To compare visual outcomes among eyes that underwent pars plana vitrectomy (PPV) in combination with either anterior chamber intraocular lens implantation (ACIOL) or scleral suturing of posterior chamber lens (PCIOL).
Retrospective comparative case series.
All eyes presented with aphakia or luxated or subluxated posterior chamber intraocular lens (IOL) following complicated cataract surgery, trauma, or spontaneous dislocation. Eyes involving visually significant macular pathology, past retinal detachment, follow-up of less than 6 months, and surgeries requiring the removal of an ACIOL were excluded. The main outcomes measured were final best-corrected visual acuity (BCVA) and surgical complication rates.
Fifty-seven eyes met inclusion criteria; median follow-up was 13.2 months. Initial median BCVA for ACIOL patients was logMAR 1.301 (Snellen equivalent 20/400, range 20/20 to light perception); final median BCVA was logMAR 0.477 (Snellen equivalent 20/60, range 20/20 to light perception, P < .001). Initial median BCVA for PCIOL patients was logMAR 1.239 (Snellen equivalent 20/347, range 20/60 to light perception); final median BCVA was logMAR 0.301 (Snellen equivalent 20/40, range 20/20 to hand motions, P < .001). The change in BCVA between the 2 groups over the course of the study was similar ( P > .05). More epiretinal membrane (ERM) formations occurred postoperatively in the ACIOL group ( P = .011). Other complication rates were similar between both groups.
PPV with secondary IOL placement is safe and effective, resulting in improved visual outcomes regardless of the technique used. Patients undergoing ACIOL placement have a higher incidence of ERM formation.
Secondary implantation of an intraocular lens (IOL) is a complex surgical procedure performed to achieve maximum visual rehabilitation. In the absence of capsular support, the most common anatomic locations to position the lens implant are in the anterior chamber (AC) and with scleral fixation at the surgical sulcus. A number of studies have looked at the pros and cons of anterior chamber intraocular lenses (ACIOLs) vs scleral-sutured posterior chamber intraocular lenses (PCIOLs). Traditionally the most common problems associated with ACIOL implantation include inflammation, cystoid macular edema (CME), glaucoma, and hyphema. Complications associated with scleral-sutured IOLs include lens tilt, suture erosion, and IOL dislocation. Both surgeries have been associated with epiretinal membrane (ERM) formation and retinal detachment (RD).
Secondary implantation of an IOL may be performed in the setting of pars plana vitrectomy (PPV) in those cases where posterior segment pathology needs to be surgically addressed. PPV may be required to rescue a dislocated primarily implanted IOL or to remove pieces of crystalline lens that have fallen into the vitreous cavity, causing inflammation. Surgically, secondary implantation of an IOL is a more complex procedure in the setting of PPV, requiring the use of both vitreoretinal and anterior segment instrumentation.
A number of studies have demonstrated that secondary IOL placement in the anterior chamber or surgical sulcus may be efficacious in the setting of vitrectomy. However, very little literature exists directly comparing visual outcomes between these 2 surgical approaches. The 2 notable studies on the subject come to differing results. One study, albeit focusing on a population suffering from traumatically dislocated crystalline lenses, suggested that postoperative vision is better in those that undergo ACIOL placement. Another study found that final vision was similar in both groups but the mean change in vision was greater for the ACIOL group. We set out to conduct a large retrospective analysis comparing visual outcomes and complication rates in patients undergoing combined pars plana vitrectomy with secondary intraocular lens implantation.
This investigation was conducted with the approval of the Georgetown University Institute review board. A retrospective observational case series was performed of 57 eyes of 57 patients who were referred for retinal consultation with the complication of a subluxed, dislocated, or absent PCIOL after primary cataract surgery or trauma. Searching through a surgical database at a large retina-only subspecialty practice identified patients who might qualify for the study. The following Current Procedural Terminology (CPT) codes associated with lens replacement surgery and vitrectomy were used to identify potential cases; 66985, 66986, 67121, 67120, 66825, 66983, 66984, 66982, 66852, 66920, and 66930. A total of 1124 charts were reviewed for patients who underwent surgery between January 1, 2006 and December 31, 2014. Patients were included if they underwent secondary IOL placement in combination with pars plana vitrectomy. Exclusion criteria included the following: follow-up of less than 6 months, history of retinal detachment, surgeries requiring the removal of an ACIOL, and cases involving a history of visually significant macular pathology.
