**2.1 Discussion**

In this study, a patient with amblyopia and a monocular posterior polar cataract in the right eye was analyzed. The with-the-rule corneal astigmatism (around 1.4D) was partially corrected by using a steep-axis clear corneal symmetric incision during the operation. Considering the potential influence of the densely opaque and organized tissue in the visual axis of posterior capsule, a posterior capsule continuous circular capsulorhexis was successfully performed during the surgery, and a trifocal IOL was implanted in the capsular bag. However, when the trifocal IOL was implanted as the hydrophilic acrylic IOL was unfolded rapidly, it caused pressure

#### **Figure 3.**

*Pentacam examination performed again at 7 months after surgery shows that the anterior surface corneal astigmatism changed from 1.4 D@93° before surgery to 0.9 D@59° (A, red frame and green frame); Slit-lamp retroillumination imaging showing that the intraocular lens was centered and stable, the dehiscence of the posterior capsular opening at the 8 o' clock position did not change significantly compared to the intraoperative status (B, red arrow); Pentacam tomography showing that the posterior capsule signal at the 8 o' clock position is discontinuous and no contralateral signal is observed, indicating the direction of posterior capsule dehiscence (C, green box and red arrow); Pentacam tomography scan showing that the posterior capsule is incomplete in the direction of nearly the 6 o' clock position; however, the signal of the margin of the posterior capsule is visible and symmetrical (D, green box and yellow arrow).*

**59**

*Special Cases in Cataract Surgery*

basis for this study [2].

to implant a trifocal IOL.

*DOI: http://dx.doi.org/10.5772/intechopen.98260*

on the weak posterior capsule circular capsulorhexis opening, and the dehiscence of posterior capsulorhexis opening occurred. As the posterior capsule and anterior hyaloid membrane were separated with a viscoelastic agent in advance, there was no vitreous overflow. By rotating the position of the IOL, the long axis of the IOL was perpendicular to the direction of the dehiscence of posterior capsulorhexis opening and the four corner loops of the plate-type IOL provided support in the capsular bag, thus ensuring its centering and stability. Although the patient had amblyopia and large astigmatism in the surgical eye, he received full explaination before the operation to ensure his recognition and understanding. The postoperative corneal astigmatism was controlled within 1.0 D, and the far, medium, and near visions were greatly improved compared to those before the operation; the postoperative patient satisfaction was quite high. In 2018, Srinivasaraghavan et al. reported a case of successful implantation of a functional IOL in the capsular bag after a posterior capsule rupture in a traumatic cataract patient, which provided a certain reference

The choice of the trifocal IOL for this case is mainly based on the following considerations: (1) Young patients have a high demand for a full range of vision; (2) Although the patient's cornea had 1.4 D with-the-rule astigmatism, studies have shown that after the production of a symmetric transparent corneal incision on the steep axis of the cornea, a 2.8–3.5 mm clear corneal incision could correct 1.00-2.06 D of astigmatism [3–5]. Based on the surgeon's previous surgical experience, it was considered that astigmatism could be reduced to less than 1.0 D through the symmetric incision on the steep axis of the cornea. Simultaneously, according to the correction analysis of the astigmatism IOL using the Baylor nomogram, it was not necessary to correct with-the-rule astigmatism of less than 1.69 D, which also provided the basis for the implantation of the trifocal IOL in this study [6]; (3) Except for the posterior polar cataract, no organic abnormality was evident in the patient's surgical eye examination. However, through a retrospective analysis of the patient's medical history and various examinations, he was diagnosed as amblyopia, and it was expected that although the postoperative visual acuity could not reach normal, it would be greatly improved compared with the preoperative visual acuity, and the full range of visual acuity could be achieved; therefore, the final choice was

