Ocular morbidity on headache ruled out of systemic causes—A prevalence study carried out at a community based hospital in Nepal

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www.journalofoptometry.org

ORIGINAL

ARTICLE

Ocular

morbidity

on

headache

ruled

out

of

systemic

causes----A

prevalence

study

carried

out

at

a

community

based

hospital

in

Nepal

Sanjay

Marasini

a_,_∗

_,

_Jyoti

_Khadka

b

_,

_Purnima

_Raj

_Karnikar

_Sthapit

a

_,

Ranjana

Sharma

a

_,

_Bhagvat

_Prasad

_Nepal

a

a_Department_of_{Ophthalmology,}_Dhulikhel_Hospital,_Kathmandu_University_Hospital,_Dhulikhel,_Nepal b_School_of_Optometry_and_Vision_Science,_Flinders_University,_Bedford_Park,_Australia

Received27November2011;accepted20January2012 Availableonline31March2012

KEYWORDS Binocularvision anomalies; Convergence insufﬁciency; Headache; Refractiveerrors Abstract

Purpose:Theassociationbetweenophthalmicanomaliesandheadachestillneedstobe inves-tigatedlargely.WeaimedtolookforitinthecontextofaruralcommunityhospitalofNepal.

Methods:Hundredpatientswithheadachewereinvestigatedfor ophthalmicanomaliesafter theprobablesystemicassociationwasruledout.Allthepatientswereﬁrstexaminedby gen-eralphysician,otorhinolaryngologistandpsychiatrist.Ocularevaluationconsistedofdetailed refractive,binocularityassessmentandanteriorandposteriorsegmentexamination.Datawere analyzedusingt-test,chi-squaretest,multiplelogisticregression, oddsratioaswellas fre-quencyandpercentages.

Results: Femaleabovetheageof17sufferedmore(p<0.05).Frontalheadachewasmore com-monthanoccipital(p>0.05).Instudentsandhousewivesfrontalheadachewasmorecommon (OR3.467,0.848---14.174;95%CIand1.167,0.303---4.499;95%CI).Refractiveerrorwas associ-atedwithfrontalheadache(OR,1.429,1.130---0.806,95%CI).Onpresentation,88%hadvisual acuity6/9orbetter.Forty-fourpercenthadrefractiveerroramongwhomastigmatismwasmore frequent (63.63%)followedby hyperopia(27.27%)andmyopia(9.09%).Known eyeproblems weresignificantlyassociatedwithrefractiveerrorandbinocularvisionanomalies(p<0.001). Convergenceinsufficiency(16.25%)andfusionalvergence(11.25%)deficiencieswerecommon amongunstablebinocularity.

Conclusion:Ocular anomalies co-exist withheadache complainsvery frequently. Refractive andbinocularvisionanomaliesneedtobelargelyinvestigatedinallheadachepatients.Itis importanttogetagoodheadachehistorysothatpatientscanbereferredtotheappropriate specialist.

∗_{Corresponding}_author.

E-mailaddress:thesanzay@gmail.com(S.Marasini).

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PALABRASCLAVE Anomalíasdevisión binocular; Insuﬁcienciade convergencia; Cefalea; Erroresderefracción

Morbilidadocularsobrecefaleadescartadaentrelascausassistémicas:estudiode prevalenciallevadoacaboenunhospitaldeunacomunidadenNepal

Resumen

Objetivo: Laasociaciónentreanomalíasoftálmicasycefaleatodavíadebeinvestigarseafondo. NuestroobjetivofueexaminarloenelcontextodeunhospitaldeunacomunidadruraldeNepal.

Métodos: Se examinaron cien pacientescon cefalea enbusca de anomalías oftálmicas una vez descartada unaposible asociaciónsistémica.Todoslospacientesfueron exploradospor unmédicogeneral,unotorrinolaringólogoyunpsiquiatra.Laevaluaciónocularconsistióenun examendetalladorefractivodelabinocularidadyunexamendelsegmentoanterioryposterior. Losdatosseanalizaronutilizandolapruebadelat,lapruebadela␹2_al_cuadrado,_regresión logísticamúltiple,razóndeprobabilidades,asícomofrecuenciayporcentajes.

