Kimiya Shimizu

Toric intraocular lenses: Correcting astigmatism while controlling axis shift

Abstract We evaluated the efficacy of toric intraocular lenses (IOLs) implanted in the eyes of 47 patients who had preoperative against‐the‐rule astigmatism. The lenses, which had a cylinder power of 2.00 diopters (D) (n = 26) or 3.00 D (n = 21), were implanted through a 5.7 mm incision after cataract extraction by phacoemulsification. Best corrected visual acuity three months postoperatively was 20/25 or better in 77% of eyes. The 3.00 D IOLs resulted in better correction than the 2.00 D IOLs when the axis shift of the lens was less than 30 degrees. A negative effect occurred in some eyes in which the lens axis rotated more than 30 degrees. The maximum acceptable axis shift seems to be less than 30 degrees.

Repeatability, reproducibility, and agreement characteristics of rotating Scheimpflug photography and scanning-slit corneal topography for corneal power measurement

PURPOSE: To evaluate the repeatability, reproducibility, and agreement in anterior, posterior, and in particular the total corneal power of 2 topography devices, rotating Scheimpflug photography and scanning‐slit topography. SETTING: Department of Ophthalmology and Visual Science, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan. METHODS: Seventeen eyes of 17 subjects (mean age 24.7 years ± 4.1 [SD]) were included in the study. The corneal shapes within the central 3.0 mm were measured with rotating Scheimpflug photography (Pentacam) and scanning‐slit corneal topography (Orbscan II). The within‐rater repeatability and reproducibility of 2 raters and the overall between‐instrument agreement of the measurements were evaluated using intraclass correlation coefficients (ICCs) and the Bland‐Altman method. RESULTS: The repeatability of Scheimpflug photography and scanning‐slit corneal topography was high (ICC, 0.70 to 0.99). Scheimpflug photography outperformed scanning‐slit corneal topography for anterior power, posterior power, and total corneal power. The reproducibility results were similar, with limits of agreement (LoA) consistently narrower for Scheimpflug photography. The between‐instrument agreement was moderate, with LoA around the mean value of total corneal power of 0.46 diopter ranging from 0.032 to 0.889. CONCLUSIONS: The results suggest that repeatability and reproducibility are higher in Scheimpflug photography than in scanning‐slit topography. The agreement between rotating Scheimpflug photography and scanning‐slit topography for total corneal power was moderate.

Four-year follow-up of posterior chamber phakic intraocular lens implantation for moderate to high myopia.

OBJECTIVE To assess the long-term clinical outcomes of implantation of a lens consisting of a biocompatible collagen copolymer (Visian implantable Collamer lens [ICL]; STAAR Surgical, Nidau, Switzerland) for moderate to high myopia. METHODS We evaluated 56 eyes of 34 patients with myopic refractive errors of -4.00 to -15.25 diopters (D) who underwent ICL implantation and routine postoperative examinations. Before and 1, 3, and 6 months and 1, 2, and 4 years after surgery, we assessed the safety, efficacy, predictability, stability, and adverse events of the surgery. RESULTS Mean (SD) logMAR uncorrected and best spectacle-corrected visual acuities were -0.03 (0.23) and -0.21 (0.09), respectively, at 4 years after surgery. The mean (SD) safety and efficacy indexes were 1.19 (0.25) and 0.83 (0.29), respectively. At 4 years, 44 (79%) and 52 (93%) of the eyes were within +/-0.5 and +/-1.0 D, respectively, of the targeted correction. Mean (SD) manifest refraction changes of -0.24 (0.57) D occurred from 1 month to 4 years after surgery. No vision-threatening complications occurred during the observation period. CONCLUSION Implantation of ICLs is safe and effective and provides predictable and stable refractive results in the treatment of moderate to high myopia during a 4-year observation period, suggesting its viability as a surgical option for the treatment of such eyes.

Effect of Aging on Corneal Biomechanical Parameters Using the Ocular Response Analyzer

PURPOSE To assess the effect of aging on corneal biomechanical parameters in a normal population. METHODS We prospectively examined 204 normal eyes of 204 healthy Japanese volunteers (68 men, 136 women; mean age 46.7+/-19.4 years [range: 19 to 89 years]). Corneal hysteresis, corneal resistance factor, corneal-compensated intraocular pressure (IOP(cc)), and Goldmann-correlated intraocular pressure (IOP(G)) were qualitatively assessed using a Reichert Ocular Response Analyzer. Central corneal thickness was measured using an ultrasound pachymeter. This measurement was performed 3 times, and the mean value obtained was used for statistical analysis. The relationships between patient age and corneal biomechanical parameters, or age and intraocular pressure (IOP), were investigated. RESULTS Mean corneal hysteresis and corneal resistance factor were 10.1+/-1.5 mmHg and 10.1+/-1.6 mmHg, respectively. Mean central corneal thickness was 539.1+/-30.9 microm. A weak, but significant, negative correlation was found between age and corneal hysteresis (Pearsons correlation coefficient r=-0.17, P=.02) and corneal resistance factor (r=-0.18 P=.01). On the other hand, no significant correlation was found between age and central corneal thickness (r=-0.06, P=.41), age and IOP(cc) (r=-0.02, P=.82), or age and IOP(G) (r=-0.11, P=.11). CONCLUSIONS Corneal biomechanical parameters are significantly decreased by aging without significant changes in central corneal thickness or IOP, suggesting that age-related structural changes resulting from collagen cross-linking may lead to a reduction of corneal biomechanical variables independent of central corneal thickness or IOP.

