Ultrasound biomicroscopy of ZSAL-4 anterior chamber phakic intraocular lens for high myopia

Explaining The Current Role Of High Frequency Ultrasound In Ophthalmic Diagnosis (Ophthalmic Ultrasound)

Ultrasound has become as indispensable as indirect ophthalmoscopy or slit lamp in evaluation of the eye. It is an important adjuvant for the clinical assessment of a variety of ocular and orbital diseases. Advances in instrumentation, higher frequencies and more sensitivity and resolution have resulted in continuous improvement in image quality.Very high frequency ultrasound uses frequencies in the range of 35 to 100 MHz to show greater detail of the anterior segment. Penetration is limited for these higher frequencies to only a few millimeters and thus only the anterior vitreous behind the ciliary body and lens can be imaged. High frequency ultrasound in the range of 20 to 30 MHz has a penetration of about 10 mm and can be used for posterior pole evaluation of the retina and choroid.

Ultrasound biomicroscopy characterization of acrylic, silicone, and polymethyl methacrylate lenses in vitro

BACKGROUND

This study aims to characterize the reflective properties of some commonly used intraocular lenses (IOLs) in vitro, with a particular focus on lens haptics.

METHODS

Six different types of IOLs, representative of silicone, acrylic, and polymethyl methacrylate (PMMA), single, multipiece, and multifocal were imaged using high-resolution ultrasound biomicroscopy (UBM).

RESULTS

Reflectivity patterns were distinct to the material that was being imaged irrespective of whether the part being imaged was the haptic or optic. Acrylic haptics demonstrated a single "tram-track" reduplication echo, whereas PMMA haptics showed multiple reverberation echoes off the posterior surface. The optics of various PMMA and acrylic lenses demonstrated a reflectivity pattern similar to the respective haptics made of the same material. Silicone optics displayed clear delineation with no reverberation. Both acrylic and silicone material was relatively less reflective when compared with PMMA.

INTERPRETATION

With UBM imaging, the haptics of acrylic and PMMA IOLs demonstrate unique reflective patterns, depending on the material being studied. Prior knowledge of what the lens haptics and optics look like in vitro provides information that may assist in identifying and localizing misplaced intraocular lenses in vivo.

Outcomes of ZB5M Angle-supported Anterior Chamber Phakic Intraocular Lenses at 12 Years

PURPOSE

To evaluate the visual and refractive stability and the potential long-term risks associated with ZB5M phakic intraocular lens (PIOL) implantation.

METHODS

A retrospective, non-randomized, cumulative clinical study was performed over 12 years in a consecutive group of 225 eyes implanted with the ZB5M PIOL. The main analyzed variables were visual and refractive outcomes (best spectacle-corrected visual acuity [BSCVA], uncorrected visual acuity [UCVA], and spherical equivalent), endothelial cell density, and postoperative complications.

RESULTS

Mean preoperative spherical equivalent refraction was -17.23 +/- 7.69 diopters (D) and 12 years postoperatively it was -1.80 +/- 0.80 D. Mean BSCVA at 1- and 12-year follow-up was 0.38 +/- 0.19 and 0.57 +/- 0.18, respectively (Wilcoxon test, P < .001). At 12 years postoperatively, 3.5% of eyes lost > or = 2 lines of BSCVA. An initial 10.6% reduction in endothelial cell density was noted in the first year, followed by a mean annual rate of decrease of 1.78%. The cumulative incidence of pupil ovalization was 34.7% (78 eyes), and there was no statistical correlation with endothelial cell impairment. Bilateral hypertensive uveitis was diagnosed in 3 (1.33%) eyes.

CONCLUSIONS

The ZB5M PIOL offers good refractive outcomes and stability in the long-term; however, endothelial cell loss increases over 12 years, requiring annual endothelial cell counts.

Correction of high myopia with different phakic anterior chamber intraocular lenses: ICARE angle-supported lens and Verisyse iris-claw lens

PURPOSE

To evaluate the efficacy, predictability and safety of implanting two models of anterior chamber IOLs for high myopia. Comparison of the refractive results between two groups of patients implanted with different IOLs.

MATERIALS AND METHODS

Forty eyes were implanted with phakic IOLs. The ICARE myopia lens was implanted in 20 eyes of 12 patients with preoperative myopia that ranged from -21.875 to -10.0. The mean patients' age was 30 years. The Verisyse IOL was implanted in 20 eyes of 12 patients with spherical equivalent of the refractive error from -21.625 to -10.375D, and the mean patients' age was 32.25 years. The dioptric power of the intraocular lens was calculated by considering refraction, keratometry, and anterior chamber depth. The follow-up period was 12 months.

