Management of Cataract in Patients with Irregular Astigmatism with Regular Central Component by Phacoemulsification Combined with Toric Intraocular Lens Implantation

Abstract

Purpose. To evaluate visual acuity (VA) and refractive status in patients with cataract and irregular astigmatism with a regular central component after phacoemulsification with implantation of a toric intraocular lens (IOL). Methods. Patients with cataract associated with irregular astigmatism with a regular central component were enrolled. All patients underwent phacoemulsification and toric IOL implantation. Postoperative visual acuity, residual astigmatism, toric IOL rotation, higher-order aberration, and objective and subjective visual quality were measured 3 months after surgery. Results. Twenty-three eyes were included in the study. The logMAR corrected and uncorrected distance visual acuity values were decreased at 3 months postoperatively (p < 0.005). The preoperative average corneal astigmatism and postoperative residual astigmatism were 1.15–6.97 D (1.99 ± 1.26 D) and 0–2.75 D (0.65 ± 0.57 D), respectively. The average IOL rotation was 3.17 ± 2.01°. Some objective indicators of visual quality, including the modulation transfer function (p < 0.05), Strehl ratio (p < 0.005), 100% VA (p < 0.005), 20% VA (p < 0.005), and 9% VA (p < 0.005), were significantly higher than the corresponding preoperative values. The objective scatter index (p < 0.005) was significantly lower than that before surgery. The postoperative VF-14 scale score was 83.99 ± 14.58. Conclusion. Toric IOL implantation has a good corrective effect on certain specific types of corneal irregular astigmatism with cataract. This effect can be attributed to its ability to correct the regular component of irregular astigmatism. The indications for toric IOL implantation could be expanded to some extent, thereby bringing benefit to more patients.

The Impact of Changes in Corneal Back Surface Astigmatism on the Residual Astigmatic Refractive Error following Routine Uncomplicated Phacoemulsification

“…The incidence of RA >1.00 DC, after implanting toric IOL without considering measured BSA in the calculation of IOL power, is about 20% [ 11 , 12 ]. Gao et al [ 12 ] employed a fixed FCA/BCA ratio constant to further refine their estimates for IOL powers, but this did not nullify the incidence of postoperative refractive surprises. Bandeira et al [ 11 ] used Orbscan II to measure corneal front surface astigmatism.…”

“…Ignoring corneal back surface astigmatism can lead to errors in estimating the surgically induced astigmatism and IOL power selection [1][2][3][4][5][6][7][8][9][10]. Two recent studies found that ocular residual astigmatism >1.00 DC occurred in approximately 20% of eyes at 3 months postoperatively [11,12]. ese two investigations were based on quite different patient groups, toric IOL designs, surgical procedures, and IOL power algorithms.…”

Toric intraocular lenses: Expanding indications and preoperative and surgical considerations to improve outcomes

“…However, sometimes patients with irregular astigmatism (this is an off-label use) also benefit from these lenses. [ 38 39 ] Since these patients often have high astigmatism, use of customized IOLs have resulted in a significant reduction of astigmatism with good outcomes. [ 40 ] Post-penetrating keratoplasty: post-keratoplasty patients often have early cataract formation due to prolonged use of steroids and also have high astigmatism due to irregular healing of the graft host junction.…”

“…However, sometimes patients with irregular astigmatism (this is an off-label use) also benefit from these lenses. [ 38 39 ] Since these patients often have high astigmatism, use of customized IOLs have resulted in a significant reduction of astigmatism with good outcomes. [ 40 ]…”

Spotlight on the Corneal Back Surface Astigmatism: A Review

“…10 In addition, corneal back surface astigmatism is claimed to impact on the performance of the eye in relation to refractive surgery 11,12 and planning for cataract surgery especially in astigmatic eyes. [13][14][15][16][17][18][19][20][21][22][23][24][25] Some investigators reported that corneal back surface astigmatism remains stable after refractive surgery, and this would have a marginal impact on later routine phacoemulsification. [26][27][28][29][30][31][32] This is certainly not the case in patients that underwent more invasive procedures, such as radial keratotomy, where profound changes in corneal back surface astigmatism can occur.…”