Your browser doesn't support javascript.
loading
: 20 | 50 | 100
1 - 20 de 42
1.
Article En | MEDLINE | ID: mdl-38842594

PURPOSE: This study aimed to assess the optical quality of myopic and presbyopic IPCLs with different additional powers, and to investigate the effects of pupil size on the optical quality of these IPCLs using an in-vitro modulation transfer function (MTF) measurement system. METHODS: Linear scatter functions (LSFs) were recorded using the OPAL Vector system and an eye phantom consisting of wet cells filled with a balanced salt solution. A myopic IPCL or a presbyopic IPCL was placed in the posterior chamber of this model. The MTF was calculated from the LSF using the fast Fourier transform techniques. The effective apertures were set at 2.0 to 5.0 mm in 1.0 mm steps. RESULTS: The in-focus MTF values of the myopic IPCL and presbyopic IPCL with additional powers of + 2.0 and + 4.0 diopters at 100 cycles/mm for an effective aperture of 3.0 mm were 43%, 27%, and 24%, respectively. The in-focus MTF value of both myopic and presbyopic IPCLs was the highest when the effective aperture was set at 3.0 mm, and it gradually worsened when the effective aperture became larger than 3.0 mm at 20, 60, and 100 cycles/mm. CONCLUSIONS: Both myopic and presbyopic IPCLs provided excellent MTF values, but the additional power profile can deteriorate optical performance in presbyopic IPCL-implanted eyes, even with a low additional power. Pupil size can influence visual quality in IPCL-implanted eyes for both myopia and presbyopia.

2.
J Opt Soc Am A Opt Image Sci Vis ; 41(4): 581-587, 2024 Apr 01.
Article En | MEDLINE | ID: mdl-38568658

This study investigates the just-noticeable difference (JND) in luminance below the 0.050c d/m 2 threshold not covered by the DICOM standard in medical imaging displays. A total of 21 healthy young adults were tested using an ultralow-luminance liquid crystal display at a viewing distance of 46 cm. The optotype featured a 4 cycle/deg rectangular wave-like stripe. The average percentage of correct responses for JND indices between -18 and 0 was 70.8%. Using the extended JND based on the Barten model that matches the current JND definition, we confirmed the JND at a very low luminance of 0.0500c d/m 2 or less. These findings suggest the feasibility of further refining the gradation differences in medical imaging displays.


Diagnostic Imaging , Young Adult , Humans , Differential Threshold
3.
Case Rep Ophthalmol ; 15(1): 78-83, 2024.
Article En | MEDLINE | ID: mdl-38288025

Introduction: Lacteocrumenasia is a relatively rare postoperative complication of cataract surgery. It is classified as a late-onset type of capsular block syndrome (CBS) and is often accompanied by myopia; however, its mechanism is not clearly understood. Case Presentation: We report a case of a 62-year-old male patient having CBS with myopia. The patient was treated with neodymium-yttrium aluminum garnet (Nd-YAG) laser posterior capsulotomy. We measured and compared the depth of the intraocular lens using anterior segment optical coherence tomography (AS-OCT) before and after laser treatment. Treatment resulted in refraction improvement of more than 1.0 diopters. The intraocular lens depth before and after Nd-YAG laser irradiation had very mild changes of less than 0.05 mm, which did not explain the refractive changes. Conclusion: Myopia in the early-onset type of CBS is caused by anterior deviation of the intraocular lens; however, the evaluation of this case using AS-OCT suggested that an abnormal intraocular lens position may not be involved in late-onset CBS.