Resultados: Lasmujeresmayoresde17 añossufrieronmás(p<0,05).Lacefaleafrontalfue másfrecuentequelaoccipital(p>0,05).Enestudiantesyamasdecasafuemásfrecuentela cefaleafrontal(OR3,467,0,848 -14,174;ICdel95%y1,167,0,303-4,499;ICdel95%).El errorderefracciónseasoció concefaleafrontal(OR,1,429,1,130-0,806,ICdel95%).Enla presentación,el88%teníanunaagudezavisualde6/9omejor.Un40%presentaronerroresde refracción,entreloscualeselmásfrecuentefueastigmatismo(63,63%),hipermetropía(27,27%) ymiopía(9,09%).Losproblemasocularesconocidosseasociarondemanerasignificativacon errorderefracciónyanomalíasdevisiónbinocular(p<0,001).Lainsuficienciadeconvergencia (16,25%)ylosdéficitsdevergenciafusional(11,25%)fueronfrecuentesenlavisiónbinocular inestable.

Conclusión: Lasanomalíasocularescoexistenmuyfrecuentementeconcasosdecefalea.Las anomalíasderefracciónydevisiónbinoculardebeninvestigarseafondoentodoslospacientes concefalea.Esimportanteobtenerbuenosantecedentesdecefaleaparapoderremitiralos pacientesalespecialistaadecuado.

Introduction

Headachehasbeendeﬁnedasthepainlocatedabove orbit-omeatal line.1 _It_is _one _of_the _frequent _reasons_to_seek _a

consultationwithhealthcarepractitioners.2_It_is_a_difﬁcult

conditiontoestablishtheactualcause.Diagnosisand treat-mentisoftenanimpossibletaskwithoutthecorrectviews ofetiology.3

Primary headache (headache without underlying disor-ders)prevalencevarieswithage,9---11%inschoolchildren.4

Thepreponderanceofheadacheishigherinfemale.Inmore than 80% patients, headache starts beforeage 40 with a lowerprevalencerateatanadvancedage(>50years).5

Sim-ilarly, highly conﬂicting prevalence has been observed in differentcountriesas21.2% inthe US,6 _96%_in _Denmark,7

andpast-yearprevalencerangesfrom13.4%intheUS,6_to

87.3%inCanada.8

The evidence in the literature for a strong associa-tionbetweenoculo-visualproblemsandheadacheisweak.2

Still patients who believe that appropriate ocular exam-ination and treatment help to lessen their headache visitoptometrists’andophthalmologists’veryfrequently.8,9

Headache being one of the most common neurological symptomshas often been associated withParkinson’s dis-ease, multiple sclerosis andmyasthenia gravis. Nishimoto etal.revealed thatinheadacheassociatedwith myasthe-niagravis,mildocularsymptomsareassociatedwhichrange from slight degree of diplopia or ptosis which ﬂuctuates dynamicallyandmightleadtotheworseningofheadache.10

Harle and Evans report that in migraine headache often binocular vision anomalies in the formof decompensated heterophoria and reduced stereopsis might be present in subtleform.2

Ophthalmological studies on headache have reported theroleof differentocular diseases like acuteglaucoma, uveitis,opticneuritis11_and_visual_anomalies_like_refractive

errorsandaccommodativeandvergencedeﬁciencies.12_The

uncorrectedrefractiveerrorsareoftenbelievedtobe asso-ciatedwithfrontaland/oroccipitalheadache.13_Eye_strain

asa directcauseofheadachehas longbeen debated.14,15

Very frequently a careful eye examination and a possi-blecorrectionof thedefect hasbeen observed toreduce headachesymptoms.1_Thomas_et_al._noted_that_21%_of

peo-plewithheadacheconsultaneyecarepractitionerwhichis almostsimilartothose(27%)whoseekaconsultationwith ageneralmedicalpractitioner.9_Whittington_reported_that

amongmore than1400 consecutivepatients attendingfor refraction,45%complainedofheadache.16

