Abstract
Purpose
To describe a novel technique for cataract surgery in patients with iris coloboma.
Methods
The technique involves 1) creation of an inferiorly displaced capsulorrhexis and 2) amputation of one intraocular lens (IOL) haptic, thus allowing for controlled IOL decentration in the direction of an inferior iris defect.
Results
We report favorable outcomes in two eyes (one patient) where eccentric capsulorrhexis and haptic amputation were employed during one-piece IOL repositioning in one eye and cataract surgery with three-piece IOL implantation in the contralateral eye.
Conclusion
In coloboma patients who are asymptomatic from their iris defect and do not have a cosmetic desire for repair, eccentric capsulorrhexis and IOL haptic amputation is a viable surgical option that allows for the preservation of a clear visual axis without the need for iris repair.
Introduction
Globe coloboma describes the spectrum of iris, lens, ciliary body, zonule, choroid, retina, and optic nerve defects that can arise due to failed closure of the embryonic fissure. 1 Notably, cataracts arise earlier in colobomatous eyes compared to non-colobomatous eyes. 2 Importantly, underlying coloboma can complicate cataract surgery due to associated microphthalmos, poor pupillary dilation, and zonular instability.3,4 In those with iris coloboma, risk of complications (including hyphema, iritis, and iris dialysis) further increases when iris repair—typically by means of pupilloplasty or artificial iris implantation—is pursued at the time of cataract surgery.5,6
Nevertheless, despite its risks, concurrent iris repair is often necessary at the time of cataract surgery.5,6 Traditionally, cataract surgery involves creation of a centric capsulorrhexis with subsequent placement of the intraocular lens (IOL) at the center of the capsular bag. This results in the need for iris repair in patients with defects that extend beyond the edge of the IOL in order to exclude interfaces that can ultimately contribute to visual aberrations, including 1) the aphakic space peripheral to the IOL, 2) the margin of the capsulorrhexis, 3) the proximal portion of the IOL haptic, and 4) the edge of the IOL optic. 7 Moreover, concurrent iris repair may also improve cosmesis and reduce glare, diplopia, and light sensitivity in those who are symptomatic from their coloboma. 5
Yet, many patients with iris coloboma are asymptomatic from their iris defect and may not have a cosmetic desire for iris repair. 5 This brings into question whether iris repair at the time of cataract surgery is necessary in this population, especially if a clear visual axis can be achieved through alternative techniques not requiring iris manipulation. Herein, we report two cases (two eyes in one patient) that highlight a novel technique employing 1) an inferiorly displaced capsulorrhexis with 2) subsequent amputation of one IOL haptic allowing for controlled decentration of the IOL in the direction of an inferior iris defect. Together, this novel technique allows for a clear visual axis without the need to address the colobomatous pupil in iris coloboma.
Case presentations (Cases 1 and 2)
A 53-year-old woman with a history of congenital coloboma OU (with known iris, retina, and optic nerve involvement) was referred to our service for intermittent glare and positive dysphotopsias OD following cataract extraction with implantation of a one-piece, monofocal, posterior chamber IOL ten months prior. Pupilloplasty was reportedly attempted at the time of her cataract surgery but could not be performed. Additional ocular history included strabismus surgery OD during childhood and amblyopia OD. Her medical history was otherwise unremarkable. Notably, the patient reported no history of photophobia, monocular diplopia, glare, or other visual aberrations during childhood or young adulthood.
On examination, BCVA was counting fingers (CF) at her face OD and 20/30 OS. IOP was 18 mmHg OD and 19 mmHg OS. Undilated and dilated slit-lamp examination OD were both notable for an inferior iris defect with visualization of the inferior margin of the capsulorrhexis, proximal IOL haptic, edge of the IOL optic, and peripheral aphakic space through the colobomatous pupil (Figure 1A, 1C and 1E). Trace posterior capsule wrinkles and peripheral posterior capsule opacification were also visualized. Dilated fundus examination OD was notable for a large coloboma extending inferonasally from the optic disc and involving the macula. Undilated and dilated slit-lamp examinations OS both revealed an inferior iris defect and 2+ nuclear sclerosis cataract (Figure 2A, 2C and 2E). Dilated fundus examination OS was notable for a large coloboma extending inferonasally from the optic disc and involving the macula. Optical biometry (IOL Master, Zeiss, Oberkochen, Germany) was notable for small white-to-white corneal diameters of 10.7 mm OD and 10.6 mm OS.
A-F.
A-F.
Given her symptoms, the patient underwent inferior repositioning of her IOL OD two days after presentation. 1.5 months after presentation, she underwent dropless cataract phacoemulsification and posterior chamber IOL implantation (with inferior displacement) OS for progressive blurred vision.
Methods/surgical technique
OD (Case 1)
Surgical approach OD is demonstrated in Supplemental Video 1. A peribulbar block was administered, and paracentesis was made. Viscoat ophthalmic viscosurgical device (OVD) (Alcon, Geneva, Switzerland) was then injected to fill the anterior chamber and coat the endothelium. A 2.4 mm keratome blade was used to create a triplanar self-sealing clear corneal main incision.
