Dynamic Stimulation Aberrometry: Objectively Measured Accommodation and Pupil Dynamics after Phakic Iris-Fixated Intraocular Lens Implantation

Purpose

Anterior iris-claw phakic intraocular lens (pIOL) implantation is a treatment option for refractive, ametropic patients. However, the postoperative accommodative ability has not been systematically researched. Dynamic stimulation aberrometry allows the objective and dynamical measurement of accommodation by observing ocular aberrations during the accommodation process. We investigated the dynamic accommodative ability after pIOL implantation compared with a healthy age- and gender-matched control group.

Design

Clinical, comparative case-control study.

Subjects

We included patients aged 18-50 years that either underwent pIOL implantation > 1 month ago or served as a healthy, phakic control group.

Methods

The accommodative ability and pupil dynamics of both groups were investigated using dynamic stimulation aberrometry. The method allows the analysis of dynamic parameters during accommodation, such as the accommodation speed. A 1:1 propensity score matching was conducted based on the patients' age and gender.

Main Outcome Measures

Parameters of objective accommodation, such as accommodative amplitude and pupil dynamic during accommodation.

Results

Fifty-eight healthy, phakic eyes < 50 years of age and 21 eyes after pIOL implantation to correct myopia (pIOL, Verisyse, AMO, Inc) were enrolled. Patients that underwent anterior pIOL implantation were examined on average 24 ± 18 months after surgery. After matching, the mean age of both groups was not significantly different (35 ± 8 vs. 34 ± 8 years). No significant difference in dynamic parameters of accommodation or the accommodative amplitude (2.8 ± 1.4 and 2.9 ± 1.4 diopters [D] for pIOL and control group, P = 0.82) were seen. Maximum and minimum pupil sizes were not significantly different. The change in pupil size during deaccommodation was significantly faster in patients after pIOL implantation (P < 0.001).

Conclusions

Dynamic stimulation aberrometry allowed the objective, dynamic, measurement of wavefronts in subjects with accommodative amplitudes up to 7 D. Phakic intraocular lens implantation does not impair the accommodative ability. It alters pupil dynamics during deaccommodation.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Baerveldt drainage tube motility in the anterior chamber

PURPOSE

To investigate the stability in position of the Baerveldt glaucoma drainage tube over time and to study movement of the drainage tube in the anterior chamber (AC) under varying light conditions.

METHODS

This prospective study included 70 eyes with implantation of a Baerveldt glaucoma drainage tube in the anterior chamber. Anterior segment optical coherence tomography (AS-OCT) images were made preoperatively to quantify AC depth. AS-OCT images were made twice under photopic and twice under scotopic conditions, in the angle parallel to the Baerveldt tube to quantify drainage tube position, at 3, 6, 12, and 24 months postoperatively. Tube-corneal (T-C) and tube-iris (T-I) distances were measured. Additionally, the central AC depth and the peripheral angle opening (AOD 500) were determined. Two subgroups were distinguished according to tube position: free in the AC (group 1, n = 48) and transiridal (group 2, n = 22).

RESULTS

After 24 months of follow-up, the drainage tube was found to move statistically significantly closer (0.12 mm) to the corneal endothelium in group 1 (p<0.01). There was no statistically significant difference in T-C distance over time in group 2. The T-C distance did not differ under photopic versus scotopic circumstances (p = 0.32). In both groups, the T-I distance was larger under scotopic conditions, a result of pupil dilation.

CONCLUSIONS

The Baerveldt glaucoma drainage tube remained in a stable position when a transiridal implantation was performed, whereas the tube moved closer to the endothelium when placed free into the AC. Transiridal implantation of the Baerveldt tube seems a safe alternative for tube implantation with respect to tube motility.

Rotation stability of the cachet angle-supported phakic intraocular lens

PURPOSE

To evaluate the rotational stability of an acrylic angle-supported phakic intraocular lens (PIOL) 12 months after implantation in myopic eyes.

METHODS

Patients with a history of moderate to high myopia underwent unilateral or bilateral implantation of an acrylic angle-supported PIOL (AcrySof Cachet; Alcon Laboratories, Inc., Fort Worth, TX). All were followed up for 12 months. IOL rotation was assessed using digital overlay of ocular photographs captured within 2 weeks of implantation and at postoperative month 12. The secondary outcomes of refractive power (spherical equivalent, refractive sphere, and cylinder) and uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were assessed preoperatively and again at 3 months after implantation.

