Man presents with incidental bilateral sectoral iris abnormalities
Click Here to Manage Email Alerts
A 34-year-old man was referred to the New England Eye Center for incidentally found iris atrophy and corectopia in the right eye, along with cataracts in each eye.
His ocular history included high myopia of –7 D in both eyes for which he wore glasses. His medical history included anxiety and iron deficiency anemia on iron supplementation. He had no known allergies, and his social history was noncontributory.
Source: Omar Abu-Qamar, MD, Lama Hanbali and Astrid Werner, MD
Examination
On examination, visual acuity was 20/20 in both eyes, and IOP was 12 mm Hg in both eyes. Extraocular motility was full and orthophoric, and visual fields were normal by confrontation. Notably, the patient’s right pupil was about 8 mm, was nonreactive and irregular, and peaked at 10 o’clock. His left pupil was 7 mm, oval and nonreactive (Figure 1). He had no relative afferent pupillary defect on either side. He had trace anterior subcapsular cataracts in both eyes. The rest of the anterior segment examination was unremarkable. His dilated exam revealed normal-appearing optic nerves and peripheral lattice degeneration.
Further imaging
Gonioscopy showed angles open to the ciliary body band in both eyes. In the right eye, corresponding iris changes were described as heaped iris with free-floating strands, without obvious corneal touch and without peripheral anterior synechiae (PAS). The left eye also showed heaped iris with no PAS (Figure 2).
Anterior segment OCT (AS-OCT) line scan in the right eye through the sectoral iris changes demonstrated splitting of the iris stroma, with similar changes noted in the left eye (Figure 3).
What is your diagnosis?
See answer below.
Sectoral iris abnormalities
The differential diagnosis for this patient’s presentation was wide and included iridocorneal endothelial (ICE) syndrome, anterior segment dysgenesis (including Axenfeld-Rieger syndrome and iridoschisis), post-inflammatory changes (all causes of chronic iridocyclitis such as herpes simplex virus, varicella-zoster virus, syphilis, etc), and traumatic or post-surgical iris changes.
The differential diagnosis can be narrowed by excluding trauma or eye surgeries, eye infection or inflammation, or high-risk sexual behavior, which were all not relevant given this particular patient’s history. Specular microscopy showed normal endothelial cell density, variability in size and hexagonality, essentially ruling out ICE syndrome. Given the characteristic exam findings and specific AS-OCT changes, a diagnosis of iridoschisis was made.
Discussion
Iridoschisis is defined as separation of the anterior iris stroma from the posterior stroma and muscle layers, with iris strands free floating in the aqueous humor, often described as “shredded wheat.” It is typically a bilateral disease (vs. ICE syndrome, which is 90% unilateral), presents in the sixth to seventh decade of life and has a slight female preponderance. The course is progressive with sectoral iris changes but without iris holes (as seen in ICE syndrome). The cornea is typically spared but can be involved secondary to focal damage by the free-floating iris strands. Glaucoma and cataract formation are the main associated comorbidities. The pathophysiology is unknown. It is a rare entity with fewer than 150 reported cases. The prevalence is likely higher as it is an underreported condition.
Management of iridoschisis is aimed at screening for and managing the comorbidities that can occur, namely glaucoma, which is seen in up to two-thirds of cases. The majority of cases are angle-closure glaucoma, but the mechanism is unknown. Multiple hypotheses have been proposed, including pigment clogging at the level of the trabecular meshwork, trabecular meshwork blocking by the free-floating anterior stromal fibers, pupillary block mechanism by the posterior stromal fibers, and association with plateau iris syndrome. Treatment is similar to treatment for angle-closure glaucoma, with laser peripheral iridotomy performed for the pupillary block component. Fortunately, most cases are responsive to medical therapy alone. Cataract extraction with goniosynechialysis is an option in those with concurrent visually significant cataracts. More invasive interventions such as trabeculectomy are reserved for refractory cases.
Cataract extraction can be complex in iridoschisis cases due to poor dilation and the presence of free-floating iris strands. Strategies for a more successful and safe cataract extraction include using iris hooks, Healon (sodium hyaluronate, Johnson & Johnson Vision) and epi-Shugarcaine, using vitreous cutter and Vannas scissors to amputate the free-floating iris fibers, and applying microcautery to the iris cords.
Clinical course
Glaucoma evaluation for this patient was reassuring with normal OCT retinal nerve fiber layer analysis and ganglion cell complex analysis (Figure 4). The patient will be followed annually to screen for comorbidities, namely glaucoma.
- References:
- Aref AA, et al. Iridoschisis. https://eyewiki.aao.org/Iridoschisis. Updated July 11, 2022.
- BCSC. Ophthalmic pathology and intraocular tumors. Section 4. American Academy of Ophthalmology.
- Doan A, et al. Iridocorneal endothelial syndrome (ICE) – essential iris atrophy: 63-year-old female with PAS, “iris mass”, corectopia, and increased IOP OS. http://www.EyeRounds.org/cases/case14.htm. Published Feb. 21, 2005.
- Edward DP, et al. Pathology of iris atrophy. https://entokey.com/pathology-of-iris-atrophy/#R26-V4-65. Published July 11, 2016.
- McCarey BE, et al. Cornea. 2008;doi:10.1097/ICO.0b013e31815892da.
- Phillips DL, et al. Chandler syndrome: A subtle presentation. http://EyeRounds.org/cases/203-chandlers.htm. Published Feb. 9, 2015.
- Pieklarz B, et al. J Clin Med. 2020;doi:10.3390/jcm9103324.
- Salim S, et al. Iridocorneal endothelial syndrome and secondary glaucoma. https://eyewiki.aao.org/Iridocorneal_Endothelial_Syndrome_and_Secondary_Glaucoma. Updated Aug. 25, 2023.
- For more information:
- Edited by Jonathan T. Caranfa, MD, PharmD, and Angell Shi, MD, of New England Eye Center, Tufts University School of Medicine. They can be reached at jcaranfa@tuftsmedicalcenter.org and ashi@tuftsmedicalcenter.org.
Collapse
Read more about
Click Here to Manage Email Alerts