-
Journal of Cataract and Refractive... May 2024To determine the effectiveness of the correction of corneal astigmatism utilizing the Alcon Image Guidance system (Ft. Worth, Texas) versus manual marking in the...
PURPOSE
To determine the effectiveness of the correction of corneal astigmatism utilizing the Alcon Image Guidance system (Ft. Worth, Texas) versus manual marking in the orientation of femtosecond laser-assisted astigmatic keratotomy incisions.
SETTING
This study was based in a private practice in Albany, New York, USA.
DESIGN
Retrospective review of patients undergoing FLACS from January 2018 to June 2022.
METHODS
Patients who underwent FLACS with Image Guidance (IG) and without IG were investigated. Variables including pre-operative K values, cylinder, spherical equivalent (SE), and visual acuity (VA) were collected, as well as the cyclorotation angle delta registered by IG, post- operative refractive cylinder, SE, and VA. The primary outcome was post-operative refractive cylinder in patients with IG compared to those without IG.
RESULTS
A total of 160 eyes were included, with 103 eyes who had IG and 57 eyes who did not have IG. Post-operative cylinder was similar in those with IG (0.31 +/- 0.36 D) compared to those without IG (0.31 +/- 0.37 D) (p=0.97). Average cyclorotation in the IG group was 2.82 ± 3.03 degrees. When cyclorotation was stratified into three groups (<2.8 degrees, 2.8-8.5 degrees, >8.5 degrees), no differences were found in post-operative refractive cylinder (p=0.35).
CONCLUSIONS
Patients who underwent FLACS with Image Guidance had similar post-operative cylinder outcomes compared to those without Image Guidance. This study suggests that the accommodation of cyclotorsion using an advanced image guidance system is similar to that obtained with manual marking techniques in patients having 2 diopters or less of astigmatism corrected.
PubMed: 38739530
DOI: 10.1097/j.jcrs.0000000000001477 -
Clinical Ophthalmology (Auckland, N.Z.) 2024To evaluate the impact on the lag of accommodation (LOA) in emmetropic children after short-term wear of full-field Diffusion Optics Technology (DOT) spectacle lenses,... (Clinical Trial)
Clinical Trial
PURPOSE
To evaluate the impact on the lag of accommodation (LOA) in emmetropic children after short-term wear of full-field Diffusion Optics Technology (DOT) spectacle lenses, designed to modulate retinal contrast to control myopia progression.
PATIENTS AND METHODS
This was a single-visit, prospective, randomized, subject-masked study of emmetropes (ametropes ±1.00D or less in each meridian) with no history of myopia control treatment. Unaided logMAR visual acuity was measured, and ocular dominance was determined using the sighting method. In a randomized order, participants wore plano full-field contrast management (DOT) spectacles (no clear central aperture) or control spectacles (standard single vision spectacle lenses). Each participant was given 5 minutes for adaptation to the respective lenses before open field autorefraction measurements were taken at 6 meters and 40 cm. Ten measurements were taken for each eye. Data were evaluated from the right eye and the dominant eye separately.
RESULTS
A total of 30 participants (20 females and 10 males) with a mean age of 10.4 ± 2.8 (7 to 17) years completed the study. There was no significant difference in right eye mean LOA with contrast management spectacles 0.57 ± 0.39D versus control spectacles 0.62 ± 0.34D; Wilcoxon test, p = 0.37. For dominant eyes, LOA values were 0.60 ± 0.40D and 0.68 ± 0.33D with contrast management spectacles and control spectacles, respectively (p = 0.14). Additionally, no significant difference was observed in mean LOA between males and females or between age groups (7-11 years vs 12-17 years) for either right or dominant eyes with contrast management or control spectacles (all p > 0.05).
CONCLUSION
Full-field contrast management spectacle lenses had no significant effect on LOA compared to standard single vision spectacle lenses, indicating no differential impact on accommodative response over the short period of lens wear tested.
