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.     

Contact lenses vs spectacles in myopes: is there any difference in accommodative and binocular function?

Background  

Theoretically, the accommodative and vergence demands are different between single-vision contact lenses and spectacle lenses. The aim of the present study was to determine whether these differences exist when these two correction methods are used in clinical practice. For this, different visual parameters that characterize the accommodative (accommodation amplitude, accommodative facility, and accommodative response) and binocular function (near and distance horizontal and vertical dissociated phorias, near and vertical associated phorias, near and distance negative and positive fusional vergence, vergence facility, near point of convergence, negative and positive relative accommodation, stimulus AC:A ratio and stereoacuity) were evaluated in a student population when their myopia was corrected with either spectacles or soft contact lenses (SCL).     

Binocular coordination of saccades in children with vertigo: dependency on the vergence state

The present study examines the quality of binocular coordination of saccades at far and near distance in 15 children with symptoms of vertigo headache and equilibrium disorders; these children show normal vestibular function but abnormal convergence eye movements (e.g., long time preparation, slow execution and poor accuracy, see ). The results show normal binocular saccade coordination at far distance, but large abnormal disconjugacy for saccades at near distance. During combined saccade-vergence movements (studied in six of these children), convergence remains abnormally slow. This supports the interpretation according to which poor binocular yoking of the saccades is linked to the reduced ability to produce fast convergence during the saccade; a learning mechanism based on rapid vergence would help to reduce the abducting-adducting asymmetry of the saccades. An alternative interpretation would be reduced learning ability for monocular adjustment of the saccade signals.     

Visual performance of two simultaneous vision multifocal contact lenses

Purpose

To evaluate and compare the visual performance of two simultaneous vision multifocal contact lenses (CLs).

Methods

In this cross‐over study design 20 presbyopic subjects were fitted with two different simultaneous vision multifocal CLs (the PureVision Multifocal Low Add and Acuvue Oasys for Presbyopia) in random order. After 1 month, binocular distance visual acuity (BDVA) under photopic (85 cd/m²) and mesopic (3 cd/m²) conditions, binocular near visual acuity (BNVA), binocular distance contrast sensitivity function (CSF) under photopic and mesopic conditions, binocular near CSF and defocus curve were measured. Subjects were then refitted with the alternative correction and the procedure was repeated.

Results

Mean BDVA under photopic conditions was similar for the Acuvue Oasys for Presbyopia and PureVision Multifocal Low Add: 0.01 ± 0.08 and 0.00 ± 0.08 logMAR, respectively (P = 0.45). Under mesopic conditions the values of BDVA were 0.20 ± 0.58 and 0.11 ± 0.09 logMAR, respectively (P = 0.005). Mean BNVA was 0.20 ± 0.05 and 0.15 ± 0.08 logMAR for the Acuvue Oasys and PureVision Low Add, respectively (P = 0.06). Binocular distance CSF testing revealed no statistically significant differences between lenses under photopic, mesopic or near conditions. Both lenses provided a comparable intermediate visual acuity.

Conclusions

Both simultaneous vision multifocal CLs provided adequate distance visual quality under photopic and mesopic conditions, and better visual acuity was provided under mesopic conditions for the Purevision lens. Both lenses provided adequate visual performance at intermediate distance, but the near visual acuity appears to be insufficient for early presbyopes who require a moderately demanding near visual quality.     

Vergence and accommodation responses in the control of intermittent exotropia

Purpose

Individuals with different types of intermittent exotropia (IXT) may use neurally coupled accommodation and vergence responses differently from those without exotropia to achieve eye alignment. This study examined the relationship between simultaneously recorded accommodation and vergence responses in children and young adults with a range of types of IXT while aligned and deviated.

Methods

Responses of 29 participants with IXT (4–31 years) and 24 age-matched controls were recorded using simultaneous eye-tracking and eccentric photorefraction while they watched a movie in binocular or monocular viewing at varying viewing distances. Gradient response AC/A ratios and fusional vergence ranges were also assessed. Eight participants had divergence or pseudo-divergence excess type IXT, 5 had convergence insufficiency and 16 had basic IXT.

