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Clinical efficacy of femtosecond laser for myopia
摘要： Background: Femtosecond laser (FL) is an effective method to treat patients with myopia, but its relative efficacy and safety is still unclear. Thus, this study will be conducted to assess the efficacy and safety of FL for myopia systematically. Methods: This study will systematically retrieve the following electronic databases up to the present: Cochrane Library, PubMed, EMBASE, Web of Science, PsycINFO, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, Wanfang, VIP, and China National Knowledge Infrastructure. All electronic databases will be searched without any limitations of language and publication status. RevMan 5.3 software will be utilized for statistical analysis. Results: We will summarize the targeted results evaluating the efficacy and safety of FL for patients with myopia. Conclusions: This study will provide a comprehensive evidence summary on FL for patients with myopia.
关键词： femtosecond laser,efficacy,safety,myopia
更新于2025-09-11 14:15:04
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Visual Quality After Femtosecond Laser Small Incision Lenticule Extraction
摘要： Femtosecond laser small incision lenticule extraction (SMILE) is a newly developed form of “flapless” corneal refractive surgery with all-in-one technology. Femtosecond laser SMILE is increasingly attractive for both doctors and patients because it is minimally invasive and does not require a flap to be lifted during surgery. It exhibits many advantages in terms of morphology, biomechanical effects, corneal wound healing, and nerve rehabilitation. However, visual quality assessment after refractive surgeries is just as important as these advantages and correlates with patient satisfaction. Evaluation indexes for visual quality include visual acuity, contrast sensitivity, aberration, intraocular scattering, and so on. This paper reviewed visual quality and patient satisfaction after SMILE for myopia correction.
关键词： aberration,contrast sensitivity,lenticule extraction,myopia,femtosecond laser,scattering,small incision,visual quality
更新于2025-09-11 14:15:04
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The Association between Ocular Dominance and Refractive Errors in Chinese Myopic Subjects
摘要： Background: To determine the association between ocular dominance and myopic anisometropia in Chinese myopic subjects. This relevance would facilitate to identify the ocular dominance in bilateral cataract patients. Design: Retrospectively case study. Participants: 1503 Chinese myopic subjects, mean age 27 years, who were candidates for corneal myopic refractive surgery were reviewed between 2011 and 2012. Methods: The ocular dominance was determined by the hole-in-the-card test. The associations between ocular the sphere, cylinder, spherical and astigmatic laterality and refractive characters, including dominance anisometropia, were analyzed. Main outcome measures: Ocular dominance, manifest refraction, cycloplegic refraction. Results: 992 (66%) subjects were right-eye dominant while 511 (34%) subjects were left-eye dominant. The dominant eyes had lower spherical equivalents (SE) and cylinders than the non-dominant eyes (-5.36 D vs. -5.48 D and -0.70 D vs. -0.76 D, respectively, P<0.001). The ocular dominance was significantly associated with the lower myopic eye in subjects with SE anisometropia >0.5 D (P<0.05). There was also significant association between the dominant eyes and the lower astigmatic eyes in the subjects with astigmatic anisometropia > 0.25 D (P<0.05). In unilateral astigmatic subjects, non-astigmatic eyes were noted to be the dominant eyes in 111 (57.51%) subjects and astigmatic eyes represented dominance in 82 (42.49%) subjects. The difference was not statistically significant (P=0.249). The ocular dominance was not associated with the sex. Conclusion: In Chinese myopic subjects, the dominant eye usually had lower myopic SE and lower astigmatism compared with the non-dominant eye, especially in subjects with high amount of anisometropia.
