Measurement of accommodation after implantation of an accommodating posterior chamber intraocular lens

PURPOSE: To analyze techniques of measuring accommodation after implantation of an accommodating posterior chamber intraocular lens (PC IOL). SETTING: Department of Ophthalmology and University Eye Hospital, University Erlangen-Nürnberg, Erlangen, Germany. METHODS: This prospective study analyzed 23 eyes of 23 patients (aged 41 to 87 years) after cataract surgery and PC IOL implantation (1 CU, HumanOptics) 4 weeks and 3 and 6 months after surgery. The results were compared to those in an age-matched control group (n = 20) 6 months after surgery. The following methods were used to measure accommodation: dynamic with objective techniques (PlusOptix PowerRefractor videorefractometry, streak retinoscopy) and subjective techniques (subjective near point [push-up test, accommodometer], defocusing); static with pharmacologic stimulation after pilocarpine 2% eyedrops directly (conventional refractometry); indirectly (change in the anterior chamber depth [ACD] with Zeiss IOLMaster). RESULTS: Results at 6 months, given as mean +/- SD (range), in the study and control groups, respectively, were as follows: near visual acuity (Birkh?user reading charts at 35 cm) with distance correction, 0.32 +/- 0.11 (0.20 to 0.60) and 0.14 +/- 0.10 (0.05 to 0.30); accommodation amplitude (diopters) by PowerRefractor, 1.00 +/- 0.44 (0.75 to 2.13) and 0.35 +/- 0.26 (0.10 to 0.65), by retinoscopy, 0.99 +/- 0.48 (0.13 to 2.00) and 0.24 +/- 0.21 (-0.13 to +0.75), by subjective near point, 1.60 +/- 0.55 (0.50 to 2.56) and 0.42 +/- 0.25 (0.00 to 0.75), and by defocusing, 1.46 +/- 0.53 (1.00 to -2.50) and 0.55 +/- 0.33 (0.25 to 0.87). The mean ACD decrease (mm) was 0.78 +/- 0.12 (0.49 to 1.91) and 0.16 +/- 0.09 (0.00 to 0.34) after pilocarpine 2% eyedrops, indicating a mean accommodation of 1.40 D and 0.29 D, respectively, based on Gullstrand's model eye (P =.001). The lowest fluctuation between follow-ups was with the subjective near point and the defocusing techniques followed by ACD decrease with the IOLMaster. CONCLUSIONS: Accommodation after implantation of an accommodating PC IOL should be assessed with several techniques, including subjective and objective, to differentiate true pseudophakic accommodation from pseudoaccommodation. Researchers should be aware of the different variability and consistency of measurements with each technique over time.     

Stability of refraction, accommodation, and lens position after implantation of the 1CU accommodating posterior chamber intraocular lens

PURPOSE: To investigate stability of refraction, anterior chamber depth (ACD), and accommodation up to 12 months after implantation of the 1CU accommodating posterior chamber intraocular lens (PC IOL). SETTING: Department of Ophthalmology, University Erlangen-Nürnberg, Erlangen, Germany. METHODS: In a prospective study, 15 eyes of 15 patients (mean age 62.2 years +/- 13.4 [SD] [range 44 to 86 years]) had phacoemulsification and PC IOL implantation. Distance refraction, accommodative range measured by the near point with an accommodometer, ACD measured with the IOLMaster (Carl Zeiss Meditec), and near visual acuity with best distance correction (Birkh?user charts at 35 cm) were determined after 3, 6, and 12 months and analyzed for signs of systematic changes. RESULTS: After 3, 6, and 12 months, the mean distance refraction was -0.28 +/- 0.54 diopters (D), -0.29 +/- 0.52 D, and -0.21 +/- 0.54 D, respectively; the mean accommodative range, 1.93 +/- 0.47 D, 1.85 +/- 0.62 D, and 2.02 +/- 0.38 D, respectively; the mean ACD without pharmacological induction of ciliary muscle contraction, 4.40 +/- 0.44 mm, 4.35 +/- 0.50 mm, 4.25 +/- 0.53 mm, respectively; and the mean near visual acuity with best distance correction, 0.41 +/- 0.15, 0.37 +/- 0.12, and 0.39 +/- 0.11, respectively. There were no statistically significant changes in any measurement during the follow-up (P>.1). CONCLUSIONS: Refraction, ACD, and accommodative range remained stable without indication of a systemic trend toward myopia, hyperopia, PC IOL dislocation, or regression of accommodative properties. The 1CU accommodating PC IOL provided stable refraction, accommodation, and PC IOL position for up to 1 year.     

