1040-5488/02/7909-0614/0 VOL. 79, NO. 9, PP. 614 620 OPTOMETRY AND VISION SCIENCE Copyright 2002 Americn Acdemy of Optometry ORIGINAL ARTICLE Dignostic Signs of Accommodtive Insufficiency PILAR CACHO, OD, ÁNGEL GARCÍA, OD, FRANCISCO LARA, OD, nd M A MAR SEGUÍ, OD Deprtmento Interuniversitrio de Óptic, Universidd de Alicnte, Spin (PC, AG, MMS), Deprtmento de Oftlmologí, AP y ORL, Universidd de Murci, Spin (FL) ABSTRACT: Purpose. To determine which re the most sensitive tests, together with ccommodtive mplitude, to clssify ccommodtive insufficiency (AI), we nlyzed the reltion between monoculr estimted method (MEM) dynmic retinoscopy, monoculr nd binoculr ccommodtive fcility (MAF, BAF), nd positive reltive ccommodtion (PRA) with or without the presence of reduced mplitude of ccommodtion. Methods. We studied 328 symptomtic ptients who presented consecutively to n optometric clinic. From this smple, we selected the 41 ptients who presented mplitude of ccommodtion t lest 2 D below the minimum ge-pproprite mplitude ccording to Hofstetter s formul: 15 0.25 ge. We lso selected dt from 40 consecutive subjects (control group) with no generl binoculr disorders nd norml ccommodtive mplitudes. We studied the specificity nd sensitivity of the four signs relted with the ccommodtive insufficiency: high MEM dynmic retinoscopy, filing MAF nd BAF with minus lenses of 2 D flipper lenses, nd low PRA. Results. Using the stndrd devition s the cutoff, the specificity vlues were MEM 0.88, MAF 1, BAF 0.93, nd PRA 1. When using the men vlue s the cutoff, the specificity diminished, fundmentlly for MEM. The sensitivity for the 41 ptients using stndrd devition s the cutoff ws MEM 0.44, MAF 0.34, BAF 0.27, nd PRA 0.27, nd when using the men vlue s the cutoff the four, sensitivity vlues incresed. Conclusions. According to the sensitivity results, with both cutoffs used, filing the 2 D MAF test seems to be the sign tht is most ssocited with the ccommodtive insufficiency. (Optom Vis Sci 2002; 79:614 620) Key Words: ccommodtive insufficiency, ccommodtive mplitude, monoculr estimte method dynmic retinoscopy, monoculr nd binoculr ccommodtive fcility, positive reltive ccommodtion According to the literture, ccommodtive insufficiency is n ccommodtive nomly chrcterized fundmentlly s hving n mplitude of ccommodtion consistently below the pproprite ge level. However, severl uthors who hve studied this nomly refer to different dignostic criteri. In Tble 1, severl studies hve used different criteri to mke the dignosis. As cn be observed, there re two mjor criteri for dignosing ccommodtive insufficiency: by mens of single clinicl sign nd by using multiple signs. According to the reports tht refer to this ccommodtive disorder using single clinicl signs, some of them define ccommodtive insufficiency simply s diminished ccommodtive mplitude. This is the cse for Dum, 1 who uses the criterion of hving 2 D below Hosfstetter s 2 minimum ge-mplitude formul, 15 0.25 ge, to estblish ptient with low mplitude of ccommodtion. However, not ll of the studies use Hofstetter s formul. Other uthors, such s Mtsuo nd Ohtsuki, 3 pply the sign of reduced ccommodtive mplitude ccording to Dune s 4 criterion, lthough they do not specify exctly how mny diopters below. Similrly, Russell nd Wick 5 define ccommodtive insufficiency s when ptients exhibit n ccommodtive mplitude t lest 2.5 D below tht expected for their respective ge, bsed on Dune s ge norms. 