Anterior Chamber Configuration Research Articles

Comparison Between Newly Developed Scanning Peripheral Anterior Chamber Depth Analyzer and Conventional Methods of Evaluating Anterior Chamber Configuration

To compare the newly developed scanning peripheral anterior chamber depth analyzer (SPAC) with the Van Herick technique, the Shaffer grading system, and ultrasound biomicroscopy (UBM), in terms of accuracy of measurement of peripheral anterior chamber depth (ACD). The subjects were well-controlled glaucoma patients who were being treated at the University of Yamanashi Hospital. Ten eyes from each of the 4 groups classified as Shaffer grades 1 to 4 were evaluated by SPAC, the Van Herick technique, and UBM. All measurements were performed independently on the temporal side in a masked fashion. SPAC evaluated ACD consecutively from the pupil center to the limbus at 0.4 mm intervals. UBM measurements were carried out at a depth of 500 mum (angle-opening distance 500) from the scleral spur. A dummy eye was used for evaluating SPAC measurement accuracy. The results of SPAC measurement were well correlated with those of the Van Herick technique and the Shaffer grading system. The SPAC measurement results were also significantly correlated with angle-opening distance 500. The correlation coefficients at distances of 2, 4, 4.8, and 5.6 mm from the pupil center were r=0.68, 0.69, 0.69, and 0.61, respectively, and the P values of all the correlations were less than 0.0001. Study of the dummy eye revealed that SPAC has high accuracy for measuring ACD and that the coefficient variances were less than 1.0% at all measured points. The results of SPAC measurement correlate well with those of the conventional methods.

Intra-observer and inter-observer repeatability of anterior eye segment analysis system (EAS-1000) in anterior chamber configuration.

Anterior chamber configuration can be assessed via optical or ultrasonic techniques. Scheimpflug photography is a non-invasive method measuring the anterior segment. The Anterior Eye Segment analysis system, EAS-1000, utilises the Scheimpflug principle and was found to have good repeatability. Previous repeatability studies, however, have had limitations in their design. The current study investigated the intra-observer and interobserver repeatability of the EAS-1000. Twenty-five healthy young subjects were recruited. The anterior chamber angles in different quadrants were measured by two examiners for interobserver analysis. The first examiner repeated the measurement at another session for intra-observer analysis. The 95% limits of agreement and intra-class correlation coefficient (ICC) were calculated. The anterior chamber depth was also measured and compared with ultrasound biometry. The anterior chamber angle assessment demonstrated good intra-observer (ICC ranging from 0.77 to 0.90 for different quadrants) and interobserver (ICC ranging from 0.68 to 0.81 for different quadrants) repeatability. The 95% intra-observer limits of agreement were within +/-5 degrees. The 95% interobserver limits of agreement were within +/-6 degrees. There was no significant difference between male and female subjects or among angles at different quadrants. The anterior chamber depth was found to be repeatable (ICC > 0.90) with 95% limits of agreement +/-0.1 mm. The anterior chamber depth was shallower than that obtained from ultrasound biometry. The EAS-100 is a non-invasive instrument which is repeatable for measuring the anterior chamber angle and depth. It provides quick results and is good for screening purposes. There is an under-estimation of anterior chamber depth, as previously reported.

Comparison Between the Anterior Chamber Configuration in the Supine Position and That in the Prone Position in Patients with Narrow Angle

To determine whether the anterior chamber configuration of patients with narrow angle is changed in the prone position. The study included 16 eyes of 16 patients whose anterior chamber angle was classified as Shaffer 2 or narrower. The prone position test(PPT) and ultrasound biomicroscopy (UBM) were performed on every subject. In the UBM examination, the following parameters were measured both in the supine position and in the prone position: the angle-opening distance at 250 microns from scleral spur(AOD 250), the angle-opening distance at 500 microns from scleral spur(AOD 500), the trabecular-iris angle(TIA), and the anterior chamber depth at the center of the cornea(anterior chamber depth, ACD). While the intraocular pressure was higher after PPT than before the test, every subject was evaluated as negative for PPT. Mean value of every parameter examined was lower in the prone position than in the supine position(AOD 250: 114 microns, vs. 128 microns, AOD 500: 121 microns vs. 144 microns, TIA: 12.1 degrees vs. 15.5 degrees, ACD: 1966 microns vs. 2002 microns), and the change in ACD was statistically significant (p = 0.013). The anterior chamber configuration of patients with narrow angle is changed in prone position. Such a change can occur in patients classified as negative for PPT.

First day post-operative review following uncomplicated phacoemulsification.

To determine whether the first day review is essential in management of patients following uncomplicated phacoemulsification with intraocular lens implantation. Patients are routinely seen on the day following surgery. This can produce logistical problems in patient attendance that can necessitate an overnight stay. If the first day review were abandoned this would lead to an increased uptake of day case surgery and a reduction in health care costs. A retrospective cohort study was performed on all cases of uncomplicated phacoemulsification with intraocular lens implant surgery over a 6 month period. Slit lamp examination findings on the first post-operative day were reviewed. Visual acuity, corneal clarity, anterior chamber activity, intraocular pressure and configuration of the pupil were recorded. Any cases that failed to meet predetermined criteria underwent full case-note review. The subsequent management of these patients was analysed. Of the 201 cases of uncomplicated surgery, 74 cases (37%) failed to meet the study criteria and underwent review. Of these only 12 (6%) had their management altered as a result of the first day post-operative findings. This was entirely due to raised intraocular pressure. Visual acuity, corneal oedema and activity in the anterior chamber all improved on subsequent follow-up. The first day review of uncomplicated phacoemulsification with lens implant surgery provides the opportunity to treat raised intraocular pressure. A prospective randomised study is needed to identify means to prevent the post-operative intraocular pressure rise before we are able to consider abandoning the first review.

