Year : 1983 | Volume
: 31 | Issue : 6 | Page : 705--707
Myopia in newborn
Ranabir Mukherji, Anita Roy, Sanat Kumar Chatterjee
Department of Ophthalmology Calcutta National Medical College, Calcutta, India
Department of Ophthalmology Calcutta National Medical College, Calcutta
|How to cite this article:|
Mukherji R, Roy A, Chatterjee SK. Myopia in newborn.Indian J Ophthalmol 1983;31:705-707
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Mukherji R, Roy A, Chatterjee SK. Myopia in newborn. Indian J Ophthalmol [serial online] 1983 [cited 2019 Nov 22 ];31:705-707
Available from: http://www.ijo.in/text.asp?1983/31/6/705/29305
The study of the refractive condition of the eyes of newborn babies is essential for the proper understanding of the changing pattern of the refractive state in the formative period of life. Though hypermetropia is the normal refractive condition in the newborn, the incidence of myopia at birth particularly in premature newborn babies has long been noted. It is sometimes regarded as a form of mild retrolental fibroplasia. From the embryological point of view, this type of myopia is associated with an immature eye and is due to some metabolic disturbances of the media of the eye which produce changes in axial length, corneal curature and index of refraction (Fletcher and Brandon, 1955). In most cases, However, low ametropia including myopia are biological variants rather than pathological.
MATERIAL AND METHODS
The cases for the present study were collected from the nursery of the Obstetric Department of the Calcutta National Medical College and Hospitals.
In this study a total of 1000 eyes of 500 newborn babies were examined of which 258 were males and 242 were females. 140 babies were premature and 360 were normal babies. Babies with birth weights of 2500 g. and below and also babies born at or before 37 weeks of pregnancy were included in the premature group.
After preliminary examination and selection of cases, phenylephrine hydrochloride (Drosyn) 5% were instilled two to three times into the eyes of the baby to dilate the pupil. Retinoscopy was performed with the help of streak retinoscope from a distance of 50 cm. The total refraction obtained. In cases of unequal refraction in the two eyes, ametropia with higher values determined the worse eye. In cases of mixed astigmatism the myopic axis was the determining factor (Mukherji & Seal, 1979).
Incidence Of 500 babies, only 44 were emmetropic (8.8%); 345 were hypermetropic including astigmatism (69.0%) and 111 were myopic including astigmatism (22.2%).
Degree of myopic: Degree of myopia in 222 myopic eyes is given in [Table 1]. The majority of the cases had low myopia i.e. under-5D (215 eyes or 96.8%). High myopia above-5D were observed only in 7 eyes (3.2%).
Incidence of Astigmatism:-79 eyes of 222 myopic eyes had some degree of astigmatism (33.6%).
Myopia in relation to sex:-Incidence of myopia in newborn males was 39.6 percent (88 eyes), compared to 60.3 percent in females (134 eyes).
Myopia in relation to birth weight:-Babies with lower birth weights were found to be more myopic than' those with higher birth weights [Table 2].
Myopia in relation to period of gestation:-It would be seen from [Table 3]. that babies born 'earlier were more myopic than those born at or near term.
Myopia in relation to mode of delivery:
The correlationship of themode of delivery with the incidence of myopia is given in [Table 4].
In the present series of 1000 eyes of 500 newborn babies, myopia has been found to occur in 22.2 percent cases. The incidence of myopia in newborn babies as observed by various workers very from 9 percent to 23 percent [Table 5].
In an earlier report, Chatterjee and Mukherji (1979) observed the 19.2 percent incidence of myopia in 500 eyes of newborn babies. The relatively higher incidence of myopia as observed in the present study may he clue to the inclusion of more number of the reason for increased incidence of myopia in new born has sometimes been thought due to changes in the metabolism of the growing lens with changes in its water content. Changes in the curvature of a rapidly developing cornea could also explain the high lincidence of myopia at birth. In an adult eye, a decrease of only 0.4 mm. of the anterior radins of curvature of cornea increases in myopia by 3D, whereas in the premature, a similar decrease will enhance the myopia by 16D (Fletcher and Brandon, loc cit). Changes in the curvature of the cornea depend upon the volume of aqueous humour, growth and elasticity of cornea and selera. In a prematurely born baby with immature eyes, changes of metabolism of the introacular sturctures like lens, aqueous and vitreous humour, retina etc.. may he responsible for excessive aqueous formation or inadequate drainage of aqueous. resulting in ahrnormal stretching of the ocular coats and consequently the myopia of prenurturity results.
Imperfect metabolic process in a developing eye may result in a change of refractive index and may he responsible, at least in part, for myopia by -16D in the premature (Fletcher and Brandon loc. cit.). Lomickova (1064). However, stated that the development of myopia in premature infants was connected with hypoxia of the imature retina rather than prematurity as such.
A study on refraction in 1000 eyes of 500 newborn babies (of which 259 were males and 242 were females) born in Calcutta National Medical College and hospital was performed. It was observed that 8.8 percent (44 babies) had emmetropia; 69.0 percent (345 babies) had hypermetropia and 22.2 percent (111 babies) has myopia.
It was seen that myopia was more common in premature babies.
Myopia was seen to occur more in females (60.4%).
Higher degree of myopia ((-5D) was rare (3.2%).
Myopia in newborn has got no relationship with mode of delivery.
We are grateful to Prof. A.K. Bose, Head of the Department of Gynaecology and obstetrics who has permitted us to collect the cases and to Prof. H.N. Ghosh, Principal of the Calcutta National Medical College for kindly allowing us to publish this report.
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