Journal of Pediatric Ophthalmology and Strabismus

Posterior Continuous Curvilinear Capsulorhexis With and Without Optic Capture of the Posterior Chamber Intraocular Lens in the Absence of Vitrectomy

Usha K Raina, MD, FRCS, FRCOphth; Vinita Gupta, MS; Ritu Arora, MD; D K Mehta, MS, MNAMS

Abstract

ABSTRACT

Purpose: To evaluate the efficacy of posterior continuous curvilinear capsulorhexis (PCCC) with optic capture of the posterior chamber intraocular lens (PC IOL) in the absence of vitrectomy in preventing secondary opacification of the visual axis following pediatric cataract surgery.

Patients and Methods: Thirty-four eyes of 28 children with congenital or developmental cataract, aged 1.5 to 12 years (mean, 6.39 years), were included in this prospective, randomized study. Anterior continuous curvilinear capsulorhexis (ACCC) with PCCC without optic capture of the PC IOL was performed in group A (18 eyes) and ACCC with PCCC with optic capture of the PC IOL was performed in group B (16 eyes). None of the eyes underwent anterior vitrectomy. Secondary opacification of the visual axis, visual acuity, and possible complications were observed and analyzed.

Results: The follow-up period ranged from 8 to 28 months (mean, 17.5 months). All 16 eyes (100%) in group B had a clear visual axis at the end of followup. Eight eyes (44.4%) in group A had significant opacification of the visual axis. The difference between the two groups was statistically significant (P = .0011). No eye in group B required secondary intervention, whereas all 8 eyes in group A with significant secondary opacification required secondary intervention. There was no statistically significant difference in other complications such as anterior chamber reaction, fibrin formation, lenticular precipitates, and posterior synechiae. The final best-corrected visual acuity at the end of follow-up was comparable in the two groups (P > .05).

Conclusion: PCCC with optic capture of the PC IOL prevents secondary opacification of the visual axis even in the absence of vitrectomy.

J Pediatr Ophthalmol Strabismus 2002;39:278-287.

Abstract

ABSTRACT

Purpose: To evaluate the efficacy of posterior continuous curvilinear capsulorhexis (PCCC) with optic capture of the posterior chamber intraocular lens (PC IOL) in the absence of vitrectomy in preventing secondary opacification of the visual axis following pediatric cataract surgery.

Patients and Methods: Thirty-four eyes of 28 children with congenital or developmental cataract, aged 1.5 to 12 years (mean, 6.39 years), were included in this prospective, randomized study. Anterior continuous curvilinear capsulorhexis (ACCC) with PCCC without optic capture of the PC IOL was performed in group A (18 eyes) and ACCC with PCCC with optic capture of the PC IOL was performed in group B (16 eyes). None of the eyes underwent anterior vitrectomy. Secondary opacification of the visual axis, visual acuity, and possible complications were observed and analyzed.

Results: The follow-up period ranged from 8 to 28 months (mean, 17.5 months). All 16 eyes (100%) in group B had a clear visual axis at the end of followup. Eight eyes (44.4%) in group A had significant opacification of the visual axis. The difference between the two groups was statistically significant (P = .0011). No eye in group B required secondary intervention, whereas all 8 eyes in group A with significant secondary opacification required secondary intervention. There was no statistically significant difference in other complications such as anterior chamber reaction, fibrin formation, lenticular precipitates, and posterior synechiae. The final best-corrected visual acuity at the end of follow-up was comparable in the two groups (P > .05).

Conclusion: PCCC with optic capture of the PC IOL prevents secondary opacification of the visual axis even in the absence of vitrectomy.

J Pediatr Ophthalmol Strabismus 2002;39:278-287.

