Tm中0m=。+学号方 ORIGINAL ARTICLE Accommodative Lag Using Dynamic Retinoscopy:Age Norms for School-Age Children JULIE F.MCCLELLAND,PhD,MCOptom and KATHRYN J.SAUNDERS,PhD,MCOptom Virion ScieeRer Group Schos of Biomedical Scieneo.Uwiverrityer Londomery.Norier irand ABSTRACT:Background.Nott dynamic retinoscopy (DR)is a technique that provides an objective,rapid assessment of accommodative function.Presently there are no data available regarding age norms of accommodative function for school-age children using Nott DR.Methods.Accommodative responses were assessed in a group of 125 school-age children (4 to 15 years of age)using Nott DR.A range of accommodative demands was included [4 D (25 cm),6 D(16.7 cm),and 10 D(10 cm)].All the subjects had fully corrected refractive errors and a binocular visual acuity of at least 6/6.Resulls.Accommodative responses were assessed successfully at each distance with all the subjects (N=125).A mean overall lag of accummodation was nuted with each age group at each distance tested.Regression analysis demonstrated no significant difference in accommodative responses hetween age groups (p 0.531 at 4 D,p 0.062 at 6 D,and p =0.883 at 10 D).Therefore,results for all the age categories were grouped together to produce a table of normal ranges of accommodation for children aged 4 to 15 years for the three stimuli demands.The mean lag of accommodation was found to be 0.30 0.39 D at 4 D,0.74 0.58 D at 6 D,and 2.50 1.27 D at 10 D.The normal ranges of accommodation (95%confidence limits)were 2.94 to 4.46 D at 4 D,4.12 to 6.40 D at 6 D,and 5.02 to 10.00 D at 10 D.Concfusfons.A comprehensive table has been produced detailing the mean lags and normal ranges of accommodative responses expected for school-age children when using Nott DR.These data allow practitioners and researchers to determine whether accommodative responses measured using Nott DR are within normal limits.(Optom Vis5c2004:81:929-933) Key Words:accommodative lag,accommodative response,Nott dynamic retinoscopy,age norms,school-age children nasment of acommolariv function shuuld form an pcople with crbeal plsy and Down syndrome.Althaugh important part of the opcometric examination of all chil many researchers have used Nott DR.there is a paucity of data dren.This may he achieved using a number of different describing what coeirutesa norml accommodative response technigucs.Ocular accommodation is moet oommonly asoessed with this techniquc. clinically using the sbjecrive "push-up"test.which meures the Rouse et a performed an extensive study examining accom amplinade afarenmmodation ing thr RAF mk.It is alo impor- modarive rexponses of 721 shoalape children (4 to 12 yran af tant to examine other aspects of a subject's accommodative status. age).They used the monocular estimate method (MEM]of DR to induding his o her accommodative accuracy ot response. determine thelg of accommodatioe at the child's usual wocking Noct dynamic rcinospy(DR)isa tchnique that provicks the disancc.This type af DR invohs wing phcrical knst to as clinicin with a rapid objecrive mesurement of the refractive sta ccommodative respooses.The sudy provides clinicians with use tus of the eyes while the ajeet views a near tangrt.A modificd ful data regarding narmal lgs of accommodation.When esamin- Nott DR technique has previously been shown to provide valid ing young aduks,Del Pilar Cacho et al.report that MEM DR is and repeatable meurements ofaccommodative response in adules not the optimal technique to ases accommodive responses.Del and childnen.It is a technique that may be ased to awcs accom- Pilar Cacha et al mparted that the Nott method (which s modative function in situations in which subjective methods are changes in working distaces rather than introducing lerses)wasa unsuitable and has been used to study accommodative function in more approprate technique to asess ligs of accommodation in e可dta名amVd8,t以，Dorabe,m Copyright American Academy of Optometry.Unauthorized reproduction of this artide is proh bited
ORIGINAL ARTICLE Accommodative Lag Using Dynamic Retinoscopy: Age Norms for School-Age Children JULIE F. MCCLELLAND, PhD, MCOptom and KATHRYN J. SAUNDERS, PhD, MCOptom Vision Science Research Group, School of Biomedical Sciences, University of Ulster, Londonderry, Northern Ireland ABSTRACT: Background. Nott dynamic retinoscopy (DR) is a technique that provides an objective, rapid assessment of accommodative function. Presently there are no data available regarding age norms of accommodative function for school-age children using Nott DR. Methods. Accommodative responses were assessed in a group of 125 school-age children (4 to 15 years of age) using Nott DR. A range of accommodative demands was included [4 D (25 cm), 6 D (16.7 cm), and 10 D (10 cm)]. All the subjects had fully corrected refractive errors and a binocular visual acuity of at least 6/6. Results. Accommodative responses were assessed successfully at each distance with all the subjects (N 125). A mean overall lag of accommodation