CASE PRESENTATION
An 83-year-old woman was referred for elevated IOP
1 month after undergoing repair of a macular hole with
pars plana vitrectomy (PPV) and C3F8 in her left eye. Two
weeks after the PPV, her IOP increased to the low 50s, and
she developed iris bombé and a closed angle. An inferior
laser peripheral iridotomy and medication reduced the
IOP to 30 mm Hg. Two weeks after the peripheral iridotomy,
the angle remained narrow, and the IOP was 38 mm
Hg, despite treatment with bimatoprost and a fixed combination
of timolol and brimonidine as well as oral acetazolamide
500 mg b.i.d. Moreover, the gas bubble allowed
visualization of an inferiorly thinning neuroretinal rim. The
patient was referred for a glaucoma evaluation.
An examination of the patient's left eye found a visual acuity of count fingers, an IOP of 42 mm Hg, a shallow anterior chamber with an open iridotomy inferiorly, and a moderate nuclear sclerotic and cortical cataract. Gonioscopic evaluation revealed a closed angle with peripheral anterior synechiae (PAS) over 280° (except for 80° open to the posterior trabecular meshwork inferiorly). There was 25% gas fill and a glaucomatous optic disc with a thin neuroretinal rim inferiorly and superiorly. The examination of the patient's right eye was significant only for a moderate cataract and narrow angles without PAS.
One week later, the IOP remained 39 mm Hg OS.
DISCUSSION
RNW: Dr. Lin, how would you have approached this
case?
SCL: I would have considered performing ultrasound biomicroscopy (UBM) to help diagnose the causal agent. Certainly, the gas bubble was contributing to the closed angle. Because the gas bubble was diminishing, there could have been a ciliary body effusion causing anterior rotation of the angle. Some of what ophthalmologists have diagnosed as malignant glaucoma in the past has been shown by UBM to be effusions of the ciliary body and forward rotation of the lens-iris diaphragm rather than pushing from expanded vitreous.1,2 A detached ciliary body could occur during vitrectomy or with postoperative inflammation and swelling.
RNW: What would you have done if the UBM had shown a shallow peripheral effusion?
SCL: The conservative medical treatment likely would not change. One would still use topical steroids and prescribe atropine to relax the ciliary body and move the lensiris diaphragm posteriorly. One could also consider draining the effusion. Alternatively, one could perform a vitrectomy for aqueous misdirection.
RNW: Originally, my colleagues and I described two patients in whom the drainage of choroidal fluid was effective, 1 but I have not always had successful results with this approach. As you point out, it is key to differentiate ciliary body detachment from aqueous misdirection, because the management of each is different. In this particular case, what role do you think that the gas is playing?
SCL: Certainly, it is a major contributing factor. Postoperative pressure spikes after the use of intraocular gas are common. A recent study showed that approximately three-quarters of patients with a history of glaucoma and one-half of those without glaucoma developed an IOP spike after PPV.3 Among individuals who have preexisting glaucoma or, as in this case, a narrow angle, the ability to tolerate the elevated IOP and forward rotation of the lensiris diaphragm can be greatly impaired. I think that the vitrectomy and gas bubble likely played a significant role in pushing this patient over the edge.
RNW: If this patient presented to you with a closed angle, would compression gonioscopy have influenced your choice of treatment?
SCL: Three weeks is enough time to develop closed angles with PAS, and I think that this is probably what happened here. In that situation, iridoplasty likely would not open the angle.
RNW: Moreover, the anterior chamber is very shallow, and iridoplasty might not be feasible without burning the cornea. Suppose with compression gonioscopy the angle had opened. What approach would you have employed?
SCL: One possibility would have been to wait until the gas bubble was gone. The size of the bubble was only 25% by the time the patient was referred to you. It is possible that, when the gas bubble completely absorbed, the pressure would have improved and the anterior chamber might have permitted iridoplasty.
CR: Even if the angle had been open to compression, the pressure was 42 mm Hg at presentation, and there was evidence of changes in the optic disc.
RNW: How long could you wait for a gas bubble to dissolve with a pressure of 42 mm Hg when the eye is already demonstrating changes in the optic disc?