关键词： Astigmatism,Ocular dominance,Cataract,Myopia
更新于2025-09-10 09:29:36
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The effect of the optical design of multifocal contact lenses on choroidal thickness
摘要： Studies have found reduced myopia progression with multifocal contact lenses, albeit with an unclear mechanism behind their protective effect. It is hypothesized that the induced myopic defocus of the addition zones of the multifocal contact lenses leads to choroidal thickening and therefore inhibits eye growth. In the current study, the effect of the optical design of multifocal contact lenses on choroidal thickness was investigated. Eighteen myopic participants wore four different contact lenses ((1) single-vision lenses corrected for distance, (2) single-vision lenses with +2.50 D full-field defocus, (3) Multifocal center-distance design, (4) Multifocal center-near design, both with addition power +2.50 D) for 30 min each on their right eye. Automated analysis of the macular choroidal thickness and vitreous chamber depth were performed before and after the wear of each of the contact lenses. Peripheral refraction profiles in primary gaze were obtained using eccentric photorefraction prior to contact lens wear. Choroidal thickness and vitreous chamber depth showed no significant differences to baseline with any of the contact lenses (all p > 0.05). Choroidal thickness increased by +2.1 ± 11.1 μm with the Multifocal center-distance design, by +2.0 ± 11.1 μm with the full-field defocus lens, followed by the Multifocal center-near design with +1.6 ± 11.3 μm and the single-vision contact lens correcting for distance with +0.9 ± 11.2 μm. Multifocal contact lenses have no significant influence on choroidal thickness after short-term wear. Therefore, changes in choroidal thickness might not be the main contributor to the protective effect of multifocal contact lenses in myopia control.
关键词： multifocal contact lenses,choroidal thickness,optical design,defocus,myopia control
更新于2025-09-10 09:29:36
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Posterior Eye Shape Measurement With Retinal OCT Compared to MRI
摘要： PURPOSE. Posterior eye shape assessment by magnetic resonance imaging (MRI) is used to study myopia. We tested the hypothesis that optical coherence tomography (OCT), as an alternative, could measure posterior eye shape similarly to MRI. METHODS. Macular spectral-domain OCT and brain MRI images previously acquired as part of the Singapore Epidemiology of Eye Diseases study were analyzed. The right eye in the MRI and OCT images was automatically segmented. Optical coherence tomography segmentations were corrected for optical and display distortions requiring biometry data. The segmentations were ?tted to spheres and ellipsoids to obtain the posterior eye radius of curvature (Rc) and asphericity (Qxz). The differences in Rc and Qxz measured by MRI and OCT were tested using paired t-tests. Categorical assignments of prolateness or oblateness using Qxz were compared. RESULTS. Fifty-two subjects (67.8 6 5.6 years old) with spherical equivalent refraction from t0.50 to (cid:2)5.38 were included. The mean paired difference between MRI and original OCT posterior eye Rc was 24.03 6 46.49 mm (P ? 0.0005). For corrected OCT images, the difference in Rc decreased to (cid:2)0.23 6 2.47 mm (P ? 0.51). The difference between MRI and OCT asphericity, Qxz, was (cid:2)0.052 6 0.343 (P ? 0.28). However, categorical agreement was only moderate (j ? 0.50). CONCLUSIONS. Distortion-corrected OCT measurements of Rc and Qxz were not statistically signi?cantly different from MRI, although the moderate categorical agreement suggests that individual differences remained. This study provides evidence that with distortion correction, noninvasive of?ce-based OCT could potentially be used instead of MRI for the study of posterior eye shape.
关键词： asphericity,optical coherence tomography,magnetic resonance imaging,myopia
更新于2025-09-10 09:29:36
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Caveats to Obtaining Retinal Topography With Optical Coherence Tomography
摘要： We read with great interest the article by Oh et al.1 on the assessment of retinal topography in myopic eyes using spectral domain optical coherence tomography (SD-OCT). In their article, the investigators described different characteristics of retinal topography to indicate variations in ocular shape in myopia (such as a retina sloped nasally versus temporally). Like similar prior studies using magnetic resonance imaging (MRI) to measure posterior eye shape in myopia, we agree this work in retinal topography provides important insight into classifying and risk stratifying myopic eyes. However, we would like to highlight a misconception regarding the use of posterior segment SD-OCT images for absolute retinal topography measurements. In the Discussion section, it is stated that 'The rainbow pseudo-colors in the topographic (RPE) layer image represent height from the coronal plane of the eye, with blue indicating low height and red indicating high height.' In OCT, the reference plane is not the coronal plane or any plane within the eye. Instead, the reference plane is a reference delay path length in the OCT device itself.2 Axial distance (height) within an OCT image represents sample distances relative to that reference delay in optical path length. Therefore, because the reference is in the OCT device and not in the eye itself, how the eye is positioned relative to the OCT device affects the eye’s appearance in the OCT image. For example, all three distinct subtypes of retinal sloping described in the article (nasal, middle, and temporal) can be produced from the same eye simply by moving the OCT scan beam position in the pupil slightly relative to the pupil center (see Figure). The same effect also would occur if, conversely, the subject’s eye moved relative to the OCT device. Further, OCT images of the posterior eye are distorted by scan geometry and optical artifacts as our group and others have described previously.3–5 The cumulative effect is that an OCT image of the posterior eye is not an exact spatial replica or digital 'cast' of the eye itself. Hence, when using OCT to measure the absolute topography of the posterior eye, these imaging effects must be considered to separate them from actual topographic differences present in these myopic eyes.
