Case 1 – Discussion Item 5
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
Corneal Measurements Ocular Measurements (OU) |
OD -2.00 -0.75 x 180 OS -2.25 -1.00 x 180 OD 43.50/44.25 @ 90 OS 43.25/44.25 @ 9011.5mm 4.0mm 10.5mm |
Discussion Item 5: Based on the performance of this fluorescein pattern, what changes would you employ?
a) Larger diameter select
b) Smaller diameter select
c) Steeper base curve select
d) Flatter base curve select
e) No change select
| Spectacle Rx
Corneal Measurements Ocular Measurements (OU) |
OD -2.00 -0.75 x 180 OS -2.25 -1.00 x 180 OD 43.50/44.25 @ 90 OS 43.25/44.25 @ 9011.5mm 4.0mm 10.5mm |
a) A larger diameter will make the lens even steeper based on increased sagittal depth. Note how much fluorescein is pooled centrally, accompanied by excessive mid-peripheral bearing. If a larger diameter were chosen, the base curve would have to be significantly flatter than it presently is, possibly by 1-2 diopters. back
| Spectacle Rx
Corneal Measurements Ocular Measurements (OU) |
OD -2.00 -0.75 x 180 OS -2.25 -1.00 x 180 OD 43.50/44.25 @ 90 OS 43.25/44.25 @ 9011.5mm 4.0mm 10.5mm |
b) A smaller lens would loosen the fit. In this case the lens is already relatively small in comparison to the horizontal iris diameter. Thus, decreasing lens diameter would likely cause intermittent flare and halos as the lens moves with the blink. Smaller is not the best choice here. back
| Spectacle Rx
Corneal Measurements Ocular Measurements (OU) |
OD -2.00 -0.75 x 180 OS -2.25 -1.00 x 180 OD 43.50/44.25 @ 90 OS 43.25/44.25 @ 9011.5mm 4.0mm 10.5mm |
c) A steeper base curve would create more fluorescein pooling and potentially cause physiological problems relating to decreased tear exchange underneath the lens. back
| Spectacle Rx
Corneal Measurements Ocular Measurements (OU) |
OD -2.00 -0.75 x 180 OS -2.25 -1.00 x 180 OD 43.50/44.25 @ 90 OS 43.25/44.25 @ 9011.5mm 4.0mm 10.5mm |
d) Flattening the base curve is the desirable change in this case. Tip: If making changes by altering base curve, alter at least 0.50D (0.10mm) for a significant impact. back
| Spectacle Rx
Corneal Measurements Ocular Measurements (OU) |
OD -2.00 -0.75 x 180 OS -2.25 -1.00 x 180 OD 43.50/44.25 @ 90 OS 43.25/44.25 @ 9011.5mm 4.0mm 10.5mm |
e) While the patient initially may think this lens is comfortable because it doesn’t move, wearing it long term could cause corneal health problems because of the lack of tear exchange. back