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Combination technique used for zonular dehiscence with dislocated cataract
A surgeon wanted to control chronic angle closure glaucoma that was induced by zonular dehiscence and a partially dislocated cataract.
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Secondary angle closure glaucoma due to zonular dehiscence associated with anterior dislocation of a cataractous lens can be problematic both to the patient and the cataract surgeon. Aqueous outflow obstruction due to this shift in the lens position leads to increased IOP that can cause eye pain and often requires immediate ophthalmic care.
Although medical management using anti-glaucoma medications can temporarily decrease IOP, a more permanent solution is warranted to alleviate the patient’s symptoms and improve vision. Such surgical intervention can be somewhat challenging. The surgical plan should aim at restoration of a normal anterior chamber angle that allows adequate egress of the aqueous humor, preventing any significant stress to the remaining zonules intraoperatively using a safe surgical technique for removal of the cataract. Such a surgical plan would help minimize any potential complications, including lens drop to the posterior segment during cataract surgery.
In this column, Dr. Chen describes his technique of managing such a case of anterior cataractous lens dislocation due to zonular dehiscence that resulted in increased IOP and a painful eye.
Thomas John, MD
OSN Surgical Maneuvers Editor
A 62-year-old Chinese man from Beijing with a history of blurred vision in his right eye for a period of 1.5 years was examined in my office. Clinical examination of the right eye revealed two peripheral iridotomies, a shallow anterior chamber and a cataract (Figure 1).
Figure 1. Clinical examination of the right eye revealed two peripheral iridotomies, a shallow anterior chamber and a cataract.
Images: Chen M
Figure 2. Additional UBM was performed on July 3, 2012, and a diagnosis of a right cataract that was partially dislocated anteriorly, a shallow anterior chamber and broken zonules was made.
Figure 3. UBM showed normal anatomy in the left eye.
He was initially examined at a local hospital in Beijing, where his vision did not improve with refraction, and he then visited a Beijing military hospital, where an ultrasound biomicroscopy (UBM) was done on June 1, 2012. He was referred to the Tong Ren Eye Hospital of Beijing Capital Medical University. Additional UBM was performed on July 3, 2012, and a diagnosis of a right cataract that was partially dislocated anteriorly, a shallow anterior chamber and broken zonules was made (Figure 2). UBM showed normal anatomy in the left eye (Figure 3).
The right anterior chamber depth was 1.89 mm (Figure 4), while the left eye had an anterior chamber depth of 3.29 mm (Figure 5). The corrected vision was 20/80 with –4.25 +1.50 × 76 in the right eye and 20/30 with +0.5 sphere in the left eye. IOP was 45 mm Hg in the right eye and 17 mm Hg in the left eye.
The patient was treated with Lumigan (bimatoprost, Allergan) every day, Combigan (brimonidine tartrate 0.2%/timolol maleate 0.5%, Allergan) twice daily and Diamox (acetazolamide, Duramed) 250 mg by mouth twice daily to maintain normal IOP in the right eye of about 18 mm Hg. The anterior chamber depth in the right eye improved after a laser peripheral iridotomy at the 6 o’clock position. While in Beijing, he was also recommended to undergo cataract surgery in his right eye. He visited Honolulu, where a local ophthalmologist performed a second peripheral iridotomy at the 8 o’clock position (Figure 1).
On Nov. 9, 2012, the patient experienced pain and pressure over his right eye and he was treated at the Queens Hospital, Honolulu. I examined him subsequently in my office and confirmed the need for cataract surgery with endoscopic cyclophotocoagulation (ECP) in the right eye to improve vision and control chronic angle closure glaucoma. Due to the zonular dehiscence shown on the UBM and a partially dislocated cataract, he underwent surgery in his right eye on Nov. 29, 2012, with the LenSx femtosecond laser (Alcon) to minimize further damage to the zonules and soften the cataract for supranuclear phacoemulsification (phaco outside the bag), a laser limbal relaxing incision to correct astigmatism, implantation of a larger capsular tension ring, and ECP (Figure 6). Postoperatively, the uncorrected vision in the right eye was 20/20, with a normal IOP of 17 mm Hg without any glaucoma medication. The anterior chamber was deep, and the posterior chamber IOL was well- centered in the capsular bag (Figure 7).
Figure 4. The right anterior chamber depth was 1.89 mm.
Figure 5. The left eye anterior chamber depth was 3.29 mm.
Figure 6. LenSx 5.25-mm central round capsulorrhexis.
Figure 7. Postoperative view of the right eye showing a deep anterior chamber, round pupil and well-centered posterior chamber IOL.
Discussion
Causes of lens dislocation include pseudoexfoliation syndrome, trauma, Marfan syndrome, retinitis pigmentosa, homocystinuria, uveitis, old age and zonulopathy. Some lenses that are partially anteriorly dislocated can cause angle closure glaucoma. UBM is a great tool to detect the absence of zonules, as shown in this case. The LenSx laser can perform a perfect capsulorrhexis and prevent zonular damage (Figure 6).
The laser-assisted lens fragmentation using the LenSx can reduce phacoemulsification energy and is suitable for a supranucleus technique. The supranuclear phacoemulsification technique, which is performed outside the capsular bag, for the most part helps avoid further damage to the zonules. The larger capsular tension ring can stabilize the capsule bag, which is jeopardized by the broken zonules. ECP, which utilizes laser treatment to the ciliary body intraocularly after phacoemulsification but before IOL implantation and wound closure, can reduce the secretion of aqueous humor and lower IOP. ECP was indicated in this case because most of the trabeculum may have been already damaged from chronic angle closure glaucoma where laser trabeculoplasty may not be successful. Therefore, surgery with the LenSx laser, limbal relaxing incisions, supranuclear phacoemulsification, capsular tension ring implantation and ECP were beneficial for this patient.
Routine phacoemulsification that does not protect the zonules and capsule tends to have complications such as vitreous loss. Thus, the incidence of cystoid macula edema will increase along with having uncontrolled glaucoma. Here, I present this combined technique that can minimize complications and obtain the best visual results with glaucoma control, as evident in this patient.
Conclusion
Modern ophthalmic imaging devices, such as UBM, can provide clear imaging that helps make a more accurate clinical diagnosis for weak zonules. Ophthalmic surgeons can then establish surgical plans to avoid potential intraocular complications during surgery. Modern ophthalmic therapeutic devices, such as laser-assisted cataract surgery, capsular tension rings and ECP, can be utilized for the best outcomes.