4 Other uthors, however, define ccommodtive insufficiency considering Hofstetter s formul, but binoculrly. For exmple, Dwyer nd Wick 6 define ccommodtive insufficiency s when the binoculr ccommodtive mplitude is 2 D or more below the expected vlue. A number of uthors hve used n dditionl clinicl sign, dded to the essentil one of hving diminished ccommodtive mplitude. Among them re the studies of Hokod 7 nd Rouse et l. 8 In Hokod s 7 report, ccommodtive insufficiency is dignosed when the ptient hs push-up monoculr ccommodtive mplitude t lest 2 D below Hofstetter s clcultion for minimum ge-pproprite mplitude nd positive reltive ccommodtion (PRA) 1.25 D. However, Rouse et l. 8 clssified ptients with ccommodtive insufficiency (ssocited with convergence insufficiency) when the subject filed Hofstetter s minimum mplitude formul or hd greter thn 1 D lg on monoculr estimte method dynmic retinoscopy. The other group of studies of ccommodtive insufficiency re-
Accommodtive Insufficiency Ccho et l. 615 TABLE 1. Summry of severl studies reporting different criteri for dignosing ccommodtive insufficiency (AI). Authors Criteri Used For Dignosing AI Dum 1 AA 2 D below Hofstetter 2 minimum mplitude formul: 15 0.25 ge Mtsuo nd Ohtsuki 3 Reduced AA bsed on Dune s criterion 4 Russell nd Wick 5 AA t lest 2.5 D below the expected for ge bsed on Dune s criterion Dwyer nd Wick 6 Binoculr AA 2Dormore below the expected for the ptient s ge using Hofstetter s formul Hokod 7 AA t lest 2 D below Hofstetter s minimum mplitude formul Decresed PRA, 1.25 D Rouse et l 8 AA fils Hofstetter s minimum mplitude formul, or MEM retinoscopy 1.00 D Scheimn et l 9 AA 2 D from men for ge using Hofstetter s formul At lest 2 signs of 4 dditionl signs b Porcr nd Mrtínez-Plomer 10 AA t lest 2 D below Hofstetter s minimum mplitude formul PRA decresed, 1.25 D Filing ccommodtive fcility with 2.00 D, monoculr 6 cpm, binoculr 3 cpm High MEM, 0.75 D High fused cross-cylinder, 1.00 D Lr et l 11 AA t lest 2 D below Hofstetter s minimum mplitude formul Fil monoculr ccommodtive fcility with 2.00 D, 6 cpm 2 Signs of 3 dditionl signs c AA, ccommodtive mplitude; PRA, positive reltive ccommodtion; MEM, monoculr estimted method. b Scheimn et l 9 : See text for description of these four dditionl signs. c Lr et l 11 : See text for description of these three dditionl signs. fers to multiple clinicl signs for dignosing this ccommodtive nomly. Scheimn et l. 9 specified tht it ws necessry to hve n ccommodtive mplitude 2 D or less thn the minimum estblished by Hofstetter s formul nd to exhibit two of the following four dditionl signs: low positive reltive ccommodtion ( 1.25 D), filing monoculr ccommodtive fcility with minus lenses of 2 D flipper lenses, filing binoculr ccommodtive fcility with minus lenses of 2 D lenses, nd vlue of monoculr estimted method (MEM) dynmic retinoscopy 1 D. Similrly, Porcr nd Mrtínez-Plomer 10 used severl signs, lthough they did not specify how mny signs were necessry to mke n ccurte dignosis. They focused the dignosis on the signs of reduced mplitude of ccommodtion (2 D less thn minimum), vlue of positive reltive ccommodtion 1.25 D, difficulty clering with negtive lenses in both monoculr nd binoculr ccommodtive fcility with 2 D flipper lenses, high MEM finding ( 0.75 D), nd vlue of fused cross-cylinder 1 D. Recently, Lr et l. 11 studied the prevlence of generl binoculr dysfunctions in clinic popultion nd reported the number of signs used for dignosing the ccommodtive insufficiency. They estblished the necessity of two signs to be present: reduced mplitude of ccommodtion (t lest 2 D below minimum Hofstetter s clcultion for ge) nd filing monoculr ccommodtive fcility with 2 D lenses ( 6 cpm). Furthermore, two dditionl signs of the following three needed to be present: filing binoculr ccommodtive fcility with 2 D lenses ( 3 cpm), MEM finding greter thn 0.75 D, nd positive reltive ccommodtion 1.25 D. As cn be observed, there is lck of greement concerning the number of clinicl signs tht combined with diminished ccommodtive mplitude must be used for clssifying ccommodtive insufficiency nd wht their importnce must