The success rate of wearing bifocals in children with Down's syndrome

Purpose:  Accommodation is reduced in approximately 75% of children with Down's syndrome (DS) compared to their peers (Woodhouse et al ., 1993). A study by Stewart et al . (2005) showed that bifocals improve focusing on near targets and they are currently prescribed regularly. The study also showed that wearing bifocals improved the children's own accommodative ability over time. The aim of this study is to evaluate the success of wearing bifocals in improving accommodation.
Methods:  Clinical records of 37 children from the Cardiff University Down's Syndrome Vision Research Unit, who were prescribed bifocals, were reviewed. Their accommodation, using dynamic retinoscopy at 10, 16.7 and 25 cm, was noted before wearing the bifocals and during either their latest visit or when they stopped using bifocals. An accommodative lag of up to and including 0.75D at two or more testing distances is considered accurate (McClelland and Saunders, 2004).
Results:  The accommodative ability of 23 out of 37 (62.16%) of the children had improved (through the distance part of the lens) after using the bifocals for an average of 29.38 months. Thirteen out of those 23 had accurate accommodation, one third of the overall number of children, without the use of bifocals. These 13 children have returned, or will shortly return, to single vision spectacles.
Conclusions:  Using bifocals not only improves the children's accuracy of focusing on near objects through the bifocals, but also 'trains' their accommodative ability, with a success rate of 62.16% so far. For some children at least, bifocal wear can be a temporary management strategy.     

The efficacy of SimulVue and Unilens RGP aspheric bifocal contact lenses in the treatment of esotropia associated with a high accommodative convergence/accommodation ratio.

PURPOSE: This was a prospective study assessing the efficacy of the SimulVue bifocal contact lens and the Unilens RGP aspheric multifocal contact lens (Unilens, Largo, Fla.) in the treatment of high accommodative convergence/accommodation (AC/A) esotropia in an adolescent and postadolescent population. METHODS: Those patients meeting the inclusion criteria were fit with contact lenses with use of full cycloplegic refraction and later retested by an examiner masked to the previous binocular status. Particular attention was given to the sensory status and the motor fusion of each patient in their bifocal spectacles and then in their bifocal contact lenses. All patients were followed up for at least 6 months after the contact lenses were fitted. RESULTS: Five of the six patients demonstrated larger angles of esophoria or tropia at near with the contact lenses than with bifocal spectacles. The only patient who maintained excellent stereopsis in bifocal contact lenses was the one who normalized her AC/A ratio during this study and no longer required a bifocal in her spectacle correction for fusion. The two patients who initially had no stereopsis but good alignment in spectacle correction had a large esotropia at near fixation with bifocal contact lenses. CONCLUSIONS: The SimulVue and Unilens RGP aspheric bifocal contact lenses did not adequately treat adolescent patients who had esotropia associated with a high AC/A ratio.     

Contrast sensitivity measurements with the Echelon diffractive bifocal contact lens as compared to bifocal spectacles.

We examined the contrast sensitivity function of presbyopic subjects wearing the Hydron Echelon diffractive bifocal contact lens. Contrast sensitivity with the Echelon lens was compared to contrast sensitivity with bifocal spectacle correction. Each eye was tested for near and distance vision with the Echelon contact lens and with spectacle correction. Most subjects achieved a visual acuity of 20/20 with the Echelon lens; however, on average, contrast sensitivity was found to be significantly decreased with the contact lens as compared to spectacles for both distance and near vision. The largest decrease in contrast sensitivity was seen for mid-range spatial frequencies (4 to 16 cycles/degree). Although most subjects experienced a significant decrease in contrast sensitivity, two experienced only small decreases with the Echelon lens. Only one subject who met entry criteria reported that vision was as good with the Echelon lens as with spectacles. The decreased contrast sensitivity may result from contact lens decentration as well as inherent optical characteristics of the Echelon lens.     

Comparative visual performance of three presbyopic contact lens corrections.