RESULTS

Twelve months after surgery, the mean refractive error (SE) was -0.19D (100% of eyes were within +/-1.0D of the target refraction) in the ICARE group, and -0.86D (95% of eyes were within +/-1.0D of the target refraction) in the Verisyse group. The postoperative refraction remained stable during the entire follow-up period. The mean uncorrected visual acuity was 0.7 in the ICARE group, and 0.69 in the Verisyse group 1 year postoperatively. There was no loss in visual acuity 1 year after surgery in the ICARE implanted eyes, one patient in the Verisyse group lost 1 line of BCVA as compared to the preoperative state. Mean endothelial cell density loss was 6.12% and 6.79% in the ICARE and Verisyse groups, respectively. There were no statistically significant differences regarding the analyzed outcome parameters between the two study groups.

CONCLUSION

The implantation of both anterior chamber phakic intraocular lenses to correct high myopia resulted in a stable and predictable refractive outcome. Efficacy and safety of surgery for both implanted lens models are very high.

Iridocyclitis associated with angle-supported phakic intraocular lenses

PURPOSE

To evaluate incidence, features, risk factors, and prognosis of iridocyclitis after angle-supported phakic intraocular lens (IOL) implantation.

SETTING

Private practice, Siena, Italy.

METHODS

This retrospective analysis comprised 356 consecutive eyes of 212 patients. In myopic eyes, the ZSAL-4 IOL (205 eyes of 125 patients) or the ZSAL-4 Plus IOL (106 eyes of 63 patients) was used. In hyperopic eyes (45 eyes of 24 patients), the Type 54 IOL was implanted. Haptic posterior angulation was 19 degrees (ZSAL-4), 23 degrees (ZSAL-4 Plus), and 14 degrees (Type 54).

RESULTS

Clinically significant iridocyclitis occurred in 11 eyes (3.1%) of 11 patients. Mean patient age was 37.3 years +/- 9.4 (SD). Sixty-four percent were male (odds ratio [OR], 3.0; 95% confidence interval [CI], 0.8 to 7.4, not statistically significant). Iridocyclitis was observed in 4.4% of hyperopic eyes (OR, 1.6; 95% CI, 0.3 to 7.4; not statistically significant) and in 2.9% of myopic eyes. In myopic eyes, it followed the implantation of ZSAL-4 IOL in 3.9% of eyes (OR, 4.1; 95% CI, 0.5 to 33.6; not statistically significant), and of ZSAL-4 Plus IOL in 1%. Mean time from surgery was 8.5 +/- 10.6 months). Presentation included aqueous flare (100%), posterior synechiae (82%), blurred vision (82%), redness (36%), pain (27%), IOL precipitates (18%), and angular synechiae (9%). Only 1 patient had recurrences, leading to IOL explantation and cataract surgery. After topical therapy, best spectacle-corrected visual acuity was fully recovered in 9 of 11 eyes.

CONCLUSION

Iridocyclitis can occur months or years after the implantation of angle-supported phakic IOLs. No statistically significant risk factors were identified. Functional prognosis is generally good.

Phakic Intraocular Lenses

An analytical review of the data available in the field of phakic intraocular lens implantation was conducted. Particular attention was paid to the more critical issues of intraocular lens sizing and safety guidelines. A comprehensive, competitive analysis of different implantation sites, intraocular lens model designs, and safety guidelines has been included. Specialized biometry techniques, such as very high frequency ultrasound and Scheimpflug imaging, have been reviewed, and a critical review of commercial claims regarding intraocular lens technologies has been included. Clinical studies of phakic intraocular lenses demonstrate increasing promise for the correction of refractive errors not amenable to mainstream excimer laser refractive surgery. The main issues currently revolve around adequate lens design (VHF ultrasound study suggests that custom-design and sizing may be the most effective and safest approach for every phakic IOL model), because these devices will be required to remain physiologically inert and anatomically compatible with internal ocular structures and relations for several decades. The possibility of safe removing or exchanging the IOL should remain a feasible option over time. It is of utmost importance that we continue to critically evaluate current encouraging short-term outcomes, which are being extrapolated to the longer term by ongoing high resolution imaging and monitoring of the anatomical and functional relations of implanted phakic IOLs.

Ultrasound biomicroscopy of silicone posterior chamber phakic intraocular lens for myopia

PURPOSE

To study the intraocular position and anatomic relationships of PRL-III (phakic refractive lens) (PRL) posterior chamber phakic intraocular lens (PCP IOL) for high myopia using ultrasound biomicroscopy (UBM).

SETTING

Centro Oftalmológico Real Vision, and Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Universidad Complutense de Madrid, Madrid, Spain.

METHODS

Sixteen phakic myopic eyes that had had PRL implantation were examined by UBM 1 month after surgery. The PRL position, PRL-crystalline lens peripheral distance, and central distance between the corneal endothelium and the PRL were measured.

