Long-term results of phacoemulsification combined with primary posterior curvilinear capsulorhexis in adults.

OBJECTIVE: To evaluate the 2-year outcomes of phacoemulsification combined with primary posterior curvilinear capsulorhexis (PPCC) in adults.
MATERIALS AND METHODS: In this retrospective case series, 93 eyes of 91 patients with bilateral age-related cataract who underwent phacoemulsification combined with PPCC were evaluated. The study included cases due to postoperative residual posterior capsule opacification despite careful polishing. Data were evaluated on preoperative and postoperative best corrected visual acuity (CDVA) (Snellen acuity), slit-lamp biomicroscopy and intraocular pressure (IOP) measurement. Perioperative and postoperative complications were also recorded.
RESULTS: The mean follow-up was 24.9 ±13.5 months (range, 12-53 months). At the last visit, 87.1% of the eyes had CDVA ≥ 20/40 and 58% had ≥ 20/25. Posterior capsular opacification (PCO) occurred in 2 (2.2%) of patients. No serious complications such as retinal detachment and endophthalmitis were observed during follow-up.
CONCLUSIONS: Cataract surgery combined with PPCC is a safe procedure with a low rate of complications over the long term. This procedure reduced the necessity of Nd:YAG laser capsulotomy in adults with postoperative residual posterior capsule opacification despite careful polishing.

INTRODUCTION

Posterior capsular opacification (PCO) is one of the most common complications of cataract surgery. Patients with PCO have decreased visual acuity, loss of contrast sensitivity, and in some cases, PCO precludes examination of the posterior segment.1 The incidence of PCO is reported to be 20-50% 5 years after cataract surgery in the general population and has been reported to occur in 100% of pediatric patients.23 PCO is characterized by lens epithelial cell (LEC) migration from the equatorial area toward the visual axis. In this process, a posterior capsule acts as a scaffold for LECs.45

Neodymium: YAG (Nd:YAG) laser capsulotomy, is the primary treatment of choice for PCO. However, Nd:YAG laser capsulotomy is associated with retinal detachment, retinal tears, cystoid macular edema, elevation of intraocular pressure, damage to intraocular lens, intraocular inflammation, and macular hole.136

Due to the high incidence of PCO after cataract surgery and the potential complications of Nd:YAG laser capsulotomy, studies for preventing PCO have increased. In these studies, several factors such as different optic material, the edge design of the optic and capsular bending ring implantation have been associated with a low rate of PCO.17

Recently, primary posterior capsulorhexis (PPCC) has been proposed to prevent PCO in adults. The PPCC technique is frequently used in children with or without anterior vitrectomy to prevent posterior capsule opacification (PCO) but is rarely used in adults.8 In PPCC, the central portion of the posterior capsule is removed during cataract surgery to prevent equatorial LEC migration toward the visual axis.9

The aim of the current study was to report the long-term efficacy and safety of phacoemulsification combined with PPCC in adult patients with cataract.

MATERIALS AND METHODS

This retrospective study comprised 93 eyes of 91 patients who underwent phacoemulsification combined with PPCC. The patients were evaluated between September 2005 and September 2009. The study protocol was reviewed and approved by the Institutional Ethics Committee of Beyoglu Eye Education and Research Hospital. Informed consent was obtained from all patients preoperatively.

Only adult patients who underwent cataract surgery and PPCC for age-related cataract were included the study. Patients with a history of glaucoma (n=6), pseudoexfoliation (n=6), uveitis (n=1), zonular weakness (n=1), Vogt-Koyanaga-Harada disease (n=1), and diabetes mellitus (n=9) were also included in this study. Although we do not routinely perform PPCC during cataract surgery on adults, it is performed for cases with residual posterior capsule opacification despite careful polishing. Patients who underwent a posterior capsulorhexis for management of an inadvertent intraoperative posterior capsule tear during cataract surgery were excluded from the study.

