In vivo Observation of the Axial Movement of Intraocular Lenses through an Anterior Eye Segment Analysis System

Nakaizumi, Hiroko; Sasaki, Kohsuke; Sakamoto, Y.

doi:10.1159/000267203

Cited by 8 publications

(4 citation statements)

References 2 publications

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“…35 This does not hold true for humans, as evidenced by the lifelong presence of undiminished accommodative ciliary muscle contraction. Similarly, the observations of accommodative IOL optic movement in the pseudophakic eye 25,[36][37][38][39] also indirectly indicate the ciliary muscle and its restoring force (the choroid) are capable, even in advanced presbyopia. In addition, while the aging human ciliary muscle apex displaces anteriorly, 40 the rhesus ciliary muscle becomes fixed in a position far posteriorly.…”

Section: Discussionmentioning

confidence: 90%

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Magnetic resonance imaging of aging, accommodating, phakic, and pseudophakic ciliary muscle diameters

Strenk¹,

Strenk²,

Guo³

2006

Journal of Cataract and Refractive Surgery

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PURPOSE-To quantify in vivo accommodative changes in the aging human ciliary muscle diameter in phakic and pseudophakic eyes. METHODS-Images were acquired from 48 eyes of 40 people between the ages of 22 and 91 years, 1 eye of 32 phakic volunteers and both eyes of 8 patients who had monocular implantation of a single-piece AcrySof intraocular lens (IOL) (Alcon Laboratories). Images were acquired during physiological accommodation and with accommodation at rest, and the diameter of the ciliary muscle ring was measured. SETTING-Department RESULTS-Resultsshow the ciliary muscle remains active throughout life. The accommodative change in its diameter (mean 0.64 mm) (P<.00001) was undiminished by age or IOL implantation. Preliminary data showed that the accommodative decrease in muscle diameter in phakic and pseudophakic eyes was statistically identical. The phakic eyes had a marked decrease in ciliary muscle diameter with advancing age for both accommodative states (P<.000001 and P<.000001), which did not appear to be altered by IOL implantation. The lens equator was constant with age in the unaccommodated human eye, resulting in decreased circumlental space with advancing age in the phakic eyes.CONCLUSION-Although the undiminished ability of the ciliary muscle to decrease its diameter with accommodation can be relied on in strategies for presbyopia correction, even in advanced presbyopia, the decreasing circumlental space and its potential effects on zonular tension must also be considered.New strategies, including lens softening, lens refilling, scleral expansion, and potentially accommodating intraocular lenses (IOLs), are being developed to restore accommodation in presbyopic eyes. 1-11 Because a functioning ciliary muscle is key to each procedure or device, it is increasingly important to quantify in vivo accommodative changes in the aging ciliary muscle of phakic and pseudophakic eyes. Although the iris obscures direct observation of the ciliary muscle in the normal, intact human eye, magnetic resonance This ability to observe the geometric relationship of the accommodative structures with MRI has also provided the only statistically significant demonstration that the Helmholtz theory 24 of human accommodation is correct. Strenk et al. 21 found that in response to an accommodative stimulus, a decrease in the ciliary muscle ring diameter and the lens equatorial diameter occurred, with a corresponding increase in lens thickness. Although the lenticular changes decreased with advancing age, the accommodative change in the ciliary muscle ring diameter was undiminished throughout life, with a mean value of 0.661 mm. A possible trend toward a slight decrease in muscle contraction with advancing age was present but not statistically significant. However, only a limited number of people with advanced presbyopia were enrolled. The mean age of the 25 subjects in the study was 39.10 years (range 22 to 83 years). Only 1 subject was older than 62 years. Here, we expand the age range to 91 years and provide a more u...

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Section: Discussionmentioning

confidence: 90%

“…Reports of anterior and posterior optic movement with accommodative effort 25,[36][37][38][39] indicate some level of zonular tension is likely restored after IOL implantation as ciliary muscle effort apparently affects optic position. Magnetic resonance imaging can visualize the optic and haptics in relation to the accommodative structures.…”

Section: Discussionmentioning

confidence: 99%

Magnetic resonance imaging of aging, accommodating, phakic, and pseudophakic ciliary muscle diameters

Strenk¹,

Strenk²,

Guo³

2006

Journal of Cataract and Refractive Surgery

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“…Previous studies suggest that many factors are associated with apparent accommodation; these include pupil size, 11-13 myopic astigmatism, 14-17 longitudinal movement of the IOL, 23,24 and corneal multifocality. 25 More specifically, several studies report that some degree of astigmatism enhances apparent accommodation, even in eyes with a monofocal IOL.…”

Section: Discussionmentioning

confidence: 99%

Optimum target refraction for highly and moderately myopic patients after monofocal intraocular lens implantation

Hayashi

2007

Journal of Cataract and Refractive Surgery

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“…28,29 We measured the OS by applying the pharmacological method in which we calculated the difference in the ACD. 3,10,11,24,[30][31][32][33][34][35] Although this is an indirect method, it is well-accepted as it does not rely on patient compliance during the measurement procedure.…”

Section: Discussionmentioning

confidence: 99%

Anterior capsule cover and axial movement of intraocular lens

Nanavaty

Raj

Vasavada

et al. 2007

Eye

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Purpose To measure optic shift (OS) of a single piece monofocal intraocular lens (IOL) with varying relationships between anterior capsule cover and IOL optic. Methods This is a prospective randomized masked study of 150 eyes undergoing phacoemulsification. Eyes received either option: 360 o total capsule cover (group I); partial cover (group II); or no cover (group III). OS was calculated as difference in anterior chamber depth after administration of cyclopentolate 1% and pilocarpine 2% on IOLMaster s at separate visits at 6 months follow-up. Subsequently, using retro-illumination photographs, percentage area of capsule cover was calculated. OS within and between groups I and II was analyzed. The impact of one quartile change in area of capsule cover on percentage change in OS was measured for both groups. Unpaired t-test, correlation, and regression were applied. Results In groups I, II, and III, mean age of patients was 56.6876.38, 57.0977.34, 59.1576.35 years, respectively; mean OS (mm) was 1.2570.28, 1.2070.24; 0.9570.26 (P ¼ 0.013), respectively; and percentage area of capsule cover (%) was 47.35710.48, 33.83710.11, 0.1670.13 (P ¼ 0.001), respectively. Mean percentage area of capsule cover in group I vs group II was significant (P ¼ 0.001). OS was 1.2270.26 mm in groups I and II (combined) vs 0.9570.26 mm in group III (P ¼ 0.004, (0.06, 0.33)). OS in group I vs group II was not significant (P ¼ 0.46). Correlation coefficient was r ¼ 0.38 (Po0.001). With every increment on quartile (a quartile is any of the three values which divide the sorted data set into four equal parts, so that each part represents one-fourth of the sample or population) class of area of capsule cover the OS increased by 0.12 mm. ConclusionThe OS differed significantly between total and partial cover groups combined vs no cover group.

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In vivo Observation of the Axial Movement of Intraocular Lenses through an Anterior Eye Segment Analysis System

Cited by 8 publications

References 2 publications

Magnetic resonance imaging of aging, accommodating, phakic, and pseudophakic ciliary muscle diameters

Magnetic resonance imaging of aging, accommodating, phakic, and pseudophakic ciliary muscle diameters

Optimum target refraction for highly and moderately myopic patients after monofocal intraocular lens implantation

Anterior capsule cover and axial movement of intraocular lens

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