Corneal inlays for presbyopia correction.

PURPOSE OF REVIEW: This study provides an overview of the three types of corneal inlays now in use for the correction of presbyopia and reviews recently published evidence of the inlays' safety and efficacy. RECENT FINDINGS: Results for corneal reshaping and refractive inlays are promising, but very limited. Small-aperture inlays are already in widespread use and have been shown to improve uncorrected near and intermediate vision without a significant loss in distance acuity or an unacceptable increase in visual symptoms. Complications have been minimal, but the inlays may be removed if necessary. They do not prevent visualization or imaging of the retina and may be retained during subsequent cataract surgery. SUMMARY: The presbyopic demographic is large and growing, with a high level of interest in spectacle independence. There is currently no other effective solutions for presbyopes who desire good uncorrected vision at all distances without the risks of intraocular surgery or the visual compromises of monovision. Additional research is needed, but the future for corneal inlay technology is bright.

Aspheric wavefront-guided versus wavefront-guided LASIK for myopic astigmatism with the Technolas 217z100 excimer laser.

PURPOSE: To compare clinical outcomes of wavefront-guided LASIK with and without aspheric compensation in myopic eyes. METHODS: In this observational, single-center study, 134 eyes were treated using an aspheric module in combination with wavefront-guided profiles (PTA-algorithm) and compared to 146 eyes treated with the predecessor wavefront-guided software (APT) that has no aspheric compensation. All treatment plans included the Rochester nomogram that accounts for the preoperative manifest refraction and interaction of higher order aberrations. Active eye-tracking (including cyclorotational movements) was utilized during photoablation. RESULTS: Results at the 3-month follow-up: 67 % of PTA-treated eyes and 39 % of APT-treated eyes achieved an uncorrected distance visual acuity (UDVA) of 20/20 or better. Change in mean higher order aberration root-mean-square (HOA RMS) after PTA treatments was not statistically significant (p = 0.18). The increase in HOA RMS after APT treatments was statistically significant (p = 0.003). Change in mean postop spherical aberration (SA) after PTA treatments was not statistically significant (p = 0.27). The change in SA after APT treatments was statistically significant (p = 0.001). In both cohorts, mean uncorrected low-contrast visual acuity was statistically not different to preoperative corrected values. CONCLUSIONS: Adding an aspheric compensation to wavefront-guided myopic LASIK statistically improved clinical results in terms of visual acuity and refractive outcomes. Low-contrast visual acuity was not negatively affected in either group. While in APT-treated eyes mean HOA RMS and mean SA were significantly increased postoperatively, PTA-treated eyes showed neither induced HOA RMS nor induced SA.

Higher-order aberrations after implantation of iris-fixated rigid or foldable phakic intraocular lenses.

PURPOSE: To evaluate higher-order aberrations (HOAs) after implantation of Artiflex phakic intraocular lenses (pIOLs). SETTING: Department of Ophthalmology, Academic Hospital Maastricht, Maastricht, The Netherlands. METHODS: This retrospective comparative case series comprised 27 eyes (14 patients) that had Artiflex pIOL implantation and 22 eyes (13 patients) that had Artisan pIOL implantation. Refractive data, pupil size, IOL decentration, and HOA values were recorded and compared. Laboratory analysis was performed. Follow-up was 1 year. RESULTS: In the Artiflex group, the mean spherical equivalent (SE) changed from -9.95 diopters (D) +/- 1.43 (SD) (range -6.75 to -12.13 D) to -0.30 +/- 0.53 D (range -1.94 to 0.56 D). Postoperatively, trefoil-y increased (increase factor 1.73) and spherical aberration decreased (increase factor 0.55). The mean pIOL decentration was 0.24 +/- 0.12 mm; 96.3% were decentered 0.5 mm or less. There was a significant correlation between pIOL decentration and postoperative spherical aberration and coma-y. In the Artisan group, the mean SE changed from -9.90 +/- 2.74 D (range -4.00 to -14.50 D) to -0.20 +/- 0.42 D (range -0.75 to 0.50 D). Postoperatively, trefoil-y and spherical aberration increased (increase factors 3.32 and 6.84, respectively). Laboratory analysis confirmed the negative and positive spherical aberration profile of the Artiflex pIOL and Artisan pIOL, respectively. CONCLUSIONS: Artiflex pIOL implantation decreased spherical aberration, while Artisan pIOL implantation increased spherical aberration. Trefoil-y increased in both groups. These changes might be explained by incision size differences in relation to trefoil and differences in optic design in relation to spherical aberration.

Customized LASIK treatment for myopia based on preoperative manifest refraction and higher order aberrometry: the Rochester nomogram.

PURPOSE: To develop and test the efficacy of myopic treatment, based on preoperative manifest refraction and higher order aberrations, in enhancing the postoperative refractive error following customized LASIK treatment and compare results with the manufacturer-recommended sphere offset Zyoptix treatment nomogram, which does not account for the preoperative higher order aberrations. METHODS: One hundred seventy-five myopic eyes (89 patients) were treated based on the Rochester nomogram, which specified the amount of myopia to be treated based on preoperative manifest refraction and higher order aberrations, including third order aberrations and spherical aberration. Postoperative refractive error was measured at 1 month and compared to that theoretically estimated with the Zyoptix nomogram. RESULTS: The mean preoperative sphere and cylinder were -4.52 +/- 2.05 diopters (D) and -0.81 +/- 0.70 D, respectively. The mean postoperative spheres were +0.04 +/- 0.33 D and +0.31 +/- 0.54 D, using the Rochester and Zyoptix nomograms, respectively. The mean postoperative spherical equivalent refractions were -0.11 +/- 0.34 D and +0.15 +/- 0.53 D using the Rochester and Zyoptix nomograms, respectively. The Rochester nomogram reduced the range of postoperative spherical equivalent to +/- 1.00 D, which was significantly better than that using the Zyoptix nomogram (t = 5.46, P < .0001), which would have resulted in 8% of eyes with a postoperative spherical equivalent refraction > +/- 1.00 D. Using the Rochester nomogram, 93.1% of eyes attained a postoperative UCVA > or = 20/20. The percentage of postoperative hyperopic overcorrection decreased to 2.8% in the Rochester nomogram group from 22.3% using the Zyoptix nomogram, which only adjusts spherical values based on preoperative sphere and does not account for preoperative aberrations. CONCLUSIONS: The Rochester nomogram compensates for the effect of preoperative higher order aberrations on sphere and provided reduced range of postoperative spherical equivalent refraction.

