Clinical and Anterior Segment Anatomical Features in Primary Angle Closure Subgroups Based on Configurations of Iris Root Insertion

Comparison of intraocular pressure and anterior segment parameters in subjects with asymmetrical primary angle closure disease

BACKGROUND

To compare intraocular pressure (IOP) and anterior segment parameters between eyes with unilateral primary angle closure glaucoma (PACG) and their fellow eyes with primary angle closure (PAC) or primary angle closure suspect (PACS).

METHODS

Subjects underwent anterior segment imaging using 360-degree swept-source optical coherence tomography (SS-OCT, CASIA Tomey, Nagoya, Japan) and ocular investigations including gonioscopy and IOP measurement. Each SS-OCT scan (divided into 8 frames, 22.5 degrees apart) was analysed and an average was obtained for the following anterior segment parameters: iridotrabecular contact (ITC), angle opening distance (AOD750), iris thickness and curvature, anterior chamber width, depth and area (ACW, ACD and ACA) and lens vault (LV).

RESULTS

Among 132 unilateral PACG subjects (mean age: 62.91 ± 7.2 years; 59.1% male), eyes with PACG had significantly higher presenting IOP (24.81 ± 0.94 vs. 18.43 ± 0.57 mmHg, p < 0.001), smaller gonioscopic Shaffer grade (2.07 ± 0.07 vs. 2.31 ± 0.07, p < 0.001) and a greater extent of peripheral anterior synechiae (PAS, 1.21 ± 0.21 vs. 0.54 ± 0.16 clock hours, p = 0.001). PACG eyes also exhibited increased ITC, ITC area, greater LV and smaller AOD750, ACD and ACA (all p < 0.05). Using the forward stepwise regression model, an increase in 1 mmHg in presenting IOP before laser peripheral iridotomy (LPI) increases the odds of having PACG by 9% (95% confidence interval 5%-14%).

CONCLUSIONS

PACG eyes have higher presenting IOP, smaller anterior segment parameters, greater extent of PAS, and larger LV compared to their fellow eyes with angle closure. Narrower anterior chamber dimensions and higher presenting IOP before LPI may increase risk of chronic elevated IOP and glaucomatous optic neuropathy after LPI.

Glaucoma Progression After Lens Extraction in Primary Angle-closure Glaucoma According to Angle-closure Mechanism

PRCIS

Long-term prognosis of primary angle-closure was assessed after lens extraction (LE) according to different mechanisms of angle closure (AC). Patients with pupillary block (PB) had a higher probability of glaucomatous progression than patients with plateau iris configuration (PIC).

PURPOSE

The aim was to investigate and compare the clinical characteristics and long-term prognosis of primary angle-closure disease (PACD) after LE according to different mechanisms of AC.

METHODS

In this retrospective observational cohort study, 118 eyes with PACD that underwent LE (mean follow-up; 6.0±3.5 y after surgery) were included. PACD eyes were categorized into three subgroups according to their dominant AC mechanisms, determined by anterior segment optic coherent tomography obtained before LE; PB, PIC, and exaggerated lens vault (ELV). Postoperative glaucomatous progression was determined according to functional (visual field) or structural (optic disc photographs or optic coherent tomography measured retinal nerve fiber layer thickness) criteria. Univariate and multivariate logistic regression analysis was performed to determine the risk factors associated with glaucomatous progression.

RESULTS

Fifty-two, 51, and 15 eyes with PB, PIC, and ELV, respectively, were included. All eyes showed significant intraocular pressure reduction, with a greater reduction in the ELV group than in the PB group after LE (27.0% vs. 12.5%, P=0.018). Lower baseline retinal nerve fiber layer thickness [odds ratio (OR): 0.966, P=0.004] and thinner central corneal thickness (OR: 0.985, P=0.021), and the PB group (OR: 2.891, P=0.022, reference to PIC group) were significantly associated with glaucomatous progression after LE.

CONCLUSIONS

In eyes with PACD, glaucoma progression was observed following LE despite reduced intraocular pressure. The probability of progression was highest in eyes with pupil block as a mechanism of AC. Close monitoring of glaucoma in these patients is suggested.

Lens-vault analysis and its correlation with other biometric parameters using swept-source OCT

PURPOSE

To measure lens vault (LV) and to assess its correlation with various ocular parameters in healthy eyes, using for all measurements the same high-resolution swept-source optical coherence tomographer (SS-OCT).

