睫状肌收缩与可折叠人工晶状体植入眼伪调节力的关系

目的分析和探讨可折叠人工晶状体（IOL）植入眼睫状肌收缩功能与伪调节力的关系。方法超声乳化白内障吸除及囊袋内可折叠IOL植入术后3个月,采用红外验光仪中调节性微波动分析软件检测瞳孔直径2．0—3．5mm、对光反应良好的50例患者（50只眼）的睫状肌调节性微波动高频成分（HFC）,并与患者术眼的伪调节力、IOL移动度等因素进行相关分析。结果HFC与IOL移动度呈正相关（r=0．702,P〈0．01）,IOL移动度与伪调节力呈正相关（r=0．861,P〈0．01）,HFC与伪调节力呈正相关（r=0．915,P〈0．01）。即IOL植入术后睫状肌的收缩能力越强,则IOL移动度越大,术后伪调节力越强。结论可折叠IOL植入术后术眼的睫状肌收缩可能导致IOL移动,这可能是IOL眼伪调节力增大的重要原因之一。     

Age-related changes in human ciliary muscle and lens: a magnetic resonance imaging study

PURPOSE: To use high-resolution magnetic resonance (MR) images of the eye to directly measure the relationship between ciliary muscle contraction and lens response with advancing age. METHODS: A General Electric, 1.5-Tesla MR imager and a custom-designed eye imaging coil were used to collect high-resolution MR images from 25 subjects, 22 through 83 years of age. A nonmagnetic binocular stimulus apparatus was used to induce both relaxed accommodation (0.1 diopter [D]) and strong accommodative effort (8.0 D). Measurements of the ciliary muscle ring diameter (based on the inner apex), lens equatorial diameter, and lens thickness were derived from the MR images. RESULTS: Muscle contraction is present in all subjects and reduces only slightly with advancing age. A decrease in the diameter of the unaccommodated ciliary muscle ring was highly correlated with advancing age. Lens equatorial diameter does not correlate with age for either accommodative state. Although unaccommodated lens thickness (i.e., lens minor axis length) increases with age, the thickness of the lens under accommodative effort is only modestly age-dependent. CONCLUSIONS: Ciliary muscle contractile activity remains active in all subjects. A decrease in the unaccommodated ciliary muscle diameter, along with the previously noted increase in lens thickness (the "lens paradox"), demonstrates the greatest correlation with advancing age. These results support the theory that presbyopia is actually the loss in ability to disaccommodate due to increases in lens thickness, the inward movement of the ciliary ring, or both.     

A comparison of accommodation amplitudes in pseudophakic eyes measured with three different methods

PURPOSE: To compare the accommodative amplitudes with three different methods in pseudophakic eyes with different types of intraocular lenses (IOLs). METHODS: Fifty-one pseudophakic eyes of 44 patients (age: 72.02+/-8.53 years) were studied. One of two different types of IOL were implanted (N=30, three-piece Alcon Acrysof MA60AC and N=21, one-piece Alcon Acrysof SA60AT) in-the-bag after standard phacoemulsification. The time of the examinations was 13.85+/-7.35 months postoperatively. We measured the amplitude of accommodation with three different methods: (1) subjective minus-lenses-to-blur method; (2) a new optical device (ACMaster, Carl Zeiss, Jena, Germany) using partial coherence interference (PCI) technique under physiological stimulus; and (3) objective anterior chamber depth measuring with a standard A-scan ultrasonic device (Ultrascan Imaging System, Alcon Laboratories, Forth Worth, TX, USA) before and after pharmacological relaxation of ciliary muscle. RESULTS: We measured -0.83+/-0.63 D amplitude of accommodation with subjective minus-lenses-to-blur method. The IOL position did not change significantly during physiological accommodation effort measured with PCI method (-0.026+/-0.134 mm). The change in the IOLs position between near fixating and after ciliary muscle relaxation was -0.18+/-0.28 mm measured with ultrasound. There were no significant differences between values of one-piece and three-piece IOL groups. CONCLUSION: The amplitude of accommodation measured by subjective and objective methods are different and are not comparable with each other. We did not observe any difference between values of examined two types of IOLs.     