was noted with each age group at each distance tested. Regression analysis demonstrated no significant difference in accommodative responses between age groups (p 0.531 at 4 D, p 0.062 at 6 D, and p 0.883 at 10 D). Therefore, results for all the age categories were grouped together to produce a table of normal ranges of accommodation for children aged 4 to 15 years for the three stimuli demands. The mean lag of accommodation was found to be 0.30 0.39 D at 4 D, 0.74 0.58 D at 6 D, and 2.50 1.27 D at 10 D. The normal ranges of accommodation (95% confidence limits) were 2.94 to 4.46 D at 4 D, 4.12 to 6.40 D at 6 D, and 5.02 to 10.00 D at 10 D. Conclusions. A comprehensive table has been produced detailing the mean lags and normal ranges of accommodative responses expected for school-age children when using Nott DR. These data allow practitioners and researchers to determine whether accommodative responses measured using Nott DR are within normal limits. (Optom Vis Sci 2004;81:929–933) Key Words: accommodative lag, accommodative response, Nott dynamic retinoscopy, age norms, school-age children An assessment of accommodative function should form an important part of the optometric examination of all children. This may be achieved using a number of different techniques. Ocular accommodation is most commonly assessed clinically using the subjective “push-up” test, which measures the amplitude of accommodation using the RAF rule. It is also important to examine other aspects of a subject’s accommodative status, including his or her accommodative accuracy or response. Nott dynamic retinoscopy (DR) is a technique that provides the clinician with a rapid objective measurement of the refractive status of the eyes while the subject views a near target. A modified Nott DR technique has previously been shown to provide valid and repeatable measurements of accommodative response in adults and children.1 It is a technique that may be used to assess accommodative function in situations in which subjective methods are unsuitable and has been used to study accommodative function in people with cerebral palsy and Down syndrome.2, 3 Although many researchers have used Nott DR, there is a paucity of data describing what constitutes a normal accommodative response with this technique.4–6 Rouse et al.7 performed an extensive study examining accommodative responses of 721 school-age children (4 to 12 years of age). They used the monocular estimate method (MEM) of DR to determine the lag of accommodation at the child’s usual working distance. This type of DR involves using spherical lenses to assess accommodative responses. The study provides clinicians with useful data regarding normal lags of accommodation. When examining young adults, Del Pilar Cacho et al.8 report that MEM DR is not the optimal technique to assess accommodative responses. Del Pilar Cacho et al.8 reported that the Nott method9 (which uses changes in working distances rather than introducing lenses) was a more appropriate technique to assess lags of accommodation in 1040-5488/04/8112-0929/0 VOL. 81, NO. 12, PP. 929–933 OPTOMETRY AND VISION SCIENCE Copyright © 2004 American Academy of Optometry Optometry and Vision Science, Vol. 81, No. 12, December 2004
930 Accummodation Lag in School Children-MCledland Ssunders yuung adulhts because it is the method that kast contaminates the n对s Leat and Gargon eamined the accnmmodative respomse ofa diverse goup af 5s visually and developenentally normal subjecrs aged to 35 years using a modification ofNot DR They peovided griphs detailing the mean accommodarive reponse and 95%con fidence limis for four different age groups.These data allow peac- titioners using Nott DR to deterine whether the accommodative reponse mesued is within normal limits.Ilowever,the graphical presentation of the pormal ranges males applicaion of these re ats to clinical data cumbersome. The preent sudy aims to provide dinicians with comprehen. sive ormive accommodative response daa foc deveopmentally and visaally pormal school-age children (4 to 15 years of age)uasing Nutt DR.The proent sudy aims to enhance Leat and Gargon's udhy pmoncing dafrum a rger subjcct base for clinicians in practice. FIGURE 1. Dynamic itinoscopy. METHODS Ethical approval for this study was obtained from the Northem the fine desail at the center of the target hy heing asked quegions Education and Lbrary Board and the Universiry of Ulster ethcal about the pictures.Thas helped to maineain interes and accom- cummittoes'This research followed the trnetsofthe Doclaration of modarive effort.The retinosoope ws placed longide ands close Hebinki.Twn lecal schools wrm conta ted.nne primary lvel and aspossble to the target.and the retinoscope reflex was observed ane secnndary leve.The study was diseued with the school prin- while the subjeet was fixatingthe target.All the meaourements were cipak.and information letters and consent forms were sent to taken under binoculr viewing conditions from the last byper- parents.Written