Accommodation In Pseudophakic Eyes Research Articles

Axial elongation measured by long scan depth optical coherence tomography during pilocarpine-induced accommodation in intraocular lens-implanted eyes

We used an ultra-long scan depth optical coherence tomography (UL-OCT) system to investigate changes in axial biometry of pseudophakic eyes during pilocarpine- induced accommodation. The right eyes from 25 healthy subjects (age range 49 to 84 years) with an intraocular lens (IOL) were imaged twice in the non-accommodative and the accommodative states. A custom-built UL-OCT instrument imaged the whole eye. Then accommodation was induced by two drops of 0.5% pilocarpine hydrochloride separated by a 5-minute interval. Following the same protocol, images were acquired again 30 minutes after the first drop. The central corneal thickness (CCT), anterior chamber depth (ACD), IOL thickness (IOLT), and vitreous length (VL) were obtained using custom automated software. The axial length (AL) was calculated by summing the CCT, ACD, IOLT, and VL. With accommodation, ACD increased by +0.08 ± 0.09 mm, while the VL decreased by −0.04 ± 0.09 mm (paired t-test each, P<0.05). CCT and IOLT remained constant during accommodation (P > 0.05). The non-accommodative AL was 23.47 ± 0.93 mm, and it increased by +0.04 ± 0.04 mm after accommodation (P<0.01). The AL increased and the IOL moved backward during pilocarpine-induced accommodation in pseudophakic eyes.

Apparent accommodation in pseudophakic eyes with refractive against-the-rule, with-the-rule and minimum astigmatism

AimTo compare the magnitude of apparent accommodation in pseudophakic eyes with refractive against-the-rule (ATR), with-the-rule (WTR) and minimum astigmatism. Factors associated with apparent accommodation were also examined in each group.MethodsIn...

Effect of Astigmatism on Apparent Accommodation in Pseudophakic Eyes

To investigate the factors affecting apparent accommodation in pseudophakic eyes from a clinical viewpoint and the effects of corneal and refractive astigmatism on this accommodation from an optical viewpoint. We retrospectively examined 62 eyes of 33 patients who had undergone phacoemulsification with monofocal intraocular lens implantation. We quantitatively assessed the amplitude of apparent accommodation using an accommodometer 3 months after surgery. Multiple regression analysis was used to assess the factors affecting apparent accommodation. We also estimated the accommodation in eyes with corneal astigmatism by optical simulation. The mean amplitude of apparent accommodation was 1.58 = 0.65 D. Explanatory variables relevant to this accommodation were in order of influence, pupil diameter (partial regression coefficient B = 0.293, p = 0.008), and corneal multifocality (B = 0.101, p = 0.03). Other explanatory variables such as age, gender, axial length, corneal astigmatism, and refractive astigmatism showed no significant relationship with this accommodation. The estimated apparent accommodations for a 3.0 mm pupil by optical simulation were 1.25, 1.25, 1.25, 0.75, and 0 D, in eyes with corneal astigmatism of 0, 0.5, 1.0, 1.5, and 2.0 D, respectively. Similar results were obtained for a 4.0 mm pupil. Eyes with smaller pupil diameter and eyes with greater corneal multifocality are more predisposed to have greater apparent accommodation. However, from clinical and optical viewpoints, corneal or refractive astigmatism does not significantly contribute to apparent accommodation after cataract surgery, suggesting that it may be of less significance that the astigmatism is consciously retained in consideration of this accommodation in astigmatic eyes.

Examination of accommodation in pseudophakic eyes

Some patient with monofocal intraocular lens can achieve good near visual acuity with distance correction after cataract surgery. Understanding and measuring this phenomenon also called pseudoaccommodation can help to develop new technology to substitute or restore accommodation in pseudophakic eyes. I. To measure accommodation after cataract surgery. II. To measure anterior chamber depth with Scheimpflug imaging and comparing results with standard, ultrasonic data. III. To compare anterior chamber depth data, repeatability, reproducibility and reliability with a new optical device, the anterior segment optical coherent tomography (Visante OCT) and immersion ultrasound method in phakic eyes. I. We observed accommodation with defocusing technique, partial coherent interferometry method and measuring anterior chamber depth changing during ciliary muscle blocking. II. We measured anterior chamber depth with Pentacam and data were compared to standard ultrasonic method in phakic and pseudophakic eyes. III. We analyzed anterior chamber depth data, repeatability, reproducibility and reliability obtained by two observers using Visante OCT. I. A total accommodation amplitude of 0,83 D was observed with defocusing technique. Intraocular lens movement were negligible measured by partial coherent interferometry method using physiological accommodation stimulus. Mean movement of intraocular lens was 0.18 mm during blocking of the ciliary muscle. II. Pentacam and ultrasonic device measure the same anterior chamber depth in phakic eyes, but in pseudophakic eyes optical method measures significantly shallower anterior chamber depth. III. Anterior segment optical coherent tomography measures deeper anterior chamber depth than immersion ultrasonic device in phakic eyes. Accomodation and pseudoaccommodation observed in pseudophakic eyes is hard to measure and only parts of this process can be measured with each technique. Anterior chamber depth data varies by the measuring technique. Repeatability, reproducibility and reliability of anterior chamber depth data were better with optical technique.