be to give n ccurte dignosis. For tht reson, we ttempted to determine the most sensitive tests (together with ccommodtive mplitude) for clssifying ccommodtive insufficiency. For this purpose, we nlyzed the reltionship between MEM dynmic retinoscopy, monoculr nd binoculr ccommodtive fcility, nd positive reltive ccommodtion with or without the presence of reduced mplitude of ccommodtion. METHODS From the symptomtic ptients presented consecutively to n optometric clinic, we chose 328 subjects ged 13 to 35 yers. All subjects gve their informed consent fter hving the nture of the tests to be performed explined to them, nd they uthorized the uthors to pply the results obtined in this reserch. All subjects hd norml oculr nd systemic helth nd hd t lest 20/20 visul cuity with their best correction. None of the subjects wore contct lenses, nd subjects with strbismus were excluded. We completed visul exmintion including the following tests: Ptient s history, reflecting the full rnge of symptoms presented by the ptient. The most common resons of presenting complint were symptoms ssocited with reding or other close work, difficulty with ner tsks, inbility to concentrte nd loss of comprehension over time, oculr ftigue, sthenopi, hedches, blurred vision, eyestrin, diplopi, nd sensitivity to light. Oculr helth by mens of ophthlmoscopy nd biomicroscopy. Assessment of refrctive error. Sttic retinoscopy ws performed while the ptient fixted distnt chrt t 6 m. A subjective exmintion ws performed by mens of monoculr fogging method with cross-cylinder, followed by binoculr blncing to stndrd endpoint of mximum plus for best visul cuity (BVA).
616 Accommodtive Insufficiency Ccho et l. Accommodtive nd binoculr vision testing. With the results of the subjective refrctive exmintion in plce (BVA correction), we conducted n evlution of ccommodtive nd binoculr vision including different tests 12 : Assessment of direction nd mgnitude of the horizontl nd verticl phori ws performed with the cover test nd prism br t 6 m nd 40 cm. AC/A rtio ws mesured by mens of grdient nd clculted methods. MEM dynmic retinoscopy 13 ws performed t 40 cm with the result of the subjective exmintion plced in tril frme nd using tril lenses. Positive nd negtive reltive ccommodtions (PRA, NRA) were ssessed while the ptient ws fixting the horizontl line of 20/20 letters t 40 cm. 12 Monoculr nd binoculr ccommodtive fcility (MAF, BAF) ws conducted following the procedure of Zellers et l. 14 We tested both ccommodtive fcility t distnce of 40 cm using 2 D flip lenses nd trget with suppression control. Monoculr ccommodtive mplitude (AA) ws mesured with the push-up method. We lso mesured the positive nd negtive fusionl vergences t distnce nd ner (6 m nd 40 cm, respectively) nd the nerpoint of convergence. Finlly, we exmined stereopsis with Wirt circles (Titmus stereopsis test) nd fixtion disprity with Wesson crd. To void the exminer bis for prticulr results of the tests, one uthor performed the visul exmintions, nd nother uthor nlyzed the ptient dt. Bsed on the optometric literture 1, 3, 5 11 tht ccommodtive mplitude is the essentil sign for dignosing ccommodtive insufficiency, we selected ptients who presented n mplitude of ccommodtion t lest 2 D below minimum ge-pproprite mplitude ccording to Hofstetter s formul 2 :15 0.25 ge. From this nlysis, we obtined 41 ptients who exhibited tht condition. In ddition, we consecutively selected dt from 40 subjects (control group) who did not hve ny ccommodtive nd/or binoculr disorders nd whose ccommodtive mplitudes were norml. Becuse ccommodtive insufficiency is not only relted to low ccommodtive mplitude but lso to signs such s high MEM dynmic retinoscopy, filing monoculr nd binoculr ccommodtive fcility, nd low positive reltive ccommodtion, 8 11 