Role of lens vault in subtypes of angle closure in Iranian subjects

Quantitative analysis of dynamic iris changes in primary angle-closure disease with long axial lengths: the Handan Eye Study

OBJECTIVE

To investigate dynamic iris changes in patients with primary angle-closure disease (PACD) with long axial length (AL) compared to those with short and medium AL.

METHODS

This observational cross-sectional study enrolled participants aged 35 years or older from the Handan Eye Study follow-up examination who were diagnosed with PACD and underwent Visante anterior segment optical coherence tomography (ASOCT) imaging under light and dark conditions. The right eye of each participant was included in the analysis. AL was categorized as short (<22.0 mm), medium (≥22.0 to ≤23.5 mm), or long (>23.5 mm). Anterior segment parameters, including iris dynamic changes, were compared among the three groups with different ALs.

RESULTS

Data from 448 patients with PACD were analyzed. We found that 10.9% of included eyes had a long AL with a flatter cornea; larger central anterior chamber depth, angle opening distance, anterior chamber width, anterior chamber area, and volume; and smaller lens thickness and lens vault (LV) (P < 0.05) than those with short AL. No significant difference existed between the three groups in iris thickness, iris cross-sectional area (IA), iris curvature, or pupil diameter (PD) change between light and dark (P > 0.05). The significant associated factors for IA changes were area recess area (ARA) in the dark, LV in the dark, and PD change from light to dark (P < 0.05).

CONCLUSIONS

Dynamic and static iris parameters were consistent across patients with PACD with short, medium, or long AL and may contribute to the pathogenesis of angle closure in atypical PACD.

Contemporary Approach to Narrow Angles

Glaucoma is the leading cause of irreversible blindness worldwide. Among all glaucoma types, primary angle closure glaucoma (PACG) affects approximately 23 million people worldwide, and is responsible for 50% of glaucoma-related blindness, highlighting the devastating consequences of this disease. The main mechanism of PACG is relative pupillary block. High-risk populations are female gender, Asian ethnicity, high hyperopia, short axial length, and a thick/anteriorly positioned lens. This review discusses the clinical diagnosis, classification, and management of patients with a narrow angle with and without intraocular pressure (IOP) elevation and glaucomatous optic nerve damage, including laser peripheral iridotomy (LPI), endocycloplasty (ECPL), lens extraction, and goniosynechialysis.

Imaging analysis of the biological parameters of the lens in patients with cortical age-related cataracts using ultrasound biomicroscopy

BACKGROUND

The spatial position of the lens in patients with cortical age-related cataract (CARC) is unclear. We investigated a basis for the assessment of visual quality after cataract surgery by analysing the ultrasound biomicroscopic characteristics of the biological parameters of the lens in patients with CARC.

METHODS

In this retrospective study, 119 patients (50 males and 69 females, totalling 238 eyes) with CARC who underwent simple cataract surgery were selected. The lens thickness (LT), axial length (AL), anterior chamber depth (ACD), lens vault (LV), trabecular-iris angle (TIA), iris-lens angle (ILA), iris-lens contact distance (ILCD) were measured by A-scan ultrasound and ultrasound biomicroscopy. The corresponding lens position (LP) and relative lens position (RLP) were calculated.

RESULTS

LP was greater in men than in women (P < 0.05), LV was smaller in men than in women (P = 0.002), ILA and ILCD were not statistically significant (P = 0.072 and P = 0.854, respectively). There were significant differences in TIA, ILA, and ILCD in the four quadrants (all P < 0.05), with a trend in the distribution of TIA: superior < inferior < nasal < temporal, ILA: nasal < inferior < temporal < superior, and ILCD: superior < temporal < inferior < nasal.

CONCLUSIONS

The lens protrudes more obviously in females than in males and the lens tilts to a certain extent with the increase of age and tends to be more upward and temporal in the supine position. Therefore, trends in lens-related parameters in patients with CARC should be taken seriously.

Ocular morphologic traits in the American Cocker Spaniel may confer primary angle closure glaucoma susceptibility

Acute primary angle closure glaucoma is a potentially blinding ophthalmic emergency requiring prompt treatment to lower the elevated intraocular pressure in humans and dogs. The PACG in most of canine breeds is epidemiologically similar to humans with older and female patients overrepresented with the condition. The American Cocker Spaniel (ACS) is among the most common breeds observed with PACG development in dogs. This study initially sought to identify genetic risk factors to explain the high prevalence of PACG in ACSs by using a case-control breed-matched genome-wide association study. However, the GWAS failed to identify candidate loci associated with PACG in this breed. This study then assessed intrinsic ocular morphologic traits that may relate to PACG susceptibility in this breed. Normal ACSs without glaucoma have a crowded anterior ocular segment and narrow iridocorneal angle and ciliary cleft, which is consistent with anatomical risk factors identified in humans. The ACSs showed unique features consisting of posterior bowing of iris and longer iridolenticular contact, which mirrors reverse pupillary block and pigment dispersion syndrome in humans. The ACS could hold potential to serve as an animal model of naturally occurring PACG in humans.

