Ocular parameters in the subgroups of angle closure glaucoma

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.

Effect of the iridocorneal angle size on the diurnal pressure profile in a glaucoma suspect cohort and patients with glaucoma

PURPOSE

To evaluate the impact of the iridocorneal angle size (ICAS) on the diurnal intraocular pressure (IOP) in patients with suspected glaucoma (SG).

METHOD

Patients with any eye-pressure lowering medication or previous ocular surgery were excluded. In a retrospective study set, diurnal IOP profiles of 120 patients (205 eyes) within a 48-h period were analysed by regression analysis. Of those eyes, 44 were diagnosed to have glaucoma. The remaining eyes were used as healthy control group (HCG).

RESULTS

The overall mean IOP was 15.63 mmHg ± 2.72 mmHg and mean ICAS was 23.92° ± 4.74°. In the glaucoma cohort, mean IOP was 18.77 ± 1.86 mmHg and mean ICAS was 25.02° ± 4.96°. In the HCG, mean IOP was 14.77 ± 2.25 mmHg and mean ICAS was 23.62° ± 4.64°. In the total cohort, as well as in the subgroups (HCG or glaucoma), regression analysis showed no significant impact even of the minimum ICAS, which was larger than 10°, on average (P = 0.89), maximum (P = 0.88), and range of IOP (P = 0.49) within 48 h. The difference between glaucoma cohort and HCG cohort was significant in terms of IOP (P < 0.001), but not for minimum ICAS (P = 0.07). Chi-square test showed no increase in prevalence of IOP peaks of  > 21 mmHg within 48 h in eyes with an angle between 10° and 20° (P = 0.18).

CONCLUSION

An ICAS of larger than 10° in HCG or glaucoma patients with an open-angle does not influence the minimum, average, maximum or range of IOP. Additionally, an angle size larger than 10° does not allow the prediction of IOP changes in these two cohorts.

Association of body mass index and PXDNL gene variants with acute primary angle closure in southern Chinese population

This study aimed to evaluate the association of body mass index (BMI) and the weight-related gene, peroxidasin-like (PXDNL), with acute primary angle closure (APAC) and primary angle-closure glaucoma (PACG) in southern Chinese population. Total 4700 study subjects (1024 APAC, 781 PACG, and 2895 control subjects) with complete ophthalmic examinations were enrolled into this study. The association of BMI with APAC, PACG and ocular biometric parameters was evaluated. Three PXDNL missense variants were genotyped by TaqMan assay, and their association with APAC and PACG was also investigated. Multivariable logistic regression analysis showed that BMI and body weight were significantly associated with both APAC and PACG (P < 0.01). Multiple linear regression analysis demonstrated that each 1 kg/m2 increased in BMI was associated with 0.038 mm increase in axial length, 0.018 mm increase in central anterior chamber depth, 0.002 mm increase in lens position, 0.012 mm increase in corneal diameter and 0.014 mm decrease in lens thickness among the APAC subjects (P < 0.001), but not with PACG. Genetic association analysis identified that PXDNL rs11985241-rs16916207 CT haplotype conferred a higher risk to APAC (OR = 1.25, P = 0.004) than the TG haplotype, but not with PACG. The APAC subjects carrying the rs11985241 C or rs16916207 T alleles showed significantly lower weight than those carrying the corresponding protective alleles. In summary, this study revealed that lower BMI could be associated with higher risk of APAC. PXDNL could be a new associated gene for APAC.

Lens factor as an underlying mechanism in primary angle closure with gonioscopically-visualized ciliary body processes

PURPOSE

To compare the differences in anterior segment parameters between eyes with primary angle closure (PAC) with and without gonioscopically-visualized ciliary body processes (CBP).

STUDY DESIGN

Prospective, observational, comparative clinical study.

METHODS

Detailed ocular examinations and gonioscopy were performed in 89 eyes of 89 patients with PAC to determine the visibility of the CBP. Anterior chamber depth (ACD), anterior chamber width, lens thickness (LT), lens vault (LV) and pupil diameter were determined using ultrasound biomicroscopy. The lens-axial length factor (LAF) and relative lens position (RLP) were calculated. All parameters were compared between eyes with and without gonioscopically visible CBP (PAC+CBP and PAC-CBP groups) after adjusting for age and gender. The association of the parameters with visible CBP was analyzed by univariate logistic regression analysis.

RESULTS

PAC+CBP group included 41 eyes and the PAC-CBP group, 48 eyes. The axial length and ACD were statistically significantly smaller (p = 0.009 and p = 0.005, respectively) and LT, LV and LAF were statistically significantly greater (p = 0.03, p = 0.008 and p = 0.004, respectively) in the PAC+CBP group. In the PAC eyes with glaucoma, the LT, LV and LAF were statistically significantly greater in the PAC+CBP group (p = 0.02, p = 0.001 and p = 0.02, respectively). The LAF had the strongest association with visible CBP in the regression analysis (Odds ratio = 141.70, p = 0.002).

CONCLUSION

Gonioscopical visualization of ciliary processes may suggest that anterior segment crowding, especially lens factor is the underlying mechanism in PAC. It may provide a practical gonioscopic examination method for predicting the predominant pathophysiology of PAC.

The Structural Layers of the Porcine Iris Exhibit Inherently Different Biomechanical Properties

Purpose

The purpose of this study was to isolate the structural components of the ex vivo porcine iris tissue and to determine their biomechanical properties.

Methods

The porcine stroma and dilator tissues were separated, and their dimensions were assessed using optical coherence tomography (OCT). The stroma underwent flow test (n = 32) to evaluate for permeability using Darcy's Law (ΔP = 2000 Pa, A = 0.0391 mm2), and both tissues underwent stress relaxation experiments (ε = 0.5 with initial ramp of δε = 0.1) to evaluate for their viscoelastic behaviours (n = 28). Viscoelasticity was characterized by the parameters β (half width of the Gaussian distribution), τm (mean relaxation time constant), E0 (instantaneous modulus), and E∞ (equilibrium modulus).

Results

For the stroma, the hydraulic permeability was 9.49 ± 3.05 × 10-6 mm2/Pa · s, and the viscoelastic parameters were β = 2.50 ± 1.40, and τm = 7.43 ± 4.96 s, with the 2 moduli calculated to be E0 = 14.14 ± 6.44 kPa and E∞ = 6.08 ± 2.74 kPa. For the dilator tissue, the viscoelastic parameters were β = 2.06 ± 1.33 and τm = 1.28 ± 1.27 seconds, with the 2 moduli calculated to be E0 = 9.16 ± 3.03 kPa and E∞ = 5.54 ± 1.98 kPa.

Conclusions

We have established a new protocol to evaluate the biomechanical properties of the structural layers of the iris. Overall, the stroma was permeable and exhibited smaller moduli than those of the dilator muscle. An improved characterization of iris biomechanics may form the basis to further our understanding of angle closure glaucoma.

Risk of acute angle-closure and changes in intraocular pressure after pupillary dilation in patients with diabetes

BACKGROUND

To evaluate the risk of AAC and intraocular pressure (IOP) changes in diabetic patients after pupil dilation.

METHODS

This cross-sectional study enrolled 2,287 diabetic patients among community residents in Guangzhou, China. All participants underwent routine pupil dilation unless they had a history of glaucoma. IOP was measured using a non-contact tonometer before and one hour after pupil dilation with tropicamide 0.5% and phenylephrine 0.5% eye drop. The proportion of AAC and changes in IOP after pupil dilation were evaluated.