Surgical procedure

Three different experienced catarcts surgeons (with 10 or more years’ experience) (A.T.Y., E.B., O.F.Y.) used similar standard phacoemulsification and PPCC techniques. All patients underwent surgery with general (7.5%) or sub-Tenon's anesthesia (92.5%). Topical phenylephrine 2.5% and tropicamid 1% were used for preoperative pupil dilatation. A 3 mm temporal clear corneal incision was created and sodium hyaluronate-chondroitin sulfate (Viscoat®, Alcon Inc., Fort Worth, TX, USA) was injected into the anterior chamber. A 5.0-6.0 mm anterior curvilinear capsulorhexis and coaxial phacoemulsification and irrigation/aspiration (Infinity Vision System, Alcon Inc., Fort Worth, TX, USA) was performed. After the capsular bag was filled with sodium hyaluronate 1% (Healon®; AMO Inc., Abbott Park, Illinois, USA), a flap was created using a 27-gauge needle at the center of the posterior capsule. A small amount of sodium hyaluronate was injected through the capsular opening to separate the underlying anterior hyaloid surface from the posterior capsule. Then, the edge of the incised capsule was grasped with capsule forceps and the incision was extended peripherally to create a well-centered 4-5 mm PPCC opening. A three-piece, sharp-edged hydrophillic-acrylic intraocular lens with a 6 mm optic diameter was implanted in the capsular bag. The sodium hyaluronate-chondroitin sulfate was aspirated from the anterior chamber and the incisions were self-sealing. Postoperatively, patients were instructed to instill topical steroid six times daily and a topical antibiotic five times daily for 1 month.

Demographic data including age, gender, number of eyes, and follow-up time were collected [Table 1]. All patients underwent preoperative and postoperative examinations including measurement of the corrected distance visual acuity (CDVA) with a Snellen chart, slit-lamp biomicroscopy, intraocular pressure (IOP) measurement using applanation tonometry, posterior segment visualization by indirect ophthalmoscopy and ultrasonography when the fundus could not be visualized. Postoperatively, patients were assessed at 1 day, 1 week, 1 month, 3 months, 6 months, 1 year, and a final visit at various times.

Table 1

Patient and study variables

All statistical analyses were performed using SPSS for Windows, Version 16.0 (SPSS, Inc., Chicago, IL, USA). The paired T-test and Chi-square test were used to compare means with statistical significance at P<0.05.

RESULTS

The mean age of the 91 patients was 56.8±16.4 years (range, 19 years to 94 years) [Table 1]. There were 40 (44%) females and 51 (56%) males [Table 1]. Of the 93 eyes, 47 (51%) were right eyes and 46 (49%) were eyes. The mean power of the implanted intraocular lenses was 20.4±4.3 D (range, +3 D to +31 D).

Visual outcomes

The mean preoperative CDVA was 0.26±0.18 (range, 0.1-0.8) (decimal notation). The mean postoperative CDVA at 3 months and at the final visit was 0.75±0.23 (range, 0.05-1.0) and 0.77±0.24 (range, 0.5-1.0) respectively. While there was a significant increase (P<0.001) between postoperative and preoperative CDVA, no significant differences were found between 3 months postoperatively and final visit (P>0.05) [Figure 1]. At the last visit, 87.1% of the eyes had CDVA ≥ 20/40 and 58 % were ≥ 20/25.

Figure 1

Preoperative and postoperative corrected distance visual acuity

Intraocular pressure

The mean preoperative IOP was 15.2±1.5 mmHg. The mean postoperative IOPs at 1 day, 1 week, 1 month, 3 months, 6 months, 1 year, and at last visit were 17.3±1.8 (P=0.067), 14.6±2.2 (P=0.52), 13.7±1.1 (P=0.075), 16.1±1.4 (P=0.30), 15.6±1.6 (P=0.64), 14.2±2.1 (P=0.16), and 15.7±3.1 (P=0.73) respectively. There were no statistically significant differences in IOP before and after surgery (P>0.05, all visits). Preoperatively, six patients were using antiglaucoma medications and at the last visit postoperatively, nine patients were using antiglaucoma medications (P=0.591).

Perioperative and postoperative complications

In one case, a vitreous prolapse occurred after PPCC. An anterior vitrectomy was performed, and intraocular lens was implanted in the bag. PCO impinging on the visual axis that required YAG laser capsulotomy occurred in 2 (2.2%) of 93 eyes [Figure 2]. A visually insignificant IOL decentration only seen on pupil dilation, occurred in one patient (1.1%). At day 1 postoperatively an iris capture was observed in only 2 (2.2%) patients, and they were replaced on the same day. There was no subsequent iris capture for the duration of the follow-up period. Postoperatively, no serious complications, such as endophthalmitis or retinal detachment, were recorded.

