allergic 
 conjunctivitis constitutes a group of diseases affecting the ocular surface ; 
 however , different kinds of conjunctival disorders are grouped under this 
 umbrella term for this single clinical entity . seasonal and perennial allergic 
 conjunctivitis ( sac and pac ) can be defined as recurrent and bilateral 
 conjunctival inflammation with exacerbations in different seasons of the year 
 caused by direct exposure of the ocular surface to airborne allergens . both are 
 mainly dependent on classical type i hypersensitivity in which patients have 
 positive skin prick tests and specific ige in serum to airborne allergens . ocular findings 
 are scant or even absent and are not related to symptom intensity . vernal 
 keratoconjunctivitis , a chronic severe inflammatory disease of the conjunctiva 
 usually recurring bilaterally and seasonally ( spring and summer ) , occurs predominantly 
 in male children and young adults with a personal or family history of atopy . itching is the most significant symptom in these patients , although cobblestone 
 papillae , excess mucus , and intense photophobia may be observed . corneal 
 involvement may occur and result in permanent vision damage . the pathogenesis 
 is more complex than that of sac and pac , and a leading role of an inflammatory 
 network not confined to the classical ige - mast cell immediate hypersensitivity 
 paradigm , but characterised mainly by th2-type inflammation with mast cells , basophils , 
 eosinophils , and polyclonal ige activation , has been suggested . spt and serum specific ige antibody test are often not positive , 
 although total serum ige levels are high . eosinophils are present in both tears 
 and conjunctival scrapings . a 
 new lacrimal test based on total ige determination has been commercialised to 
 diagnose allergic conjunctivitis . total tear ige has been considered to play an 
 important role in allergic conjunctivitis and it has been shown that the 
 measurement of tear ige concentrations can aid the diagnosis of this condition [ 35 ] . lacrytest ( adiatec s.a , nantes , 
  france ) is a 
 rapid immunoassay for total ige determination in tears . this assay indicates , 
 in a qualitative manner , the presence of total class e immunoglobulin in tears 
 with levels above the normal value ( < 2  ku / l , 3  ng / ml ) . in order 
 to investigate whether lacrytest could be a screening tool to diagnose 
 allergic conjunctivitis , we analysed the results of the test in patients with 
 allergic conjunctivitis and compared them with a control group in a cross - sectional 
 study . patients 
 were systematically enrolled from october 2004 to april 2005 . the study 
 included two centres : institute universitari dexeus of barcelona 
  ( allergy department ) and mutua of 
 terrassa ( ophthalmology department ) . patients were preselected according to a 
 clear history of allergic conjunctivitis . a clinical history was taken and an 
 ophthalmic examination and finally a skin prick test ( spt ) to airborne 
 allergens and a conjunctival allergen provocation test ( cpt ) were performed if 
 the spt was positive . the vernal 
 keratoconjunctivitis ( vkc ) group was based on clinical history and ophthalmic 
 examination ( giant papillae or superficial keratitis ) . seasonal and perennial allergic conjunctivitis 
 ( ige - mediated allergic conjunctivitis ) were diagnosed by clinical history , 
 positive spt to pneumoallergens and a positive conjunctival - specific 
 challenge test . ophthalmic examination was not a basis to diagnose 
 them because they are acute 
 forms of conjunctivitis and some patients could not have ocular symptoms and 
 signs of active allergic conjunctivitis at the moment of the visit . the control group comprised patients 
 with no symptoms of allergy ( atopic dermatitis , rhinitis , or asthma ) or 
 conjunctivitis in their clinical history , and with normal ophthalmic 
 examination and negative spt . after 
 the division into three groups and with or without signs of active allergic 
 conjunctivitis in that moment , lacrytest was performed in one eye for the 
 control and vernal keratoconjunctivitis groups and in both eyes for the ige - mediated 
 allergic conjunctivitis group : in one eye immediately after the conjunctival - specific 
 challenge test and in the other in which the allergen was not instilled to 
 compare the results between eyes . all 
 patients underwent spt performed according to standard procedure   with dermatophagoides pteronyssinus , dermatophagoides farinae , dermatophagoides microceras , cat and dog 
 epithelium , moulds ( aspergillus 
 fumigatus , alternaria alternata ) , pollens ( phleum pratense , cynodon 