The zonula, lens, and circumlental space in the normal iridectomized rhesus monkey eye

PURPOSE: To document zonular orientation and suspension of the lens during accommodation, and age-related changes of the circumlental space (CLS) at rest and during accommodation, in living iridectomized rhesus monkey eyes. METHODS: The CLS was measured in 34 iridectomized eyes of 24 living rhesus monkeys, age 5.7 to 26 years, in the resting and accommodated state, and the orientation of the zonula and suspension of the lens during accommodation was assessed qualitatively. RESULTS: The nonaccommodated CLS decreased significantly with age in both the nasal and temporal quadrants and tended to do so at a slightly faster rate in the temporal quadrant. The CLS correlated significantly with the accommodative amplitude: the greater the CLS the greater the accommodative amplitude. Multiple regression analysis indicated that age and CLS together are better predictors of accommodative amplitude than is age alone. The zonula appeared taut in the nonaccommodated eye throughout the age range despite the age-related decline in CLS. CONCLUSIONS: Characterization of age-related changes in the accommodative apparatus may help to model the system for hypothesis testing. The CLS may be an indicator of presbyopia-related processes in surrounding tissues. However, these results do not prove that the width of the CLS, in and of itself, has a causal relationship with accommodative amplitude, or that changes in the CLS play a pathophysiological role in presbyopia.     

Accommodative ciliary body and lens function in rhesus monkeys, I: normal lens, zonule and ciliary process configuration in the iridectomized eye

PURPOSE: The underlying causes of presbyopia, and the functional relationship between the ciliary muscle and lens during aging are unclear. In the current study, these relationships were studied in rhesus monkeys, whose accommodative apparatus and age-related loss of accommodation are similar to those in humans. METHODS: Centripetal ciliary body and lens equator movements were measured during accommodation in 28 eyes of 21 rhesus monkeys (ages, 5.7-26 years) by goniovideography. Ultrasound biomicroscopy was performed in 21 eyes of 17 monkeys. Narrowing of the angle between the anterior aspect of the ciliary body and the inner aspect of the cornea was used as a surrogate indicator of forward ciliary body movement during accommodation. RESULTS: Average centripetal ciliary body movement in older eyes (age > or =17 years, n = 16) was approximately 20% (0.09 mm) less than in young eyes (age, 6-10 years, n = 6), but not enough to explain the 60% (0.21 mm) loss in centripetal lens movement nor the 76% (10.2 D) loss in accommodative amplitude. Average forward ciliary body movement was 67% (49 degrees ) less in older (n = 11) versus young (n = 6) eyes. Maximum accommodative amplitude correlated significantly with the amplitude of centripetal lens movement (0.02 +/- 0.003 mm/D; n = 28; P < 0.001) and with forward ciliary body movement (3.34 +/- 0.54 deg/D; n = 21; P = 0.01). CONCLUSIONS: Decreased lens movement with age could be in part secondary to extralenticular age-related changes, such as loss of ciliary body forward movement. Ciliary body centripetal movement may not be the limiting component in accommodation in the older eye.     