关键词： retinal topography,posterior eye shape,myopia,optical coherence tomography,imaging artifacts
更新于2025-09-09 09:28:46
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Outcomes of Small Incision Lenticule Extraction: Mild to Moderate Myopia versus High Myopia
摘要： Purpose: To evaluate the refractive outcomes of small incision lenticule extraction (SMILE) in high myopia patients compared with mild to moderate myopia patients. Methods: This study included 332 eyes of 166 myopic patients treated with SMILE using Visumax 500 kHz femtosecond laser. Treated eyes were divided into 2 groups according to preoperative spherical equivalent (SE): mild to moderate myopia (A group, <-6.0 D) and high myopia (B group, ≥-6.0 D). Follow-up visits were at 1 day, 1 week, 1 month, 3 months, and 6 months. The outcome measures included uncorrected distance visual acuity (UDVA), best corrected distance visual acuity (BDVA), postoperative SE, efficacy index, safety index and predictability. Results: Preoperative SE was -4.85 ± 0.86 D in the A group and -7.70 ± 1.0 D in the B group. No differences were observed between -0.04 ± 0.29 D in the A group and -0.30 ± 0.37 D in the B group at 6 months postoperatively (p = 0.062). At 6 months postoperatively, 98.3% and 97.3% had UDVA of 20/25 or better in the A group and B group, respectively. In the A group, 97.3% and 100% were within ±0.5 D and ±1.0 D of intended correction and in the B group, 91.7% and 96.9% were within ±0.5 D and ±1.0 D, respectively. Efficacy indices were 1.02 ± 0.19 in the A group and 0.99 ± 0.18 in the B group. Safety indices were 1.16 ± 0.16 in the A group and 1.14 ± 0.16 in the B group. The efficacy and safety indices were not significantly different between the A and B groups at 6 months postoperatively (p = 0.09, p = 0.695, respectively). Conclusions: This study showed that SMILE is effective and safe for correcting high myopia as well as mild to moderate myopia.
关键词： Best corrected distance visual acuity,SMILE,High myopia,Uncorrected distance visual acuity
更新于2025-09-09 09:28:46
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Opposing Effects of PPARα Agonism and Antagonism on Refractive Development and Form Deprivation Myopia in Guinea Pigs
摘要： PURPOSE. To determine if drug-induced peroxisome proliferator-activated receptor a (PPARa) signal pathway modulation affects refractive development and myopia in guinea pigs. METHODS. Pigmented guinea pigs were randomly divided into normal vision (unoccluded) and form deprivation myopia (FDM) groups. Each group received daily peribulbar injections of either a vehicle or (1) PPARa agonist, GW7647, clo?brate, or beza?brate or (2) PPARa antagonist, GW6471, for 4 weeks. Baseline and posttreatment refraction and ocular biometric parameters were measured. Immuno?uorescent staining of PPARa and two of its downstream readouts, cytosolic malic enzyme 1 (ME1) and apolipoproteinA II (apoA-II), was undertaken in selected scleral sections. Western blot analysis determined collagen type I expression levels. RESULTS. GW6471 induced a myopic shift in unoccluded eyes, but had no effect on form-deprived eyes. Conversely, GW7647 inhibited FDM progression without altering unoccluded eyes. Beza?brate and clo?brate had effects on refraction similar to those of GW7647 in unoccluded and form-deprived eyes. GW6471 downregulated collagen type I expression in unoccluded eyes whereas beza?brate inhibited collagen type I decreases in form-deprived eyes. GW6471 also reduced the density of ME1- and apoA-II–stained cells in unoccluded eyes whereas beza?brate increased apoA-II–positive cell numbers in form-deprived eyes. CONCLUSIONS. As GW7647 and GW6471 had opposing effects on myopia development, PPARa signaling modulation may be involved in this condition in guinea pigs. Fibrates are potential candidates for treating myopia since they reduced both FDM and the associated axial elongation. Beza?brate also inhibited form deprivation–induced decreases in scleral collagen type I expression and the density of apoA-II expressing cells.
