Phakic intraocular lenses

White-to-white corneal diameter differences in moderately and highly myopic eyes: partial coherence interferometry versus scanning-slit topography

PURPOSE

To evaluate the differences between Orbscan scanning-slit topography and IOLMaster partial coherence interferometry (PCI) white-to-white (WTW) measurements in moderately and highly myopic eyes.

SETTING

IOBA-Eye Institute, University of Valladolid, Spain.

DESIGN

Comparative case series.

METHODS

Myopic eyes were divided according to the degree of myopia as follows: Group 1 (<6.00 diopters [D]), Group 2 (between 6.00 D and 12.00 D), and Group 3 (>12.00 D). The WTW distance was measured with the scanning-slit topography and PCI devices.

RESULTS

The study enrolled 328 eyes (64 subjects). The mean WTW in all eyes was 0.50 mm ± 0.26 (SD), lower with scanning-slit topography (11.69 ± 0.37 mm) than with PCI (12.19 ± 0.40 mm) (P<.01, paired t test). A low mean WTW was found in Group 2 (11.65 ± 0.34 and 12.15 ± 0.36 mm, scanning-slit topography and PCI, respectively) and Group 3 (11.51 ± 0.36 and 12.05 ± 0.46 mm, respectively) compared with Group 1 (11.79 ± 0.38 and 12.26 ± 0.40 mm, respectively) (P<.03, analysis of variance with Games-Howell correction). There was a low statistically significant relationship between WTW and spherical equivalent (SE) with both devices.

CONCLUSIONS

Eyes with moderate and high degrees of myopia had lower WTW diameters than eyes with low spherical equivalent myopia measured with both devices. Scanning-slit topography provided less WTW distance than PCI in myopic eyes; thus, the devices are not clinically interchangeable.

Refractive surgery for accommodative esotropia: past, present, and future

INTRODUCTION

Refractive surgery has the potential to be a definitive treatment for accommodative esotropia, yet it has not been widely embraced. This article reviews the current literature on refractive surgery to treat accommodative esotropia.

METHODS

A literature search was performed using the following terms: refractive surgery, photorefractive keratectomy, laser-assisted keratomileusis, intraocular lens, hyperopia, accommodative esotropia, children, pediatric.

RESULTS

Fifteen series of patients treated with refractive surgery for accommodative esotropia were identified and summarized.

CONCLUSIONS

Refractive surgery holds promise for the treatment of accommodative esotropia, although treatment risks are present and additional investigation is needed.

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.

Suture fixation of iris-claw intraocular lens

We report a technique to surgically manage the damaged haptic of an iris-claw intraocular lens (IOL). An 89-year-old woman initially presented with a subluxated posterior chamber IOL that was exchanged for an Artisan iris-claw IOL. The IOL had been enclavated nasally and temporally, but it deenclavated nasally 4 weeks postoperatively. During surgery to reposition the IOL, 1 haptic of the nasal claw was seen to be damaged. It was sutured to the iris with 10-0 polypropylene using a CIF-4 needle. The postoperative outcome was good.

FINANCIAL DISCLOSURE

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

Toric implantable collamer lens implantation in a case with bilateral primary peripheral iris cysts

The authors describe a patient who was found to have bilateral, peripheral iris cysts during preoperative ultrasound biomicroscopy (UBM) assessment prior to toric implantable collamer lens (TICL) implantation. TICL implantation was undertaken with no intraoperative or postoperative complications. The TICLs remained in stable position over a follow-up period of 15 months. The presence of solitary temporal iris cysts had no impact on final visual outcome or TICL position.

Long-term evaluation of the central vault after phakic Collamer® lens (ICL) implantation using OCT

PURPOSE

The aim of this work is to evaluate the changes in the central vault after using implantable Collamer® lenses (ICL) to correct myopia.

METHODS

This cohort study included 133 eyes; mean spherical equivalent -9.47 ± 3.71 diopters (D) (range: -2.75 to -22.25 D) who underwent ICL V4 implantation. Besides a complete ophthalmologic examination, the central vaulting was measured with Visante OCT and evaluated between different periods of follow-up (1 week, 1, 3, and 6 months, and yearly postoperatively). Post-operative time ranged from 6 to 73 months.

