Ability of non-ophthalmologist doctors to detect eyes with occludable angles using the flashlight test

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ORIGINAL PAPERAbility of non-ophthalmologist doctors to detect eyeswith occludable angles using the flashlight testCarolina Pelegrini Barbosa Gracitelli Bruno Landgren Flavia Bracale Graciani Aline Katia Siqueira Sousa Augusto Paranhos Jr. Tiago Santos PrataReceived: 29 March 2013 / Accepted: 14 September 2013 / Published online: 1 October 2013 Springer Science+Business Media Dordrecht 2013Abstract The aim of this study is to assess the abilityof non-ophthalmologist doctors to detect eyes withoccludable angles using the flashlight test (FLT). Forthis study, a total of 45 patients were prospectivelyenrolled. After an ophthalmological examination allpatients underwent FLT by two non-ophthalmologistexaminers in a masked and standardized fashion. Twogynecologists were chosen, as they often deal withpatients exposed to drugs that can trigger pupillaryblock. An occludable angle was defined as C2quadrants in which the posterior trabecular meshworkwas not visible by gonioscopy without indentation(performed by an experienced glaucoma specialist).Whenever both eyes were eligible, one was randomlyselected for analysis. Sensitivity and specificity fordetection of occludable angles were generated, and theagreement between examiners was assessed. Thisstudy results showed that the mean age was47.1 16.4 years and most patients were female(67.7 %). There was a good agreement betweenobservers for FLT results (j = 0.77; p = 0.04).Similar values of sensitivity and specificity werefound for both examiners (92 and 67 % vs 97 and67 %, respectively). Based on the findings of thisstudy, it was concluded that FLT showed goodsensitivity for detection of eyes with occludableangles. The fact that it can be easily and reliablyperformed by non-ophthalmologist highlights its useas a screening tool in patients requiring medicationsthat can induce angle closure.Keywords Anterior chamber depth Occludable angle Screening method Anticholinergic drugsIntroductionRecent estimates show that more than 67 millionpeople in the world have glaucoma. Although open-angle glaucoma comprises approximately two-thirdsof these cases, angle-closure glaucoma is responsiblefor half of those who are blind from the disease [1, 2].In addition, in populations such as Chinese, Indian andMongolian, its prevalence is equal or even greater thanthat of open-angle glaucoma [1, 37].Primary angle-closure glaucoma (PACG) resultsfrom a combination of predisposing anterior segmentanatomy and unfavorable physiological behavior [2].Currently, it is defined as an occludable angleC. P. B. Gracitelli (&) B. Landgren A. K. S. Sousa A. Paranhos Jr. T. S. PrataOphthalmology Department, Federal University of SaoPaulo, Rua Botucatu, 821 Vila Clementino,04023-062 Sao Paulo, Brazile-mail: carolepm@gmail.comF. B. GracianiGynecology Department, Federal University of Sao Paulo,Sao Paulo, Brazil123Int Ophthalmol (2014) 34:557561DOI 10.1007/s10792-013-9856-xassociated with trabecular meshwork damage/dys-function (typically raised intraocular pressure [IOP] orpresence of peripheral anterior synechiae) and struc-tural and/or functional evidence of glaucomatous opticneuropathy [8]. Although less common than thechronic form, the subacute and acute forms of angleclosure may be the first manifestation of the disease.Reported anatomical risk factors for PACG includeshort axial length, shallow anterior chamber (AC),thick and relatively anterior-positioned lens, and smallcorneal diameter and steep curvature [912]. Althoughan occludable angle can be promptly identified byindentation gonioscopy, the examination is technicallydifficult for non-glaucoma specialists and is notappropriate for large-scale screening [13, 14].Different types of systemic medications may triggeran acute attack in eyes with predisposing anteriorsegment anatomy [1517]. On daily practice, non-ophthalmologist doctors, such as gynecologists, usuallyprescribe these drugs without a preventive AC angleassessment. This situation highlights the importance ofinvestigating a straightforward screening method to aidclinicians in identifying individuals at risk [18].The flashlight test (FLT) is a simple light-basedmethod which has been previously described for ACdepth evaluation [19]. This technique has been used inpopulation-based studies and was found to be a goodscreening tool [2022]. In this study, we aimed toinvestigate the ability of