GP Lens Case Grand Rounds Troubleshooting Guide – 19

Intermediate Presbyopia (Previous Soft or Monovision Wearer): Douglas P. Benoit, OD, FAAO

Background

Patient CB, a 52-year-old teacher, presented for routine eye examination. She had a history of soft toric lens wear for 11 years. She had observed decreased vision at near moreso than at distance, but overall vision was never as good as with her glasses. She had attempted monovision lens wear, but didn’t like the compromised depth perception. She did not desire reading glasses over her contact lenses. Also, she wanted an easier/cheaper care system than her present AOSept system.

Her current lenses were: CSI Toric 8.6mm base curve radius,14.0mm overall diameter; Powers: OD -4.00 -1.00 x 175 and OS -4.50-1.00 x 20. The vision at distance was: OD 20/25; OS 20/25-. Each lens centered well and had good movement.

Test Procedures, Fitting/Refitting, Design and Ordering

Manifest Refraction:

OD: -4.50 -0.75 x 165
OS: -4.00 -1.50 x 30
Add +2.00D OU

Keratometry:

OD: 41.50 @ 175; 42.62 @ 085
OS: 41.50 @ 010; 42.87 @ 100

Her right eye was dominant ad her palpebral fissure height was 11.5mm. Her upper lid overlapped the superior limbus by 2mm and her lower lid was positioned 0.5mm above the lower limbus. Her pupil diameter was 4.5mm in normal room illumination. These factors made the patient an excellent aspheric multifocal GP candidate. OD was dominant.

Ks: OD 41.50/42.62 @ 85; OS 41.50/42.87 @ 100, MCR OU.

External ocular health was normal. Palpebral fissure height was 11.5mm, upper lid was 2.0mm over upper limbus, lower lid 0.5mm above lower limbus. Pupils were 4.5 mm in average room light.These factors made the patient an excellent simultaneous vision GP candidate. The Essential GP (Blanchard Labs) lens was chosen and a diagnostic fitting performed without anesthetic.

Trial Lens Parameters:

OU 8.10mmBC
-3.00, 9.5mmLD
Series 2 Add

Ten minutes after insertion, tearing had subsided and comfort was good OU. Distance vision was: OD 20/20 with a -1.75 over-refraction; OS 20/20 with a -1.50 OR. Near vision was 20/20 OU with a +0.75 OR over the trial lens/distance OR combo. Each lens positioned superior-centrally with lid attachment. The OS lens was slightly higher in primary gaze. Movement was good in all positions of gaze, with good translation up on downgaze, OS > OD. Fluorescein evaluation showed slight apical clearance OD, central alignment OS, and good peripheral clearance OU. This arrangement actually worked to the patient’s advantage since the non-dominant OS lens would position slightly more into the Add area when looking down to read.

Resultant Lens Order:

Essential design in Boston EO material with Series 3 Add OU.
OD: 8.10mmBC, -4.75, 9.5mmLD
OS: 8.10mmBC, -4.50, 9.5mmLD

Patient Consultation and Education

As the lenses were being ordered, the possible need to change some parameters in order to optimize the fit and visual result was discussed. The patient also understood that several follow-up visits would be necessary. Upon dispensing, the lenses were comfortable after 3-5 minutes, and tearing was normal. Vision was 20/20 at distance and at near. Each lens positioned as the trial lenses had, and good movement in all positions of gaze was maintained. Fluorescein showed slight apical clearance OD, alignment centrally OS, and good peripheral clearance OU. The patient was instructed on proper care using the Boston Advanced Comfort Formula solution system. Insertion and removal was demonstrated and practiced by the patient. The patient was instructed on the need to increase wear time gradually, starting at no more than 4 hours on day one, and adding 2 hours per day to a maximum of 14 hours per day.

Follow-Up Care/Final Outcome

At the 10 day progress evaluation the patient was generally happy with her vision and able to wear the lenses 12-14 hours per day. She did note that in low light the near vision was slightly off, which she had been advised of at the each visit. Entering vision was 20/20 at distance and near. No change was found on over-refraction. The lenses had a superior-central, lid attachment position in primary gaze, with the OS lens slightly higher. Movement was good in all POG. Fluorescein showed slight apical clearance OD and central alignment OS, with good peripheral clearance OU. Subsequent follow-up exams yielded the same results.

Discussion/Alternative Management Options

This patient was a very good candidate for aspheric GP multifocals. The amount of cornea astigmatism and other physiologic attributes were ideal. Being a teacher, there was a need for intermediate vision as well as distance and near, which the aspheric multifocal can provide. By letting the OS lens ride slightly higher in primary gaze, it allowed the lens to translate up a bit more on downgaze, which can enhance near vision and the intermediate vision as well. A segmented/translating GP bifocal could also have been used, if near demands were high and intermediate vision was not as necessary. This patient’s lower lid position relative to the lower limbus would have been ample to allow for translation, especially if the lens was truncated. Had GP lenses proved intolerable, a soft, toric, bifocal/multifocal could have been used. These generally do not give the sharpness of vision that a GP lens can, and it can be more unstable. Also, the care can be more involved, which this patient did not want.

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