4.
Optom Vis Sci ; 100(12): 833-839, 2023 Dec 01.
Article En | MEDLINE | ID: mdl-38019964

SIGNIFICANCE: This study highlights the importance of twilight adaptation for reliable assessment of low-luminance visual acuity and understanding the relationship between low-luminance visual acuity and ocular aberrations. PURPOSE: The human eye experiences reduced visual acuity as luminance decreases owing to reduced retinal and optical resolutions; however, the details are unclear. This study aimed to quantify the effects of refraction, pupil diameter, and ocular aberrations on visual acuity during the transition from high- to low-light environments, thereby contributing to the standardization of low-luminance visual acuity measurements. METHODS: In total, 27 older participants with a mean age of 70.0 ± 4.1 years were included in this study. Visual acuity was measured according to the Early Treatment Diabetic Retinopathy Study (ETDRS) protocol with three luminance conditions: high luminance (300 cd/m 2 ), low luminance (10 cd/m 2 ), and low luminance with short-term (15-minute) twilight adaptation (10 cd/m 2 ). RESULTS: The mean logarithm of minimum angle of resolution values of visual acuity were -0.09 ± 0.09, 0.10 ± 0.13, and 0.03 ± 0.09 at 300, 10, and 10 cd/m 2 with twilight adaptation, respectively. Multiple regression analysis determined that spherical aberration ( P < .005) and tetrafoil ( P < .005) were significant factors associated with low-luminance visual acuity after twilight adaptation, with an adjusted R2 value of 0.35 for this model ( P < .005). CONCLUSIONS: Although the influence of ocular aberrations on low-luminance visual acuity may be relatively modest compared with neural effects, it remains a crucial factor that should not be overlooked. The absence of twilight (or dark) adaptation can cause ocular aberrations and neural effects, potentially leading to inaccuracies in the measurement of low-luminance visual acuity.


Refraction, Ocular , Vision Tests , Humans , Aged , Visual Acuity , Vision Disorders , Retina
5.
J Clin Med ; 12(15)2023 Aug 05.
Article En | MEDLINE | ID: mdl-37568536

BACKGROUND: We aimed to evaluate the existence of accommodative microfluctuations in eyes after cataract surgery. METHODS: This retrospective observational cohort study included 1160 eyes of 713 patients (mean age: 72.5 ± 8.3 years) who underwent phacoemulsification, intraocular lens insertion, and an evaluation of accommodative microfluctuations with an autorefractometer. Patients with posterior segment disorders resulting in visual acuity impairment and those with unavailable medical information were excluded. High-frequency components (HFCs), between 1.0-2.3 Hz, based on fast Fourier transform analysis of the accommodative microfluctuation data were examined at postoperative 2-3 (2 M) and 6 months (6 M). The relationships between the HFCs and patient age, manifest refraction, and axial length were analyzed. RESULTS: Increased HFC values (>65) were observed at a constant rate after cataract surgery, with prevalence rates of 33.4% at 2 M and 34.7% at 6 M. Postoperatively, at 2 M, increased HFC values were significantly more common for eyes with axial length ≥26 mm than for those with axial length <26 mm (p = 0.0056). However, they were not significantly correlated to age or postoperative manifest refraction. CONCLUSIONS: At 2 M postoperatively, increased HFC values presented more frequently in eyes with a greater axial length; hence, the precise detection and understanding of postoperative accommodative spasms in high myopia patients is important.

6.
J Opt Soc Am A Opt Image Sci Vis ; 40(5): 849-858, 2023 May 01.
Article En | MEDLINE | ID: mdl-37133182

We report normative cone contrast sensitivity values, right-left eye agreement, and sensitivity and specificity values for the cone contrast test-HD (CCT-HD). We included 100 phakic eyes with color vision normal (CVN) and 20 dichromatic eyes (10 with protanopia and 10 with deuteranopia). The CCT-HD was used to measure L, M, and S-CCT-HD scores, and the right and left eyes were evaluated for agreement using Lin's concordance correlation coefficient (CCC) and Bland-Altman analysis to investigate the sensitivity and specificity of the CCT-HD based on diagnosis with an anomaloscope device. All cone types were in moderate agreement with the CCC (L-cone: 0.92, 95% CI, 0.86-0.95; M-cone: 0.91, 95% CI, 0.84-0.94; S-cone: 0.93, 95% CI, 0.88-0.96), whereas the Bland-Altman plots showed that the majority of cases (L-cone: 94%; M-cone: 92%; S-cone: 92%) fell within the 95% limits of agreement and showed good agreement. The m e a n±s t a n d a r d error L, M, and S-CCT-HD scores for protanopia were 0.6±1.4, 74.7±2.7, and 94.6±2.4, respectively; for deuteranopia, these were 84.0±3.4, 40.8±3.3, and 93.0±5.8, respectively; and for age-matched CVN eyes (m e a n±s t a n d a r d deviation age, 53.1±5.8 years; age range, 45-64 years), these were 98.5±3.4, 94.8±3.8, and 92.3±3.4, respectively, with significant differences between the groups except for S-CCT-HD score (Bonferroni corrected α=0.0167, p<0.0167). The sensitivity and specificity of the CCT-HD were 100% for protan and deutan in diagnosing abnormal types in those aged 20 to 64 years; however, the specificity decreased to 65% for protan and 55% for deutan in those aged >65 years. The CCT-HD is comparable to the diagnostic performance of the anomaloscope in the 20-64-year-old age group. However, the results should be interpreted cautiously in those ≥65 years, as these patients are more susceptible to acquired color vision deficiencies due to yellowing of the crystalline lens and other factors.