Results

Control and IXT participants accommodated similarly both in monocular and binocular-aligned conditions to visual targets at 80 and 33 cm. When deviated in binocular viewing, most participants with IXT exhibited changes in accommodation <0.5D relative to alignment. Gradient response AC/A ratios were similar for control [0.56 MA/D (IQR: 0.51 MA/D)] and IXT participants [0.42 MA/D (0.54 MA/D); p  = 0.60]. IXT participants showed larger vergence to accommodation ratios with changes from distance to near fixation [1.19 MA/D (1.45 MA/D)] than control participants [0.78 MA/D (0.60 MA/D); p = 0.02], especially among IXT participants with divergence or pseudo-divergence excess. Participants with IXT exhibited typical fusional divergence ranges beyond their dissociated position [8.86 Δ (7.10 Δ)] and typical fusional convergence ranges from alignment [18 Δ (15.75 Δ)].

Conclusions

This study suggests that control of IXT is typically neither driven by accommodative convergence alone nor associated with over-accommodation secondary to fusional convergence efforts. These simultaneous measurements confirmed that proximal vergence contributed significantly to IXT control, particularly for divergence or pseudo-divergence excess type IXT. For IXT participants in this study, achieving eye alignment did not conflict with having clear vision.     

The minimum test battery to screen for binocular vision anomalies: report 3 of the BAND study

Purpose

This study aims to report the minimum test battery needed to screen non‐strabismic binocular vision anomalies (NSBVAs) in a community set‐up. When large numbers are to be screened we aim to identify the most useful test battery when there is no opportunity for a more comprehensive and time‐consuming clinical examination.

Methods

The prevalence estimates and normative data for binocular vision parameters were estimated from the Binocular Vision Anomalies and Normative Data (BAND) study, following which cut‐off estimates and receiver operating characteristic curves to identify the minimum test battery have been plotted. In the receiver operating characteristic phase of the study, children between nine and 17 years of age were screened in two schools in the rural arm using the minimum test battery, and the prevalence estimates with the minimum test battery were found.

Results

Receiver operating characteristic analyses revealed that near point of convergence with penlight and red filter (> 7.5 cm), monocular accommodative facility (< 10 cycles per minute), and the difference between near and distance phoria (> 1.25 prism dioptres) were significant factors with cut‐off values for best sensitivity and specificity. This minimum test battery was applied to a cohort of 305 children. The mean (standard deviation) age of the subjects was 12.7 (two) years with 121 males and 184 females. Using the minimum battery of tests obtained through the receiver operating characteristic analyses, the prevalence of NSBVAs was found to be 26 per cent. Near point of convergence with penlight and red filter > 10 cm was found to have the highest sensitivity (80 per cent) and specificity (73 per cent) for the diagnosis of convergence insufficiency. For the diagnosis of accommodative infacility, monocular accommodative facility with a cut‐off of less than seven cycles per minute was the best predictor for screening (92 per cent sensitivity and 90 per cent specificity).

Conclusion

The minimum test battery of near point of convergence with penlight and red filter, difference between distance and near phoria, and monocular accommodative facility yield good sensitivity and specificity for diagnosis of NSBVAs in a community set‐up.

     

Latency of saccades, vergence, and combined movements in children with early onset convergent or divergent strabismus