关键词： apoA-II,ME1,myopia,GW6471,guinea pig,fibrates,PPARa,GW7647
更新于2025-09-04 15:30:14
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Off-Label Use of Phakic Intraocular Lens with a “Piggyback” Technique
摘要： Purpose: We report a case of a highly myopic pseudophakic patient who received off-label placement of a phakic intraocular lens (pIOL) via a “piggyback” technique, allowing the placement of an intraocular lens (IOL) in his fellow eye, resulting in improved visual acuity and emmetropia. Case Report: A 66-year-old, highly myopic, pseudophakic male with an IOL implant in his left eye was referred for second opinion for surgical options for his phakic right eye. Given the severe myopic status of both eyes, he received off-label placement of a posterior chamber pIOL with a piggyback technique for the pseudophakic left eye followed by standard cataract surgery and intraocular lens implantation in the right eye. For the left eye, uncorrected best visual acuity improved from 20/70 to 20/25. Conclusion: This case demonstrates the successful off-label use of a phakic IOL in a pseudophakic, highly myopic patient with a piggyback technique, resulting in improved visual acuity and ultimately allowing IOL placement in the fellow eye for emmetropia. This off-label use of pIOL can offer ophthalmologists an alternative option for pseudophakic patents with severe refractive error.
关键词： Cataract surgery,Piggyback technique,Refractive error,High myopia,Phakic intraocular lens
更新于2025-09-04 15:30:14
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The repeatability of superficial retinal vessel density measurements in eyes with long axial length using optical coherence tomography angiography
摘要： Background: To investigate the repeatability of superficial retinal vessel density measurements in healthy eyes with long axial length (AL) using optical coherence tomography angiography (OCTA). Methods: There were 60 eyes of 31 volunteers enrolled in this cross-sectional observational study. All subjects underwent OCTA, AL and refraction test. The enrolled eyes were divided into the long AL group (26 mm ≤ AL < 28 mm) and normal AL group (22 mm ≤ AL < 26 mm). The vessel length density (VLD), perfusion density (PD), and fovea avascular zone (FAZ) of the superficial retinal vessel were evaluated. Repeatability was assessed by intraclass correlation coefficients (ICCs) and Bland-Altman analysis. Pearson’s r correlation was used to analyze the relation of AL and the absolute difference between two measurements. Results: The 3 × 3 mm scan pattern showed good repeatability with all ICCs over 0.7. For all parameters of all scan patterns, the ICCs of the normal AL group were distinctly higher than those of the long AL group; this finding was also confirmed by Bland-Altman analysis. The correlation analysis of AL and repeatability of OCTA parameters showed significant negative correlations between the ALs and repeatability of VLD in 6 × 6 mm inner ring (r2 = 0.13, p = 0.01), VLD in 6 × 6 mm outer ring (r2 = 0.09, p = 0.02) and PD in 6 × 6 mm outer ring (r2 = 0.08, p = 0.03). Conclusions: The AL and the scanned area will both affect the repeatability of superficial retinal vessel density measurements in OCTA.
关键词： Fovea avascular zone,Vessel length density,Myopia,Optical coherence tomography angiography,Repeatability,Perfusion density
更新于2025-09-04 15:30:14