Patient Care

GDx Nerve Fibre Layer Analysis

This recent innovation allows measurement of the thickness of the nerve fibre layer, which is the part of the retina that is first affected in the disease of glaucoma. The nerve fibril layer defect is detected long before any defect is noted in the function of the eye including the field examination. This test may help in the early detection of significant damage caused by glaucoma and help in the follow up of these patients. The test involves the use of scanning laser that passes through the nerve fibre layer and in the process undergoes a process called retardation. By measuring the extent of retardation the machine calculates the thickness of the nerve fibre layer.

This is an advanced technology in ultrasonography, which permits high-resolution pictures of the front of the eye. The technology enables the measurement of the angle of the eye, which is otherwise not accessible for measurement. The angle of the eye is the path through which the fluid in the eye finds access outside. The angle can become closed in certain individuals. This propensity to closure of the angle can be more adequately predicted using this advanced testing. Following injury to the eye, sometimes abnormal communications develop leading to excess drainage of fluid and resulting in soft eyes. These abnormal sites can be best identified by UBM.

These two tests enable the measurement of misalignment between the two eyes. This type of problem leads to a condition of double vision in a patient. The extent of the double vision and the direction in which it is maximal can be charted by using these two tests. The tests are done using red and green goggles where in one colored glass is placed in front of one eye and the other in front of the other.

Contrast sensitivity is the visual ability to see objects that may not be outlined clearly or that do not stand out from their background. The ability to see a shade of gray on a white background or to see white on a light gray background declines with age. Cataracts, diabetic retinopathy and other conditions can also affect contrast sensitivity.