The goal of this study was to examine latency of horizontal eye movements in the natural space (saccades, vergence, and combined saccade-vergence movements) in children with early onset convergent or divergent strabismus. Ten children were tested (8-11 years old): three with divergent strabismus, seven with convergent strabismus. A paradigm was used to elicit pure lateral saccades at far and near distance, pure vergence (convergence and divergence) and saccades combined with vergence movements. Horizontal eye movements from both eyes were recorded simultaneously by a photoelectric device (Oculometer, Dr. Bouis). The latency of saccades (at far and near distance), of vergence (convergence and divergence), and of combined movements greatly varies among subjects and has tendency to be longer than that observed in normal children of matched age, however, these differences reach significance in only a few cases. Children with divergent strabismus and residual gross binocular vision show abnormally longer vergence latencies than children with convergent strabismus without binocular vision. The initiation of combined movements does not show a dominant pattern, such as preceding vergence, as is found in normal children. Finally, strabismus surgery has no major effect on latencies. We conclude that there is no overall deficiency in latencies of eye movements in 3D space in children with early onset strabismus. Most likely, monocular visual input can be efficient as normal binocular vision for vergence movements. In a few subjects with divergent strabismus and fragile, intermittent binocular vision, latencies can be abnormally long, just because of the fragile binocular input and/or attention effort needs to use it. The absence of a pattern of initiation similar to normal children could be due to attention and fixation capabilities.     

The Effect of Prism Adaptation on the Angle of Deviation in Convergence Excess Esotropia and Possible Consequences for Surgical Planning

Convergence excess esotropia describes a heterophoria with binocular single vision (BSV) on distance viewing that becomes esotropic on accommodation upon near fixation. Prism adaptation test (PAT) is a procedure routinely used to reveal the maximum angle of deviation preoperatively for many types of strabismus and has been shown to improve surgical outcomes; however, it is not conventionally used for convergence excess esotropia.

Aim: This study compares the angle of deviation at 1/3 m and 6 m before and after prism adaptation in subjects with convergence excess esotropia to determine if a masked distance angle of deviation can be demonstrated similar to the masked near angle of deviation in some intermittent exotropes. Surgical results are reported.

Results: Fifty-eight children with convergence excess esotropia were prescribed prism adaptation prior to strabismus surgery and 49 met the inclusion criteria. A median increase in the angle of deviation of 20 prism dioptres (PD) was seen at both 1/3 m and 6 m following PAT. These changes were statistically significant (p < 0.001) at both distances. Following one surgical procedure, 83.6% were fully binocular postoperatively.

Conclusion: Prism adaptation frequently reveals an otherwise masked large distance angle of deviation in convergence excess esotropia. Convergence excess esotropia can be subdivided into two categories: true and simulated. Those with true convergence excess exhibit a manifest convergent strabismus when viewing a close object and a small, well-controlled latent strabismus upon fixation of a distant object. Those with simulated convergence excess have a comparable near deviation to those with true convergence excess but can be shown to have a distance deviation that approaches the size of the near strabismus once the normal fusional mechanisms are disrupted by a period of prism adaptation.     

Visual skills of poor readers in high school.

BACKGROUND: Prior findings suggest that poor readers tend to have poor visual skills, but few reports give full frequency distributions of skill variables, and little data are available for adolescents. METHODS: Visual skills and visual acuity were measured in 461 students (average age 15.4 years) in 4 California high schools within the same school district. Participating students had been identified by their schools as poor readers. Standard optometric tests and published criteria for "adequate" or "weak" visual skills were used. RESULTS: In this sample, 80% of the students were found to be inadequate or weak in 1 or more of the following visual skills: binocular fusion ranges at near, accommodative facility, and convergence near point. More students were deficient in binocular fusion range than in either accommodative function or near point of convergence. In contrast, only 17% had deficient visual acuity--20/40 or worse in 1 eye--the standard model of deficiency for school vision screenings. CONCLUSION: The results support and extend previous studies showing that large numbers of poor readers in high school may be at high risk for visual skills dysfunction.     

Sighting ocular dominance magnitude varies with test distance

Background

Ocular dominance can be defined as the preference of an individual for viewing with one eye over the other for particular visual tasks. It is relevant to monovision contact lens wear, cataract surgery and sports vision. Clinically, the measurement of ocular dominance is typically done at an arbitrary distance using a sighting test, such as the hole‐in‐card method that has a binary outcome. We investigated the effect of test distance on ocular dominance measured using a binocular sighting test that provided a continuous measurement of dominance.