Color Vision Defects , Color Vision , Humans , Middle Aged , Young Adult , Adult , Color Vision Defects/diagnosis , Color Perception Tests , Retinal Cone Photoreceptor Cells , Sensitivity and Specificity , Contrast Sensitivity
7.
PLoS One ; 17(9): e0274824, 2022.
Article En | MEDLINE | ID: mdl-36112725

This study aimed to investigate the visibility of colors in congenitally color vision defect people using general and fluorescent colors in an environment simulating sunset to examine the standards for high-visibility safety clothing for general users. Twenty participants with normal trichromats, seven protanopes, and five deuteranopes were included, with mean ages (± standard deviation) of 21.0±1.0, 46,7±16.1, and 56.6±6.9 years, respectively. Dyed fabrics were used to evaluate visibility. We evaluated brightness and conspicuousness sensitivity by combining red, yellow-red, yellow, green, red-purple, blue, white, black, fluorescent yellow, and fluorescent orange. For brightness sensitivity, the combination of fluorescent yellow and white/yellow stripes was highly visible and significantly different from all other samples (p < 0.05). For conspicuousness sensitivity, the combinations of black/fluorescent yellow, black/yellow, black/white, black/yellow-red, and white/red-purple stripes were highly visible and significantly different from all the other samples (p < 0.05). Yellow light is most visible and even better when fluorescent. They are based on specific spectral sensitivity, and yellow is the most visible, even for congenitally colorblind individuals. Furthermore, with regard to color combinations, it was found that the contrast between two distinct light or dark colors, such as black, yellow, black, and white, is perceived to be equally noticeable by congenital color vision defect individuals. This suggests the possible further applications of safety clothing.


Color Vision Defects , Color Perception , Humans
8.
PLoS One ; 17(7): e0271814, 2022.
Article En | MEDLINE | ID: mdl-35895708

This prospective observational study aimed to evaluate the ocular biometry of Japanese people through a multicenter approach. The uncorrected and corrected distance visual acuity (UDVA and CDVA, respectively) in the log minimum angle of resolution (logMAR), subjective and objective spherical equivalent values (SE) of ocular refraction, anterior and posterior corneal curvature (ACC and PCC, respectively), anterior and posterior corneal asphericity (ACA and PCA, respectively), central corneal thickness (CCT), anterior chamber depth (ACD), and ocular axial length (AL) were measured in the eyes of 250 participants (mean age = 46.5 ± 18.0 years, range: 20-90 years) across five institutions in Japan. The mean UDVA, CDVA, subjective SE, objective SE, ACC, PCC, ACA, PCA, CCT, ACD, and AL were 0.68, -0.08, -2.42 D, -2.66 D, 7.77 mm, 6.33 mm, -0.31, -0.39, 0.55 mm, 2.92 mm, and 24.78 mm, respectively. Age-related changes and sex-based differences were noted in the visual acuity, refraction, corneal shape, ACD, and AL. Our results serve as basis for future studies aiming to develop refractive correction methods and various vision-related fields.


Biometry , Refraction, Ocular , Adult , Cornea/diagnostic imaging , Humans , Japan , Middle Aged , Visual Acuity
9.
PLoS One ; 17(4): e0267149, 2022.
Article En | MEDLINE | ID: mdl-35427398

PURPOSE: We investigated the effect of luminance on refraction and visual function under twilight conditions. METHODS: Twenty young adults (mean age 20.5 ± 0.5 years) without ocular diseases and 20 eyes were included in the study. Subjective and objective spherical equivalent power (SE), logMAR, pupil diameter, ocular aberration, and ocular axial length were evaluated. Measurements were conducted in a light room with high luminance (300 cd/m2) targets (photopic), in a dark room with low luminance (10 cd/m2) targets (twilight), and a dark room after 15 min of adaptation to low luminance (10 cd/m2) targets (after adaptation: AA). Differences between the three conditions were analyzed using the Friedman test and Scheffe's multiple comparisons. RESULTS: The results of logMAR were -0.20 ± 0.07, -0.08 ± 0.08, and -0.11 ± 0.08 in photopic, twilight, and AA, respectively, with significant differences between photopic and twilight (p < 0.001) and between photopic and AA (p < 0.001). Then subjective SE were -3.58 ± 2.04 D, -3.75 ± 2.08 D, and -3.74 ± 2.04 D in photopic, twilight, and AA, respectively, with significant differences between photopic and twilight (p = 0.007) and photopic and AA (p = 0.023). However, none of the other objective SEs produced a significant difference (p = 0.63). The pupil diameter and ocular aberration changed significantly in all conditions (p < 0.001). CONCLUSIONS: Subjective myopic refraction increased and visual resolution decreased in younger subjects. However, this change in refraction is less than one level (±0.25 D) in clinical optometry, so fully corrected eyeglasses are important when assuming refraction in twilight, and there is no need for additional correction.