Refractive lens exchange versus iris-claw Artisan phakic intraocular lens for hyperopia

PURPOSE: To study a paired-match comparison between refractive lens exchange with pseudophakic IOL implant (RLE) and Artisan phakic IOL for high hyperopia. METHODS: Nineteen eyes (12 patients, 20 to 41 years old) with an Artisan phakic IOL (Model 203: 1.00-D increment) for hyperopia from +2.75 to +9.25 D were matched to 19 eyes (15 patients, 26 to 46 yr) with hyperopia from +2.75 to +7.50 D, who had refractive lens exchange (pseudophakic IOL implantation; lenses: 0.50-D increment). Average paired-match difference was 1.13 D and 7.7 years of age. RESULTS: At 1 month after surgery, 84% of refractive lens exchange/pseudophakic IOL eyes and 94% of Artisan phakic IOL eyes had a spherical equivalent refraction within +/- 1.00 D of emmetropia; 58% and 68% of eyes, respectively, were within +/- 0.50 D (P = .97). No eye lost lines of best spectacle-corrected visual acuity (BSCVA) and no significant changes in BSCVA were found in any eye at 1 month after surgery (P = .17). The percentage of eyes with uncorrected visual acuity (UCVA) of 20/40 or better improved from 79% to 89% of eyes at 1 to 2 months after phakic IOL; it remained at 89% to 82% of eyes from 1 to 2 months after refractive lens exchange/ pseudophakic IOL. The coefficient of correlation showed statistically better accuracy (intended vs. achieved refraction; P = .035) for the Artisan phakic IOL (R = 0.83) than for refractive lens exchange/ pseudophakic IOL (R = 0.50). CONCLUSIONS: Spherical equivalent refraction outcome and BSCVA after surgery were similar for both procedures. The Artisan phakic IOL in carefully selected patients provided a better overall outcome for young patients with high hyperopia whose accommodation was preserved, as compared to refractive lens exchange.     

Deterioration of amplitude of the accommodation with age and its possible restoration in the intraocular lens implanted eye]

This study aimed to determine whether pseudophakia which have deteriorated amplitude of accommodation with age, i.e., presbyopia and which received implantation of refractively changeable intraocular lenses after cataract extraction are able to regain accommodative function. According surveys on aging in the literature, functional deterioration of the ciliary muscle and the zonular fiber is not so striking compared to the changes of crystalline lens material and capsule. Consequently the artificially pseudophakic eye can be expected to regain accommodative function when the crystalline lens material could be replaced by an appropriately visco-elastic material before 80 years of age when the crystalline lens capsule still retain its elasticity.     

Apparent accommodation of the aphakic eye corrected by an artificial lens

We measured apparent accommodation in 51 pseudophakic eyes (44 patients, after implantation of anterior (15 eyes) or posterior (36 eyes) intraocular lens. Glasses for distant vision were born during the test. The mean apparent accommodation was 1.89 +/- 0.91 dpt. 25 among these 51 pseudophakic eyes who were tested without their glasses showed a mean apparent accommodation that was not different in statistical and clinical terms. The mean accommodative power of 25 phakic and presbyopic eyes used as controls was 1.31 +/- 1.01 dpt. For these 51 pseudophakic eyes the correlation between apparent accommodation and the reciprocal of the pupillary diameter is the most significant (r = 0.79): the smaller the pupil, the greater the apparent accommodation. There was a negative correlation between apparent accommodation and anterior chamber depth (r = -0.64). No correlation was found between pseudo-accommodation and corrected visual acuity, corneal astigmatism and refractive error.     

Intact accommodation in pseudophakic eyes

BACKGROUND: The purpose of the cataract surgery should be to guarantee the physiology of a young eye, especially with the ability to accommodate. This study focuses on accommodative changes in pseudophakic eyes. MATERIALS AND METHODS: Using the IOL Master (Carl Zeiss Jena), Scheimpflug camera EAS 1000 (Nidek) and Pupillograph (AMTech GmbH), detailed measurements of pseudophakic eyes for near and distance fixation were taken. The average age of all patients is 71 years. RESULTS: With regard to the pseudophakic pupil movement a statistically significant decrease of the pupil size, for the light-influenced, and for the light-constricted pupil in near fixation could be shown. Furthermore, a statistically significant decrease of the pupil-constricting amplitude and a decrease of the reaction time after a light impulse was shown. Central vertical and horizontal corneal radii show significant increases with accommodation, which results in a decrease of the central corneal curvature. While reducing the anterior chamber depth, the pseudophakic eyes show a statistically significant minimising of the superior anterior chamber angle. CONCLUSION: Pseudophakic accommodating eyes react similarly compared to the phakic accommodating eyes of young individuals.     