we used these four signs to determine their specificity nd sensitivity t detecting ccommodtive insufficiency in our smple of subjects with diminished ccommodtive mplitude. For this nlysis, it is necessry to define the pss criterion level for ech of these tests, so we considered the men nd stndrd devition vlues published by Scheimn nd Wick 12 to determine the cutoff of ech sign (Tble 2). According to the norml vlues proposed by these uthors, two different types of criteri for estblishing the cutoff cn be defined. The first is using the limit determined by the stndrd devition. As n exmple, the limit of MEM is 0.75 D, so we cn consider result of 1.00 D or higher s filing the test nd vlue of 0.75 D or lower s pssing the test. A similr ssessment cn be used for the other signs (Tble 2). The second criterion uses the men vlue s the cutoff, so the suspect vlues defined by the stndrd devition imply filing the test. In the previous exmple, MEM vlues of 0.50 D or lower would be considered s pssing the test, nd results of 0.75 D or higher would be tken s filing the test. Compring the results of ech criterion, it cn be estblished which cutoff offers the best sensitivity nd specificity vlues. Thus, with the results of the four tests studied for both groups of ptients estblished in our study (41 subjects with diminished ccommodtive mplitude nd 40 subjects with norml mplitude), we determined the sensitivity nd specificity for ech one of the signs, using the right eye results when the monoculr tests were studied. Specificity cn be understood s the proportion of norml cses (in this pper, the subjects with norml ccommodtive mplitude) tht re correctly identified by pssing the test, which is clculted by dividing the number of true negtives (TN) by the sum of true negtives nd flse positives (FP): TN/(TN FP). Sensitivity is the proportion of subjects with diminished ccommodtive mplitude who re correctly identified by filing the test. Sensitivity is clculted by dividing the number of true positives (TP) by the sum of the true positives nd flse negtives (FN): TP/(TP FN). In our cse, positives re considered to be the group of 41 subjects with diminished ccommodtive mplitude. True positives re the number of subjects who did not pss the test nd were in the group of low ccommodtive mplitude. Flse positives re the number of ptient who did not pss the test but who were in the norml group. Negtives re the group of 40 subjects who hve norml ccommodtive mplitude nd hve no ccommodtive or binoculr dysfunction (control group). True negtives re ptients who pssed the test nd were in norml group, nd flse negtives re subjects who pssed the test but were in the group with diminished ccommodtive mplitude. RESULTS Using the cutoff estblished by the stndrd devition for ech test studied, the specificity ws very high for ll tests nlyzed (Tble 3). These vlues indicte tht there is high probbility tht TABLE 2. Cut-off used to clculte specificity nd sensitivity. Signs Men Vlue SD Filing the Test with SD Filing the Test with Men Vlue MEM 0.50 0.25D 1.00 D 0.75 D MAF 11 5 cpm 6 cpm (with 2.00 D) 10 cpm (with 2.00 D) BAF 8 5 cpm 3 cpm (with 2.00 D) 7 cpm (with 2.00 D) PRA 2.37 1.00D 1.25 D 2.25 D MEM, monoculr estimted method dynmic retinoscopy; MAF, monoculr ccommodtive fcility; BAF, binoculr ccommodtive fcility; PRA, positive reltive ccommodtion.
