Iris Crystals: A Rare Clinical Finding in Chronic Anterior Uveitis

Abstract

Iris crystals are a rare clinical entity seen in cases of chronic anterior uveitis (CAU). We report one such case with crystal deposition on iris as well as corneal endothelium and anterior lens capsule. No significant change in the crystals was seen over a period of 11 years despite multiple episodes of exacerbation and resolution. Anterior segment optical coherence tomography (AS-OCT) showed crystals as hyperreflective deposits over the corneal endothelium. On confocal microscopy, the crystals were seen as ill-defined hyperreflective lesions on endothelium between 525 and 604 μm. Reduction in the number of crystals was seen after cataract surgery. In conclusion, AS-OCT and confocal microscopy can be used as additional diagnostic tools to analyze iris crystals in CAU.

Introduction

Iris crystals are a rare entity first reported in 1969 in a case of chronic iridocyclitis.[1] Subsequently, case reports of iris crystals in idiopathic chronic anterior uveitis (CAU), Fuch's heterochromic iridocyclitis, sarcoidosis-related CAU, human leukocyte antigen B27-associated CAU, panuveitis associated with pseudolymphoma, and their association with hypergammaglobulinemia were published.[2,3,4,5,6,7,8] We report one such case of a 38-year-old Indian female diagnosed as CAU with crystal deposition on iris as well as corneal endothelium and anterior lens capsule. Clinical features of the patient were documented over a period of 11 years (2006–2017). Morphology of the crystals was analyzed using anterior segment optical coherence tomography (AS-OCT) and confocal microscopy.

Case Report

The patient had presented with complaints of decreased vision, recurrent redness, pain, watering, and photophobia in the left eye for 6 months. Her best-corrected visual acuity was 6/6, N6 OD and 6/12, N9 OS. Intraocular pressure was 16 mmHg OD and 18 mmHg OS with Goldmann applanation tonometry. Right eye examination was normal. Left eye showed circumciliary congestion, large keratic precipitates, and anterior chamber cells 2 + and flare 1+. In addition, few minute shiny crystalline deposits were noted over corneal endothelium [Figure 1a], iris, and anterior lens capsule [Figure 1b]. These bright deposits appeared refractile and glistened with light. Gonioscopy revealed normal open angles in the right eye and peripheral anterior synechiae over about 180° with hyperpigmentation in all quadrants in the left eye. AS-OCT showed crystals as hyperreflective deposits over the corneal endothelium [Figure 1c]. On confocal microscopy, crystals were seen as ill-defined hyperreflective lesions on the corneal endothelium at the depth of 525–604 μm [Figure 1d]. Fundus examination was normal in the right eye. Left eye fundus examination revealed vitreous opacities, membranes, and posterior vitreous detachment which were seen on B-scan as well. Erythrocyte sedimentation rate, C-reactive protein, Mantoux test, blood sugar, serum electrolytes, blood urea, serum creatinine, urine analysis, chest X-ray posteroanterior view, ultrasound abdomen, and serum protein electrophoresis were within normal range. The patient was nonreactive for VDRL, TPHA, HBsAg, HCV, HIV I and II, and RA factor. It was diagnosed as a case of CAU with acute exacerbation. She was managed with topical prednisolone with tapering dose, topical homatropine, and oral diclofenac. The symptoms resolved, but recurred within a month of stopping the medication. Following this, there were multiple recurrences with no clue of exact etiology. Oral prednisolone 40 mg with tapering dosage was subsequently added. Over the period, she developed posterior synechiae, complicated cataract, and secondary glaucoma with persistence of crystalline deposits. Raised intraocular pressure was managed with topical brimonidine, timolol, and dorzolamide. Left eye phacoemulsification and posterior chamber intraocular lens implantation in the bag was done with intracameral dexamethasone at the end of surgery. Routine postoperative medication was advised. Postoperative best-corrected visual acuity was OU: 6/6, N6. Reduction in the number of crystals was noted at follow-up [Figure 2a and b], which was also evident on AS-OCT [Figure 2c] and confocal microscopy [Figure 2d]. The remaining crystals have persisted since then.

Figure 1.

(a) Large keratic precipitates with interspersed crystals over the left eye corneal endothelium; (b) crystals over the iris and anterior lens capsule; (c) anterior segment optical coherence tomography showing keratic precipitates (arrow) and hyperreflective crystals within the keratic precipitates (arrowhead) over the corneal endothelium; (d) confocal microscopy showing altered endothelial morphology with conglomerate keratic precipitates (arrows) and ill-defined hyperreflective crystals (arrowhead)

Figure 2.

(a and b) Clinical photographs, (c) anterior segment optical coherence tomography, and (d) confocal microscopy showing decrease in the number of crystals after left eye cataract surgery

Discussion

Iris crystals are a rare clinical finding in patients with chronic uveitis. They are seen as minute refractile deposits over the iris surface and also on corneal endothelium and anterior lens capsule as seen in this case. They can present in eyes alone, in chronic inflammatory disorders such as chronic uveitis or in combination with systemic crystals in lymphoproliferative disorders or hypergammaglobulinemia.[2,3,4,5,6,7,8] These are thought to be large Russell bodies, precipitates of immunoglobulins in plasma cells.[9] Iris crystals, once formed, do not appear to change in number and position. We followed this case for 11 years and noticed the reduction in the number of crystals following cataract surgery. Intraocular surgery may lead to mechanical disruption or dissolution of the crystals as in this case.

Although their presence does not seem to have any clinical significance, these magnificent jewels do provide a glimpse into the complexities and the brilliance of the eye as an organ.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.