J Korean Ophthalmol Soc.  2011 Oct;52(10):1142-1149. 10.3341/jkos.2011.52.10.1142.

The Short-Term Effect of Limbal Relaxing Incision and Compression Suture on Post-Penetrating Keratoplasty Astigmatism

• Song HB
• Choi HJ
• Kim MK
• Wee WR

• KMID: 2214995
• DOI: http://doi.org/10.3341/jkos.2011.52.10.1142

Abstract

PURPOSE
To investigate the short-term effect of limbal relaxing incisions accompanied by compression sutures on postoperative astigmatism in penetrating keratoplasty.
METHODS
The medical records of patients who underwent penetrating keratoplasty, were followed-up for at least 18 months and had residual astigmatism greater than 4.0 diopters (D), were retrospectively analyzed. The patients had paired limbal relaxing incisions on the steep axis and compression sutures on the flat axis. The paired limbal relaxing incision was done for 2 clock hours each with a depth of 85% of the corneal thickness, and the compression sutures with an average of 3.2 bites were added with a Troutman operating keratometer guide. The visual acuities, corneal astigmatism and complications were evaluated at 1 month and 6 months.
RESULTS
At 1 month after the surgery, the best corrected visual acuities (log MAR) improved from 0.840 to 0.674 (p = 0.037) except for 1 patient with immediate postoperative rejection and another patient with a pre-existing cataract. The mean corneal astigmatism was reduced from 9.118 +/- 3.158 D to 4.982 +/- 3.063 D (p = 0.021). At 6 months after the surgery, the mean corneal astigmatism increased to 5.489 +/- 2.670 D (p = 0.008), and the effect of surgery became statistically insignificant (p = 0.477).
CONCLUSIONS
Paired limbal relaxing incisions and compression sutures were effective short-term on reducing residual corneal astigmatism and improving visual acuities in keratoplasty patients with high astigmatism, but became less effective on corneal astigmatism at 6 months.

Keyword

Astigmatism; Compression suture; Limbal relaxing incision; Penetrating keratoplasty

MeSH Terms

Astigmatism
Axis, Cervical Vertebra
Bites and Stings
Cataract
Corneal Transplantation
Humans
Keratoplasty, Penetrating
Medical Records
Rejection (Psychology)
Retrospective Studies
Sutures
Visual Acuity

Figure

• 

  Figure 1. Preoperative and postoperative photographs and topographs. These figures show typical topographic changes after limbal relaxing incision and compression sutures. The figures on the left are preoperative photographs and topographs with a simulated keratometry of 7.6 diopters. Paired relaxing incisions (arrows) were done at the steep axis on the limbus, and 4 compression sutures (arrow heads) were added at the flat axis on the junction between graft and host. The figures on the right are postoperative photographs and topographs with a simulated keratometry of 2.3 diopters.

• 

  Figure 2. Improvement in BCVA after limbal relaxing incision and compression sutures. Best corrected visual acuities (BCVA, log MAR) improved from 0.840 to 0.674, and got worse in cases of rejection (patient 8, arrow) and cataract progression (patient 9, arrow).

• 

  Figure 3. Mean topographic changes in Kmax, Kmin and topographic astigmatism. At 1 month after the surgery, mean corneal power of steep axis (Kmax) was reduced from 51.3 ± 4.8 D to 49.8 ± 4.1 D (p = 0.075) and mean corneal power of flat axis (Kmin) increased from 42.1 ± 3.1 D to 44.2 ± 5.2 D (p = 0.008). As a result mean corneal astigmatism was reduced from 9.118 ± 3.158 D to 4.982 ± 3.063 D (p = 0.021). At 6 months after the surgery, mean corneal astigmatism increased to 5.489 ± 2.670 D (p = 0.008), and the effect of surgery became statistically insignificant (p = 0.477).

• 

  Figure 4. Vector analysis of mean topographic astigmatism. This polar plot demonstrates the magnitude and the axis of mean topographic astigmatism. Each concentric ring represents 2.0 diopters of change. Vector analysis of mean topographic astigmatism shows changes of 7.9 ± 5.4 diopters. Gray dots (postoperative astigmatism) are closer to the center compared with black dots (preoperative astigmatism).

• 

  Figure 5. Further follow up of corneal astigmatism. Mean topographic astigmatism increases in some patients after the short-term effect of limbal relaxing incision and compression sutures.

Reference

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