RESULTS

Only one of the 2,287 participants (0.04%) with diabetes developed post-dilation AAC. The mean pre and post-dilation IOP in the right was 16.1 ± 2.7 and 16.5 ± 2.8 mmHg (P < 0.001); mean pre and post-dilation IOP in the left was 16.5 ± 2.7 and 16.8 ± 2.8 mmHg (P < 0.001). Sixty-one participants (2.7%) showed an increase in IOP ≥ 5 mmHg and 25 participants (1.1%) showed a post-dilation IOP > 25 mmHg, including 11 participants (0.5%) who had both an increase in IOP ≥ 5 mmHg and post-dilation IOP > 25 mmHg. Lower pre-dilation IOP (OR = 0.827; 95% CI, 0.742-0.922; P = 0.001) and shallower anterior chamber depth (ACD) (OR = 0.226; 95% CI, 0.088-0.585; P = 0.002) were significant risk factors for an increase in IOP ≥ 5 mmHg in multivariate logistic regression analysis.

CONCLUSIONS

The risk of developing AAC after pupil dilation in diabetic patients was very low. Lower pre-dilation IOP and shallower ACD are risk factors for increased post-dilation IOP.

Factors defining the intraocular pressure-lowering effect of phacoemulsification and laser peripheral iridotomy in patients with primary angle closure : Factors defining IOP lowering effect of PE and LPI in PAC

To identify whether gonioscopic ciliary body visibility and factors including anterior chamber depth (ACD), axial length (AL), acute attack history, and preoperative intraocular pressure (IOP) had any effect on IOP decrease in primary angle closure (PAC) and primary angle-closure glaucoma (PACG) after phacoemulsification (PE) and/or laser peripheral iridotomy (LPI). This retrospective-design study was conducted with 81 eyes with PAC and PACG; 33 eyes whose IOP was controlled with LPI and PE constituted group 1, and 48 eyes whose IOP was controlled using LPI alone comprised group 2. The effects on preoperative and last-visit IOP levels, ciliary body visibility, ACD, AL, and acute attacks were analyzed. Eyes within the groups were similar in AL, ACD, and preoperative IOP except for acute attack history, which was found to be higher in group 1. For group 1, none of the factors was found to have a differentiative effect on IOP decrease after PE, except eyes with preoperative IOP > 21 mm Hg, which had significantly more IOP reduction. For group 2, no difference was found in ciliary body visibility, and higher or lower ACD. However, eyes with AL ≥ 22 mm, positive acute attack history, and higher preoperative IOP were associated with significantly better IOP reduction. We found no relationship between ciliary body visibility and an IOP-reducing effect of PE and LPI. Although we found PE effective in IOP reduction in all eyes, we determined LPI to have a lesser IOP-reducing effect in eyes with IOP ≤ 21 mm Hg and AL < 22 mm.

Can ultrasonic biometric indices with optimal cut-offs be a potential screening tool for primary angle closure disease? A case-control study

BACKGROUND/OBJECTIVES

Despite a significant disease burden and potential to cause blindness, primary angle closure disease (PACD) does not have a population-based screening programme. Biometric indices using ultrasound A-scan is a potential tool for glaucoma case-detection. Given that genetic and environmental factors influence these parameters and paucity of data on their discrimination thresholds in Indian populace, we conducted a matched case-control study to determine the biometric indices and their discrimination thresholds associated with PACD.

METHODS

We studied 172 eyes of 86 participants (43 cases; 43 controls). We compared the following biometric parameters of cases (PACD, occludable angle ≥180° ± raised intraocular pressure) with age and gender-matched controls (1:1): Anterior chamber depth (ACD), lens thickness (LT), axial length (AXL), lens position (LP), relative lens position (RLP), lens axial factor (LAF), simple crowding value (Cs), ACD/AXL). We performed conditional logistic regression (to identify factors associated with PACD) and Receiver operating characteristic (ROC) analysis (to determine discrimination thresholds).

RESULTS

Reduced ACD (Adj OR 0.01; 95% CI: 0.0003-0.15, p < 0.001) and increased LT (Adj OR 10.3; 95% CI:2.42-43.93, p < 0.001) were associated with PACD. On ROC analysis, ACD, Cs, and ACD/AXL had optimum sensitivity/specificity at ≤3.015, ≥0.056 and ≤0.1303, respectively. ACD (88.4%) and Cs (94.2%) had highest sensitivity and specificity, respectively.

CONCLUSION

Ultrasonic biometric parameters differed significantly between PACD and controls. ACD and Cs (at discrimination thresholds of ≤3.015 mm and ≥ 0.056, respectively) using ultrasound A-scan could be a potential tool for PACD case-detection that requires evaluation of its diagnostic yield and cost-effectiveness.

The inflammatory cytokine profiles and ocular biometric characteristics of primary angle-closure glaucoma

OBJECTIVE

To investigate the pathogenesis of primary angle-closure disease (PACG) by measuring the anatomical structures of the anterior and posterior segments of the eye and inflammatory markers in the peripheral blood.

METHODS

This case-control study enrolled patients diagnosed with acute PACG (APACG) and chronic PACG (CPACG). It also enrolled control subjects without PACG. The anterior and posterior anatomical features were measured in all study participants. The levels of interleukin (IL)-6, tumour necrosis factor-α and the neutrophil-to-lymphocyte ratio (NLR) in the peripheral blood were measured.

RESULTS

This study analysed a total of 99 eyes: 34 eyes from 34 patients with APACG, 28 eyes from 28 patients with CPACG and 37 eyes from 37 control patients with senile cataract. The axis length, corneal diameter, anterior chamber depth and anterior chamber volume were significantly smaller in the APACG and CPACG groups compared with the controls. The level of IL-6 in the peripheral blood of patients with PACG was significantly lower than that of the controls. The NLR in the peripheral blood of patients with PACG was significantly greater than that of the controls.

CONCLUSIONS

Changes in the ocular anatomy and some inflammatory markers might be involved in the pathogenesis of PACG.

A comparison of lens parameters in patients with various subtypes of primary angle-closure disease and the normal population: A prospective study

Purpose:

To assess the role of lens parameters in the detection and progression of primary angle-closure disease (PACD) by combining A-scan and A-scan optical coherence tomography (AS-OCT) parameters.

Methods:

A cross-sectional study was conducted in a tertiary health-care center in eastern India. A total of 91 study subjects including cases and controls were included in the study. The parameters studied were lens thickness (LT), lens axial factor (LAF), relative lens position (RLP), and lens vault (LV). Anterior chamber depth (ACD) and axial length (AL) were also analyzed using A-scan.

Results:

The LT was significantly more in all subtypes of PACD (from 4.24 ± 0.84 to 5.02 ± 0.18 mm) than in controls (4.04 ± 0.46 mm; P < 0.01). Similarly, LAF was significantly less among all subtypes of PACD compared to controls (P < 0.001). The RLP, calculated using the formula (ACD + 0.5 LT)/AL × 10, showed no significant difference (P > 0.05) between various study groups. The LV in acute angle-closure glaucoma (AcCG) patients was significantly higher compared to the control population (P < 0.01). Ocular parameters like ACD decreased, whereas LT and LAF increased from normal through primary angle closure (PAC) to primary angle-closure glaucoma (PACG). Logistic regression analysis found a significant association between a decrease in ACD and an increased risk of PACG (P-value was 0.0001) and an increase in LT and LAF with increased risk of PACG (P = 0.040 and P = 0.006, respectively).