We compared the visual performance of a soft diffractive (DIFF) bifocal contact lens, a near center (CN) concentric bifocal design, and monovision (MV), using a comprehensive vision testing protocol. Fifteen presbyopic subjects who were successfully wearing DIFF bifocal contact lenses participated in the study. Of the three systems tested, MV provided best visual acuity at distance and near; less than one line of acuity was lost relative to best spectacle acuity under all lighting and contrast conditions, and there was less disturbance of a point source of light. Both bifocal corrections gave similar visual acuity performance, with more lines of acuity lost relative to spectacles at near compared to distance. However, the concentric bifocal induced more ghosting at near than the other two systems. Stereopsis was compromised at distance with MV correction, but all systems performed worse than spectacles at near. An understanding of the strengths and weaknesses of presbyopic contact lens options allows the clinician to improve management of the presbyope who wishes to wear contact lenses.     

角膜塑形镜对近视性屈光参差儿童双眼视功能的影响

目的　探究角膜塑形镜（OK镜）对近视性屈光参差儿童双眼视功能的影响。方法　收集2018年至2019年于北京大学第三医院眼科视光中心就诊的60例近视性屈光参差儿童资料,随机分为OK组（配戴OK镜）和SP组（配戴普通框架眼镜）,每组各30例。基线时（配戴OK镜或框架眼镜前）和戴镜后6个月、12个月时,分别对受试儿童进行远距斜视度、远距融合范围、远近距立体视的检查。比较OK组和SP组儿童双眼视功能参数的差异,以及两组儿童双眼视功能参数随戴镜时间的变化情况。结果　与基线时相比,戴镜后6个月、12个月时,OK组儿童的远距融合范围、远距集合范围显著减小,近距立体视显著提高（均为P<0.05）,而远距斜视度、远距融合点、远距散开范围、远距立体视差异均无统计学意义（均为P>0.05）。与基线时相比,戴镜后6个月、12个月时,SP组儿童的近距立体视均显著提高（均为P<0.05）,而远距斜视度、远距融合点、远距融合范围、远距集合范围、远距散开范围、远距立体视差异均无统计学意义（均为P>0.05）。OK组和SP组儿童基线时和戴镜后6个月时的远距斜视度、远距融合范围、远距融合点、远距集合范围、远近距立体视差异均无统计学意义（均为P>0.05）。戴镜后12个月时,OK组儿童的远近距立体视均优于SP组（均为P<0.05）,而两组儿童其余指标差异均无统计学意义（均为P>0.05）。结论　近视性屈光参差儿童配戴OK镜后,远距融合范围减小,近距立体视提高。与框架眼镜相比,OK镜改善近视性屈光参差儿童远近距立体视的作用更好。     

Tangent Streak RGP bifocal contact lenses in the treatment of accommodative esotropia with high AC/A ratio.

Patients with the diagnosis of high accommodative convergence/accommodation (AC/A) ratio, accommodative esotropia traditionally have been fit with bifocal spectacles. For cosmetic reasons, however, many patients prefer non-spectacle correction. Orthoptics, miotics, contact lenses, and surgery have been used as alternatives. We describe the treatment of three patients with the Tangent Streak bifocal rigid gas permeable (RGP) contact lens in which functional control of the patient's deviation was attained. Tangent Streak RGP bifocal contact lenses offer an acceptable alternative to bifocal spectacles, surgery, miotics, or orthoptics in the treatment of accommodative esotropia with high AC/A ratio.     

Soft bifocal contact lenses for patients with nearpoint asthenopia

Bifocal contact lenses have generally been considered solely for the presbyopic population. However, pre-presbyopic individuals with accommodative or vergence disorders who respond favorably to plus lenses at near may be good candidates for bifocal contact lenses. A group of ten non-presbyopic patients who manifest accommodative dysfunctions or near point esophoria were fit with the Ciba BI-SOFT contact lenses. Nearpoint accommodative and vergence findings were evaluated through both near point plus spectacle lenses and the bifocal soft lenses. Results indicate that the BI-SOFT bifocal contact lens was effective in changing the near point visual posture. However, poor distance vision acuity due to ghost images reduced the subjective success rate of the BI-SOFT lens on this non-presbyopic population.     