INTRODUCTION

Secondary cataract formation remains a major complication of cataract surgery and implantation of intraocular lenses m children,1 despite the dramatic advances in surgical techniques and lens designs. The incidence of posterior capsular opacification (PCO) has been reported to vary from 51%2 to 100%.' It is a major obstacle to visual rehabilitation and often defeats die purpose of preventing amblyopia.3,4

Measures to deal with the problem of PCO may be either primary at the time of cataract removal or secondary.5 These include primary posterior capsulotomy with a needle or a vitrectomy instrument, primary posterior continuous curvilinear capsulorhexis (PCCC), pars plana lensectomy, epilemicular lens implantation, secondary pars plana or Hmbal capsulo to my or vi t recto my, and secondary Nd:YAG laser capsulotomy.6 Secondary intervention has the disadvantage of obscuring the visual axis, which can lead to stimulus deprivation amblyopia during the critical period of development. Removal of the center of the posterior capsule alone as a primary procedure is also not enough to prevent PCO in children.7 Lens epithelial cell proliferation with vitreous acting as a scaffold still occurs, resulting in secondary opacification of the visual axis that necessitates a second procedure within months of primary cataract extraction. In developing countries, with travel over long distances and familial circumstances affecting the frequency of follow-up visits, it is often difficult to perform a timely secondary procedure after cataract surgery.

To combat this problem, some surgeons6·8 adopt the approach of combining primary posterior capsulotomy with an anterior vitrectomy to remove the vitreous scaffold and prevent secondary opacification. However, vitreous adhesions and vitreous incarceration in die wound may occur with anterior vitrectomy, increasing the risk of cystoid macular edema9 and retinal detachment.'" The technique of primary PCCC with optic capture as advocated by Gimbel and DeBroff11 has been reported to maintain a clear optical axis even without vitrectomy. It is presumed that this technique prevents the migration of Elschnig pearls into the visual axis because the anterior and posterior capsular leaflets are in direct apposition with each other. This capsular fusion seals the capsular bag and diminishes lens epithelial cell migration, thereby decreasing secondary opacification of the posterior capsular opening." There are few studies available in the literature describing die efficacy of this technique in preventing secondary opacification without vitrectomy. "-13

We undertook a prospective, randomized study of single-stage pediatrie cataract surgery to evaluate and compare the clarity of the visual axis and the visual outcome in eyes diat underwent PCCC with posterior chamber intraocular lens (PC IOL) implantation with and without optic capture in the absence of vitrectomy.

Table

TABLE 1STUDY INCLUSION AND EXCLUSION CRITERIA

TABLE 1

STUDY INCLUSION AND EXCLUSION CRITERIA

PATIENTS AND METHODS

Patients presenting to the pediatrie ophthalmology service of Guru Nanak Eye Centre from December 1997 until July 1999 were recruited to participate in the study. The study protocol was reviewed and approved by the Institutional Review Board. Consecutive patients with developmental or congenital cataract attending the clinic and eligible for primary implantation of a PC IOL, between 1.5 and 12 years old, were eligible for the study. Table 1 presents the inclusion and exclusion criteria.

Written informed consent was obtained from both parents before enrollment in the study. The unit of randomization was the eye. The 34 eyes eligible for the study were prospectively randomized to group A (PCCC without optic capture, n = 18) or group B (PCCC with optic capture, n = 16} by block randomization using a random digit table. In bilateral cases, the eye with poorer vision was enrolled ahead of the fellow eye. The assignment of study patients to the two groups was performed at die time of enrollment.

Preoperative Assessment

Visual assessment was done using standard illuminated vision boxes with Snellen's literate and illiterate (E & C charts) optotypes at 6 m. In eyes for which objective visual assessment was not possible, subjective assessment was done by using objects and toys placed at various distances. Slit-lamp biomicroscopy and photography to study the anterior segment with particular reference to the lenticular details was done in all eyes p reo pera lively. Keratometry, using a Bausch & Lomb lceratometer (Bausch & Lomb Surgical, Inc., St. Louis, MO), was performed in all eyes except two, for which standard for age "K" readings as described by Gordon and Donzis14 were used. In these two cases, keratometry could nor be performed because the children were younger man 2 years and uncooperative for examination. Axial length was measured using ultrasound biometry and IOL power calculated using die SRKII regression formula. All examinations were performed by an independent investigator (VG).

Because a myopic shift has been reported in pediatrie eyes, especially if pseudophakic,15"17 we aimed for a 20% undercorrecnon in patients younger than 2 years and a 10% undercorrection in patients 2 to 4 years old. Children from 4 to 12 years old were prescribed an IOL power emmetropie for their age. Children who were pseudophakic in the fellow eye at the time of surgery were prescribed an IOL power to match the refractive status of the pseudophakic eye.

