scholarly journals Smaller Anterior Chamber Volume Is Associated With Higher Risk of Intraocular Pressure Elevation After Laser Peripheral Iridotomy

2020 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Rouxi Zhou ◽  
Fei Li ◽  
Kai Gao ◽  
Xiulan Zhang
2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Wakako Ikegawa ◽  
Takashi Suzuki ◽  
Koji Namiguchi ◽  
Shiro Mizoue ◽  
Atsushi Shiraishi ◽  
...  

Purpose. To quantify changes in anterior segment (AS) parameters after laser peripheral iridotomy (LPI) using AS-optical coherence tomography (OCT) of iris bombe. Method. AS images of eight eyes were captured before and after iris bombe and more than 2 weeks after LPI (post-LPI) using AS-OCT. We compared the following AS parameters: anterior chamber depth (ACD), anterior chamber volume (ACV), iris curvature (IC), iris thickness at 500 μm from the scleral spur (IT-1) in the middle between the iris root and pupillary margin (IT-2) and 500 μm from the pupillary margin (IT-3) to the anterior chamber angle (ACA) (angle opening distance [AOD750]), and trabecular iris space area. Results. Mean IT-1 and IT-3, but not IT-2, were lower after iris bombe (IT-1, P=0.001; IT-2, P=0.081; and IT-3, P=0.001). There were no significant differences between ACD at pre-LPI and before iris bombe (P=0.096). The mean ACV and AOD750 of iris bombe increased at post-LPI (ACV, P<0.01, and AOD750, P<0.05). The mean IT-1, IT-2, and IT-3 increased at post-LPI (all, P≤0.01). IC decreased at post-LPI (P<0.001), and ACD at post-LPI did not change. Conclusions. The iris extends and becomes thinner during iris bombe. LPI during bombe decreases the IC and increases the ACV and ACA.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Zhipeng Yan ◽  
Huamao Miao ◽  
Feng Zhao ◽  
Xiaoying Wang ◽  
Xun Chen ◽  
...  

Purpose. To investigate two-year outcomes of Visian Implantable Collamer Lens with a central hole (ICL V4c) implantation for correcting high myopia.Methods. Sixty-one eyes of 32 patients went through ICL V4c implantation. Safety, efficacy, predictability, and intraocular pressure were evaluated 2 years postoperatively. Anterior chamber volume (ACV), anterior chamber depth (ACD), anterior chamber angle width (ACAW), and vault were measured using a Scheimpflug tomography imaging system.Results. At 2 years, the spherical equivalent refraction decreased from preoperative −14.62 ± 4.29 D to −0.90 ± 0.95 D, with 79% of the eyes within ±0.50 D and 98% within ±1.00 D of the intended correction. The efficacy index was 1.03 ± 0.23, and the safety index was 1.24 ± 0.26. Corrected distance visual acuity (CDVA) remained unchanged in 23% of the eyes, 75% gained one or more lines of CDVA, and 2% lost one line. The ACV, ACD, and ACAW, respectively, decreased from 193.28 ± 29.15 mm3, 3.15 ± 0.23 mm, and 36.51 ± 6.54 degree to 112.48 ± 17.01 mm3, 2.99 ± 0.23 mm, and 22.54 ± 5.27 degree (p=0.0008,  0.008,  and  0.0003, resp.). Intraocular pressure was 15.39 ± 2.88 mmHg before surgery and was 15.86 ± 4.11 mmHg at 2 years (p=0.11).Conclusion. Implantation of ICL V4c is a safe, effective, and predictable procedure for correcting high myopia. Reduction of anterior chamber space after surgery did not induce intraocular pressure increase during the 2-year follow-up.


2011 ◽  
Vol 312-315 ◽  
pp. 737-742 ◽  
Author(s):  
Humberto Dória Silva ◽  
Luiz Cláudio Pereira Dória ◽  
Cristiana Pereira Dória ◽  
Cristiane Pereira Dória ◽  
Maria do Carmo Tatiana Dória Silva ◽  
...  

This work demonstrates the need for updated review of the mechanism of mass transport in the human cornea, to understand the deterioration of visual acuity and plan your recovery. It is the conclusion of a work for ten years for recovery of presbyopia of the first author, through exercise the extra-ocular and ciliary muscles. It is shown that intraocular pressure varies according to the direction of the visual axis and that this variation is part of the mechanism of forced convection for the transport of nutrients and drainage of secretions metabolic in cornea. In both eyes, seven pressure measurements are proposed at intervals of one hour, with the non-contact tonometer: The first measurement in the initial condition; The second measurement after relaxation of the eyes; The following measurement after an activity with the attachment point near of the two eyes; The last four are proposed out after two activities, in the limit of the direction of the right border and, also, in the limit of the direction of the left border of the field of binocular vision, considering the two alternatives near and far from the eyes. The oblique muscles contraction causes a reduction in the anterior chamber volume and, consequently, the intraocular pressure increases, however, when the oblique muscles relax the opposite occurs. It is considered that, after an hour, the intraocular pressure reaches dynamic equilibrium. To measure the pressure, the equilibrium condition of the anterior chamber volume is changed, the system undergoes a new transient dynamic. There should be no change in intraocular pressure equilibrium during one day, unless because of an external factor. To collect the data, it is proposed to use the system eye of the first author who has good binocular vision.


2016 ◽  
Vol 236 (1) ◽  
pp. 43-47 ◽  
Author(s):  
Hussam El Chehab ◽  
Emilie Agard ◽  
Aurélie Russo ◽  
Ygal Boujnah ◽  
Corinne Dot

The objective of this study was to assess the intraocular pressure (IOP) as well as the anatomical modifications of the anterior segment following an aflibercept injection. Patients underwent an aflibercept intravitreal injection (IVI) (0.05 ml) with a 30.5-gauge needle and an antireflux system. IOP was assessed before injection (T0), immediately after (T1), and 5 min (T5), 15 min (T15), and 45 min (T45) after the IVI. Before the IVI and immediately after the T1 measurement, a PENTACAM® acquisition was used to evaluate the anterior chamber parameters (anterior chamber volume, depth and measure of the iridocorneal angle). At T0, IOP was 12.9 ± 1.3 mm Hg. IOP significantly increased after IVI (42.7 ± 3 mm Hg, p < 0.001). IOP returned to baseline at T45 (13.0 ± 1.2 mm Hg, p = 0.877). Anterior chamber volume decreased after IVI (160.6 vs. 168.3 mm3, p = 0.002). No significant changes were found for iridocorneal angle and anterior chamber depth. Aflibercept IVI causes an acute increase in IOP over a short period without iridocorneal angle closure.


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