Accommodtive Insufficiency Ccho et l. 617 subject who psses ech test could be considered s ptient with norml ccommodtive mplitude. If the cutoff defined by the men vlue of ech test is used (Tble 2), the specificity does not suffer, except for MEM dynmic retinoscopy, which diminishes to vlue of 0.48. This suggests tht for obtining n dequte vlue of specificity, the stndrd devition vlue should be used s the cutoff for MEM retinoscopy. To determine the sensitivity, the 41 ptients with diminished mplitude of ccommodtion must be studied. Dt for these subjects re represented in Tble 4, where it hs been specified when ech ptient pssed or filed the test s well s whether the result ws within suspect vlues defined by the stndrd devition. Furthermore, to identify ptients who could hve vergence problem, we hve indicted those who hd significnt heterophori t ner ( 2 of esophori or 6 of exophori). 12 When the stndrd devition vlue ws used s cutoff, the sensitivity of the four tests used for dignosing ccommodtive insufficiency ws not very high (Tble 5). Therefore, it cnnot be ssured tht ptient who fils these tests will hve diminished mplitude of ccommodtion. Although these sensitivity vlues re not prticulrly encourging, it is interesting to compre the results of ech test. As cn be observed, the higher sensitivity vlues were ssocited with high MEM dynmic retinoscopy vlues nd filing the monoculr ccommodtive fcility with negtive lenses. The binoculr ccommodtive fcility nd positive reltive ccommodtion showed lower vlues of sensitivity. If the men vlue ws used s cutoff, the sensitivity incresed due to greter number of true positives. As cn be observed in Tble 5, this ws the cse for ll tests, resulting in gretest sensitivity for MEM retinoscopy nd for positive reltive ccommodtion, wheres monoculr nd binoculr ccommodtive fcility showed similr vlues. However, the increse in sensitivity ws not the sme for ll signs: PRA incresed from 0.27 to 0.49, wheres the MAF hrdly modified its sensitivity (from 14 to 16 true positives). These results suggest tht chnging the cutoff modifies the sensitivity, except in the cse of monoculr ccommodtive fcility. As we hve shown, the sensitivity vlues were never high, so it cn be deduced tht most of the 41 ptients with diminished ccommodtive mplitude were not relted to ccommodtive insufficiency becuse they did not present nomlous vlues in tests tht would be ffected by this ccommodtive nomly. To seprte the ptients who simply hd n ccommodtive disorder from the originl 41 subjects, we eliminted subjects who presented significnt heterophori t ner distnce ( 2 esophori nd 6 exophori). Thus, the smple of ptients ws reduced to 26 ptients for whom we clculted the sensitivity for the two estblished cutoffs. Tble 6 shows the sensitivity vlues for these 26 ptients. Using the stndrd devition criterion, the highest sensitivity ws for MAF, followed by MEM nd PRA, lthough gin high vlues re not reched. When the men vlue ws used s the cutoff, the sensitivity incresed, with MAF, MEM, nd PRA reching 0.58. Agin, PRA ws the sign tht hd the highest increse of sensitivity, wheres MAF chnged little. Similr to the originl nlysis, most of the ptients without significnt heterophoris t ner could not be considered to hve ccommodtive insufficiency becuse in no cses were the sensitivity vlues high. DISCUSSION According to our results, the four signs studied for dignosing ccommodtive insufficiency hve high specificity for both cutoff criteri, with the exception of MEM dynmic retinoscopy when the men vlue is used s the cutoff. These results indicte tht very high percentge of ptients who rech the men vlues of PRA, MAF, nd BAF will not hve diminished ccommodtive mplitude. In the cse of MEM dynmic retinoscopy, it is necessry to use the stndrd devition s the cutoff to mintin high level of specificity. However, these specificity vlues re of mrginl clinicl interest: norml vlues of ech test re not ssocited with n nomly of the ccommodtive system. The sensitivity nlysis offers more interesting results. The sensitivity vlues were never high, so there ws no sign strongly ssocited with the presence of diminished mplitude of ccommodtion. However, most clinicins rely on ccommodtive mplitude s gold