Methods

Ten participants with normal binocular vision took part in this study. Their binocular sighting ocular dominance and phorias were measured at one, two, four, eight and 10 metres. During the dominance tests participants made a binocular alignment judgment and then were asked to indicate the relative alignment of each eye using a visual analogue scale as a reference.

Results

Eight participants had strong ocular dominance (five right, three left). For these participants, there was a significant increase in the magnitude of dominance with increasing test distance (p < 0.001). This could not be fully explained by changes in convergence demand. Two participants showed very weak ocular dominance across all test distances (p > 0.05), despite changes in convergence demand.

Conclusion

When ocular dominance is present, its magnitude varies significantly with test distance. This has significant implications for the accurate measurement of ocular dominance in the clinic and may reflect the neural processes that influence eye preference.

     

Subjektive und objektive Ergebnisse nach Implantation der apodisiert diffraktiven AcrySof ReSTOR

Background

Our purpose in this study was to assess the postoperative subjective and objective results after implantation of the Acrysof ReSTOR lens and to evaluate the advantages and limitations of the apodized diffractive optic design of this new multifocal intraocular lens (MIOL).

Methods

Phakoemulsification and implantation of an Acrysof ReSTOR was performed in 55 eyes of 32 patients. All patients were examined after a mean period of 7.9±1.9 months. The accuracy of lens calculation was evaluated for the Haigis, Holladay I, and SRK-T formulas. Uncorrected and corrected visual acuity for distance and for intermediate and near vision were assessed, as was stereoacuity. In addition, contrast sensitivity was tested under photopic and mesopic conditions, with and without glare. The patients were asked about dysphotic phenomena such as halos, glare or flare, and night vision using a standardized evaluation. The degree to which patients were able to manage without spectacles after the surgery was also documented.

Results

The median monocular uncorrected visual acuity (UCVA) for distance was 20/25 (LogMAR 0.05) while the binocular UCVA was 20/20 (LogMAR 0). The monocular uncorrected acuity for near vision was 20/25 (LogMAR 0.1), the binocular near visual acuitiy was 20/20 (LogMAR 0), while the intermediate monocular visual acuity was 20/50 (LogMAR 0.4) and the binocular, 20/32 (LogMAR 0.2). Contrast sensitivity was within the normal range. Dysphotic phenomena were noted by 66% of patients but were so slight as not to cause any problem at all in 59%. For close work and distance vision 84% of all patients needed no correcting glasses, while 78% did not need to use glasses for intermediate vision.

Conclusion

The Acrysof ReSTOR provides excellent uncorrected visual acuity for distance and near vision and the level of patient satisfaction achieved with it is good.     

配戴多焦点硬性角膜接触镜对近视患者双眼视功能的影响

目的：探讨多焦点设计的硬性角膜接触镜对近视患者双眼视功能的影响。

方法：自身前后对照研究。于2020-07/08在川北医学院招募近视学生15人作为试验者,试验者首先配戴框架眼镜行双眼视功能检查,然后分别配戴单焦点与多焦点硬性角膜接触镜(间隔1wk),每种镜片配戴2wk后行双眼视功能检查。采用单因素方差分析比较多焦点硬性角膜接触镜(MFRGP)、单焦点硬性角膜接触镜(SVRGP)和框架眼镜双眼视功能的差异。

结果：三种镜片立体视、远距水平隐斜、远距正融像性聚散、远距负融像性聚散、近距正融像性聚散、聚散灵活度、集合近点、调节幅度、调节灵活度、负相对调节比较均无差异(P>0.05)。与框架眼镜相比,配戴MFRGP近距水平隐斜、近距负融像性聚散、调节滞后、正相对调节增大,AC/A降低(P=0.023、0.048、0.001、0.013、0.046); 与SVRGP相比,MFRGP近距水平隐斜、调节滞后、正相对调节增大,AC/A降低(P=0.014、<0.001、0.001、0.009)。

结论：配戴MFRGP会引起近距水平隐斜、调节滞后、正相对调节增大和AC/A降低,这些变化可能对配戴者近距离用眼产生一定影响,在临床应用中要考虑这些预期的变化,以便正确评估和管理患者。     

