we evaluated the choroidal thickness of healthy children 18 years of age through edi sd - oct . this prospective study was performed at our institute , from june 2012 to august 2013 . prior approval from the institutional review board of the institute was taken , and informed consent was obtained from the parents or guardians of each participant . only children aged 5 years or older were included because younger children were considered unable to cooperate for sd - oct examination . exclusion criteria included high myopia ( > 6 d ) or hyperopia ( > + 4 d ) ; eyes with any ocular disease or axl > 25 mm or < 20 mm ; any retinal or retinal pigment epithelium ( rpe ) abnormality detectable on oct scan or vitreoretinal disorders ; poor image quality because of unstable fixation ; evidence of amblyopia or strabismus ; history of systemic disease or systemic medications with known ocular effects ; history of any ocular surgery / injury , strabismus , amblyopia , congenital cataract . all participants underwent a comprehensive ophthalmic examination including visual acuity testing using , slit - lamp biomicroscopy , intraocular pressure measurement using goldmann applanation tonometer , dilated fundoscopic examination , and cycloplegic refraction with cyclopentolate hydrochloride 1% eye drops . axl measurement was performed using ocular biometry ( iol master ; carl zeiss meditec , jena , germany ) . the sd - oct scans were obtained using cirrus high - definition ( hd)-oct ( carl zeiss meditec , inc . , scan 3 of the 5 , which passes through the fovea and was used for all the measurements . only scans with a signal strength of more than or equal to 6 were used for analysis . using the cirrus linear measurement tool , single observer measured choroidal thickness , which was defined as the vertical distance from the hyperreflective line of the rpe along the direction of the scan , to the hyperreflective line of the inner surface of the sclera , at 500 microns intervals temporal and nasal from the fovea , up to 2500 microns as published in the literature . as both eyes of most subjects were included for analysis , the correlation between the two eyes of the same subject was adjusted using generalized estimating equations ( gee ) during the calculation of summary descriptive parameters . multivariate models adjusted using gee methods were fit to assess the effects of age , gender , axl , and spherical equivalent ( seq ) on the choroidal thickness measurements . statistical analyses were performed using commercial software ( stata version 12.1 ; statacorp , college station , tx ) . the alpha level ( type i error ) the sd - oct scans were obtained using cirrus high - definition ( hd)-oct ( carl zeiss meditec , inc . , scan 3 of the 5 , which passes through the fovea and was used for all the measurements . only scans with a signal strength of more than or equal to 6 were used for analysis . using the cirrus linear measurement tool , single observer measured choroidal thickness , which was defined as the vertical distance from the hyperreflective line of the rpe along the direction of the scan , to the hyperreflective line of the inner surface of the sclera , at 500 microns intervals temporal and nasal from the fovea , up to 2500 microns as published in the literature . as both eyes of most subjects were included for analysis , the correlation between the two eyes of the same subject was adjusted using generalized estimating equations ( gee ) during the calculation of summary descriptive parameters . multivariate models adjusted using gee methods were fit to assess the effects of age , gender , axl , and spherical equivalent ( seq ) on the choroidal thickness measurements . statistical analyses were performed using commercial software ( stata version 12.1 ; statacorp , college station , tx ) . the alpha level ( type i error ) mean age ( mean  standard deviation ) of the subjects was 11.9  3.4 years ( range : 518 years ) . the mean axl was 23.55  0.74 mm ( range : 21.1224.98 mm ) and mean seq was  0.5  1.09 d. all patients were phakic . mean subfoveal choroidal thickness was 311.2  45.19 m ( range : 185396 m ) . when compared between two eyes of one patient , there was no significant difference in choroidal thickness at all locations . maximum choroidal thickness was noted subfoveally and gradually decreased as the distance from the fovea increased ( p < 0.00001 ) . nasal choroidal was found to be thinner than the temporal choroid ( p < 0.00001 ) . mean choroidal thickness at various locations from fovea in this study , age and axl showed significant negative correlation with choroidal thickness on univariate analysis whereas on multivariate analysis only axl showed a significant negative correlation . there was no significant difference in choroidal thickness between the males and females [ table 2 ] . correlation between subfoveal