Validity of anterior chamber depth measurements for the evaluation of accommodation after implantation of an accommodative Humanoptics 1CU intraocular lens

BACKGROUND: Changes in the anterior chamber depth (ACD) after pilocarpin application are generally regarded as reflecting an accommodative effect of accommodative intraocular lenses (IOLs) METHODS: We implanted Humanoptics 1CU accommodative IOLs into 25 eyes of 20 patients aged 53.2+/-14.7 years (range: 30-83 years). In seven of these patients, we were able to measure anterior chamber depth changes after the application of pilocarpine (2%) eye drops 3 months postoperatively using a Zeiss IOLMaster, an Orbscan II topography system, as well as by ultrasound biomicroscopy (20 MHz-US-head). RESULTS: Uncorrected near acuity was on average 0.4+/-0.23 (0.1-0.8) and uncorrected distance acuity was 0.76+/-0.23 (0.3-1). Before pilocarpine, ACD was 3.19+/-2.11 mm (IOL-Master), 3.35+/-2.22 mm (Orbscan II) and 3.35+/-2.21 mm (US-biomicroscopy) ( P=0.96). After pilocarpine, ACD was 2.61+/-1.71 mm (IOL-Master), 2.63+/-1.78 mm (Orbscan II) and 3.15+/-2.08 mm (US-biomicroscopy) ( P=0.002). The average individual ACD change before/after pilocarpine was 0.83+/-0.25 mm with the IOL-Master, 1.04+/-0.39 mm with the Orbscan II System and 0.28+/-0.14 with US-biomicroscopy ( P=0.0004). DISCUSSION: The 1CU Humanoptics accommodative IOL presented with potential accommodative capabilities in clinical evaluation. Drug induced accommodation by pilocarpine does not reflect real accommodative effects. The differences in ACD measurements between three different methods were statistically significant. Evaluation methods for accommodative IOLs should be carefully analysed and further development of objective means for evaluation is needed.     

Evaluierung der Wertigkeit objektiver und subjektiver Verfahren zur Messung von pseudophaker Akkommodation

Purpose

The aim of this study was to compare the validity and plausibility of various subjective and objective measurement methods for evaluation of pseudophakic accommodation.

Setting

Eye Clinic Bellevue, Kiel, Germany.

Methods

A total of 21 patients were examined over an average period of 34 months (range 12–51 months) after implantation of a potentially accommodative, model 1CU intraocular lens (IOL, HumanOptics, Germany). The following subjective measurements were taken: near point measurement with the accommodometer (Clement Clarke, Harlow, UK), defocus curve and near visual acuity with far and near reading charts. The IOLMaster (Carl Zeiss Meditec, Germany), ACMaster (Carl Zeiss Meditec, Germany) and Shin-Nippon K 5001 AR (Shin-Nippon, Japan) were employed as objective measurement devices. With this devices information is obtained about the anterior chamber depth (ACD, preoperative and postoperative), the movement of the IOL and the refractive change of eyes during the accommodative process.

Results

Depending on the method utilized there were large variations of the examined IOL in relation to the extent of the measured accommodative effects in their entirety with the objective as well as the subjective measurement method.

Conclusions

A differentiation of pseudophakic accommodation and pseudophakic pseudoaccommodation is not possible with the conventional measurement methods applied and examined in this study. Only the ACMaster is an objective method for measurement of the axial shift of an IOL. However, subjective measurement methods can only record the total of both accommodation portions but do not allow any scientifically-founded statement about the functional principle of a potentially accommodative IOL.     