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。     

汉语发展性阅读障碍儿童调节功能与眼位的研究

目的　探讨汉语发展性阅读障碍儿童与正常儿童调节功能与眼位各参数的变化,明确影响汉语发展性阅读障碍儿童视觉效率的关键视觉因素。方法　病例对照研究。选取天津市12所小学五年级学生1458名。根据识字量和瑞文智力的测验结果,筛选出98名汉语发展性阅读障碍儿童为试验组,随机选取年龄、性别、瑞文智力与之匹配的98名正常儿童为对照组。对两组儿童进行调节近点、调节幅度、调节灵活度以及眼位的检查,并进行统计学分析。结果　两组儿童的双眼调节灵活度、近距离水平眼位差异均有统计学意义（均为P＜0.05）,而单眼或双眼的调节近点及调节幅度、单眼的调节灵活度、近距离垂直眼位、远距离水平眼位及垂直眼位差异均无统计学意义（均为P＞0.05）。结论　汉语发展性阅读性障碍组儿童的双眼调节灵活度下降,双眼近距离水平眼位偏大,提示这些视觉因素可能是引起汉语发展性阅读障碍儿童视觉效率下降的原因。     

Binocular coordination of saccades at far and at near in children and in adults

The goal of the study was to test the quality of binocular coordination of saccades in children and adults, and its dependency upon the viewing distance. Fourteen normal children (4.5-12 years old) and 10 normal adults (22-44 years old) participated. Two distances were studied: far (150 cm) and close (20 cm). Horizontal saccades from both eyes were recorded simultaneously by a photoelectric device. The results show (i) poor binocular coordination of saccades in children is distance dependent: coordination is particularly poor at near and could compromise single binocular vision; and (ii) post-saccadic drift analysis indicates that stability of the eyes after the saccade as well as the quality of binocular alignment during fixation are poor in children, regardless of the viewing distance. The results provide a reference for the normal development of binocular motor control and have important implications for reading in young children.     

Funktionelle Ergebnisse nach Korrektur der Presbyopie mittels bilateraler intrastromaler Femtosekundenlaserbehandlung

Purpose

The purpose of this study was to evaluate the results of bilateral intrastromal femtosecond laser correction of presbyopia (INTRACOR).

Methods

In a prospective study 17 patients were enrolled who had previously received binocular treatment in a two-step approach. Postoperative (4–8 months) outcomes were compared with a matched control group who had undergone only unilateral surgery of the non-dominant eye (n?=?17 patients, 24 months after surgery).

Results

The binocular distance corrected near visual acuity (DCNVA) showed the same median but lower scattering of values after bilateral treatment: 0.10 (median in logMAR) (0.30/??0.10 min/max) (study) versus 0.10 (0.50/??0.10) (control). In the study group, however, a higher loss of binocular corrected distance visual acuity (CDVA) was found: 23.5 %, 70.6 %, 5.9 % (0, ??1, ??2 lines) (study) versus 35.3 %, 64.7 % and 0 %, repectively (control).

Conclusions

Regarding the reduced CDVA INTRACOR should initially only be performed in the non-dominant eye. In selected cases binocular treatment can improve DCNVA; however, careful risk-benefit assessment and informed consent are necessary.     

Prevalence of visual impairment, cataract surgery and awareness of cataract and glaucoma in Bhaktapur district of Nepal: The Bhaktapur Glaucoma Study

Background

The present study investigates two different treatment options for convergence insufficiency CI for a group of children with reading difficulties referred by educational institutes to a specialist eye clinic in Vienna.

Methods

One hundred and thirty four subjects (aged 7-14 years) with reading difficulties were referred from an educational institute in Vienna, Austria for visual assessment. Each child was given either 8Δ base-in reading spectacles (n = 51) or computerised home vision therapy (HTS) (n = 51). Thirty two participants refused all treatment offered (clinical control group). A full visual assessment including reading speed and accuracy were conducted pre- and post-treatment.

