|LETTER TO THE EDITOR
|Year : 2011 | Volume
| Issue : 4 | Page : 326
Tarannum Mansoori1, Kalluri Viswanath1, Nagalla Balakrishna2
1 Department of Glaucoma, Pushpagiri Eye Institute, Marredpally, Secunderabad, India
2 Department of Biostatistics, National Institute of Nutrition, Hyderabad, India
|Date of Web Publication||11-Jun-2011|
Department of Glaucoma, Pushpagiri Eye Institute, 241, Uma plaza, 10-2-342, Road No. 9, West Marredpally, Secunderabad - 500 026, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Mansoori T, Viswanath K, Balakrishna N. Authors' reply. Indian J Ophthalmol 2011;59:326
We thank Gundogan et al for their interest and valuable comments in response to our article 'Optic disc topography in normal Indian eyes using spectral domain optical coherence tomography. 
Gundogan et al mentioned that the article reports insignificant relations between the optic nerve head (ONH) area and the cup/disc ratio. However, we reported a significant positive correlation between the disc area and the cup/disc horizontal ratio, and the cup/disc vertical ratio and the cup/disc area ratio [Table 3]. 
We agree that the inclusion criteria of the study limited the refractive error within ± 3 diopter (D) for the sphere and within ±1.5 D for the cylinder. We appreciate that Gundogan et al have given an excellent example of how limiting the numerical values into a narrow range may mask the significant correlation. We agree that if the values are limited in such a way, the number of the participants should be increased in order to increase the reliability of the results. In the [Table 1] given by Gundogan et al, group 3 has seven values for each variable instead of eight, and hence, the total number of values is 22 and not 23 as mentioned.
It has been reported that ONH is large in high myopic eyes and small in highly hyperopic eyes.  However, in eyes with moderate refractive error, the ONH size is mostly independent of the refractive error . 
Jonas et al.  reported that the optic disc size depends on the refractive error, with an increase in disc size in high myopic eyes beyond - 8 D and a decrease in high hyperopic eyes beyond + 4 D. In our study, the refractive error ranged between ± 3 D in the sphere and for this range of refraction, the optic disc area did not show statistically significant correlation with the refractive error. Also, it was clearly mentioned that further studies are needed to determine whether ONH parameters differ in high myopic and hyperopic eyes. 
| References|| |
Gundogan FC, Tas A, Sahin OF. Optýc dýsc topography ýn normal Indýan eyes usýng spectral domaýn optýcal coherence tomography. Indian J Ophthalmol 2011;59:325-6.
Mansoori T, Viswanath K, Balakrishna N. Optic disc topography in normal Indian eyes using spectral domain optical coherence tomography. Indian J Ophthalmol 2011;59:23-7.
Jonas JB, Budde WM, Panda-Jonas S. Ophthalmoscopic evaluation of the optic nerve head. Surv Ophthalmol 1999;43:293-320.
Jonas JB. Optic disk size correlated with refractive error. Am J Ophthalmol 2005;139:346-8.