Assessment of the anterior chamber parameters after laser iridotomy in primary angle close suspect using Pentacam and gonioscopy

AIM:To evaluate the changes in the anterior segment parameters of the subjects with primary angle closure suspect(PACS) before and after laser iridotomy(LI) using the Pentacam and gonioscopy. METHODS:Forty-eight eyes of 48 PACS were included.Anterior chamber angle(ACA),central anterior chamber depth(ACD),anterior chamber volume(ACV) and central corneal thickness(CCT) were recorded from the Pentacam before and one month after LI.ACA was graded according to Shaffer classification using Goldmann gonioscopy.RESULTS:ACA increased significantly from 25.59±4.41 to 26.46±4.33 degrees(P=0.009) and ACV changed from 85.97±16.07mm3to 99.25±15.83mm3(P=0.000).The changes in ACD,CCT and intraocular pressure were non-significant(P】0.05).Gonioscopy showed significant widening of the Shaffer angle in 4 quadrants(P【0.001).CONCLUSION:Pentacam can serve as the objective instrument in assessing the efficacy of LI.

Comparison of laser iridotomy using short duration532-nm Nd: YAG laser (PASCAL) vs conventional laser in dark irides

AIM: To evaluate the outcome of laser iridotomy using532-nm Nd: YAG laser(PASCAL) with short pulse duration and Nd: YAG laser compared to conventional combined laser iridotomy.METHODS: Retrospective, nonrandomized, comparative case series. Forty-five eyes of 34 patients underwent laser iridotomy. Twenty-two eyes underwent iridotomy using short duration PASCAL and Nd: YAG laser, and 23 eyes underwent iridotomy using conventional combined laser method. The average settings of PASCAL were60 μm and 700-900 m W with a short duration of 0.01 s to reduce the total applied energy. The conventional laser was 50 μm and 700-900 m W for 0.1s. After photocoagulation with these laser, the Nd: YAG laser was added in each group. Endothelial cell counts of preiridotomy and 2mo after iridotomy were measured and compared.RESULTS: All eyes completed iridotomy successfully.The total energy used in the PASCAL group was 1.85 ±1.17 J. Compared to conventional laser 13.25 ±1.67 J, the energy used was very small due to the short exposure time of PASCAL. Endothelial cell counts were reduced by0.88% in the PASCAL group and 6.72% in the conventional laser group(P =0.044). The change in corneal endothelial cell counts before and after iridotomy was significant in conventional combined laser iridotomy group(P =0.004).CONCLUSION: Combined PASCAL and Nd:YAG laseriridotomy is an effective and safe technique in the dark brown irides of Asians. Furthermore, the short duration of exposure in PASCAL offers the advantages of reducing the total energy used and minimizing the corneal damage.

Predictors of angle widening after laser iridotomy in Chinese patients with primary angle-closure suspect using ultrasound biomicroscopy

AIM:To assess the predictive value of baseline parameters of ultrasound biomicroscopy(UBM) for angle widening after prophylactic laser peripheral iridotomy(LPI) in patients with primary angle-closure suspect(PACS).METHODS:Angle-opening distance(AOD),trabecular iris angle(TIA),iris thickness,trabecular-ciliary process angle,and trabecular-ciliary process distance were measured using UBM performed before and two weeks after LPI.Iris convexity(IC),iris insertion,angulation,and ciliary body(CB) size and position were graded.Uni-and multivariate regression analyses were used to determine factors predicting the change in AOD(ΔAOD500,calculated as an angle width change before and after LPI) in all quadrants and in subgroup quadrants based on IC.RESULTS:In 94 eyes of 94 patients with PACS,LPI led to angle widening with increases in AOD500 and TIA(P<0.01).Multivariable regression analysis showed that IC(P<0.001),CB position(P=0.007) and iris insertion(P=0.049) were significantly predictive for ΔAOD500.All quadrants were categorized into extreme IC(27.8%),moderate IC(62.3%),and absent IC(9.9%) subgroups.The AOD500 increased by 220% and no other predictive factor was found in the extreme IC quadrants.The AOD500 increased by 55%,and baseline iris angulation was predictive for smaller changes in ΔAOD500 in the moderate IC quadrants.CONCLUSION:In PACS patients,quadrants with greater iris bowing predict substantial angle widening after LPI.Quadrants with a flatter iris,anteriorly positioned CB,and basal iris insertion are associated with less angle widening after LPI.Quadrants with iris angulation as well as a flatter iris configuration predict a smaller angle change after LPI.

