Search Results (11)

Our purpose is to evaluate the binocular contrast sensitivity function (CSF) in a presbyopic population and compare the results obtained with four different simultaneous-vision center-near multifocal contact lens (MCL) designs for distance vision under two illumination conditions. Additionally, chromatic CSF (red-green and blue-yellow) was evaluated. A randomized crossover pilot study was conducted. Four daily disposable lens designs, based on simultaneous-vision and center-near correction, were compared. The achromatic contrast sensitivity function (CSF) was measured binocularly using the CSV1000e test under two lighting conditions: room light on and off. Chromatic CSF was measured using the OptoPad-CSF test. Comparison of achromatic results with room lighting showed a statistically significant difference only for 3 cpd (p = 0.03) between the baseline visit (with spectacles) and all MCLs. Comparison of achromatic results without room lighting showed no statistically significant differences between the baseline and all MCLs for any spatial frequency (p > 0.05 in all cases). Comparison of CSF-T results showed a statistically significant difference only for 4 cpd (p = 0.002). Comparison of CSF-D results showed no statistically significant difference for all frequencies (p > 0.05 in all cases). The MCL designs analyzed provided satisfactory achromatic contrast sensitivity results for distance vision, similar to those obtained with spectacles, with no remarkable differences between designs. Chromatic contrast sensitivity for the red-green and blue-yellow mechanisms revealed some differences from the baseline that should be further investigated in future studies. Full article

Background: The World Health Organization defines myopia as a global epidemic. Its growing prevalence and the increasingly early age onset all raise a major concern for public health due to the elevated risk of loss and deterioration of visual function as a result of myopia-related ocular pathological complications. However, it remains unclear whether the vision-related quality of life of patients with myopia is the same as in healthy individuals. The aim of the present study is to assess the quality of life in children and adolescents with myopia between the ages of 8 and 16 years, who underwent observation at USBOBAL-Varna. Methods: This study prospectively included 190 patients with myopia between −1.00 and −5.50 D, corrected with different optical aids. After a thorough physical ocular examination and inquiry into the best visual acuity with and without distance correction, specially designed questionnaires were completed by the patients and their parents/guardians for the purpose of the study. The data from the questionnaires was statistically processed. The mean age of the patients in the study was 11.65 years, 101 were female and 89 were male. Of these, 83 wore monofocal glasses, 50 were monofocal and 47 were multifocal contact lenses, and 10 wore ortho-K lenses. Results: No significant difference in best corrected visual acuity (BCVA) was found among the three types of optical correction (p-value > 0.05). Cronbach’s alpha of the questionnaire for all 10 factors was higher than 0.6, indicating acceptable internal consistency. Significantly higher scores were reported for overall, near, and distance vision, symptoms, appearance, attitude, activities and hobbies, handling, and perception for soft contact lens wearers than for spectacle wearers (p-value < 0.05). Ortho-K wearers performed better than spectacle wearers in all aspects except for pronounced symptoms (p = 0.74). No significant difference was found between ortho-K wearers and soft contact lens wearers for any factor (p > 0.05). Conclusions: Patients wearing spectacles and with myopia above −5.00 D had the highest anxiety scores and lower quality of life among all myopic participants. The research on the quality of life in children with myopia with different refractive errors and optical correction devices is crucial for improving corrective devices and meeting the needs of patients. Full article

Background: The objective was to preliminarily evaluate the short-term clinical outcomes obtained in presbyopic patients with a novel, multifocal, customized corneo-scleral contact lens (CSCL). Methods: A total of 11 presbyopic subjects (age 45–80 years, corrected-distance visual acuity ≤ 0.1 LogMAR, near addition ≥ +1.00 D) were recruited and fitted with a multifocal corneo-scleral contact lens in this pilot study. Pre-fitting evaluations included stereopsis, contrast sensitivity (CS), and ocular aberrometry, with follow-up assessments conducted at 20 min and 1-month post-fitting. The defocus curve was also measured to assess visual performance across varying distances. Results: Twenty-two eyes from 11 participants (53.9 ± 4.7 years, 10 female) were included in this study. Significant changes were observed post-fitting for primary and secondary spherical aberration, coma, and stereopsis (p ≤ 0.033). No significant changes in Strehl ratio and total root mean square were detected (p ≥ 0.182). Binocular contrast sensitivity was better with spectacles than with the fitted CSCL at all frequencies (p ≤ 0.048), but the change in monocular did not reach statistical significance for 18 cycles per degree (p = 0.109). All patients and 90.9% of patients achieved a visual acuity of 0.0 LogMAR or better at distance and at intermediate, respectively, and 91.8% achieved 0.3 LogMAR or better for near vision. Conclusions: The customized CSCL evaluated provided functional recovery of visual quality across distances, with acceptable reductions of CS and stereopsis that are comparable to those reported for other multifocal contact lenses. Full article