All relevant data from each patient’s progress notes, surgical records, and ancillary testing were abstracted into a standardized data collection sheet that was used in a structured database program for analysis. Patient data recorded from office charts on initial presentation included the following: patient age, sex, involved eye, lens status (pseudophakic or aphakic), and history of pseudoexfoliation syndrome, glaucoma, diabetes, uveitis, corneal disease, and trauma. The indication for vitrectomy and the cause of primary PCIOL dislocation were also carefully noted, as was presurgical best-corrected visual acuity (BCVA). Details of the surgical procedure were abstracted from the operative report and included the following: surgeon, IOL location, surgical technique, gauge of vitrectomy, and the indication for pars plana vitrectomy. Finally, postoperative findings were recorded, including the following: BCVA at several time points, suprachoroidal hemorrhage, intraocular pressure (IOP) increase above 25 mm Hg, vitreous hemorrhage (VH), retinal detachment (RD), hyphema, ERM formation, persistent corneal edema of duration greater than 1 month, IOL decentration, IOL capture, iatrogenic retinal breaks, persistent inflammation requiring topical corticosteroid use, and all follow-up surgeries.
For all subjects visual acuity measurements were taken using a Snellen chart and were converted to logarithm of the minimal angle of resolution (logMAR) for comparison. For analysis, counting fingers vision at 1 foot was assigned a Snellen equivalent of 20/4000, at 2 feet was 20/2000, and at 3 feet was 20/1333. Hand motions was assigned 20/8000 and light perception 20/16 000.
Medians were used to describe continuous data, as they are more robust against extreme values than means. Fisher exact test was used for comparing categorical variables between 2 groups. Wilcoxon signed rank test and Wilcoxon rank sum test were used for 1-sample and 2-sample comparisons, respectively. Here nonparametric tests were chosen to compare visual acuities, as they are robust to extreme values and need not make the assumption that the data arose from a normal distribution. P < .05 was considered statistically significant.
Fifty-seven eyes of 57 patients who underwent secondary IOL implantation combined with PPV surgery were enrolled in the study. The series included 31 female and 26 male subjects ranging in age from 36 to 92 years, with a median age of 70.5 years. Patients were followed for a median of 13.2 months (range 6–20 months).
All surgeries were performed by 1 of 13 retina surgeons and included vitrectomy followed by implantation of a secondary IOL. Thirty-three patients received an anterior chamber lens (Alcon Laboratories, Inc, Fort Worth, Texas, USA; Model MTA3UO or MTA4UO). Twenty-four patients received a posterior chamber lens sutured to the sclera at the ciliary sulcus (Alcon Laboratories, Inc; Model CZ70BD). Vitrectomy packs used in the surgeries consisted of the following; 20 gauge (n = 8), 23 gauge (n = 19), 25 gauge (n = 29), and 27 gauge (n = 1). In the ACIOL group patients had a mean age of 74 years, with 14 eyes preoperatively aphakic and 19 pseudophakic. In the sutured PCIOL group the average age was 65 years, with 9 eyes being aphakic and 15 pseudophakic preoperatively. The differences in the 2 groups with regard to age and preoperative lens status were not statistically significant ( P > .05).
Pertinent past ocular history for patients in each of the 2 groups was compared. Patients who underwent ACIOL implantation had the following findings: 7 had a history of glaucoma, 1 had a history of uveitis, and 1 had a history of corneal disease. In the sutured PCIOL group the following findings were recorded: 5 patients had a history of glaucoma, 1 had a history of uveitis, and none had a history of corneal disease. There was no statistically significant difference in past ocular history between individuals in the 2 surgical groups ( P > .05).
The indication for secondary lens implantation was recorded. In the ACIOL group 17 eyes presented after complicated cataract surgery, 13 presented after spontaneous IOL dislocation, and 3 presented after traumatic IOL dislocation. In the sutured PCIOL group 12 eyes presented after complicated cataract surgery, 10 presented after spontaneous IOL dislocation, and 2 eyes presented after traumatic IOL dislocation. The differences in the 2 groups with regard to these presenting characteristics were not statistically significant ( P > .05).
Postoperative patient outcomes and complications in the 33 eyes with an ACIOL implant were as follows: 7 had increased IOP within the first month following surgery, 2 had increased IOP following the first month, 0 had RD within 3 months following surgery, 0 had RD after 3 months following surgery, 4 had VH within the first 3 months following surgery, 1 had VH after the first 3 months, 3 had persistent corneal edema extending beyond the first month postoperatively, 0 had IOL decentration within 3 months following surgery, 0 had IOL decentration after 3 months following surgery, 1 had hyphema, 0 had IOL capture, 8 had ERM, 1 had an iatrogenic retinal break, 13 had persistent postoperative inflammation requiring topical steroid use beyond the first month after surgery, and 4 required subsequent surgical intervention.