Comparison of anterior chamber depth measurement methods in phakic and pseudophakic eyes

PURPOSE: To compare anterior chamber depth (ACD) measurements in phakic and pseudophakic eyes using a slit-beam photographic technique (IOLMaster, Carl Zeiss Meditec AG) with those obtained with the laboratory prototype version of partial coherence interferometry (PCI) and with conventional applanation ultrasound in phakic eyes. SETTING: Department of Ophthalmology, Vienna General Hospital, Vienna University, Vienna, Austria. METHODS: Thirty-three ACDs of 28 patients with age-related cataract were measured preoperatively with a slit-beam photographic technique (IOLMaster) and the prototype version of PCI. In 24 eyes, the ACD was also assessed with applanation ultrasound. In addition, 34 ACDs of 18 pseudophakic patients in a different study population were examined postoperatively with the IOLMaster and PCI. RESULTS: The median ACD in the phakic eyes was 3.06 mm (range 1.93 to 3.90 mm) with the IOLMaster, 3.09 mm with PCI (range 1.49 to 4.06 mm), and 2.87 mm (range 2.18 to 3.33 mm) with applanation ultrasound. The precision was 0.005 mm for PCI and 0.015 mm for IOLMaster measurement. The median difference between the IOLMaster and PCI ACD biometry was 0.01 mm +/- 0.14 (SD) (range -0.44 to 0.17 mm) (P =.71). In pseudophakic eyes, the 2 methods showed a median difference of -0.22 mm (range -0.45 to 1.99 mm) (P >.1) and did not correlate (r = 0.21; P >.2). CONCLUSIONS: In phakic eyes, the difference between IOLMaster and PCI measurements was small and not statistically significant. In pseudophakic eyes, the difference was larger and the methods did not correlate.     

Akkommodationsfähigkeit unter Einbeziehung refraktiver, biometrischer und demographischer Parameter

PURPOSE: The aim of this study was to evaluate the accommodation ability in healthy phakic eyes in relation to refraction and biometric parameters in order to get comparable results for patients with the accommodative 1 CU posterior chamber lens. METHODS: The study included 120 normal eyes of 120 patients (77 males, 43 females, mean age: 40+/-18, range: 11-70 years). The inclusion criteria were spherical equivalent for distance refraction <2 D, astigmatism <1.5 D, and a best-corrected visual acuity > or =0.8. Exclusion criteria were diabetes, glaucoma, cataract, traumas, or previous surgery. Subjects were divided into six age groups at increments of 10 years. Each group consisted of 20 subjects. Measurements included subjective and objective refraction (D), the accommodation ability (D) assessed with an accommodometer, and biometric parameters using the IOLMaster. In addition, the relation of anterior chamber depth and length of the eye was calculated for analyzing the relationship of anterior eye segment and accommodation. RESULTS: The spherical equivalent for distance refraction was 0.04+/-0.6 D with a range of -1.5 to 2.0 D. There was no sex-related significant difference of accommodation range. The accommodation range (D) decreased significantly with increasing age (p<0.0001, r=-0.895). The highest decrease could be found between the ages of 30 and 50 years. In subsequent years, the decline in accommodation ability was comparatively less. In association with the anterior chamber depth and the relation of anterior chamber depth and length of the eye, the accommodation ability fell with increasing age (p<0.001). The length of the eye did not correlate with the accommodation ability (p=0.8). CONCLUSION: There is a strong relationship between accommodation ability and age. Accommodation ability decreases strongly from the 3rd to the 5th decade; after that the loss of accommodation ability is relatively lower. The increase in lens thickness during the life span can implicate a correlation between the change of anterior chamber depth in relation to the length of the eye and a decrease of accommodation ability. Our results confirm Duane's hypothesis of accommodation and age.     

