GP Lens Case Grand Rounds Troubleshooting Guide

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Early Presbyopia (Current GP Wearer): Douglas P. Benoit, OD, FAAO


Patient JM, a 43 year old homemaker, presented for a routine eye examination. The patient was a GP wearer for 26 years, who reported good comfort and wear times of 14-16 hours/day. Her distance vision was good, but near vision has been blurred for the past 10-12 months. The patient had attempted readers over the contact lenses but didn’t like the hassle of carrying glasses. She also was also not favorable toward the idea of monovision. She was, however, very interested in bifocal contact lenses. Her current GP lens parameters were:

Material: Boston ES
BCR: 7.50mm
Overall diameter: 9.0m
Power: OD –6.50D, OS –6.00D

Each lens positioned centrally with upper lid attachment. Movement was good in all positions of gaze. Fluorescein evaluation showed central alignment with good peripheral clearance OU.

Test Procedures, Fitting/Refitting, Design and Ordering

Manifest Refraction:

OD: -6.75 -0.75×85
OS: -7.00 -0.50×77
Add: +1.00 OU


OD: 45.50@180; 45.00@090
OS: 45.75@180; 45.62@090

This patient was right eye dominant.The vertical fissure diameter was 11.5mm with the upper lid overlapping the superior limbus by 2mm and the lower lid positioned tangent to the lower limbus. The pupil diameter was 4.5mm under normal room illumination.

Diagnostic Fitting:

Essential Xtra (Blanchard Contact Lens), an aspheric multifocal GP lens in the Boston XO material, was diagnostically fitted. The following lenses were selected OU:

BCR: 7.40mm
OAD: 9.20mm
Power: -3.00D
Series 2

She reported that the lens comfort was great. The distance visual acuity was OD: 20/20 with a –3.75D over-refraction; OS: 20/20 with a –3.50D over-refraction. The near visual acuity was 20/20OU with the above over-refraction. Each lens exhibited upper lid attachment and good movement in all positions of gaze. Slight translation was achieved with down gaze. Fluorescein showed slight apical clearance centrally with good peripheral clearance OU.

The Following Lenses Were Ordered:

BCR: 7.40mm
OAD: 9.20mm
Power: -6.75D (OD) & -6.50D (OS)
Essential Xtra Series 2

Patient Consultation and Education

Upon dispensing of these lenses the comfort was great and the visual acuity was 20/20 OU at distance and near. Each lens positioned and moved similarly to the diagnostic lenses.

Proper head positioning and the need to continue a normal blink pattern were discussed. The possible need to make lens exchanges was reviewed.

Follow-Up Care/Final Outcome

At 10 days the patient returned for a follow-up evaluation. She noted great comfort all day and great vision at all distances. There was no spectacle blur noted after lens removal.

Discussion, Alternative Management Options

This patient was a perfect candidate for a GP multifocal. She was already an adapted GP wearer and had anatomy that favored an aspheric lens design. With time, the add “Series” can be increased to improve near vision as needed. This patient could have also been successful with a segmented design, especially if there was high visual needs at any distance. A soft, multifocal could also have been used. The vision is generally not as good as with GP lenses and the care is sometimes more involved that with GP lenses. This patient desired the easy care and longer lens life of the GP lens and has been very successful.

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