consent focnis were received from 128 parents. metropic meridian of the subject's eyes.A "with"mowenent indi The subjeets'ages rangnd from 4 to 15 years (mean age,9.27 cated a lag of accommodation,and the practicioner moved farthe 3.55 years;64 male,64 female). away from the subject to reach a neutral point.An "against"move Children wich a binoculr acuiry of dor with asignif. ment indicated a lead of accommodatioe,and the practitioner icant unconected refractive erro(myopia50 DS,hy moved closer to the pacient ochieve neutraliry.The Tanget re permetropia+2.00 DS,or astigmatism >1.00 DC as ascer- mained in its original posicion.The exminer placed afingero the tained by the author J.M using distance sic retimoscopy)were ruler o currespond with the distance of the retinosope.The di- excluded from the study N=3),and a letter was sent to cheir opric distance from thecomeal apex to the dge of the retinosoope parentso gurdidvising the children to endn opomeist was noted when neutrality was achieved (when the "with"or for a full eye examination.All the other chidren with significant against"movement disappeared)and was recorded as the lag foc refractive erors were tesed wich apprupriace pctade orcion lead)of accommodation.Alhough the retinuscope was held s in placc. ck tuthe rule as pussbk,it cd nut be xactly along the linc of Accommodative responses were assessed using a Nott DR tech sight.Benokmnrepoeted that if the retinascope were within 10. nique at three different accommodative demands (4 D,6 D,and this would induce an erme of no more than 0.25 D.Because the 10 D).A distance of 25 cm (4 D)was sdectod because it curre- subjects were enoouraped to view the oenter of the target,this off spondol with the :merag:working dlistanee ofa child (25.4 cm).A asix erme would havr hern 11.3"ar 10 cm,68"at 16.7 cm,and distance of 10 em (10 D)ws chasen hrcause the authors hoped to 4.6"at 25 cm.The gmme aherver (.M.)made all the measurements examine the acoummodative repons while the visual system was under te.The three disances usd in the proint study alo allawfrcbe made withThe RESULTS targets were persemtod first at 25 cm,then moed to 16.7 cm,and Acoomnmeditive respoeses were suceessfully asesed at all the finally co10 cm.The oeder of target preseneation bas been shown diseances fiom all the subjects.Data from 125 subjects were in to hanve no significant impact on the resuls clndod in the analysis.Hetwern 7 and 17 subjocts wize included in The target ed toimulae acoommodition was an interally each age group (Tahle 1)Deseriptive statistical aralysis of the illuminated.translucent,white Perspex cube measuring4x x 4 resules demontrated an overall lg of accommodatice at each dis cm.Igh comtast picrures containing,a ne of sparial frequen- tance in all the age groups.In all the ge groups,the notmal range cies were drawn on each face of the cube (Fig.1). (mean accommodative resporse1.96x SD)widened wich an The DR technique used in the present study was the same as the increase in the accommodative demand.As the subjects'age in modified Nott chnique and has been shown to prowide valid and creased.there wis less varubility in the nomative range.The repeaable mearements of accommodative response..The beoadest normal range and most variabiliry were found ar the 10-D meter rule was held in place to ensure the zero mark was aligned stimulus distance in the iyearold age group (82to 11.26 D). with the corneal apex (Fg 1).The subject was encouraged to view Leads of accomnmodation were not cummonh demonstrated.At Opronerry and Vinien Sciraee.Vol.81.Ne.12.Docember 2004 Copyright American Academy cf Optometry.Unauthorized reproduction of this article is prohbited
young adults because it is the method that least contaminates the results. Leat and Gargon10 examined the accommodative response of a diverse group of 55 visually and developmentally normal subjects aged 3 to 35 years using a modification of Nott DR. They provided graphs detailing the mean accommodative response and 95% confidence limits for four different age groups. These data allow practitioners using Nott DR to determine whether the accommodative response measured is within normal limits. However, the graphical presentation of the normal ranges makes application of these results to clinical data cumbersome. The present study aims to provide clinicians with comprehensive normative accommodative response data for developmentally and visually normal school-age children (4 to 15 years of age) using Nott DR. The present study aims to enhance Leat and Gargon’s study10 by producing easily accessible data from a larger subject base for clinicians in practice. METHODS Ethical approval for this study was obtained from the Northern Education and Library Board and the University of Ulster ethical committees. This research followed the tenets of the Declaration of Helsinki. Two local schools were contacted, one primary level and one secondary level. The study was discussed with the school principals, and information letters and