Anterior chamber optical coherence tomography study of human natural accommodation in a 19-year-old albino

Baikoff, G; Lutun, E.; Wei, Jay; Ferraz, C.

doi:10.1016/j.jcrs.2003.12.043

Cited by 55 publications

(48 citation statements)

References 14 publications

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“…While studying accommodation in an albino patient, 9 we found that the ciliary sulcus' horizontal diameter decreased by about 900 mm for 10 diopters of accommodation. In a study of 20 cadaver eyes using ultrasound biomicroscopy, Werner et al demonstrated that the sulcus' vertical diameter was larger than the horizontal diameter in the same way that the anterior chamber's vertical internal diameter is larger than the horizontal diameter (L. In ultrasound studies, Garcia-Feijoó et al 22,23 demonstrate that posterior chamber IOLs were rarely in the sulcus and often rested against the zonules, crystalline lens, or the ciliary body.…”

Section: Role Of the Anterior Chamber Oct In Evaluating Posterior Chamentioning

confidence: 84%

“…It is now being used to analyze the anterior segment. [5][6][7][8] Over the past 3 years, [9][10][11][12][13][14] I have routinely used 3 versions of an anterior segment optical coherence tomographer and would like to share my experience and describe the criteria for selecting pIOLs that I have defined.…”

Section: J Cataract Refract Surg 2006; 32:1827-1835 Q 2006 Ascrs and mentioning

confidence: 99%

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Anterior segment OCT and phakic intraocular lenses: A perspective

Baikoff¹

2006

Journal of Cataract and Refractive Surgery

118

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Perfect tolerance is expected when one implants a phakic intraocular lens (pIOL) in the anterior segment. Not only should the material be compatible, but the pIOL must respect the anatomy of the anterior chamber. Based on 3 years of experience using an anterior segment optical coherence tomographer (Visante OCT, Carl Zeiss Meditec), I have defined numerous safety criteria for pIOLs. The internal dimensions of the anterior chamber must be considered along different meridians. I propose an objective measurement of the iris dome, the crystalline lens rise (CLR), which is the distance between the anterior pole of the crystalline lens and a line joining the 2 opposite iridocorneal angles. In a series with the Artisan IOL (Ophtec), pigment dispersion syndrome appeared in 70% of cases in which the CLR was greater than 600 microm. Angle-supported IOLs must be placed relative to the anterior chamber's largest diameter; in the same series of cases, the anterior chamber was oval with a large vertical axis in 74% of cases. The posterior face of an angle-supported IOL must have a 700 microm vault to respect the physiological modifications of the crystalline lens. It is difficult to know the posterior chamber's exact diameter as it varies with the horizontal or vertical axis. It also undergoes constant modifications due to accommodation and aging.

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Section: Role Of the Anterior Chamber Oct In Evaluating Posterior Chamentioning

confidence: 84%

Section: J Cataract Refract Surg 2006; 32:1827-1835 Q 2006 Ascrs and mentioning

confidence: 99%

Anterior segment OCT and phakic intraocular lenses: A perspective

Baikoff¹

2006

Journal of Cataract and Refractive Surgery

118

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“…41 With accommodation, the rhesus ciliary muscle moves anteriorly as well as inwardly with accommodation 33 ; conversely, the human ciliary muscle only moves inwardly with accommodation. 42 Finally, microscopy studies indicate that the aging human ciliary muscle develops more connective tissue, and in different regions, than in the rhesus monkey. 40,41 Given these species differences in the aging ciliary muscle location and function, presbyopia correction strategies that work in the rhesus model may not be effective in humans.…”

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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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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“…During examination, a subject fixates on an optical target whose focus can be adjusted to compensate for the subject's spherical ametropia, and images of the unaccommodated eye can be acquired. 17,18 Therefore, we used the AS-OCT to find out the changes of anterior segment morphology after LPI in PAC eyes.…”

Section: Introductionmentioning

confidence: 99%

Morphological changes of the anterior segment after laser peripheral iridotomy in primary angle closure

Lei

Wang

et al. 2007

Eye

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Purpose To study changes in anterior segment morphology after laser peripheral iridotomy (LPI) in primary angle closure (PAC) using anterior segment optical coherence tomography (AS-OCT).Methods LPI was performed on 15 consecutive primary angle closure patients (15 eyes). AS-OCT was used to record the morphology of the anterior segment before and after LPI. The central anterior chamber (AC) depth, the diameter of the pupil, the lens thickness, and the AC volume were measured. The peripheral AC depth and the configuration of iris were also observed qualitatively. The intraocular pressure (IOP) was measured by Goldmann applanation tonometer. Results The mean central AC depth was 1.939±0.228 and 1.970±0.235 mm before and after LPI, respectively, increasing by 1.6%, P ¼ 0.001. In all eyes but two, the central AC depth increased. The AC volume changed significantly after LPI (73.86 ± 14.58 vs 84.14±17.45 ll, Po0.001) and it increased in all eyes. The iris flattened and the peripheral AC deepened after LPI in all 15 eyes. The mean IOP was 17.8±3.3 and 15.9±3.1 mmHg before and after LPI, respectively, P ¼ 0.042. The changes of pupil diameter and lens thickness were not statistically significant. Conclusions LPI leads not only to the increase of peripheral anterior chamber depth and anterior chamber volume but also to an increase of central anterior chamber depth in eyes with primary angle closure.

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Anterior chamber optical coherence tomography study of human natural accommodation in a 19-year-old albino

Cited by 55 publications

References 14 publications

Anterior segment OCT and phakic intraocular lenses: A perspective

Anterior segment OCT and phakic intraocular lenses: A perspective

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

Morphological changes of the anterior segment after laser peripheral iridotomy in primary angle closure

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