Effect of total higher-order aberrations on accommodation in pseudophakic eyes

To analyze the effect of total higher-order aberrations (HOAs) on the range of accommodation in pseudophakic eyes and the size of near-vision optotypes. Department of Ophthalmology, Nara Medical University, Nara, Japan. The study comprised 30 patients (44 eyes) who were diagnosed with cataract at Nara University of Medical Science Hospital and Municipal Oyodo Hospital. Inclusion criteria included no other eye disorder and a best corrected distance acuity of 20/20 or better 1 month after cataract surgery. All patients had small-incision phacoemulsification followed by in-the-bag implantation of a monofocal intraocular lens (SA60AT, Alcon). All incisions were self-sealing. Accommodation in pseudophakic eyes was measured by the lens-loading method in an examination room under constant illumination. Ocular HOAs were measured using the KR-9000PW Hartmann-Shack wavefront analyzer (Topcon). The mean patient age was 75.8 years +/- 5.4 (SD) (range 64 to 83 years). The Pearson correlation coefficient (r) showed a significant positive correlation between the range of accommodation and Z7 (vertical coma) for a 4.0 mm pupil using the 1.0 near-vision optotype. There was a significant negative correlation between the range of accommodation and Z12 (spherical aberration) for a 4.0 mm pupil using the 1.0 near-vision optotype (r = .311, P = .040 for Z7;r = -.365, P = .015 for Z12). No other parameter was significantly correlated with the range of accommodation. Measurement of accommodation in pseudophakic eyes by the lens-loading method using the 1.0 near-vision optotype showed that eyes with larger vertical coma aberrations achieved a larger range of accommodation. In contrast, eyes with larger spherical aberrations had smaller amounts of accommodation. The size of the near-vision optotype may affect accommodation analysis in pseudophakic eyes.

Comparison of amplitude of apparent accommodation in pseudophakic eyes with that of normal accommodation in phakic eyes in various age groups

To compare the amplitude of apparent accommodation in eyes with monofocal intraocular lenses with that of normal accommodation in the phakic fellow eyes in various age groups. In all, 130 eyes of 130 patients scheduled to undergo cataract surgery, and 130 fellow eyes that had little cataract and good visual acuity of 20/33 or better were studied. The following groups were studied: in their 40s and younger (n = 20) or in their 50s (n = 30), 60s (n = 30), 70s (n = 30), and 80s (n = 20). Using an accommodometer (Kowa HS-9E), the accommodative amplitude was measured at 1 month after surgery. In the patients in their 40s and younger or in their 50s, the amplitude of apparent accommodation was significantly less than that of normal accommodation; no significant difference was observed in the patients in their 60s, 70s, or 80s. The incidence of patients in whom the amplitude of apparent accommodation was more than that of normal accommodation was greater in the patients in their 60s, 70s, and 80s than in the patients in their 40s and younger and in their 50s. The amplitude of apparent accommodation is virtually equivalent to that of normal accommodation in patients older than 60 years of age.

Determination of pseudophakic accommodation with translation lenses using Purkinje image analysis

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. 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. 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. 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.

Relationship between apparent accommodation and corneal multifocality in pseudophakic eyes

Objective To investigate whether any association exists between apparent accommodation in pseudophakic eyes and multifocal corneal effects. Design A prospective observational case series. Participants A total of 121 eyes of 98 patients who had undergone phacoemulsification and posterior chamber intraocular lens implantation were studied. Methods The amount of apparent accommodation was measured using an accommodometer. The degree of corneal multifocality was determined on the corneal topography by measuring the maximum and minimum corneal refractive powers within the pupillary area. Refractive astigmatism, keratometric astigmatism, pupillary diameter, and age were also analyzed. Main outcome measures Apparent accommodation, corneal multifocality, refractive and keratometric astigmatism, pupillary diameter, and age. Results Multiple regression analysis revealed that corneal multifocality and pupillary diameter had significant positive correlations with apparent accommodation, whereas other explanatory variables showed no relationship with apparent accommodation. Conclusion Multifocal corneal effects contribute to apparent accommodation in pseudophakic eyes.

Apparent accommodation in pseudophakic eyes

The so-called apparent accommodation has been measured in patients implanted with anterior chamber, iris support and posterior chamber IOLs. The data have been related to pupillary diameter and anterior chamber depth in order to explain the actual possibility of a near vision with optical correction only for distance.

Apparent Accommodation in Pseudophakic Eyes after Implantation of Posterior Chamber Intraocular Lenses

We measured apparent accommodation in 42 pseudophakic eyes (34 patients) after implantation of posterior chamber intraocular lenses. The mean apparent accommodation was 2.03 +/- 1.03 diopters. The mean accommodative power of 16 phakic eyes used as controls was 2.91 +/- 1.29 diopters. The diameter of the pupil appeared to be the most important factor in apparent accommodation--the smaller the pupil, the greater the apparent accommodation. Apparent accommodation was inversely proportional to the pupillary diameter. There was no correlation, however, between apparent accommodation and corrected visual acuity, refractive error, corneal astigmatism, or axial length. There was a negative correlation between apparent accommodation and anterior chamber depth.