consent forms were sent to parents. Written consent forms were received from 128 parents. The subjects’ ages ranged from 4 to 15 years (mean age, 9.27 3.53 years; 64 male, 64 female). Children with a binocular acuity of 6/6 and/or with a significant uncorrected refractive error11–13 (myopia 0.50 DS, hypermetropia 2.00 DS, or astigmatism 1.00 DC as ascertained by the author J.M. using distance static retinoscopy) were excluded from the study (N 3), and a letter was sent to their parents or guardians advising the children to attend an optometrist for a full eye examination. All the other children with significant refractive errors were tested with appropriate spectacle correction in place. Accommodative responses were assessed using a Nott DR technique at three different accommodative demands (4 D, 6 D, and 10 D). A distance of 25 cm (4 D) was selected because it corresponded with the average working distance of a child (25.4 cm).7 A distance of 10 cm (10 D) was chosen because the authors hoped to examine the accommodative response while the visual system was under stress. The three distances used in the present study also allow for comparisons to be made with previous studies.10, 14 The targets were presented first at 25 cm, then moved to 16.7 cm, and finally to 10 cm. The order of target presentation has been shown to have no significant impact on the results.10 The target used to stimulate accommodation was an internally illuminated, translucent, white Perspex cube measuring 4 4 4 cm. High contrast pictures containing a range of spatial frequencies were drawn on each face of the cube (Fig. 1). The DR technique used in the present study was the same as the modified Nott technique and has been shown to provide valid and repeatable measurements of accommodative response.1, 3, 10 The meter rule was held in place to ensure the zero mark was aligned with the corneal apex (Fig. 1). The subject was encouraged to view the fine detail at the center of the target by being asked questions about the pictures. This helped to maintain interest and accommodative effort. The retinoscope was placed alongside and as close as possible to the target, and the retinoscope reflex was observed while the subject was fixating the target. All the measurements were taken under binocular viewing conditions from the least hypermetropic meridian of the subject’s eyes. A “with” movement indicated a lag of accommodation, and the practitioner moved farther away from the subject to reach a neutral point. An “against” movement indicated a lead of accommodation, and the practitioner moved closer to the patient to achieve neutrality. The target remained in its original position. The examiner placed a finger on the ruler to correspond with the distance of the retinoscope. The dioptric distance from the corneal apex to the edge of the retinoscope was noted when neutrality was achieved (when the “with” or “against” movement disappeared) and was recorded as the lag (or lead) of accommodation. Although the retinoscope was held as close to the rule as possible, it could not be exactly along the line of sight. Brookman4 reported that if the retinoscope were within 10°, this would induce an error of no more than 0.25 D. Because the subjects were encouraged to view the center of the target, this off axis error would have been 11.3° at 10 cm, 6.8° at 16.7 cm, and 4.6° at 25 cm. The same observer (J.M.) made all the measurements. RESULTS Accommodative responses were successfully assessed at all the distances from all the subjects. Data from 125 subjects were included in the analysis. Between 7 and 17 subjects were included in each age group (Table 1). Descriptive statistical analysis of the results demonstrated an overall lag of accommodation at each distance in all the age groups. In all the age groups, the normal range (mean accommodative response 1.96 SD) widened with an increase in the accommodative demand. As the subjects’ age increased, there was less variability in the normative range. The broadest normal range and most variability were found at the 10-D stimulus distance in the 4-year-old age group (3.82 to 11.26 D). Leads of accommodation were not commonly demonstrated. At FIGURE 1. Dynamic retinoscopy. 930 Accommodation Lag in School Children—McClelland & Saunders Optometry and Vision Science, Vol. 81, No. 12, December 2004