PatientswhofailSheard’scriterion(Prism Fusional Ver-gence less than twice the near phoria) are expected to sufferfromheadachesymptoms.17 _In_1966,_Gordon_et_al.18

claimedthatminorrefractiveerror(RE)oftencausedmore headacheandsymptomsofeyestrainthanmajorRE.Ciliary musclestrainhasalsobeensuggestedaspossiblesourceof headache.19_To_the_authors’_knowledge,_there_has_not_been

anyreportsonexploringtheophthalmicshareofheadache symptomsamongtheNepalesepeoplewhopresenttoa gen-eralhospital.

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The aim of this study was to investigate whether reported headache complaints of patients attending the general ophthalmic clinic are associated with ophthalmic anomalies.

Methods

Patients

This studyhas a descriptivecross-sectionaldesign. It was conductedin the OphthalmologyDepartmentof Dhulikhel HospitaloveraperiodofthreemonthsfromMarch2010.The hospitalcovers the ruralpopulation of approximately1.9 million people from Kavrepalanchowk, Sindhu-palchowk, Dolakha, Sindhuli, Ramechhap, Bhaktapur and other sur-rounding districts. Hospital targets mainly the people with low socio-economic status who do not have access to the well facilitated health care services. It has pro-videdservices to 50 out of 75 districts of the country so far.20

Weincludedonlythepatientswithheadachewhowere referredfromthemedical,otorhinolaringology(ENT)or psy-chiatry Out Patient Department (OPD). The diagnosis of primary headache was based on International Classiﬁca-tionofHeadacheDisorders:2ndedition(ICHD-II),basedon physicalandneurologicalexaminationsandheadCTand/or MRI.Criteria for eye consultationwere set asfollows:all thepatients needed toundergo thoroughsystemic evalu-ationwith appropriatetests carried out.The appropriate investigationwasordered by the respectivedepartments. Thepatientswithoutdeﬁnite diagnosiswerethenreferred for eye examination. Only the patients withheadache of more than three months duration were included in the study.

Each alternate patient complaining of headache (irre-spectiveofnature/location/intensity)wasincluded inthe study with unrestricted random sampling method regard-less of age, sex and referral. Alternate patients were chosen because it gave a plenty of time for the exami-nation to be carried out in each patient in detail. Blood pressurewasmeasuredineachpatienttolookfor undiag-nosedhypertension.Noneofthepatientshadundiagnosed hypertension.Patients withother diagnosed systemic dis-eases such as migraine, sinusitis, and dental caries or womenwithmenstrualmigraineand/orwomentakingoral contraceptive pills were excluded from the study. Age groupsofthepatientswerecategorizedasschoolchildren (<17 years), non-presbyopic adults (<40 years) and pres-byopic adults(>40 years).This researchwasapproved by the institutional research committee of Dhulikhel Hospi-tal.The tenetsof theHelsinkideclarationwerefollowed. Fullinformedconsentwasobtainedandparticipantswere able to abstain or withdraw from the research at any time without having to give a reason. No participants withdrew after they had arrived at the clinic. It was ensured that the clinician was masked about the iden-tity of the patients with headache participating in the study and those excluded from the study,so that all the tests would be performed with equal emphasis to every patient.

Assessments

Headachequestionnaires

The ﬁrstpart of the evaluation consisted of a structured interviewconductedbyoneofthemedicalinternsand uti-lizing a headachequestionnaire. The questionnaireswere basedonanarticle‘‘Howtotakeahistoryofheadorfacial pain’’byBlau.21_The_{questionnaires}_surveyed_demographic

data (e.g. sex, age, and occupation), headache occur-rence and characteristics, headache onset and timetable (categorizedintomorning,afternoon, evening,during the night,ornone)andpaintopography(categorizedintoback, front, leftsided, right sided or diffuse). The presence or absenceofaccompanyingsymptoms(nausea,vomiting, pho-tophobia, phonophobia) and visual aura were assayed, as were treatment patterns (non-pharmacological measures or medications or spectacles), the presence or absence ofaggravatingfactors(includingphysicalor visualeffort), family history, history of trauma, dentalcaries, sinusitis, menstrual disturbancesandoral contraceptivepillsintake infemales.