Pseudophakic accommodation with translation lenses – dual optic vs mono optic

PURPOSE: To investigate the pseudophakic accommodation effect in dual and mono optic translation accommodative intraocular lenses (AIOL) using linear matrix methods in the paraxial space. METHODS: Dual (anterior optic of power +32 D linked to a compensatory posterior optic of negative power) and mono lens power was determined in the non-accommodated state using linear geometric optics based on the Gullstrand model eye. The position of the AIOL was calculated from a regression formula. Pseudophakic accommodation was assessed with three systems: (1) forward shift of the mono optic lens, (2) anterior translation of the anterior optic in the dual optic lens system with an unchanged position of the posterior minus lens and (3) symmetrical anterior and posterior translation of the anterior and posterior lens. The Gullstrand model eye was modified by changing the axial length (and proportionally changing the phakic anterior chamber depth) to investigate the accommodative effect in myopic and hyperopic eyes. RESULTS: The dual optic lens system (2) yields a nearly constant accommodation amplitude of 2.4-2.5 D mm(-1) movement over the total range of axial lengths. The mono optic lens (1) provides a higher accommodative effect only in extremely short eyes (high refractive power of the lens), whereas for normal eyes (1.4-1.5 D mm(-1) movement) and for long (myopic) eyes the accommodative effect is much less than the dual optic lens. The dual optic lens system under condition (3) yields less accommodation amplitude compared with the dual optic system under condition (2) over the total range of axial length but provides higher accommodation amplitude compared with the mono optic lens system (1) with axial lengths greater than 22.3 mm (lens power 25.5 D). In the accommodated state, with lens translation of 1 mm, the absolute value of the lateral magnification increases with the refractive power of the mono optic lens (1) and decreases in both dual optic lens systems (under conditions 2 and 3). CONCLUSIONS: A mathematical strategy is presented for calculation of the accommodative effect of mono-optic and dual optic AIOL. The dual optic lens yielded a nearly constant accommodation amplitude of about 2.4-2.5 D mm(-1) translation, whereas the mono optic lens yielded an accommodative response of <2 D mm(-1) translation in long myopic or normal eyes. Only in extremely short eyes is the accommodative amplitude of the mono-optic lens higher than the dual optic lens.     

Messung der Akkommodation mittels optischer Biometrie

BACKGROUND: Making accommodation possible for all age groups is a topic of great interest. We applied optical biometry in order to study the physiological mechanisms in detail. Longitudinal relations in the optical axis were measured during accommodation in volunteers of different ages and lens states. METHODS: A total of 60 subjects (children, adolescents, adults, and pseudophakes) were examined using the IOL Master. We measured anterior chamber depth (ACD), axial length (AL), and changes in these two measurements during accommodation. RESULTS: Near accommodation (NA) in adolescents caused the largest ACD decrease (0.14+/-0.03 mm). ACD decreased in adults during NA but not in pseudophakic patients of comparable age. AL increased during NA in all groups by 0.01+/-0.01 mm. CONCLUSIONS: ACD decreased with age. Using a physiological stimulus, no change in ACD was measured during NA in pseudophakic patients. The documented increase in AL needs to be evaluated further.     

Paediatric secondary intraocular lens estimation from the aphakic refraction alone: comparison with a standard biometric technique

AIM: To compare the following two methods of paediatric secondary posterior chamber intraocular lens (PCIOL) determination with the Holladay formula: (1) estimation from the aphakic refraction alone (using assumed keratometry (K) of 44 diopters); and (2) calculation based on preoperative measured biometry. METHODS: (1) Retrospective medical record review in a referral eye hospital of children with aphakia aged < or =12 years who underwent secondary PCIOL implantation with an Alcon MA60BM lens; (2) PCIOL determination for a plano refraction by the above two methods (estimation and calculation); and (3) prediction of pseudophakic refraction for the PCIOL actually implanted by the above two methods compared with the actual pseudophakic refraction. RESULTS: 50 eyes of 30 children with aphakia were studied. The estimated (mean, 95% confidence interval (CI)) secondary PCIOL values (25.81, +/-1.65 D) and the calculated secondary PCIOL values (26.35, +/-1.50 D) were not significantly different (mean absolute value of the difference 1.86 D, 95% CI +/-0.41 D) by the two-tailed paired t test at alpha = 0.05 (p = 0.11). For each eye, the pseudophakic refractions predicted by the two methods for the PCIOL that was actually implanted differed, both from each other and from the actual pseudophakic refraction (repeated-measures analysis of variance, p<0.001; Tukey test, p<0.01). CONCLUSIONS: The method of PCIOL estimation from the aphakic refraction alone provides values similar to those obtained by a standard technique and can be useful if biometry is unavailable. Targeting a pseudophakic refraction in paediatric aphakia is prone to error.     