Background/Objectives: Preceding studies have reported the efficacy of multifocal contact lenses (MFCLs) in slowing myopia progression. Recently, a novel type of MFCL, i.e., extended depth-of-focus (EDOF) contact lens (CL), was designed. Here, we retrospectively investigated myopia progression associated with EDOF CL wear. Methods: Twenty-four consecutive myopic children (24 eyes; mean age, 13.9 years) received EDOF CLs to control myopia progression and participated in the study. We measured the axial length (AL), spherical equivalent (SE), and choroidal thickness (CT) at baseline and after 1 year of lens wear and compared the changes. Results: The mean baseline AL, SE, and CT were, respectively, 26.31 mm, −6.38 diopter (D), and 235 μm, and at 1 year 26.40 mm (p = 0.03), −6.61 D (p = 0.05), and 244 μm (p = 0.18). The AL decreased in 20.8% of cases (≧−0.05 mm/year), whereas 20.8% and 58.4% of cases had stabilization of the AL or an increased AL (≧+0.05 mm/year), respectively. The patients with a decreased AL engaged in a mean outdoor activity time of 200.6 min/day, the patients with an increased AL (≧+0.05 mm/year) engaged in a mean outdoor activity time of 126.7 min/day. The change in the AL was correlated significantly with the change in the CT (β = −0.46, p < 0.05), and 80% of patients with a shortened AL had increased CT (≧+20 μm/year). Conclusions: Our data showed that the AL stabilized or decreased in over 40% of myopic patients wearing EDOF CLs. Full article

Background: This study aimed to analyze the research progress on the use of a multifocal lens for myopic control throughout the 21st century, utilizing bibliometric analysis. Methods: Publications related to multifocal lenses from 2001 to 2024 were searched on the Web of Science core collection (WoSCC) database. VOSviewer (Version 1.6.19) and Bibliometrix package (Version 4.3.0) were used to perform the bibliometric analysis. Primary information including the publication number per year, country or region, journal, keyword, and title of the literature was extracted and analyzed. Results: A total of 234 articles from 31 countries were retrieved. The number of publications related to multifocal lenses had a rapid growth phase from 2016 to 2024. The United States, Australia, China, and Spain emerged as leading contributors to the research landscape. Ophthalmic and Physiological Optics was the most popular journal in this field, and the most frequently cited article was published in Optometry and Vision Science. Myopic progression was the main topic in this research field as well as the principal keywords of emerging research hotspots. Conclusions: Our bibliometric study provides a pioneering overview of the research trends and evolution in the application of a multifocal lens for myopic control. These findings provide a deep insight into current research frontiers and hot directions, offering a valuable reference for further research. Full article