Conclusion:

Inclusion of lens parameter assessment in the workup of a patient with PACD helps in detection and close monitoring of the progression from suspected to disease state.

Comparison of Anterior Chamber Depth with Posture Change Between Primary and lens-induced Angle Closure Glaucomas

Purpose: To compare the changes in central anterior chamber depth between supine and sitting positions using an ultrasound biomicroscope among acute angle closure glaucoma, lens-induced angle closure glaucoma, and normal groups.Methods: This study included 18, 13, and 29 individuals with acute angle closure glaucoma, lens-induced angle closure glaucoma, and control, respectively. The central anterior chamber depth, trabecular iris angle, corneal curvature, and axial length were measured in the sitting and supine positions.Results: The central anterior chamber depth in the supine and sitting positions were 1.61 ± 0.47 mm and 1.55 ± 0.46 mm in the acute angle closure glaucoma, which were significantly smaller than those in the normal group (2.48 ± 0.49 mm and 2.47 ± 0.50 mm) (p = 0.01 and p = 0.009, respectively). In lens-induced angle closure glaucoma, the central anterior chamber depth in the supine and sitting positions were 1.65 ± 0.84 mm and 1.52 ± 0.82 mm, respectively, which were significantly smaller than those in the normal group (p < 0.001 for both). The absolute change in central anterior chamber depth with posture alteration was significantly larger in both acute angle closure glaucoma (0.15 ± 0.09 mm) and lens-induced angle closure glaucoma (0.25 ± 0.11 mm) than in the normal control (0.09 ± 0.08 mm) (p = 0.011, p < 0.001, respectively). The largest amount of change was shown in the lens-induced angle closure glaucoma (p = 0.012). The absolute change in anterior chamber angle with posture change wa not significantly different between the groups (p = 0.165).Conclusions: Compared to the control group, the central anterior chamber depth was smaller in both glaucoma groups. The absolute change in the anterior chamber depth with posture was significantly larger in the lens-induced angle closure glaucoma than in acute angle closure glaucoma.

Anterior Chamber Angle Changes in Primary Angle-closure Glaucoma Following Phacoemulsification Versus Phacotrabeculectomy: A Prospective Randomized Clinical Trial

PRCIS

We used anterior segment optical coherence tomography to investigate anterior chamber angle in primary angle-closure glaucoma (PACG) eyes following phacoemulsification and phacotrabeculectomy. Angle widening was significantly greater after phacoemulsification up to 6 months after the surgery.

PURPOSE

To compare anterior chamber angle following 2 common surgeries for PACG.

METHODS

One hundred ten glaucoma patients were evaluated in this single center, prospective, randomized clinical trial. Those with concomitant PACG and senile cataract and without a history of ocular surgery, trauma, or chronic miotic use were recruited. Monocular patients were also excluded. Finally, 52 eligible subjects were randomly assigned to phacoemulsification ("Phaco" group, 25 eyes) or phacotrabeculectomy ("Combined" group, 27 eyes) surgeries. A swept-source, anterior segment optical coherence tomography device (CASIA SS-1000 OCT) was used to image the anterior segment. Mask graders used the images to measure the following parameters before and 1 week, 1 month, and 6 months after surgery: angle opening distance at 500 µm, trabecular iris surface area at 500 µm, and trabecular iris angle at 500 µm.

RESULTS

There was no significant difference between study groups regarding best-corrected visual acuity, intraocular pressure (IOP), and the number of glaucoma medications in preoperative or postoperative visits (P>0.076). Also, the measured angle parameters were not statistically significantly different between the 2 groups before surgery (P>0.123). After surgery, all measured parameters were significantly increased in both groups (P<0.0001). At the 6-month follow-up, nasal angle opening distance at 500 µm was 0.383±0.027 vs. 0.349±0.017, trabecular iris surface area at 500 µm was 0.141±0.007 vs. 0.125±0.005, and trabecular iris angle at 500 µm was 40.1±12.9 vs. 34.6±3.1 in Phaco and Combined groups, respectively (P<0.0001 for all).

CONCLUSIONS

Anterior chamber angle widening by anterior segment optical coherence tomography was observed in PACG patients following surgery and was significantly greater after phacoemulsification compared with combined phacotrabeculectomy at all time points. Similar IOP and medication burden were noted for up to 6 months as secondary outcomes. The contribution of angle changes to the IOP-lowering effect of phacoemulsification in PACG eyes needs further study.

Anterior Lens Curvature Matters in the Course of Primary Angle Closure: An Analysis Based on Ultrasound Biomicroscopic Imaging

Purpose. To evaluate the effect of anterior lens curvature in primary angle closure (PAC) and find additional anatomical features of crystalline lens that may predispose primary angle closure to the acute course. Methods. 435 eyes (263 subjects) were enrolled in this study. Four groups of eyes were included based on angle configurations and clinical features: (i) acute primary angle closure (APAC, 140 eyes); (ii) chronic primary angle closure (CPAC, 116 eyes); (iii) primary angle closure suspect (PACS, 84 eyes); and (iv) normal controls (95 eyes). All patients underwent thorough ophthalmic exams including applanation tonometry, gonioscopy, low-coherence interferometry, and ultrasound biomicroscopic imaging. Based on the panoramic anterior segment images from ultrasound biomicroscopic imaging measurements, the radius of anterior lens curvature (ALR) was calculated using the least-squares curve fitting technique. ALR, in addition to axial length (AL), anterior chamber depth (ACD), and lens thickness (LT), was compared among different groups using univariate and multivariate analysis with mixed effects linear model. Results. APAC, CPAC, and PACS groups all had steeper ALR, shorter AL, shallower ACD, and thicker LT than normal control group. ACD and LT further differ between APAC and CPAC or PACS eyes. Moreover, a steeper ALR was also found in the APAC group as compared to CPAC, PACS, and normal control groups. Conclusions. A steeper ALR may predispose the acute attack of PAC. In addition to the relative lens position and size, lens curvature is another variable that contributes to the pathophysiological mechanisms of primary angle closure.

Novel Discoveries of Anterior Segment Parameters in Fellow Eyes of Acute Primary Angle Closure and Chronic Primary Angle Closure Glaucoma

Purpose

To investigate the biometric differences of anterior segment parameters between fellow eyes of acute primary angle closure (F-APAC) and chronic primary angle closure glaucoma (F-CPACG) to get information about differences between APAC and CPAC.

Methods

Patients with F-APAC and F-CPACG without prior treatment were enrolled from glaucoma clinics. Parameters were measured on ultrasound biomicroscopy images, including pupil diameter, lens vault (LV), anterior chamber depth, anterior chamber width, iris area, iris thickness (IT 750 and 2000), angle-opening distance (AOD 500 and 750), trabecular-iris space area (TISA 500 and 750), trabecular iris angle (TIA 500 and 750), trabecular–ciliary angle, and ciliary process area. Multivariate logistic regression analysis was performed to determine the most important parameters associated with F-APAC compared with F-CPACG.

Results

Fifty-five patients with APAC and 55 patients with CPACG were examined. The anterior chamber depth, IT 750, AOD 750, trabecular iris angle 750, and trabecular–ciliary angle were smaller, and LV and ciliary process area were greater in F-APAC as compared with F-CPACG (P ≤ 0.01). Multivariate logistic regression showed that thinner IT 750, smaller AOD 750, and larger LV were significantly associated with F-APAC (P < 0.01). IT 750 (area under the curve, 0.703) performed relatively better than AOD 750 (area under the curve, 0.696) in distinguishing F-APAC from F-CPACG, with the best cutoff of 0.404 mm and 0.126 mm, respectively.