Surgical Technique

Adequate preoperative pupillary dilatation was achieved using topical cyclopentolate hydrochloride 1% and phenylephrine hydrochloride 10%, supplemented with flurbiprofen sodium (0.03%). All surgeries were performed under general anesthesia by one surgeon (UKR). After a fornix-based conjunctiva! flap was made, a 5.0-mm, partial -thickness, mid-limbal corneoscleral groove was made. A stab incision was made at the 11 -o'clock position and the anterior chamber was deepened using 14 mg/mL of sodium hyaluronare (Healon GV, Pharmacia & Upjohn, Uppsala, Sweden). An anterior continuous curvilinear capsulorhexis (ACCC) of 5.5 to 6.0 mm was performed (as measured over the cornea) using Kraff Utrata forceps after initial puncture of the anterior capsule of the lens with a 26-gauge capsulotomy needle. Hydro dissection was done in every case, followed by irrigation and aspiration of lens matter. Sodium hyaluronate was injected to inflate the capsular bag and a small puncture was made in the posterior capsule with a 26-gauge needle. Sodium hyaluronate was then injected through this to fill the Bergers space and tamponade the vitreous.

A 4- to 4.5-mm PCCC (as measured over the cornea) was performed using Kraff Utrata forceps. The corneoscleral section was enlarged to 5 mm and a PC IOL was then implanted in the capsular bag. Corneoscleral wound closure was done using a 1 0-0 monofilament suture in a continuous shoelace fashion. The anterior chamber was meticulously irrigated at the end of surgery to remove sodium hyaluronate and any debris. No optic capture was performed in group A eyes. In group B, after the wound was sutured, the optic of the PC IOL was captured through PCCC using a Sinskey hook. All IOLs were single-piece polymethylmethacrylate with a 5-mm biconvex optic and 12-mm haptic spread (809 P, Pharmacia & Upjohn). Anterior vitrectomy was not performed in any of the eyes. At the end of surgery, all eyes received a subconjunctival injection of 20 mg of gentamícin sulfate and 2 mg of dexaniethasone sodium phosphate and a subTenon's injection of 20 mg of triamcinolone acetate.

Postoperative Treatment

Postoperatively, all patients received oral steroids (1 to 2 mg/kg of prednisolone acetate) for 2 weeks and topical prednisolone acetate (1%) and ciprofloxacin hydrochloride (0.3%) eye drops tapered during 12 weeks. Mydriatics were used depending on the inflammatory response. The frequency of topical prednisolone eye drops was increased as and when necessary if the eyes showed an increased inflammatory response.

Postoperative Evaluation

All of the patients were examined on the first postoperative day. Repeat evaluations were performed on the fourth day, at 1 week, 2 weeks, 1 month, 3 rnondis, and 6 months, and thereafter every 3 monrlis. All postoperative evaluations were performed by an independent observer (VG). At each visit, visual acuity was recorded and a slit-lamp biomicroscopic evaluation was done for the presence of anterior -chamber reaction, pigment deposits on the IOL, and fibrin in the anterior chamber and che presence and extent of any posterior synechíae. Clarity of the central 4 mm of the posterior capsule was noted at each visit. Lenticular precipitates and PCO were graded as indicated in Table 2. Grading of PCO was modified from Zetterstrom18 to make it more detailed and descriptive. Documentation of significant findings was done by Cari Zeíss photo slit lamp (Carl Zeiss Ophthalmic Instruments Division, Jena, Germany).

Table

TABLE 2GRADING SYSTEM USED FOR LENTICULAR PRECIPITATES AND POSTERIOR CAPSULAR OPACIFICATION

TABLE 2

GRADING SYSTEM USED FOR LENTICULAR PRECIPITATES AND POSTERIOR CAPSULAR OPACIFICATION

Eyes showing evidence on slit-lamp biomicroscopy of visually significant secondary opacification accompanied by a reduction in best- corrected visual acuity underwent Nd:YAG laser or surgical posterior capsulotomy. All eyes underwent refraction at 1 month after surgery and appropriate optical correction was prescribed. Repeat refraction was performed at 3 months and at the end of follow-up and correction was modified if required.