METHODS

We prospectively recruited 67 Caucasian healthy patients whose mean age was 41.9 ± 12.4 years; only their right eye was included in the study. Data were all recorded with the ANTERION SS-OCT and comprised, for each patient, 5 consecutive measurements of LV, anterior chamber depth (ACD), lens thickness (LT), axial length (AL), white-to-white (WTW) distance, central corneal thickness (CCT), anterior chamber volume (ACV) and spur-to-spur (STS) distance.

RESULTS

Mean LV was 0.26 ± 0.23 mm (ranging from -0.24 to 0.78 mm). Data analysis revealed a statistically significant negative correlation between LV and ACD (R=-0.80, p < 0.001), AL (R = -0.36, p = 0.002), and ACV (R = -0.68, p < 0.001), and a positive correlation between LV and LT (R = 0.67, p < 0.001), and age (R = 0.53, p < 0.001). In contrast, no statistically significant correlation was found between LV and WTW (R=-0.17, p = 0.15), CCT (R = 0.11, p = 0.36) or STS (R=-0.10, p = 0.41).

CONCLUSIONS

Taking into account our findings about intra-parameter correlation levels, we believe that LV should be measured and analyzed together with other ocular parameters in clinical routine practice both for diagnosis and for some refractive surgeries.

Association of peripheral anterior synechiae with anterior segment parameters in eyes with primary angle closure glaucoma

To investigate the association of peripheral anterior synechiae (PAS) with intraocular pressure (IOP) and anterior-segment parameters in subjects with primary angle-closure glaucoma (PACG). A total of 267 subjects with PACG were recruited and underwent gonioscopy and anterior-segment optical coherence tomography (ASOCT). Customized software was used to measure ASOCT parameters, including angle opening distance (AOD750) and trabecular-iris-space-area (TISA750) at 750 µm from the scleral spur, anterior chamber depth, width, area and volume (ACD, ACW, ACA, ACV), iris thickness (IT750), iris area (IAREA), and lens vault (LV). Presenting IOP was defined as the first IOP reading before the initiation of IOP-lowering treatment. The mean age of the 267 subjects was 67.0 ± 8.9 years, 140 (52.4%) were male, and 246 (92.1%) were of Chinese ethnicity. PAS was present in 122 (45.7%) subjects, and was most frequently found in the superior quadrant (79.5%). Subjects with PAS had greater presenting IOP (28.7 ± 12.9 vs 22.4 ± 9.7 mmHg, p < 0.001), narrower AOD750 (p < 0.001), smaller TISA750 (p < 0.001), ACD (p = 0.04), ACA (p = 0.02), ACV (p = 0.01) and larger LV (p = 0.01) compared to PACG eyes without PAS. No significant differences were noted for iris parameters. A multivariate logistic regression analysis showed that higher presenting IOP (β = 0.20, p < 0.001), worse visual field mean deviation (β = - 0.20, p = 0.01) and narrower AOD750 (β = - 0.25, p = 0.03) were the only parameters that significantly correlated with the extent of PAS in clock hours. Almost one-half of the subjects with PACG demonstrated PAS; these eyes were associated with higher presenting IOP, smaller anterior segment dimensions and more severe disease.

Phacoemulsification, visco-goniosynechialysis, and goniotomy in patients with primary angle-closure glaucoma: A comparative study

OBJECTIVE

The aim of this study was to evaluate the effects of goniotomy on patients with primary angle-closure glaucoma who underwent "phacoemulsification and visco-goniosynechialysis."

MATERIALS AND METHODS

This prospective randomized clinical trial was carried out on 63 eyes of 61 patients (48-85 years) with primary angle-closure glaucoma who were enrolled. The subjects were randomly assigned into two groups. In the first group (32 eyes) and the second group (31 eyes), the patients underwent "phacoemulsification + visco-goniosynechialysis + goniotomy" and "phacoemulsification + visco-goniosynechialysis," respectively. Intraocular pressure and antiglaucoma medication were evaluated (1 week, as well as 1, 3, and 6 months after the surgery). Anterior segment optical coherence tomography parameters (Casia, Tomey, USA) and goniotomy were evaluated preoperatively and 6 months after the surgery.

RESULTS

The mean intraocular pressure lowering the effects in the "phacoemulsification + visco-goniosynechialysis + goniotomy" group was higher than that in the "phacoemulsification + visco-goniosynechialysis" group (6.93 and 4.6, respectively). Furthermore, the difference in intraocular pressure between the two groups was significant at 3 months (P = 0.014) and 6 months (P = 0.021) after the surgery. There was no difference in anterior segment optical coherence tomography findings before the intervention; however, after the intervention, the anterior segment optical coherence tomography indices were significantly different between the two groups. Moreover, the difference in "phacoemulsification + visco-goniosynechialysis + goniotomy" indices was more than the changes in the "phacoemulsification + visco-goniosynechialysis" group.

