Collaborative Case #012: Best Management of a Visually Significant Cataract and a Nasal Pterygium

Although all three surgical scenarios can be considered, the most optimal order would be to perform pterygium surgery first, wait 2 to 3 months, then perform cataract surgery, as it is likely that the astigmatism magnitude and astigmatism axis will change following removal of the pterygium. In some situations, in which the pterygium is mild, cataract surgery can be performed first, and the pterygium can be removed at a later time, if it is bothersome or progresses. Combing pterygium surgery with cataract surgery at the same time is also an option, but the final refractive result can be variable.

In the case presented here, the patient requested that the surgeon do their best to get them to see as well as possible without glasses for distance vision. Additionally, because he had a high deductible, the patient requested that both surgeries (ie, cataract and pterygium) be performed on the same day. The surgeon therefore planned a toric IOL, placed at the 90-degree axis, and pterygium surgery on the same day (Figure 2). The surgeon also recommended limbal relaxing incisions (LRIs) at the 90-degree axis to further reduce the 7.50 D of vertical astigmatism because the toric lens chosen corrected only about 2.00 D of astigmatism.

A few weeks following surgery, the patient reported that his vision was still blurry, and requested a deeper analysis to figure out why his visual outcome was not as good as expected. Topography and refraction were performed, and the topography showed that the axis had flipped following the combination of pterygium surgery and the placement of LRIs.

Preoperatively, the patient had 7.50 D of vertical astigmatism on topography. Following cataract surgery with pterygium surgery and placement of LRIs at the 90˚ axis, the patient now has 3.12 D of astigmatism horizontally. He also has a toric IOL oriented at 90.0 D that corrects 2.00 D of astigmatism. The refraction now has two components: the cornea, which has 3.00 D of horizontal astigmatism, and the toric IOL, which reduces vertical astigmatism and therefore adds to the horizontal astigmatism. The latest refraction revealed about 5.00 D of horizontal astigmatism.

The surgeon recommended a second procedure: rotation of the toric IOL from a vertical position to a horizontal. Because the toric IOL was correcting 2.00 D of astigmatism, the rotation to a horizontal axis (180˚ ) would result in a net reduction of astigmatism by 4.00 D (a toric IOL correcting 2.00 D of astigmatism horizontally would reduce the astigmatism present on the cornea from 3.00 D to 1.00 D. Another option could have been an IOL exchange to an even stronger toric IOL, but at the time of this surgery, stronger toric IOLs were not yet available commercially.

Of note, PRK and LASIK cannot easily correct this level of astigmatism. Additionally, because the patient already had LRIs placed at 90˚, it is not recommended to place additional LRIs at 180˚ in cases of a flipped axis.