Conclusions

Compared with F-CPACG, F-APAC had thinner peripheral iris, narrower anterior chamber angle, shallower anterior chamber depth, greater LV, larger and anteriorly positioned ciliary body. IT 750, AOD 750, and LV played important roles in distinguishing eyes predisposed to APAC or CPAC.

The anterior and posterior biometric characteristics in primary angle-closure disease: Data based on anterior segment optical coherence tomography and swept-source optical coherence tomography

Purpose:

Obtaining a better understanding of the pathogenesis of primary angle-closure disease (PACD) still requires studies that provide measurements of anterior and posterior biometric characteristics together and that assess the relationship between them.

Methods:

In total, 201 eyes were enrolled in this cross-sectional study: 50 normal controls, 49 primary angle-closure suspect (PACS), 38 primary angle closure (PAC), and 64 primary angle-closure glaucoma (PACG) eyes. The anterior and posterior structural features were measured by anterior segment optical coherence tomography and swept-source optical coherence tomography.

Results:

All PACD groups had smaller anterior chamber depth (ACD), anterior chamber area (ACA), anterior chamber volume (ACV), angle opening distance at 750 μm from the scleral spur (AOD750), trabecular–iris space area at 750 μm from the scleral spur (TISA750), and angle recess area (ARA), as well as a larger lens vault (LV), than controls (all P < 0.001). The PACS and PAC groups had thicker iris thickness at 750 μm from the scleral spur (IT750) than controls (P = 0.017 and P = 0.002, respectively). Choroidal thickness (CT) was not statistically different among normal, PACS, PAC, and PACG eyes. Univariate and multivariate linear regression analysis revealed a significant association between thinner IT750 and increased CT in PACD eyes (P = 0.031, univariate analysis; P = 0.008, multivariate analysis).

Conclusion:

Thinner iris thickness was associated with increased CT in PACD eyes; however, the underlying mechanism needs further investigation.

Long-term outcomes of prediction error after combined phacoemulsification and trabeculectomy in glaucoma patients

Background

To investigate long-term outcomes of prediction error after phacotrabeculectomy and to determine risk factors that may cause unstable prediction error after phacotrabeculectomy in glaucoma patients.

Methods

A total 120 eyes of 120 patients who had underwent uncomplicated phacotrabeculectomy (combined group) or phacoemulsification (phaco-only group) were included. Best-corrected visual acuity (BCVA), intraocular pressure (IOP) were measured before and after surgery, and anterior segment parameters including anterior chamber depth (ACD), lens vault (LV), and anterior vault (AV) measured using anterior-segment optical coherence tomography were compared between the two groups. The mean absolute error (MAE) at 3, 6, 12, and 24 months postoperatively were compared. Risk factors associated with unstable prediction error (MAE ≥ 0.5) were investigated in the combined group.

Results

In both groups, BCVA was improved and IOP was decreased significantly. MAE at 3, 6, 12, 24 months postoperatively were not significantly different between two groups. The risk factors for unstable prediction error after 12 months of phacotrabeculectomy were old age and LV. Whereas, the only factor predicting unstable prediction error after 24 months of phacotrabeculectomy was LV. The cut-off value of LV for predicting unstable refractive error analyzed by the ROC curve was 0.855 mm.

Conclusions

Phacotrabeculectomy may be an effective treatment with stable long-term outcomes of prediction error similar to phacoemulsification in patients with glaucoma. However, elderly patients or patients with large LV may be predisposed to unstable prediction error after phacotrabeculectomy.

Quantification of Retinal Microvascular Density Using Optic Coherence Tomography Angiography in Primary Angle Closure Disease

Purpose: To evaluate the microvascular density of the peripapillary and parafoveal areas of the eyes with primary angle closure disease (PACD) using optical coherence tomography angiography (OCTA).Materials and methods: An observational study was conducted with 76 PACD patients (29 eyes with primary angle closure suspect, 22 eyes with primary angle closure [PAC], and 25 eyes with primary angle closure glaucoma [PACG]) and 27 control eyes. OCTA was performed for all subjects to acquire a 4.5 × 4.5 mm scanning area centered on the optic discs and a 3 × 3 mm parafoveal cubes. Peripapillary and parafoveal vessel density (VD) were compared between these four groups, and the relationship between VD values and structural and functional changes was evaluated.Results: Among all four groups, the peripapillary VD of the PACG eyes was the lowest in all six sections (all P < .01), while the parafoveal VD was lower than that of the normal group only in the average, superior, and inferior areas (all P < .05). The PAC group had lower peripapillary VD than the normal group (62.6[55.2-67.4] vs. 66.7[54.7-69.3], P = .01), while their retinal nerve fiber layer (RNFL) and ganglion cell complex thickness were not significantly different than those of the control group (all P > .05). In addition, the stages of PACD, visual field mean deviation, and RNFL thickness were shown to be predictors of the peripapillary VD in the multiple linear regression analysis.Conclusions: The PAC eyes had lower peripapillary VD than normal eyes when their RNFL and GCC thickness did not differ. This suggests that a reduction in retinal VD may occur before structural loss in PAC eyes. Retinal VD measurement may be a useful tool for the assessment of PACD.

Morphologic Features of Crystalline Lens in Patients with Primary Angle Closure Disease Observed by CASIA 2 Optical Coherence Tomography

Purpose

To investigate the morphologic features of crystalline lens in primary angle closure disease (PACD) by the swept-source anterior segment optical coherence tomography.

Methods

This cross-sectional observational study included 125 consecutive eyes from 125 patients who underwent anterior segment optical coherence tomography (CASIA 2, Tomey, Nagoya, Japan) examination, including 38 eyes of normal controls, 57 eyes of PAC suspects (PACS), and 30 eyes with PAC or PAC glaucoma (PACG). Crystalline lens parameters were compared among the three groups. Spearman correlation analysis and multiple linear regression models were performed to evaluate the relationships between the lens parameters and related factors.

Results

Significant differences were found for anterior chamber depth, axial length, iridotrabecular contact index, lens vault, lens thickness (all P < 0.001), the anterior radius curvature of lens (normal vs PACS vs PAC/PACG: 9.35 ± 1.29 mm vs 8.40 ± 0.62 mm vs 8.12 ± 0.54 mm; P < 0.001), lens decentration (normal vs PACS vs PAC/PACG: 0.14 ± 0.07 mm vs 0.19 ± 0.09 mm vs 0.22 ± 0.12 mm; P = 0.004), and tilt (normal vs PACS vs PAC/PACG: 4.9 ± 1.0° vs 5.3 ± 1.2° vs 5.8 ± 1.8°; P = 0.033) among the three groups. The multivariate regression analysis found that both iridotrabecular contact index and the stage of the PACD were negatively correlated with the anterior radius curvature of lens, positively correlated with lens thickness and decentration after adjustment for age, sex, and axial length (all P < 0.05).

Conclusions

Steep anterior curvature and decentration of the crystalline lens may be another anatomic characteristic of eyes with PACD. These findings support that the crystalline lens morphologic features may have great contribution to the development of PACD.

Peripheral anterior chamber depth and screening techniques for primary angle closure disease in community elderly Chinese

Background

To investigate the distribution of peripheral anterior chamber depth (ACD) and the relationship between peripheral ACD and gonioscopy compared to other ocular parameters for primary angle closure disease (PACD) screening. We performed a population-based survey in Pudong New District of Shanghai, China, in 2011.