Acccmmodation Lag in School Children-McCldlland Saunders 931 TABLE 1. Mean accommodative response and 95%confidence limits (mean 1.96 x SD)of accommorative response for each age group at cach accommodative demand Accommodative Resporrse ID) A四 4 D Demand 6口Demand 10 D Demand (yrs) Men Normal Rang哭 Mean Nomal Range Mean Normal Range 0 D升 0 助 0 D 11 3.70 252-4.88 5.57 4.286.86 7.54 3.82-11.26 3.86 3.37-4.35 532 4.486.14 7.67 5.36-9.98 17 3.7 275-4.71 522 3.86.44 7.85 5.D1-10.69 10 3.77 3.21-4.31 565 4.27-6.53 月.12 6.06-10.18 10 3.73 3.24-4.22 536 3.97-6.75 7.36 4.42-10.30 3.73 308-4.38 506 4.29-581 7.09 439-0.29 o 3.42 287-3.97 482 4.D1-5.62 6.92 5.63-8.21 3.71 3.024.39 33D 4.10-6.50 7.71 6.09-9.33 12 12 3.79 3.074.51 329 4.31-6.25 7.17 4.949.4D 11 3.75 304-4.46 528 4.10-6.46 6.98 5.59-8.37 14 9 3.49 278-4.20 4.82 3.80-5.84 7.25 4.82-9.68 15 3.0 266-4.54 5.19 3.96.39 H.10 5.65-10.55 the grearest accommodative demand (10 D),rwo subjects demon- noml ranges for the three different stimulas distances.The noe- strated a lead of accoenmodation,11 subjects demonstrated leads mal ranges ofaccommodative responses for each target distance are ofaccommoclation at the 6-T)stimulus,ard 16 subjects at the 4-D) shown in Table 2.This table will allow dinicians to categorize stimulus. patients as having cither normal oe roduced accommodative re- Fig 2 illustrates the accommodative noponse at different dis- sponses for these stimulus distances. tancesby different age groups and suggesis little,if any.effect of age within the tesed range.Regression anaysis revealed that the slope of the regresdon line fitted did not difer significantly from DISCUSSION op=0.531at4Dp=062at60,ndp-0,883at10 A one-way analysis of variance was performod an the resules to The present study describes nocmal data for accomnodative lags determine the effect of age on accommoditive response.Analysis of school-age children using modified version of Nort DR with demonstrated thait there was no seatistically significant differene targets at different distances.A table has been produced that pro- in mean accommodrive respones across the age groups for the vides the dinician using Nott DR with a rapid means for deciding 10-D stimuls distance (p-0.549),the 6-D stimulus distn(p whether achild's accommodative response falls ourside the pormal -0.057),and the 4-D stimulus distance (p-0.385).Therefure, range. reuts for all the age categories were grouped together to produce In the peesent study,the mean lag of accommodation wa found 4o0.0±.39Dat4D,0.74±D58D6D,nd2.50± 1.27 D at 10 D.This is in good igreement with other studies examining lag of accommodation Nott?described bow at 33 cm D)the subject would under-accommodate hy about 0.50 D. Rouse et al7 demonserated an owerall lag of accommodation of 033±035Danl035±0.34 D for the right and left eye% respectively.Subjects in Rouse et al's study'were allowed to use their preferred working distance whBe measurements were taken. The mean working distance was 25.4 cm.This compares well with the mean accommodative lag of 0.30=0).39 [in the peesent study at the 25-cm tanmt distance. In the present study,the widest range of accommodarive re- sponses was peesent in the group of 4-year-old children-This could be attrbuted to a coexcentration or attention diffculty in this yongest gromp.Woodhouse t al assessed accommodative re- sponses of 26 children agd 7 to 11 years using a similar DR Age year technique.Woodhouse et al.demonstrated amean lag of accomn- FIGURE 2. modation of 0.20D to an 11-D stimulus demand.This is a nuch Acoommodatve responses a:4 DiA 6 D In.and 10 Dx)for all the lower lag than the present scudy.in which at 10 D a mean Lg of subgects.The solid line indirates the regneginn line. 2.49 was shen.The relrively few subjeets,narower age rangr. Oproourtry and Viniaw Srimaee,Vol $1,Na.12,Deccmiber 206 Copyright American Academy of Optometry.Unauthonzed reproduction of this artcle is prohibited
the greatest accommodative demand (10 D), two subjects demonstrated a lead of accommodation, 11 subjects demonstrated leads of accommodation at the 6-D stimulus, and 16 subjects at the 4-D stimulus. Fig. 2 illustrates the accommodative response at different distances by different age groups and suggests little, if any, effect of age within the tested range. Regression analysis revealed that the slope of the regression line fitted did not differ significantly from zero (p 0.531 at 4 D, p 0.062 at 6 D, and p 0.883 at 10 D). A one-way analysis of variance was performed on the results to determine the effect of age on accommodative response. Analysis demonstrated that there was no statistically significant difference in mean accommodative responses across the age groups for the 10-D stimulus distance (p 0.549), the 6-D stimulus distance (p 0.057), and the 4-D stimulus distance (p 0.385). Therefore, results for all the age categories were grouped together to produce normal ranges for the three different stimulus distances. The normal ranges of accommodative responses for each target distance are shown in Table 2. This table will allow clinicians to categorize patients as having either normal or reduced accommodative responses for these stimulus distances. DISCUSSION The present study describes normal data for accommodative lags of school-age children using a modified version of Nott DR with targets at different distances. A table has been produced that provides the clinician using Nott DR with a rapid means for deciding whether a child’s accommodative response falls outside the normal range. In the present study, the mean lag of accommodation was found to be 0.30 0.39 D at 4 D, 0.74 0.58 D at 6 D, and 2.50 1.27 D at 10 D. This