15. Prescribing monovision specs

You think your patient needs bifocal/varifocal spectacles for your patient but he is insisting on monovision lenses. What do you prescribe?

Scenario

Brendan Davis, aged 63, comes to you for a routine eye examination after his wife has been nagging at him to have his eyes tested. He has not had his eyes examined before, and has been wearing ready made spectacles +4.00 for several years. He is having no particular problems with his eyes and does not drive. You find: 

R Unaided vision 6/60 Rx +4.25/-0.50 x 75 VA 6/6+
L Unaided vision 6/24 Rx +2.00/-0.50 x 90 VA 6/6+
Reading add +2.25 gives N5 binocular. 

He is orthophoric for distance and has approx 5 prism dioptres of exophoria for near, which is compensated. Fundal examination is normal. Media are clear and you find CDRs of R 0.3 and L 0.35, IOP is R and L 15mmHg by NCT and central visual field testing is normal. 

You explain to Brendan that he needs spectacles for distance and for reading and you recommend he has bifocals or varifocals so he still only has one pair of specs. His friend has had bifocals and fell down the stairs with them, and he does not wish to spend out on varifocals. He is therefore adamant that he wants just one pair of single vision specs with the right eye corrected for distance vision and left eye for near, as he has in his ready mades. 

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