Relationship Between Optical Coherence Tomography and Anterior Chamber Depth After Pupillary Dilation in Primary Angle Closure Suspects

PRCIS

Anterior chamber depth (ACD) change after pupillary dilation is correlated with lens vault (LV) and anterior chamber width (ACW), as observed by swept-source optical coherence tomography (SS-OCT) at both horizontal and vertical scans in patients with primary angle closure suspect and cataract.

PURPOSE

The purpose of this study is to evaluate the association between ACD and other anterior chamber parameters after pharmacological dilation in patients with primary angle closure suspect and cataract.

PATIENTS AND METHODS

SS-OCT was performed for 78 patients at baseline and 1 hour after pharmacological dilation. Measurements were taken at 8 evenly spaced axes at 250, 500, and 750 μm from the scleral spur. Pearson correlation coefficient (ρ) was used to evaluate the relationship between averaged ACD change and other SS-OCT parameters. Multivariable regression analyses were performed to determine the parameters that predict ACD change.

RESULTS

Across all 14 dimension and angle parameters, 12 parameters at the 270-degree axis and 10 parameters at the 0-degree axis yielded significant correlations with ACD change (ρ=0.24-0.55, P <0.05). Angle parameters were most significantly correlated to ACD change 750 µm from the scleral spur. The prediction model for ACD change after pharmacological dilation at 0 degree included decreased LV, wider ACW, and increased trabecular iris space area (all P ≤0.001). The prediction model for ACD change at 270 degrees included: decreased LV, wider ACW, larger change in anterior chamber volume, larger baseline anterior chamber volume, and smaller baseline angle opening distance (all P ≤0.03).

CONCLUSIONS

LV and ACW, as measured in both vertical and horizontal scans, were found to be determinants of the ACD change after pharmacological pupillary dilation. Examination of these parameters may help identify patients at higher risk of developing angle-closure disease.

Classifications of Qualitative Characteristics on Angle Configurations via Ultrasound Biomicroscopy in Acute Primary Angle Closure

Purpose

To study the classifications of qualitative characteristics on the angle configurations in the acute primary angle closure (APAC) and fellow eyes by ultrasound biomicroscopy (UBM).

Methods

A total of 131 patients (262 eyes) were researched retrospectively. The qualitative parameters from UBM images were classified into iris form (IF), ciliary body configuration (CBC), basal iris thickness (BIT), iris convexity (IC), iris insert (II), iris angulation (IA), ciliary body size (CBS) and ciliary body position (CBP). Comparative analyses between the APAC (case group) and fellow (control group) eyes were performed.

Results

There were significant differences in IF, CBC, IC, II, CBS, CBP between the case group and control group in all quadrants (P<0.001). The IA of the case group and control group presented significant difference in all quadrants (P=0.001). However, there was not a significant difference in BIT between the case group and control group in all quadrants (P=0.495). The case group had fewer parallelogram-like and mushroom-like and more cone-like and hook-like CBCs than the control group (P<0.001).

Conclusion

Multiple ciliary body configurations can influence the stability of the lens and the anatomic configuration of the anterior chamber angle indirectly. New qualitative classification system of UBM may be more intuitionistic and refined to reflect the angle configurations to help clinical practice.

Correlation of pattern of visual field loss by perimetry and anterior chamber angle parameters by anterior segment optical coherence tomography in primary angle-closure glaucoma

Purpose

To correlate and analyze the pattern of the visual field (VF) defects by perimetry and anterior chamber angle parameters by AS-OCT in primary angle-closure glaucoma (PACG) across varied severity levels on presentation to a tertiary eye care center.

Methods

This was a cross-sectional study, which included 323 eyes of clinically diagnosed cases of PACG. Glaucoma severity was categorized according to mean deviation (MD) as mild (-6.00 dB or more), moderate (-6.01 to -12.00 dB), and severe (-12.01 to -30.00 dB). AS-OCT measured the nasal (N) and temporal (T) angle opening distance at 500 μm (AOD 500) and 750 μm (AOD 750), anterior chamber angle (ACA), lens vault (LV), and anterior chamber width (ACW). The VF severity was then correlated with the AS-OCT parameters using statistical analysis.