Color Vision , Myopia , Adult , Eyeglasses , Humans , Refraction, Ocular , Vision Tests , Young Adult
10.
Invest Ophthalmol Vis Sci ; 63(2): 22, 2022 02 01.
Article En | MEDLINE | ID: mdl-35147660

Purpose: To investigate the impact of the size and location of waterclefts (WC), which are one of several cataract subtypes, on visual function by optical simulation analysis. Methods: An optical simulation software (CODE V) was used to develop a schematic eye model and several sizes of WC central and peripheral types that were located below the anterior and posterior subcapsules of the crystalline lens, and analyses of refraction, higher-order aberrations (HOA), and the modulation transfer function (MTF) were performed. Results: An increase in the WC size increased the refraction and HOA and decreased the MTF. The impact of the WC below the posterior subcapsule on the visual function was more enhanced than that below the anterior subcapsule. Large WC demonstrated a remarkable hyperopic shift in refractive power as well as an increase in HOA. The MTF decreased slightly with increasing WC size at a spatial frequency of 20 cycles/mm, and it decreased remarkably at 60 cycles/mm. Conclusions: The impact on the visual function increased with increasing WC size. It was revealed that eyes with WC below the posterior subcapsule are more hyperopic than those with WC below the anterior subcapsule, and the former have a higher HOA and lower MTF than the latter.


Cataract/physiopathology , Computer Simulation , Refractive Errors/physiopathology , Visual Acuity/physiology , Aged , Cataract/diagnostic imaging , Corneal Wavefront Aberration/physiopathology , Female , Humans , Middle Aged , Refraction, Ocular/physiology
11.
J Clin Med ; 10(7)2021 Apr 04.
Article En | MEDLINE | ID: mdl-33916605

This study was aimed to evaluate the relationship between the area under the log contrast sensitivity function (AULCSF) and several optical factors in eyes suffering mild cataract. We enrolled 71 eyes of 71 patients (mean age, 71.4 ± 10.7 (standard deviation) years) with cataract formation who were under surgical consultation. We determined the area under the log contrast sensitivity function (AULCSF) using a contrast sensitivity unit (VCTS-6500, Vistech). We utilized single and multiple regression analyses to investigate the relevant factors in such eyes. The mean AULSCF was 1.06 ± 0.16 (0.62 to 1.38). Explanatory variables relevant to the AULCSF were, in order of influence, logMAR best spectacle-corrected visual acuity (BSCVA) (p < 0.001, partial regression coefficient B = -0.372), and log(s) (p = 0.023, B = -0.032) (adjusted R2 = 0.402). We found no significant association with other variables such as age, gender, uncorrected visual acuity, nuclear sclerosis grade, or ocular HOAs. Eyes with better BSCVA and lower log(s) are more susceptible to show higher AULCSF, even in mild cataract subjects. It is indicated that both visual acuity and intraocular forward scattering play a role in the CS function in such eyes.