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.

Comparison of ultrasound biomicroscopy and spectraldomain anterior segment optical coherence tomography in evaluation of anterior segment after laser peripheral iridotomy

AIM：To quantitatively assess narrow anterior chamber angle using spectral-domain anterior segment optical coherence tomography（SD-AS-OCT） and ultrasound biomicroscopy（UBM）,and to evaluate the correlations and consistency between SD-AS-OCT and UBM.· METHODS：Fifty-five eyes from 40 patients were examined.Patients were diagnosed with primary angleclosure glaucoma（PACG） remission（11 eyes from 8patients）,primary angle closure（PAC,20 eyes from 20patients） and PAC suspect（24 eyes from 12 patients）.Each eye was examined by SD-AS-OCT and UBM after laser peripheral iridotomy（LPI）.The measurements of SD-AS-OCT were angle open distance（AOD）,anterior chamber angle（ACA）,trabecular iris angle（TIA）,and trabecular iris space area（TISA）.UBM measurements were AOD and TIA.Correlations of AOD500 and TIA500 between UBM and AS-OCT were assessed.All parameters were analysed by SPSS 16.0 and MedCalc.· RESULTS：ACA,TIA and AOD measured by SD-ASOCT reached a maximum at the temporal quadrant and minimum at the nasal quadrant.Group parameters of AOD500 and AOD750 showed a linear positive correlation,and AOD750 had less variability.UBM outcomes of AOD500 and TIA500 were significantly smaller than those of SD-AS-OCT.The results of the two techniques were correlated at the superior,nasal and inferior quadrants.CONCLUSION：Both UBM and SD-AS-OCT are efficient tools for follow-up during the course of PACG.We recommended using parameters at 750 μm anterior to the sclera spur for the screening and follow-up of PACG and PAC.The two methods might be alternatives to each other.

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.

Efficacy of laser peripheral iridoplasty and iridotomy on medically refractory patients with acute primary angle closure： a three year outcome

Background Argon laser peripheral iridoplasty （ALPI） is proved to be effective in lowering intraocular pressure （lOP） of patients with mild acute primary angle closure （APAC）. It is unclear whether this laser treatment is equally efficient in managing patients with severe APAC. This study aimed peripheral iridotomy （LPI） on patients with refractory APAC, therapy. to evaluate the IOP-lowering efficacy of ALPI and laser who have previously responded poorly to intensive medical Methods Thirty-six patients （8 men and 28 women） were identified as medically refractory APAC, who still had ocular pain, red eye, hazy cornea, closed anterior chamber （AC） angle, and lOP of not less than 21 mmHg after two days or more of anti-glaucoma medication. All enrolled patients underwent ophthalmologic examinations including measurement of visual acuity （VA）, best corrected VA （BCVA）, lOP, biomicroscopy, and gonioscopy followed by ALPI immediately in the APAC eye and LPI in both eyes. Results All patients were affected unilaterally, with average age of （54.6±11.7） （range, 37.0-75.0） years old. The mean lOP value of the affected eyes dropped from （31.6±7.7） （range, 21.0-39.0） mmHg at enrollment to （18.4±8.7） （range, 10.0-27.0） mmHg 2 hours after ALPI. At follow-up day 7, the mean lOP value maintained at （14.8±4.2） （range, 9.0-21.0） mmHg, which was significantly different （P=0.000） compared with baseline. The average decrease of lOP in the APAC eyes was （16.8±7.4） （range, 12.0-21.0） mmHg. At follow-up three years later, the mean lOP of the APAC eyes stabilized at （16.3±3.2） （range, 9.0-20.0） mmHg with at least 180° of AC angle opened. Conclusion ALPI and LPI lower the lOP of medically refractory cases of APAC though they have responded poorly to anti-glaucoma medication.