Results

The mean age ± standard deviation (SD) of the patients included in the study was 56.03 ± 8.6 years, with a 1:1.2 gender ratio. The number of eyes with mild, moderate, and severe VFs were 140 (43.3%), 88 (27.24%), and 95 (29.41%), respectively. There was no statistically significant correlation in the mean anterior chamber angle parameters (AOD 500, AOD 750, ACA 500, ACA 750, LV, ACW, and axial length (AL)) among the groups. However, the correlation between AOD 500 and LV thickness was found to be significant (P = 0.0000) with a negative Spearman's rank correlation coefficient (r = -0.3329).

Conclusion

The ACA parameters obtained by AS-OCT along the horizontal axis after elimination of pupillary block by laser peripheral iridotomy do not correlate and cannot be used to assess the disease severity of PACG.

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.

Analyzing Anatomical Factors Contributing to Angle Closure Based on Anterior Segment Optical Coherence Tomography Imaging

PURPOSE

To analyze anatomical factors contributing to angle closure based on anterior segment optical coherence tomography (AS-OCT) imaging.

METHODS

A total of 238 patients with angle closure and 1122 normal controls were consecutively recruited for this study. Participants' eyes were imaged using AS-OCT under the same darkened ambient light conditions. The following parameters were analyzed: central anterior chamber depth (ACD); anterior chamber area (ACA); anterior chamber volume (ACV), anterior chamber width (ACW); corneal diameter (CD); posterior cornea curvature (PCC); anterior cornea curvature (ACC); maximum iris thickness (ITM); iris thickness at 750 um (IT750) and 2000 um (IT2000) from the scleral spur; iris curvature (IC); iris area (IA); lens vault (LV); angle opening distance (AOD); trabecular iris space area at 500 um (TISA500) and 750 um (TISA750) from the scleral spur; angle recess area (ARA). Lasso regression models were used to detect the collinearity of parameters. The multivariable logistic regression was performed to determine the independent association between angle closure and those parameters included in Lasso regression model. Also Factor analysis was performed to extract a few underlying factors (components) from these parameters.

RESULTS

Lasso regression showed that ACD, ACV, PCC, IT750, IT2000 and LV were screened in the model. The multivariable logistic regression indicated that ACV, PCC, IT750 and LV were significantly associated with angle closure. Factor analyses revealed that 4 factors, each with its closely associated clusters of variables, produced the best results: ACA, ACV and ACD (Factor 1); LV, tIC and nIC, (Factor 2); ACW, CD and PCC (Factor 3); and tITM, tIT2000, tIT750, nIT2000 and nIT750 (Factor 4).

CONCLUSIONS

Four separate mechanisms were showed to be involved in the pathogenesis of angle closure, from anterior chamber dimensions, lens, iris and cornea respectively. The parameters ACV, PCC, IT750, and LV are more predominant in determining angle closure.

Trends in the characteristics of acute primary angle closure in Korea over the past 10-years

Purpose

To investigate the changes in the demographic, clinical, and biometric characteristics of APAC patients in South Korea during the last decade.

Methods

Medical records of patients with APAC who visit the emergency department or the glaucoma clinic of Chonnam National University Hospital, a tertiary referral center in Gwangju, South Korea in 2007 and 2017 were analyzed. Demographics, clinical characteristics, and treatment modality were compared between the APAC patients in 2007 and 2017.

Results

The number of patients with APAC increased from 54 in 2007 to 68 in 2017. Female patients in their 60s were most common in both groups and there was no significant difference in IOP, cataract grade, gonioscopic grading, PAS, or optic nerve damage between the two groups at baseline visit (all P > 0.05). However, APAC eyes in 2017 had a shallower ACD (1.74 ± 0.28 mm vs 1.87 ± 0.35 mm; P = 0.024) and greater LV (1.05 ± 0.26 mm vs 0.93 ± 0.19 mm; P = 0.001) than those of APAC eyes in 2007. During one year follow-up, 25 patients (51.02%) received LPI only, and 18 patients (36.73%) required LE, and 6 patients (12.24%) required phacotrabeculectomy or sequential LE and trabeculectomy. However, in 2017, LPI alone was sufficient in 23 patients (38.33%), 29 patients (48.33%) required further LE, and 8 patients (13.33%) required phacotrabeculectomy or sequential LE and trabeculectomy for the treatment of APAC (P = 0.015).

Conclusions

Compared to older cases of APAC, recent cases received LE more frequently, which suggests an increasing trend of LE as a treatment option for APAC. In addition, recent cases had a greater LV and shallower ACD than older cases and these biometric differences may be one of the reasons for increasing rate of LE in this study.

Characteristic Manifestations regarding Ultrasound Biomicroscopy Morphological Data in the Diagnosis of Acute Angle Closure Secondary to Lens Subluxation

Purpose

To investigate the mechanisms underlying the occurrence of acute angle closure (AAC) and to further explore the sensitive indicators for clinical diagnosis of acute angle closure secondary to lens subluxation (AACSLS) through qualitative and quantitative analysis of ultrasound biomicroscopy (UBM) imaging features of eyes with AAC to provide a theoretical basis for the selection of treatment schemes.