CONCLUSION

The results of this study showed that phacoemulsification + visco-goniosynechialysis + goniotomy is a more effective surgery than phacoemulsification + visco-goniosynechialysis alone in undercounted primary angle-closure glaucoma.

Effects of Choroidal Thickness on Refractive Outcome Following Cataract Surgery in Primary Angle Closure

Purpose

To identify the preoperative biometric factors, including subfoveal choroidal thickness (CT), associated with refractive outcome after cataract surgery in eyes with primary angle closure (PAC).

Methods

This study included 50 eyes of 50 PAC patients who underwent uneventful cataract surgery. Preoperatively, anterior segment parameters including anterior chamber depth (ACD) and lens vault were determined by anterior segment optical coherence tomography. Subfoveal CT was measured by spectral domain optical coherence tomography enhanced depth imaging before and at one month after surgery. Mean refractive error (MRE) was calculated as the difference in spherical equivalent between actual postoperative refraction determined one month postoperatively and that predicted using each of three IOL calculation formulas (SRK/II, SRK/T, and Haigis). Regression analyses were performed to investigate potential associations between MRE and putative factors.

Results

Mean ACD was 1.9 ± 0.4 mm, and preoperative subfoveal CT was 250.8 ± 56.9 µm. The SRK/T (MRE, 0.199 ± 0.567 diopters [D]) and Haigis (MRE, 0.190 ± 0.727 D) formulas showed slight hyperopic shift, while the SRK/II formula demonstrated a myopic shift (MRE, −0.077 ± 0.623 D) compared with that expected after cataract surgery. Mean absolute refractive error was not significantly different between formulas. Higher preoperative lens vault and shallower ACD were associated with a hyperopic shift in all formulas, but not in a statistically significant manner. Thicker preoperative subfoveal choroid was associated with a myopic shift after cataract surgery in all formulas (SRK/II: β = −0.511, p < 0.001; SRK/T: β = −0.652, p < 0.001; Haigis: β = −0.671, p < 0.001). Greater postoperative reduction of subfoveal CT was associated with a myopic shift after cataract surgery in all formulas (SRK/II: β = −0.511, p < 0.001; SRK/T: β = −0.652, p < 0.001; Haigis: β = −0.671, p < 0.001).

Conclusions

Our results indicate that preoperative subfoveal CT and the difference between pre- and postoperative subfoveal CT are significant factors for predicting refractive error after cataract surgery in PAC patients. These findings should be considered when performing cataract surgery to optimize visual outcomes.

Long-term Changes in Anterior Segment Characteristics of Eyes With Different Primary Angle-Closure Mechanisms

PURPOSE

To assess long-term changes in the anterior segment (AS) of eyes with different angle-closure mechanisms.

DESIGN

Retrospective cohort study.

METHODS

In total, 133 eyes (from 75 participants) with angle closure were enrolled. All eyes received laser iridotomy (LI) during the follow-up period. Serial anterior segment optical coherence tomography (AS-OCT) imaging was performed during a mean follow-up of 4 years. Participants were categorized into 4 groups according to angle-closure mechanisms, based on baseline AS-OCT images: pupillary block (PB), plateau iris configuration (PIC), thick peripheral iris roll (TPIR), and exaggerated lens vault (ELV). Linear mixed-effect models were applied to evaluate the longitudinal changes in AS-OCT parameters (anterior chamber depth [ACD], lens vault [LV], and angle opening distance [AOD]).

RESULTS

Forty-six eyes (35%) were classified as PB, 30 (23%) as PIC, 34 (26%) as TPIR, and 23 (17%) as ELV. The follow-up period was 41-54 months. At baseline, ACD was shallowest in ELV, followed by PB, TPIR, and PIC, in order. The PIC group showed significantly wider AOD than the other groups at baseline. ACD decreased and LV increased over time in all groups, especially in the PIC group. After LI, the angle widened in the PB and TPIR groups, but not in the PIC and ELV groups.

CONCLUSIONS

AS parameters changed differently in the 4 groups. The effects of LI on AOD also differed among groups. Identification of the angle-closure mechanism may help predict progressive changes in AS parameters in eyes with angle closure.