Statistical Analysis

Statistical analysis was performed to quantrfy any differences between the two groups preoperatively and at each postoperative visit using the Student's ? test for quantitative data and the chi-square test or Z test for categoric data. Data were expressed as mean ± standard deviation (SD). Statistical significance was accepted for P values of less than .05.

RESULTS

Patient Demographics

Demographic data of the patients (Table 3) indicate that there was no statistically significant difference in age (t - 0.09; P = .93}, gender chisquare = 0.05; P - -83), or the eye involved (chisquare = 0.15; P = -69) between the two groups. Three children had unilateral and 25 had biiateral cataracts. Both eyes of 6 children were included in the study. The second eye of the remaining 12 children was nor inciuded because they had pseudophakia Jn the fellow eye before the study period. In the remaining 7 children, parents refused surgery in the second eye. Children who were pseudophakic in the fellow eye were prescribed an IOL power to match the refractive status of the other eye. The most common morphologic type of cataract was lamellar in both groups: 1 1 eyes (61.11%) in group A (PCCC with no optic capture) and 13 eyes (81.25%) in group B (PCCC with optic capture) .

Table

TABLE 3PATIENT DEMOGRAPHICS

TABLE 3

PATIENT DEMOGRAPHICS

Tables 4 and 5 contain data on the visual acuity of the two groups. Preoperatively, the average keratometric result was 43.28 ±2.11 D (range, 39 to 45.75 D) in group A and 43.35 ± 1 .90 D (range, 40 to 46.63 D) in group B. The mean axial length was 21.81 ± 1.21 mm (range, 20.07 to 23.95 mm) in group A and 22.67 ± 1.48 mm (range, 20.47 to 25.27 mm) in group B. There was no statistically significant difference between the two groups in these parameters.

Table

TABLE 4CLINICAL DATA OF PATIENTS IN GROUP A (No OPTIC CAPTURE)

TABLE 4

CLINICAL DATA OF PATIENTS IN GROUP A (No OPTIC CAPTURE)

Table

TABLE 5CLINICAL DATA OF PATIENTS IN GROUP B (OPTIC CAPTURE)

TABLE 5

CLINICAL DATA OF PATIENTS IN GROUP B (OPTIC CAPTURE)

Table

TABLE 6COMPARISON OF OCCURRENCE AND SEVERITY OF LENTICULAR PRECIPITATES IN THE Two GROUPS

TABLE 6

COMPARISON OF OCCURRENCE AND SEVERITY OF LENTICULAR PRECIPITATES IN THE Two GROUPS

Table

TABLE 7COMPARISON OF POSTOPERATIVE INFLAMMATION IN THE TWO GROUPS

TABLE 7

COMPARISON OF POSTOPERATIVE INFLAMMATION IN THE TWO GROUPS

Preoperative Complications

The surgery was uneventful in all of the eyes. No vitreous upthrust or iris prolapse was encountered preoperatively because of adequate lowering of intraocular pressure achieved under general anesthesia (by use of intravenous thiopentai sodium prior to performing an ACCC and a PCCC). However, in one eye the ACCC became eccentric.

Inflammatory Complications

Data regarding the occurrence of inflammatory cell deposits or pigment deposits on the IOL surface are given in Table 6. Prevalences of anterior chamber inflammation in terms of the presence or absence of cells, flare, and fibrin are given in Table 7. Posterior synechiae were seen in two eyes each in groups A and B (P = .45) (Fig. 1). There was no statistically significant difference between the two groups in terms of inflammatory complications (P> .05).

Figure 1 . Eye 2 of group B 9 months postopera t i ve Iy showing a clear central visual axis and posterior synechiae with an opacified rhexis margin inferiody.

Figure 1 . Eye 2 of group B 9 months postopera t i ve Iy showing a clear central visual axis and posterior synechiae with an opacified rhexis margin inferiody.