Age-related changes in static accommodation and accommodative miosis

An attempt was made to explore the validity of the Hess-Gullstrand and Duane-Fincham models of presbyopia development, on the assumption that accommodative miosis could be used as an indicator of ciliary muscle effort. Monocular accommodation response and pupil size were measured as a function of accommodation demand over the range 0-4 D, in 48 normal subjects with ages between 17 and 56 years. The slope of the response/stimulus curve was found to decrease only slowly with age up to about 35 years and then to decline more rapidly. Accommodative miosis per dioptre of accommodation response did not change systematically with age up to about 35 years, this being apparently more in accord with the Hess-Gullstrand model. However, accommodative miosis varied very widely between younger subjects of similar age and accommodative amplitude (from zero to around 1 mm per dioptre of accommodation response for subjects in their twenties). It is concluded that miosis does not necessarily accompany accommodation and that its magnitude is not related in any simple general way to ciliary muscle contraction. Hence it cannot be used to support or refute particular theories of presbyopia.     

Comparison of pilocarpine-induced and stimulus-driven accommodation in phakic eyes

With the recent introduction of potentially accommodative intraocular lenses (IOL), there is a need for methods to evaluate their accommodative potential. In most studies assessing IOL movement, pilocarpine is used to stimulate contraction of the ciliary muscle. The aim of this study is to determine if pilocarpine-induced ciliary muscle contraction is comparable to physiological stimulus-driven accommodation in young and presbyopic subjects. Ten emmetropic young subjects (23-25 years) and 11 emmetropic presbyopic subjects (51-62 years) were included in this study. Anterior chamber depth (ACD) and lens thickness (LT) were assessed with partial coherence interferometry (PCI). A moveable stimulus was coupled to the PCI equipment for measurement of biometric lens changes. ACD was measured with the stimulus at infinity and then at the subjects individual nearpoint, and after application of two drops of 2% pilocarpine. In young subjects, there was no significant difference in lens change between nearpoint and pilocarpine stimulation. Presbyopic subjects showed no relevant lens change when accommodating at the nearpoint, however, under pharmacologically induced ciliary muscle contraction with pilocarpine, there was a significant forward shift of the anterior and posterior lens pole, leading to a translational forward lens shift of about 150 microm. This study demonstrates that pilocarpine acts "physiologically" in young phakic subjects, but is a "superstimulus" in presbyopic phakic subjects. Therefore, IOL movement may be overestimated when using pilocarpine to stimulate accommodation.     

Apparent accommodation in pseudophakic eyes as measured with visually evoked potentials.

We measured apparent accommodation with pattern reversal visually evoked cortical potentials in 27 pseudophakic eyes after the implantation of posterior chamber intraocular lenses. The patients ranged in age from 47-83 years. The amplitude of accommodation was not significantly different between pseudophakic eyes and normal phakic eyes. Apparent accommodation was inversely proportional to the pupillary diameter and was significantly correlated with corneal astigmatism. No significant relationship was noted between apparent accommodation and age of patients, corrected visual acuity, or refractive error.     

