Ophthalmic Causes of Headache among Patients Attending Tertiary Care Center in Kathmandu, Nepal

The purpose of this study was to evaluate the ophthalmic causes of headache among patients attending tertiary care hospital. This was a descriptive, cross sectional hospital-based study. One hundred and thirty-two patients with ocular cause of headache excluding primary headache and pediatrics patients during one year were included. Detail ocular examination was done including visual acuity, refraction, binocular vision assessment like convergence insufficiency and fusional insufficiency, anterior and posterior segment examination. Among headache patients, female was 106 (80.3%) and male was 26 (19.7%). The prevalence of headache in female was 6.9% and in male was 2%. Headache was more common in age group 18-29 (59.8%). The mean age of presentation was 29.9 ± 10.2 years (range 18-61 years). Out of 132 patients with headache, 104 (78.8%) had refractive error, 15 (11.4%) had fusional insufficiency, 6 (4.5%) had convergence insufficiency, 10 (7.6%) had anterior segment diseases and 5 (3.8%) had posterior segment diseases. Among refractive errors, both eyes astigmatism was the commonest 48 (36.5%) followed by both eyes simple myopia 44 (33.4 %) which was statistically significant with ocular headache (p=0.000). Ocular anomalies other than refractive error may coexist with headache complaints. Therefore, thorough ocular examination should be done in all patients suffering from headache.


Introduction
Headache is defined as continuous or prolonged dull pain in the region of the head. Headache in itself is not a disease but a symptom of a disease. Headache can be sight or life threatening if not treated promptly. It can be primary or secondary. Primary headache is not associated with underlying diseases whereas secondary headache is associated with underlying diseases. Among secondary headache, ocular cause is the most common cause of headache. Due to a close link between the eyes and headaches, Ophthalmologists are usually the first physicians to evaluate the patients with headache and headache associated visual disturbances. Most of the cases of ophthalmic origin is refractive error who first present to neurologists and undergo unnecessary investigations leading to waste of time and money which could be avoided if an Ophthalmologist is consulted initially. 1,2 In Ophthalmology Out Patient Department (OPD), the most common cause of headache is refractive error followed by other ocular causes. Therefore, the purpose of this study was to evaluate the ophthalmic causes of headache in patients attending the Ophthalmology OPD.

Materials and methods
The study was conducted in Ophthalmology OPD at Nepal Medical College Teaching hospital (NMCTH) from January 2020 to December 2020. One hundred and thirty-two patients with ocular cause of headache were studied. Sample size was taken using the formula Z 2 pq/d 2 = (1.9) 2 X 36 (100-36) /8 2 = 3.61 X 36 X 64/64 = 129. This was a descriptive, cross sectional hospital-based study. Patients above 18 years who presented to OPD with complain of headache was included in the study. Patients with primary headache, pediatric patients and with history of ocular trauma were excluded. Informed consent was taken from each patient. Ethical clearance was taken from Nepal Medical College-Institutional Review Committee (NMC-IRC). All patients underwent a complete ophthalmic examination including visual acuity, refraction, orthoptic evaluation including measurement of near point of convergence and range of fusion which was measured by prism bar.
Diagnosis was made as defined below: Convergence insufficiency: Near point of convergence 3 (NPC) >6 cm and fusional insufficiency 4,5 is defined as <15 Prism diopters base out prism and <8 prism diopters base in prism.
Anterior segment by slit lamp examination, posterior segment evaluation by +90D lens and other examinations such as Intraocular pressure measurement by applanation tonometer, neuro-ophthalmological examinations were performed as when needed. Data was collected in research proforma. Data entry and statistical analysis were done using SPSS version 16. The chi-square test was used to find the association between categorical variables. P value <0.05 was considered significant.   times more than the male. The prevalence of headache in female was 6.9% and in male was 2%. Headache was more common in age group 18-29 (59.8%) and then 30-39 (22%) ( Table  2). The mean age of presentation was 29.9 ± 10.2 years (range 18-61 years). Fifty-eight patients with refractive error were in age 18-29   and compound myopic astigmatism in 2 (1.5%). In Left eye, simple myopia and simple myopic astigmatism was seen in 3 (2.3%) respectively, 4 (3%) compound myopic astigmatism and 1 (0.8%) mixed astigmatism was seen (Fig. 1).

Discussion
The present study showed that among headache patients, female was 106 (80.3%) and male was 26 (19.7%). Female patients were 4 times more than the male. The prevalence of headache in female was 6.9% and in male was 2%. This finding was similar to other studies done by Garg P 6 , Hendricks et al 7

and Marasini
S et al 8 with females having more than twofold prevalence over males. Some other studies also showed females were more in number (59.4%) than males (41%). 9,10 In this study headache was more common in age group 18-29 (59.8%). The mean age of presentation was 29.9 ± 10.2 years (range 18-61 years) was statistically significant with ocular headache (p=0.00). In Garg P 6 study 45.2% patients were young adults of 21-30 years. Similar findings were reported by Dhir 11 and Ahmed and Zuberi 12 who found the maximum incidence of headache in the age group of 20-30.
This study showed majority of cases 31.8% were students followed by 28% home maker and 13.6% were businessmen which showed statistically significant association between occupation and headache (p=0.000 The Prevalence of ocular headache in our study was 4.7% which was less than that reported by other studies. The prevalence of headache in general population is thought to around 48.9%. 19 Masoodi et al 20 reported that the overall prevalence of any headache was 66.2 % with female preponderance. Prevalence of headache from a nationwide study in Nepal has shown the prevalence to be 85.6%. 21 But the literature for a strong association between oculo-visual problems and headache is weak. 22 This could be because of the patient enrolment being very selective in our study where all the non-ocular causes of headache and pediatric patients were excluded. Headache is more prominent in low grades of refractive error than in high errors and more prominent in astigmatism in comparison to myopia and hyperopia. The constant effort exerted in order see clearly causes eye strain which results to headache. In present study, the prevalence of refractive error was 3.7% among headache patients which was more (1.48%) than prevalence of refractive error in headache patients done in Jain AP study. 23 26 Any ocular inflammatory disease and acute rise in intraocular pressure may cause pain in and around the eye and also cause headache. 27 In our study posterior segment diseases included 3 (2.3%) cases of optic neuritis and 2 (1.5%) of papilledema which was similar to Parajuli et al 25 study where 1% of optic neuritis and papilledema was noted.
In conclusion, refractive error was found to be the most common cause of ocular headache. Among refractive error astigmatism was the commonest cause of ocular headache. So, careful ophthalmic examination including