Comparison of measurements of anterior chamber angle via anterior segment optical coherence tomography and ultrasound biomicroscopy

BACKGROUND Glaucoma is an irreversible optic neuropathy with the loss of visual field and decrease of vision.The variable clinical manifestations may result in differential diagnostic difficulties.The early screening and diagnosis of glaucoma are currently experiencing a demand for anterior segment analysis tools that can gather more information with one short measurement.Therefore,we analyzed the agreement,difference,and correlation of chamber angle parameters such as angel opening distance at 500μm(AOD500)and trabeculo-iris space area at 500μm^2(TISA500)measured by anterior segment optical coherence tomography(ASOCT)and ultrasound biomicroscopy(UBM).AIM To compare the differences,correlation,and agreement in measuring AOD500 and TISA500 by AS-OCT and UBM.METHODS Both AS-OCT and UBM were performed to measure AOD500 and TISA500 in 45 subjects(72 eyes).All subjects without glaucoma were collected from October 2015 to August 2016 at the Ophthalmology Department of the Fourth Affiliated Hospital of China Medical University.Data of the two groups(AOD500 and TISA500)were compared by nonparametric tests.Pearson correlative analysis and Bland-Altman analysis were used to compare the correlation and agreement.RESULTS There were no significant differences between AS-OCT and UBM in measuring AOD500(P1=0.110,P2=0.633,P3=0.078,and P4=0.474)and TISA500(P1=0.584,P2=0.889,P3=0.297,and P4=0.550)of the four quadrants of the anterior chamber angle.There was a high correlation in measuring AOD500(r1=0.562,r2=0.671,r3=0.635,and r4=0.720;P<0.001)and TISA500(r1=0.584,r2=0.889,r3=0.297,and r4=0.550;P<0.001).There was a good agreement in measuring AOD500 and TISA500 by the two modalities.CONCLUSION There is a high correlation and agreement between AOD500 and TISA500 measurements by AS-OCT and UBM.They are interchangeable under some circumstances.AS-OCT proves to be a better early screening tool for glaucoma.

Evaluation of the Anterior Chamber Angle Structures in Perinatal Infants Using a Wide-Field Digital Fundus Camera

Objective This study aimed to evaluate the ability of a digital fundus camera to observe the development of the anterior chamber angle(ACA)in premature infants.Methods Forty-eight eyes of preterm infants(n=48)were examined by a digital fundus camera to observe the development of the ACA.ACA grading was performed based on the visualization of the anterior chamber structures according to the Scheie Angle Depth Evaluating System.Results ACA images from all 48 infants were successfully acquired using RetCam3.The corrected gestational age ranged from 30 weeks to 49 weeks,which covered the period from 2 months preterm to>2 months post-term.As the corrected gestational age increased,the corrected gestational age grading was significantly decreased.The mean corrected gestational ages of the infants corresponding to the ACA classification from grade IV to grade 0 were 32.75±1.89,37.20±1.30,39.75±2.38,40.56±2.24,and 44.23±2.14 weeks,respectively,which were all significantly different(P<0.05).The regression analysis showed a linear correlation between the grading of the ACA and the corrected gestational age(R2=0.724,P=0.0001).Conclusion The ACA of a full-term newborn can be fully detected and evaluated by a digital fundus camera.For premature infants,part of the ACA is not visible physiologically;however,it should not be misdiagnosed as angle closure or a narrow angle.

Removal of intraocular foreign body in anterior chamber angle with prism contact lens and 23-gauge foreign body forceps

AIM：To introduce a novel approach in removal of anterior chamber angle foreign body（ACFB） using a prism contact lens and 23-gauge foreign body forceps.METHODS：Data of 42 eyes of 42 patients who had undergone removal of ACFB using a prism contact lens and 23-gauge foreign body forceps from January 2008 to October 2013 were collected and analyzed. Twenty eyes in group A received the conventional approach by using toothed forceps through corneal limbus incision, and 22 eyes in group B underwent the novel method through the opposite corneal limbus incision. RESULTS：The success rate of ACFB once removal was 75%（15/20） in group A, and 100%（22/22） in group B. The average operation time of group A was significantly longer compared with group B（34.9±9.88 min vs 22.13±8.85min; P〈0.05）. The average size of corneal limbus incision in group A was significantly larger than that of group B（4.85±1.89 mm vs 3.95±1.17 mm; P〈0.05）. The corneal limbus incision suturing were conducted in all eyes in group A, and only 5 eyes in group B. CONCLUSION：Removal of ACFB using a prism contact lens and 23-gauge foreign body forceps is a safer, more effective, and convenient technique compared with the conventional approach.