Postoperative patient outcomes and complications in the 24 eyes with a sutured PCIOL were as follows: 7 had increased IOP within the first month following surgery, 6 had increased IOP following the first month, 1 had RD within 3 months following surgery, 0 had RD after 3 months following surgery, 3 had VH within the first 3 months following surgery, 0 had VH after the first 3 months, 1 had persistent corneal edema extending beyond the first month postoperatively, 0 had IOL decentration within 3 months following surgery, 2 had IOL decentration after 3 months following surgery, 2 had hyphema, 1 had IOL capture, 0 had ERM, 0 had an iatrogenic retinal break, 6 had persistent postoperative inflammation requiring topical steroid use beyond the first month after surgery, and 1 required subsequent surgical intervention.
The only postoperative variable that statistically differed between the 2 groups was the incidence of postoperative ERMs. There was a higher number of ERMs identified postoperatively in ACIOL eyes than in PCIOL eyes ( P = .008). For this variable data were available for 32 out of 33 patients in the ACIOL group. A review of preoperative records indicated that ERMs were not present prior to surgery in those patients who ultimately developed them postoperatively. These data are summarized in the Table .
|Intraocular Lens Location||Anterior Chamber (N = 33)||Posterior Chamber (N = 24)||P Value|
|Increased intraocular pressure (within 1 month postoperatively)||7||7||.544|
|Increased intraocular pressure (after 1 month postoperatively)||2||6||.059|
|Retinal detachment (within 3 months postoperatively)||0||1||.421|
|Retinal detachment (after 3 months postoperatively)||0||0||1|
|Vitreous hemorrhage (within 3 months postoperatively)||4||3||1|
|Vitreous hemorrhage (after 3 months postoperatively)||1||0||1|
|Persistent corneal edema (after 1 month postoperatively)||3||1||.631|
|Intraocular lens decentration (within 3 months postoperatively)||0||0||1|
|Intraocular lens decentration (after 3 months postoperatively)||0||2||.173|
|Intraocular lens capture||0||1||.421|
|Persistent ocular inflammation requiring topical steroids (after 1 month postoperatively)||13||6||.394|
|Follow-up surgery needed||4||1||.385|
In the 4 patients (n = 4 eyes) status post ACIOL who required subsequent surgical intervention, the indications for surgery were as follows: 1 eye required subsequent PPV with IOL removal 6 months post surgery owing to endophthalmitis, 1 eye required mechanical vitrectomy for a vitreous hemorrhage 1 month post surgery, and 2 eyes required PPV with membrane peeling for ERM within 9 months of the original procedure. One of the eyes that underwent membrane peeling had to subsequently undergo a third procedure to remove the ACIOL and perform a trabeculectomy. The 1 patient that required surgical intervention status post sutured PCIOL placement required a PPV with glaucoma tube, endolaser, and a corneal patch graft 9 months status post surgery.
Median BCVA significantly improved in each surgical subgroup between the preoperative and final postoperative visits. In the ACIOL group, median initial BCVA was logMAR 1.301 (Snellen 20/400) and improved to logMAR 0.477 (Snellen 20/60). The estimated median change of visual acuity for the ACIOL group is −1.062 (95% confidence interval: −1.363 to −0.704, P < .001). In the PCIOL group, the median preoperative BCVA was logMAR 1.239 (Snellen 20/347) and improved to logMAR 0.301 (Snellen 20/40). The estimated median change of visual acuity for the PCIOL group is −1.106 (95% CI: −1.474 to −0.801, P < .001). The data do not suggest that the 2 groups differ in visual acuity at preoperative visits ( P = .894), nor do the data suggest a difference between the 2 groups in terms of the amount of change in visual acuity between the 2 visits ( P = .656). Therefore, an analysis that pooled the 2 groups was also performed. It was found that median BCVA in the entire cohort improved from initial presentation at logMAR 1.301 (Snellen 20/400) to final follow-up at logMAR 0.301 (Snellen 20/40); this change is statistically significant ( P < .001). The median follow-up period for the ACIOL group was 13.3 months as compared to 12.4 months for the PCIOL group; this difference is not statistically significant ( P > .05).
Two patients in the ACIOL group ended with worse final than initial visual acuity. One of these patients suffered persistent postoperative inflammation and developed an ERM. The second patient suffered severe persistent corneal edema that did not resolve. One patient in the sulcus-sutured PCIOL group ended with a worse visual outcome. In this case, persistent corneal edema and IOL decentration were documented as the causative factors. This patient also required glaucoma tube placement, with an endolaser and corneal patch graft secondary surgery.