Changes In Anterior Chamber Research Articles

Biometric Evaluation of Anterior Chamber Changes after Physiologic Pupil Dilation Using Pentacam and Anterior Segment Optical Coherence Tomography

We evaluated changes in anterior chamber (AC) morphology and iris volume induced by physiological mydriasis in fellow eyes of acute angle-closure patients, and age-, sex-, and central AC depth-matched primary angle-closure suspects (PACS). In our study, 21 fellow eyes of patients with acute angle closure; 40 age-, sex-, and central AC depth-matched PACS eyes; and 40 age- and sex-matched normal open-angle eyes were imaged using a Pentacam and anterior segment optical coherence tomography (AS-OCT) under light conditions, and after 5 minutes of darkness using AS-OCT. Iris volume was estimated using AS-OCT and a customized image-processing software. Central AC depth, corneal curvature, axial length, and lens thickness did not differ significantly between the PACS and fellow eyes. When going from light to dark, angle opening distance at 500 μm decreased significantly more in fellow eyes than in PACS (-68% vs. -52%, P < 0.001). When going from light to dark, the mean iris volume increased significantly in the fellow eyes (from 45.34 ± 2.1 to 47.68 ± 3.2 mm(3), P < 0.01), whereas it decreased significantly in most PACS eyes (from 45.01 ± 2.2 to 42.11 ± 2.3 mm(3), P < 0.01), and in all open-angle eyes (from 44.68 ± 1.16 to 41.67 ± 1.20 mm(3), P < 0.01). Based on multivariate analysis, significant predictors of angle narrowing under darkness (relative change in angle-opening distance 500) were fellow eyes compared to PACS (β = -2.98, SE = 0.249, P = 0.005) and higher iris volume increase with pupil dilation (β = -3.146, SE = 0.432, P = 0.015). Under dark conditions, angles of fellow eyes closed dramatically more than did those of PACS. Iris volume increase per millimeter of pupil dilation is an independent predictor of angle narrowing in darkness.

Choice of One-Piece Intraocular Lens Power and Changes of Anterior Chamber in Sulcus Implantation due to Posterior Capsular Rupture during Cataract Surgery

Choice of One-Piece Intraocular Lens Power and Changes of Anterior Chamber in Sulcus Implantation due to Posterior Capsular Rupture during Cataract Surgery

Does lens status affect the course of early intraocular pressure and anterior chamber changes after intravitreal injection?

This study aimed to observe changes in anterior chamber parameters and the course of intraocular pressure (IOP) after injection of 0.1 ml intravitreal triamcinolone acetonide (TA) and to determine differences between phakic and pseudophakic eyes without vitreous reflux. A prospective observational clinical trial was conducted with 89 patients who received an intravitreal injection of TA and did not display vitreous reflux. Intraocular pressure measurements were made before injection and at 3, 10, 20, 30 and 40 mins after injection. Pentacam measurements were made before injection and at 5, 15, 30 and 45 mins after injection. Anterior chamber depth (ACD) and anterior chamber volume (ACV) were significantly greater in pseudophakic eyes than in phakic eyes at all measurement time-points (p < 0.001). There was a decrease in both ACD and ACV at 5 mins after injection, and a gradual increase to normal values was observed at 15, 30 and 45 mins after injection in all study eyes. Compared with pre-injection measurements, changes in ACD and ACV were statistically significant at each time-point in both phakic and pseudophakic eyes (p < 0.001). A significant increase in IOP within 3 mins of injection was observed in both groups and a more rapid decrease 10 mins after injection was observed in pseudophakic eyes. The differences in IOP between phakic and pseudophakic eyes at all measurement time-points, except baseline and 3 mins after injection, were statistically significant (p < 0.001). Intraocular pressure < 30 mmHg and < 24 mmHg was recorded in all pseudophakic eyes at 10 and 20 mins after intravitreal injection, respectively. Following intravitreal injection of 0.1 ml TA, without vitreous reflux, IOP decreased to safe levels more quickly in pseudophakic eyes than in phakic eyes. Although there were more pronounced changes in anterior chamber parameters in pseudophakic eyes, these changes were reversible without any residual clinical significance.

Evaluation of anterior segment parameter changes using the Pentacam after uneventful phacoemulsification

This study set out to evaluate the influences of uneventful phacoemulsification on the anterior segment parameters obtained with the Pentacam rotating Scheimpflug camera and intraocular pressure (IOP). A total of 42 eyes of 34 patients (26 men, eight women) were evaluated preoperatively, and at 1, 3 and 6 months postoperatively with the Pentacam. Intraocular pressure was measured with the Goldmann applanation tonometer. The non-parametric paired t-test was used to compare preoperative and 1-, 3- and 6-month postoperative measurements of anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA) width, central corneal thickness (CCT), the central 3-, 5- and 7-mm corneal volume (CV), pupil size, and IOP. Pearson's correlation test was used to evaluate the relationships between IOP and ACD, ACV and ACA width. The differences between ACD, ACV, ACA and IOP values taken preoperatively and those taken postoperatively at 1, 3 and 6 months were statistically significant (p<0.05). The differences between CCT, central 3-, 5- and 7-mm CV, and pupil size measurements taken preoperatively and those taken postoperatively at 1, 3 and 6 months were not statistically significant (p>0.05). The decrease in IOP was not correlated with the changes in ACD, ACV and ACA (p>0.05). Uneventful phacoemulsification significantly reduced IOP, increased ACD and ACV, and widened the ACA. However, alterations in CV, CCT and pupil size values were not statistically significant. Alterations in ACD, ACV, ACA and IOP remain stable after the first month of surgery.