Patients were asked to estimate the average number of hoursspentdailyin visuallystrainingtasks (e.g., read-ing,watchingtelevision,andworkingwithacomputer)and whetherheadachesaccompaniedthosetasks.

Visualacuityassessment

Presenting visual acuity was measured for each eye and for both eyes together at distance (6m) with internally illuminated Snellen’s Chart. Near vision was recorded at a distance of 33cm with good illumination with reduced Snellen’sChart.

Refractiveassessment

Retinoscopy was done with a retinoscope at the working distance of 50cm estimating refractive status of patients objectively, which was followed by subjective refraction in which the patient’s response to the corrective lenses wasassessed.Patientswithdissimilarobjectiveand subjec-tive findings,fluctuatingrefractivestatus,below 15years ofage,andpatientswithbinocularvisionanomalies (BVA) underwentcycloplegic retinoscopy(1%cyclopentolate). In these patientssubjective refraction was done afterthree days,whenthecycloplegiaeffectdissapearedcompletely. Spherical andastigmatic deviationsweremeasured tothe nearest 0.50 D. Astigmatic axes were measured to the nearestfivedegrees,negativecylindersbeingusedfor all measurements.Thedegreeofametropiawasstatedas fol-lows: patients with Spherical Equivalent Refractive Error (SERE) of −0.25 and +0.25 Dioptres (D) were considered asemmetropic,SERE>+0.50Dwasconsideredashyperopia andSERE>−0.50Dwasconsideredasmyopia.Astigmatism wasdefinedasthecylindricalcomponentoftherefractive errormorethan0.50D.Allexaminationswerecarriedout bythesingleobserver(optometrist),whodidnotknowthe resultsoftheheadachequestionnaire.

BinocularVisionAssessment(BVA)

Covertestwasperformedatadistanceof6mand40cmwith anopaqueoccluder.Asmallnon-accommodativetargetwas usedtocontrolaccommodation.The typeanddirectionof

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heterophoriaorheterotropiawererecorded.Ocularmotor functions were evaluatedin six cardinal gazes. The Near Pointof Convergence (NPC,which is thenearest distance fromtheeyestowhicheyescanconvergewithout experi-encingdiplopiaorsubjectivediscomfort)wasassessedwith aRoyalAirForce(RAF)rule(aninstrumentusedtomeasure NPCandaccommodativeamplitude).Amplitudeof Accom-modation(AA,itisthedifferenceinthefocuspowerofthe eyewhile fixatingfromneartofar)wasmeasuredineach eyeseparatelyandbinocularlylaterwithpushupmethod. Thefirstsustainedblurwasthennoted(thecarrierof the RAF rule which contains N series letter target is moved toward the patient resting the rule pad on cheeks. The patientisaskedtostatewhenlettersbecomeblurred;the firstsustainedblurisnotedasthedioptricdistancefromthe eye.).

BinocularVisionAssessment(BVA)exceptcovertestwas not carried out onpresbyopes because they areassumed todemonstratevergencedysfunctionduetolossof accom-modative convergence. Fusional reserves were measured witha verticalbarprism usingan accommodative target. Distancedivergent(base-in)followedbyconvergent (base-out)reserveswererecordedasthreevalues,theblurpoint, thebreakpoint,andtherecoverypoint.Nearbase-in and base-outfusionalreserveswererecordedinthesameway. Heterophoria wasmeasured ﬁrst, followed by divergence amplitudesandthenconvergenceamplitudes sothateach testdidnothaveeffectonother.