Does dilated wavefront aberration measurement provide better postoperative outcome after custom LASIK?

PURPOSE: To compare outcomes after custom LASIK based on non-pharmacologically dilated (natural mesopic pupil) and pharmacologically dilated wavefront aberration measurement. DESIGN: Case-control study. PARTICIPANTS AND CONTROLS: The study group included 81 myopic eyes from 81 patients (mean preoperative spherical equivalent [SE], -4.15+/-1.97 diopters [D]). The control group consisted of 87 myopic eyes from 87 patients (mean preoperative SE, -4.98+/-2.00 D). METHODS: The 81-eye study cohort was treated based on nonpharmacological low mesopic dilated wavefront aberration measurement (Zywave aberrometer), and the postoperative outcome was compared with that of the control group of 87 eyes treated, based on pharmacologically dilated (2.5% neosynephrine) wavefront data, using the Zyoptix platform. The same nomogram was used for both groups, which adjusts sphere based on the amount of preoperative higher-order aberration. All eyes had a low mesopic pupil diameter of > or =6.3 mm without pharmaceutical intervention. MAIN OUTCOME MEASURE: Postoperative 3-month visual acuity (VA), contrast sensitivity, and refractive error. RESULTS: Of the non-pharmacologically dilated eyes (study) and pharmacologically dilated (control) eyes, 96.3% and 96.6%, respectively, attained postoperative uncorrected VA of 20/20 or better. Although 96.6% of the eyes were within the target SE of +/-0.50 D in the control group, 100% of the 81 study eyes were within an SE of +/-0.50 D postoperatively. The range of postoperative SE (-0.75 to +1 D) was slightly reduced among the study eyes (+/-0.50 D). Differences were not statistically significant. CONCLUSIONS: When a low mesopic pupil dilates to > or =6.3 mm, pharmacological dilation with wavefront-guided ablation may provide no additional benefit with regard to spherical accuracy when compared with nonpharmacological wavefront-guided ablation. The use of the Rochester nomogram, which accounts for aberration interaction, provided excellent results with or without pharmacological dilation.

Effect of beam size on the expected benefit of customized laser refractive surgery.

PURPOSE: Customized laser surgery attempts to correct higher order aberrations, as well as defocus and astigmatism. The success of such a procedure depends on using a laser beam that is small enough to produce fine ablation profiles needed to correct higher order aberrations. METHODS: Wave aberrations were obtained from a population of 109 normal eyes and 4 keratoconic eyes using a Shack-Hartmann wavefront sensor. We considered a theoretical customized ablation in each eye, performed with beams of 0.5, 1.0, 1.5, and 2.0 mm in diameter. We then calculated the residual aberrations remaining in the eye for the different beam sizes. Retinal image quality was estimated by means of the modulation transfer function (MTF), computed from the residual aberrations. Fourier analysis was used to study spatial filtering of each beam size. RESULTS: The laser beam acts like a spatial filter, smoothing the finest features in the ablation profile. The quality of the correction declines steadily when the beam size increases. A beam of 2 mm is capable of correcting defocus and astigmatism. Beam diameters of 1 mm or less may effectively correct aberrations up to fifth order. CONCLUSION: Large diameter laser beams decrease the ability to correct higher order aberrations. A top-hat laser beam of 1 mm (Gaussian with FWHM of 0.76 mm) is small enough to produce a customized ablation for typical human eyes.

Treatment of interface keratitis with oral corticosteroids.

PURPOSE: To describe the results of treating interface keratitis using a combination of intensive topical and oral corticosteroids. SETTING: Casey Eye Institute, Portland, Oregon, USA. METHODS: Thirteen eyes treated for grade 2 to 3 interface keratitis using an oral corticosteroid (prednisone 60 to 80 mg) as well as an hourly topical corticosteroid were retrospectively reviewed. The best corrected visual acuity (BCVA) was used as an objective guide of whether to treat with intense topical and oral corticosteroids, flap irrigation, or both. Predisposing factors such as intraoperative epithelial defects or a history of severe allergies or atopy were also looked for. RESULTS: All 13 eyes responded favorably to the combination of intensive topical and oral corticosteroids and had a BCVA of 20/20 after the keratitis resolved. In 6 eyes (46%), the patients had a history of severe seasonal allergies. One day postoperatively, 3 eyes (23%) had an epithelial defect and 2 eyes (15%), lint particles or debris embedded in the interface. With oral corticosteroid use, 3 patients (23%) noted mild stomach irritation and 2 (15%) noted nervousness. All 5 side effects resolved without sequelae. No patient developed a serious side effect. CONCLUSIONS: A short, intense course of an oral corticosteroid was an effective treatment in patients with grade 2 or higher interface keratitis when combined with a topical corticosteroid administered hourly. The BCVA is a helpful objective measure of the severity of interface keratitis and can be used to guide the clinician in the therapeutic strategy.