I have a patient who wants who has successfully worn single vision soft contact lenses for many years. He is now presbyopic and wants to try soft progressive lenses. He works a lot with paper and electronic documents and needs the best possible vision at near. What is the best way to ensure the best possible near vision?
Accurate refraction is very important. Take your time to find the maximum plus or minimum minus that gives the patient acceptable distance vision.
For patients with less than 1.00 DS of astigmatism calculate the spherical equivalent. Place this prescription in a trial frame, and push the plus.
Determining eye dominance is also important. There are several types of eye dominance. Determining sensory eye dominance rather than sighting dominance is the most effective way to achieve successful fitting of soft progressive lenses.
Use a handheld +1.50D or +2.00D lens, alternately placed over each eye (while best corrected) to determine which position creates the least blur with both eyes open. The non-dominant eye is the one that when the +1.50 DS is placed over it results in the least blurred distance vision with both eyes open. The dominant eye is the one that results in the most blurred vision with both eyes open when the +1.50 DS lens in place over it. This can help determine whether more plus or higher add powers should be used in the non-dominant eye to improve near vision without compromising distance vision.
Also, if you are using centre-distance and centre near progressive lenses, place the centre-distance lens in the dominant eye and the centre-near lens in the non-dominant eye. This will help provide the best possible distance vision and the best possible near vision
With appropriate lighting, test the patient’s vision using a mobile phone or a tablet device or some of their work documents rather than a clinical test. Check only both eyes open visual acuities at distance and near after allowing patients a few minutes to adapt. Let patients know that some shadowing or mild blur may be apparent for a few weeks.
My preference is to review in a week after first dispensing to take clinical measurements but also to reassure, and to offer advice and encouragement. In my experience most but not all patients obtain satisfactory vision with soft progressive lenses.