Effect of cycloplegia on axial length and anterior chamber depth measurements in children

Cheung, Sin Wan; Chan, Rufina; Cheng, Roy; Cho, Pauline

doi:10.1111/j.1444-0938.2009.00419.x

Cited by 48 publications

(51 citation statements)

References 18 publications

(71 reference statements)

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“…Sheng et al [8] found that cycloplegia had no significant effect on IOL Master AL measurements but produce a significant increase in ACD as measured with the IOLMaster. Cheung [9] found that the effect of cycloplegia on AL measurement with IOLmaster was insignificant in children aged from seven to 15 years; meanwhile, ACD measurement was significantly affected by cycloplegia. Huang et al [10] found that cycloplegia This device has also been found to provide repeatable, reproducible measurements and can be used interchangeably with Sirius (Scheimpflug camera and Placido-disk topography device) for CCT, ACD, mean K, and WTW [11].…”

Section: Discussionmentioning

confidence: 97%

The effect of pupillary dilatation on IOL power measurement by using the IOLMaster

2015

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The aim of this study is to assess the agreement of IOL power and ocular biometry measurements before and after pupillary dilatation by using the IOLMaster. This was the prospective nonrandomized cohort study. Measurements were taken with the IOLMaster (®) (Carl Zeiss Meditec AG, Jena, Germany) from healthy volunteers at the Department of Ophthalmology, King Chulalongkorn Memorial Hospital. Axial length (AL), keratometry both flattest and steepest (K1, K2), and anterior chamber depth (ACD) were measured before and after the dilatation of the pupil with 1 % tropicamide. The IOL power was calculated using the Sanders-Retzlaff-Kraff/Theoretical (SRK/T) formula. The mean difference of each parameter was assessed by Bland-Altman plot analysis. 384 eyes from 195 healthy volunteers were measured. The mean age of the patients was 52.39 ± 1.02 years (range 21-79). Pupillary dilatation had no significant effect on AL (p = 0.07), keratometry [steepest K (p = 0.95) and flattest K (p = 0.17)], and IOL power (Alcon SN60WF) (p = 0.40) obtained from the IOLMaster. However, ACD was significantly increased post-dilatation (p < 0.05). The Bland-Altman plot indicated good concordance in nearly all parameters except ACD. For ACD measurements, the 95 % limit of agreement between pre-dilatation and post-dilatation was -0.47 to 0.23 mm; therefore, 92.2 % of the measurement differences were with a LoA of -0.47 to 0.23 mm. There were no eyes that could not be measured by the IOLMaster. The dilatation of the pupil had no significant effect on AL, keratometry measurements, and SRK/T calculated IOL power. However, the ACD significantly increased post-dilatation.

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Section: Discussionmentioning

confidence: 97%

The effect of pupillary dilatation on IOL power measurement by using the IOLMaster

2015

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“…Secondly, we only analyzed the postcycloplegic ACD in all subjects. A previous study found that the ACD could be increased by 0.05 to 0.06 mm after cycloplegia [23] but as our population consisted of children aged 4 to 18, the accommodative power would vary considerably; thus, the authors decided that using a standardized postcycloplegic ACD measurement in all subjects would bring more consistency to our comparisons. Thirdly, the association between ACD and the inferior and global RNFL was only a weak correlation, and larger scale studies are warranted to establish the clinical significance of such association.…”

Section: Discussionmentioning

confidence: 99%

The Anterior Chamber Depth and Retinal Nerve Fiber Layer Thickness in Children

Lee

Yau

Woo

et al. 2014

The Scientific World Journal

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Purpose. To investigate the correlation of anterior chamber depth (ACD) with the peripapillary retinal nerve fiber layer (RNFL) thickness, age, axial length (AL), and spherical equivalent in children. Subjects. Consecutive subjects aged 4 to 18 were recruited. Visually disabling eye conditions were excluded. Only the right eye was included for analysis. The ACD was correlated with RNFL thickness, age, spherical equivalent, and AL for all subjects. Subjects were then divided into 3 groups based on their postcycloplegic spherical equivalent: myopes (<−1.0 D), emmetropes (≥−1.0 to ≤+1.0 D), and hyperopes (>+1.0 D). The ACD was compared among the 3 groups before and after age adjustment. Results. In 200 subjects (mean age 7.6 ± 3.3 years), a deeper ACD was correlated with thinner global RNFL (r = −0.2, r 2 = 0.06, P = 0.0007), older age (r = 0.4, r 2 = 0.1, P < 0.0001), myopic spherical equivalent (r = −0.3, r 2 = 0.09, P < 0.0001), and longer AL (r = 0.5, r 2 = 0.2, P < 0.0001). The ACD was deepest in myopes (3.5 ± 0.4 mm, n = 67), followed by emmetropes (3.4 ± 0.3, n = 60) and then hyperopes (3.3 ± 0.2, n = 73) (all P < 0.0001). After age adjustment, myopes had a deeper ACD than the other 2 groups (all P < 0.0001). Conclusions. In children, a deeper ACD was associated with thinner RNFL thickness, older age, more myopic spherical equivalent, and longer AL. Myopes had a deeper ACD than emmetropes and hyperopes.