Determination of pseudophakic accommodation with translation lenses using Purkinje image analysis

PURPOSE: To determine pseudophakic accommodation of an accommodating posterior chamber intraocular lens (translation lens) using Purkinje image analysis and linear matrix methods in the paraxial space. METHODS: A 2 x 2 system matrix was defined for each Purkinje image I to IV using refraction, translation and mirror matrices. Image size (m) and axial image position (z) was determined as an example for an off-axis object (a 0.2 m off-axis object located 0.5 m in front of the cornea.). First, our method was applied to the phakic relaxed (emmetropic) and accommodated (6.96 D) Le Grand eye. Secondly, for demonstration of the applicability of the calculation scheme to the pseudophakic eye, we provide a clinical example where we determine the accommodation amplitude of the translation lens (1 CU, HumanOptics, Erlangen, Germany) from photographed Purkinje images in the relaxed and accommodated state. From the biometric data: axial length 23.7 mm, corneal power 43.5, corneal thickness 550 microns, implanted intraocular lens (IOL) with a refractive power of 20.5 D (shape equi-biconvex, refractive index 1.46), and refractive indices of the cornea, aqueous and vitreous from the Le Grand model eye, we calculated the refractive state and the sizes of Purkinje images I and III initiated from two off-axis light sources. RESULTS: For the Le Grand model eye, Purkinje image II (z/m = 3.5850 mm/0.0064) is slightly smaller than and directly in front of image I (z/m = 3.8698 mm/0.0077). Purkinje image III (z/m = 10.6097 mm/0.0151) is nearly double the size of image I and during accommodation it moves from the vitreous into the crystalline lens. Purkinje IV (z/m = 4.3244 mm/-0.0059) is inverted, three quarters the size of image I, lies in the crystalline lens and moves slightly towards the retina. For the pseudophakic eye, pseudophakic accommodation of 1.10 D was calculated from the proportion of distances between both Purkinje images I and III in the relaxed (3.04) and accommodated (2.75) state, which is in contrast to the total subjective accommodation of 2.875 D evaluated with an accommodometer. CONCLUSIONS: We present a straightforward mathematical strategy for calculation of the Purkinje images I-IV. Results of our model calculation resemble the values provided by Le Grand. In addition, this approach yields a simple en bloc scheme for determination of pseudophakic accommodation in pseudophakic eyes with accommodative lenses (translation lenses) using Purkinje image photography.     

