The Fan and block chart is similar to an astigmatism fan chart but additionally includes a block which contains an arrow at the center and two blocks of the line adjacent to the arrow which are perpendicular to one another.…
The astigmatism fan chart has line differences in 10 degrees intervals. Some charts have correcting cylinder axis marked in chart written at top of each spoke of line (Figure 1) and some charts just only represent the actual representation of…
It consists of a series of the number of lines of equal length from the center and pointing towards a number similar to the face of a clock. Gaps between two numbers are equal to 30 degrees. Before reading procedure…
Two of the most commonly used astigmatism chart are the Clock dial chart and the astigmatism fan chart. This test well controls accommodation as fogging is done prior and has an advantage over the Jackson cross cylinder where one of…
The Hirschberg test is a quick and easy objective method for the assessment of ocular alignment. It is also known as the corneal light reflex test as the observation is based on the judgment of the position of the corneal…
Worth four dot test is a subjective procedure test to evaluate the presence of fusion, suppression, diplopia and abnormal retinal correspondence. The test can be performed for both distance and near Procedure: Ask the patient these questions Interpretation All below…
The Bruckner test is a simple yet very useful objective assessment for diagnosing abnormalities of the eye and refractive errors. The ophthalmoscope light is shone onto the eye and the light reflected from the fundus is observed. The interpretation of…
The keratometer is a specialized instrument used by optometrists and ophthalmologists to measure the curvature of the cornea. This measurement is important because it helps optometrists/ophthalmologists diagnose and manage a variety of eye conditions, such as astigmatism and keratoconus. In…
A lensometer is an optical instrument that is used to determine the refractive power and the prescription of eyeglasses or contact lenses. It is a crucial tool in the field of optometry. Mainly used for measuring the back vertex power…
Retinoscopy is an optical diagnostic test used by eye care professionals to determine the refractive error of a patient’s eyes. It is a quick and accurate method of measuring the amount of correction required to produce a clear vision. The…