Changes in the Anterior Chamber Configuration After Small-Incision Cataract Surgery With Posterior Chamber Intraocular Lens Implantation

To report quantitative changes in the anterior chamber configuration after small-incision cataract surgery with implantation of a posterior chamber intraocular lens by means of ultrasound biomicroscopy. We examined the anterior chamber configuration of 20 eyes of 20 patients before and 3 months after small-incision cataract surgery (phacoemulsification and aspiration plus foldable intraocular lens implantation through a 3.0- to 4.0-mm self-sealing wound) by means of ultrasound biomicroscopy. The following variables were measured: the anterior chamber depth at the center of the cornea, the angle-opening distance 250 microns from the scleral spur (AOD250), the angle-opening distance 500 microns from the scleral spur (AOD500), and the trabecular-iris angle. The anterior chamber depth at the center of the cornea, AOD250, AOD500, and trabecular-iris angle increased significantly after surgery. The preoperative anterior chamber depth at the center of the cornea and trabecular-iris angle were negatively correlated with the differences between the postoperative and preoperative values (P < .01). The preoperative values of all variables examined were negatively correlated with the ratios of the postoperative value to the preoperative value (P < .002). The present results showed that small-incision cataract surgery significantly deepened the anterior chamber and widened its angle. The more shallow the preoperative anterior chamber was, the greater the postoperative change of the chamber was; and the more narrow the preoperative angle was, the greater the postoperative change of the angle was.

Incidence of Acute Angle-closure Glaucoma After Pharmacologic Mydriasis

To study the incidence of acute angle-closure glaucoma secondary to pupillary dilation and to identify screening methods for detecting angles at risk of occlusion. We studied 5,308 respondents to the Baltimore Eye Survey, a cross-sectional, population-based survey conducted in a multiracial urban community. We measured incidence of acute angle-closure glaucoma after pharmacologic mydriasis and the specificity and sensitivity associated with three screening criteria in identifying those with potentially occludable angles. The screening factors were presence of shallow anterior chamber on penlight examination, history of glaucoma, and blindness. Of the 4,870 subjects whose eyes were dilated on screening examination, none developed acute angle-closure glaucoma. However, 38 patients of the 1,770 who were referred for definitive eye examination were judged to have occludable angles on the basis of gonioscopic methods. Of note, subjects aged 70 years and more were three times more likely to have occludable angles than those aged 40 to 69 years (P < .004) In 14 black subjects with occludable angles, six were detected by history of glaucoma and not by shallow anterior chamber configuration; alternatively, in 24 white subjects, 11 (46%) were detected on the basis of shallow anterior chambers (Fisher's exact test, P = .014). When the three screening factors were considered alone and in combination, the most effective combination for predicting a potentially occludable angle was to use shallow anterior chamber on penlight examination and history of glaucoma. These criteria provide 60.5% sensitivity and 93.3% specificity. If screening is performed accurately and the results are negative, the risk of dilating a potentially occludable angle was less than one in 333 subjects (negative predictive value, 0.997) in this population.

Bilateral angle-closure glaucoma associated with uveal effusion: Presenting sign of HIV infection

A 40-year-old homosexual man presented with acute myopia and bilateral angleclosure glaucoma. Recognition of an anterior chamber configuration of a modestly shallowed central chamber with marked peripheral shallowing clinically suggested uveal effusion. B-scan echography provided definitive, confirmatory evidence of diffuse choroidal thickening with ciliochoroidal effusion. Treatment with aqueous suppressants, cycloplegics, and topical steroids resulted in complete resolution of the angle closure and reversal of induced myopia. The patient, who was systemically well without signs of AIDS or AIDS-related complex, was later tested and found to be serologically-positive for the human immunodeficiency virus.

Vitrectomy for Advanced Stages of Retinopathy of Prematurity

We did a retrospective review of the consecutive vitrectomies for traction retinal detachment associated with retinopathy of prematurity performed at our institution. Fifty-eight eyes were operated on in 46 patients at less than 1 year of age, including 12 eyes with partial retinal detachments and 46 eyes with total retinal detachments. Only patients with at least six months follow-up were considered for success. Twenty-five eyes (43%) were anatomically reattached. Factors associated with good anatomic outcome included greater mean preoperative pupillary dilation, absence of posterior synechiae, deep anterior chamber, partial detachment or open-funnel total detachment configuration, and adequate posterior membrane removal. Of the 25 eyes with attached retinas, 11 had fixing and following visual acuities or better. Three eyes with attached retinas had no light perception and 11 eyes with attached retinas had light perception only. To maximize anatomic and functional results we emphasize the need to operate early, when the retinal funnel is still open.