青少年近视眼的急斜和正透镜对隐斜的影响

目的 研究青少年近视眼的隐斜和正透镜对隐斜的影响。方法 用隐斜计测定１５１例不同屈光度青少年在裸眼,戴矫正镜片和矫正镜片再加＋１．５０Ｄ球镜条件下看近的隐斜度,结果近视各组倾向外隐斜,戴矫正镜片时外隐斜明显减少,再加正透镜后外隐斜又明显增加,结论 从调节和集合平衡的观点出发,青少年近视眼以戴矫正眼镜为好,正透镜的应用要采取慎重态度。     

Peripheral visual acuity with monovision and other contact lens corrections for presbyopia

We have conducted two experiments to investigate the effect of monovision and other contact lens corrections for presbyopia upon peripheral visual acuity. In the first study, we measured binocular peripheral visual acuity using Landolt rings with seven subjects wearing a monovision correction. The Landolt rings were presented at eccentricities of 10, 20, 40, and 70 degrees on each side of the subject, with near additions of +1.50 D, +2.50 D, and no addition. We found no significant effect of monovision correction on peripheral visual acuity. In the second experiment we measured the peripheral visual acuity of 11 presbyopic subjects wearing distance contact lenses with lookover spectacles, soft progressive bifocal contact lenses, soft concentric bifocal contact lenses, monovision contact lenses, modified monovision contact lenses, and hard bifocal contact lenses using Koenig bar targets. There were no significant differences in peripheral visual acuity between any of the contact lens corrections for presbyopia.     

Comparison of visual outcomes with implantation of trifocal versus bifocal intraocular lens after phacoemulsification: a Meta-analysis

AIM: To compare a trifocal intraocular lens (IOL) and a bifocal IOL implantation in improving visual function after cataract surgery. METHODS: Eligible literatures were systematically searched through EMBASE and PubMed databases. The inclusion criteria were prospective comparative clinical trials on cataract surgery comparing trifocal IOL with bifocal IOL implantation that assessed visual acuity, contrast sensitivity and subjective vision quality. The effects were computed as standardized mean differences and pooled using fixed-effect or random-effect models. RESULTS: Four prospective randomized controlled trials (RCTs) and five cohorts provided data were included by a systematic review, comprising 265 eyes implanted with trifocal IOLs and 264 eyes implanted with bifocal IOLs. Monocular distance visual acuity (VA) showed a statistically significant but small difference that favored trifocal IOLs (MD=-0.06; 95%CI, -0.10 to -0.02; Z=2.90, P=0.004 for uncorrected distance VA, and MD= -0.02; 95%CI, -0.03 to -0.00; Z=2.02, P=0.04 for corrected distance VA), but the data did not suggest that the effect of trifocal IOL implantation would clinically outperform bifocal IOL implantation. There was no significant difference in monocular near VA (MD=-0.01; 95%CI, -0.07 to 0.04; Z=0.42, P=0.68 for distance-corrected near VA, and MD=-0.01; 95%CI, -0.06 to 0.03; Z=0.55, P=0.58 for corrected near VA) or refraction between two groups. Contrast sensitivity and subjective visual quality had no conclusive results. CONCLUSION: All results indicate that trifocal IOL and bifocal IOL had similar levels of monocular distance and near VA.     

Short term responses to soft contact lens corrections for presbyopia

Eleven subjects were each fitted with five different soft contact lens corrections for presbyopia. The correction types were distance contact lenses with lookover spectacles, concentric bifocals, monovi-sion, modified monovision and progressive bifocal contact lenses. Subjects were asked to rate each contact lens correction in terms of distance, intermediate, near and peripheral vision, confidence when walking and climbing stairs, eye-hand co-ordination, performance on work tasks, vision difficulties in bright and dim ambient illumination and the correction most preferred for daily wear. There were few significant differences between ratings for the different corrections. Monovision, modified monovision and the concentric bifocal corrections were the preferred options for daily wear.     

Association between accommodative accuracy, hypermetropia, and strabismus in children with Down's syndrome.