12.
J Cataract Refract Surg ; 45(12): 1777-1781, 2019 12.
Article En | MEDLINE | ID: mdl-31856989

PURPOSE: To compare kinetic visual acuity, stereopsis, ocular deviation, and fusion amplitude before and after implantable collamer lens (ICL) surgery. SETTING: Sanno Hospital. DESIGN: Retrospective analysis. METHODS: The charts of adult patients who underwent implantation of an ICL with a central aquaport (V4c) for emmetropia were reviewed. The mean preoperative spherical equivalent and subjective astigmatism were -7.87 diopters (D) ± 3.13 (SD) and -0.75 ± 0.78 D, respectively. All measurements were obtained with full refraction before surgery and without spectacle correction after surgery. The kinetic visual acuity was measured with the AS-4D device. Stereopsis and ocular deviation were measured with the Titmus Stereotest and an alternate prism cover test, respectively. Fusion amplitude was determined from breakpoints measured using a prism. RESULTS: The study comprised 29 adult patients (58 eyes). One month postoperatively, the mean safety and efficacy indices were 1.13 ± 0.20 and 0.96 ± 0.25, respectively, and 57 eyes (98.7%) were within ±0.5 D of the target correction. The mean kinetic visual acuity (logarithm of the minimum angle of resolution) was 0.30 ± 0.21 preoperatively and 0.20 ± 0.15 (Snellen 20/40 versus 20/32) postoperatively and the mean stereopsis (seconds of arc), 48.5 ± 1.6 versus 41.5 ± 1.1; both improved significantly (P < .001 and P = .012, respectively). The mean distance ocular deviation (-4.0 ± 3.8 prism diopters [Δ] versus 2.8 ± 3.6 Δ; P = .002) and near ocular deviation (-6.5 ± 6.7 Δ versus 5.4 ± 6.9 Δ; P = .04) decreased significantly. The fusion amplitude increased for near vision only. CONCLUSIONS: ICL implantation improved kinetic visual acuity and stereopsis, decreased ocular deviation, and increased near fusion amplitude.


Depth Perception/physiology , Eye Movements/physiology , Lens Implantation, Intraocular/methods , Myopia, Degenerative/surgery , Phakic Intraocular Lenses , Refraction, Ocular/physiology , Visual Acuity , Adult , Female , Humans , Male , Middle Aged , Myopia, Degenerative/diagnosis , Myopia, Degenerative/physiopathology , Retrospective Studies , Young Adult
13.
Am J Ophthalmol Case Rep ; 12: 97-100, 2018 Dec.
Article En | MEDLINE | ID: mdl-30450443

PURPOSE: We report a case of cataract surgery in a patient with a detectable angle gamma due to macular heterotopia. OBSERVATION: A 48-year-old man had angle gamma due to macular heterotopia secondary to retinopathy of prematurity. The preoperative corrected distance visual acuity was 20/32 in the right eye and 20/200 in the left eye. Ocular deviation was esotropic at an angle of 70-80prism diopter. Only the right eye was capable of fixating due to the amblyopia in the left eye. The preoperative root mean square was measured (cornea: 1.32 µm, total: 1.64 µm in ordinary fixation position, cornea: 0.36 µm, total: 3.40 µm in pupil center position). The total aberration was lower in the ordinary fixation position than in the pupil center position. Corneal refractive power was 41.75 D in the ordinary fixation position and 43.05 D in the pupil center position. The axial lengths were 22.25 and 22.54 mm, respectively. We selected the VA60BBR intraocular lens (IOL) at +28.00 D based on the targeted fixation state. Target refraction was -1.32 D. The postoperative course was favorable, and the resulting visual acuity was 20/40. CONCLUSION: We report a case of cataract surgery on a patient with an angle gamma due to macular heterotopia. The postoperative course was favorable, and the patient's satisfaction was good considering that we selected the IOL's postoperative fixation state to meet the patient's occupational demands.

14.
Nippon Ganka Gakkai Zasshi ; 120(4): 296-302, 2016 Apr.
Article Ja | MEDLINE | ID: mdl-27209858

PURPOSE: To investigate the change in uncorrected visual acuity (UCVA) among schoolchildren in Bonin Islands. SUBJECTS AND METHODS: UCVA of schoolchildren aged 6 to 14 years, was collected from reports of School Health Examination Surveys conducted from 1981 to 2012. The proportion of schoolchildren with poor UCVA in the Bonin Islands was compared with those in metropolitan Tokyo. The results in Bonin Islands were also divided into two groups, before- and after-1996 when terrestrial television broadcasting service has been started, and the data of those two groups were compared. RESULTS: The proportion of schoolchildren with poor UCVA in Bonin Islands was lower than that in Tokyo. Among the residents of Bonin Islands, the proportion of schoolchildren with UCVA of < 1.0 was higher in the after-1996 group than in the before- 1996 group, with a clear increase in schoolchildren with poor UCVA after 1996 (p < 0.01, Fisher's exact test), examined among the 4th grade of elementary school or above. After 1996, 26.6% of first graders at a public junior high school had poor UCVA of < 0.7, whereas before 1996 no such case could be detected. CONCLUSION: The present study revealed that the proportions of schoolchildren with poor UCVA in Bonin Islands was lower than that in Tokyo; but in the residents of Bonin Islands after 1996, the proportion of the schoolchildren with poor UCVA increased.