Results

Factorial analyses demonstrated statistically significant changes between results obtained for visits 1 and 2 for total reading time, reading error score, amplitude of accommodation and binocular accommodative facility (within subjects effects) (p < 0.05). Significant differences were also demonstrated between treatment groups for total reading time, reading error score and binocular accommodative facility (between subjects effects) (p < 0.05).

Conclusions

Reading difficulties with no apparent intellectual or psychological foundation may be due to a binocular vision anomaly such as convergence insufficiency. Both the HTS and prismatic correction are highly effective treatment options for convergence insufficiency. Prismatic correction can be considered an effective alternative to HTS.     

Axial growth and binocular function following bilateral lensectomy and scleral fixation of an intraocular lens in nontraumatic ectopia lentis

Purpose  

To evaluate binocular function (BF) and changes in axial length (AL) bilaterally in pseudophakic eyes of children after lensectomy and scleral fixation of an intraocular lens (IOL) for nontraumatic ectopia lentis.     

Binocular and Accommodative Characteristics in a Normal Population

Purpose: To study binocular and accommodative characteristics and their associations with age and gender in an Iranian young adult population.

Methods: In this cross-sectional study, multistage cluster sampling was done from the students of Mashhad University of Medical Sciences. All participants had visual acuity, refraction, and cover tests followed by measurements of the near point of convergence (NPC), amplitude of accommodation (AA), monocular and binocular accommodative facility (MAF and BAF) using ±2.00 diopter (D) flipper lenses, and negative and positive relative accommodation (NRA and PRA). Near and distance fusional vergence reserves were measured using prism bar, and near associated phoria was assessed using the Mallett unit.

Results: The mean age of the participants was 22.5±4.4 years (range: 18-35 years). The binocular and accommodative characteristics and their means in the studied sample included: mean distance dissociated phoria: 1.15 exophoria±2.04 prism diopters (PD), near dissociated phoria: 5.02 exophoria±4.74 PD, near associated phoria: 0.55 base-in±1.02, gradient accommodative convergence/accommodation (AC/A) ratio: 4.66±1.59, NPC: 5.27±3.60 cm, MAF: 11.33±5.58 cpm, BAF: 8.84±4.47 cpm, NRA: 2.08±0.33 D, PRA:-2.92±0.76 D, and AA: 11.14±2.6 D. In the multiple regression model including age and gender, near exophoria was significantly higher in men and levels of near base-out-break and near base-out-recovery were higher in females. Distance exophoria, distance base-in-break, distance base-in-recovery, and NPC increased with age and near base-out-break, PRA, BAF, MAF, and AA significantly decreased with age.

Conclusion: Studied indices in this study significantly differ from available guidelines and these differences must be considered when making diagnostic or therapeutic decisions. Certain indices can be affected by age and gender.     

Re-alignment of the eyes, with prisms and with eye surgery, affects postural stability differently in children with strabismus

Aim

The purpose of the study was to examine the effect of eye re-alignment (after wearing prisms and after eye surgery) on postural stability in children with strabismus.

Methods

Nine children with strabismus (6–13?years old) participated in the study. A posturography platform (TechnoConcept) was used to examine posture in quiet stance at two distances: steady fixation of a target at near distance (40?cm) and at far distance (200?cm). Four different conditions were tested: with and without prisms before eye surgery, and twice after eye surgery.

Results

The surface of the CoP increased after wearing prisms (540?mm² compared to the condition without prisms (462?mm²); in contrast, eye surgery reduced the surface of the CoP, leading to improved postural control (454?mm² and 401?mm², respectively, in the post 1 and post 2 surgery condition). Unlike normal children, strabismic children showed no improvement in postural control at near distance.

Conclusions

Binocular visual and motor changes affect body sway; adaptive mechanisms induced by eye re-alignment after surgery allow improved postural control. The absence of dependency on distance in postural stability in strabismic children could be due to their impaired depth perception and to the poor integrity of the visual signal required to control posture.