A Sinskey hook and Provisc cohesive OVD (Alcon) were used to separate the anterior capsule from the IOL. The one-piece IOL was then removed from the capsular bag and brought into the anterior chamber. Irrigation and aspiration (Alcon Centurion) were then used to remove residual cortical material from the posterior capsule. One of the haptics from the one-piece IOL was then prolapsed through the main incision and amputated using MicroSurgical Technologies (MST) scissors (Redmond, Washington, USA). The IOL was then placed back into the capsular bag with the site of the amputated haptic directed inferiorly toward the iris defect. Next, MST scissors and Utrata capsulorrhexis forceps were used to extend the original capsulorrhexis inferiorly to account for the colobomatous pupil.
Residual OVD was removed using irrigation and aspiration. A small amount of vitreous was noted in the anterior chamber extending from around the capsular bag at the site of the coloboma; anterior vitrectomy was performed. Intracameral Miochol-E (acetylcholine chloride ophthalmic solution) (Bausch & Lomb, Laval, Canada) was administered to induce pupillary constriction. The IOL optic was subsequently noted to be well-centered inferiorly in accordance with her colobomatous pupil. The corneal incisions were then hydrated with balanced salt solution (BSS). Postoperatively, she was placed on a topical prednisolone drop (gtt) taper and topical moxifloxacin gtt.
OS (Case 2)
Surgical approach OS is demonstrated in Supplemental Video 2. A paracentesis was made, followed by injection of epi-Shugarcaine (epinephrine 0.025% and lidocaine 0.75% in fortified BSS). Viscoat OVD was then injected to fill the anterior chamber and coat the endothelium. A 2.4 mm keratome blade was used to create a triplanar self-sealing clear corneal main incision.
A cystotome needle and Utrata capsulorrhexis forceps were used to create an anterior continuous curvilinear capsulorrhexis that was decentered inferiorly to accommodate her inferior iris defect. BSS on a blunt-tipped cannula was used for hydrodissection and hydrodelineation. Using the phacoemulsification unit (Alcon Centurion), the nucleus was then removed. Irrigation and aspiration were then used to remove residual cortical material. The capsular bag was then infused with cohesive OVD, and the main incision was enlarged to accommodate the IOL B-cartridge. The leading haptic of the AR40e three-piece IOL (Johnson and Johnson Vision, Irvine, California, USA) was then placed in the capsular bag, and the trailing haptic was left outside the main incision. The optic and trailing haptic were each grasped and separated. Using a Sinskey hook, the IOL was rotated with the site of the amputated haptic directed inferiorly toward the iris defect. The residual OVD was removed using irrigation and aspiration. The IOL optic was positioned and subsequently noted to be well-centered inferiorly in accordance with her colobomatous pupil. The corneal incisions were then hydrated with BSS. Intracameral and intrastromal moxifloxacin were administered. A subconjunctival injection of triamcinolone was then administered at the conclusion of the case.
Results
OD (Case 1)
The patient's postoperative course was uneventful OD. At the 1.5-month postoperative visit, the patient reported resolution of her presenting symptoms OD. On examination, BCVA was CF at 1ft OD, and IOP was 19 mmHg. On slit-lamp examination, the capsulorrhexis and amputated IOL were noted to be well centered inferiorly in accordance with her colobomatous pupil (Figure 1B, 1D and 1F). At the 7-month postoperative visit, the patient reported stable vision. On examination, BCVA was CF at 3ft OD, and IOP was 18 mmHg. On slit-lamp examination, the capsulorrhexis and amputated IOL were again noted to be well centered inferiorly in accordance with her colobomatous pupil.
OS (Case 2)
The patient's postoperative course was uneventful OS. At the 1-week postoperative visit, the patient reported subjective improvement in her visual acuity OS. On examination, BCVA was 20/20 OS, and IOP was 14 mmHg. On-slit lamp examination, the capsulorrhexis and IOL were noted to be well centered inferiorly in accordance with her iris defect (Figure 2B, 2D and 2F).
At the 1-month postoperative visit, the patient reported occasional glare and intermittent blurry vision at distance OS. On examination, BCVA was 20/20 OS, and IOP was 13 mmHg. On-slit lamp examination, the capsulorrhexis and IOL were noted to be well centered inferiorly in accordance with her iris defect without evidence of pseudophacodenesis. At the 2-month postoperative visit, the patient reported satisfaction with her vision OS, with significant improvement in her glare symptoms and resolution of her intermittent blurry vision. Examination was unchanged. At the 6-month postoperative visit, the patient reported stable vision OS. On examination, BCVA was 20/20 OS, and IOP was 19 mmHg. On-slit lamp examination, the capsulorrhexis and IOL were again noted to be well centered inferiorly in accordance with her iris defect without evidence of pseudophacodenesis.
