Cataract and vitreoretinal disease can coexist in the elderly population. After vitrectomy, 75% eyes develop significant cataract within one year and 95% within two years, requiring subsequent cataract surgery.1 Thus, phakic eyes requiring vitreoretinal surgery may merit concurrent cataract removal, in order to improve surgical visualization of the retina and to avoid the need for cataract extraction soon after vitreoretinal surgery, thereby avoiding a second procedure to facilitate early visual rehabilitation. Combining phacoemulsification and posterior chamber intraocular lens (PCIOL) implantation with parsplana vitrectomy (PPV) in eyes with significant cataract and coexisting vitreoretinal pathology is becoming increasingly common.2345678910 No such study is reported from the Indian subcontinent.2345678910 The aim of the study was to review and analyze our experience in a large series of combined cases at a tertiary care eye hospital in India.
Materials and Methods
The medical records of consecutive patients who underwent combined phacoemulsification with PCIOL implantation and PPV from January 2000 through December 2004 were retrospectively reviewed. Only those patients who had clinically significant cataract prior to the surgery with a minimum follow-up of six months were included in the study. Cataracts were considered significant if they hampered the surgical visualization of the retina and those that were dense enough to require cataract extraction within the next one year.
All patients had a complete preoperative and postoperative assessment including visual acuity testing, slit-lamp biomicroscopy, intraocular pressure (IOP) measurement and indirect ophthalmoscopy. Ultrasonography was performed to assess posterior segment status when the fundus could not be visualized. The intraocular lens (IOL) power was calculated using the SRK II formula. The other eye was used to calculate the IOL power when fundus pathology precluded the accurate measurements. Postoperative examinations were at one week, four weeks, three months and finally at six months. The postoperative acuity was considered to be the best corrected visual acuity (BCVA) at six months postoperative examination. The outcome measures recorded were the anatomical success of retina, defined as the completely attached retina, intraoperative and postoperative complications and the final BCVA.
Peribulbar or general anesthesia (children) was used and phacoemulsification was performed prior to PPV. Endocapsular phacoemulsification technique (clear corneal incision) was performed, comprising 5.0 to 5.5 mm continuous curvilinear capsulorrhexis, phacoemulsification and irrigation and aspiration (I/A) of the cortex. Posterior capsule polishing was done to remove the posterior capsular cells. Foldable hydrophobic acrylic lenses were implanted in the capsular bag. The viscoelastic material was thoroughly evacuated from the anterior chamber (AC) to prevent an immediate postoperative IOP rise. The incision was closed with a single 10-0 nylon suture before the vitrectomy. The AC maintainer was used for stabilization in eyes which were oil-filled and had undergone a previous PPV. The AC maintainer was placed inferiorly through the corneal paracentesis. A standard 3-port PPV11 was performed using a 20-gauge vitreous cutter and an endoilluminator. Sclerotomies were placed 3.5 mm posterior to the limbus. Wide-field fundus visualization system (Biom 3, insight instruments) was used in all cases. Various vitreoretinal procedures performed included peeling of the posterior hyaloid membrane, epiretinal membrane peeling, photocoagulation, cryotherapy, fluid-gas exchange and gas or silicone oil injection in appropriate cases.
A total of 65 eyes of 64 patients (out of total of 92 patients) fulfilled the study criteria. The mean age of the patients was 50.9 years ± 17.1 (range, five to 82 years). There were 21 (32.9%) females and 43 (67.1%) males. The follow-up ranged from six to 26 months. Twenty-four patients (37.5%) were known diabetics and 22 patients (34.3%) were known hypertensives. Thirteen eyes (20%) had undergone previous vitrectomy with silicon oil injection. The indications for vitreoretinal surgery are summarized in Table 1. Vitreous hemorrhage with or without retinal detachment (19 eyes, 29.2%) was the most common indication for the vitreoretinal procedure.
The indications for cataract surgery included visually significant cataract that precluded adequate visualization necessary for the vitreoretinal procedure or those that were dense enough to require cataract extraction within the next one year. The details of preoperative cataract are summarized in Table 2. Posterior subcapsular cataract with or without associated nuclear sclerosis (34 eyes, 52.3%) was the most common type of cataract. Nuclear sclerosis was judged and defined at the slit lamp. Grade I was early nuclear sclerosis with mild yellow color of the posterior lens in the slit beam. Grade II was yellow color change throughout the lens. Grade III was yellow brown coloration throughout the lens and Grade IV was a brown-colored lens.
Four eyes had preoperative posterior synechiae, which were broken during phacoemulsification. Viscomydriasis was achieved successfully in three of these eyes and in the fourth eye, four nylon iris hooks were used to manage the nondilating pupil. All the cases had uneventful phacoemulsification except one in which capsular tension ring had to be used for four clock hours of zonular dialysis detected during the surgery. In the bag foldable hydrophobic acrylic lens was placed in all the cases. The AC maintainer was used in 13 eyes (20%) which had previous vitrectomy and were oil filled, to ensure the stability of the AC during the surgery. Medical-grade silicone oil of 1000 centistokes viscosity was used in 21 eyes (32.3%) for tamponade. Intraocular perfluoro propane (C3 F8) gas was used in 34 eyes (52.3%) and air was injected in seven eyes (1.1%). Silicone oil removal was done after a minimum of 12 weeks. At the time of silicon oil removal, center of the posterior capsule was removed with a vitreous cutter to prevent posterior capsule opacification. Retinal detachment did not recur in any eye after silicon oil removal.