Methods

Cross-sectional study. Adults 50 and older were enrolled from a population-based study using cluster random sampling in Pudong New District, Shanghai. Remote ocular screening was performed with digital anterior eye structure photography. Van Herrick measurements were used to evaluate the peripheral ACD, the depth of the peripheral anterior chamber, and corneal thickness (CT), and the ACD to CT ratio was calculated. Subjects with peripheral ACD less than 0.5 CT were made follow-up appointments for clinical examination with gonioscopy. Receiver operating characteristic curves (ROC) were generated to show the performance of different tests in screening for primary angle closure disease (PACD).

Results

Two thousand five hundred twenty-eight adults participated in the study with 91 patients diagnosed with PACD. Two thousand four hundred sixty-three subjects had valid data in the right eye available for analysis. The mean peripheral ACD values for men and women were significantly different: 1.04 ± 0.46 (range 0.11–2.93) CT and 0.87 ± 0.41 (range 0.12–2.96) CT respectively (t = − 4.18; P<0.0001). Multivariate logistic regression analysis reveals that peripheral ACD declined by 0.31 CT (P < 0.0001) per diopter of SE and was 0.19 CT (P < 0.0001) shallower in women than in men (r2 = 0.1304, P < 0.0001). Peripheral ACD performed best in screening for PACD.

Conclusions

Peripheral ACD measurement is recommended for PACD screening in community elderly Chinese.

Changes in Intraocular Pressure and Angle Structure after Dilation in Primary Angle-Closure Suspects with Visually Significant Cataract

PURPOSE

To evaluate the safety of pupillary dilation in primary angle-closure suspects (PACS) with concurrent visually significant cataract (VSC), to identify risk factors associated with elevated intraocular pressure (IOP), and to describe changes in anterior segment anatomy after pupillary dilation.

DESIGN

Prospective study.

PARTICIPANTS

Patients with PACS and VSC and no prior laser or intraocular surgery were recruited. Visually significant cataract was defined as best-corrected visual acuity ≤ 20/40 due to cataract.

METHODS

Subjects' eyes were dilated with 0.5% tropicamide and 0.5% phenylephrine hydrochloride. A standardized eye examination, biometry, and swept-source OCT (SS-OCT) were performed before dilation. Intraocular pressure and SS-OCT were repeated 1, 4, and 6 hours postdilation (PDH1, PDH4, and PDH6, respectively). All parameters were compared between time points before and after dilation using paired t test. Linear regression models were used to determine the risk factors associated with postdilation IOP changes.

MAIN OUTCOME MEASURES

Change in IOP and SS-OCT parameters from baseline.

RESULTS

Seventy-eight eyes from 78 patients were included, with 78, 66, and 12 patients completing the study at PDH1, PDH4, and PDH6, respectively. Mean IOP increased from 14.8 ± 2.6 mmHg at baseline to 15.5 ± 3.5 mmHg at PDH1 (P = 0.03) and decreased to 14.9 ± 3.1 mmHg at PDH4 (P = 0.09). Four patients (5.13%) and 3 patients (3.85%) had an increase in IOP ≥ 5 mmHg at PDH1 and PDH4, respectively. Two patients (2.56%) and 1 patient (1.28%) had an increase in IOP ≥ 8 mmHg at PDH1 and PDH4, respectively. None developed acute primary angle-closure during the observation period. Almost all anterior chamber parameters showed a significant increase after dilation at PDH1 and PDH4, except lens vault and iris volume, which decreased at PDH1 and PDH4 from baseline. Increase in anterior chamber depth was negatively associated with the level of IOP elevation after dilation (P < 0.01).

CONCLUSIONS

Dilation of patients' eyes with PACS and VSC in this cohort appears to have a low risk for IOP spike. This may be associated with relaxation of the ciliary muscle leading to posterior displacement of the lens-iris diaphragm and deepening of the anterior chamber.

Effect of Visibility of the Ciliary Body Processes on Ocular Biometric Parameters in Patients with Primary Angle Closure

PURPOSE

To evaluate the differences in ocular biometric parameters between eyes with primary angle closure (PAC) with and without visible ciliary body processes (CBP) (PAC+CBP and PAC-CBP) and normal open-angle controls.

STUDY DESIGN

Cross-sectional study.

METHODS

Eyes with PAC and normal open-angle controls underwent detailed ocular examinations and gonioscopy to determine the visibility of the CBP. The following ocular biometric parameters were determined using A-scan ultrasound biometry: axial length (AL), anterior chamber depth (ACD), lens thickness (LT), and vitreous length (VL). The lens-axial length factor (LAF) and relative lens position (RLP) were also calculated. Continuous variables were assessed by analysis of variance with Bonferroni correction. Multiple linear regression analysis was performed to adjust for confounding factors. Area under the receiver operating characteristic curves were calculated to determine the diagnostic capability of biometric parameters.

RESULTS

84 PAC+CBP eyes, 57 PAC-CBP eyes, and 32 normal open angle control eyes were evaluated. The means of the ocular biometric values were significantly different among the three groups. AL, ACD, LT, VL, LAF, and RLP were also significantly different among the three groups in the multivariate regression analysis. AL, ACD, and VL were lower in the PAC+CBP group and LT, RLP, and LAF were greater in the PAC+CBP group than in the PAC-CBP and control groups. LAF ≥ 2.4 is the cutting point with the highest sensitivity and specificity to differentiate PAC+CBP from PAC-CBP.

CONCLUSIONS

The ocular biometric parameters in the PAC+CBP group were more strongly associated with a crowded anterior segment than in the other groups. Visibility of CBP in PAC-affected eyes may serve as a surrogate for an anterior segment crowding mechanism and help to select the most appropriate treatment in individual cases.

Volumetric parameters-based differentiation of narrow angle from open angle and classification of angle configurations: an SS-OCT study

BACKGROUND

To evaluate the diagnostic ability of volumetric parameters to differentiate narrow angle from open angle and distinguish different configurations of narrow angle.

METHODS

The current study was composed of two parts. In the first part, with gonioscopy as reference standard, we tested power of each parameter to differentiate narrow angle from open angle. In the second part, we evaluated the efficacy of different parameters to distinguish angle configurations which were subclassified into type 1 (pupillary block) and type 2 (non-pupillary block and multiple mechanisms) based on ultrasound biomicroscopy (UBM) images.

RESULTS

In part 1, the training set was composed of 117 narrow-angle eyes and 60 open-angle eyes, and the validation set included 38 narrow-angle eyes and 37 open-angle eyes. Anterior chamber volume (ACV) outperformed all the other parameters with an area under the curve (AUC) of 0.988. The sensitivity and specificity of the cut-off value 98.1 mm³ in the validation set were 90.0% and 97.1%, respectively. In part 2, training set was composed of 96 eyes of 88 patients with primary angle-closure disease, with 49 diagnosed as type 1 and 47 as type 2 configuration. 32 eyes were used for validation. A model comprised of iris volume (IV), iris thickness (IT) 2000 µm from the scleral spur and angle open distance (AOD) 750 µm from the scleral spur was found to have an AUC of 0.793 (95% CI, 0.695 to 0.870). Sensitivity and specificity of the model were 82.6% and 77.8% respectively in the validation set.

