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| OPHTHALMIC IMAGE |
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| Year : 2022 | Volume
: 2
| Issue : 3 | Page : 839 |
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Beam aberration through progressive glasses
Amber A Bhayana, Sudarshan K Khokhar, Priyanka Prasad, K Anshida
Department of Ophthalmology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi, India
| Date of Web Publication | 16-Jul-2022 |
Correspondence Address:
Dr. Amber A Bhayana
Dr. Rajendra Prasad Centre, AIIMS, New Delhi - 110 029
India
 Source of Support: None, Conflict of Interest: None
DOI: 10.4103/ijo.IJO_2734_21
How to cite this article:
Bhayana AA, Khokhar SK, Prasad P, Anshida K. Beam aberration through progressive glasses. Indian J Ophthalmol Case Rep 2022;2:839 |
A progressive,[1] presbyopic glass can be identified by the progressive magnification it causes to the letters seen across it (size increasing downwards) [Figure 1]a. This might be missed in case of small magnitude of near add where differential magnification might be difficult to identify. We describe a simple, novel, yet foo proof method to identify the glasses. The illumination beam from indirect ophthalmoscope (ideally symmetrically circular) [Figure 1]b when passed through the glasses manifests distortion in the inferior half [Figure 1]c. The distortion is alike when different colours of lights are used [Figure 1]d, [Figure 1]e, [Figure 1]f. The distortion is due to different converging powers in different zones of the glasses, the same factor being responsible for differential magnification. | Figure 1: (a) Reading letters through progressive glasses (note the increase in size of letters in downward direction); (b) Virgin beam from indirect ophthalmoscope (note the circular symmetry); the beam passed through progressive glasses show distortion for (c) white light; (d) blue light; (e) green light; (f) red light
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Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | |  |
| 1. | Wolffsohn JS, Davies LN. Presbyopia: Effectiveness of correction strategies. Prog Retin Eye Res 2019;68:124-43.  |
[Figure 1]
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