Primary anatomical success of retina was achieved in 59 eyes (90.7%) after combined phacoemulsification and vitreoretinal surgery. Six eyes had a re-detachment which was detected at four weeks follow-up. Two eyes with recurrent retinal detachment underwent repeat surgery. However, anatomical success of retina could not be achieved in one of these and finally became phthisical. Four of these patients refused to undergo any further surgery. Details of the postoperative complications are enumerated in Table 3. As can be seen, complications seen were similar between the two subgroups of those who had undergone previous vitrectomy compared to those who were undergoing primary vitrectomy, except for the postoperative inflammation which was significantly more in the previous vitrectomy group (42%) (P=0.014, Fisher exact test).
Postoperatively, visual acuity improved in 48 eyes (73.8%), was unchanged in 12 eyes (18.5%) and deteriorated in five eyes (7.7%). Of the five patients whose visual acuity deteriorated postoperatively, four eyes had a re-detachment, for which patients refused to undergo any further surgery and in one patient after the repeat surgery the eye gradually became phthisical. Visual acuity outcomes are summarized in Table 4.
Cataract often coexists with vitreoretinal pathology and can preclude a successful cataract surgery outcome as the presence of cataract hampers posterior segment visualization during vitreoretinal surgery. If the surgery is done sequentially, the patient runs the risk of losing vision due to cataract despite a successful vitreoretinal intervention.12 The patient would then be forced to undergo two separate episodes of vision loss and two separate evaluations and interventions with attendant costs, risks and recoveries. In these cases, a combined surgery probably is the procedure of choice to treat cataract and vitreoretinal pathology.2345678910 The primary benefit is the facilitation in fundus visualization and avoidance of second surgery and other benefits are secondary. Progressive postvitrectomy cataract can also hamper the surveillance of the postsurgery vitreoretinal condition. However, there are possible disadvantages of the combined procedures such as difficulty in visualizing the capsulorrhexis, cataract wound dehiscence caused by globe manipulation during subsequent vitreous surgery, intraoperative miosis after cataract extraction, bleeding from anterior structures and loss of corneal transparency from corneal edema and descemet's folds.1314
Cataract surgery by phacoemulsification was performed before the vitrectomy in this series. It is possible that small incision phacoemulsification surgery with foldable IOLs allow better retinal visualization after cataract extraction than older techniques. Use of wide-field systems and procedures such as use of iris retractors, aspiration of blood and pigment from the AC optimized the view of the posterior ocular structures. An important consideration in cases of combined surgery is the timing of IOL implantation. Some surgeons have suggested that IOL implantation should be delayed until the vitrectomy is completed, as this maintains a small self-sealing incision and avoids light reflexes and the prismatic effects from the lens that might complicate visualization of the posterior pole, especially the most peripheral retina.1516 However, we had implanted PCIOL in all our cases prior to the vitrectomy. It enables the stretching and visualization of the posterior capsule, which reduces the risk of unintentional damage to the capsule with the vitreous cutter. Secondly, IOL implantation is easier in the presence of vitreous support than after vitrectomy. Thirdly, the IOL stabilizes the iris-capsule diaphragm preventing posterior capsule bulge, when endo-tamponades are used. We did not encounter any vitrectomy-induced IOL dislocation or pupillary capture during the surgical procedure.
Another aspect of combined surgeries is the type of the incision and the IOL to be used. Silicone oil tends to condense on silicone IOLs, therefore, silicone IOLs must be avoided in combined operations. Instead, a polymethylmethacrylate (PMMA) or acrylic polymer IOL should be used.17 Corneal tunnel with hydrophobic acrylic IOLs were used in all our cases. Heiligenhaus et al.9 reported that both clear corneal and scleral incisions were safe in the combined surgery, however, clear corneal incisions with foldable IOLs may be associated with less postoperative inflammation and posterior capsule opacification. In our study corneal tunnel incision was found to be safe and was not associated with any additional difficulties or complications. Wound leakage, IOL decentration or capsule contraction was not seen in any of our cases.
A subgroup of our patients (20%) had a previous failed vitreoretinal surgery done elsewhere. Difficulties involved in cataract surgery in patients who had previously undergone PPV have been described.121819 Extremely deep AC during phacoemulsification, zonular dehiscence, increased mobility of the posterior capsule and loss of nuclear fragments posteriorly have been reported. Sneed et al.19 reported difficulty in performing cataract extraction after vitrectomy due to insufficient vitreous support. Recently Cheung et al. have described a simple maneuver for AC stabilization and safer phacoemulsification, by placement of the second instrument between the iris and the anterior capsule.20 We resorted to the use of AC maintainers for such cases and had no additional complications during the surgery.
Scharwey et al.21 described 38 eyes, all of which underwent clear corneal phacoemulsification and vitrectomy with IOL placement at the end of the procedure. The authors commented that both visual outcome and complications were dependent upon the underlying vitreoretinal pathology and were not related to the combined procedure technique. Visual results in our study are very much what we would expect from a series of vitreoretinal procedures of this nature. Visual acuity improved in 48 eyes (74%). In the cases where vision decreased, it was judged to be on the basis of the vitreoretinal condition.
A few postoperative complications, specifically AC fibrin exudation and posterior capsular opacification were related to the combined procedure and would not have occurred in cases of vitrectomy alone. However, as expected, greater AC reaction was noticed in cases which had undergone previous vitrectomy.
Opacification of the posterior capsule has previously been mentioned as a frequent postoperative anterior segment complication in eyes with combined surgery.21 We did not find a high rate of PCO in our series, six of 65 eyes (9%) needed subsequent treatment for the same. However, at the time of subsequent silicone oil removal, the center of the posterior capsule was removed with a vitreous cutter to prevent PCO.
Our experience with combined surgery is encouraging and by proper patient selection, a faster visual rehabilitation can be provided and multiple surgeries can be avoided. We also acknowledge that the present study is limited by its retrospective nature and heterogenecity in diagnosis.
Source of Support:
Aditya Jyot Research Foundation, Mumbai, India.
Conflict of Interest:
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