GB2332062A - The digital display trial frame - Google Patents

Abstract

An ocular trial frame apparatus for the measurement and display of inter-pupillary distance and the astigmatism angle of the eyes, comprising measurement means to provide digital signals which are indicative of inter-pupillary distance and astigmatism angle and means to display said measurements.

Description

1 2332062 The Oculus Full Eye Trial Frame Digital ( series 1) Display

Trial Frame The purpose of this invention is to provide a Digital measurement of the pupillary distance p.d. and of astig[natism.

The current trial frame allows the measurement of the pupillary distance (p.d) Distance between the pupil centres of the two eyes ( in mm), and also used to centre the lenses in a frame to provide optimal vision through the lenses. And the Astigmatism (i.e. the curvature of the cornea / lens of the eye), to be recorded in 180 degree fashion.

At present all trial frame measurements are recorded in an Analogue style. The disadvantage of this is:

( a) At high Astigmatism an accurate recording of the degree is essential, the p.d has to be accurate to allow optimal vision through the lenses. The Analogue markings are printed on the unit, therefore, only a objective recording is made. b With wear and tear the print of the nun for p.d and degree for astigmatism disappears making it difficult to give an accurate recording, therefore an error of a couple of degrees for high astigmatism leads to distortion of vision and thus wasted time and money.

2 This invention involves a Digital measuring of the p.d and of the Astigmatism.

Figure 1 Shows Trial frame in Frontal View.

Figure 1 A Shows a cross - section of the top of the unit where p.d is measured.

Figure 2 Shows the Trial fl-ame in Side View Figure 3 Shows Plan View of the lens holder.

Figure 4 Shows ARM of the Trial fl-ame.

Referring to figure 1 The rotation of B show: When rotated clockwise the lens holder moves nasally. The lens holder has a metal conductor which is in contact with the metal strip at the top of the unit Figure 1 A. When rotated anti - clockwise the lens holder moves temporally.

When the lens holder is rotated clockwise, there is a small current passing through. When rotated anti - clockwise the lens holder moves temporally and a larger current passes through. Depending upon the amount of current that passes through and, therefore, position of the lens holder, the current is converted into the p.d measured in mm.

3 Astigmatism Measurement The rotation of the knob A in figure 1 clockwise, allows the lens holder to rotate clockwise and vice - versa.

Figure 2 The side view shows that a battery can be inserted into the ARM, figure 4 of the fl-ame, which also has a switch. The switch allows the unit to be switched on off figure 4, number 11.

Figure 3 When the lens holder is rotated clockwise this causes the metal conductor, 3 a, to remain in contact with the metal strip, and the metal conductor, 3b, not to be in contact.

When lens holder rotated anti - clockwise, the metal conductor 3 b, rotates anti - clockwise and remains in contact with the metal strip, and 3a, doesnot.

Figure 4 Shows where the battery is inserted and the position where the unit can be switched on/ off. The conversion into degrees is similar to that for p. d.

When placing the lens into the lens holder it can be lined - up with the GROOVES, figure 1 number 1, on the unit.

The lens for the Astigmatism has marking on them indicating the direction of the lens cylinder. This marking is lined - up into the lens holder with the groove and 4 then rotated to the desired degree. There are two grooves, one at 90 degrees and the other at 180 degrees.

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Claims (1)

1. The Digital display trial fi-ame allows an exact recording of the Pupillary Distance (p. d) in mm, and that of the Astigmatism in degrees.