The development of secondary glaucoma following congenital cataract removal is a significant postoperative complication. Aphakic glaucoma is the second most common cause of pediatric glaucoma after congenital glaucoma and the most common long-term complication of pediatric cataract surgery. The diagnosis and treatment of these patients can be difficult, with many patients remaining completely asymptomatic despite increased intraocular pressure (IOP).
Aphakic glaucoma can be classified based on gonioscopic findings and time of onset. Reports have demonstrated a bimodal time of onset with both early and late onset.1 Late-onset aphakic glaucoma is associated with an open angle, whereas early-onset aphakic glaucoma is typically seen in patients with the closed-angle type.1,2 Of the two, the late-onset open-angle type is the most common form of glaucoma in aphakic patients following cataract surgery.
We present an uncommon example of early-onset closed-angle glaucoma following lensectomy for congenital cataract.
On July 3, 2018, a 17-month-old girl was referred from an outside ophthalmologist for evaluation of elevated IOP and suspected aphakic glaucoma of the left eye. The patient was born with a congenital cataract in the left eye that was removed elsewhere on March 31, 2017, but had no other significant medical history. Initial examination showed corneal haze presumed to be secondary to corneal edema with IOP of 26 mm Hg by Perkins applanation tonometry with a central corneal thickness of 760 µm. The patient received dorzol-amide hydrochloride/timolol maleate twice per day, latanoprost at bedtime, and acetazolamide 25 mg/kg/day divided into four doses per day. At the 10-day follow-up visit, the IOP was 40 mm Hg by Perkins applanation tonometry in the setting of poor medication compliance by the mother's report. Four days later, IOP decreased to 15 mm Hg by Perkins applanation tonometry with compliance with the medication regimen.
As the cornea cleared, the decision was made to perform an examination under anesthesia to evaluate the cause of the patient's elevated IOP and to perform appropriate surgery as indicated by the findings. During the examination under anesthesia performed on July 25, 2018, it was determined there was complete occlusion of the pupil by vitreous prolapsing through the pupil (Figure 1) verified by intraoperative ultrasound biomicroscopy (Figure 2).
Microscopic view during examination under anesthesia shows a vitreous plug herniating through the pupil into the anterior chamber. (Image provided courtesy of Camilo Martinez, COA, Children's National Medical Center.)
Ultrasound biomicroscopy of the left eye was performed and demonstrated bowing of the iris plane with a large plug of vitreous extruding through the pupil into the anterior chamber. (Image provided courtesy of Camilo Martinez, COA, Children's National Medical Center.)
A generous anterior vitrectomy was performed to remove the prolapsed vitreous from the anterior chamber and peripupillary margin, where it was strongly adherent to the anterior surface of the iris as seen in Figure 3 (the white circumferential line just peripheral to the pupil edge). A peripheral iridectomy was then performed via the vitrector handpiece. One month after surgery, the patient's IOP was within normal limits with no glaucoma medications.
Microscopic surgical video screen capture taken in the immediate postoperative period. Note the fibrotic white irregular border just outside of the pupil on the surface of the iris where the adherent vitreous plug was removed. (Image provided courtesy of Camilo Martinez, COA, Children's National Medical Center.)
In this case, the patient presented with new-onset unilateral aphakic glaucoma 7 months after the removal of a congenital cataract and was found to have vitreous pupillary block with iris bombe on examination. Many hypotheses have attempted to explain the etiology of aphakic glaucoma, but no clear consensus has been identified. One theory holds that removal of the lens in the developing eye may alter the normal development of the filtration angle, leading to decreased aqueous outflow and increased IOP. Others attribute elevated IOP to pupillary block from a postoperative inflammatory reaction to residual lens material with the formation of synechiae in the angle and pupillary edge. Three retrospective studies evaluating the etiology of aphakic glaucoma1–3 were analyzed, reporting that 16.5% of aphakic glaucoma cases were secondary to pupillary block/angle-closure and 83.5% were the open-angle type (n = 85).
A literature search performed at the time of this report found only one other reported case of vitreous pupillary block with iris bombe as a diagnosed etiology of closed-angle aphakic glaucoma in a child. In this case, Zhu et al4 described a 9-month-old female infant who presented with increased IOP 6 months following bilateral cataract removal. The patient was taken to the operating room for examination under anesthesia and possible trabeculectomy, where ultrasound biomicroscopy showed pupillary obstruction by vitreous herniation and angle closure. Our case report findings and response to vitrectomy were similar to those of Zhu et al.
In the 1940s to 1960s, when intracapsular cataract extraction was common, it was not unusual to see these patients decades later with large mushroom-shaped vitreous plugs prolapsed through the pupil into the anterior chamber. Despite the then universal practice of creating a peripheral iridectomy at the time of intracapsular cataract extraction, many of these patients would go on to develop glaucoma from pupillary block and iris bombe.
These forms of aphakic glaucoma have become rare today as a result of our current surgical methods and improved understanding of other risk factors. In 2005, a retrospective cohort study1 compared patients with simple aspiration lensectomy versus lensectomy and anterior vitrectomy with the outcome of pupillary block and secondary glaucoma. The group without anterior vitrectomy showed a statistically significant increased incidence of pupillary block compared to the group with combined anterior vitrectomy at the time of lensectomy. This article helps demonstrate the risk of fibrosis and reclosure of the vitreous face leading to secondary glaucoma in patients without adequate anterior vitrectomy at the time of lensectomy.
Other methods used to reduce the risk of secondary glaucoma include intracameral injections of acetylcholine or triamcinolone to determine whether vitreous is in the anterior segment. Despite the minimal risk of these medications, however, a normally executed anterior vitrectomy should be sufficient to mitigate their use. Likewise, a peripheral iridectomy can be an additional safeguard to prevent this complication, but it also is not without risk of complications. However, pupillary block in these patients can be avoided if an adequate anterior vitrectomy is performed, with the additional benefit of preventing a cyclitic membrane on the face of an intact vitreous postoperatively. Our case emphasizes the need to perform an appropriate anterior vitrectomy at the time of lensectomy in children because peripheral iridectomies are rarely performed or needed when an adequate vitrectomy has been done.
- Koc F, Kargi S, Biglan AW, Chu CT, Davis JS. The aetiology in paediatric aphakic glaucoma. Eye (Lond). 2006;20:1360–1365. doi:10.1038/sj.eye.6702150 [CrossRef]
- Freedman SF, Lynn MJ, Beck AD, Bothun ED, Örge FH, Lambert SR. Glaucoma-related adverse events in the first 5 years after unilateral cataract removal in the Infant Aphakia Treatment Study. JAMA Ophthalmol. 2015;133(8):907–914. doi:10.1001/jamaophthalmol.2015.1329 [CrossRef]
- Ma CX, Lu Y, Lü J, Yang L, Tan FL, Li BB. Clinical analysis of aphakic glaucoma after congenital cataract in infants [article in Chinese]. Zhonghua Yi Xue Za Zhi. 2016;96(27):2176–2178. doi:10.3760/Cma.j.issn.0376-2491.2016.27.014 [CrossRef]
- Zhu XJ, Zhang KK, He WW, Sun XH, Meng FR, Lu Y. Diagnosis of pupillary block glaucoma after removal of congenital cataracts with intraoperative ultrasound biomicroscopy: a case report. BMC Ophthalmol. 2016;16(1):58. doi:10.1186/s12886-016-0238-9 [CrossRef]