 dactilon , phragmites comunis , olea europaea , platanus acerifolia , cupressus 
 arizonica , pinus radiata , parietaria judaica , artemisia vulgaris , chenopodium album , plantago lanceolata ) , latex , and cockroach ( blatella germanica ) . this test was performed with the 
 allergen suspected of being one of the aetiologic causes of ige - mediated 
 conjunctivitis in each patient , chosen on the basis of clinical history 
 correlation and spt results . each patient 
 was skin prick tested on the volar surface of the forearm with four ten - fold serial dilutions of the 
 specific allergen extract ; the cpt was 
 started with the dilution before the one that was positive in the spt ( mean 
 wheal diameter 3  mm ) and one drop was instilled into the conjunctival sac . the 
 dilutions instilled were increased every twenty minutes until the test proved 
 positive . criteria for a positive test were congestion of the conjunctival 
 mucosa , itching , and eye watering . a strip is placed in the 
 lower conjunctival fornix and , when wet with tears , is removed . total ige reacts 
 with a gold - labelled antibody and is immobilised with the uptake of anti - ige 
 antibody . signal intensity is dependent on the total ige level . for normal 
 value , below 2.5 the positive results could be 
 divided among the three groups on a semiqualitative scale : for low total ige 
 levels , 2.5 to 10  ku / l , intensity of the signal in the ige reactive field was lower 
 than that of the control line ; for medium total ige levels , 10 to 40  ku / l , 
 intensity was closer to that of the control line ; and for high total ige levels 
 > 40  ku / l , intensity was stronger than the control . the 
 following statistical tests were used for the inferential analysis : fisher 's 
 exact test for qualitative variables , mann - whitney u or kruskall - wallis tests 
 ( for 2 or 3 groups , resp . ) for semiquantitative ordinal measurements , 
 and the macnemar test for binary paired data . sensitivity , specificity , and 
 positive predictive value were calculated with standard formulae . , chicago il ) , and the cia software for 
 calculation of the 95% confidence intervals . the level of 
 significance was established at p = .05 ( two - sided ) . mean ( standard deviation ) age 
 was 30.6 ( 20.2 ) years ( range : 576 ) . the main demographic characteristics and 
 different clinical conjunctivitis groups are summarised in table 1 . the 
 lacrytest was positive in only 6 patients with ige - mediated conjunctivitis 
 ( 20% ) and 8 patients with vernal keratoconjunctivitis ( 88.9% ) and was negative in 
 all controls ( 100% ) . differences were significant when the three groups were 
 compared ( p = .003 ) ; pair - wise comparisons of vkc versus the other groups were 
 statistically significant ( p < .001 for both comparisons ) , but not between 
 ige - mediated conjunctivitis and control groups ( p = .157 ) . ( figure 1 ) . if 
 the result of the ocular test in its positive semiqualitative scale ( negative , 
 low , medium , and high ) is analysed , the results among the three groups were also 
 significant ( p < .001 ) ; pair - wise comparisons of control versus vkc and vkc versus 
 ige - mediated conjunctivitis were statistically significant ( p < .001 for both 
 comparisons ) , but not between control versus ige - mediated conjunctivitis groups 
 ( p = .066 ) ( figure 2 ) . results 
 of the lacrimal test used in ige - mediated conjunctivitis improved after the 
 conjunctival provocation test had been applied to the contralateral eye in each 
 subject . all 6 previously positive results remained positive , but 14 new 
 positives were observed among the 24 previously negative ( 58.3% , mcnemar test 
 p < .001 ) ( figure 3 ) . regarding 
 the lacrytest results ( table 2 ) , in the ige - mediated conjunctivitis group 
 sensitivity was 20% , specificity 100% , positive predictive value 100% , and negative predictive value 38.46% , while in 
 vkc sensitivity was 88.88% , specificity 100% , positive predictive value 100% , 
 and negative predictive value 93.75% ( table 3 ) . if results after the cpt were 
 analysed in the ige - mediated conjunctivitis group ( table 2 ) , sensitivity was 
 66.66% , specificity 100% , positive predictive value 100% , and negative predictive 
 value 60% . the 
 eye is one of the major targets of allergic disorders , either alone or 
 accompanied by other allergic affection . the ocular component may be the most 
 prominent and sometimes disabling feature of the allergy . the acute forms ( seasonal 
 and perennial allergic conjunctivitis ) are commonly seen in an allergy department , 
 and over 50% of patients also have a history of rhinitis , whereas the more 