Spontaneous cataract formation in DBA/2J mice

Abstract Purpose DBA/2J mouse develop spontaneously changes in anterior chamber like pigment dispersion syndrome, iris atrophy, posterior synechiae leading to IOP increase. Additionally, there are observations suggesting cataract formation. The aim of this study was to describe features of cataract formation in DBA/2J mice. Moreover, presence and pattern of the L‐ kynurenine aminotransferases (KAT I , II and III) immunoreactivity in the cataractous lens of DBA/2J mice was investigated. Methods Immunohistochemistry was conducted using polyclonal antibodies against KAT I, II and KAT III on 18 cataractous lenses of 8‐, 11‐ and 24‐month old DBA/2J mice (6 in each group). All the sections of the lens were stained with Periodic Acid – Schiff (PAS), and normal anatomy of the anterior segment of the eye was confirmed. Moreover, all the animals subjected to the study were examined using slit lamp and anterior chamber photography. Results As observed clinically, the animals developed cataract during aging. PAS staining revealed presence of lens opacification. Immunohistochemical analysis revealed presence of KAT I, II and KAT III in the extracellular structures of cataract showing specific pattern of the stain. In cortical cataract the immunoreactivity was observed on cortical lens fibres. In nuclear cataract, KAT II revealed stronger and diffused staining than KAT I. Additionally both KATs showed more pronounced staining at the edge of small clefts. Conclusion Manifestation of L‐kynurenine aminotransferases in extracellular matrix during cataract formation in DBA/2J mice suggests that products of L‐kynurenine pathway might be involved in mechanisms of cataractogenesis in this animal model.

Optical Coherence Tomography Assessment of Angle Anatomy Changes After Cataract Surgery

To evaluate changes in anterior chamber (AC) morphology induced by cataract extraction using anterior segment optical coherence tomography (OCT). Prospective comparative observational case series. Thirty-two eyes of 32 patients underwent OCT imaging of the angle before and after cataract surgery. Anterior chamber depth (ACD), angle opening distance at 500 microm (AOD(500)) and trabecular-iris space at 500 microm (TISA(500)) were measured pre- and postoperatively. Preoperative lens thickness (LT) and lens position (LP) were calculated. ACD, AOD(500), and TISA(500) increased significantly after cataract extraction (P < .001). Preoperatively, ACD and LT highly correlated (P = .0083) as did ACD and TISA(500) (P = .0001). TISA(500) correlated with LP (P = .0001) but not with LT (P = .74). Changes in angle morphology after cataract surgery can be imaged and objectively quantified by anterior segment OCT. Lens position may have a greater influence on angle width than LT.

Microfluctuations of steady‐state accommodation measured with ultrasonography

Over the past 30 years investigators have noted fluctuations in accommodation when the eye views a stationary target. These microfluctuations have been studied mainly with the use of infrared optometers. Two dominant components have been found: a low frequency component (LFC; 0.05-0.5 Hz) and a high frequency component (HFC; 1.0-2.2 Hz). The LFC probably has a neurological origin. The HFC is supposed to be related to the arterial pulse. The aim of this study was to investigate accommodative fluctuations and gain more information about their origin by using a non-optical method. We used continuous ultrasonographic biometry to measure changes in anterior chamber (AC) depth, lens thickness and vitreous length during steady-state accommodation. Simultaneously, the electrocardiogram (ECG) was recorded. Changes in axial length were calculated offline by taking the sum of the changes in the three intraocular distances. Results show that fluctuations with an LFC were present in all three intraocular distances but not in the axial length, proving that only the lens was involved. In contrast with the findings of investigators using optical methods, no HFC was present in fluctuations of AC depth and lens thickness. However, a small HFC was found in registrations of the vitreous and axial length, which appeared to correspond with the heart rate.

Microfluctuations of steady-state accommodation measured with ultrasonography

Over the past 30 years investigators have noted fluctuations in accommodation when the eye views a stationary target. These microfluctuations have been studied mainly with the use of infrared optometers. Two dominant components have been found: a low frequency component (LFC; 0.05–0.5 Hz) and a high frequency component (MFC; 1.0–2.2 Hz). The LFC probably has a neurological origin. The HFC is supposed to be related to the arterial pulse. The aim of this study was to investigate accommodative fluctuations and gain more information about their origin by using a non-optical method. We used continuous ultrasonographic biometry to measure changes in anterior chamber (AC) depth, lens thickness and vitreous length during steady-state accommodation. Simultaneously, the electrocardiogram (ECG) was recorded. Changes in axial length were calculated offline by taking the sum of the changes in the three intraocular distances. Results show that fluctuations with an LFC were present in all three intraocular distances but not in the axial length, proving that only the lens was involved. In contrast with the findings of investigators using optical methods, no HFC was present in fluctuations of AC depth and lens thickness. However, a small HFC was found in registrations of the vitreous and axial length, which appeared to correspond with the heart rate.

Anterior chamber depth alteration after retinal photocoagulation.

Anterior chamber shallowing is a syndrome that may occur after retinal photocoagulation for diabetic retinopathy. Angle closure glaucoma may occur. Peripheral iridectomy is not indicated, as the condition is self-limited and will resolve with or without medical therapy within a few days. A vascular occlusive phenomenon leading to congestion in the choroidal system is postulated as the cause of this phenomenon. The ciliary body may be shifted anteriorly and rotated inwardly to produce the anterior chamber changes observed.