RESULTS

Fifty eyes of 28 patients with a mean age of 32 years were included in this retrospective cohort study. All underwent successful IOL implantation and follow-up. A mean 12-month rotation of 11° was observed (standard deviation: 15.1°, range: 0 to 60°). All preoperative measures (mean) of refractive power improved by 3 months postoperatively (spherical equivalent = -0.35 ± 0.79 diopters [D], spherical refraction = 0.04 ± 0.82 D, and cylindrical refraction = -0.77 ± 0.91 D). Two percent of eyes requiring additional laser adjustment by postoperative month 12, primarily due to corneal astigmatism.

CONCLUSION

The study findings suggest that AcrySof Cachet angle-supported PIOLs offer moderate 1-year rotational stability. Because this type of IOL also corrects myopia effectively, it appears to be a good treatment option for myopic eyes. However, the rotation that occurs makes it unsuitable for cylinder corrections.

Three-year follow-up of secondary anterior iris fixation of an aphakic intraocular lens to correct aphakia

PURPOSE

To evaluate the efficacy, predictability, stability, safety, and complications of secondary anterior iris fixation of the Artisan iris-fixated intraocular lens (IOL) to correct aphakia in eyes without sufficient capsule support.

SETTING

Department of Ophthalmology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China.

DESIGN

Cohort study.

METHODS

Eyes having implantation of aphakic iris-fixated IOLs for aphakia correction were followed for 3 years.

RESULTS

The study evaluated 72 eyes (72 patients). After 3 years, the uncorrected distance visual acuity improved in all eyes (P<.05); 53 eyes (73.6%) reached 20/40 or better. Two eyes had a postoperative corrected distance visual acuity (CDVA) worse than the preoperative CDVA due to postoperative ischemic optic neuropathy and retinal detachment, respectively. The mean spherical equivalent (SE) decreased from 11.65 diopters (D) ± 1.21 (SD) to -0.58 ± 0.56 D (P<.05); the SE at the last follow-up was within ±1.00 D of the target refraction in 63 eyes (87.5%). The mean endothelial cell loss 3 years postoperatively was 9.78%. There was no significant postoperative intraocular pressure increase throughout the follow-up. Twelve patients (16.7%) reported glare and halos during night driving. Iris pigment precipitates on the IOLs occurred in 4 eyes (5.6%) 3 years postoperatively. No other serious complications occurred.

CONCLUSIONS

Three-year results indicate that secondary implantation of aphakic IOLs is effective, predictable, and safe for the correction of aphakia in eyes without capsule support. However, longer follow-up with a larger cohort is necessary to confirm these conclusions.

Intraocular stability of an angle-supported phakic intraocular lens with changes in pupil diameter

PURPOSE

To use anterior segment optical coherence tomography (AS-OCT) to evaluate the stability of a recently released angle-supported phakic intraocular lens (pIOL) in the anterior segment with changes in pupil diameter.

SETTING

Keratoconus Unit, Vissum Corporation, Alicante, Spain.

METHODS

In this observational cross-sectional study of consecutive eyes with moderate to high myopia, an AcrySof Cachet pIOL was implanted with the aim of minimizing the refractive error. An analysis of the position and stability of the pIOL before and after pharmacologic pupil dilation was performed 3 months postoperatively using the Visante AS-OCT system. A measurement protocol that included several anatomic parameters was developed and applied; the parameter values before and after dilation were compared.

RESULTS

Twenty eyes of 20 patients ranging in age from 24 to 48 years old were evaluated. The anterior chamber depth increased significantly with pupil dilation (mean change 0.06 mm +/- 0.08 [SD]) (P<.01). A significant change was also observed in the distance between the center of the cornea at the endothelial plane and the anterior surface of the pIOL (mean change 0.03 +/- 0.05 mm) (P = .01). The distances between the peripheral edges of the pIOL and the corneal endothelium and the distance between the crystalline lens and the pIOL did not change significantly (P>or=.14).

CONCLUSION

The angle-supported pIOL showed excellent intraocular behavior after pupil dilation, with no shortening of the distance between the pIOL and corneal endothelium at the center or peripheral edges of the pIOL.