RESULTS

Both haptics were on the zonule in 6 eyes, in the ciliary sulcus in 5 eyes, and impacted in the ciliary body in 1 eye. In the 4 remaining eyes, the haptics were in mixed positions. The mean PCP IOL crystalline lens peripheral distance in the minor axis was 588.1 microm +/- 232.5 (SD), and the mean PCP IOL-endothelium central distance was 2082.8 +/- 277.6 microm.

CONCLUSIONS

Phakic refractive lens implantation should be done carefully because of the sulcus location of the haptics in many cases. This, with the iris-PRL contact, suggests caution for the long-term outcome.

High-frequency ultrasound biomicroscopy of silicone posterior chamber phakic intraocular lens for hyperopia

PURPOSE

To study the intraocular position and anatomic relationships of the PRL-III phakic refractive lens (PRL), a posterior chamber phakic intraocular lens (PCP IOL), in cases of hyperopia using ultrasound biomicroscopy (UBM).

SETTING

Centro Oftalmológico Real Vision, Madrid, Spain, and Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Universidad Complutense, Madrid, Spain.

METHODS

Eleven phakic hyperopic eyes of 6 patients who had PRL implantation were examined by UBM 1 month after surgery. The PRL position, PRL-crystalline lens peripheral distance, and central distance between the corneal endothelium and the PRL were measured.

RESULTS

Eight eyes had both haptics on the zonule, 2 had 1 haptic in the sulcus and 1 on the zonule, and 1 had 1 haptic in the sulcus and the other in the ciliary body. The mean PCP IOL-crystalline lens peripheral distance in the minor axis was 239.7 microm +/- 179.4 (SD) and the mean PCP IOL-endothelium central distance, 2146.98 +/- 219.6 microm. Contact between the PCP IOL and crystalline lens was observed in 1 eye.

CONCLUSIONS

In this study of hyperopic eyes, the PRL was located on the zonule in most cases. However, the location of the haptics in the sulcus and contact between the PCP IOL and the crystalline lens that occurred in some cases suggest further study of possible long-term complications is needed.

Ultrasound biomicroscopy examination of posterior chamber phakic intraocular lens position

OBJECTIVE

To better elucidate the in vivo position of the Collamer posterior chamber phakic intraocular lens (PCPIOL) and its relationship to the iris and the crystalline lens and to analyze possible variations over time.

DESIGN

Prospective observational case series.

PARTICIPANTS

Eighteen eyes of nine patients were included.

INTERVENTION

A Staar Collamer implantable PCPIOL was implanted for the correction of high myopia.

MAIN OUTCOME MEASURES

The eyes were studied with a 50-MHz ultrasound biomicroscopy UBM 840. The exact PCPIOL position and the distances between it and the crystalline lens were measured at 3, 6, and 12 months after surgery.

RESULTS

There were no intraoperative complications. In 13 eyes (72.22%), contact between the PCPIOL and the crystalline lens was found at some time during follow-up. In 3 eyes (16.6%), central contact could be demonstrated. We also observed that the contact zone and its extension can vary over time. In 2 eyes, rotation of the lens was observed.

CONCLUSIONS

We found contact between the PCPIOL and the crystalline lens in a high percentage of cases. There was also mobility of the lens in the posterior chamber, especially in the anteroposterior plane, and, as a consequence, both the contact zone and its extension would vary over time.

Ultrasound biomicroscopy of the Artisan phakic intraocular lens in hyperopic eyes

PURPOSE

To study in situ the intraocular position of the Artisan iris-claw intraocular lens (IOL) (model 203) (Ophtec) in phakic hyperopic eyes using ultrasound biomicroscopy (UBM).

METHODS

Echograms of the anterior chamber were taken preoperatively and 24 to 317 days postoperatively in 4 eyes implanted with the Artisan IOL (power +4.0 to +6.0 diopters). The preoperative anterior chamber depth (ACD) and the postoperative distance between the IOL and the corneal endothelium (endothelium-optic distance) and between the IOL and the lens were measured. The echograms were assessed for the effect of the IOL on iris tissue.

RESULTS

The preoperative ACD ranged from 3.10 to 3.56 mm and the postoperative endothelium-optic distance, from 2.03 to 2.54 mm. The distance between the lens and the posterior surface of the IOL ranged from 0.35 to 0.79 mm. Several UBM echograms showed indentation of iris tissue by the IOL haptics and optic edge, although no pigmentary dispersion was noted.

CONCLUSIONS

Adequate space was maintained between the Artisan hyperopic IOL and the corneal endothelium, angle, and crystalline lens. Haptic indentation of the iris, which could lead to pigment erosion, was observed. Preoperative gonioscopy and maintenance of normal intraocular pressure postoperatively suggest the indentation was secondary to inadequate lens vaulting relative to the high natural arch of the iris in hyperopic eyes. Shortening the haptics or increasing the lens vault might resolve this problem.