Implantation of a new accommodative posterior chamber intraocular lens

PURPOSE: A new, potentially accommodative posterior chamber lens (PCIOL) was designed based on principles elaborated by Hanna using finite element computer simulation methods. We report 3-month postoperative results in patients. METHODS: In a prospective study, 12 eyes of 12 patients (age 45 to 87 yr) underwent phacoemulsification for cataracts and PCIOL implantation. The PCIOL, 1 CU, has haptics designed for anterior optic movement following ciliary muscle contraction. Patients were examined postoperatively after 1 and 2 days, 1, 2 and 6 weeks, and 3 months, and results were compared with a control group of 12 eyes that received standard PMMA or acrylic PCIOLs. RESULTS: Surgery was uncomplicated and all PCIOLs were well-tolerated and stable with good centration in the capsular bag. The results were (mean +/- SD [range] and median; 1 CU versus control PCIOL): near visual acuity (Birkh?user reading chart at 35 cm) with best distance correction 0.34 +/- 0.17 (0.2 to 0.6), 0.3 (J10-J1, median J7) versus 0.15 +/- 0.07 (0.1 to 0.3), 0.15 (J16-J7, median J13), P=.001; subjective near point 59 +/- 10 cm (40 to 100 cm), 53.5 cm versus 93 +/- 20 cm (64 to 128 cm), 86 cm, P=.004; retinoscopic accommodative range 1.2 +/- 0.4 D (0.63 to 1.5 D), 1.2 D versus 0.2 +/- 0.19 D (-0.25 to 0.5 D), 0.25 D, P < .001; decrease of anterior chamber depth after 2% pilocarpine 0.63 +/- 0.16 mm (0.40 to 0.91 mm), 0.63 mm versus 0.15 +/- 0.05 mm (0.08 to 0.20 mm), 0.17 mm, P < .001. CONCLUSIONS: The new PCIOL appears to be safe at short to medium term. Our results indicate pseudophakic accommodation secondary to focus shift with this PCIOL. Additional larger and long-term studies are necessary for exact evaluation of safety and accommodative power of this new PCIOL.     

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.     

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。     

Ultrasound biomicroscopic changes during accommodation in eyes with accommodating intraocular lenses: pilot study and hypothesis for the mechanism of accommodation

PURPOSE: To document ciliary body constriction and movement with the Crystalens AT-45 intraocular lens (IOL) (eyeonics) using ultrasound biomicroscopy. SETTING: Eye Clinic, Department of Neurological and Visual Sciences, University of Verona, Verona, Italy. METHODS: Patients with no preexisting ocular conditions other than cataract who agreed to return for follow-up were considered. Twenty eyes of 14 patients with a best corrected visual acuity of 5/10 or worse and a refractive error (spherical equivalent) of +/-1.0 diopter (D) had implantation of a Crystalens AT-45 accommodating IOL. Six patients had bilateral implantation. Ultrasound biomicroscopy was performed postoperatively at 1 and 6 months. Before and during accommodation, the anterior chamber depth (ACD) was measured to assess the endothelium-IOL distance and measure the scleral-ciliary process angle to determine whether there was anterior rotation of the ciliary body. The uncorrected distance acuity, best corrected distance acuity, uncorrected near acuity, distance corrected near acuity, best corrected near acuity, and accommodative amplitude were determined. Analysis was done to determine whether there was a correlation between the accommodative amplitude and the percentage variation in the ACD and scleral-ciliary process angle. RESULTS: All surgical procedures were uneventful. The mean uncorrected distance acuity at 1 month was 0.8 +/- 0.14 (SD) and remained stable at 6 months. Three of 20 eyes (15%) and 8 of 20 eyes (40%) had a Jaeger acuity of J1 and J3, respectively, without additional power correction. During accommodation, the mean reduction in ACD was 0.32 +/- 0.16 mm at 1 month and 0.33 +/- 0.25 mm at 6 months. The mean narrowing of the scleral-ciliary process angle was 4.32 +/- 1.87 degrees at 1 month and 4.43 +/- 1.85 degrees at 6 months. There was a correlation between accommodative amplitude and a decrease in the ACD (r=0.404) and a decrease in scleral-ciliary process angle (r=0.773). CONCLUSIONS: Anterior displacement of the Crystalens IOL and corresponding anterior rotation of the ciliary body occurred during near vision. The IOL displacement and rotation were proportional to the accommodation capacity.     