Methods

A retrospective analysis was conducted from 2013 to 2018 on 160 eyes (160 patients) with uniocular acute angle closure crisis (AACC) complicated by cataract. The case group consisted of 29 eyes (29 patients) with lens subluxation and the control group consisted of 131 eyes (131 patients) without lens subluxation. Before the operation, computer optometry, best corrected visual acuity, intraocular pressure, slit lamp, gonioscopy, preset lens, A-mode ultrasonography, and UBM were performed. All the enrolled subjects underwent cataract surgery with or without other operations. The pupil was fully dilated, and the position of the lens was recorded before the operation. The zonular rupture and lens subluxation were further confirmed during operation. SPSS version 20.0 was used to analyze UBM imaging data from the lens subluxation group and non-lens subluxation group.

Results

The iris span (IS) value in the whole quadrant of the lens subluxation group was significantly higher than that of the non-lens subluxation group (P=0.033, 95%CI 0.01 to 0.31). The iris lens angle (ILA) in the lens subluxation group was significantly lower than that in the non-lens subluxation group in the upper, lower, nasal, temporal, and whole quadrants (P<0.001, 95%CI -8.79 to -2.78; P=0.001, 95%CI -8.36 to -2.27; P<0.001, 95%CI -9.85 to -4.98; P=0.015, 95%CI -6.67 to -0.72; P<0.001, 95%CI -8.74 to -5.83, respectively). However, the ILA of the maximum difference among the four quadrants in the lens subluxation group was significantly higher than that in the non-lens subluxation group (P<0.001, 95%CI 4.74 to 9.86). The ILA and iris lens contact distance (ILCD) showed significant negative correlations in both the lens subluxation group and non-lens subluxation group (Y=20.984-7.251X, R=0.520, and P<0.001; Y=19.923-3.491X, R=0.256, and P<0.001, respectively). The risk ratio of lens subluxation in exposed eyes with ILA=0 in one quadrant at least was significantly higher than that in nonexposed eyes without ILA=0 in all quadrants (X²=87.859, P<0.001, and odds ratio (OR)=79.200, 95% CI 23.063 to 271.983). The risk ratio of zonular rupture in exposed quadrants with ILA=0 was significantly lower than that in nonexposed eyes without ILA=0 (X²=33.884, P<0.001, OR=0.122, and 95% CI 0.053 to 0.278). The risk ratio of zonular rupture in exposed quadrants with nonforward convexity of iris was significantly lower than that in nonexposed quadrants with forward convexity of iris (X²=6.413, P=0.011, and OR=0.381; 95% CI 0.176 to 0.825).

Conclusions

ILA=0 and nonforward convexity of iris as UBM sensitive and characteristic indicators for screening lens subluxation and zonular rupture can provide new ideas and hints for clinical diagnosis of acute angle closure secondary to lens subluxation.

Association between serotonin-norepinephrine reuptake inhibitors and acute angle closure: What is known?

Serotonin-norepinephrine reuptake inhibitors are widely used antidepressants with a relatively safe profile. One of the complications associated with this group of drugs is acute angle closure. The mechanisms linking serotonin-norepinephrine reuptake inhibitors and acute angle closure are complex and may be interlinked with the effects of the drug on the inhibition of serotonin and noradrenaline reuptake, as well as pseudo-anticholinergic effects, dopaminergic effects, and idiosyncratic reactions with the drug molecule in the eye. Individual characteristics, such as polymorphisms of the gene encoding the 2D6 subunit of cytochrome P450, may affect the metabolism of the serotonin-norepinephrine reuptake inhibitor, whereas the combination with other drugs may lead to an increased risk of iridocorneal angle closure and may further exacerbate other mechanisms. Improved knowledge of the mechanisms linking serotonin-norepinephrine reuptake inhibitors and acute angle closure and of the risk factors predisposing to patients to acute angle closure will reduce the number of patients affected by this dangerous complication.

Classification of primary angle closure spectrum with hierarchical cluster analysis

PURPOSE

To classify subjects with primary angle closure into clusters based on features from anterior segment optical coherence tomography (ASOCT) imaging and to explore how these clusters correspond to disease subtypes, including primary angle closure suspect (PACS), primary angle closure glaucoma(PACG), acute primary angle closure (APAC) and fellow eyes of APAC and reveal the factors that become more predominant in each subtype of angle closure.