SCL: At this point, the physician is backed into a corner. Some clinicians might consider adjunctive glaucoma surgery in addition to taking out the lens. Perhaps a glaucoma drainage device could be implanted or a trabeculectomy performed. With angle-closure glaucoma (ACG), however, extraction of the lens alone may be the best treatment. Two recent articles from Hong Kong randomized patients with ACG (either controlled or uncontrolled) to treatment with phacoemulsification alone or phacotrabeculectomy. The data showed a significant IOP-lowering effect for both procedures, with a small advantage for phacotrabeculectomy in pressure lowering but likely more complications.4,5
RNW: Given that more than 180° of the angle were closed, we thought that removal of the lens alone would not be sufficient. Additionally, we thought that we had an opportunity to open the angle with synechialysis since it had closed relatively recently. In this case, we performed the goniosynechiolysis with gonioscopic visualization.
SCL: I perform goniosynechiolysis with a cyclodialysis spatula or a blunt instrument. I am conservative in my approach. Patients with normal pressures experience approximately a 10% drop with phacoemulsification, and those with open-angle glaucoma achieve a decrease of almost 20%. Patients with pseudoexfoliation and angle closure have even greater IOP lowering. Unpublished data from my colleagues and me from an ongoing prospective study show that the amount of the angle's opening correlates significantly with the amount of IOP lowering after phacoemulsification. Other mechanisms have been suggested to explain the decrease in IOP after phacoemulsification, including the release of prostaglandin; the vibration of the ultrasound itself, which causes changes in the trabecular meshwork6; and cleaning of pigment and debris from the trabecular meshwork by the irrigation.
ASM: Wouldn't knowing the volume of the lens be important to determining how much of an effect phacoemulsification might have on the IOP? Presumably, the lens with higher volume would have a greater pressurelowering effect when removed.
RNW: This is a very good point, and it should be evaluated.
CR: Based on what we have talked about—the possible relationship between the degree of the angle's opening and the degree of IOP lowering—does it not make sense to couple the cataract extraction with goniosynechiolysis in patients who have PAS and closed angles prior to surgery? A 90% success rate for phacoemulsification with goniosynechiolysis in eyes with greater than 180° of PAS and uncontrolled IOP when performed within 6 months of acute angle closure has been reported.7
SCL: As I mentioned, prospective data from Hong Kong showed that phacoemulsification alone in ACG lowers the IOP significantly.4,5
RNW: Our empiric approach to eyes that have cataract and occludable angles without PAS or only minimal PAS is solely to take out the cataract. For eyes in which the angle does not open with compression, there are extensive PAS of 180° or more, and the angle closure has occurred within the past 6 months, we will combine goniosynechiolysis with cataract surgery. If more than 6 months have elapsed, then we perform a trabeculectomy combined with the cataract extraction. Dr. Rodarte, can you provide follow-up on the surgical approach and postoperative course of this patient?
CR: An uncomplicated cataract extraction by phacoemulsificationwith 360º goniosynechiolysis using acyclodialysis spatula was performed. The goniosynechiolysisin the nasal quadrant was performed under gonioscopiccontrol, with opening of the angle and visualizationof the scleral spur confirmed during surgery. Sixweeks postoperatively, the IOP was 16 mm Hg withoutpressure-lowering medications.
CONCLUSION
A patient with medically uncontrolled ACG and 280°of PAS 4 weeks after a PPV underwent cataract extractionby phacoemulsification and goniosynechiolysis. Six weeksafter the procedure, her IOP remained reduced at 16 mmHg from preoperative levels of 40 mm Hg, and her angleremained open.
Section editor Robert N. Weinreb, MD, is a distinguishedprofessor of ophthalmology and directorof the Hamilton Glaucoma Center, Universityof California, San Diego. Dr. Weinreb may bereached at weinreb@eyecenter.ucsd.edu.
Eric H. Leung, MD, MS, and Christopher Rodarte, MD,are senior clinical fellows at the Hamilton GlaucomaCenter, Department of Ophthalmology, University ofCalifornia, San Diego. Dr. Leung may be reached atehleung@glaucoma.ucsd.edu. Dr. Rodarte may be reachedat crodarte@glaucoma.ucsd.edu.
Shan C. Lin, MD, is an associate professor ofclinical ophthalmology, Department ofOphthalmology, University of California, SanFrancisco. Dr. Lin may be reached at (415) 514-0952; lins@vision.ucsf.edu.
Anjali S. Maheshwary, MD, is an ophthalmology residentat the Shiley Eye Center, Department of Ophthalmology,University of California, San Diego. Dr. Maheshwary may bereached at amaheshwary@ucsd.edu.