Figure 2

Lens epithelial cells proliferation is seen at the contact between the capsular bag and the intraocular lens. The peripheral lateral crescent of the capsular bag that is visible in the picture is completely clear

DISCUSSION

Cataract surgery with combined PPCC is a routine procedure in children with and without anterior vitrectomy to prevent PCO but is rarely used in adults. In this long-term and large case series, we were able to determine the efficacy and safety of phacoemulsification combined with PPCC in adults.

Primary posterior capsulotomy allows a clear visual axis, facilitating visual rehabilitation, and reducing the need for Nd. YAG capsulotomy.10 The problem in PPCC is the potential closure of the PPCC. Tassignon et al.,11 reported total closure in 6 (12%) of 51 eyes. Vock et al.,12 found that the visual axis proliferation was significantly lower in PPCC eyes than in non-PPCC eyes. In our study, the number of patients with PCO was low, at 2 (2.2%), with mean follow-up of 25 months. Nd:YAG laser capsulotomy was performed in these patients [Figure 3]. This low rate of PCO might be associated with a PPCC and the use of a sharp optic edge hydrophilic acrylic intraocular lens which decreased migration of LEC onto the anterior hyaloid surface.

Figure 3

Appearance of clear primary posterior curvilinear capsulorhexis area after Nd:YAG laser capsulotomy

Although postoperative retinal complications such as retinal detachment or cystoid macular edema have been shown to be more common with the breakdown of posterior capsule integrity, the lack of aqueous-vitreous barrier disruption after posterior capsulorhexis has been previously reported.1314 De Groot et al.,14 showed that breakdown of the ocular barrier occurred only in cases of anterior hyaloid rupture. Galand et al.,15 reported retinal complications of primary posterior capsulorhexis as a routine procedure during cataract surgery in adults. In their15 series, 3 of 49 eyes had cystoid macular edema; 3 eyes had vitreous prolapse; and one retinal detachment was noted at postoperative week 4. Lubinski et al.,16 reported that 16% (4/25) eyes had vitreous prolapse to the anterior chamber. In our study, only 1 patient had a vitreous prolapse due to the inadvertent rupture of the anterior hyaloid. In this case, an anterior vitrectomy was performed, and an intraocular lens was successfully implanted in the bag. During the follow-up, no retinal complications such as retinal detachment were observed in this patient.

An intraocular lens decentration can occur after cataract surgery. The causes of decentration include zonular dehiscence, anterior capsule tear, asymmetric capsule contraction, and 1 haptic outside the capsular bag.17 A minimal intraocular lens decentration was observed in only 1 patient in our study. We believe that this decentration was associated with zonular dehiscence caused by pseudoexfoliation rather than PPCC.

Retinal detachment is a complication of cataract surgery especially in cases that lack capsular integrity. In the general population, the rate of retinal detachment following cataract surgery is 0.6-1.7%.18–20 Lubinski et al., reported retinal detachment in only 1 of 25 (4%) patients following cataract surgery with PPCC. However, Nd:YAG laser capsulotomy, which is an alternative procedure to PPCC for preventing PCO, is a potential risk factor for retinal detachment. The incidence of retinal detachment in pseudophakic eyes after YAG capsulotomy has been reported at 1.0-1.9%.2122 Nd:YAG laser capsulotomy results in uncontrolled posterior capsule disruption that induces posterior vitreous detachment and retinal detachment.23–25 In our study, a controlled posterior capsule opening was performed using PCCC without disruption of the anterior hyaloid surface and no retinal detachment was observed at a mean of 25 months follow-up.

We found CDVA was stable from the early postoperative period onward. This outcome was likely due the low rate of PCO and other complications in our study. Additionally, there were no statistically significant differences in mean IOP preoperatively and at all postoperative visits (P>0.05, all cases). Three patients who developed glaucoma postoperatively had pseudoexfoliation. The IOP outcomes of our study are similar to those reported by Stifter et al.,26 who observed no significant differences in IOP between the cataract surgery with combined PPCC and posterior optic buttonholing and conventional cataract surgery.

Cataract surgery with combined PPCC is safe and effective resulting in clinically important advantages such as a low PCO rate, decreased requirement for Nd:YAG laser capsulotomy and long-term prevention of visual morbidity with no adverse effects on intraocular lens stability and IOP.