μm) at 7.5 ± 2.9 years post-AAC. Using univariate analysis, the last vertical CDR (odds ratio [OR] = 17.2, P = 0.049) and LogMAR visual acuity (VA) (OR = 6.6, P = 0.03) were the only significant predictors for RNFL thinning whereas none of the other covariates showed significant associations (P > 0.1).At 7.5 years following unilateral AAC, the RNFL thickness was 25% thinner than the fellow eye. CDR enlargement and poor VA were the only significant predictors for RNFL loss.

To analyse retinal nerve fibre layer (RNFL) thickness in eyes with compression of the optic chiasm by a pituitary adenoma. RNFL thickness was analysed with optical coherence tomography (OCT) and compared to visual field measurements using high-pass resolution perimetry (HRP). Sixteen eyes from eight patients with pituitary adenoma were studied. All had bitemporal visual field depression caused by compression of the optic chiasm. Patients were submitted to an ophthalmic examination more than 14 months after surgery (seven patients had undergone trans-sphenoidal and one trans-cranial adenomectomy). The examination included HRP, fundus photography and measurement of the peripapillar RNFL thickness using OCT. In spite of temporal visual field depression, not all eyes showed reduced RNFL thickness by OCT. This was also true for some eyes in which RNFL was judged to be reduced on fundus photographs. Contrary to our expectations, RNFL thickness in the nasal quadrant was normal in nine of the 16 eyes. Corresponding figures for the superior, inferior and temporal quadrants were eight, six and five, respectively. The overall RNFL thickness, as measured by OCT, did not correlate well with neural capacity, which is an index of remaining retino-cortical neural channels in HRP. RNFL thickness as measured with OCT was reduced in most, but not all, eyes with temporal field depression caused by chiasmal compression. The pattern of RNFL loss did not correlate well with the visual field defect. Sensitivity of RNFL thickness measurement in OCT was low. The method has limited value in the diagnosis of pituitary tumour compression.

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The Promise of Optical Coherence Tomography Angiography in Glaucoma