Visual and refractive outcomes of femtosecond lenticule extraction and small-incision lenticule extraction for myopia.

PURPOSE To compare the visual and refractive outcomes of femtosecond lenticule extraction (FLEx) and small-incision lenticule extraction (SMILE) in eyes with myopia. DESIGN Prospective, randomized, masked clinical trial with intraindividual comparison. METHODS This study evaluated 52 eyes of 26 consecutive patients with spherical equivalents of -4.19 ± 1.65 diopters (D) (mean ± standard deviation) who underwent FLEx in 1 eye and SMILE in the other eye by randomized assignment. Before surgery, and 1 week and 1, 3, and 6 months after surgery, we assessed safety, efficacy, predictability, stability, and adverse events of the 2 surgical techniques. RESULTS LogMAR uncorrected and corrected distance visual acuity was, respectively, -0.17 ± 0.10, -0.20 ± 0.07 in the FLEx group and -0.15 ± 0.10, -0.19 ± 0.07 in the SMILE group 6 months postoperatively. In the FLEx and SMILE groups 6 months postoperatively, 96% and 100% of eyes, respectively, were within 0.5 D of the targeted spherical equivalent correction. Changes of -0.02 ± 0.39 D and 0.00 ± 0.30 D occurred in manifest refraction from 1 week to 6 months in the FLEx and SMILE groups, respectively. No clinically significant complications occurred in the FLEx or the SMILE group. CONCLUSIONS Both FLEx and SMILE performed well in the correction of myopia throughout the 6-month observation period. FLEx may be essentially equivalent to SMILE in terms of safety, efficacy, predictability, and stability, suggesting that the presence or absence of lifting the flap does not significantly affect these visual and refractive outcomes.

Comparison of the changes in corneal biomechanical properties after photorefractive keratectomy and laser in situ keratomileusis.

Purpose: To compare the postoperative biomechanical properties of the cornea after photorefractive keratectomy (PRK) and after laser in situ keratomileusis (LASIK) in eyes with myopia. Methods: We retrospectively examined 27 eyes of 16 patients undergoing PRK and 31 eyes of 16 patients undergoing LASIK for the correction of myopia. Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured with Ocular Response Analyzer before and 3 months after surgery. We also investigated the relationship between these biomechanical changes and the amount of myopic correction. Results: The CH was decreased significantly from 10.8 ± 1.3 (mean ± SD) mmHg to 9.2 ± 1.6 mmHg after PRK (P < 0.001), and from 10.8 ± 1.4 mmHg to 8.6 ± 0.9 mmHg after LASIK (P < 0.001). The CRF was also decreased significantly, from 10.3 ± 1.5 mmHg to 8.4 ± 1.8 mmHg after PRK (P < 0.001), and from 10.3 ± 1.5 mmHg to 7.7 ± 1.3 mmHg after LASIK (P < 0.001). The amount of decrease in CH and CRF was significantly larger after LASIK than after PRK (P = 0.04). There was a significant correlation between the amount of myopic correction and changes in biomechanical properties after PRK (r = −0.61, P < 0.01 for CH, r = −0.41, P < 0.05 for CRF) and LASIK (r = −0.37, P < 0.05 for CH, r = −0.45, P < 0.05 for CRF). Conclusions: Both PRK and LASIK can affect the biomechanical strength of the cornea depending on the amount of myopic correction. The amount of biomechanical changes is larger after LASIK than after PRK. From a biomechanical viewpoint, PRK may be a less invasive surgical approach for the correction of myopia than LASIK.

Comparison of Collamer toric contact lens implantation and wavefront-guided laser in situ keratomileusis for high myopic astigmatism

PURPOSE: To compare the postoperative visual outcomes after implantation of a Collamer toric implantable contact lens (ICL) and after wavefront‐guided laser in situ keratomileusis in high myopic astigmatism. SETTING: Department of Ophthalmology, Kitasato University, Kanagawa, Japan. METHODS: This study comprised 30 eyes (18 patients) having toric ICL implantation and 24 eyes (17 patients) having wavefront‐guided LASIK (Technolas 217z) to correct high myopic astigmatism (manifest spherical equivalent [SE] ≤−6.0 diopters [D]; manifest refractive cylinder ≥1.0 D). The safety, efficacy, predictability, stability, and adverse events were assessed preoperatively and 1 week and 1, 3, and 6 months postoperatively. RESULTS: At 6 months, the mean safety index was 1.28 ± 0.25 (SD) in the ICL group and 1.01 ± 0.16 in the LASIK group and the mean efficacy index, 0.87 ± 0.15 and 0.83 ± 0.23, respectively. All eyes in the ICL group and 71% of eyes in the LASIK group were within ±1.00 D of the targeted SE correction at 6 months. The mean change in manifest refraction from 1 week to 6 months was −0.04 ± 0.24 D in the ICL group and −0.60 ± 0.49 D in the LASIK group. There were no significant complications in the ICL group; 2 eyes (8.3%) in the LASIK group required enhancement ablations. CONCLUSION: Toric ICL implantation was better than wavefront‐guided LASIK in eyes with high myopic astigmatism in almost all measures of safety, efficacy, predictability, and stability, suggesting that toric ICL implantation may become a viable surgical option to treat high myopic astigmatism.