Otherexaminations

Slit lamp bimicroscopy and detailed fundus examination werecarried outtoruleout ocular pathology.Intraocular pressurewasmeasuredwithGoldmanntonometeronallthe patients.Patientswhosediagnosisremainedinconclusiveon eyeexaminationwerereferredtootherdepartmentssuch asmedical, ENTor psychiatry asrequired andelicitedby headachehistoryforfurtherinvestigation.1

Dataanalysis

Fordata analysiswe included only theright eye in every patientwhenthereweretworeadingsfortwoeyesbecause ﬁndings inboth the eyesof sameindividual aregenerally likelytobesimilar.22_Statistical_analysis_was_done_by

calcu-latingt-testtocomparethemeansoftwogroups,chi-square test for non parametric data, multiple logistic regression toexplorerelationshipbetweenheadacheandoccupation, oddsratiotoexplorerisk ofheadachesitewithrefractive andbinocularitystatusaswellasfrequencyandpercentage to estimate the prevalence. Statistical software ‘Statisti-calPackageforSocial Sciences,version-11.5’wasusedto analyzedata.Statisticalsigniﬁcancewassetatp<0.05.

Results

Studypopulation

A total of 100 patients with headachecomplaints partic-ipated in the study. Non-participation was due to severe

Table 1 Reported headache with age,sex and previous examination(N=100).

Agegroup(years) Sex(no.) Previousexamination(%) Male Female Yes No

<17 11 9 14 6

<40 18 42 33 22

>40 8 12 12 13

Total 37 63 59 41

headachewhilepresenting totheOPD.Fewpatientswere excludedbecauseofthesystemicdiseasesunder investiga-tionand which required simultaneous ocular consultation (likeHypertension,raisedintracranialpressure,pregnancy induced migraine, suspected sinusitis, menstrual distur-bances).Femalegenderpredominatedinthestudy(63%).

Agedistributionandpreviouseyeexamination

Mostof the headache complaintswere in non presbyopic adultswithfemales’outnumberingmalesineachage cate-gory,exceptforschoolchildren(Table1).Fifty-ninepercent ofthepatientshadpreviouseyeexaminationamongwhich 41%hadocularmorbidities.Twenty-fourpatients(24%)had previouseyeexaminationwithinsixmonths.Thefemale pre-ponderanceis not signiﬁcant for the age below 17 years (2

2=5.538, p=0.063) but it is highly signiﬁcant for age above17years(p=0.026).

Proﬁleofheadache

In 35% people headache lasted for one year. Some com-plainedoflong standingheadache ofmore thanone year evenlastinguptonineyears(onepatient).Thepatternof headachesitewiththeoccupationispresentedinTable2.

In multiple logistic regressions, we observed that the frontalandoccipitalheadacheisrelativelydeterminantfor bothstudentsandhousewives(Table3).Itisseenthatthe unstructuredoddsratiowassigniﬁcantwiththeoccupations andsiteofheadachebutthepvalueismorethan0.05.

Previouseyeexaminationwasobservedtobeariskfactor bothforrefractiveerror;OR1.213(0.924---1.593,95%CI)and binocularvisionanomalies;OR3.97(0.111---1.417in95%CI). SixandsevenpatientseachwithREcomplainedoftemporal anddiffuseheadacherespectively.InfourpatientswithBVA diffuseheadachewaspresent.UncorrectedREwasobserved to be a risk factor for frontal headache (Table 4). None

Table 2 Percentagesof reportedsiteof headache com-plainswithoccupation(N=100).

Occupation Frontal Occipital Temporal Diffuse Total

Students 26 6 3 5 40

Housewife 14 9 5 8 36

Others 9 5 4 6 24

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Table3 Relationbetweenoccupationandsiteofheadache(formostfrequentlyobservedvalues).

Occupation Siteofheadache Statistics

pvalue Unstandardizedcoefﬁcient Oddsratio(95%CI)

Students Frontal 0.084 1.243 3.467(0.848---14.174)

Occipital 0.670 0.365 1.440(0.269---7.714)

Temporal 0.914 −0.105 0.900 (0.133---6.080)

Housewives Frontal 0.823 0.154 1.167 (0.303---4.499)

Occipital 0.699 0.300 1.350 (0.295---6.183)

Temporal 0.940 −0.065 0.938(0.173---5.070)

Table4 Statisticalrelationbetweenoculo-visualanomalyandreportedsiteofheadache.ThestatisticsincludesPearson2 testsandoddsratiowith95%conﬁdenceinterval(CI).