Opacification of the Visual Axis

Table 5 and Figures 2 through 5 show that in group B, all 16 eyes had a clear visual axis until the end of follow-up (range, 8 to 28 months; mean, 17-5 months). In a few eyes, Elschnig pearls were seen extruding from the capsular bag but stopping short at the fusion of the capsular leaflets (Fig. 5). Pearls were not seen behind the optic or in the visual axis of any eye. No secondary intervention was required. A total of 8 eyes (44.4%) in group A (follow-up period: range, 12 to 28 months; mean, 19 months) had secondary opacification of grade 2+ (visually significant) or more (Table 4). The difference in visually significant PCO between the two groups was statistically significant (P = .0011). Occlusion of the visual axis started as early as 2 weeks pos tope rati vely in 1 eye of group A. By 1 month, 3 eyes showed PCO, and at die end of 3 months, a total of 4 eyes had opacification of grade 1+. Opacification progressed with time and by 6 months was visually significant (grade 2+ or more) in 2 eyes. At 1 year of follow-up, a total of 6 eyes had visually significant opacification (grade 2+ or more [Figs. 6 and 7]) and underwent a second intervention (4 had surgical capsulotomy and 2 had Nd:YAG laser capsulotomy). Thereafter, until the iast follow-up, 2 more eyes had to undergo a second intervention to achieve a clear central visual axis.

Figure 2. Eye 3 of group B 1 month postope ral i ve I y showing posterior continuous curvilinear capsulorhexis with optic capture with a clear visual axis.

Figure 2. Eye 3 of group B 1 month postope ral i ve I y showing posterior continuous curvilinear capsulorhexis with optic capture with a clear visual axis.

Figure 4. Eye 1 of group B 27 months postoperative I y with opacification of posterior continuous curvilinear capsulorhexis margins and a clear central visual axis.

Figure 4. Eye 1 of group B 27 months postoperative I y with opacification of posterior continuous curvilinear capsulorhexis margins and a clear central visual axis.

Figure 3. Eye 7 of group B 12 months postopera ti ve I y showing posterior continuous curvilinear capsulorhexis with optic capture with fibrosis of the capsule margins and a clear central visual axis.

Figure 3. Eye 7 of group B 12 months postopera ti ve I y showing posterior continuous curvilinear capsulorhexis with optic capture with fibrosis of the capsule margins and a clear central visual axis.

Figure 5. Eye 2 of group B 1 8 months postopera ti ve I y showing Elschnig pearls interiorly slopping short al the posterior continuous curvilinear capsulorhexis margin.

Figure 5. Eye 2 of group B 1 8 months postopera ti ve I y showing Elschnig pearls interiorly slopping short al the posterior continuous curvilinear capsulorhexis margin.

Visual Outcome

The postoperative improvement in visual acuity was significant in both groups (Tables 4 and 5). Of the 34 eyes in the study, assessment of visual acuity was possible in 31 eyes. Twenty-eight eyes had bestcorrected visual acuity of less than 6/60 before surgery. All showed a significant improvement in visual acuity after surgery. In 8 eyes in group A, there was a decline in best-corrected visual acuity a few months after surgery due to the occurrence of PCO. Of these, visual acuity dropped to less than 6/60 in 3 eyes. After secondary capsulotomy, the visual acuity in these eyes improved. The final visual outcome at the end of follow-up was comparable in the two groups with no statistically significant difference (Fig. 8).

Figure 6. Eye 3 of group A 1 2 months postoperative! y showing opacificaiion of the posterior capsule, grade 3+.

Figure 6. Eye 3 of group A 1 2 months postoperative! y showing opacificaiion of the posterior capsule, grade 3+.

The mean spherical equivalent at the end of 1 month was +0.69 ± 1 .78 D in group A, whereas it was -0.77 ± 1.54 D in group B. At 3 months, the corresponding values were +0.53 ± 1.64 D and -0.49 ± 1 .38 D, which did not indicate any statistically significant difference between the two groups (P= .07). There was no change noted in the mean spherical equivalent on repear refractions performed at the end of follow-up.

DISCUSSION

The most important goal in pediatrie cataract surgery is to provide ideal visual rehabilitation. With the development of vìscoelastics, PC IOLs, and newer surgical techniques, IOL implantation has become an accepted, popular method of aphaktc correction in children. In India, social and climatologie circumstances make the wearing of glasses or contact lenses by children difficult. Familial and economic circumstances also reduce the frequency of follow-up visits normally required for the examination of the cornea and optical adjustments in contact lens wearers, making an IOL the best optical correction of aphakia. However, a major problem m pediatrie IOL implantation is the high incidence of formation of a secondary cataract postope ratively. '

Figure 7. Eye 12 of group A 12 months postopera lively showing opacification of the posterior capsule, grade 2+.