PURPOSE: A significant proportion of children with Down's syndrome have been shown to have reduced accommodation. The purpose of this study was to investigate any association between reduced accommodation and refractive error, strabismus, visual acuity, and other ocular parameters. METHODS: Subjects were children with Down's syndrome enrolled in a longitudinal cohort to monitor visual development. Twenty-seven children with accurate accommodation were age-matched to children with reduced accommodation based on their most recent assessment for which a full, reliable data set was available. Each child was used only once for matching. Cross-sectional ocular and visual data were analyzed using chi or Fisher's exact test, or the Mann-Whitney U test for (non-normally distributed) quantitative data. RESULTS: Children with under-accommodation were statistically more likely to have moderate/high hypermetropia (> or = +3.00 D) and to be strabismic (most with esotropia). No significant difference between the groups was found for any other ocular parameters. CONCLUSIONS: This study demonstrates the marked association between under-accommodation, hypermetropia, and strabismus in children with Down's syndrome. No causal relation can be demonstrated with these data, but findings suggest that the link between under-accommodation and hypermetropia (and between accurate accommodation and emmetropia) is present in early infancy.     

Refractive bifocal intraocular lens and pupillary diameter.

To assess the relationship between pupillary diameter and focusing for distance and near vision with the refractive bifocal intraocular lens (IOL), we studied visual acuity for far and near distance, near point, and depth of focus with normal pupillary movements and after pharmacological miosis and mydriasis (pilocarpine 2% and phenylephrine 10% eyedrops, respectively) in 20 patients implanted with an IOLAB refractive bifocal IOL. Pharmacological miosis and mydriasis did not change far and near visual acuity values from the values with normal pupillary diameter. After pharmacological miosis, the near point position and the width of the depth of focus were unchanged. After pharmacological mydriasis, near point distance was unchanged but depth of focus dropped in a statistically significant manner (P < .01). We concluded that the pupillary diameter alone cannot produce distance or near vision focusing. The choice depends on the brain's preference. Pupillary diameter increases the quality of vision through the blur circles mechanism.     

青少年近视眼的隐斜和正透镜对隐斜的影响

目的研究青少年近视眼的隐斜和正透镜对隐斜的影响。方法用隐斜计测定１５１例不同屈光度青少年在裸眼、戴矫正镜片和矫正镜片再加＋１．５０Ｄ球镜条件下看近的隐斜度。结果近视各组倾向外隐斜，戴矫正镜片时外隐斜明显减少，再加正透镜后外隐斜又明显增加。结论从调节和集合平衡的观点出发，青少年近视眼以戴矫正眼镜为好，正透镜的应用要采取慎重态度。     

Facial characteristics in children with Down's syndrome and spectacle fitting

Significant refractive error is very common among children with Down's syndrome so the requirement for spectacles for this group is high. The aim of this study was to measure the facial characteristics of children with Down's syndrome and to compare them with two previous studies which have aided the design of children's spectacle frames. The study was carried out in two schools in South Wales, measuring 20 children between the ages of 3.6 and 14.4 years. The results show that between the ages of 7 and 14 years, facial characteristics of children with Down s syndrome do not change with age and rarely coincide with those of other children, either of a similar age or younger. Thus children with Down's syndrome cannot be fitted satisfactorily with conventional children's frames, and it would be desirable for a specially designed range of frames to be made available.     

Bifocal soft contact lenses as a possible myopia control treatment: a case report involving identical twins

Background: Several studies have suggested that bifocal and progressive spectacles can reduce progression of myopia in esophoric children. This study compared myopic progression with bifocal (BSCL) and single vision soft contact lenses (SVSCL) in identical twins with near point esophoria. Methods: Two 12‐year‐old myopic girls were randomly assigned to wear either BSCL or SVSCL for one year using a double‐masked design. Both twins then wore BSCLs for another year. Ocular measurements included cycloplegic and manifest refractions, corneal curvature and axial length. Distance and near phorias were measured through distance corrections and near associated phorias, with both types of contact lenses. Results: Through their SVSCLs, both children exhibited near associated esophorias, which were neutralised by the BSCLs. The child wearing SVSCLs over the first year showed significant myopic progression, increasing ‐1.19 D (binocular average), while the child wearing BSCLs showed no progression (+0.13 D). The latter child showed limited progression (‐0.28 D) over the second year, while switching from SVSCLs to BSCLs arrested progression in the other child (+0.44 D after one year). Axial length data were consistent with the refractive findings; the child exhibiting more myopia at the end of the first 12 months of the study had longer eyes (by 0.64 mm) than her sister, although their corneas also had steepened more (by 0.44 D compared to 0.18 D). The children showed similar, small increases in eye size over the second year when both wore BSCLs (binocular averages: 0.05, 0.09 mm, respectively). Conclusion: The apparent inhibitory effect of BSCLs on myopic progression reported in this twin study argues for further study of their efficacy as a control treatment for myopes with near esophoria.     