Evaluation of Nasal and Temporal Anterior Chamber Angle with Four Different Techniques

Background: Anterior chamber angle (ACA) can be measured by many different techniques. In order for a technique to be a part of the routine eye examination, it has to be quick and easy in good agreement with gonioscopy both nasally and temporally. Aim: To investigate variation in ACA measurement between gonioscopy, van Herick technique, anterior segment optical coherence tomography (AS-OCT) and Sirius Scheimpflug-Camera both nasally and temporally. Method: The ACA of 50 eyes of 25 healthy subjects was measured with gonioscopy, van Herick technique, AS-OCT and Sirius Scheimpflug-Camera. The angle was measured both nasally and temporally. Results: No statistically significant difference could be found between gonioscopy, van Herick technique and AS-OCT either nasally or temporally. The Sirius Scheimpflug-Camera on the other hand showed statistically significant difference to gonioscopy (p < 0.0001) both nasally (p = 0.03, p = 0.001, p < 0.0001) and temporally (p = 0.0002, p = 0.001, p Conclusion: This study showed good agreement between three of the four techniques. ACA measurements obtained by the Sirius Scheimpflug-Camera should therefore not be considered interchangeable with those obtained by the remaining three methods.

Comparison of phacotrabeculectomy and sequential surgery in the treatment of chronic angle-closure glaucoma coexisted with cataract

AIM： To compare the safety and effectiveness of phacotrabeculectomy versus sequential surgery in chronic angle-closure glaucoma（CACG） with coexisting cataract.·METHODS： One hundred and sixty-two CACG patients（162 eyes） were retrospectively analyzed. Of them, 87patients（87 eyes） in group A had underwent phacotrabeculectomy with intraocular lens（IOL）implantation, and 75 patients（75 eyes） in group B had underwent sequential surgery with IOL implanted. Best-corrected visual acuity（BCVA）, intraocular pressure（IOP）, complications and anterior chamber angle（ACA）were measured.· RESULTS： Demographic characteristics of the two groups were similar. A mean follow-up period was 15±6mo（range 13 to 24mo）, a mean IOP of 12.14 ±5.32 mm Hg in group A and 11.38 ±4.06 mm Hg in group B（P =0.84） at the last follow up. The Kaplan-Meier analysis revealed that the cumulative probability of success in both groups was similar（P =0.61）. Anterior uveitis and hypotony were the most common complications in group A, whereas group B experienced shallow anterior chamber with trabeculectomy. With the exception of anterior uveitis, no complications occurred to 11 trabeculectomized eyes. All postoperative measurements of anterior chamber showed statistically significant differences in each group according to the preoperative data（P〈 0.05）. However,fewer changes occurred in group B than in group A.· CONCLUSION： Phacotrabeculectomy and sequential surgery exhibit similar IOP reduction, visual recovery,and complications when treating CACG patients with cataract. However, for a wider ACA, phacotrabeculectomy has demonstrated higher effectiveness than sequential surgery.

Progression rate to primary angle closure following laser peripheral iridotomy in primary angle-closure suspects: a randomised study

AIM:To report the progression rate(PR)to primary angle closure(PAC)following laser peripheral iridotomy(LPI)in PAC suspects(PACS).METHODS:Prospective,randomized controlled interventional clinical trial conducted at the Handan Eye Hospital,China.Totally 134 bilateral PACS,defined as non-visibility of the posterior trabecular meshwork for≥180 degrees on gonioscopy were randomly assigned to undergo LPI in one eye.Gonioscopy and Goldmann applanation tonometry were performed prior to,on day 7 and 12 mo post LPI.RESULTS:Eighty of 134 patients(59.7%)could be followed up at one year.The mean intraocular pressure(IOP)in treated eyes was 15.9±2.6 mm Hg at baseline,15.4±3.0 mm Hg on day 7;16.5±2.9 mm Hg at one month,and 15.5±2.9 mm Hg at 12 mo;the IOP in untreated eyes was similar(P=0.834).One or more quadrants of the angle opened in 93.7%of the LPI treated eyes,but 67.0%(53/79)remained closed in two or more quadrants.The PR to PAC in untreated eyes was 3.75%and one developed acute angleclosure glaucoma(AACG);the PR to PAC in treated eyes was 2.5%and none had developed peripheral anterior synechia(PAS)or AACG.CONCLUSION:LPI can open some of the occludable angle in the majority of eyes with PACS,but 67%continue to have non-visibility of the trabecular meshwork for over 180 degrees.