non-ophthalmologist doctorsto identify eyes at risk (those with occludable anglesbased on gonioscopic examination) using the FLT.Materials and methodsThis cross-sectional study adhered to the tenets of theDeclaration of Helsinki and was approved by theInstitutional Review Board of the Federal Universityof Sao Paulo. In addition, written informed consentwas obtained from all participants.PatientsWe prospectively enrolled patients with glaucoma andglaucoma suspects, attending our outpatient clinic. Allpatients underwent a complete ophthalmologicalexamination. Key exclusion criteria were conditionsprecluding clear visualization of the AC (e.g., ptery-gium, corneal opacity), congenital anterior segmentabnormalities, eyelid alterations, ocular trauma andintraocular surgery (incisional or laser procedures).After inclusion, each patient underwent the FLT,performed by two different gynecologists, in separaterooms. The eye to be examined was randomly chosenon the toss of a coin. The test was performed using aMaglite Cell 2D torch. A flashlight beam was directedparallel to the iris from the temporal side as originallyreported by Vargas et al. [19]. Eyes identified ashaving a narrow AC were those in which a nasal irisshadow, formed between the limbus and the pupillaryedge, was visualized. Conversely, eyes identified ashaving a deep chamber were those in which a nasallight reflex, formed between the limbus and thepupillary edge, was visualized. Immediately after theFLT, patients underwent gonioscopic examination(Sussmann four-mirror lens) by a glaucoma specialist(TSP) in a masked fashion. Gonioscopy was per-formed in a dark room using a Zeiss SL130 slit-lampwith the minimum intensity of illumination compat-ible with good visualization. The slit-beam wasshortened so that it did not fall on the pupil. Angleswere graded as occludable (posterior trabecularmeshwork not visible in C2 quadrants without inden-tation) or nonoccludable.Statistical analysisDescriptive analysis was used to present demographicand clinical data. Agreement between the two non-ophthalmologist examiners (gynecologists) and theglaucoma specialist was determined using theweighted Kappa (j) statistic. A j value of 00.2suggests poor agreement, 0.20.6 fair, 0.60.8 sub-stantial, 0.81.0 represents almost perfect agreement,and[0.75 is usually considered good agreement [23].Values of sensitivity and specificity were also gener-ated, considering the gonioscopic grading of the angleas the gold standard.ResultsA total of 45 patients were included. The mean age ofstudy patients was 47.1 16.4 years (range1985 years) and the majority of patients were female(67.7 %). The percentage of eyes identified as havinga narrow AC by the FLT was 20 % for the firstobserver and 18 % for the second observer (n = 9 and558 Int Ophthalmol (2014) 34:5575611238, respectively). The prevalence of occludable anglesaccording to gonioscopy was 20 % (n = 9).The j value was 0.77 (p = 0.04), showing goodagreement between the two gynecologists. Similarvalues of sensitivity and specificity were found for thetwo examiners (92 and 67 % vs 97 and 67 %,respectively (Table 1). Regarding the cases in whichthere was no agreement between gonioscopy and FLTgrading, three eyes with occludable angles wereclassified as having deep ACs while three eyes withnonoccludable angles were classified as having narrowACs by the first observer. For the second observer, twoeyes with occludable angles were classified as havingdeep ACs while one eye with a nonoccludable anglewas classified as having a narrow AC.Examples of eyes with occludable and nonocclud-able angles, correctly identified by the FLT, are givenin Figs. 1 and 2, respectively.DiscussionPatients are often treated by non-ophthalmologistdoctors with systemic medications that can trigger anacute angle-closure attack in anatomically predis-posed eyes [19, 24]. Although a glaucoma specialistcan identify those at risk before such medications areprescribed, this type of specific evaluation is notalways available, and probably not feasible in dailypractice. Gonioscopy itself requires specific trainingand cannot be performed by a general clinician [19,24]. These facts emphasize the need for a reliable andsensitive screening method. In the present study, wedemonstrated the FLT as a useful tool for identifica-tion of eyes at risk (with occludable angles) by non-ophthalmologist doctors.There is scant information in the literature about theuse of the FLT as a screening method. In most of theavailable studies, although