Discussion/conclusions
Congenital iris coloboma does not usually result in significant visual issues and, thus, does not typically necessitate repair.5,7 Nevertheless, during cataract surgery, replacement of the crystalline lens with an IOL of a smaller diameter placed at the center of the capsular bag results in the creation of new interfaces and spaces that can produce visual aberrations unless the colobomatous pupil is corrected. 7 Although iris repair offers several additional potential benefits, including improved cosmesis and possible reduction of glare, diplopia, and light sensitivity in patients symptomatic from their coloboma, manipulation of the iris is not without risk.5,6 Risk of complications related to iris repair—including hyphema, iris dialysis, and iritis—is further magnified by other anomalous anatomy often seen in colobomatous eyes (e.g., microphthalmos).1,5,6
Thus, it may be desirable to circumvent iris manipulation in cases without cosmetic or therapeutic reasons for repair, especially if a clear visual axis can be achieved through alternative techniques. Herein, we report a novel approach employing 1) an inferiorly displaced capsulorrhexis and 2) subsequent amputation of one of two IOL haptics, thus allowing for controlled decentration of the IOL in the direction of an inferior iris defect. Together, this novel technique allows for a clear visual axis without the need to correct the colobomatous pupil.
The technique's feasibility is aided by the fact that coloboma most often affects the inferior or inferonasal portion of involved ocular structures. 1 Thus, gravity can be leveraged to maintain the amputated IOL in its proper, inferiorly displaced position. Moreover, the amputated IOL retains one haptic, which further serves to stabilize the IOL. The three-piece IOL used in Case 2 (AR40e, Johnson & Johnson Vision) has a length (haptic-to-haptic) of 13 mm, which decreases to 9.5 mm with amputation of one haptic. This is slightly less than the mean diameter of the capsular bag in normal eyes after cataract extraction. 8 Nevertheless, patients with coloboma often have smaller eyes, 1 as is the case in the patient described here; thus, in patients with smaller capsular bags, the remaining haptic is able to reach the capsular equator superiorly, helping to stabilize the IOL. Over subsequent months, the capsular bag shrinks and remodels around the amputated IOL, offering further stabilization. 8 Nevertheless, larger capsular bags may present an issue if the remaining haptic is unable to reach the capsular equator superiorly.
Although haptic amputation is feasible in one-piece IOLs, as demonstrated in Case 1, haptic-optic separation in these situations requires cutting at the junction. This, in turn, can produce an irregular edge which may, at least theoretically, increase risk of complications, including capsular tears and Uveitis-Glaucoma-Hyphema (UGH) Syndrome. 9 Ideally, a three-piece IOL should be used with this technique since separation at the haptic-optic junction can be achieved via relatively gentle pulling. 10 Also with the aim of maximizing safety, we recommend employing low phacoemulsification fluidic settings (e.g., an infusion IOP of 40 mmHg and aspiration flow rate of 30 cc/min, as used by our group) when performing our cataract surgery approach.
This technique does have several limitations. Firstly, patients who are symptomatic from their iris defect or have a desire for improved cosmesis may be better served by other approaches. Additionally, given the importance of gravity in helping to direct and maintain the IOL in an inferiorly displaced position, the technique is best applied in cases with relatively midline, inferior iris defects—thus reducing the likelihood of the edge of the IOL optic falling within the visual axis and potentially contributing to postoperative dysphotopsias. Moreover, given the absence of one haptic, IOLs may be more prone to dislocation and pseudophacodenesis, especially in the early postoperative period; nevertheless, the risk of these complications should gradually decline in the months following surgery as the eye continues to heal and capsular bag shrinks around the artificial lens. 8
Another point to consider is that once the eye is dilated intraoperatively, it may be challenging to gauge if the size and location of the eccentric capsulorrhexis appropriately accounts for the colobomatous pupil; if misgauged, the edge of the eccentric capsulorrhexis may lie within the visual axis and thus potentially contribute to postoperative dysphotopsias. Moreover, this eccentric capsulorrhexis is likely to extend closer to the capsular equator, thus presenting an increased risk for posterior capsular tears and vitreous loss. Even for the experienced cataract surgeon, we recommend careful consideration of the aforementioned factors along with rigorous patient selection and counseling prior to employment of this technique. Lastly, our study is limited by its relatively short follow-up, precluding longer-term assessment of visual outcomes, IOL stability, postoperative complications, and patient satisfaction.
With the exception of colobomatous eyes with relatively small iris defects, omission of iris repair is typically not possible after cataract surgery with a centric capsulorrhexis and IOL. Our technique avoids the need for iris repair by adjusting the centration of key steps in cataract surgery. Together, this may allow for more efficient and safe cataract surgery in patients with iris coloboma.
Footnotes
Acknowledgments
We would like to thank the patient for granting written permission to publish this information.
Contributorship statement
The following contributions were made by the listed authors. JJF and RP helped in planning, data collection, revision of data, and preparation of the manuscript.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Ethics statement
Institutional Review Board (IRB) approval was deemed not required following consultation with the Massachusetts Eye and Ear IRB.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
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References
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