is in good agreement with other studies examining lag of accommodation. Nott9 described how at 33 cm (3 D) the subject would under-accommodate by about 0.50 D. Rouse et al.7 demonstrated an overall lag of accommodation of 0.33 0.35 D and 0.35 0.34 D for the right and left eyes, respectively. Subjects in Rouse et al.’s study7 were allowed to use their preferred working distance while measurements were taken. The mean working distance was 25.4 cm. This compares well with the mean accommodative lag of 0.30 0.39 D in the present study at the 25-cm target distance. In the present study, the widest range of accommodative responses was present in the group of 4-year-old children. This could be attributed to a concentration or attention difficulty in this youngest group. Woodhouse et al.3 assessed accommodative responses of 26 children aged 7 to 11 years using a similar DR technique. Woodhouse et al.3 demonstrated a mean lag of accommodation of 0.20 D to an 11-D stimulus demand. This is a much lower lag than the present study, in which at 10 D a mean lag of 2.49 D was shown. The relatively few subjects, narrower age range, TABLE 1. Mean accommodative response and 95% confidence limits (mean 1.96 SD) of accommodative response for each age group at each accommodative demand Age (yrs) n Accommodative Response (D) 4 D Demand 6 D Demand 10 D Demand Mean (D) Normal Range (D) Mean (D) Normal Range (D) Mean (D) Normal Range (D) 4 11 3.70 2.52–4.88 5.57 4.28–6.86 7.54 3.82–11.26 5 10 3.86 3.37–4.35 5.32 4.48–6.14 7.67 5.36–9.98 6 17 3.73 2.75–4.71 5.22 3.98–6.44 7.85 5.01–10.69 7 10 3.77 3.21–4.31 5.65 4.77–6.53 8.12 6.06–10.18 8 10 3.73 3.24–4.22 5.36 3.97–6.75 7.36 4.42–10.30 9 9 3.73 3.08–4.38 5.06 4.29–5.81 7.09 4.39–9.79 10 7 3.42 2.87–3.97 4.82 4.01–5.62 6.92 5.63–8.21 11 9 3.71 3.02–4.39 5.30 4.10–6.50 7.71 6.09–9.33 12 12 3.79 3.07–4.51 5.29 4.31–6.25 7.17 4.94–9.40 13 11 3.75 3.04–4.46 5.28 4.10–6.46 6.98 5.59–8.37 14 9 3.49 2.78–4.20 4.82 3.80–5.84 7.25 4.82–9.68 15 10 3.60 2.66–4.54 5.19 3.99–6.39 8.10 5.65–10.55 FIGURE 2. Accommodative responses at4D(Œ), 6 D (), and 10 D () for all the subjects. The solid line indicates the regression line. Accommodation Lag in School Children—McClelland & Saunders 931 Optometry and Vision Science, Vol. 81, No. 12, December 2004
932 Accommodation Lag in School Children McClelland Saunders TABLE 2. Mean accommodative response and 95%confidence limits for all age groups A出←15rs 4 D Deinund 6 D Demand 10 D Demand Noemal range (mean respoese 25D) 2.94-4.46 4.12-6.40 502-1D00 D Re比an±5D)D) 3.70±039 5.26±D58 7.51±1.27 Lag (mean±5D引D 0.30±039 0.74±058 2.49±1.27 and higher mean age in Woodhousc ct al.'s sudymay account for and rocarcher to readily identify patients and subjcors whus ac- this difterence. commodative responses fall outside the normal range for their ige The greatest variability in the results was found at the greatest These data allow decisions to be made on whether accommo accommodative demand.This is similar to findings of Leat and dative responses measured using,a modified version of Noct DR Gargon.They reported that las of sccomnodation increased are within pormal limsits for 1-to 15-year-old children.These with an increase in age and an incrcase in accommodative de- data are necesary for future studies on accommodative re- mand.In the present study,the mean lag at 4 D in the 4-year- sponses in neurologically and visually normal children and in old age group was 0.30 D.which increased to 2.46 D at the those with impairments.They will also aid clinicians treating 10-D demand.The lag also increased with age (meat4D these children to identify ccommodative deficits and target increased from 0.30 D in the 4-year-old group to 0.40 D in the treatment appropriately. 15-year-old age group)but not to a statistically significant de- gree.Leat and Gargon sbowed that at the 4-D demand the accommodative lag increased significantly from 0.480.42 D ACKNOWLEDGMENTS in the G.to 10-year-old age group to 0.60 =0.44 D in the 11- to 26-year-old group.This is similar to findings reporred by We nme the acoair tiat partiripated in the gady.Mill Straud Primeary Rouse et al,who demoastrated a statistically significant in- Scoal Parirab and Daminitan C年，.nd re pupibfiv i叹r crease in accommodative lag from 0.28=0.44 D in 4-year-old 点.u mppored女Th:Callege fOpromi.Syrd女af children to 0.45+0.30 D in 12 years old children.The dif MPv时stIa ferences berween the results of the present study and those of Reehed Mareb 10.2004 aceepied Aug 2004. Rouse et al."might be actributed to the different rype of DR (monocular estimate method)used by Rouse et al.and might also be compounded by the variable test distances used in Rouse REFERENCES et al.'s study.It might be that the older children used reduced 1.Leat S].Redaced acoommodarion in chikiren with cerebral palsy working distances compared with younger children:therefore. Ophthalmic Physial Ope 1996:16:385-90. lags appeared greater in older children.The smaller number of 2.MeCldlland JF.Sunden K).The sepeaabiliry and validity of dy- subjeets in Leat and Gargon's studyle and the higher age of the namic recinoscopy in assesing the accommodative respoese.Oph. oldlest suhjeet may esplain the diserepxancy herueen their results thalmic Physiol Opt 2003:25:24-%0. and those of the present study. 