CONCLUSIONS

With ACV, we can detect patients with narrow angle from open angle faster and more easily than AOD and anterior chamber depth. Then, for patients with narrow angle, the combination of IV, IT and AOD750 measured by swept-source optical coherence tomography could further classify configurations of angle closure compared with UBM.

Primary Angle-Closure Glaucoma With Normal Intraocular Pressure at the First Visit: Its Prevalence and Ocular Characteristics

PURPOSE

To investigate the prevalence of normal intraocular pressure (IOP) at first visit among patients with primary angle-closure glaucoma (PACG) and their ocular characteristics.

PATIENTS AND METHODS

We retrospectively reviewed patients with PACG in a referral center. According to untreated IOP, we divided PACG eyes into 2 groups: those with normal IOP and those with high IOP (>21 mm Hg) at the first visit.

RESULTS

One hundred sixty eyes of 160 Korean PACG patients were included. Sixty percent (97/160) of the patients had normal IOP at their first visit. The PACG patients with initially normal IOP had significantly longer axial length (mean±SD, 22.99±0.76 vs. 22.74±0.61) and deeper "true" anterior chamber depth (ACD) (2.09±0.27 vs. 1.82±0.33) than those with initially high IOP (both P<0.05). Multiple logistic regression revealed that deeper "true" ACD (per 0.1 mm; odds ratio, 1.38) and more hyperopic refractive errors (odds ratio, 1.48) were independent predictors of initially normal IOP in PACG eyes (P<0.05). The prevalence of disc hemorrhage was higher in PACG patients with initially normal IOP than in those with initially high IOP (29.9% vs. 14.3%, P=0.029).

CONCLUSIONS

Sixty percent of patients with PACG had normal IOP at their first visit. This suggests that without gonioscopy clinicians may misdiagnose PACG as normal tension glaucoma. ACD measurement can aid the diagnosis of PACG because even PACG eyes with initially normal IOP have shallow ACD.

Limbus-insertion distance of superior rectus in primary angle closure glaucoma: an anterior segment OCT study

OBJECTIVE

To compare the distance from the corneoscleral limbus to the insertion site of the superior rectus of primary angle-closure glaucoma (PACG) patients with normal controls and to identify potential characteristics associated with limbus-insertion distance.

DESIGN

Cross-sectional study.

PARTICIPANTS

A total of 92 subjects (eyes) were enrolled in the study: 35 were nonglaucoma controls and 57 were PACG patients.

METHODS

The limbus-insertion distance of the superior rectus was measured by anterior segment optical coherence tomography (AS-OCT) and intraoperative surgical caliper. The anterior chamber parameters were also measured using AS-OCT to identify potential characteristics associated with limbus-insertion distance.

RESULTS

The limbus-insertion distance of the superior rectus was 0.40 ± 0.08 mm shorter in the PACG group than in the normal control group (p < 0.001). Anterior segment parameter values, including anterior chamber depth (ACD), anterior chamber width (ACW), anterior chamber area (ACA), and anterior chamber volume (ACV), were smaller in the PACG group than in the normal control group, but the lens vault was larger (all p < 0.001). A shorter limbus-insertion distance of the superior rectus was significantly associated with shorter axial length and "crowded" angle (smaller ACD, ACW, ACA, and ACV) (all p < 0.05).

CONCLUSIONS

This is the first study to demonstrate that the limbus-insertion distance of the superior rectus was shorter in PACG eyes than in normal eyes. The shorter limbus-insertion distance may be another anatomic characteristic of PACG eyes.

Primary Angle Closure and Sequence Variants within MicroRNA Binding Sites of Genes Involved in Eye Development

Purpose

The formation of primary angle closure (PAC) and primary angle closure glaucoma (PACG) is regulated by a tissue remodeling pathway that plays a critical role in eye development. MicroRNAs (miRNAs) are powerful gene expression regulators and may exert their effects on tissue remodeling genes. This study investigated the associations between gene variants (single-nucleotide polymorphism, SNP) in miRNA binding sites in the 3’-UTR region of genes involved in eye development and PAC.

Methods

The sample consisted of 232 PAC subjects and 306 controls obtained from a population-based cohort in the Funing District of Jiangsu, China. The markers include 9 SNPs in the COL11A1, PCMTD1, ZNRF3, MTHFR, and ALPPL2 genes respectively. SNP genotyping was performed with a TaqMan-MGB probe using an RT-PCR system.

Results

Of the 9 SNPs studied, the frequency of the minor A allele of COL11A1 rs1031820 was higher in the PAC group than in the control group in allele analysis (p = 0.047). The genotype analysis indicated that MTHFR rs1537514 is marginally associated with PAC (p = 0.014). The CC genotype of rs1537514 was present solely in the PAC group. However, the differences lost significance after Bonferroni correction.

Conclusion

Our study reveals a possible association of COL11A1 and MTHFR with PAC in the Han Chinese population. These results will contribute to an improved understanding of the genetic basis of PACG.

Angle Closure Scoring System (ACSS)-A Scoring System for Stratification of Angle Closure Disease

Purpose

To evaluate the angle closure scoring system (ACSS) for stratifying primary angle course disease.

Methods

This observational cross sectional institutional study included patients with primary open angle glaucoma suspects (n = 21) and primary angle closure disease (primary angle closure, PAC, n = 63 and primary angle course glaucoma, PACG, n = 58 (defined by International society of Geographical and Epidemiological Ophthalmology, ISGEO). Two independent examiners blinded to clinical details, graded good quality pre-laser goniophotographs of the patients incorporating quadrants of peripheral anterior synechieae (PAS), non-visibility of posterior trabecular meshwork (PTM) and blotchy pigments (ranging from 1–4 quadrants), iris configuration, angle recess (sum of above depicting ACSS_g) and lens thickness/axial length ratio (LT/AL), cup disc ratio and baseline intraocular pressure (IOP) to give total score (ACSS_t).

Result

There were significant differences in ACSSg scores within the same ISGEO stage of PAC and PACG between eyes that required nil or >1medicines after laser iridotomy, p<0.001. The ACSSg was associated with need for >1 medicines in both PAC and PACG eyes, p<0.001. An ACSSg score>12 and 14 in PAC (odds ratio = 2.7(95% CI-1.7–5.9) and PACG (Odds ratio = 1.6(95%CI-1.19–2.2) predicted need for single medicines while ACSSg scores >14 and 19 predicted need for ≥2 medicines in PAC and PACG eyes, respectively. The LT/Al ratio, IOP score or cup disc score did not influence the need for medical treatment independently.

Conclusion

The ACSS can be a useful clinical adjunct to the ISGEO system to predict need for medicines and prognosticate each stage more accurately.

Topographic profile of choroid in eyes after acute primary angle-closure

OBJECTIVE

To characterize and compare the topographic profile of choroid in eyes after acute primary angle-closure (APAC) and in normal controls.

DESIGN, SETTING, AND PARTICIPANTS

A prospective observational study was conducted. Forty-four consecutive patients who had experienced unilateral APAC that was resolved by treatment were recruited. Seventy age- and sex-matched normal individuals were recruited as controls.

METHODS

Enhanced depth imaging-optical coherence tomography was used to measure choroidal thickness (CT) in 9 diffuse locations of macular region. The average CT was compared among each location in the APAC and control groups and between the same locations in the 2 groups.