METHOD

A cross-sectional study of 248 eyes of 198 subjects(88 PACS eyes, 53 PACG eyes, 54 APAC eyes and 53 fellow eyes of APAC) that underwent complete examination including gonioscopy, A-scan biometry, and ASOCT. An agglomerative hierarchical clustering method was used to classify eyes based on ASOCT parameters.

RESULTS

Statistical clustering analysis produced three clusters among which the anterior segment parameters were significantly different. Cluster 1(43 eyes) had the smallest anterior chamber depth(ACD) and area, as well as the greatest lens vault (p<0.001 for all). Cluster 2(113 eyes) had the thickest iris at 2000 microns(p = 0.048), and largest iris area(p<0.001), and the deepest ACD (p<0.001). Cluster 3(92 eyes) was characterized by elements of both clusters 1 and 2 and a higher iris curvature(p<0.001). There was a statistically significant difference in the distribution of clusters among subtypes of angle closure eyes(p<0.001). Although the patterns of clusters were similar in PACS and PACG eyes, with the majority of the eyes classified into cluster 2(55%, and 62%, respectively), the highest proportion of APAC and fellow eyes were assigned to clusters 1(44%) and 3 (51%), respectively.

CONCLUSION

Hierarchical cluster analysis identified three clusters with different features. Predominant anatomical components are different among subtypes of primary angle closure.

Contemporary approach to the diagnosis and management of primary angle-closure disease

The primary angle-closure disease spectrum varies from a narrow angle to advanced glaucoma. A variety of imaging technologies may assist the clinician in determining the pathophysiology and diagnosis of primary angle closure, but gonioscopy remains a mainstay of clinical evaluation. Laser iridotomy effectively eliminates the pupillary block component of angle closure; however, studies show that, in many patients, the iridocorneal angle remains narrow from underlying anatomic issues, and increasing lens size often leads to further narrowing over time. Recent studies have further characterized the role of the lens in angle-closure disease, and cataract or clear lens extraction is increasingly used earlier in its management. As a first surgical step in angle-closure glaucoma, lens extraction alone often effectively controls the pressure with less risk of complications than concurrent or stand-alone glaucoma surgery, but may not be sufficient in more advanced or severe disease. We provide a comprehensive review on the primary angle-closure disease nomenclature, imaging, and current laser and surgical management.

Differences between fellow eyes of acute and chronic primary angle closure (glaucoma): An ultrasound biomicroscopy quantitative study

PURPOSE

To compare various biometric parameters between fellow eyes of acute primary angle closure (glaucoma) [APAC(G)] and fellow eyes of chronic primary angle closure (glaucoma) [CPAC(G)].

METHODS

Ultrasound biomicroscopy examinations were performed on 47 patients with unilateral APAC(G) and 41 patients with asymmetric CPAC(G) before laser peripheral iridotomy and pilocarpine treatment. Anterior chamber depth and width (ACD and ACW), lens vault (LV), iris curvature (IC), iris root distance (IRD), trabecular-ciliary process distance (TCPD), iris-ciliary process distance (ICPD), trabecular-ciliary angle (TCA), and other biometric parameters were compared between fellow eyes of APAC(G) and fellow eyes of CAPC(G).

RESULTS

Compared with fellow eyes of CPAC(G), fellow eyes of APAC(G) had smaller ACD (P < 0.001), ACW (P = 0.007), TCPD (P = 0.016), ICPD (P = 0.008), and TCA (P = 0.006), as well as larger LV (P = 0.002), IC (P = 0.012), and IRD (P = 0.003). On multivariate logistic regression analyses, a 0.1 mm decrease in ACD (odds ratio [OR]: 0.705, 95%CI: 0.564-0.880, P = 0.002), ICPD (OR: 0.557, 95%CI: 0.335-0.925, P = 0.024), and a 0.1 mm increase in IRD (OR: 2.707, 95%CI: 1.025-7.149, P = 0.045), was significantly associated with occurrence of acute angle closures.

CONCLUSIONS

Fellow eyes of APAC(G) had smaller anterior segment dimensions, higher LV, more posterior iris insertion, greater IC, and more anteriorly rotated ciliary body compared with fellow eyes of CPAC(G). ACD, ICPD, and IRD were the three most important parameters that distinguish eyes predisposed to APAC(G) or CPAC(G).

Anterior Segment Dimensions Following Laser Iridotomy in Acute Primary Angle Closure and Fellow Eyes

PURPOSE

To compare the change in anterior segment morphology after laser peripheral iridotomy (LPI) in acute primary angle closure (APAC) and their fellow eyes.

DESIGN

Prospective, fellow eye-matched case series.

METHODS

In this study 42 individuals with unilateral episode of APAC were enrolled and the anterior segment optical coherence tomography (ASOCT) images were obtained in both eyes at baseline and at 6 weeks after LPI. A linear mixed-effects model was used to compare changes in anterior chamber and angle variables with consideration of laterality as the random effect and pupil diameter as the fixed effect.

