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

Abstract

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.

Ocular Manifestations of Acute Secondary Angle Closure Associated With Lens Subluxation

“…The common manifestations of lens subluxation are progressive refractive modifications (myopia and astigmatism) with decreased vision (amblyopia in children), glaucoma (through different mechanisms), and in some cases retinal detachment (13). The ocular signs of lens subluxation include abnormal ACD (shallower ACD, deeper ACD, uneven ACD among the quadrants, and great difference in ACD in the center of each eye), iridodonesis, phacodonesis, anterior displacement of the iris lens diaphragm, decentration of the nucleus, visible lens equator margin through the dilated pupil, and vitreous in the anterior chamber (8,10). With the development of technology, multiple anterior segment imaging instruments can be used to objectively and accurately visualize and evaluate anterior segment parameters, such as the Scheimpflug imaging-based system (Pentacam), anterior segment optical coherence tomography (AS-OCT), and UBM (14).…”

“…UBM is a high-frequency, high-resolution imaging technique that offers cross-sectional images of the anterior segment to a depth of 5 mm (15). It can image and evaluate the morphological structure of the anterior segment of the eye, even the structure beyond the iris covering, such as the ciliary body, zonule, and peripheral and posterior lens without mydriasis (10). Moreover, UBM demonstrates high sensitivity, specificity, and accuracy for the detection of lens dislocation (15,16).…”

“…This condition can sometimes induce acute secondary angle closure (ASAC) that presents with non-specific signs and symptoms, similar to acute primary angle closure (APAC), such as blurred vision, elevated intraocular pressure (IOP), shallow anterior chamber, severe ocular pain, headache, nausea, and vomiting. According to earlier studies, about 4.1-21% of ASAC cases, associated with lens subluxation (ASAC-LS) were misdiagnosed as APAC (8)(9)(10)(11). Due to a wide range of causes for angle closure, the management and operation protocols for these patients can be vastly different.…”

Exploring the Occurrence Mechanisms of Acute Primary Angle Closure by Comparative Analysis of Ultrasound Biomicroscopic Data of the Attack and Fellow Eyes

“…The clinical study was purely academic with no involvement of commercial activities. [11] (1) No major underlying disease requiring medical or surgical intervention (excluding patients with hypertension, diabetes, dialysis for renal failure, immune diseases requiring long-term oral hormone treatment, and long-term chemotherapy after surgery for a malignant tumor)…”

“…Finally, this study belonged to the second part of the overall study. The first part was the comparative analysis of the qualitative parameters of UBM, and the third part was the discussion of the mechanism of acute angle closure secondary to lens subluxation [11].…”