Effects of dominant and nondominant eyes in binocular rivalry.

Purpose. To investigate the relation between sighting and sensory eye dominance and attempt to quantitatively examine eye dominance using a balance technique based on binocular rivalry. Methods. The durations of exclusive visibility of the dominant and nondominant eye target in binocular rivalry were measured in 14 subjects. The dominant eye was determined by using the hole-in-card test (sighting dominance). In study 1, contrast of the target in one eye was fixed at 100% and contrast of the target in the other eye was varied from 100% to 80% to 60% to 40% to 20%, when using rectangular gratings of 1, 2, and 4 cycles per degree (cpd) at 2°, 4°, and 8° in size. In study 2, contrast of the target in the nondominant eye was fixed at 100% and contrast of the target in the dominant eye was varied from 100% to 80% to 60% to 40% to 20%, when using a rectangular grating of 2 cpd at 4° in size. Results. In study 1, the total duration of exclusive visibilities of the dominant eye target; that is, the target seen by the eye that had sighting dominance was longer compared with that of the nondominant eye target. When using rectangular gratings of 4 cpd, mean total duration of exclusive visibility of the dominant eye target was statistically longer than that of the nondominant eye target (p < 0.05). In study 2, reversals (in which duration of exclusive visibility of the nondominant eye becomes longer than the dominant eye when the contrast of the dominant eye target is decreased) were observed for all contrasts except for 100%. Conclusions. The dominant sighting eye identified by the hole-in-card test coincided with the dominant eye as determined by binocular rivalry. The contrast at which reversal occurs indicates the balance point of dominance and seems to be a useful quantitative indicator of eye dominance to clinical applications.

Clinical evaluation of the additive effect of diquafosol tetrasodium on sodium hyaluronate monotherapy in patients with dry eye syndrome: a prospective, randomized, multicenter study.

PurposeTo assess the additive effect of diquafosol tetrasodium on sodium hyaluronate monotherapy in patients with dry eye syndrome.MethodsThis study evaluated 64 eyes of 32 patients (age: 62.6±12.8 years (mean±SD)) in whom treatment with 0.1% sodium hyaluronate was insufficiently responsive. The eyes were randomly assigned to one of the two regimens in each patient: topical administration of sodium hyaluronate and diquafosol tetrasodium in one eye, and that of sodium hyaluronate in the other. Before treatment, and 2 and 4 weeks after treatment, we determined tear volume, tear film break-up time (BUT), fluorescein and rose bengal vital staining scores, subjective symptoms, and adverse events.ResultsWe found a significant improvement in BUT (P=0.049, Dunnett test), fluorescein and rose bengal staining scores (P=0.02), and in subjective symptoms (P=0.004 for dry eye sensation, P=0.02 for pain, and P=0.02 for foreign body sensation) 4 weeks after treatment in the diquafosol eyes. On the other hand, we found no significant change in these parameters after treatment in the control eyes.ConclusionsIn dry eyes, where sodium hyaluronate monotherapy was insufficient, diquafosol tetrasodium was effective in improving objective and subjective symptoms, suggesting its viability as an option for the additive treatment of such eyes.

Early clinical outcomes of implantation of posterior chamber phakic intraocular lens with a central hole (Hole ICL) for moderate to high myopia

Aim To assess the early clinical outcomes of an ICL with a central hole (Hole ICL) implantation for the correction of moderate to high myopia. Methods This study evaluated 20 eyes of 20 patients with spherical equivalents of −7.36±2.13 D (mean±SD) who underwent Hole ICL implantation. Before surgery and at 1 week and 1, 3 and 6 months after surgery, we assessed the safety, efficacy, predictability, stability and adverse events of the surgery. Results Logarithm of the minimum angle of resolution (logMAR) uncorrected visual acuity and logMAR best spectacle-corrected visual acuity were −0.20±0.12 and −0.25±0.06, respectively, 6 months after surgery. The safety and efficacy indices were 1.13±0.24 and 1.03±0.30, respectively. At 6 months, 95%, and 100% eyes were within ±0.5 and ±1.0 D of the targeted correction, respectively. Change in manifest refraction from week 1 to month 6 was 0.06±0.28 D. No significant rise in intraocular pressure (including pupillary block) or a secondary cataract occurred in any case during the period of observation. Conclusions Implantation of a newly developed Hole ICL offered good results for all measures of safety, efficacy, predictability and stability for the correction of moderate to high myopic errors, even without peripheral iridectomy, suggesting its viability as a surgical option for the treatment of such eyes.