 chronic forms   ( vernal keratoconjunctivitis , atopic 
 keratoconjunctivitis , and giant papillary conjunctivitis ) can be seen more often 
 in an ophthalmology department since patients report only ocular symptoms . the acute 
 forms are mediated by a type i hypersensitivity response and the chronic forms 
 have a more complex immunological basis and a chronic inflammatory component . based 
 on the finding of high total ige levels in allergic conjunctivitis tears , nantes , france ) , 
 which qualitatively indicates the presence of total class e immunoglobulins in 
 tears with levels above normal values . positive levels of the test indicate an 
 allergic conjunctivitis and negative levels rule out this aetiology . we 
 decided to evaluate the lacrimal test because it was rapid and easy to perform 
 and a prospective study was designed to ascertain its reliability . our clinical 
 data showed the lacrytest to be positive in only 6 of 30 patients ( 20% ) with 
 ige - mediated conjunctival allergy , confirmed by spt and cpt . this is a very low 
 value compared with other studies in which the ige - mediated conjunctivitis 
 group showed the most pronounced local ige production [ 12 , 13 ] ; however 
 the test showed an increased positive value after conjunctival specific 
 provocation ( 20 of 30 patients ; 66.7% ) . tear ige levels are known to have a 
 significant influence on intensity of the inflammatory process and the 
 correlation between cpt and lacrimal ige has been demonstrated . 
 during allergic reactions , the local synthesis of ige is elevated and total 
 tear ige increases because of the 
 lacrimal ige that have filtered through the blood - tear barrier ; 
 thus , it is logical that the results proved more positive after exposure to the 
 allergen . in any event , these findings merit further studies to confirm and 
 explain this result . in 
 the vernal keratoconjunctivitis group , locally - produced ige levels have been shown to be the largest contributor to 
 the severity of allergic conjunctivitis , particularly in chronic 
 forms , and local ige production in vkc is increased compared with controls [ 13 , 14 ] although no clinical differences were observed in atopic 
 keratoconjunctivitis ( akc ) . the 
 lacrytest has very high specificity and positive predictive value ( 100% ) ; thus , 
 a positive test could point to an allergic aetiology , but the low number of positive 
 cases found in the group of ige - mediated allergy ( sensitivity 20% , negative 
 predictive value 38.46% ) indicates that this test can not be the only parameter to 
 achieve an aetiological diagnosis , as occurs with serum ige . this test is not 
 useful for allergists because we have other more sensitive and specific methods 
 to diagnose ige - mediated allergic conjunctivitis ; however , it could be helpful 
 to ophthalmologists to confirm an ige - mediated reaction or vkc if the result is 
 positive . negative results should be sent to the allergist for the allergic aetiology 
 to be definitively confirmed or ruled out .
total tear ige has been considered to play an important role in allergic conjunctivitis , and measurement has been considered useful for diagnosis . 
 the aim of this study was to ascertain whether lacrytest , a new commercialised method to detect ige levels in lacrimal fluid , could constitute a screening test for the diagnosis of allergic conjunctivitis . 
 this was a cross - sectional study . 
 patients with seasonal and perennial allergic conjunctivitis , vernal keratoconjunctivitis and a control group were included . 
 clinical history , ophthalmic examination , skin prick test and conjunctival provocation test were obtained . 
 lacrytest was later performed in all groups . 
 fifty - four patients were enrolled : thirty with ige - mediated conjunctivitis and , nine with vernal keratoconjunctivitis and fifteen controls . 
 lacrytest was negative in all controls , positive in 20% of the ige - mediated conjunctivitis group and in 88.9% of the vernal keratoconjunctivitis group . 
 global statistically - significant differences were found among the three groups ( p = .003 ) . 
 sensitivity of the test in the ige - mediated conjunctivitis group was 20% , specificity 100% , positive predictive value 100% , and negative predictive value 38.46% , while in vkc sensitivity was 88.88% , specificity 100% , positive predictive value 100% , and negative predictive value 93.75% . 
 our data confirm that this test is not useful for screening allergic conjunctivitis . 
 lacrytest , while not providing any useful information to an allergist , could be helpful for ophthalmologists to confirm an ige - mediated or vkc conjunctivitis .