RESULTS

Within the first 6 months, the mean central vaulting dropped from 510 ± 238 μm (range 100 to 940 μm) to 439 ± 231 μm (range 90 to 910) a significant decrease by 71 ± 58 μm (range -170 to 30 μm) (p = 0.028) with a trend to a lower reduction after this period. After 36 month from ICL implantation, this variation tends to be smaller with the majority of the eyes having a mean decrease smaller than 2 μm per month. Initial vault (Spearman Rho = -0.237, p = 0.006) was the factor more significantly associated with decrease in vault; eyes presenting a reduction in vault >100 μm had an average initial vault that was 141 μm and 184 μm higher than eyes with no change or with increase in vault over time, respectively.

CONCLUSIONS

This study shows a continuous reduction of central vault over time. The reduction is highest during the first 6 months and tends to be lower and slow down over time. The decrease of vaulting was more pronounced in eyes with larger initial vaulting.

Central vault after phakic intraocular lens implantation: correlation with anterior chamber depth, white-to-white distance, spherical equivalent, and patient age

PURPOSE

To compare the central postoperative vault of a phakic intraocular lens (pIOL) to correct myopia, myopic astigmatism, and hyperopia and identify ocular and lens parameters that might predict the vault amount.

SETTING

Fernández-Vega Ophthalmological Institute, Oviedo, Spain.

DESIGN

Cohort study.

METHODS

Three months after implantation of Implantable Collamer Lens pIOLs to correct myopia, hyperopia, and myopic astigmatism, central vault was measured using optical coherence tomography. Patients were divided into groups according to the preoperative anterior chamber depth (ACD) to compare the effects of ACD, white-to-white (WTW) distance, and lens diameter on postoperative pIOL vault.

RESULTS

Hyperopic pIOLs had statistically significantly lower vault followed by myopic pIOLs and toric pIOLs, which had a higher mean value and narrower range (260 to 860 μm). Measured vaults had a positive correlation with preoperative ACD (r = .32, P<.001) and WTW (r = .29, P<.001) and a negative correlation with preoperative spherical equivalent (SE) (r = -0.21, P<.001) and patient age (r = -0.12, P=.025). Eyes with a vault of 250 μm or less had a shallower ACD than eyes with a vault between 250 μm and 750 μm (mean difference -0.11 mm; P=.012) and those with a vault greater than 750 μm (mean difference -0.25 mm; P<.001).

CONCLUSIONS

Central vaulting was lower in hyperopic eyes. Current nomograms for pIOL diameter selection based on ACD and WTW might yield ideal vault and may have to be adjusted for older patients, shallower ACD, lower WTW, and lower SE.

Refractive lens exchange versus phakic intraocular lenses

PURPOSE OF REVIEW

To review the evidential basis of current practice in refractive lens exchange (RLE) vs. phakic intraocular lens (pIOL).

RECENT FINDINGS

Visual outcomes after pIOLs are better than RLE. With RLE, there still remain risks of retinal detachment, cystoid macular oedema, glare, halos and posterior capsule opacification. With pIOLs, risks include pigment dispersion, cataract formation, glaucoma and inflammation. The decision to choose between either is broadly based on age and type of refractive error, and the choice follows thorough evaluation and counselling taking into consideration patient's needs and expectations.

SUMMARY

With advancing technology, newer IOL models for RLE and phakic correction are becoming available. pIOLs provide better visual outcomes for distance correction and currently do not provide near-vision correction possible with RLE.

[Evaluation and quality assurance of refractive surgery procedures by the German Ophthalmological Society and the Professional Association of German Ophthalmologists. Status: May 2011]

The Commission of Refractive Surgery (KRC), which is a combined commission of the German Ophthalmological Society (DOG) and the Professional Association of German Ophthalmologists (BVA), has made an up-to-date evaluation of the operative techniques for correction of refraction errors. In the revised guidelines drawn up by the KRC for evaluation and safeguarding the quality of refractive surgical procedures the description, area of application, limitations, side-effects and complications of each procedure are given according to the published scientific literature. By this means a comprehensive explanation for and investigation of patients should be safeguarded, optimal treatment results achieved and complications avoided. In this article all relevant forms of refractive surgery (photorefractive keratectomy, LASEK, EPI-LASIK, LASIK, Femto-LASIK, RELEX, conductive keratoplasty, astigmatic keratotomy, limbal relaxing incisions, intracorneal ring segments, corneal cross-linking, phakic intraocular lenses, refractive lens exchange, corneal presbyopia implants, INTRACOR) are described in detail and quality guidelines are established. Refractive surgical care and additional medical services possibly arising prior to or following this treatment are not basically covered by the statutory health insurance (GKV).