Behaviour of the phakic iris-claw intraocular lens (Artisan /Verisyse) during accommodation: an optical coherence biometry study

Visual performance after implantation of two types of phakic foldable intraocular lenses for correction of high myopia

AIM

To compare Visian lens (model V4c) and Artiflex lens regarding quality (contrast sensitivity) and quantity (efficacy, predictability, safety and stability) of vision in correcting high myopia with recording and analysis of complications.

METHODS

The comparative prospective study included 39 eyes of 23 patients with high myopia, 19 eyes had Visian lens implantation (model V4c) and 20 eyes had Artiflex lens implantation. The inclusion criteria were high myopia (higher than 6.0 D) and stable refraction (<0.5 D change over one year). Outcomes included assessment of safety and efficacy indices, predictability, stability, contrast sensitivity and analysis of complications at postoperative 1d, 1wk and 1, 3, 6 and 12mo. Selection of the type of phakic intraocular lens for patients was based on surgeons' preferences, which was no specific selection criteria.

RESULTS

After 12mo of follow up, difference in uncorrected and corrected distant visual acuity (CDVA) between both groups was statistically insignificant (UDVA for VisianV4c and Artiflex lens were 0.33±0.2 logMAR and 0.37±0.2 logMAR respectively, P=0.59, CDVA for VisianV4c and Artiflex lens were 0.155±0.1 logMAR and 0.147± 0.1 logMAR respectively, P=0.87). The efficacy index was 1.25 for VisianV4c lens and 0.8 for Artiflex lens, 78.9% of eyes were within one diopter spherical equivalent in Visian V4c lens group compared to 70% in the Artiflex lens group. No eye lost lines of CVDA proving a good safety index for both lenses (safety index was 1.67 for VisianV4c lens and 1.34 for Artiflex lens). Difference in contrast sensitivity between both groups was statistically insignificant (P=0.15, 0.88, 0.27, 0.32 and 0.82 at five spatial frequencies).

CONCLUSION

Both Visian ICL V4c and Artiflex lenses are safe and effective with stable and predictable refraction and they have comparable contrast sensitivity outcomes with no vision threatening complications.

[Retropupillary iris claw intraocular lens implantation technique for aphakia]

BACKGROUND

Overview of the retropupillary implantation of iris claw intraocular lenses (Artisan®,Ophtec, Groningen, Niederlande and Verisyse(TM),AMO, Santa Ana CA).

MATERIAL AND METHODS

A literature search and review of implantation techniques, patient selection, potential complications and management strategies.

RESULTS

This approach has the advantage of a simple implantation technique, an anatomically correct implantation site (as compared to endocapsular implantation) and a relatively low complication rate. An intact iris is, however, a prerequisite for this technique. Ischemic vitreoretinopathies, such as diabetes or vascular occlusive entities, as well as uveitis might be considered as contraindications.

CONCLUSIONS

The retropupillary implantation of iris claw intraocular lenses is an interesting and especially time-effective rehabilitation technique for aphakia.

Using a slit lamp-mounted digital high-speed camera for dynamic observation of phakic lenses during eye movements: a pilot study

Purpose

To evaluate a digital high-speed camera combined with digital morphometry software for dynamic measurements of phakic intraocular lens movements to observe kinetic influences, particularly in fast direction changes and at lateral end points.

Materials and methods

A high-speed camera taking 300 frames per second observed movements of eight iris-claw intraocular lenses and two angle-supported intraocular lenses. Standardized saccades were performed by the patients to trigger mass inertia with lens position changes. Freeze images with maximum deviation were used for digital software-based morphometry analysis with ImageJ.

Results

Two eyes from each of five patients (median age 32 years, range 28–45 years) without findings other than refractive errors were included. The high-speed images showed sufficient usability for further morphometric processing. In the primary eye position, the median decentrations downward and in a lateral direction were −0.32 mm (range −0.69 to 0.024) and 0.175 mm (range −0.37 to 0.45), respectively. Despite the small sample size of asymptomatic patients, we found a considerable amount of lens dislocation. The median distance amplitude during eye movements was 0.158 mm (range 0.02–0.84). There was a slight positive correlation (r=0.39, P<0.001) between the grade of deviation in the primary position and the distance increase triggered by movements.

Conclusion

With the use of a slit lamp-mounted high-speed camera system and morphometry software, observation and objective measurements of iris-claw intraocular lenses and angle-supported intraocular lenses movements seem to be possible. Slight decentration in the primary position might be an indicator of increased lens mobility during kinetic stress during eye movements. Long-term assessment by high-speed analysis with higher case numbers has to clarify the relationship between progressing motility and endothelial cell damage.

Accommodative changes in anterior chamber depth in patients with high myopia

PURPOSE

To study the accommodative changes in the central anterior chamber depth (ACD) in patients with high myopia using anterior segment optical coherence tomography (AS-OCT).

SETTING

Cataract Surgery Department and Clinical & Functional Diagnostics Department, S. Fyodorov Eye Microsurgery Complex-Federal State Institution, Moscow, Russian Federation.

DESIGN

Prospective case-control study.

METHODS

The ACD measurements were obtained in the nonaccommodative state (baseline) and during accommodation using the Visante AS-OCT device.

RESULTS

Thirty-six myopic eyes (36 patients; mean age 27 years; mean spherical equivalent (SE) -12.52 diopters [D]) and 31 emmetropic eyes (31 subjects; mean age 26 years; mean SE -0.39 D) were examined. At baseline, the mean ACD in both groups was similar. During accommodation, the mean maximum changes in the ACD were significantly less pronounced in the myopia group (-0.14 mm ± 0.07 [SD]; range -0.03 to -0.29 mm) than in the emmetropia group (-0.22 ± 0.08 mm; range -0.04 to -0.35 mm) (P<.0001). Ten patients in the myopia group had a critically shallow anterior chamber (ACD <2.8 mm) in the state of accommodation.

CONCLUSIONS

Accommodative changes in the ACD were significantly less pronounced in eyes with high myopia than in emmetropic eyes. Still, the anterior chamber might become critically shallow during accommodation in some myopic eyes, and this should be taken into account when planning phakic intraocular lens implantation to correct high myopia.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Transient myopic shift after phakic intraocular lens implantation

Three patients presented with spontaneous myopic shift 6 weeks to 6 months after implantation of the Artiflex phakic intraocular lens (pIOL). The corrected distance visual acuity (CDVA) was maintained in all cases. Cyclopentolate drops successfully reverted the myopic shift in all cases; however, 2 cases required surgical reenclavation of the pIOL haptics to achieve long-term refractive stability. At the last follow-up, all patients had returned to emmetropia, with uncorrected distance visual acuities of 20/20. A slight decrease in objective optical quality was observed. No eye lost a line of CDVA. In 1 eye, optical coherence tomography scans showed slight posterior positioning of the pIOL. These cases show that spontaneous myopic shift is a potential complication of iris-claw pIOL implantation. That cyclopentolate drops and/or reenclavation of the haptics were effective in reverting the situation suggests a mechanical mechanism related to iris and ciliary body dynamics.

FINANCIAL DISCLOSURE

Dr. Güell is a consultant to Ophtec. No author has a financial or proprietary interest in any material or method mentioned.