stndrd for dignosing the ccommodtive insufficiency. Our results suggest the lck of this gold stndrd, indicting difficulty for dignosing this ccommodtive nomly s other signs hve been tken into ccount. Nonetheless, reduction in the ccommodtive mplitude cnnot be used s the only sign for dignosing ccommodtive insufficiency if one ssumes tht in this ccommodtive nomly other signs must be ffected. When nlyzing the sensitivity of the four signs studied, the vlues of BAF were the lowest for both cutoffs used nd for both smples studied. This cn be explined by the fct tht binoculr ccommodtive fcility is binoculr test, nd filing it does not imply necessrily the presence of monoculr problem. 15 Concerning the PRA, its sensitivity vlues were very vrible depending on the cutoff considered. When the stndrd devition vlue ws used, the sensitivity offered low vlues in both smples but incresed considerbly when the men vlue ws used s the cutoff. In fct, the PRA ws the sign with the gretest increse of true positives when the cutoff ws chnged. This finding suggests TABLE 3. Specificity for the smple of 40 ptients with norml ccommodtive mplitude. Test Filure MEM MAF BAF PRA Stndrd devition 0.88 1 0.93 1 35/(35 5) 40/(40 0) 37/(37 3) 40/(40 0) Men vlue 0.48 1 0.90 0.93 19/(19 21) 40/(40 0) 36/(36 4) 37/(37 3) MEM, monoculr estimted method dynmic retinoscopy; MAF, monoculr ccommodtive fcility; BAF, binoculr ccommodtive fcility; PRA, positive reltive ccommodtion.
618 Accommodtive Insufficiency Ccho et l. TABLE 4. Dt for the 41 subjects with diminished mplitude of ccommodtion. Subject MEM PRA MAF BAF Phori 1 E b Exo 2 F F F 3 4 E 5 F E F Eso 6 F F F F 7 Exo 8 F F F F 9 F Eso 10 E Exo 11 F F F E 12 Exo 13 F F F E 14 15 E 16 17 F E Eso 18 19 F E Eso 20 E E 21 F F 22 23 F E F F 24 F F F 25 F F F F 26 E 27 E E Exo 28 E Eso 29 30 F F F E 31 Eso 32 F Eso 33 E 34 F F Eso 35 F F F 36 F E F F 37 E 38 F F Eso 39 F F F 40 Eso 41 F F F MEM, monoculr estimted method dynmic retinoscopy; PRA, positive reltive ccommodtion; MAF, monoculr ccommodtive fcility; BAF, binoculr ccommodtive fcility; Exo, exophori; Eso, esophori. b (F) represents filing the test, nd (E) represents suspect vlues. tht some ptients cn hve suspect vlue of PRA tht is relted to ccommodtive insufficiency. Nonetheless, using only this sign for the dignosis of ccommodtive insufficiency would not be dequte. MEM dynmic retinoscopy lwys presents one of the highest vlues of sensitivity compred with the other signs. However, the number of true positives in ech of the two smples were very different: 18 nd 12 with the stndrd devition s the cutoff nd 23 nd 15 using the men vlue for 41 nd 26 ptients, respectively. This vribility is explined due to the fct tht hving high MEM finding is not only relted to ccommodtive insufficiency but to convergence excess, 9 11 so this sign could not be considered lone for dignosing ccommodtive insufficiency. The monoculr ccommodtive fcility reches reltively high sensitivity vlues compred with the other signs. Only in the smple of 41 ptients using the men vlue s the cutoff cn the sensitivity be considered low. Contrry to wht hppened with MEM dynmic retinoscopy, the number of ptients who filed the MAF ws very similr for the four situtions studied: for ech of the two cutoff used nd for both smples of ptients considered (41 nd 26 subjects). There were 14 ptients who filed the test of MAF nd only two subjects who presented suspect vlues (Tble 4). Of these two ptients, one of them hd high heterophori t ner. This suggests tht filing MAF is not relted to significnt heterophori t ner. In fct, filing monoculr ccommodtive
