Ms Chan (F/46) came for eye examination end of last year, with complaint of blurry far & near vision with existing Single Vision, SV glasses of 3 years. She reported that her power in existing glasses is purposely lowered in right eye so that she can still manage to see near, without having to wear multifocal glasses.
Vision without glasses
R: cannot guess 6/60
L: cannot guess 6/60
Vision with existing SV glasses
R: -4.25/-1.25×10 (6/15-)
L: -3.75/-2.00×180 (6/7.5-)
Examination shows:
R: -5.25/-2.00×10 (6/6) [R: dominant right eye]
L: -3.75/-2.50×180 (6/6)
Add: +1.75 (N5@40cm)
We tried giving -0.25 on RE, but she did not like it
Other assessments show:
Examination of Eye Alignment/Vergence (Cover Test)
NMD @ Distance
small XP, fast to moderate recovery @ Near
(normal value: orthophoria/NMD-No Movement Detected or small XP, fast recovery)
EP = Esophoria is misalignment of the eye, eye is deviated inwards
XP = Exophoria is misalignment of the eye, eye is deviated outwards
Examination of Eye Alignment/Posture (Howell Card)
Distance: 2 XP (blue part)
Near: 10 – 12 XP (blue part)
(normal value: 0-1 EP or 0-3 XP @Distance and 0-6 XP @Near)
EP = Esophoria is misalignment of the eye, eye is deviated inwards
XP = Exophoria is misalignment of the eye, eye is deviated outwards
Ms Chan reported that her power in existing glasses is purposely lowered in right eye so that she can still manage to see near, without having to wear multifocal glasses. This may not be a good idea as it causes strain to our eyes systems. Imagine we work in front of computer, and our chair has got 2 or 3legs only, it wont give us a good support. So, how are we going to work effectively? One part of muscle is overworked while the other part is underworked to give the needed balance?
Same thing goes to our eyes.. give the power your eyes need.. is all the pamper they need from us. If you do not like to wear glasses, that is fine as everyone has our own preference. You let us know and we can prescribe contact lens for you. Not to give them suboptimal power or you are not wearing your correction at all. We must sayang our eyes, remember?☺️
Wearing suboptimal power causes strain to your eyes. Your eyes are used to working under the strenuous condition for years. Sometimes, when we optimise your power, your eyes may find it hard to regulate back to normal (eye systems may be haywire for a while) hence your difficulty in adapting to the new power.
Like in Ms Chan, we prescribe her with multifocal glasses of the new power and she returned to report about difficulty seeing near. We adjusted her power & changed to:
Modified power
R: -4.75/-1.75×10
L: -3.75/-2.25×180
Add: +1.75
With this power, she finally is able to wear her multifocal glasses already. But, she came months later, to let us know that her far vision is slightly blurry. We check her power again:
New power
R: -5.00/-2.00×10
L: -3.75/-2.50×180
Add: +1.75
And we will have a look at her near posture again & probably a full Binocular Vision, BV workout is in time now.
Finally, her eyes (after wearing close-to-optimum power) accept the optimum power when eyes are at ease. Give the cosy environment(optimum power) to our eyes like how we would love to unwind on our cosy couch chilling & doing what we love doing during our me time! Kannnn hehe