Visual Acuity , Adolescent , Child , Female , Humans , Japan/epidemiology , Male , Myopia/epidemiology
16.
Graefes Arch Clin Exp Ophthalmol ; 254(4): 739-44, 2016 Apr.
Article En | MEDLINE | ID: mdl-26895160

BACKGROUND: A modified implantable collamer lens (ICL) with a central hole with a diameter of 0.36 mm, referred to as a hole-ICL, was created to improve aqueous humour circulation. The aim of this study is to investigate the ideal hole size in a hole-ICL from the standpoint of the fluid dynamic characteristics of the aqueous humour using computational fluid dynamics. METHODS: Fluid dynamics simulation using an ICL was performed with thermal-hydraulic analysis software FloEFD V 12.2 (Mentor Graphics Corp.). In the simulation, three-dimensional eye models based on a modified Liou-Brennan model eye with a conventional ICL (Model ICM, Staar Surgical) and a hole-ICL were used. The hole-ICL was -9.0 dioptres (D) and 12.0 mm in length, with an optic zone of 5.5 mm. The vaulting was 0.50 mm. The quantity of aqueous humour produced by the ciliary body was set at 2.80 µL/min. Flow distribution between the anterior surface of the crystalline lens and the posterior surface of the ICL was calculated, and trajectory analysis was performed. RESULTS: With an increase in the central hole size, the velocity of the aqueous humour increased, with the peak velocity occurring at a diameter of approximately 0.4 mm. Once the diameter had increased above 0.4 mm, the velocity then decreased. The velocity difference between the cases of a central hole size of 0.1 mm and 0.2 mm was significant. CONCLUSION: The desirable central hole size was 0.2 mm or larger in terms of flow dynamics. The current model, based on a central hole size of 0.36 mm, was close to ideal. The optimisation of the hole size should be performed based on results from a long-term clinical study so as to analyse the incidence rate of secondary cataract and optical performance.


Aqueous Humor/physiology , Computer Simulation , Hydrodynamics , Phakic Intraocular Lenses , Ciliary Body/metabolism , Humans , Prosthesis Design
17.
Sci Rep ; 5: 12606, 2015 Jul 28.
Article En | MEDLINE | ID: mdl-26218972

To compare subjective refraction under binocular and monocular conditions, and to investigate the clinical factors affecting the difference in spherical refraction between the two conditions. We examined thirty eyes of 30 healthy subjects. Binocular and monocular refraction without cycloplegia was measured through circular polarizing lenses in both eyes, using the Landolt-C chart of the 3D visual function trainer-ORTe. Stepwise multiple regression analysis was used to assess the relations among several pairs of variables and the difference in spherical refraction in binocular and monocular conditions. Subjective spherical refraction in the monocular condition was significantly more myopic than that in the binocular condition (p < 0.001), whereas no significant differences were seen in subjective cylindrical refraction (p = 0.99). The explanatory variable relevant to the difference in spherical refraction between binocular and monocular conditions was the binocular spherical refraction (p = 0.032, partial regression coefficient B = 0.029) (adjusted R(2) = 0.230). No significant correlation was seen with other clinical factors. Subjective spherical refraction in the monocular condition was significantly more myopic than that in the binocular condition. Eyes with higher degrees of myopia are more predisposed to show the large difference in spherical refraction between these two conditions.


Myopia/physiopathology , Refraction, Ocular/physiology , Vision, Binocular/physiology , Adult , Female , Humans , Male , Visual Acuity/physiology
18.
Sci Rep ; 5: 10456, 2015 May 21.
Article En | MEDLINE | ID: mdl-25994984