Pentacam AXL和IOLMaster 500测量白内障术后人工晶状体眼生物参数的比较

目的 比较Pentacam AXL及IOLMaster 500测量白内障术后人工.晶状体(IOL)眼生物参数的差异。设计 前瞻性病例系列。研究对象 2021年10月北京同仁医院白内障术后IOL眼患者69例(69眼)。方法 对患眼先后应用Pentacam AXL及IOLMaster 500测量眼轴长度(AL)、角膜曲率(K1、K2及Km)、前房深度(ACD)及角膜横径(WTW),不同仪器测量结果 进行配对t检验及一致性检验,并应用MedCalc软件对两组数据进行Bland-Altman分析。主要指标 AL,K1、K2及Km,ACD及WTW值,组内相关系数(ICC)值,Bland-Altman图的95%一致性界限及95%一致性界限以外的点。结果 Pentacam AXL和IOLMaster 500测量69例(69眼)IOL眼的AL分别为(23.57±1.18)mm、(23.58±1.18)mm,K1分别为(43.57±2.02)D、(43.65±2.09)D(P均>0.05);而Pentacam AXL测得K2为(44.55±2.04)D,Km为(44.06±2.01)D,WTW为(...     

Anterior chamber depth measurements in phakic and pseudophakic eyes: Pentacam versus ultrasound device

PURPOSE: To compare anterior chamber depth (ACD) measurements with a new optical device with those taken with a standard ultrasound (US) device in emmetropic phakic and pseudophakic eyes. SETTING: Department of Ophthalmology, Medical Health and Science Center, University of Debrecen, Debrecen, Hungary. METHODS: Forty-two phakic and 42 pseudophakic patients with normal axial lengths (mean 22.91 mm +/- 1.21 [SD]) were enrolled in the study. The ACD was measured 3 times with Scheimpflug-based Pentacam (Oculus) and then 3 times with a standard A-scan US device (AL-2000, Tomey). The data were then analyzed. RESULTS: In the phakic group, the mean ACD was 2.87 +/- 0.4 mm with the Pentacam and 2.89 +/- 0.49 mm with ultrasound A-scan (US) (P = .84). In the pseudophakic group, the mean ACD was 3.41 +/- 0.28 mm and 3.97 +/- 0.45 mm, respectively (P < .001). The correlation between measurements was significant in both the phakic and pseudophakic groups (r = .547/P < .001 and r = .404/P = .01, respectively). CONCLUSIONS: In phakic eyes, ACD measured with the Pentacam and with US was the same. However, in pseudophakic eyes, the difference was significantly lower when the ACD was measured with the Pentacam. Therefore, in pseudophakic patients, further evaluation of ACD data with the Scheimpflug-based system is necessary.     

Variation and correlation of clinical tests of accommodative function in a sample of school-age children.

Accommodative facility, lag of accommodation, accommodative response, and relative accommodation were measured in 244 school-age (7.9 to 15.9 years of age) children. The tests studied included monocular estimate method (MEM) dynamic retinoscopy, Nott dynamic retinoscopy, low neutral dynamic retinoscopy, the binocular cross cylinder test, lens accommodative rock (facility), distance (near-far) accommodative rock, negative relative accommodation (NRA), and positive relative accommodation (PRA). The mean, standard deviation, and range of test findings of each test are presented. Coefficients of correlation among the various tests are presented.     

儿童和青少年近视调节功能的临床分析

目的 探讨发病早期的儿童和青少年近视的调节功能状态,分析主导眼和非主导眼的调节功能水平.方法 应用动态检影法和移近法分别测量50例发病1～2年的学龄期儿童和青少年近视患儿调节滞后和调节幅度;同样方法测量20例正视儿童和25例远视屈光不正患儿;检测其主导眼和非主导眼.结果 近视患儿的主导眼和非主导眼的调节幅度和调节滞后与正视儿童均差异无统计学意义;而其主导眼和非主导眼的调节幅度比远视患儿明显更大(t=2.21,P=0.03＜0.05;t=2.83,P=0.006＜0.05);两组的调节滞后差异无统计学意义.50例近视患儿主导眼和非主导眼的调节滞后值分别为(0.73±0.31)D和(0.81±0.38)D,主导眼和非主导眼间差异有统计学意义(t=2.14,P=0.038＜0.05);调节幅度分别为(13.39±3.51)D和(13.26±3.60)D,差异无统计学意义.95例观察对象(近视、正视和远视患儿)的主导眼的调节滞后度为(0.68±0.36)D,非主导眼调节滞后度为(0.75±0.34)D,主导眼和非主导眼间的差异有统计学意义(t=2.06,P=0.042＜0.05);主导眼调节幅度(12.9±3.09)D,非主导眼为(12.6±3.09)D,差异无统计学意义(t=1.49,P=0.14).结论 发病早期的儿童和青少年近视的调节滞后值和调节幅度与正视儿童无明显差别;调节幅度比远视儿童的更大.儿童和青少年主导眼的调节滞后比非主导眼的更小,进行调节滞后相关研究时应注意主导眼和非主导眼的区别.     