老视理论及治疗进展

老视是一种常见的眼部退行性病变,表现为年龄相关性调节力下降,它影响到每一个老年人。随着全新的Schachar调节理论的提出以及传统理论的发展,近年来出现了多种老视治疗方法。目前除了通过各种框架眼镜和接角镜来矫正老视,还可以应用手术方法如前睫状区巩膜切开样(AGS)以及巩膜扩张(SRP)来恢复调节能力。采用人工晶状体植入形成单眼视,多焦点人工晶状体,可调节型人工晶状体,LASIK手术也都是可行的老视治疗措施。本文总结了目前有关老视的各种机制和治疗方法。     

Dynamic aberrometry during accommodation of phakic eyes and eyes with potentially accommodative intraocular lenses

Since the introduction of potentially accommodative intraocular lenses (IOLs), it was hard to perform an objective evaluation of the accommodative amplitude in pseudophakic eyes. Laser interferometric measurements were performed to evaluate anterior chamber depth changes, which provides information on the functionality of potentially accommodative IOLs. By means of wavefront analysis, the dynamic behaviour of potentially accommodative IOLs can be determined. All measurements in this study were performed using a Hartmann-Shack aberrometer at a frequency of 7 Hz. Six to 8 weeks after implantation of potentially accommodative IOLs (CrystaLens AT-45, C&C Vision, 1CU, Humanoptics), 43 eyes were investigated using this dynamic wavefront analysis. Patients focussed at a distance target for 10 s, followed by focussing at a near target for 10 s and then again at a distance target for a further 10 s. During these 30 s, a total of 200 single measurements were performed. The same measurements were also conducted in healthy eyes of young persons as well as in eyes after implantation of standard IOLs for comparative purposes. The dynamic course of changes in low-order aberrations (defocus, astigmatism) as well as high-order (e.g., fourth-order spherical aberration) were analysed. Dynamic wavefront analysis allowed objective and observer-independent measurement of changes in accommodation in phakic and pseudophakic eyes. Dynamic aberrometry is capable of objectively quantifying the effect of any surgical option for the treatment of presbyopia. We recommend use of this technology in addition to the common psychophysical examinations to attain objective information on the efficacy of the treatment modality used.     

老視理論及治療進展

老視是一種常見的眼部退行性病燮,表現為年齡相關性調節力下降,它影響到每一個老年人.隨着全新的Schachar調節理論的提出以及傳統理論的發展,近年來出現了多種老視治瘵方法.目前除了通過各種框架眼鏡和接觸鏡來矯正老視,還可以應用手術方法如前睫狀區鞏膜切開術(ACS)以及鞏膜擴張(SRP)來恢復調節能力.采用人工晶狀體植入形成單眼視,多焦黠人工晶狀體,可調節型人工晶狀體,LASIK手術也都是可行的老視治瘵措施.本文總結了目前有關老視的各種機制和治瘵方法.     

Subjective measurement of apparent accommodation in pseudophakic eyes with pattern VECPs

Apparent accommodation was measured subjectively with pattern reversal visually evoked cortical potentials (PVECPs) in 22 pseudophakic eyes (20 patients, 47-83 years of age) after implantation of posterior chamber intraocular lenses. No significant difference was found in the obtained amplitude of accommodation measured with PVECPs between pseudophakic eyes and normal phakic eyes. Moreover this amplitude was independent from the age of patients, corrected visual acuity, or refractive errors. In one case, however, the amplitude of apparent accommodation was reduced with artificial dilating of the pupil diameter and contribution of the depth of focus to the apparent accommodation was indicated.     

Akreos MI60型人工晶状体眼伪调节的研究

目的:研究1.8mm微切口超声乳化白内障摘除术植入博士伦四点支撑板状襻Akreos MI60人工晶状体眼的伪调节力。方法:回顾性系列病例研究。选取我院单纯年龄相关性白内障行1.8mm微切口超声乳化联合博士伦Akreos MI60人工晶状体植入术的患者19例22眼,在术后6mo进行随访,观察其远视力、最佳矫正远视力,35cm近视力、最佳矫正近视力;离焦法测定人工晶状体眼伪调节力(主观法);在药物(20g/L毛果芸香碱)诱导下用UBM测量前房深度的变化并计算其伪调节力(客观法)。结果:术后6mo,裸眼远视力为0.81±0.11,最佳矫正远视力为0.91±0.09;35cm近视力为0.62±0.10,最佳矫正近视力为0.85±0.11;调节幅度离焦法测定人工晶状体眼伪调节力为2.55±0.24D,前房深度测量法(ACD法)为0.72±0.13D。结论:对于没有明显屈光不正的患者,博士伦AkreosMI60人工晶状体眼术后早期具有一定的伪调节力,主观法测得调节幅度大于客观法。     