non-trained clinicians werenot evaluated as examiners, good sensitivity valueswere found [19, 21, 25]. In our study, investigating theapplicability of the test when performed by twogynecologists, FLT also had good sensitivity (92 %for the first observer and 97 % for the secondobserver), which is in agreement with previouslypublished data [21, 22]. In contrast with the majorityof publications, one study from the south of Indiareported very low sensitivity (45 %) using the sametechnique [26]. One possible reason for the differencesof reported sensitivity values between studies could bethe variability of anterior segment anatomy in somepopulations that could influence the type of angle-closure mechanism, affecting the efficacy of the FLT[24]. Van Herick et al. [27] pointed out that theflashlight method might be subject to misclassificationin eyes with either plateau iris configuration or withcentral shallowing of the AC but wide drainage angles.Table 1 Sensitivity and specificity values for the flashlighttest (two examiners)Observer 1 (%) Observer 2 (%)Sensitivity 92 97Specificity 67 67Considering the gonioscopic grading of the angle as the goldstandardFig. 1 Eye with a nonoccludable angle correctly identified bythe flashlight testFig. 2 Eye with an occludable angle correctly identified by theflashlight testInt Ophthalmol (2014) 34:557561 559123The main clinical implication of our findings is thatthe FLT could be used by general doctors to identifypatients at risk for angle closure before prescribingsome medications. In any medical field, an idealscreening test should have high sensitivity. Although itwould possibly lead to a significant number of falsepositive test results, the majority of the patients at riskcould be detected and referenced to a more specificophthalmological evaluation [25]. The fact that wefound sensitivity values[90 %, independently of theobserver, confirms the FLT as a relevant screeningtool.In the context of our study, it is important to discussthe most common medications that could trigger anacute glaucoma attack. They include topical mydria-tics, anticholinergic drugs, adrenergic agents, drugsfor upper respiratory infections, antidepressants, anti-convulsants, sulfamate derivative, antihistamines andcabergoline [28]. These drugs when prescribed for apatient with an anatomically predisposed eye mayresult in high intraocular pressure, reduction in visualacuity, glaucomatous optic neuropathy, visual fieldloss and blindness [29, 30].Looking carefully at the characteristics of patientsthat develop an acute glaucoma attack, one should becareful with elderly women when prescribing any ofthe above cited medications. There is a predominanceof female patients with pupillary block, which isprobably caused by a shallower AC observed in theseeyes [3134]. In our sample, the majority of patientswere female (67.7 %). Another risk factor is age. Theprevalence of papillary block and PACG alsoincreases with age. The depth and volume of the ACdiminish, which may result from a thickening andforward displacement of the lens [35]. In this study themean age of patients was 47.1 16.4 years, which isnot considered an elderly population.Some specific characteristics of our study should beconsidered. First, our study is limited by its smallsample size and low prevalence of narrow angles,which probably reflects the prevalence of narrowangles in Brazil. Second, some studies have comparedFLT with Van Herick test as a screening test [26]. Wehave chosen not to make a comparison with VanHericks method because our focus was to investigatenon-ophthalmologist doctors as observers.In summary, the FLT showed good sensitivity todetect eyes with occludable angles. The fact thatit can be easily and reliably performed by non-ophthalmologist doctors highlights its use as ascreening tool in patients requiring medications thatcan induce angle closure.Conflict of interest The authors have no conflict of interestregarding the present study.Funding None.References1. Congdon N, Wang F, Tielsch JM (1992) Issues in the epi-demiology and population-based screening of primaryangle-closure glaucoma. Surv Ophthalmol 36:4114232. 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Can J Ophthalmol 19:300302Int Ophthalmol (2014) 34:557561 561123Ability of non-ophthalmologist doctors to detect eyes with occludable angles using the flashlight testAbstractIntroductionMaterials and methodsPatientsStatistical analysisResultsDiscussionReferences

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