Simultaneous measurements of refraction and A-scan biometry during accommodation in humans.

PURPOSE: Accommodation is a dioptric change in power of the crystalline lens resulting from ciliary muscle contraction that leads to an increase in lens surface curvatures and thickness and changes in the position of lens surfaces. Previous studies have used A-scan ultrasound to measure changes in the position of lens surfaces with voluntary accommodation, but have not simultaneously measured the change in refraction. The goal of this study is to simultaneously measure and correlate refractive and biometric changes in the lens during voluntary accommodation in humans. METHODS: Refraction was measured off-axis in the right eye and biometry on-axis in the left eye simultaneously during voluntary accommodation in 22 human subjects between the ages of 21 and 30 years (mean +/- standard deviation: 25.8 +/- 2.3 years). Subjects viewed a distant target and four near targets spanning the full accommodative range available to evaluate refraction and lens surface position at each accommodative state. RESULTS: Maximum objectively measured accommodative amplitude of all subjects was 5.64 +/- 0.21 D (mean +/- standard error of mean). Biometric and refractive changes during accommodation were linearly correlated. The mean +/- standard error of mean decrease in anterior chamber depth was 0.051 +/- 0.008 mm/D, increase in lens thickness was 0.067 +/- 0.008 mm/D, and increase in anterior segment length was 0.017 +/- 0.005 mm/D during accommodation. There was a net anterior movement of the lens center of 0.017 +/- 0.005 mm/D. CONCLUSION: Anterior chamber depth, lens thickness, and anterior segment length change linearly with refraction during accommodation. Per-diopter changes in the lens were greater in the current study compared with previous studies in which only accommodative demand was measured, which overestimates the accommodative response.     

Comparison of anterior chamber depth measurements using Orbscan II and IOLMaster

PURPOSE: To evaluate and compare anterior chamber depth (ACD) measurements using Orbscan II (Bausch & Lomb, Rochester, NY) and IOLMaster (Carl Zeiss Meditec AG, Jena, Germany). METHODS: In this prospective clinical study, the authors measured ACD of 145 phakic eyes of 30 healthy volunteers and 115 patients using Orbscan II and IOLMaster. Average patient age was 52.9+/-19.4 (range 16 to 87) years. ACD was evaluated from corneal epithelium to anterior lens surface. Additionally, axial length (AL) was measured using the Zeiss IOLMaster to calculate the regression coefficient between AL and ACD. RESULTS: Mean ACD was 3.35+/-0.43 mm (range 2.01 mm to 4.37 mm) using Orbscan II and 3.36+/-0.41 mm (range 2.09 mm to 4.24 mm) using IOLMaster. Mean total axial length was 24.04 mm +/- 2.1 mm (range 20.7 mm to 31.41 mm). The linear regression coefficient of ACD between both methods was R=0.95. ACD and AL correlated only slightly (R=0.57). The Spearman coefficients of rank correlation were 0.94 and 0.61, respectively. A p value less than 0.01 (paired Wilcoxon test) was considered statistically significant. However, a significant difference was not calculated comparing ACD measurements using both systems and the Bland-Altman-Plot showed 95% of the differences ranging between 0.25 and -0.27 mm. CONCLUSIONS: Regarding clinical application, both systems seem to be equally good and interchangeable in clinical practice in terms of ACD evaluation.