Accommodation and presbyopia

The mechanism of accommodation has been studied for at least four hundred years. The most interesting aspect of accommodation is that its time course is well in advance of other physiological functions – it begins to decline by adolescence and is lost about two-thirds of the way through the normal line span. The state of presbyopia is reached when accommodation has declined sufficiently to interfere with close tasks requiring acute vision. Presbyopia is generally considered to originate with the 'plant' of the accommodative system, either within the lens and its capsule or within their support structures. One of the lenticular theories, the Hess–Gullstrand theory, is distinguished from other theories by its claim that as age increases there is an increasing excess amount of ciliary muscle contraction beyond the ability of the lens and capsule to respond to it. For all other theories, the maximum possible amount of ciliary muscle contraction is always necessary to produce maximum accommodation, at least beyond the age at which it reaches its peak. From my review of the present understanding of the mechanisms of accommodation and the theories of the development of presbyopia, I conclude that there is overwhelming evidence against the Hess–Gullstrand theory and that it is unlikely that changes in the ciliary muscle contractility contribute significantly to the development of presbyopia.     

Intraocular lens movement caused by ciliary muscle contraction

PURPOSE: To investigate intraocular lens (IOL) movement, measured as a change in anterior chamber depth (ACD) caused by pilocarpine-induced ciliary muscle contraction. SETTING: Department of Ophthalmology, University of Vienna, Vienna, Austria. METHODS: In this prospective study, the ACD was measured using high-precision, high-resolution, dual-beam partial coherence interferometry in 62 pseudophakic eyes of 55 patients under pilocarpine- and cyclopentolate-induced ciliary muscle contraction and relaxation. The following were studied: 2 models of a ring-haptic IOL (designed to accommodate), a plate-haptic IOL, and 3 types of 3-piece IOLs. Measurements were performed 3 months after surgery. RESULTS: The ring-haptic IOLs and plate-haptic IOL showed a forward movement (ring haptic 43A, -116 microm; ring haptic 43E, -222 microm; plate haptic -162 microm). The 3-piece IOLs showed no change in ACD except in 1 IOL type in which there was backward movement (156 microm). CONCLUSIONS: Pilocarpine-induced ciliary muscle contraction caused forward movement of ring- and plate-haptic IOLs that resulted in an estimated accommodative amplitude of less than 0.50 diopter in most cases. The accommodating ring-haptic IOLs did not perform better than the conventional plate-haptic IOL.     

虹膜固定型有晶状体眼人工晶状体植入对高度近视患者睫状肌调节性微波动及调节力的影响

目的通过测量睫状肌调节性微波动高频成分(high frequency component,HFC)来分析有晶状体眼人工晶状体(phakic intraocular lens,P-IOL)植入对高度近视患者睫状肌收缩能力及调节力的影响。方法收集2004年12月～2006年3月在我院进行虹膜固定型有晶状体眼人工晶状体Verisyse植入的患者54例(54眼)。采用NIDEK ARK-730A红外验光仪中调节性微波动分析软件,分别在术后1周、3个月对该54例患者(54眼)进行睫状肌调节性微波动高频成分检查。并与患者术后调节力进行相关性分析。结果HFC与Verisys植入术后1周及3个月的调节力均正相关(术后1周r=0.628,P<0.01;术后3个月r=0.835,P<0.01);Verisyse植入术后3个月的HFC及调节力均较术后1周的HFC及调节力有明显提高。结论高度近视患者有晶状体眼人工晶状体植入有利于术后睫状肌收缩能力及调节力的提高。