choroidal thickness and age , spherical equivalent and axial length relationship between various factors on the subfoveal choroidal thickness the development of normative choroidal thickness profile is necessary to make the diagnosis of the choroidal abnormalities . to the best of authors knowledge , this is the first study , which reports normative choroidal thickness profile in healthy indian children and studies effect of various factors affecting choroidal thickness using sd - oct [ table 3 ] . we found the thickest choroid at the subfoveal area , and temporal choroid was thicker than nasal choroid . comparison of present study with previously published literature on choroidal thickness in healthy children we report the negative correlation of age with choroidal thickness in indian children . our unpublished data revealed that the mean subfoveal choroidal thickness in 3 decade was 294.8  46.5 microns and that of in 8 decade was 249.6  36.0 microns . our present study reports that the mean choroidal thickness of children ( 518 years ) of 311.2  45.19 microns was significantly more ( 0.001 ) than adult age group . however , ruiz - moreno et al . reported no difference in choroidal thickness in children compared to adults . the reason for this discrepancy could be manual measurements of choroidal thickness . significant negative correlation has been seen between axl and choroidal thickness in the previous studies done in adults as well as in the pediatric population , similar to the present study . in contrary , park et al . found no correlation between axl and choroidal thickness . ruiz - moreno et al . did not include axl in their analysis , which is one of the very important factors to affect choroidal thickness . in our study , we did not find the difference in choroidal thickness between males and females , similar to previous reports . however , mapelli et al . recently reported a thicker choroid in females with slight significance ( p = 0.056 ) . in contrary , adult men have been reported to have thicker choroid than adult females . reason for this discrepancy in reports and the biological significance of choroidal thickness with regards to gender remains unclear . we observed that healthy indian children have slightly thinner choroid compared to french and korean children , but thicker than japanese children , which could be due to ethnic differences or different devices used for choroidal scans . however , there are no studies comparing choroidal parameters in various ethnic groups . in our study , choroidal thickness measurements were not performed at the same time of the day in all children , therefore , our results are affected by the diurnal variation as reported previously . we did not perform a topographic profile of choroidal thickness on superior and inferior quadrants . furthermore , our study does not provide data about children below 5 years of age due to technical difficulties in obtaining scans in younger children . this database could be useful for future studies evaluating choroidal changes in various chorioretinal disorders . future studies including longitudinal follow - up of children since birth using hand - held sd - oct instruments will give more information regarding the trend in choroid thickness with normal development of children .
purpose : the purpose was to study choroidal thickness and its profile based on location in healthy indian children using enhanced depth spectral - domain - optical coherence tomography ( sd - oct).methods : in this cross - sectional observational study 255 eyes of 136 children with no retinal or choroidal disease were consecutively scanned using enhanced depth sd - oct . 
 eyes with any ocular disease or axial length ( axl ) > 25 mm or < 20 mm were excluded . 
 a single observer measured choroidal thickness from the posterior edge of the retinal pigment epithelium to the choroid / sclera junction at 500-microns intervals up to 2500 microns temporal and nasal to the fovea . 
 generalized estimating equations were used to evaluate the correlation between choroidal thickness at various locations and age , axl , gender and spherical equivalent ( seq).results : mean age of the subjects was 11.9  3.4 years ( range : 518 years ) . 
 there were 62 females and 74 males . 
 the mean axl was 23.55  0.74 mm . 
 mean subfoveal choroidal thickness was 312.1  45.40 m . 
 choroid was found to be thickest subfoveally , then temporally . 
 age , axl and seq showed a significant correlation with choroidal thickness , whereas gender did not affect choroidal thickness.conclusion:our study provides a valid normative database of choroidal thickness in healthy indian children . 
 this database could be useful for further studies evaluating choroidal changes in various chorioretinal disorders . 
 age and axl are critical factors , which negatively correlated with choroidal thickness .