Background: Myopia management contact lenses have been shown to successfully decrease the rate of eye elongation in children by changing the peripheral refractive profile of the retina. Despite the efforts of the scientific community, the retinal response mechanism to defocus is still unknown. The purpose of this study was to evaluate the local electrophysiological response of the retina with a myopia control contact lens (CL) compared to a single-vision CL of the same material. Methods: The retinal electrical activity and peripheral refraction of 16 eyes (16 subjects, 27.5 ± 5.7 years, 13 females and 3 males) with myopia between −0.75 D and −6.00 D (astigmatism < 1.00 D) were assessed with two CLs (Filcon 5B): a single-vision (SV) CL and an extended-depth-of-focus (EDOF) CL used for myopia management. The peripheral refraction was assessed with an open-field WAM-5500 auto-refractometer/keratometer in four meridians separated by 45° at 2.50 m distance. The global-flash multifocal electroretinogram (gf-mfERG) was recorded with the Reti-port/scan21 (Roland Consult) using a stimulus of 61 hexagons. The implicit time (in milliseconds) and response density (RD, in nV/deg²) of the direct (DC) and induced (IC) components were used for comparison between lenses in physiological pupil conditions. Results: Although the EDOF decreased both the HCVA and the LCVA (one and two lines, respectively; p < 0.003), it still allowed a good VA. The EDOF lens induced a myopic shift in most retinal areas, with a higher and statistically significant effect on the nasal retina. No differences in the implicit times of the DC and IC components were observed between SV and EDOF. Compared with the SV, the EDOF lens showed a higher RD in the IC component in the foveal region (p = 0.032). In the remaining retinal areas, the EDOF evoked lower, non-statistically significant RD in both the DC and IC components. Conclusions: The EDOF myopia control CL enhanced the response of the inner layers of the fovea. This might suggest that, besides other mechanisms potentially involved, the central foveal retinal activity might be involved in the mechanism of myopia control with these lenses. Full article

This pilot study was conducted to evaluate the effect on refraction and optical quality of the increase in the corneal clearance after fitting a specific model of scleral contact lens (ScCL) in healthy subjects. A total of 15 eyes from 15 subjects were enrolled in the study, with evaluation of refraction, ocular aberrations and central corneal clearance with the same model of ScCL (ICD Toric, Paragon Vision Science, Gilbert, AZ, USA), but using 3 different sagittal heights: 4200, 4500 and 4800 µm. Mean values of corneal clearance for each ScCL fitted were 418.1 ± 112.1, 706.5 ± 120.3 and 989.9 ± 117.0 µm, respectively. Significant changes were detected in the spherical equivalent and high-order aberrations, especially coma and spherical aberration, when fitting ScCLs of increasing sagittal heights compared to the pre-fitting values. In conclusion, the increase in central corneal clearance when fitting ScCLs affects refraction, leading to a more myopic refractive error, and inducing an increase in different ocular HOAs. This should be considered when fitting ScCLs, especially multifocal designs. Full article

Exposing the retina to a simultaneous myopic defocus is an optical method that has shown a promising effect in slowing the progression of myopia. Optical treatments applying a simultaneous defocus are available in the form of soft contact lenses or multifocal lenses originally designed to correct presbyopia. Orthokeratology is another optical method that slows down the progression of myopia. With orthokeratology, it is hypothesized that a change in peripheral refraction could slow the progression of myopia. We aimed to measure the accommodation response between monofocal and multifocal contact lenses in young subjects. Additionally, we performed a ray-tracing simulation to visualize the quality of the retinal image and the refractive status in the retinal periphery. The accommodation and pupil size measurements were performed on 29 participants aged 24.03 ± 2.73 years with a refractive error (spherical equivalent) of −1.78 ± 1.06 D. With the multifocal lens in situ, our participants showed less accommodation in comparison to the monofocal contact lens (mean difference, 0.576 ± 0.36 D, p > 0.001) when focusing on a near target at 40 cm. Pupil size became smaller in both contact lens groups during an accommodation of 0.29 ± 0.69 mm, p ≤ 0.001 and 0.39 ± 0.46 mm, p ≤ 0.001 for monofocal and multifocal contact lenses, respectively. The ray-tracing model showed a degradation for central and peripheral vision with the multifocal contact lens. The peripheral refraction was relatively myopic in both contact lens conditions up to 30°. Even if the accommodation ability is without fault, parts of simultaneous myopic defocus are used for the near task. The peripheral refraction in the ray-tracing model was not different between the two contact lenses. This is contrary to the proposed hypothesis that myopic peripheral refraction slows down the progression of myopia in current optical methods. Full article