RESULTS

APAC eyes had smaller angle parameters (P = .013 for all), less central anterior chamber depth (cACD) (P < .001), and lower anterior chamber area (ACA) (P < .001), as well as greater lens vault (LV) (P = .007), compared with fellow eyes. LPI resulted in angle widening with a significant increase in opening distance (P < .01 for all) in both APAC and fellow eyes. cACD (P = .003) and ACA (P < .001) increased and LV (P = .002) decreased in APAC eyes. However, there was no significant change in cACD (P = .190) and LV (P = .430) in fellow eyes. In both APAC eyes and fellow eyes, iris curvature decreased after LPI (P < .001). The changes in angle parameters, ACA, and iris curvature were not significantly different between the 2 groups.

CONCLUSION

In APAC eyes and their fellow eyes, LPI resulted in significant anterior chamber angle widening and increased anterior chamber area. In APAC eyes, the iris flattened, cACD deepened, and the lens shifted posteriorly after resolution of the attack. However, in fellow eyes, the increase in ACA was mainly owing to decreased iris curvature.

Evaluation of anterior chamber parameters with spectral-domain optical coherence tomography

PURPOSE

To evaluate several anterior chamber parameters in healthy young adults using spectral-domain optical coherence tomography and to describe the repeatability and reproducibility of this method.

STUDY DESIGN

Prospective clinical study.

METHODS

Fifty-two eyes of 52 healthy volunteers were enrolled. Manual measurements of the anterior chamber angle (ACA₅₀₀ and ACA₇₅₀), angle opening distance (AOD₅₀₀ and AOD₇₅₀), angle-to-angle distance (ATA), anterior chamber width (ACW), and lens vault (LV) were obtained.

RESULTS

The mean nasal ACA₅₀₀ was 44.87 ± 12.92°; ACA₇₅₀, 43.94 ± 10.41°; AOD₅₀₀, 672.54 ± 270.19 µm; AOD_750, 881.87 ± 290.55 µm. The mean temporal ACA₅₀₀ was 41.46 ± 11.20°; ACA₇₅₀, 41.27 ± 11.31°; AOD₅₀₀, 603.15 ± 232.28 µm; AOD_750, 823.46 ± 308.76 µm. The differences between the corresponding nasal and temporal parameters were statistically significant. The ACW was 11.97 ± 0.42 mm, the ATA was 12.10 ± 0.43 mm, and the LV was 3.71 ± 232.93 µm. The ACA was highly associated with the LV. The intraclass correlation coefficients ranged from 0.984 to 0.999 for the intraobserver repeatability and from 0.966 to 0.998 for the interobserver reproducibility.

CONCLUSIONS

This study assessed anterior chamber parameters in healthy young adults using spectral-domain optical coherence tomography. This technique reveals the spatial relationships of the ocular structures, provides high-resolution images, and results in high degrees of intraobserver and interobserver repeatabilities.

Acute Angle-closure Glaucoma as a First Presentation of Coats' Disease: A Case Report

PURPOSE

The purpose of this study was to report an unusual first manifestation of Coats' disease presenting as an acute angle-closure glaucoma attack in an adult patient.

PATIENTS AND METHODS

A 37-year-old African woman presented to the emergency department with severe headache, ocular pain, and no light perception in the left eye. The left pupil was middilated and nonreactive, and the intraocular pressure (IOP) by applanation tonometry was 47 mm Hg. Slit-lamp examination revealed anterior subcapsular opacification (glaukomflecken), posterior synechiae, and total angle closure with iris bombé. A fundus examination revealed macular exudation, inferior vascular dilation, and tortuosity with peripheral telangiectasia and macroaneurysms, in addition to partial exudative retinal detachment involving the macula. On the basis of these findings, Coats' disease was diagnosed.

RESULTS

The patient was treated with antiglaucoma medications and laser peripheral iridotomy to control the IOP, which had decreased to 21 mm Hg the following day. Diode laser transscleral cyclophotocoagulation was performed to further decrease the IOP. After completing a 360 degree laser, the IOP decreased to 8 mm Hg and then stabilized around 12 mm Hg. The vision remained no light perception; however, the patient felt major symptomatic relief.

CONCLUSIONS

The present case describes acute angle-closure glaucoma as an initial presentation of Coats' disease in adults. Clinicians should be aware that this unique presentation in Coats' disease can occur even without retinal detachment.

Comparison of Anterior Chamber Parameters in Patients With Plateau Iris Configuration and Pupillary Block Using ASOCT

PURPOSE

To quantitatively analyze the anterior chamber parameters in patients with pupillary block (PB) and plateau iris configuration (PIC) using anterior segment optical coherence tomography (ASOCT).