Ocularanomaly Siteofheadache Statistics

Frontal Occipital Total Oddsratio(95%CI) p-Value

BVA 5 0 5 1.429(1.130---1.806) 0.155

RE 22 9 31

BVA,binocularvisionanomalies;RE,refractiveerror.

ofthe patientshadBVA leadingtooccipitalandtemporal headache.

Visualacuityandrefractiveexamination

Mostofthepatientshadnormaltosubnormalvisualacuity (Table5).Forty-fourpercentofthepatientshadrefractive error. All of them were corrected with appropriate pres-criptionwhichwasevidentthroughretinoscopy.Knowneye problemwas signiﬁcantly associatedwith refractiveerror andBSVanomalies(2

1=11.225,p=0.001).Eightearly pres-byopeswereprescribedthenearvisionglasses.

Table5 Summarytable.

Ocularmorbidity Frequency(%)

Visualacuity 100(100) 6/6---6/9 88(88) 6/12---6/60 10(10) <6/60 2(2) Refractiveerror 44(44.00) Hyperopia 12(27.27) Myopia 4(9.09) Astigmatism 28(63.63)

Binocularvisionanomalies(nonpresbyopic, N=80)

23(28.75) Convergenceinsufﬁciency 13(16.25) Poorfusionalvergence 9(11.25) Intermittentexotropia 1(1.25)

Others 7(7)

CVS 5(5)

Establishedglaucoma 1(1)

Glaucomasuspect 1(1)

BinocularVisionAssessment(BVA)

Orthopticexaminationwascarriedouton80non-presbyopic patients (Table 5). Seventy-one patients hadorthophoria; eighthadexophoriawithgoodrecovery.Fusionalvergence satisfyingSheard’scriteriawasmeasuredin71(89%).

Discussion

The prevalence of refractiveerrors (44%)in this group of thiscommunitywashigherthanthatreportedbydifferent authors ofother partsof theworld. Cameron23 _estimated

a low prevalence of refractiveerror related headache in a sample of 50 patients referred for ocular examination and Jain et al.24 _in _an _{observational} _study _conducted _in

India reported only 1.48% (of 202 patients)prevalence of refractiveerrorsinheadachepatients.Thesediscrepancies arefromthepatientenrolment.Theyhaveincludedevery patient of headache without speciality consultation. We observed28.75%patientswithheadachetohavepoor binoc-ularityofwhich16.25%(outof80non-presbyopicpatients) had receded Near Point of Convergence. This prevalence of convergence insufﬁciency is less than that of Gupta etal.25 _in _India _(49%),_Romania26 _(60.4%) _and_Patwardhan

and Sharma27 _(71.4%) _in _India. _These _{discrepancies} _might

be because of the different working environments of the patients. Gordon15 _also _cites _poor _binocular _status _as _a

potentialsourceofheadache.The literaturealsoprovides anecdotalsupportforthehypothesisthatcertain optomet-ricanomalies,especiallydecompensatedexophoria,maybe prevalentin headache.28 _A_large _number _of _patients_with

BSV anomalies in our study might be correlated to these observations.AlthoughthesedataimplythatNepalese peo-plefromruralareashavemoreocularproblemsleadingto headache,thedifferingprevalenceofthesemorbiditiesin differentcountriesmustbeaccountedforeconomical and

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psychological well being because these people might be exaggeratingtheirheadachesymptoms.Moreover,these dis-crepanciescouldbebecauseofthepatientenrolmentbeing veryselectiveinourstudywhereallthenonocularcauses ofheadachewereexcluded.Thehigherproportionof peo-plewithpreviouseyeexaminationinthisstudysuggeststhat thesepeoplethinkthattheireyesareculpritbehindtheir headache.Ourobservationsfortheprevalenceofheadache inuncorrectedrefractiveerrorsareinaccordancewiththat ofGil-GouveiaandMartins.14