This study aimed to investigate the effect of myopic defocus on visual acuity after phakic intraocular lens (IOL) implantation and wavefront-guided laser in situ keratomileusis (wfg-LASIK). Our prospective study comprised thirty eyes undergoing posterior chamber phakic IOL implantation and 30 eyes undergoing wfg-LASIK. We randomly measured visual acuity under myopic defocus after cycloplegic and non-cycloplegic correction. We also calculated the modulation transfer function by optical simulation and estimated visual acuity from Campbell &Green's retinal threshold curve. Visual acuity in the phakic IOL group was significantly better than that in the wfg-LASIK group at myopic defocus levels of 0, -1, and -2 D (p < 0.001, p < 0.001, and p = 0.02, Mann-Whitney U-test), but not at a defocus of -3 D (p = 0.30). Similar results were also obtained in a cycloplegic condition. Decimal visual acuity values at a myopic defocus of 0, -1, -2, and -3 D by optical simulation were estimated to be 1.95, 1.21, 0.97, and 0.75 in the phakic IOL group, and 1.39, 1.11, 0.94, and 0.71 in the wfg-LASIK group, respectively. From clinical and optical viewpoints, phakic IOL implantation was superior to wfg-LASIK in terms of the postoperative visual performance, even in the presence of low to moderate myopic regression.


Keratomileusis, Laser In Situ , Lens Implantation, Intraocular , Myopia/therapy , Visual Acuity/physiology , Adult , Female , Humans , Male , Myopia/pathology , Phakic Intraocular Lenses , Prospective Studies , Young Adult
19.
J Cataract Refract Surg ; 41(1): 193-8, 2015 Jan.
Article En | MEDLINE | ID: mdl-25466486

PURPOSE: To determine whether subsurface nanoglistening in hydrophobic acrylic intraocular lenses (IOL) diminishes visual performance. SETTING: Department of Ophthalmology, Kanazawa Medical University, Uchinada, Ishikawa, Japan. DESIGN: Experimental study. METHODS: The effect of subsurface nanoglistenings was simulated using optical design software Lighttools and Code V with the Liou-Brenann model eye and an acrylic IOL. Peak irradiance of the retina, forward light scattering, and modulation transfer function (MTF) were evaluated. During optical simulation, particle diameters were set at 100 nm, 150 nm, and 200 nm and volume ratios at 0%, 0.05%, 0.1%, 0.2%, 0.5%, and 1.0%. RESULTS: Peak irradiance decreased as subsurface nanoglistening volume ratio and particle size increased. At a volume ratio of 0.05%, the peak irradiance of subsurface nanoglistening particles 100 nm, 150 nm, and 200 nm in diameter decreased 0.7%, 1.8%, and 2.9%, respectively, compared with those at volume ratio 0% (no subsurface nanoglistenings). At a volume ratio of 0.1%, the peak irradiance of subsurface nanoglistening particles 100 nm, 150 nm, and 200 nm decreased 1.5%, 3.6%, and 5.7%, respectively. Forward light scattering increased with increased size of subsurface nanoglistening particle and volume ratio. The MTF was not altered by changes in subsurface nanoglistening particle size or volume ratio. CONCLUSIONS: Subsurface nanoglistenings increased forward scattering slightly and reduced irradiance but significantly diminished retinal image. The effect of subsurface nanoglistenings on visual function in the absence of severe retinal disease was minimal. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.


Glare , Lenses, Intraocular , Models, Theoretical , Retina/radiation effects , Scattering, Radiation , Vacuoles , Vision, Ocular/physiology , Humans , Light
20.
J Refract Surg ; 29(10): 716-20, 2013 Oct.
Article En | MEDLINE | ID: mdl-23952844

PURPOSE: To investigate the association between ocular dominance (sighting dominance) and refractive asymmetry in phakic patients. METHODS: This retrospective study included 3,012 patients with a mean age of 29.0 ± 5.3 years (range: 20 to 39 years). Refractive error was determined with cycloplegic refraction and axial length was determined with IOLMaster (Carl Zeiss Meditec, Dublin, CA). Ocular dominance was assessed using the hole-in-the-card test. RESULTS: The right and left eyes were dominant in 77.7% and 22.3% of the patients, respectively. In the high anisometropia group (⩾ 2.0 diopters), the non-dominant eyes had significantly higher myopic spherical equivalents and longer axial lengths than the dominant eyes (P < .05). However, there were no significant differences in these parameters in the low anisometropia group. CONCLUSION: The current study revealed that non-dominant eyes had a greater myopic refractive error and longer axial length than the dominant eyes, especially in the patients who had high amounts of anisometropia.


Anisometropia/physiopathology , Dominance, Ocular/physiology , Adult , Anisometropia/diagnosis , Axial Length, Eye , Female , Humans , Male , Mydriatics/administration & dosage , Pupil/drug effects , Refraction, Ocular/physiology , Retrospective Studies , Visual Acuity/physiology , Young Adult
...