Anshu Sharma1, Sarita Aggarwal2, Varun Aggarwal3, Himanshu Sardana4, Rahul Sahay5
Myopia is a common optical aberration. Physiological myopia, by far the most prevalent, is less than -6D in magnitude and is considered a normal biological variation. Eyes that have errors greater than -6D are said to have high myopia. Pathological myopia is that type of myopia, which is accompanied by degenerative changes occurring particularly in posterior segment of globe. It is usually, but not invariably associated with lengthening of the anterior-posterior axis of eyeball and is usually, but by no means always progressive. It is probable that to some extent at any rate the two - the myopia and degenerative changes are independent, but are usually closely related.
MATERIALS AND METHODS
100 eyes of the 50 patients with myopia more than -6D attending the Outpatient Department of Ophthalmology at Santosh Medical College and Hospital, Ghaziabad, were examined. Keratometry was done to measure corneal curvature using keratometer. Ultrasound biometry was done using contact probe Biomedix A-Scan with digital display to assess axial length in all subjects in both eyes.
There were 100 eyes examined in this manner. 12 patients had unilateral high myopia, one patient had unilateral functioning eye and 38 patients had bilateral myopia.
A steady rise from 75% in the range of average axial length <23.5 mm to 100% in all eyes of average axial length of 23.5 mm and above was seen in eyes with crescent in this study. Chorioretinal atrophy was observed in 32 eyes of axial length >26.5 mm and was found more frequently with increasing axial length. Fuchs spots was seen in 13 eyes out of 39 eyes of axial length >26.5 mm and was seen more frequently with higher axial lengths. Lacquer cracks was seen in seven patients of axial length >28.5 mm. Posterior staphyloma was seen in two patients of axial length >25.5 mm and was less common than Fuchs spots and Lacquer cracks in a steady rise from 33% in the range of average axial length of 29.5 mm to 100% in all eyes of average axial length of >33.5 m. A proportion of asymptomatic high myopic subjects were found to have peripheral retinal degenerative and posterior pole chorioretinal lesions. As these degenerative changes may be associated with serious vision threatening complications, so these patients should be advised to seek ophthalmic care promptly should such symptoms arise.