TABLE 5. Sensitivity results for the smple of 41 ptients using different filure criteri for ech sign. Test Filure MEM MAF BAF PRA Stndrd devition 0.44 0.34 0.27 0.27 18/(18 23) 14/(14 27) 11/(11 30) 11/(11 30) Men vlue 0.56 0.39 0.37 0.49 23/(23 18) 16/(16 25) 15/(15 26) 20/(20 21) MEM, monoculr estimted method dynmic retinoscopy; MAF, monoculr ccommodtive fcility; BAF, binoculr ccommodtive fcility; PRA, positive reltive ccommodtion. TABLE 6. Sensitivity results for the smple of 26 ptients using different filure criteri for ech sign. Accommodtive Insufficiency Ccho et l. 619 Test Filure MEM MAF BAF PRA Stndrd devition 0.46 0.54 0.31 0.38 12/(12 14) 14/(14 12) 8/(8 18) 10/(10 16) Men vlue 0.58 0.58 0.42 0.58 15/(15 11) 15/(15 11) 11/(11 15) 15/(15 11) MEM, monoculr estimted method dynmic retinoscopy; MAF, monoculr ccommodtive fcility; BAF, binoculr ccommodtive fcility; PRA, positive reltive ccommodtion. fcility with 2 D lenses is only ssocited with the presence of the ccommodtive insufficiency nd not with ny other ccommodtive or binoculr disorders. 9 11 All of these results suggest tht of the four signs studied, the MAF is the sign tht is most closely relted to ccommodtive insufficiency. For tht reson we propose to use diminished ccommodtive mplitude together with filing with minus lenses in the monoculr ccommodtive fcility to dignose ccommodtive insufficiency. To evlute this proposl, we compred the dignosis of ccommodtive insufficiency using this criterion with the criteri used by Hokod, 7 Scheimn et l., 9 nd Lr et l. 11 ; these re the only reports in which it is clerly estblished how they dignose this ccommodtive nomly using severl signs. Using the criteri of Hokod 7 (AA diminished plus PRA 1.25 D), 11 of our ptients would hve ccommodtive insufficiency. According to the criteri proposed by Scheimn et l. 9 (AA diminished plus two of four dditionl signs), 17 of our ptients would hve ccommodtive insufficiency. Using the criteri of Lr et l. 11 (AA diminished plus MAF 6 cpm with 2 D lenses plus two of three dditionl signs), 13 of our ptients who would hve ccommodtive insufficiency. With our proposed criterion (AA diminished plus MAF 6 cpm with 2 D lenses), 14 ptients would hve ccommodtive insufficiency. As cn be observed, our results show tht for ccommodtive insufficiency, the number of ptients dignosed with this nomly depends on the sign used nd not necessrily on the number of signs used for its dignosis. However, these results do not gree with wht occurs in some generl binoculr disorders in which it is shown tht when using more signs for dignosing the nomly, the number of dignosed ptients decreses. 16 Finlly, if ptients with significnt heterophori t ner re not considered (Tble 4), the number of subjects dignosed with ccommodtive insufficiency would be 10 using the criteri of Hokod, 7 13 using the criteri of Lr et l., 11 14 using the criteri suggested here, nd lso the sme 14 ptients following the criteri of Scheimn et l. 9 All these results suggest tht the presence of the ccommodtive insufficiency is relted to severl signs tht re ffected t the sme time becuse the number of ptients dignosed hrdly vried when electing two, three, or four different signs. Tht is, when ccommodtive insufficiency relly exists, the mjority of the four signs relted to this nomly will be ffected, so it would not be necessry to use ll of them in the dignosis. For tht reson, we consider tht using only the sign of filing monoculr ccommodtive fcility with minus lenses together with diminished ccommodtive mplitude, we would be ble to dignose ptients with ccommodtive insufficiency. In ny cse, it is cler tht the signs must be compred with the symptoms of the ptient so good dignosis cn tke into ccount both symptoms nd the results of the ccommodtive tests. In our cse, the 14 ptients dignosed with ccommodtive insufficiency presented symptoms ssocited with this nomly, minly difficulty nd discomfort ssocited with ner tsks. CONCLUSIONS