GP Fitting Case 1 - Discussion Item 3

After reading the Patient History, read the Discussion Items below. To test your understanding of this case, click on the word "select" to read the reasoning behind each choice.

Patient History: 16 y/o female student has never worn contact lenses. She plays no extra curricular sports, and her mother wears GP lenses. No contraindications for lens wear.

Spectacle Rx	OD -2.00 -0.75 x 180 OS -2.25 -1.00 x 180
Corneal Measurements	OD 43.50/44.25 @ 90 OS 43.25/44.25 @ 90
Ocular Measurements (OU)
Corneal diameter	11.5mm
Pupil	4.0mm
Fissure width	10.5mm

Discussion Item 3: Based on what you know about this patient, design an initial diagnostic lens for the right eye.

a)	7.76 -2.00 8.8 select
b)	7.85 -1.50 9.6 select
c)	7.67 -2.50 9.0 select
d)	7.85 -1.50 9.5 select
Go to Discussion Item 4 >>

Spectacle Rx	OD -2.00 -0.75 x 180 OS -2.25 -1.00 x 180
Corneal Measurements	OD 43.50/44.25 @ 90 OS 43.25/44.25 @ 90
Ocular Measurements (OU)
Corneal diameter	11.5mm
Pupil	4.0mm
Fissure width	10.5mm

a) Smaller intrapalpebral fit lenses are suggested if the patient has a wide fissure width and the upper lid rests above the superior limbus. If this is the case and there is no support from the upper lid then the fit between the cornea and the posterior surface of the lens is more critical. This would not be the first choice for this patient. back

Spectacle Rx	OD -2.00 -0.75 x 180 OS -2.25 -1.00 x 180
Corneal Measurements	OD 43.50/44.25 @ 90 OS 43.25/44.25 @ 90
Ocular Measurements (OU)
Corneal diameter	11.5mm
Pupil	4.0mm
Fissure width	10.5mm

b) The patient's upper lid position (upper lid rests below the superior limbus) along with a larger diameter lens that is fit for alignment will aid in achieving a lid attachment relationship, which will work very well in this case. back

Spectacle Rx	OD -2.00 -0.75 x 180 OS -2.25 -1.00 x 180
Corneal Measurements	OD 43.50/44.25 @ 90 OS 43.25/44.25 @ 90
Ocular Measurements (OU)
Corneal diameter	11.5mm
Pupil	4.0mm
Fissure width	10.5mm

c) Smaller intrapalpebral fit lenses are suggested if the patient has a wide fissure width and the upper lid rests above the superior limbus. If this is the case and there is no support from the upper lid then the fit between the cornea and the posterior surface of the lens is more critical. This would not be the first choice for this patient. back

Spectacle Rx	OD -2.00 -0.75 x 180 OS -2.25 -1.00 x 180
Corneal Measurements	OD 43.50/44.25 @ 90 OS 43.25/44.25 @ 90
Ocular Measurements (OU)
Corneal diameter	11.5mm
Pupil	4.0mm
Fissure width	10.5mm

d) The patient's upper lid position (upper lid rests below the superior limbus) along with a larger diameter lens that is fit slightly flat will aid in achieving a lid attachment relationship, which will work very well in this case. The difference between a 9.6mm diameter and a 9.5mm diameter lens is insignificant. Thus, this is also a good initial choice for a diagnostic lens. back

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This page was last updated Thursday, April 24, 2008.

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