3.Wondhouse JM.Meades JS,Lear 5].Saunder K].Reducod accom- Chen and O'Learys examined accommodative responses of mocation in children wich D syndmme,Ineg Ophthalmol Vis 118 children (aged 3 to 14 years)using a Canon Autoref R-1 841995:542382-7 (Tokyo,Japan).Their fisation target,which s used ar si differ- ent gimulus digances (n.1,25.4,and 5 D),was the 6(24 linc of pertormance of young hum an infants.J Am Opcom Assoc 1951:52: 865-9. The Osterberg Picrotial Sight Test Chart for Liule Children.Their 5.Bank MS.Inlant rel results agreed with the present sndy because they found no signif. din19820:20j-32 icant differenee berween accommodative responses across all the age groups.Unfortunarely,they did nat report the mean accom- modative nesponses or normal ranges that might be eapoctod when 0pIun5ex199162:857-66. axessing,accommodarive responses using the Canon R-I 7.Rote MW,Hutet RF,SflL民A nomaLive s山lyuf山00- Autorefractor. modative lag in clementany chool chdcen.Am JOpom Phyiol The aim of the present study was to prowide practitioners with a 0pt198461:69-7. gde to determine whether arcommodtive tesponses asessed 8.del Pilr Cacho M,aia-MmgA,ir由-BerrcibeuJ代，lcaA with a modifiod version of Nott DR are within nommal limits.We Comparison berween MEM and Noct dynamic recinoscopy.Opiom have pruducd a simpk table that practitioners may consul dei Vs5d19976:60-5. 9.Nor I5.Dymamie skiametry,accnmmodition and cnmeprece, ing the mean accommodative response and 9%confidence limits Am J Physinl Ope 1925:6i:490-503. for three different tangrt distanes To identify cases of accommo- I0.LaS,Gargun J1 Accummo山e ropoot in ch山en and young dative dysfimction,it is dsirabk to hae a dear idea of what a aduhsuing dyaOphthalmic Tyolpe6 normal respons shoukl be.Those narmative data allow dinicians 575-84. Opcontry and Velas Srimre,Vol 81,No.12,Deoemiber 224 Copyright American Academy of Optometry.Unauthonzed reproduction of this artcle is prohibited
and higher mean age in Woodhouse et al.’s study3 may account for this difference. The greatest variability in the results was found at the greatest accommodative demand. This is similar to findings of Leat and Gargon.10 They reported that lags of accommodation increased with an increase in age and an increase in accommodative demand. In the present study, the mean lag at 4 D in the 4-yearold age group was 0.30 D, which increased to 2.46 D at the 10-D demand. The lag also increased with age (mean lag at 4 D increased from 0.30 D in the 4-year-old group to 0.40 D in the 15-year-old age group) but not to a statistically significant degree. Leat and Gargon10 showed that at the 4-D demand the accommodative lag increased significantly from 0.48 0.42 D in the 6- to 10-year-old age group to 0.60 0.44 D in the 11- to 26-year-old group. This is similar to findings reported by Rouse et al.,7 who demonstrated a statistically significant increase in accommodative lag from 0.28 0.44 D in 4-year-old children to 0.45 0.30 D in 12-years-old children. The differences between the results of the present study and those of Rouse et al.7 might be attributed to the different type of DR (monocular estimate method) used by Rouse et al. and might also be compounded by the variable test distances used in Rouse et al.’s study. It might be that the older children used reduced working distances compared with younger children; therefore, lags appeared greater in older children. The smaller number of subjects in Leat and Gargon’s study10 and the higher age of the oldest subject may explain the discrepancy between their results and those of the present study. Chen and O’Leary15 examined accommodative responses of 118 children (aged 3 to 14 years) using a Canon Autoref R-1 (Tokyo, Japan). Their fixation target, which was used at six different stimulus distances (0, 1, 2, 3, 4, and 5 D), was the 6/24 line of The Osterberg Pictorial Sight Test Chart for Little Children. Their results agreed with the present study because they found no significant difference between accommodative responses across all the age groups. Unfortunately, they did not report the mean accommodative responses or normal ranges that might be expected when assessing accommodative responses using the Canon R-1 Autorefractor. The aim of the present study was to provide practitioners with a guide to determine whether accommodative responses assessed with a modified version of Nott DR are within normal limits. We have produced a simple table that practitioners may consult detailing the mean accommodative response and 95% confidence limits for three different target distances. To identify cases of accommodative dysfunction, it is desirable to have a clear idea of what a normal response should be. These