PubMed: 38711574
DOI: 10.2147/OPTH.S453790 -
Archivos de La Sociedad Espanola de... Apr 2024Presbyopia affects between 1.7 and 2 billion people worldwide. Presbyopia significantly impacts productivity and quality of life in both developed and developing... (Review)
Review
Presbyopia affects between 1.7 and 2 billion people worldwide. Presbyopia significantly impacts productivity and quality of life in both developed and developing countries. During accommodation, the human eye changes its dioptric power by altering the shape of the lens, but the exact nature of this change has not been fully explained. Recently, topical treatments have been marketed for the treatment of presbyopia and others are under investigation. In order to prepare a review of these novel therapies, we searched the major biomedical search engines. We found 15 randomized clinical trials and 12 reviews that met our review criteria. There are two different strategies for this purpose, the pinhole effect that increases depth of focus and "crystalline lens relaxation" for which parasympathetic mimetics and lens oxidation intermediates have been used. The results are generally favorable in terms of improvement of near visual acuity, although the follow-up period of the studies is short. These are novel strategies in the early stages of research that could be useful in the treatment of presbyopia.
PubMed: 38663714
DOI: 10.1016/j.oftale.2024.04.008 -
Klinische Monatsblatter Fur... Apr 2024Performance and symptoms in completing a visual search task on a PC monitor and using a head-mounted display (HMD) were compared for different viewing conditions and...
BACKGROUND
Performance and symptoms in completing a visual search task on a PC monitor and using a head-mounted display (HMD) were compared for different viewing conditions and between users of different ages.
PATIENTS AND METHODS
Twenty-three young (M = 30 y, SD = 7 y) and 23 older (M = 52 y, SD = 5 y) participants performed a visual search task presented on a PC monitor. The task was repeated using an HMD for a near and a far virtual viewing distance. Reaction times (RT), detection sensitivity (d'), and symptoms were recorded for the three different viewing conditions.
RESULTS
RT and d' were not affected by the viewing condition (p > 0.05). In contrast, symptoms significantly depended on the viewing condition but were, in part, not significantly affected by age. It is interesting to note that although not significant, young participants reported more ocular symptoms than older participants in the near vision task carried out using the HMD.
DISCUSSION
HMD increases visual symptoms. However, HMD could be, in part, a remedy to problems when using visual aids for near work, in particular for presbyopes.
Topics: Humans; Presbyopia; Male; Virtual Reality; Female; Adult; Middle Aged; Accommodation, Ocular; Convergence, Ocular; Young Adult; Reaction Time
PubMed: 38653312
DOI: 10.1055/a-2237-2840 -
Cerebral Cortex (New York, N.Y. : 1991) Apr 2024The brain networks for the first (L1) and second (L2) languages are dynamically formed in the bilingual brain. This study delves into the neural mechanisms associated... (Comparative Study)
Comparative Study
The brain networks for the first (L1) and second (L2) languages are dynamically formed in the bilingual brain. This study delves into the neural mechanisms associated with logographic-logographic bilingualism, where both languages employ visually complex and conceptually rich logographic scripts. Using functional Magnetic Resonance Imaging, we examined the brain activity of Chinese-Japanese bilinguals and Japanese-Chinese bilinguals as they engaged in rhyming tasks with Chinese characters and Japanese Kanji. Results showed that Japanese-Chinese bilinguals processed both languages using common brain areas, demonstrating an assimilation pattern, whereas Chinese-Japanese bilinguals recruited additional neural regions in the left lateral prefrontal cortex for processing Japanese Kanji, reflecting their accommodation to the higher phonological complexity of L2. In addition, Japanese speakers relied more on the phonological processing route, while Chinese speakers favored visual form analysis for both languages, indicating differing neural strategy preferences between the 2 bilingual groups. Moreover, multivariate pattern analysis demonstrated that, despite the considerable neural overlap, each bilingual group formed distinguishable neural representations for each language. These findings highlight the brain's capacity for neural adaptability and specificity when processing complex logographic languages, enriching our understanding of the neural underpinnings supporting bilingual language processing.
Topics: Humans; Multilingualism; Male; Female; Magnetic Resonance Imaging; Young Adult; Brain; Brain Mapping; Adult; Phonetics; Reading; Language; Japan
PubMed: 38652552
DOI: 10.1093/cercor/bhae150 -
Contact Lens & Anterior Eye : the... Apr 2024It is important to be able to measure the range of clear focus in clinical practice to advise on presbyopia correction techniques and to optimise the correction power....