RESULTS

Variants of CT at different macular locations were found in both groups; it was greatest at subfoveal locations and spread thinner around them, to reach a significant decrease (all p ≤ 0.05) 3 mm away in all directions from the fovea except for the superior direction in normal controls (p = 0.472). Among the 4 directions, the superior had the thickest CT in both groups, followed by the temporal, inferior, and nasal directions in both groups, whereas the APAC had a thicker choroid profile at each location (all p < 0.05). Univariate analysis showed that age, sex, anterior chamber depth, axial length, and spherical equivalent were all associated with the subfoveal choroidal thickness (SFCT) (all p < 0.1). Multivariable linear regression analysis showed that the SFCT was significantly thicker in association with an APAC diagnosis, shorter axial length, greater spherical equivalent refractive error, and younger female subjects (all p ≤ 0.05).

CONCLUSIONS

APAC eyes have a thicker choroid than normal eyes in the macular region, and the increase in CT in APAC eyes follows topographic distribution as in normal control eyes.

Association between choroidal thickness and anterior chamber segment in eyes with narrow or open-angle

AIM

To investigate the relationship between choroidal thickness and anterior chamber segment in subjects with eyes with narrow or open-angle.

METHODS

The subfoveal choroidal thickness was measured with enhanced depth-imaging optical coherence tomography and anterior chamber parameters were measured with ultrasound biomicroscopy in one eye of 23 subjects with open-angle eyes and 38 subjects with narrow-angle eyes. The mean age was 59.52±7.04y for narrow-angle subjects and 60.76±7.23y for open-angle subjects (P=0.514). Multivariate linear regression analysis was performed to assess the association between choroidal thickness and narrow-angle parameters.

RESULTS

There were no differences in subfoveal choroidal thickness between open- and narrow-angle subjects (P=0.231). Anterior chamber parameters, including central anterior chamber depth, trabecular iris angle, iris thickness 500 µm from the scleral spur (IT500), and ciliary body thickness at 1 mm and 2 mm from the scleral spur (CBT1, CBT2) showed significant differences between the two groups (P<0.05). Subfoveal choroidal thickness showed negative correlation (β=-0.496, P=0.016) only with anterior chamber depth in the open-angle group and with age (β=-0.442, P=0.003) and IT500 (β=-0.399, P=0.008) in the narrow-angle group. However, subfoveal choroidal thickness was not correlated with trabecular iris angle, anterior chamber depth, ciliary body thickness, or central corneal thickness in the narrow-angle group.

CONCLUSION

Choroidal thickness does not differ in the two groups and has not correlated with anterior chamber parameters in narrow-angle subjects, suggesting a lack of relationship between choroidal thickness and primary angle-closure glaucoma.

Ocular Biometrics of Myopic Eyes With Narrow Angles

PURPOSE

The purpose of this study was to compare the ocular biometrics between myopic patients with and without narrow angles.

METHODS

Patients with a stable myopic refraction (myopia worse than -1.00 D spherical equivalent) were prospectively recruited. Angle status was assessed using gonioscopy and biometric measurements were performed using an anterior segment optical coherence tomography and an IOLMaster.

RESULTS

A total of 29 patients (58 eyes) were enrolled with 13 patients (26 eyes) classified as having narrow angles and 16 patients (32 eyes) classified as having open angles. Baseline demographics of age, sex, and ethnicity did not differ significantly between the 2 groups. The patients with narrow angles were on average older than those with open angles but the difference did not reach statistical significance (P=0.12). The central anterior chamber depth was significantly less in the eyes with narrow angles (P=0.05). However, the average lens thickness, although greater in the eyes with narrow angles, did not reach statistical significance (P=0.10). Refractive error, axial lengths, and iris thicknesses did not differ significantly between the 2 groups (P=0.32, 0.47, 0.15).

CONCLUSIONS

Narrow angles can occur in myopic eyes. Routine gonioscopy is therefore recommended for all patients regardless of refractive error.

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

Purpose

To compare the clinical and anterior segment anatomical features in primary angle closure sub-groups based on configurations of iris root insertion.

Methods

Primary angle closure patients were imaged using anterior segment optical coherence tomography. Anterior chamber depth, iris curvature, iris thickness (IT) at the scleral spur and 500, 750, and 1,500 µm from the scleral spur (IT₀, IT₅₀₀, IT₇₅₀, and IT₁₅₀₀), lens vault, iris area, angle opening distance (AOD₅₀₀), angle recess area (ARA₇₅₀), and trabecular iris space area (TISA₇₅₀) were measured. Iris root insertion was categorized into a non-basal insertion group (NBG) and basal insertion group (BG).

Results

In total, 43 eyes of 39 participants belonged to the NBG and 89 eyes of 53 participants to the BG. The mean age of participants was greater in the NBG than the BG (62.7 ± 5.7 vs. 59.8 ± 7.3 years, p = 0.043), and the baseline intraocular pressure was higher in the BG than the NBG (16.4 ± 4.4 vs. 14.9 ± 3.3 mmHg, p = 0.037). The BG showed a greater IT₀ (0.265 ± 0.04 vs. 0.214 ± 0.03 mm, p < 0.001) and iris area (1.59 ± 0.24 vs. 1.52 ± 0.27 mm², p = 0.045), lower ARA₇₅₀ (0.112 ± 0.08 vs. 0.154 ± 0.08 mm², p = 0.017) and AOD₅₀₀ (0.165 ± 0.07 vs. 0.202 ± 0.08 mm, p = 0.014) compared to the NBG.

Conclusions

The BG had a narrower anterior chamber angle, thicker peripheral iris, and higher pretreatment intraocular pressure.

Laser peripheral iridotomy changes anterior chamber architecture

PURPOSE

The pressure gradient between anterior and posterior chamber in acute angle closure (AAC) and primary angle closure suspects is balanced by a sufficient laser peripheral iridotomy (LPI). The anterior chamber changes induced by LPI in patients with unilateral AAC were examined and compared to healthy eyes to define threshold values, which may help to discriminate between healthy and diseased eyes.

METHODS

Using Scheimpflug photography, anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), and central corneal thickness (CCT) were measured before and after LPI in both eyes of unilateral AAC cases. These measurements were compared to a group of healthy control eyes to determine threshold values for ACD, ACV, and ACA.

RESULTS

The ACD, ACV, and ACA increased significantly in the 25 AAC eyes after LPI. The ACD, ACV, ACA, and CCT values in the AAC eyes obtained before LPI were compared to a control group of 59 healthy eyes with wide open chamber angles. The cutoff values revealed by receiver operating characteristic analysis were 2.1 mm for ACD, 90.5 mm2 for ACV, and 27.25° for ACA.

CONCLUSIONS

Our results confirm the significant changes of the anterior segments architecture induced by LPI in AAC eyes. The found threshold values for ACD, ACV, and ACA may help in daily clinical routine to discriminate between healthy eyes and those in need for a prophylactic LPI.

Effects of Laser Peripheral Iridotomy in Subgroups of Primary Angle Closure Based on Iris Insertion

Purpose. To investigate the effect of laser peripheral iridotomy (LPI) in subgroups of primary angle closure based on iris insertion configuration. Methods. Anterior segment optical coherence tomography (AS-OCT) images were obtained before and two weeks after LPI. Qualitative classification of angle closure eyes according to iris insertion (basal insertion group (BG) and nonbasal insertion group (NBG)) was performed. Anterior chamber depth (ACD), lens vault (LV), iris curvature, iris area, iris thickness (IT₇₅₀), and angle opening distance (AOD₇₅₀) 750 microns from scleral spur were calculated. Uni- and multivariate regression analysis was carried out to evaluate factors associated with AOD₇₅₀ before and after LPI. Results. Ninety-two eyes of 92 subjects were categorized as NBG (39 eyes) or BG (53 eyes). The mean change after LPI was not significantly different between two groups in all parameters. In both groups, AOD₇₅₀ was affected by ACD (p < 0.001, p = 0.044) before LPI. AOD₇₅₀ was affected by LV (p = 0.012) in NBG, but by ACD (p < 0.001) and IT₇₅₀ (p = 0.039) in BG after LPI. Conclusions. The outcomes of LPI are not significantly different between angle closure subgroups with different iris insertions. However, factors affecting AOD₇₅₀ show differences between two subgroups after LPI.