Visual performance of a multi-zone bifocal and a progressive multifocal contact lens.

PURPOSE: This study measured the relative visual performance of two planned-replacement soft contact lenses for presbyopic correction: a multi-zone bifocal (ACUVUE, Johnson & Johnson Vision Care, Jacksonville, FL) contact lens and a progressive multifocal (Focus Progressives, CIBA Vision, Duluth, GA) contact lens. METHODS: This was a randomized, double-masked, non-dispensing cross-over study. Visual performance was evaluated by log of minimal angle of resolution (LogMAR) measurement of visual acuity (VA) under a representative range of luminances (distance 250 candela[cd]/m2 and 2.5 cd/m2, near 250 cd/m2 and 50 cd/m2) and contrasts (90% and 10%). The 45 presbyopic subjects were equally distributed in three subgroups according to spectacle addition: low presbyopia (+0.75D to +1.25D); medium presbyopia (+ 1.50D to + 1.75D); and high presbyopia (+2.00 to +2.50D). RESULTS: Statistically significant differences were found in overall distance VA (P<0.001; average of four luminance-contrast combinations) and low-luminance distance VA (P=0.004), which, in both cases, favored the multi-zone bifocal lens design. For low presbyopes, the multi-zone bifocal design produced a significantly better visual performance (P=0.004) than did the progressive multifocal. Overall near VA was also significantly better (P<0.001) with the multi-zone bifocal lens. Differences in near VA were particularly marked in high-luminance conditions (high and low contrasts combined) and were statistically significant for all three presbyopic subgroups. CONCLUSIONS: Visual acuity performance with the multi-zone bifocal was superior overall to that achieved with the progressive multifocal design. This study suggests that having only one addition is detrimental to performance with the progressive multifocal lens, particularly for low presbyopes.     

Effects of wearing yellow spectacles on visual skills, reading speed, and visual symptoms in children with reading difficulties

Background

Possible beneficial effects of yellow-tinted spectacle lenses on binocular vision, accommodation, oculomotor scanning, reading speed and visual symptoms were assessed in children with reading difficulties.

Methods

A longitudinal prospective study was performed in 82 non-dyslexic children with reading difficulties in grades 3–6 (aged 9–11 years) from 11 elementary schools in Madrid (Spain). The children were randomly assigned to two groups: a treatment (n?=?46) and a without-treatment group (n?=?36). Children in the treatment group wore yellow spectacle lenses with best correction if necessary over 3 months (in school and at home). The tests were first undertaken without the yellow filter. With best spectacle correction in each subject, measurements were made of: distance and near horizontal heterophoria, distance and near horizontal fusional vergence ranges, the accommodative convergence/accommodation (AC/A) ratio, near point of convergence (NPC), stereoacuity, negative relative accommodation (NRA) and positive relative accommodation (PRA), monocular accommodative amplitude (MAA), binocular accommodative facility (BAF), oculomotor scanning, and reading speed (words per minute). The Convergence Insufficiency Symptom Survey (CISS) questionnaire was completed by all children. After the 3-month period, measurements were repeated with the yellow lenses (treatment group) or without the yellow lenses (without-treatment group) but with refractive correction if needed.

Results

Over the 3 months, the two groups showed similar mean changes in the variables used to assess binocular vision, accommodation, oculomotor scanning, and reading speed. However, mean relative changes in convergence insufficiency symptoms differed significantly between the groups (p?=?0.01).

Conclusion

No effects of wearing yellow spectacles emerged on binocular vision, accommodation, oculomotor scanning, and reading speed in children with reading difficulties. The yellow filter had no effect even in children with low MAA and BAF. The reduction in visual symptoms observed in children with reading difficulties using the yellow filters was clinically insignificant.