It is important to be able to measure the range of clear focus in clinical practice to advise on presbyopia correction techniques and to optimise the correction power. Both subjective and objective techniques are necessary: subjective techniques (such as patient reported outcome questionnaires and defocus curves) assess the impact of presbyopia on a patient and how the combination of residual objective accommodation and their natural DoF work for them; objective techniques (such as autorefraction, corneal topography and lens imaging) allow the clinician to understand how well a technique is working optically and whether it is the right choice or how adjustments can be made to optimise performance. Techniques to assess visual performance and adverse effects must be carefully conducted to gain a reliable end-point, considering the target size, contrast and illumination. Objective techniques are generally more reliable, can help to explain unexpected subjective results and imaging can be a powerful communication tool with patients. A clear diagnosis, excluding factors such as binocular vision issues or digital eye strain that can also cause similar symptoms, is critical for the patient to understand and adapt to presbyopia. Some corrective options are more permanent, such as implanted inlays / intraocular lenses or laser refractive surgery, so the optics can be trialled with contact lenses in advance (including differences between the eyes) to better communicate with the patient how the optics will work for them so they can make an informed choice.
PubMed: 38641525
DOI: 10.1016/j.clae.2024.102156 -
Journal of Ophthalmic & Vision Research 2024The present study sets out to investigate the effect of cyclopentolate-induced cycloplegia on distance and near deviation and the accommodative convergence/accommodation...
PURPOSE
The present study sets out to investigate the effect of cyclopentolate-induced cycloplegia on distance and near deviation and the accommodative convergence/accommodation (AC/A) ratio.
METHODS
This prospective study was performed on 30 subjects. The inclusion criteria included a lack of any active ocular pathology and systemic diseases, no history of ocular surgery, and nonuse of various medications. Refraction, near and distance deviation were measured for all subjects, and the same examinations were repeated after the administration of two drops of cyclopentolate 1% to both eyes.
RESULTS
The obtained data from 30 subjects, including 19 males, with a mean age of 22.53 1.74 years were analyzed. The mean SD of near deviation in dry and cycloplegic conditions were -6.9 8.1 and +6.4 9.1 prism diopters, respectively, which were statistically significant ( 0.001). Distance deviation in cycloplegic conditions demonstrated an average difference of 0.8 prism diopters, compared to dry conditions ( 0.001). AC/A ratios were 4.7 2.5 and 9.7 3.9 (Δ/D) in non-cycloplegic and cycloplegic conditions, respectively, which was a statistically significant difference ( 0.001). The multiple regression indicated that among all under study variables, refraction (B coefficient: -2.4; 0.001) and near pre-cycloplegic deviation (B coefficient: 0.56; 0.001) were significantly associated with post-cycloplegic near deviation.
CONCLUSION
The results of this study indicated that cycloplegia causes a considerable esophoric shift in near deviation and a negligible esophoric shift in distance deviation. As a result, the AC/A ratio demonstrated a significant increase due to unequal changes in near and distance deviation.
PubMed: 38638622
DOI: 10.18502/jovr.v19i1.15442 -
PloS One 2024To determine the effect of sex as a risk factor regarding presbyopia.
PURPOSE
To determine the effect of sex as a risk factor regarding presbyopia.
METHODS
Maximum accommodation was pharmacologically induced (40% cabachol corneal iontophoresis) in 97 rhesus monkeys (49 males and 48 females) ranging in age from 8 to 36 years old. Accommodation was measured by Hartinger coincidence refractometry.
RESULTS
Accommodative amplitude measured refractometrically decreased with age, and the rate of change was not different between males and females (p = 0.827).
CONCLUSIONS
Presbyopia is essentially sex neutral, and no one is spared. There may be modest variations between different populations for various reasons, but essentially it is monotonously predictable. At present there is no biological therapeutic.
Topics: Male; Animals; Female; Macaca mulatta; Presbyopia; Accommodation, Ocular; Aging; Lens, Crystalline
PubMed: 38635668
DOI: 10.1371/journal.pone.0300476 -
Contact Lens & Anterior Eye : the... Jun 2024To determine the relationship between changes in accommodative and binocular function with myopia progression in myopic children over a two-year follow-up period, and to...