Posterior polar cataract surgery is highly challenging and unpredictable, because the specific conditions of the posterior capsule must always be considered during the operation; only hydrodelineation, without hydrodissection, is performed during the operation, and the anterior chamber must be maintained stable at all times to avoid causing excessive tension on the posterior capsule and thus resulting in posterior capsule rupture [7–9]. Although the posterior capsule of this patient was intact during the operation, its opacity was located in the visual axis, which seriously affected the visual quality after IOL implantation. Therefore, the posterior capsule was subjected to continuous circular capsulorhexis during the operation [9]. When a trifocal IOL was implanted, it was unfolded quickly and caused great tension on the posterior capsulorhexis opening, leading to dehiscence of the posterior capsulorhexis opening. The location of the dehiscence of the posterior capsular was the same as the site where the capsulorhexis crossed over the opacity of the posterior capsule. Considering that the tension resistance of the capsule here was weaker than that of the normal posterior capsule, dehiscence occurred under the state of uneven tension when the IOL was unfolded after implantation. This also suggests that we should try to tear off the opacity part as far as possible during the posterior capsule capsulorhexis to ensure

even and consistent tension resistance of the capsular opening.

After the intraoperative implantation of a trifocal IOL, the dehiscence of posterior capsulorhexis opening occurred beyond our expectation. We must weigh

#### *Special Cases in Cataract Surgery DOI: http://dx.doi.org/10.5772/intechopen.98260*

*Current Cataract Surgical Techniques*

**2.1 Discussion**

The uncorrected visual acuity of the right eye was (far vision 0.4, medium vision 0.4 near vision 0.63) at 1 day after operation, (far vision 0.5, medium vision 0.5, near vision 0.63) at 1 week after operation, and (far vision 0.5,

medium vision 0.5, near vision 0.63) at 42 days after operation, and (far vision 0.5, medium vision 0.5, near vision 0.63), optometry showing −0.75DCX138°, which was corrected to +0.5 at 7 months after operation. At this time, the IOL position was stable and centered as revealed in reexamination (**Figure 3**). There were no manifestations of anisometropia or complaints of obvious glare, halo, and other adverse

In this study, a patient with amblyopia and a monocular posterior polar cataract in the right eye was analyzed. The with-the-rule corneal astigmatism (around 1.4D) was partially corrected by using a steep-axis clear corneal symmetric incision during the operation. Considering the potential influence of the densely opaque and organized tissue in the visual axis of posterior capsule, a posterior capsule continuous circular capsulorhexis was successfully performed during the surgery, and a trifocal IOL was implanted in the capsular bag. However, when the trifocal IOL was implanted as the hydrophilic acrylic IOL was unfolded rapidly, it caused pressure

visual phenomena in the postoperative reexaminations at various stages.

**58**

**Figure 3.**

*and symmetrical (D, green box and yellow arrow).*

*Pentacam examination performed again at 7 months after surgery shows that the anterior surface corneal astigmatism changed from 1.4 D@93° before surgery to 0.9 D@59° (A, red frame and green frame); Slit-lamp retroillumination imaging showing that the intraocular lens was centered and stable, the dehiscence of the posterior capsular opening at the 8 o' clock position did not change significantly compared to the intraoperative status (B, red arrow); Pentacam tomography showing that the posterior capsule signal at the 8 o' clock position is discontinuous and no contralateral signal is observed, indicating the direction of posterior capsule dehiscence (C, green box and red arrow); Pentacam tomography scan showing that the posterior capsule is incomplete in the direction of nearly the 6 o' clock position; however, the signal of the margin of the posterior capsule is visible*  on the weak posterior capsule circular capsulorhexis opening, and the dehiscence of posterior capsulorhexis opening occurred. As the posterior capsule and anterior hyaloid membrane were separated with a viscoelastic agent in advance, there was no vitreous overflow. By rotating the position of the IOL, the long axis of the IOL was perpendicular to the direction of the dehiscence of posterior capsulorhexis opening and the four corner loops of the plate-type IOL provided support in the capsular bag, thus ensuring its centering and stability. Although the patient had amblyopia and large astigmatism in the surgical eye, he received full explaination before the operation to ensure his recognition and understanding. The postoperative corneal astigmatism was controlled within 1.0 D, and the far, medium, and near visions were greatly improved compared to those before the operation; the postoperative patient satisfaction was quite high. In 2018, Srinivasaraghavan et al. reported a case of successful implantation of a functional IOL in the capsular bag after a posterior capsule rupture in a traumatic cataract patient, which provided a certain reference basis for this study [2].