normative data allow clinicians and researchers to readily identify patients and subjects whose accommodative responses fall outside the normal range for their age. These data allow decisions to be made on whether accommodative responses measured using a modified version of Nott DR are within normal limits for 4- to 15-year-old children. These data are necessary for future studies on accommodative responses in neurologically and visually normal children and in those with impairments. They will also aid clinicians treating these children to identify accommodative deficits and target treatment appropriately. ACKNOWLEDGMENTS We thank the schools that participated in the study, Mill Strand Primary School, Portrush and Dominican College, Portstewart, and the pupils for taking part. J.M. was supported by The College of Optometrists. Supported by a Nuffield equipment grant (SCI/180/96/41/G). Received March 10, 2004; accepted August 30, 2004. REFERENCES 1. Leat SJ. Reduced accommodation in children with cerebral palsy. Ophthalmic Physiol Opt 1996;16:385–90. 2. McClelland JF, Saunders KJ. The repeatability and validity of dynamic retinoscopy in assessing the accommodative response. Ophthalmic Physiol Opt 2003;23:243–50. 3. Woodhouse JM, Meades JS, Leat SJ, Saunders KJ. Reduced accommodation in children with Down syndrome. Invest Ophthalmol Vis Sci 1993;34:2382–7. 4. Brookman KE. A retinoscopic method of assessing accommodative performance of young human infants. J Am Optom Assoc 1981;52: 865–9. 5. Banks MS. Infant refraction and accommodation. Int Ophthalmol Clin 1980;20:205–32. 6. Jackson TW, Goss DA. Variation and correlation of clinical tests of accommodative function in a sample of school-age children. J Am Optom Assoc 1991;62:857–66. 7. Rouse MW, Hutter RF, Shiftlett R. A normative study of the accommodative lag in elementary school children. Am J Optom Physiol Opt 1984;61:693–7. 8. del Pilar Cacho M, Garcia-Munoz A, Garcia-Bernabeu JR, Lopez A. Comparison between MEM and Nott dynamic retinoscopy. Optom Vis Sci 1999;76:650–5. 9. Nott IS. Dynamic skiametry, accommodation and convergence. Am J Physiol Opt 1925;6:490–503. 10. Leat SJ, Gargon JL. Accommodative response in children and young adults using dynamic retinoscopy. Ophthalmic Physiol Opt 1996;16: 375–84. TABLE 2. Mean accommodative response and 95% confidence limits for all age groups Age, 4–15 yrs 4 D Demand 6 D Demand 10 D Demand Normal range (mean response 2SD) (D) 2.94–4.46 4.12–6.40 5.02–10.00 Response (mean SD) (D) 3.70 0.39 5.26 0.58 7.51 1.27 Lag (mean SD) (D) 0.30 0.39 0.74 0.58 2.49 1.27 932 Accommodation Lag in School Children—McClelland & Saunders Optometry and Vision Science, Vol. 81, No. 12, December 2004
Accommodanon Lag in School Children-Mcclland Saunders 433 11.Leat S].Shune RH.Westall CA.Assessing Chiliren's Visioe:A 15.Chen AH,O'Leary D].Are there age differences in the accommoda- Handbouk.《Oxfu止Butterwunth-Hima,193 tive ropume carve betwren 3 and 14 years of ap Ophtldic 12.Ingram RM,Walker(Refrattion aa meansal peedicting wuint ur hnim￥2m02:2119-25. amblyopia in preschool siblegs of children known to have these defecrs.Br I Ophthamol 197963238-2 13,Abrahimoon M,Fahian G,Sjoutrand J Chanprs in astigatio J.F.MeClelland berwren thersof I and 4yar:a longirdinal anidy BrJOphthal- Viriow Scieuce Restaurel Group 以198572：14-9. Schosl of Biomedicil Sciences 14.Woodhouse JM.Cregg M,Gnnter HL Sanders DP,Saunders KJ. Pakeman VH,Parker M.Fraser WI.Sastry P.The effect of age. Unstnary of Liter xixe ul tarpel,and coniive lctors un accummudative rexpoee ul Coleniue Co..Lswdonderry children with Duwn syedrume Invest (Ophshalmol Vis Sci 2000. Northern Irekmd BT52 ISA 4124-s5 -LRMC区ae@Bter ac uk Oydovntry snf Visiay Srimare,Vol 81.No.12.Devemher 2036 Copyright American Academy of Optometry.Unauthonzed reproduction of this artcle is prohibited
11. Leat SJ, Shute RH, Westall CA. Assessing Children’s Vision: A Handbook. Oxford: Butterworth-Heinemann, 1993. 12. Ingram RM, Walker C. Refraction as a means of predicting squint or amblyopia in preschool siblings of children known to have these defects. Br J Ophthalmol 1979;63:238–42. 13. Abrahamsson M, Fabian G, Sjostrand J. Changes in astigmatism between the ages of 1 and 4 years: a longitudinal study. Br J Ophthalmol 1988;72:145–9. 14. Woodhouse JM, Cregg M, Gunter HL, Sanders DP, Saunders KJ, Pakeman VH, Parker M, Fraser WI, Sastry P. The effect of age, size of target, and cognitive factors on accommodative responses of children with Down syndrome. Invest Ophthalmol Vis Sci 2000; 41:2479–85. 15. Chen AH, O’Leary DJ. Are there age differences in the accommodative response curve between 3 and 14 years of age? Ophthalmic Physiol Opt 2002;22:119–25. J. F. McClelland Vision Science Research Group School of Biomedical Sciences University of Ulster Coleraine Co., Londonderry Northern Ireland BT52 1SA e-mail: JF.McClelland@ulster.ac.uk Accommodation Lag in School Children—McClelland & Saunders 933 Optometry and Vision Science, Vol. 81, No. 12, December 2004