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“…Since the sub-foveal choroid increased in thickness by 14 μm and the axial length decreased by 6 μm 60 minutes after homatropine instillation, the unaccounted 8 μm may be the result of the biomechanical forces on the globe associated with ciliary muscle relaxation and changes in the iris that also led to significant deepening of the anterior chamber and lens thinning. Previous animal (Nickla and Schrödl, 2012;Lin et al, 1996;Schmid and Wildsoet, 1996) and human (Drexler et al, 1997;Cheung et al, 2009) studies have also reported a significant variation in the anterior chamber depth and lens thickness measurements after the administration of muscarinic antagonists or surgical modification of parasympathetic input to the eye, with trends similar to the results obtained in our study. Pharmacologic blockade of cholinergic transmission resulted in significant enlargement of anterior chamber depth and thinning of the lens.…”

Section: Discussionsupporting

confidence: 81%

The Influence of the Autonomic Nervous System on the Human Choroid

Sander¹

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v AbstractThe impact of myopia is greater than just its optical consequences and in severe cases it can lead to a loss of vision. It is a highly prevalent eye disorder, with about one third of the population worldwide affected by this refractive error. Despite extensive research, the pathogenesis of myopia is still only partially understood. An improved knowledge of mechanisms underlying myopia is critical to developing new therapies to prevent myopia or to slow its progression.Although there is no fully effective and satisfactory myopia control treatment available, growing evidence has suggested that the choroid has a passive or active role in the regulation of eye growth and refractive error development. Numerous human and animal studies have shown that the retina can be moved forward or backward towards the image plane through changes in choroidal thickness, and these changes are likely to be associated in the longer term with eye growth and the development of refractive errors. As the choroid receives a rich innervation from the autonomic nervous system, many previous animal studies have utilized pharmacological agents and neurotoxins to elucidate the possible role of muscarinic signaling in the regulation of choroidal thickness, but only a few studies have investigated this issue in humans. An improved understanding of the mechanisms that control choroidal thickness may be important in developing new therapies for combating the development and progression of myopia.The research described in the thesis aimed to investigate the role of the autonomic nervous system in the control of choroidal thickness, axial length and the morphology In a series of experiments, we have confirmed that in humans under normal visual conditions, the parasympathetic nervous system is involved in the short-term regulation of subfoveal and parafoveal choroidal thickness, axial length and the morphology of the anterior sclera. The muscarinic blocker homatropine caused a significant subfoveal and parafoveal choroidal thickening, shortening of axial length, an enlargement of Schlemm's canal area and an increase in thickness of the conjunctival/episcleral complex. On the other hand, no notable changes in ocular parameters, except a decrease in the thickness of the conjunctival/episcleral tissues were found after instillation of the sympathomimetic drug phenylephrine.In an attempt to further improve our understanding of the myopigenic mechanisms influencing the thickness of the choroid in humans, we investigated the short-term influence of mixed interventions (positive and negative lens-imposed defocus / 2% homatropine) on choroidal thickness and axial length in emmetropic and myopic subjects. Homatropine prevented choroidal thinning in response to hyperopic defocus.This finding is consistent with the anti-myopia effects of muscarinic blockers and supports the potential importance of hyperopic defocus in the development of human myopia. By contrast, co-administration of homatropine with myopic defocus did not enhance the thicken...

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Effect of cycloplegia on axial length and anterior chamber depth measurements in children

Cited by 48 publications

References 18 publications

The effect of pupillary dilatation on IOL power measurement by using the IOLMaster

The effect of pupillary dilatation on IOL power measurement by using the IOLMaster

The Anterior Chamber Depth and Retinal Nerve Fiber Layer Thickness in Children

The Influence of the Autonomic Nervous System on the Human Choroid

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