Indian Journal of Ophthalmology

ARTICLES
Year
: 1985  |  Volume : 33  |  Issue : 2  |  Page : 91--94

Correlation between central corneal thickness and curvature


A Panda, K Venkateswarlu, SK Angra, VK Kalra, Madan Mohan 
 Dr Rajendra Prasad Centre for Ophthalmic Sciences, A.I.I.M.S., Ansari Nagar, New Delhi, India

Correspondence Address:
A Panda
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, A I.I.M.S., New Delhi-110029
India




How to cite this article:
Panda A, Venkateswarlu K, Angra S K, Kalra V K, Mohan M. Correlation between central corneal thickness and curvature.Indian J Ophthalmol 1985;33:91-94


How to cite this URL:
Panda A, Venkateswarlu K, Angra S K, Kalra V K, Mohan M. Correlation between central corneal thickness and curvature. Indian J Ophthalmol [serial online] 1985 [cited 2024 Mar 28 ];33:91-94
Available from: https://journals.lww.com/ijo/pages/default.aspx/text.asp?1985/33/2/91/30828


Full Text

A significant correlation between corneal thickness and curvature are reported in the literature[1],[2],[3]. Most of the workers have failed to demonstrate significant correlation between central corneal thickness and curvature. How�ever, Hovding[4] has reported a weak correla�tion in these parameters, In this communica�tion we endeavoured to find out any existing correlation in our population.

 MATERIALS AND METHODS



200 eyes of 100 normal subjects, in the age group of 13-35 years were taken into the study. All the cases were randomly drawn from the out patient department with no refractive error. All the cases were subjected to the measurement of central corneal thick�ness and curvature Corneal thickness was measured with Goldman's pachometer No. I mounted on a Haag Streit 900 silt lamp. The correct corneal pachometer position was ensured by a method described by Stone[5]. The mean value of 3 measurements was recor�ded as the central corneal thickness.

The radius of curvature of the anterior central 3mm corneal surface was measured in two principal meridia using Javal-Schiotz keratometer. The mean values of 2 readings in each of the two meridians were recorded. Both the measurements (at the same sitting) were taken using the same instruments.

 OBSERVATIONS



The findings are as highlighted in [Table 1][Table 2] for right and left eye respectively. These parameters bear no significant difference bet�ween the two eyes. The values were compared with these in the literature [Table 3]. The coefficient of correlation both for right and left eye are evident from [Table 4]. No corre�lation exist between corneal thickness and curvature. [Table 4], but a definite correlation exists between horizontal curvature and vertical and mean curvature [Table 4],[Figure 1].

 DISCUSSION



The normal values of corneal thickness in healthy subjects as given in literature varies from 0.507 to 0.565[3],[6],[11]. As the same place was not assured in thickness measurement by pachometer, it was suggested by Mishima[6],[7],[12] that within this central 3 to 3.6 mm cornea the thickness is usually regarded as constant.

Several authors quoted varying values between these two figures. Our values of cor�neal thickness are slightly higher than the reported values from Western literature[2],[3],[6],[10]. The factors which contribute to the variation in measurement is individual end point varia�tion and different instruments and the techni�ques adopted. In this survey, the anterior surface of the epithelium of the lower section was aligned with the posterior surface of the endothelium of the upper section. This technique was adopted as it was felt that this represented the full thickness[1]. But this differs from the technique adopted by others who tried to align the whole of the epithelium with the whole of endothelium[7]. So when we of talk corneal thickness, it is always necessary to mention the instrument and the technique used for measurement. This might explain higher values in our study.

Our results show that there is no signifi�cant difference between the value in right and left eyes, 0.545 & 0.546 respectively, although earlier studies[2],[3] indicated that the left cornea is slightly thicker than the right cornea. The slight difference is said to be due to the angle Kappa [12],[13], causing a slight decentering of the measurement of corneal thickness. Almost all the studies conducted earlier on this subject have involved only the right eye[3],[7],[8],[9],[10],[11], except Kruse who found the thickness 0.004mm more in right eye than left[2]. How�ever, we have conducted the study in both eyes and did not find any significant difference in either eye.

In the earlier reports it has been reported that no correlation exists between central corneal thickness and central corneal curva�ture[3]. Our findings are in conformity with these reports. We found that there is definite correlation between horizontal and vertical curvatures of cornea.

 SUMMARY



The study was conducted on both eyes of 100 healthy subjects. Central thickness and central curvature of all the eyes were measu�red. No correlation could be found between these parameters. The values were similar in both the eyes but definite correlation exists between various (horizontal & vertical) curvatures of cornea.

References

1Tomlinson A., 1972, Acto Ophthalmol, 50: 78-82
2Krause Hansen F,1971, Acta Ophthalmol 49 : 82-89
3Lowe R., F., 1969, Brit J. Ophthalmol 53: 73-82,
4Gunner Hovding, 1983, Acta Ophthalmol 61: 461-466
5Stone J, 1974, Contact Lens Jour, 5 : 14-19
6Mishima, S, and Hedbys, B, 0, 1968, Arch, Oph�thalmol (Chicago) 80 : 710-713
7Maurice D, M, and Giardinic, A., A., 1951, Brit J. Ophthalmol 35 : 169.
8Lavergne, G, and Kelcom, J., 1962, Bull. Soc. Balge. Ophthalmol 131 : 323-333.
9Donaldson, D. D., 1966, Arch. Ophthalmol 76:25-31
10Martola, E. L. and Baum, J. L., 1968, Arch. Of Ophthalmol 79 : 28-30.
11Von Bahr, G., 1948, Acta. Ophthalmol 26 : 247-265
12Mishima, S., 1968, Survey Ophthalmol 13: 57-96
13Ehlers, N. and Krnsee Hansen. F., 1971, Acta.Ophthalmol 49 :65-81.