PATIENTS AND METHODS

In this cross-sectional study, nonglaucomatous subjects consecutively recruited and a total of 212 eyes divided into 3 groups of PIC (31 eyes), PB (60 eyes), and open angles (121 eyes) based on gonioscopic and ultrasound biomicroscopy findings. All patients underwent ASOCT imaging and A-scan biometry of both eyes. Anterior chamber depth (ACD), anterior chamber area (ACA), iris thickness (IT), iris curvature, lens vault (LV), anterior vault, and angle parameters including angle opening distance, and trabecular iris space area were measured in qualified images using the Zhongshan Angle Assessment Program, and compared using linear mixed model. The data from 1 eye of each subject were used for final analysis.

RESULTS

Mean age was 64.5±12.1, 64.8±10.5, and 62.3±9.2 years for PB, PIC, and open angle eyes, respectively (P=0.26). There was no significant difference in angle parameters (angle opening distance and trabecular iris space area at 250, 500, and 750 µm from sclera spur), anterior segment parameters (ACD and ACA), iris area, iris curvature, and LV between PB and PIC groups. PIC eyes had greater IT at 750 µm from sclera spur than the PB group (P=0.05). Normal eyes had greater ACD, ACA, and anterior chamber width, and angle parameters and lesser LV and iris curvature than the other 2 groups.

CONCLUSIONS

ASOCT parameters are not significantly different between PB and PIC eyes. PIC eyes may have greater IT at its base.

Qualitative evaluation of anterior segment in angle closure disease using anterior segment optical coherence tomography

PURPOSE

To evaluate different mechanisms of primary angle closure (PAC) and to quantify anterior chamber (AC) parameters in different subtypes of angle closure disease using anterior segment optical coherence tomography (AS-OCT).

METHODS

In this prospective study, 115 eyes of 115 patients with angle closure disease were included and categorized into three groups: 1) fellow eyes of acute angle closure (AAC; 40 eyes); 2) primary angle closure glaucoma (PACG; 39 eyes); and 3) primary angle closure suspect (PACS; 36 eyes). Complete ophthalmic examination including gonioscopy, A-scan biometry, and AS-OCT were performed. Based on the AS-OCT images, 4 mechanisms of PAC including pupillary block, plateau iris configuration, thick peripheral iris roll (PIR), and exaggerated lens vault were evaluated. Angle, AC, and lens parameter variables were also evaluated among the three subtypes.

RESULTS

There was a statistically significant difference in the mechanism of angle closure among the three groups (p = 0.03). While the majority of fellow eyes of AAC and of PACS eyes had pupillary block mechanism (77.5% and 75%, respectively), only 48.7% of PACG eyes had dominant pupillary block mechanism (p = 0.03). The percentage of exaggerated lens vault and plateau iris mechanisms was higher in PACG eyes (25.5% and 15.4%, respectively). Fellow eyes of AAC had the shallowest AC (p = 0.01), greater iris curvature (p = 0.01), and lens vault (p = 0.02) than PACS and PACG eyes. Iris thickness was not significantly different among the three groups (p = 0.45).

CONCLUSION

Using AS-OCT, we found that there was a statistically significant difference in the underlying PAC mechanisms and quantitative AC parameters among the three subtypes of angle closure disease.

Predictors of intraocular pressure change after phacoemulsification in patients with pseudoexfoliation syndrome

AIM

To evaluate anterior chamber biometric factors and intraoperative metrics associated with the intraocular pressure (IOP) reduction after phacoemulsification in non-glaucomatous pseudoexfoliative syndrome (PXS) eyes.

METHOD

Thirty-three patients were enrolled in this prospective interventional study. Images were excluded if they had poor quality, poor perpendicularity or inability to locate sclera spurs. Anterior chamber depth (ACD), anterior chamber area (ACA), iris thickness, iris area, iris curvature, lens vault, angle opening distance (AOD500, AOD750) and trabecular iris space area (TISA500, TISA750) were measured in qualified images using the Zhongshan Angle Assessment Program and compared preoperatively and 3 months postoperatively. Cumulative dissipated energy (CDE), aspiration time and infusion fluid usage during cataract surgery were obtained from the phacoemulsification machine's metrics record. Postoperative IOP change was compared with these anatomical and intraoperative metric parameters.