Figure 7. Eye 12 of group A 12 months postopera lively showing opacification of the posterior capsule, grade 2+.

Figure 8. The best-corrected visual acuity was good in the two groups at the end of follow-up.

Figure 8. The best-corrected visual acuity was good in the two groups at the end of follow-up.

The visual axis in children may be obscured not only by proliferation and migration of lens epithelial cells, but also by inflammatory membranes and opacification of the anterior vitreous or hyaloid face.'9 Management of the posterior capsule is essential to a successful visual outcome.

Posterior capsulotomy can be performed at the time of cataract removal (manual PCCC, PCCC with a vitrector, or PCCC with radiofrequency diathermy) or later by Nd:YAG laser3'4·7 or surgery. However, PCCC alone is not enough.7 The dense structure of the young vitreous acts as a scaffold for the growth of cells even in the absence of a posterior capsule, thereby leading to closure of a PCCC, the incidence increasing with time. In their retrospeccive study, Koch and Kohnen20 found that after cataract surgery, children, especially those younger than 6 years, require more than one Nd:YAG laser treatment. They found that all 4 eyes that had PCCC alone required a second intervention. In developing countries in which compliance with follow-up is poor and patients are not available for a timely secondary procedure, one cannot rely on Nd:YAG laser capsulotomy as an intervention to achieve clarity of the visual axis.

To prevent this secondary opacification of the visual axis after a primary posterior capsulotomy, the primary approach can be to either combine it with an anterior vît recto my3·5·8·20 or use Gimbel and DeBroffV technique of optic capture. The disadvantages of PCCC with anterior vitrectomy are vitreous adhesions and vitreous incarceration in the wound, thereby increasing the risk of retinal detachment.10 Other potential complications include IOL dislocation, which has been reported in 3% to 20% of eyes,5'21 and extension of posterior capsular tears, which may occur during anterior vitrectomy. Anterior vitrectomy at the time of cataract surgery also increases die risk of cystoid macular edema,9 although the incidence of cystoid macular edema in children is reported to be low.22

Optic capture of the PC IOL through PCCC establishes a definite barrier between aqueous and vitreous, obviating the need for an anterior vitrectomy. Widi this technique, the anterior and the posterior capsular leaflets fuse anterior to the IOL almost 360° except at the optic-haptic iunctions. This is presumed to lead to the formation of Soemmering's ring anterior to the IOL or to allow release of Elschnig pearls anterior to the IOL from where these are removed by the aqueous. Unlike the vitreous, the aqueous does not provide a scaffold for lens epithelial proliferation. The site at which the haptics enter the capsular bag creates an area in which the posterior capsule is posterior to the optic. This may provide an area in which Elschnig pearls find their way into the posterior chamber. This gap at the optic- haptic junction may be reduced by the choice of IOL design. Gimbel and DeBrofF postulated that using an IOL with a distinct right-angle departure of the haptic from the optic may help in achieving a tighter seal11 than a traditional lens design. They found no opacification of the visual axis in any of the eyes that had optic capture without vitrectomy by using such an IOL.

In contrast, Vasavada and Desais observed opacification of the vitreous face in all 3 eyes that had optic capture without an anterior vitrectomy. In dieir study, the PC IOL used was Slimplant LXlOBD (Alean Laboratories, Fort "Worth, TX), in which the haptic- optic angularion is oblique. Koch and Kohnen20 also used a polymethylmethacrylate IOL diat had an oblique haptic- optic junction. In dieir study, secondary opacification occurred in 4 of the 5 eyes with optic capture without vitrectorny. We used die CeeOn lens (Pharmacia & Upjohn) in this series, which has a distinct right-angle departure of the haptic from the optic (the same haptic-optic angulation used by Gimbel and DeBrofF) to achieve a tighter seal.