Pressure Changes in Patients with Chronic Renal Failure Undergoing Hemodialysis

Purpose: To determine the effects of hemodialysis on intraocular pressure (IOP) and to evaluate the correlation of IOP changes with anterior chamber angle anatomy. Patients and Methods: The study included 80 eyes of 40 patients with chronic renal failure (CRF) undergoing hemodialysis at the High Technology Medical Center between October 2018 and October 2021. Hemodialysis (HD) was performed 3 times a week and the duration of the procedure was 3 - 5 hours. The enrolled patients were grouped according to the width of the anterior chamber angle. IOP was evaluated at three different times during HD. Intraocular pressure was measured in both eyes in an upright sitting position with iCare tonometer. Results: According to the study results, there was no statistically significant difference in the axial length between the three measurements (p = 0.232). In patients with normal anterior chamber depth, IOP decreased significantly (68.75%) or did not show any changes in their IOP during or after the session. In patients with moderate narrow-angle (22.5%), IOP revealed no statistically significant differences. In patients with narrow-angle (8.75%), there was a marked increase in IOP. Changes in intraocular pressure were correlated with the anatomy of the anterior chamber angle. Loss in body weight as a result of hemodialysis was statistically important (p Conclusion: A significant increase in mean was revealed during and after hemodialysis in patients with extremely narrow-angle in comparison to eyes with wide or moderately anterior chamber angle. Eyes with shallow anterior chambers are at risk of having impaired aqueous humor outflow facilities and, as a result, significantly increase IOP during HD. Because of the high prevalence of narrow angles in the Caucasian population, it is of clinical importance to investigate the IOP changes in patients on HD. The results of our study support the idea that iridocorneal angle anatomy is affecting IOP fluctuation occurring in patients with ESRD undergoing HD.

Changes in symmetry of anterior chamber following routine cataract surgery in non-glaucomatous eyes

Background:To assess minimum and maximum changes in anterior chamber dimensions following routine cataract surgery in non-glaucomatous eyes.Methods:Forty-two eyes(42 participants)underwent routine cataract surgery with same surgeon and were assessed preoperatively,1,3,6 and 12 months postoperatively.Primary outcome measure:Angle-to-angle diameter(AAD)(at 0-180°,45-225°,90-270°,135-315°),Anterior-chamber-angle(ACA)(at 0°,45°,90°,135°,180°,225°,270° and 315°)and central anterior chamber depth(ACD)at all visits.Secondary outcome measures:relationship to axial length(AL).Results:The mean AAD and ACA increased post-operatively in all meridians at all visits postoperatively.At 12 months,there was a maximum change in AAD in horizontal meridian(506.55±468.71μm)and least in vertical meridian(256.31±1082.3μm).The mean percentage increase in ACA postoperatively was least at 90o(5%increase compared to 29–35%elsewhere).Central ACD deepened at all postoperative visits and this did not change over 12 months.There was no correlation between AAD,ACA and ACD with AL at any visit.Conclusion:The AAD,ACA and ACD increases following cataract surgery in non-glaucomatous eyes,but at 12 months increase in AAD is least in vertical compared to horizontal meridian.Also,ACA was narrower(only 5%increase)superiorly compared to elsewhere(29–35%increase in ACA).This may have implications with regards to surgeries performed in the anterior chamber and corneal endothelial cell loss.

Associations of lens thickness and axial length with outcomes of laser peripheral iridotomy

AIM:To investigate the association of axial length(AL),lens thickness(LT),and lens vault(LV)with postoperative anterior chamber angle metrics after laser peripheral iridotomy(LPI).METHODS:Prospective observational study of 69 patients(97 eyes)were diagnosed as primary angle-closure suspect(PACS),primary angle closure(PAC)or primary angle-closure glaucoma(PACG).AL,LT,anterior central chamber depth(ACD),angle opening distance(AOD),trabecular iris angle(TIA),and angle recess area(ARA)were measured before and 1 wk after LPI.The association between AL,LT,LV with ACD,AOD,TIA,ARA were analyzed by comparing the differences between preoperative and postoperative measurements for anterior segment biometric parameters.RESULTS:ACD,AOD,TIA,and ARA were significantly increased after LPI(all P<0.05).Greater LT was significantly associated with greater postoperative increases in ACD,AOD,TIA,and ARA(all P<0.05).AL was not significantly associated with changes of anterior segment biometric parameters.Greater LV was significantly associated with greater postoperative increases in ACD,AOD,and TIA(all P<0.05),but was not significantly associated with changes of ARA.CONCLUSION:Greater baseline LT and LV measurements are associated with greater increases in anterior segment biometric parameters after laser peripheral iridotomy.AL are not associated with the change of anterior segment biometric parameters.