The specificity obtined is high for ll the tests nlyzed, so ptient who reches norml vlues for MEM dynmic retinoscopy, monoculr nd binoculr ccommodtive fcility, nd positive reltive ccommodtion will not be relted to ccommodtive insufficiency. Of the four signs studied, none of them reched high vlues of sensitivity, so they cnnot be directly ssocited with diminished mplitude of ccommodtion. If ccommodtive insufficiency is considered s disorder in which severl signs re ffected, it is not pproprite to use the ccommodtive mplitude s the only sign for dignosing it. According to the sensitivity results, with the two cutoff vlues
620 Accommodtive Insufficiency Ccho et l. estblished in our study nd for both smples considered, filing monoculr ccommodtive fcility with 2 D lenses seems to be the sign most ssocited with ccommodtive insufficiency. Thus, we propose using MAF together with diminished ccommodtive mplitude for dignosing this ccommodtive nomly. Using this suggested criterion, the number of ptients dignosed with ccommodtive insufficiency in our smple of ptients is similr to the number of subjects obtined with the criteri proposed by other uthors. ACKNOWLEDGMENTS Portions of this mnuscript were previously presented t the Sixth Interntionl Meeting of the Americn Acdemy of Optometry (Mdrid, Spin, April 7 9, 2000). Received November 20, 2001; revision received Mrch, 22, 2002. REFERENCES 1. Dum KM. Accommodtive dysfunction. Doc Ophthlmol 1983; 55:177 98. 2. Hofstetter HW. Useful ge-mplitude formul. Optom World 1950; 38:42 5. 3. Mtsuo T, Ohtsuki H. Follow-up results of combintion of ccommodtion nd convergence insufficiency in school-ge children nd dolescents. Grefes Arch Clin Exp Ophthlmol 1992;230:166 70. 4. Dune KM. Studies in monoculr nd binoculr ccommodtion with their clinicl ppliction. Am J Ophthlmol 1922;5:565 77. 5. Russell GE, Wick B. A prospective study of tretment of ccommodtive insufficiency. Optom Vis Sci 1993;70:131 5. 6. Dwyer P, Wick B. The influence of refrctive correction upon disorders of vergence nd ccommodtion. Optom Vis Sci 1995;72: 224 32. 7. Hokod SC. Generl binoculr dysfunctions in n urbn optometry clinic. J Am Optom Assoc 1985;56:560 2. 8. Rouse MW, Borsting E, Hymn L, Hussein M, Cotter SA, Flynn M, Scheimn M, Gllwy M, De Lnd PN, The Convergence Insufficiency nd Reding Study (CIRS) Group. Frequency of convergence insufficiency mong fifth nd sixth grders. Optom Vis Sci 1999;76: 643 9. 9. Scheimn M, Gllwy M, Coulter R, Reinstein F, Ciner E, Herzberg C, Prisi M. Prevlence of vision nd oculr disese conditions in clinicl peditric popultion. J Am Optom Assoc 1996;67:193 202. 10. Porcr E, Mrtinez-Plomer A. Prevlence of generl binoculr dysfunctions in popultion of university students. Optom Vis Sci 1997; 74:111 3. 11. Lr F, Ccho P, Grcí A, Megís R. Generl binoculr disorders: prevlence in clinic popultion. Ophthlmic Physiol Opt 2001;21: 70 4. 12. Scheimn M, Wick B. Clinicl Mngement of Binoculr Vision: Heterophoric, Accommodtive nd Eye Movement Disorders. Phildelphi: JB Lippincott, 1994:3 31. 13. Rouse MW, London R, Allen DC. An evlution of the monoculr estimte method of dynmic retinoscopy. Am J Optom Physiol Opt 1982;59:234 9. 14. Zellers JA, Alpert TL, Rouse MW. A review of the literture nd normtive study of ccommodtive fcility. J Am Optom Assoc 1984; 55:31 7. 15. Grcí A, Ccho P, Lr F, Megís R. The reltion between ccommodtive fcility nd generl binoculr dysfunction. Ophthlmic Physiol Opt 2000;20:98 104. 16. Rouse MW, Hymn L, Hussein M, Soln H. Frequency of convergence insufficiency in optometry clinic settings. Convergence Insufficiency nd Reding Study (CIRS) Group. Optom Vis Sci 1998;75: 88 96. Pilr Ccho Mrtínez Deprtmento Interuniversitrio de Óptic Aprtdo 99.Universidd de Alicnte 03080 Alicnte, Spin e-mil: ccho@u.es