Prevention of Blinking Alters Iris Configuration in Pigment Dispersion Syndrome and in Normal Eyes

Liebmann, Jeffrey M.; Tello, Celso; Chew, Sek-Jin; Cohen, H; Ritch, Robert

doi:10.1016/s0161-6420(95)31001-9

Cited by 85 publications

(58 citation statements)

References 18 publications

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“…Considerable insight may be drawn from comparison to a previous study of iris contour during sustained prevention of blinking (Liebmann et al 1995). In that study, as in the current one, steady increase in iris curvature was observed, and the rates were similar.…”

Section: Discussionsupporting

confidence: 63%

“…The iris curvature was calculated by drawing a line connecting the most peripheral and most central points of the iris pigment epithelium, and then measuring the largest perpendicular distance (anterior/convex = positive, posterior/concave = negative) from the line to the iris pigment epithelium (Liebmann et al 1994;Liebmann et al 1995).…”

Section: Methodsmentioning

confidence: 99%

“…Iris bowing is largely eliminated in patients with PDS after a peripheral iridotomy when observed with ultrasound biomicroscopy (UBM) (Pavlin et al 1996). Normal subjects show a posterior shift in iris contour with accommodation (Liebmann et al 1995;McWhae et al 1996;Ueda et al 1997). Older patients show a pronounced decrease in posterior bowing following accommodation (Adam et al 2004), consistent with the reduced lens motion of presbyopia.…”

Section: Introductionmentioning

confidence: 99%

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Accommodation-induced changes in iris curvature

Dorairaj

Oliveira

Fose

et al. 2008

Experimental Eye Research

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Eyes were imaged using anterior segment ultrasound biomicroscopy to compare alterations in iris contour following the onset of accommodation in eyes with narrow angles, pigment dispersion syndrome, and controls. A radial perpendicular image in the horizontal temporal meridian was obtained for one eye while the subject focused on a distant target (~6m, unaccommodated state) with the fellow eye. The subject then focused steadily on a near target (~0.33m, accommodated state) for three minutes. Images were acquired at 0, 1, 2, and 3 minutes. Iris curvature was determined by measuring the maximum distance between the posterior iris surface and a line from the iris root to the first point of contact between the iris and lens. In control subjects (n = 22), iris curvature decreased immediately after the onset of accommodation, but not significantly (p = 0.49), from 246 ± 37 µm (mean ± SEM) to 205 ± 82 µm; curvature increased after three minutes of accommodation to 298 ± 57 µm (p = 0.10 vs. onset of accommodation). Eyes with pigment dispersion syndrome (n = 15) exhibited curvatures of 60 ± 79 µm when unaccommodated, −3 ± 83 µm immediately after accommodation (p = 0.12), and 146 ± 94 µm (p = 0.01) three minutes later. Eyes with narrow angles (n = 16) exhibited curvatures of 449 ± 45 µm when unaccommodated, 414 ± 46 µm immediately after accommodation (p = 0.37), and 523 ± 40 µm (p < 0.01) three minutes later. The results confirm the time-dependent nature of iris contour response, with significant differences observed between the initial observation after accommodation and the observation three minutes later. The largest drop in curvature immediately after accommodation and the most rapid increase in curvature during subsequent observation were seen in the PDS subjects. We suspect that the more rapid increase in curvature in the PDS subjects is due to the elevated anterior-chamber pressure caused by the "reverse pupillary block" effect.

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Section: Discussionsupporting

confidence: 63%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Accommodation-induced changes in iris curvature

Dorairaj

Oliveira

Fose

et al. 2008

Experimental Eye Research

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“…The act of blinking acts as a mechanical pump to push aqueous from the posterior to the anterior chamber. 4,7 Once in the anterior chamber, backflow of aqueous is prevented by the abnormal iridolenticular contact, which produces a reverse papillary block, further enhancing iris concavity. The liberated pigment blocks the trabecular meshwork causing rise in intraocular pressure and glaucoma.…”

Section: Discussionmentioning

confidence: 99%

Pigment dispersion syndrome

Sandhya¹,

Krishna²,

Bhaskar³

2013

JCSR

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We report of the rare occurrence of pigment dispersion syndrome (PDS) with posterior subcapsular cataract in both eyes in a young male patient. The patient presented with complaints of progressive decrease in vision of one year duration. The patient also had high myopia with mild iridodonesis, phacodonesis and anterior insertion of zonules. Classical signs of PDS like Krukenberg's spindle on the posterior corneal surface were evident on slit lamp examination; transillumination defects in the iris could not be elicited by retroillumination as the iris was heavily pigmented. Gonioscopy revealed heavy and uniform pigmentation of trabecular meshwork. Evidence of a characteristic iris configuration on optical coherence tomography (OCT), namely, posterior bowing of iris in the mid periphery suggested the diagnosis of PDS. This case highlights the importance of OCT in identifying the iris configuration characteristically seen in PDS even in the absence of transillumination defects in the iris and reiterates the need to look for subtle signs like phacodonesis which are important when surgical intervention is planned.

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“…Prevention of blinking causes reversal of iris configuration. 5 Lance Liu et al 6 have reported that the iris remains planar with continuous blinking and controlled accommodation and that the posterior curvature of the iris is induced and probably maintained by accommodation.…”

Section: Discussionmentioning

confidence: 99%