The choice of the trifocal IOL for this case is mainly based on the following considerations: (1) Young patients have a high demand for a full range of vision; (2) Although the patient's cornea had 1.4 D with-the-rule astigmatism, studies have shown that after the production of a symmetric transparent corneal incision on the steep axis of the cornea, a 2.8–3.5 mm clear corneal incision could correct 1.00-2.06 D of astigmatism [3–5]. Based on the surgeon's previous surgical experience, it was considered that astigmatism could be reduced to less than 1.0 D through the symmetric incision on the steep axis of the cornea. Simultaneously, according to the correction analysis of the astigmatism IOL using the Baylor nomogram, it was not necessary to correct with-the-rule astigmatism of less than 1.69 D, which also provided the basis for the implantation of the trifocal IOL in this study [6]; (3) Except for the posterior polar cataract, no organic abnormality was evident in the patient's surgical eye examination. However, through a retrospective analysis of the patient's medical history and various examinations, he was diagnosed as amblyopia, and it was expected that although the postoperative visual acuity could not reach normal, it would be greatly improved compared with the preoperative visual acuity, and the full range of visual acuity could be achieved; therefore, the final choice was to implant a trifocal IOL.

Posterior polar cataract surgery is highly challenging and unpredictable, because the specific conditions of the posterior capsule must always be considered during the operation; only hydrodelineation, without hydrodissection, is performed during the operation, and the anterior chamber must be maintained stable at all times to avoid causing excessive tension on the posterior capsule and thus resulting in posterior capsule rupture [7–9]. Although the posterior capsule of this patient was intact during the operation, its opacity was located in the visual axis, which seriously affected the visual quality after IOL implantation. Therefore, the posterior capsule was subjected to continuous circular capsulorhexis during the operation [9]. When a trifocal IOL was implanted, it was unfolded quickly and caused great tension on the posterior capsulorhexis opening, leading to dehiscence of the posterior capsulorhexis opening. The location of the dehiscence of the posterior capsular was the same as the site where the capsulorhexis crossed over the opacity of the posterior capsule. Considering that the tension resistance of the capsule here was weaker than that of the normal posterior capsule, dehiscence occurred under the state of uneven tension when the IOL was unfolded after implantation. This also suggests that we should try to tear off the opacity part as far as possible during the posterior capsule capsulorhexis to ensure even and consistent tension resistance of the capsular opening.

After the intraoperative implantation of a trifocal IOL, the dehiscence of posterior capsulorhexis opening occurred beyond our expectation. We must weigh the pros and cons according to the specific situation. If the trifocal IOL could not be stably implanted in the capsular bag or if there was a large amount of vitreous overflow, then we would choose to implant a single focal three-piece IOL in the ciliary sulcus, and the optical part was captured in the anterior capsulorhexis opening of less than 6 mm, which could prevent the eccentricity and tilt of the IOL that might occur after surgery and keep its stability [10]. The surgeon assessed that although the posterior capsular capsulorhexis dehiscence occurred during the intraoperative trifocal IOL implantation in this patient, the anterior vitreous membrane was well protected in the early stage and there was no vitreous overflow; therefore, the long axis of trifocal IOL was rotated to the direction perpendicular to the direction of dehiscence, which reduced further pulling of the IOL on the capsulorhexis opening of dehiscence and allowed it to be stable and centered in the capsular bag.

Although this study did not involve a follow-up for 1 year or longer after surgery, the long-term stability of the trifocal IOL remained to be observed; however, this study emphasizes that for posterior capsular continuous circular capsulorhexis in posterior polar cataract surgery or a small range of posterior capsular rupture in common cataract surgery followed by posterior capsular continuous circular capsulorhexis, in circumstances where there is no vitreous overflow, the surgeon can evaluate whether it is feasible to implant the trifocal IOL in the capsular bag according to the actual intraoperative situation and expand the relative indications for trifocal IOL surgery.