In our study, all 16 eyes with optic capture of the PC IOL had a clear central visual axis even in die absence of vitrectomy. Elschnig pearls formed, but stopped short at the fusion of the two capsular leaflets (ie, did not progress behind the posterior capsule) . Another reason for such a cleat visual axis even after 28 months of follow-up may possibly have been the tightness of the seal between the capsular leaflets with optic capture of the IOL. To ensure a good apposition between the IOL and the edges of the posterior capsular opening, the opening should be at least 1 to 1.5 mm smaller than the IOL optic. The mean PCCC size achieved was 4.22 mm (as measured over the cornea) and the mean optic diameter of the IOL used was 5 mm. When the factor of cornea! magnification (1.15) is taken into account,23 the mean PCCC size achieved was 3.67 mm, which was ideal for achieving a tight seal.

Five patients in the study with bilateral cataracts had PCCC with optic capture in one eye and PCCC without optic capture in the fellow eye. In these patients, in whom the influence of disparate preoperative factors was automatically excluded, we found that visual axis clarity and visual outcome were better in the eyes with optic capture, thus emphasizing die role of optic capture in reducing the incidence of PCO. Three of these patients had visually significant opacification of the visual axis in the eye without optic capture, whereas the eye with optic capture had a clear central visual axis. However, after secondary intervention in the eye with opacification, the final visual outcomes were comparable.

Fenton and O'Keefe13 also achieved good clarity of the visual axis in pediatrie cataracts with a low reopacifican on rate by using PCCC without anterior vitrectomy. Of the 32 eyes opetated on in their series, only 5 required Nd:YAG capsulotomy at a mean follow-up of 19 months. In our series, 8 of the 34 eyes required a second intervention. The difference could be because they used a he pari n -coated IOL, which helps in reducing the inflammatory response and may also reduce PCO. However, their study was not prospective and lacked control subjects.

We did not experience the high rate of severe intraocular inflammation reported in earlier señes,24 despite the fact that Indian eyes are more pigmented. A rapid disappearance of IOL cell deposits occurred with time. Posterior synechiae formation of less than 3 clock hours between the capsule and the IOL optic was seen in 4 eyes (11.76%) only. The lower incidence of inflammatory complications in our study could presumably be due to the use of depot steroids at the end of the surgery and the use of systemic steroids in the immediate postoperative period.

The recording of reliable (objective) best-corrected visual acuity (using Snellen's literate and illiterate E & C charts) was possible in 28 eyes postoperatively, whereas subjective assessment (using pictures and objects) was done in 3 eyes. An excellent visual outcome and a totally clear central visual axis were attained in all eyes of group B. In group A, good visual outcome was initially affected by the occurrence of secondary opacification in 8 eyes. We were unabie to obtain visual acuity readings in 3 of the eyes. Even in these cases (2 in group A and 1 in group B), there was considerable improvement in red reflex after surgery, fixation was central, and no deviation was noted. Our study thus emphasizes the efficacy of optic capture of the PC IOL in reducing the incidence of secondary opacification of the visual axis, thereby obviating the need for a second intervention in children older than 1.5 years.

PCCC with optic capture of the IOL is a safe and effective procedure ìn pediatrie cataract surgery and helps prevent PCO even in the absence of vitrectomy. Larger studies with longer follow-up are needed to evaluate its efficacy in the long term. Also, further studies are needed to evaluate is efficacy in children younger than 1.5 years, who tend to have a more reactive vitreous face.

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TABLE 1

STUDY INCLUSION AND EXCLUSION CRITERIA

TABLE 2

GRADING SYSTEM USED FOR LENTICULAR PRECIPITATES AND POSTERIOR CAPSULAR OPACIFICATION

TABLE 3

PATIENT DEMOGRAPHICS

TABLE 4

CLINICAL DATA OF PATIENTS IN GROUP A (No OPTIC CAPTURE)

TABLE 5

CLINICAL DATA OF PATIENTS IN GROUP B (OPTIC CAPTURE)

TABLE 6

COMPARISON OF OCCURRENCE AND SEVERITY OF LENTICULAR PRECIPITATES IN THE Two GROUPS

TABLE 7

COMPARISON OF POSTOPERATIVE INFLAMMATION IN THE TWO GROUPS

10.3928/0191-3913-20020901-08

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