This study provides further evidence that headache is morecommon infemale (p>0.001)similarto observation noted by Hendricks et al.29 _We _observed _that _every _six

patients out of ten have headache in the non-presbyopic adultgroupwithfemaleshavingmorethantwofold(2.33 fold) prevalence over male. Headache prevalence in this particularagegroupmightbebecauseofthepsychological stress caused by educational pressures for career devel-opment, emotional factors and family conﬂicts. Female preponderancecouldbebecauseoftheculturally set fac-torsandtheeffectsofmaledominatedsocietywhichmay leadtopsychologicalstress.30_Prevalence_rate_of_headache

has been observed to increase at the age of 13, particu-larlyamonggirlsbecauseofpuberty.4_In_our_study,_patients

in theschoolage comprisedof 20%.Headache inthisage group could bebecause of home and school environment whichputspressureforbetterperformanceinthestudies.

Someauthorsbelievethatspectaclesforthecorrection oflowdegreeofrefractiveerrorsisjustaplacebo15 _while

others claim it to be an effective method to ameliorate headache symptoms.29 _Our _results _also _suggest _the _claim

that low degrees of refractive errorsare associated with headachebecause88%ofthesepatientshadbeen present-ingvisualacuityof6/6and6/9.Onehypothesisstatesthat even the minor degree of astigmatic errors of refraction causes changes tovisual perception that alter the hyper-excitability in the visual cortex of the brain of headache sufferers.30 _Astigmatic_blur_may_exacerbate_the_perception

ofstripedpatternswhicharethoughttobeimportantinthe visual triggers of different types of headaches.31 _Another

hypothesis couldbe the neurotic personality traits which meanthatthepatientswithheadachedemandlowdegrees ofrefractiveerrorcorrection.32,33_It_is_possible_that

refrac-tiveerrorcouldhaveanassociationwithheadachehavingno impactontheseveritybuttheuncorrectedrefractiveerror exacerbates the headache symptoms.2 _We _have _observed

that theprevalence of astigmatism is higher than thatof hyperopiaandmyopia(63.63%,27.27%and9.09%).Ourstudy is in an agreement withthat of Patwardhan and Sharma whoclaimthesametrendinrefractiveerrorprevalencein headachepatients.27

The prevalence of computer vision syndromeobserved in our study (13%) is similar (9---12%) to that of the United States.28 _The _{patho-physiology} _of _headache

asso-ciated with prolonged VDU use resides within the ocular surface abnormalities, accommodative spasms, dry eyes and/orextra-ocularetiologies.34

Thefirstlimitationofourstudyisthatourpatientswere recruitedfromahospitaloutpatientclinicpopulationwith asmallsamplesize,sotheseresultsmaynotbe represen-tativeofthegeneralpopulationasawhole.Second,wedid notperformvisualfieldtestingasallthepatientswerefirst

examinedbydifferentcategoryofmedicalspecialistswhich examineheadachepatientsandallthepossiblenonocular causeswereruledout.Visualﬁeldtestinghasacorerolein thedifferentiationofocularandnonocularheadachewhich needstobeincluded amongthewiderangeofophthalmic tests.Third, the inadequatepatient masking is the prob-ablereasontorevealhigh prevalenceofocular morbidity. Ourstrongpointistheveryselectivepatientenrolment.We haveexcludedeveryheadachewithknownetiology.

Inconclusion,thisstudyprovidestheevidencethat ocu-lar morbidities and headache symptoms are linked very frequently.Thoroughrefractiveevaluationandbinocularity evaluationareimportantinheadache.Itisimportanttoget agoodheadachehistorysothatpatientcanbereferredto theappropriatespecialistforthemanagementofheadache andhenceliveabetterqualityoflife.

Conﬂicts

of

interests

None.

Acknowledgments

We would liketo acknowledge Asst. Prof Dr Pankaj Pant; MD(General Medicine),Dr Bikash Shrestha; MD(ENT) and DrAjayRisal;MD(Psychiatry)forhelpingusinco-managing thepatients.WewouldliketoacknowledgeMrRoshanKumar Mahato;BachelorinPublicHealth,forhelpinguswith sta-tisticalanalysis.

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