CONTEXT: Authors have refined myopia control strategies (MCS) from their experience treating more than 800 children who were followed at the Montreal School of Optometry Clinic (CUV). They developed a treatment algorithm known as the Montreal Experience (ME). Contrary to many other MCS, treatment modalities are selected after careful evaluation of a patient’s parameters (rate of progression, age of myopia onset, corneal parameters, pupil area), the risk factors for ocular pathology (growth charts), and taking into account the patient’s lifestyle and potential compliance. This represents a customized approach for each patient. PURPOSE: To evaluate the efficacy of MCS used following ME algorithm; the primary outcome relates to axial length progression over 24 months. METHODS: This is a retrospective study, conducted after approval of University IRB. Data were extracted from the file of each patient who: (1) consulted CUV between January 2017 and December 2018 and (2) were kept under the same MCS (same design/concentration). Clinical population is composed of 298 patients (35% Caucasian; 45% Asian; 20% others), with a median age of 11 (range 5–18). The treatment options were orthokeratology (OK-4 designs; N = 140), multifocal soft contact lenses (SMCL; 5 designs; N = 128), and low-dose atropine (LDA 0.01% to 0.25%; N = 42). RESULTS: Results are analyzed through sophisticated statistical models, designed for this purpose. At the end of a stepwise selection process that sequentially removed model terms that were not statistically significant, nine model terms remained: month, modality, the interaction of month and modality, refraction (SEQ), the interaction of SEQ and modality, gender, age, the interaction of age and month, and the interaction of age and modality. A total of 298 files were kept for analysis. Participant age varied from 9.7 to 12.5 years old. Baseline AL varied from 24.9 to 25.3 mm and SE refraction was −3.7 + 1.7 D on average. This study population was divided between Caucasian (34%), Asian (44%), and other ethnic origins (22%). Overall results indicate that results vary according to modality and months only. There is no statistical difference based on age, gender, and SEQ. All methods used were effective to slow the natural AL growth. Evolution was the lowest when using smaller treatment zones OK lenses (0.249 mm) and the highest (0.376 mm) for those treated with LDA. This OK advantage was statistically significant versus other modalities at 1 and 2 years. CONCLUSION: The Montreal Experience reveals that personalized MCS may be effective to manage myopia efficiently. It shows AL evolution comparable to the documented natural evolution of emmetropes, especially when using customized or smaller treatment zone OK lens design. Future work on other populations will confirm this tendency. Full article

We conducted a prospective, paired-eye, investigator masked study in 30 children with myopia (−1.25 D to −4.00 D; age 10 to 14 years) to test the efficacy of a novel multifocal orthokeratology (MOK) lens compared to conventional orthokeratology (OK) in slowing axial eye growth. The MOK lens molded a center-distance, multifocal surface onto the anterior cornea, with a concentric treatment zone power of +2.50 D. Children wore an MOK lens in one eye and a conventional OK lens in the fellow eye nightly for 18 months. Eye growth was monitored with non-contact ocular biometry. Over 18 months, MOK-treated eyes showed significantly less axial expansion than OK-treated eyes (axial length change: MOK 0.173 mm less than OK; p < 0.01), and inner axial length (posterior cornea to anterior sclera change: MOK 0.156 mm less than OK, p < 0.01). The reduced elongation was constant across different baseline progression rates (range −0.50 D/year to −2.00 D/year). Visual acuity was less in MOK vs. OK-treated eyes (e.g., at six months, MOK: 0.09 ± 0.01 vs. OK: 0.02 ± 0.01 logMAR; p = 0.01). We conclude that MOK lenses significantly reduce eye growth compared to conventional OK lenses over 18 months. Full article

Presbyopia is an age-related disorder where the lens of the eye hardens so that focusing on near objects becomes increasingly difficult. This complaint affects everyone over the age of 50. It is becoming progressively more relevant, as the average age of the global population continues to rise. Bifocal or varifocal spectacles are currently the best solution for those that require near and far vision correction. However, many people prefer not to wear spectacles and while multifocal contact lenses are available, they are not widely prescribed and can require significant adaptation by wearers. One possible solution is to use liquid crystal contact lenses that can change focal power by applying a small electric field across the device. However, the design of these contact lenses must be carefully considered as they must be comfortable for the user to wear and able to provide the required change in focal power (usually about +2D). Progress towards different lens designs, which includes lens geometry, liquid crystal choices and suitable alignment modes, are reviewed. Furthermore, we also discuss suitable electrode materials, possible power sources and suggest some methods for switching the lenses between near and far vision correction. Full article