Extended just-noticeable difference for ultralow-luminance displays used in diagnostic imaging.

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.

Modulation transfer function of implantable phakic intraocular contact lens (IPCL) for myopia and presbyopia.

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.

Cone contrast test-HD: sensitivity and specificity in red-green dichromacy and the impact of age.

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.

Relationship of Low-luminance Visual Acuity with Ocular Aberrations in Older Participants.

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.

Effect of hole size on fluid dynamics of a posterior-chamber phakic intraocular lens with a central perforation by using computational fluid dynamics.

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.

[Epidemiological Study of Poor Visual Acuity among Schoolchildren in Bonin Islands].

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.

Anterior Segment Optical Coherence Tomography Findings in Capsular Block Syndrome with Improvement in Myopia following Neodymium-Yttrium Aluminum Garnet Laser Treatment.

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.

Machine learning judged neutral facial expressions as key factors for a "good therapist" within the first five minutes: An experiment to simulate online video counselling.

Objective: Machine learning models were employed to discern patients' impressions from the therapists' facial expressions during a virtual online video counselling session. Methods: Eight therapists simulated an online video counselling session for the same patient. The facial emotions of the therapists were extracted from the session videos; we then utilized a random forest model to determine the therapist's impression as perceived by the patients. Results: The therapists' neutral facial expressions were important controlling factors for patients' impressions. A predictive model with three neutral facial features achieved an accuracy of 83% in identifying patients' impressions. Conclusions: Neutral facial expressions may contribute to patient impressions in an online video counselling environment with spatiotemporal disconnection. Innovation: Expression recognition techniques were applied innovatively to an online counselling setting where therapists' expressions are limited. Our findings have the potential to enhance psychiatric clinical practice using Information and Communication Technology.

Association between ocular dominance and refractive asymmetry.

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.

Effect of incomplete blinking on tear film stability.

PURPOSE: The purpose of this study is to assess changes in tear film stability caused by incomplete blinking. METHODS: Eleven subjects (mean age, 21.3 years) participated in this study. All subjects had a visual acuity of 20/20 or better and normal ocular health. The subjects were asked to play a game for 60 min on a personal computer as part of a visual display terminal (VDT) experiment. Each subject's blinking was observed by a Web camera that was attached to the top of the display. Every 15 min, the VDT experiment was interrupted for measurement. An RT-7000 (Tomey Co., Ltd., Nagoya, Japan) was used to measure ring breakup time as a parameter of tear film stability. An OPD-Scan II ARK-10000 (NIDEK Co., Ltd., Aichi, Japan) was used to measure corneal aberrations. RESULTS: Although the total blink rate changed very little, the complete and incomplete blink rates fluctuated during the VDT experiment. Both types were plotted along symmetrical cubic approximation curves. Noninvasive (ring) breakup time at 30 min (4.33 ± 2.57 s) was significantly shorter (p < 0.01) than that at baseline before the VDT experiment (8.62 ± 1.54 s). After 30 min, the incomplete blink rate began decreasing (fewer incomplete blinks), whereas the complete blink rate began increasing. Ring breakup time increased (improved) after 45 min; however, the incomplete blink rate began to increase again after approximately 50 min. CONCLUSIONS: Even if the total blink rate decreases, the tear film remains stable so long as almost all blinks are complete. The incomplete blinking contributes to tear film instability and is variable with prolonged VDT exposure. Our study indicated that the tear film stability was determined by blinking quality, and the predominance of blinking type relates to tear film stability.

Prevalence of Accommodative Microfluctuations in Eyes after Cataract Surgery.

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.

Fluid dynamics simulation of aqueous humour in a posterior-chamber phakic intraocular lens with a central perforation.

BACKGROUND: A modified implantable collamer lens (ICL) with a central hole (diameter, 0.36 mm), a "Hole-ICL", was created to improve aqueous humour circulation. The aim of this study was to investigate the fluid dynamic characteristics of aqueous humour in a Hole-ICL using computational fluid dynamics. METHODS: Fluid dynamics simulation using an ICL was performed with thermal-hydraulic analysis software FloEFD V5 (Mentor Graphics Corp.). For the simulation, three-dimensional eye models based on a modified Liou-Brennan model eye with conventional ICL (Model ICM, STAAR SURGICAL) and a Hole-ICL were used. Both ICLs were -9.0 diopters (D) and 12.0 mm in length, with an optic 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 also calculated, and trajectory analysis was performed. RESULTS: The flow velocity 0.25 mm in front of the centre of the crystalline lens was 1.52 × 10(-1) mm/sec for the Hole-ICL and 1.21 × 10(-5) mm/sec for the conventional ICL. Outward flow from the hole in the Hole-ICL was confirmed by trajectory analysis. CONCLUSION: These results suggest that Hole-ICLs improve the circulation of aqueous humour to the anterior surface of the crystalline lens.

Effect of astigmatism on apparent accommodation in pseudophakic eyes.