A practical approach to ocular pain for the non-ophthalmologist

Pain involving the eye has numerous etiologies and is a feared challenge of many clinicians. Between a fear of the patient losing vision and a lack of familiarity with the ophthalmic equipment necessary to diagnose the problem, working up eye pain can be a daunting task. While the ophthalmologist can be indispensable in challenging cases of eye pain, this article will help clarify the unique clinical features of each etiology that can help clinicians narrow down the differential and arrive at a diagnosis.

Postiridotomy ultrasound biomicroscopy features in the fellow eye of Chinese patients with acute primary angle-closure and chronic primary angle-closure glaucoma

PURPOSE

To compare the features of postiridotomy ultrasound biomicroscopy (UBM) in Chinese patients with acute primary angle-closure (aPAC) and with chronic primary angle-closure (cPAC) glaucoma.

PATIENTS AND METHODS

Consecutive cases were classified into acute and chronic groups. The acute group included 77 patients with unilateral aPAC. The chronic group included 57 patients with unilateral advanced cPAC glaucoma. In both the groups, the patients' fellow eye underwent a laser iridotomy and was studied. The main outcome measures included qualitative UBM parameters such as a plateau iris, anterior iris insertion, and an anteriorly rotated ciliary process and quantitative UBM parameters such as central anterior chamber depth (ACD), basal iris thickness (IT500), and scleral ciliary process angle (SCPA).

RESULTS

For the qualitative parameters, more eyes in the chronic group had a plateau iris (P=0.046), an anterior iris insertion (P=0.222), and an anteriorly rotated ciliary process (P=0.090) than those in the acute group. For the quantitative parameters, the eyes in the chronic group had a deeper ACD (P<0.001), thicker IT500 (P<0.001), and smaller SCPA (P<0.001) than those in the acute group.

CONCLUSIONS

The UBM features of Chinese patients with cPAC include a more plateaued iris, a thicker basal iris, and a smaller SCPA, whereas patients with aPAC may have a shallower ACD. For Chinese patients, a nonpupillary block component may play a more important role in asymptomatic cPAC than in aPAC.

Anterior and posterior ocular biometry in healthy Chinese subjects: data based on AS-OCT and SS-OCT

Background

To measure the anterior and posterior ocular biometric characteristics concurrently and to determine the relationship between the iris and choroid in healthy Chinese subjects.

Methods

A total of 148 subjects (270 eyes) were enrolled in this cross-section study. The anterior and posterior ocular biometric characteristics were measured simultaneously by anterior segment optical coherence tomography (AS-OCT) and swept-source optical coherence tomography (SS-OCT).

Results

Compared with male eyes, female eyes had narrower anterior biometric parameters that presented with smaller anterior segment parameters [including anterior chamber depth (ACD), width (ACW), area (ACA), and volume (ACV); (all p<0.001)], narrower anterior chamber angle parameters [including angle opening distance (AOD750), trabecular–iris space area (TISA750), and angle recess area (ARA); (all p<0.001)], higher iris curvature (ICURV) (p = 0.003), and larger lens vaults (LV) (p = 0.019). These anterior ocular biometric parameters were correlated with increasing age (p<0.01). Iris thickness (IT750) and iris area (IAREA) were associated with age, ACW, and pupil diameter (all p<0.05), while choroidal thickness (CT) was associated with age, gender, and axial length (all p<0.05). Univariate regression analysis showed that greater CT was significantly associated with smaller IAREA (p = 0.026).

Conclusion

Compared with male eyes, female eyes had narrower anterior biometric parameters that correlated with increasing age, which would be helpful in explaining the higher prevalence of angle closure rates in the female gender and in aging people. Increased CT might be associated with smaller iris area; however, this possibility needs to be investigated in future studies before this conclusion is made.

Enhancing the early differential diagnosis of plateau iris and pupillary block using a-scan ultrasonography

Purpose

To distinguish the frequently misdiagnosed plateau iris eyes from pupillary block group and normal group, we compared the ocular biometrical parameters of them by A-scan ultrasongraphy.

Methods

In total, we retrospectively reviewed general characteristics and ocular findings including ocular biometric measurements of 71 normal, 39 plateau iris, and 83 pupillary block eyes.

Results

The normal controls, plateau iris group and pupillary block group were significantly different in age, but not in gender. The anterior chamber depth tended to decrease and the lens thickness tended to increase from normal to plateau iris to pupillary block eyes. Compared to those of plateau iris group, the pupillary block group had significantly shallower anterior chamber depth (2.90mm vs. 2.33mm; p<0.001), thicker lens (4.77mm vs. 5.11mm; p<0.001), shorter axial length (23.16mm vs. 22.63mm; p<0.001), smaller relative lens position (2.28 vs. 2.16; p<0.001) and larger lens/axial length factor (2.06 vs. 2.26; p<0.001). However, when comparing plateau iris and normal eyes, only axial length and lens/axial length factor were significantly different (23.16 vs. 23.54; p<0.05 and 2.06 vs. 1.96; p<0.05).

Conclusions

Measured by A-scan ultrasonography, the ocular biometrics of plateau iris were significantly different from those of pupillary block eyes. However, our A-scan ultrasongraphy generally found no significant biometric differences between plateau iris and normal eyes. These findings suggest that while A-scan ultrasonography might be used as a practical tool for differentiating plateau iris and papillary block eyes, a more meticulous gonioscopy and other assessments may be necessary to distinguish plateau iris from normal eyes.

Determinants of anterior chamber angle narrowing after mydriasis in the patients with cataract

PURPOSE

To identify the determinants of anterior chamber angle narrowing after mydriasis by quantitative assessment of the anterior chamber components using anterior segment optical coherence tomography (AS-OCT).

METHODS

In this intervention study, anterior chamber angle analysis was performed using AS-OCT in patients with cataract before pharmacological pupillary dilation and 30 min afterwards. Angle narrowing was quantified by the change of angle opening distance 500 after mydriasis (ΔAOD500). Multivariate linear regression and stepwise selection regression were used to identify which parameters in AS-OCT significantly determined ΔAOD500.

RESULTS

One hundred and two Japanese patients (age, mean ± standard deviation, 71.9 ± 11.2 years) were enrolled. Multivariate analysis indicated that smaller ΔAOD500 were significantly associated with larger lens vault (LV; P < 0.001), larger iris area (IA; P = 0.003), and posterior corneal arch distance (PCAL; P = 0.01). Stepwise linear regression analysis revealed that smaller ΔAOD500 was independently associated with larger LV (partial R (2) = 0.232, P < 0.001), larger IA (partial R (2) = 0.080, P = 0.001), and smaller PCAL (partial R (2) = 0.066, P = 0.002) before mydriasis. These three factors explained 37.7 % of the decrease in ΔAOD500.

CONCLUSION

Larger LV, larger IA, and smaller PCAL contribute considerably to anterior chamber angle narrowing after mydriasis in patients with cataract.