RESULTS

Mean IOP was 18.1±3.4 mm Hg preoperatively and decreased by 3.3 mm Hg (18%) to 14.8±3.6 mm Hg at 3 months postoperatively (p<0.001). All angle parameters, ACD and ACA increased significantly postoperatively (p<0.001 for all) and iris curvature decreased (p<0.001). In univariate analysis, preoperative IOP (B=-0.668, p=0.002), infusion fluid usage (B=-0.040, p=0.04) and aspiration time (B=-0.045, p=0.003) were negatively associated with IOP decrease after phacoemulsification. Changes in IOP did not demonstrate significant associations with CDE measurements or anterior segment optical coherence tomography measurements, including preoperative angle, iris or anterior segment parameters. In the final multivariate regression model, preoperative IOP (B=-0.668, p=0.002) and infusion fluid usage (B=-0.041, p=0.04) were significantly associated with IOP drop and together can predict 45.1% (p=0.002) of the variability in IOP change.

CONCLUSIONS

Non-glaucomatous patients with PXS experience moderate IOP reduction following phacoemulsification, and this effect is correlated with preoperative IOP, aspiration time and infusion fluid used intraoperatively.

Changes in Anterior Segment Morphology After Laser Peripheral Iridotomy in Acute Primary Angle Closure

PURPOSE

To evaluate the anterior segment biometric changes measured by anterior segment optical coherence tomography (AS-OCT) in acute primary angle closure (APAC) after laser peripheral iridotomy (LPI).

DESIGN

Prospective interventional study.

METHODS

In this clinic-based study, 52 eyes of 52 patients with resolved APAC attack who underwent LPI were enrolled. Subjects underwent complete ophthalmic examination and AS-OCT imaging before and 6 weeks after LPI. Anterior chamber depth (ACD), anterior chamber area (ACA), iris thickness (IT), iris area, iris curvature, lens vault (LV), anterior vault, angle opening distance (AOD500, AOD750), and trabecular iris space area (TISA500, TISA750) were measured in qualified images and compared before and after LPI. A linear mixed-model analysis was performed for potential predictors of change in AOD750. Main outcome measure was change in AOD750 after LPI.

RESULTS

The mean age of participants was 60.7 ± 9.2 years. Mean angle width (Shaffer grade) changed from 0.25 ± 0.34 at baseline to 1.22 ± 0.86 after LPI (P < .001). However, 25 nasal angles (48.0%) and 28 temporal angles (53%) had iridotrabecular contact after LPI. All angle parameters (AOD500, AOD750, TISA500, TISA750; P ≤ .03), ACD (P = .001), and ACA (P < .001) increased significantly after LPI. Iris curvature and LV were reduced (P = .01 for both) after LPI, but there was no significant change in IT and iris area. After multivariate analysis, pre-LPI AOD750 was the only factor associated with change in AOD750 (β = -0.992, P = .02). Exaggerated LV, defined as LV greater than one-third of the anterior vault (sum of LV and ACD), was present in 61.5% of the cases (32 eyes). The extent of change in angle parameters was not significantly different between groups with and without exaggerated LV after LPI.

CONCLUSION

This study confirms that LPI results in a significant increase in the angle width, ACD, and ACA as well as flattening of the iris in APAC eyes. The extent of angle deepening is inversely related to baseline angle width. The lens shifts posteriorly after resolution of attack, especially in those with greater lens vault.

Early phacoemulsification in patients with acute primary angle closure

PURPOSE

To compare long term efficacy of phacoemulsification in the early management of acute primary angle closure (APAC) after aborting an acute attack and performing laser peripheral iridotomy (LPI).

METHODS

In this nonrandomized comparative prospective study, we included 35 subjects presenting with APAC who had responded to medical treatment and LPI with intraocular pressure (IOP) less than 25 mmHg. Twenty patients with visually significant cataract with visual acuity of <20/30 were assigned to the "Phaco/LPI" group and underwent phacoemulsification within 6 weeks of the attack. Fifteen subjects with clear lens were assigned to the "LPI Only" group and were followed clinically. The primary measured outcome was the prevalence of IOP rise after 1 month (treatment failure), defined as 1) if a patient developed IOP rise resulting in IOP >21 mmHg with or without medication, or 2) if a patient required any medication to have IOP ≤21 mmHg after 1 month. Patients were followed for at least one year.

RESULT

IOP, number of medications, gonioscopy grading, and amount of synechiae were not significantly different at baseline between the two groups. Acute attack did not recur in any patient. There was more significant failure in the LPI Only group compared with the Phaco/LPI group (40% vs. 5%; p = 0.02). There was a significant difference in final IOP between the two study groups (13.90 ± 2.17 vs. 17.8 ± 4.16 in the Phaco/LPI and LPI Only groups, respectively; p = 0.001). Patients in the Phaco-LPI group needed less medication than the other group at final follow-up. No serious complications have arisen from the immediate LPI or phacoemulsification.

CONCLUSION

Phacoemulsification is a safe procedure for preventing IOP rise after aborting acute primary angle closure if performed within a few weeks of the attack.