PURPOSE: To investigate the factors affecting apparent accommodation in pseudophakic eyes from a clinical viewpoint and the effects of corneal and refractive astigmatism on this accommodation from an optical viewpoint. METHODS: We retrospectively examined 62 eyes of 33 patients who had undergone phacoemulsification with monofocal intraocular lens implantation. We quantitatively assessed the amplitude of apparent accommodation using an accommodometer 3 months after surgery. Multiple regression analysis was used to assess the factors affecting apparent accommodation. We also estimated the accommodation in eyes with corneal astigmatism by optical simulation. RESULTS: The mean amplitude of apparent accommodation was 1.58 = 0.65 D. Explanatory variables relevant to this accommodation were in order of influence, pupil diameter (partial regression coefficient B = 0.293, p = 0.008), and corneal multifocality (B = 0.101, p = 0.03). Other explanatory variables such as age, gender, axial length, corneal astigmatism, and refractive astigmatism showed no significant relationship with this accommodation. The estimated apparent accommodations for a 3.0 mm pupil by optical simulation were 1.25, 1.25, 1.25, 0.75, and 0 D, in eyes with corneal astigmatism of 0, 0.5, 1.0, 1.5, and 2.0 D, respectively. Similar results were obtained for a 4.0 mm pupil. CONCLUSIONS: Eyes with smaller pupil diameter and eyes with greater corneal multifocality are more predisposed to have greater apparent accommodation. However, from clinical and optical viewpoints, corneal or refractive astigmatism does not significantly contribute to apparent accommodation after cataract surgery, suggesting that it may be of less significance that the astigmatism is consciously retained in consideration of this accommodation in astigmatic eyes.

[Comparison of central visual field visualization while using a combination of spherical intraocular lenses with vitreous contact lenses].

OBJECTIVE: To investigate intraocular lens (IOL) and vitreous contact lens (VCL) combinations that provide good central visual field visualization in vitreous surgery. METHOD: ZEMAX optical design software was used to perform optical simulations using the ray tracing method on a Gullstrand eye model. The implanted IOL was assumed to consist of material with a refractive index of 1.550 (high refractive index acrylic IOL), 1.470 (low refractive index acrylic IOL) and 1.413 (silicon IOL), and was set as a biconvex spherical lens (optical diameter 6 mm, 23.5 D). The VCL was assumed to have a refractive index of 1.900 (HEMA VCL), 1.490 (PMMA VCL) and 1.413 (silicon VCL), and was set as a concave lens (optical diameter 10 mm) with a flat anterior surface and a posterior surface with a radius of curvature of 7.70 mm. The spherical aberration of the overall optical system, including the IOL-implanted eyeball and the VCL, was calculated. RESULTS: Spherical aberration was lowest with the silicon VCL for the high refractive index acrylic IOL and with the PMMA VCL for the low refractive index acrylic and silicon IOLs. CONCLUSION: The combinations providing the best central visual field visualization in vitreous surgery are a silicon VCL for implantation of a high refractive index acrylic IOL and a PMMA VCL for implantation of a low refractive index acrylic or silicon IOL.

Refractive and visual function changes in twilight conditions.

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.

Analyzing Effect of Waterclefts on Visual Functions Via Optical Simulations.

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.

High visibility colored fabrics for normal trichromats and individuals with color vision defects in a sunset-simulated environment.

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.

Evaluation of ocular biometry in the Japanese population using a multicenter approach: Prospective observational study.

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.

Modulation transfer function of intraocular collamer lens with a central artificial hole.

BACKGROUND: A modified implantable collamer lens (ICL) with a central hole (diameter 0.36 mm), "Hole-ICL", was created to improve aqueous humour circulation. The aim of this study is to investigate the effects of ICL power and the relationship between pupil size and modulation-transfer functions (MTFs) in a Hole-ICL in vitro. METHODS: The ICL and intraocular lens (IOL) studied were the Collamer ICL (Model ICM, STAAR Surginal) and the monofocal IOL AF-1 (VA-60BBR, HOYA). The ICLs' powers were -20.0 diopters (D), -10.0 D, -5.0 D, +3.0 D, and +10.0 D. A modified ICL with a central hole (diameter 0.36 mm), "Hole-ICL", was created. The monofocal IOL, which was used as an artificial crystalline lens, was +30.0 D in power, and it was 13.0 mm in length with an optic diameter of 6.0 mm. The line-spread function (LSF) was recorded with the OPAL Vector System (Image Science Ltd.), and a model eye (Menicon Co.) was used that consisted of a wet cell. A conventional ICL or Hole-ICL was placed in the posterior chamber of the model eye. The MTF was calculated from the LSF using fast Fourier transform techniques. Furthermore, we investigated the relationship between pupil size and the MTF of the ICL for -5.0 D. The sizes of the effective aperture were 2.0, 3.0, 4.0, and 5.0 mm. RESULTS: The in-focus contrasts of the conventional ICL at 100 cyc/mm for a 3.0-mm effective aperture were 37%, 40%, 39%, 38%, and 39% for -20.0 D, -10.0 D, -5.0 D, +3.0 D, and +10.0 D respectively. The in-focus contrasts of the Hole-ICL at 100 cyc/mm for a 3.0-mm effective aperture were 37%, 40%, 39%, 38%, and 38% for -20.0 D, -10.0 D, -5.0 D, +3.0 D, and +10.0 D respectively. The results for a 2.0-mm effective diameter showed that the in-focus MTF in the Hole-ICL was lower than in the conventional ICL, although the difference was small. CONCLUSION: These results suggest that differences in MTF between the Hole-ICL and the conventional ICL for various ICL powers and effective pupil diameters were small and clinically negligible.