Iris Crypts Influence Dynamic Changes of Iris Volume

Chua, Jacqueline; Thakku, Sri Gowtham; Tun, Tin A.; Nongpiur, Monisha E.; Tan, Marcus; Girard, M; Wong, Tien Yin; Quah, Joanne Hui Min; Aung, Tin; Cheng, Ching‐Yu

doi:10.1016/j.ophtha.2016.06.034

Cited by 20 publications

(17 citation statements)

References 33 publications

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“…Iris crypts play a vital role in aqueous humor outflow by affecting the permeability of the anterior iris surface, the iris volume and curvature, and the uveoscleral and trabecular pathways [ 8 ]. Previous studies have shown that fewer iris crypts is a surrogate marker for a static biometric risk factor for angle closure [ 8 ].…”

Section: Discussionmentioning

confidence: 99%

“…The morphology of the iris was described, and a “boomerang-shaped” iris was defined as a “bended” iris shown in cross-section which is different from a normal straight phenotype. The iris crypts were graded in each eye using a slit lamp and a previously described grading system was used: grade 1 (no crypts); grade 2 (1–3 crypts); grade 3 (≥ 4 crypts, < 1 mm in diameter); grade 4 (≥ 4 crypts, ≥ 1 mm in diameter), and grade 5 (numerous crypts, > 1 mm in diameter, covering nearly the entire iris) [ 8 ]. The diameter and area of the SC, and the thickness, width, and area of the TM were measured manually by two independent observers (QL, WH) with the Image Processing and Analysis in Java (ImageJ) software ( www.imagej.nih.gov/ij/ ; National Institutes of Health, Bethesda, MD, USA).…”

Section: Methodsmentioning

confidence: 99%

“…Previous studies have demonstrated that broader peripheral anterior synechiae (PAS) can lead to a smaller reduction in IOP after phacoemulsification compared to that in eyes with fewer PAS [ 7 ]. The anterior positioning of the ciliary body and the dynamic physiological responses of the iris can also contribute to the narrowing of the chamber angle and possibly to PAS formation, as could be illustrated by medical imaging and iris crypts, respectively [ 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

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Morphological features of anterior segment: factors influencing intraocular pressure after cataract surgery in nanophthalmos

Lü

et al. 2020

Eye and Vis

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Purpose To investigate the anterior segment in nanophthalmic eyes and their association with intraocular pressure after cataract surgery. Methods Thirty-two nanophthalmic eyes (axial length [AL] < 18.5 mm) in 18 patients and 35 normal eyes (21 ≤ AL ≤ 24.5 mm) in 35 controls who had undergone uneventful cataract surgery were included. Swept-source optical coherence tomography was used to compare the anterior segment structures between the two groups. The associations between the anterior segment characteristics of nanophthalmic eyes and postoperative intraocular pressure (IOP) were also investigated. Results The IOP-lowering effect of cataract surgery was remarkably insufficient in nanophthalmic eyes. Peripheral anterior synechiae (PAS) were observed in 56% (18/32) of nanophthalmic eyes, and a characteristic boomerang-shaped iris was observed in 28% (9/32). The anterior surface of the iris seemed “smoother” in nanophthalmic eyes than in normal eyes. Schlemm’s canal (SC) diameter, SC area, trabecular meshwork (TM) thickness, TM width, and TM area were generally smaller in the nanophthalmic eyes. Younger age, higher preoperative IOP, broader PAS, and smaller SC area were main contributors to higher postoperative IOP. AL and SC diameter may also be of great importance in IOP prediction in patients without glaucoma surgery and PAS. Conclusions The morphological features of the anterior segment in nanophthalmic eyes are significantly different from those of normal eyes. Influencing factors such as age, AL, preoperative IOP, extent of PAS, SC and TM size could all be prognostic for IOP after cataract surgery in nanophthalmic eyes. Trial registration ClinicalTrails.gov, Trial registration number: NCT02182921, Registered 8 July 2014.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Morphological features of anterior segment: factors influencing intraocular pressure after cataract surgery in nanophthalmos

Lü

et al. 2020

Eye and Vis

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“…When we further adjusted for anterior chamber depth, the OR did not differ much—(OR 0.52; p=0.16). Nevertheless, iris crypt could still be a good surrogate for static biometric risk factors10 11 and more importantly, dynamic iris volume changes24 (see the following paragraph for details). Hence, our findings could have clinical implications towards prognosis, risk stratification and treatment of eyes with angle closure disease.…”

Section: Discussionmentioning

confidence: 99%

“…The lack of iris crypts may translate into loss of iris sponginess and leads to inability of the iris to lose aqueous humour during pupil dilation. Using AS swept-source OCT, we recently showed that irides with less crypts lost less iris volume on pupil dilation 24. In narrow angle eyes, this causes the iris with fewer crypts (featureless) to remain thickened, which may then block the trabecular meshwork leading to an acute rise in IOP and/or APAC attack 12.…”

Section: Discussionmentioning

confidence: 99%