PURPOSE
To determine the relationship between changes in accommodative and binocular function with myopia progression in myopic children over a two-year follow-up period, and to determine when changes in visual functions stabilized after switching from spectacles to orthokeratology (Ortho-K).
METHODS
This prospective, self-controlled study followed thirty-six participants (aged 8-14 years) for two years after they switched from spectacles to Ortho-K. Accommodative and binocular function were assessed prior to and 1, 3, 6, 12, 18 and 24 months after commencing Ortho-K. Measurements included accommodative amplitude, accommodative response, accommodative facility, accommodative convergence/accommodation (AC/A), ocular alignment, positive relative accommodation (PRA), negative relative accommodation (NRA), horizontal vergence range, reading ability and stereoacuity. Myopia progression was quantified by the change in axial length.
RESULTS
Ocular alignment, monocular and binocular accommodative facility, and PRA stabilized after 1 month. The distance blur point in the convergence range, the distance break and recovery point in the divergence range, accommodative amplitude, calculated AC/A, stereoacuity and reading ability stabilized within 6 months. After two years of Ortho-K, NRA significantly increased (p = 0.044), while it showed no significant difference after one-year of lens wear (p = 0.49). The distance break point in the convergence range showed no significant difference (p = 0.20), but significantly decreased after one-year (p = 0.005). There were no significant correlations between the change in axial length with changes in accommodative or binocular function (p > 0.05).
CONCLUSION
Accommodative and binocular function changed significantly after switching from spectacles to Ortho-K and most of the parameters stabilized within the first 6 months. There was no association between the change in accommodative or binocular function and myopia progression.
Topics: Humans; Child; Accommodation, Ocular; Male; Orthokeratologic Procedures; Female; Adolescent; Vision, Binocular; Disease Progression; Myopia; Eyeglasses; Prospective Studies; Visual Acuity; Refraction, Ocular; Treatment Outcome
PubMed: 38631934
DOI: 10.1016/j.clae.2024.102171 -
Graefe's Archive For Clinical and... Apr 2024The study aims to compare morphology and location of crystalline lens between acute acquired concomitant esotropia (AACE) patients and control subjects, both before and...
PURPOSE
The study aims to compare morphology and location of crystalline lens between acute acquired concomitant esotropia (AACE) patients and control subjects, both before and after cycloplegia.
METHODS
This is a prospective and observational clinical study. Morphological and locational parameters of the crystalline lens in 53 AACE patients and 32 control subjects were assessed before and after cycloplegia using CASIA2 system, which represents the latest swept-source anterior segment optical coherence tomography. Cycloplegic refraction was recorded by administering 1% atropine in patients younger than 12 years and 1% cyclopentolate in those > 12 years old. Morphological parameters included anterior radius of curvature (ARC), posterior radius of curvature (PRC), lens thickness (LTH), and equivalent diameter of lens (LED). Locational parameters comprised lens decentration (LD) and lens tilt (LT). Comparison of these parameters before and after cycloplegia were conducted between AACE and controls. Additionally, the study analyzed and compared the changes in these parameter post-cycloplegia.
RESULTS
Our findings suggest no significant difference in morphological parameters including ARC, PRC, LTH and LED between AACE patients and controls before or after cycloplegia. However, 2D-modeling data in the 0° meridian revealed that variation post-cycloplegia of LD (lens shift) in right eyes was different in AACE patients, measuring - 0.03(0.08) [median(interquartile range)] which was significantly distinct from the control group, exhibiting a measurement of 0.01(0.06) (z = - 2.373, p = 0.018). In left eyes, a similar trend was observed with lens shift in the 0° meridian being 0.02(0.06) in AACE, significantly differing from control group's measurement of - 0.02(0.08) (z = - 2.809, p = 0.005). Further, correlation analysis revealed that larger temporal shift of lens was associated with greater changes in ARC (r = 0.294, p = 0.006) and LTH (r = - 0.230, p = 0.031).
CONCLUSIONS
The morphological features of the crystalline lens were similar in AACE patients and controls; however, the change of lens location by cycloplegia was observed only in AACE patients, suggesting an association with excessive accommodation.
PubMed: 38625449
DOI: 10.1007/s00417-024-06484-z