Case of Iris Atrophy in Patient with Sickle Cell Disease

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Iris Atrophy in Sickle Cell Disease
Via NEJM

Iris atrophy in a patient with sickle cell disease

This article describes the case of a 56-year-old male patient with sickle cell disease diagnosed with iris atrophy. The patient presented to the ophthalmology clinic for a routine eye examination. His medical history was significant for sickle cell retinopathy which was treated with laser photocoagulation. The patient, however, was asymptomatic at the current presentation. On examination, the patient’s visual acuity was 20/20 in both eyes. The examination further showed mild nuclear sclerosis of the lens with extensive iris atrophy in the anterior segments of both eyes. Both eyes also showed fibrotic retinal neovascularization.

The findings are consistent with treated and regressed retinopathy. Sickle cell disease can manifest with ocular complications, especially in patients with the HbSC genotype. Patients with the HbSC genotype are more susceptible to ocular complications compared to those with other genotypes. Iris atrophy is commonly associated with vaso-occlusion with infarction. Similarly, in this case, the findings are associated with proliferative sickle cell retinopathy in the same eye. The patient was called back for a follow-up after 6 months and remained asymptomatic.

Iris atrophy

Iris atrophy is a rare and progressive disorder of the eye which presents with a pupil that is out of place or there are distorted areas of degeneration or holes on the iris. The condition slowly progresses over time and generally affects only one eye. In several cases, it may further lead to secondary glaucoma and vision loss because of a subsequent closure of the drainage angle. Essential iris atrophy is a subtype of iridocorneal endothelial (ICE) syndromes, a unique ophthalmic disorder that can cause various degrees of corneal oedema, secondary angle closure glaucoma and iris atrophy. While the syndromes may vary, all the disorders affect the eye, and some symptoms may overlap. This may make it difficult to distinguish between them.

If the iris atrophy is of unknown origin, it is often secondary to the vaso-occlusive process of sickle cell disease. The prevalence is found to be higher in males with sickle cell disease. Iris atrophy is closely related to proliferative sickle retinopathy in the same eye.

Signs and symptoms

The most common symptoms of essential iris atrophy include a displaced or distorted pupil. Other signs may include patchy areas of degeneration on the iris or even holes in the iris. The edge of the pupil may turn outward in some cases. The onset of the disease is generally gradual and the changes in the shape and the pupil are noticed before any changes to the vision. Interestingly, it may take over several years for the holes in the iris to develop.

In some cases, iris atrophy may present with the attachment of portions of the iris to the cornea, swelling of the cornea or corneal oedema, and abnormalities in the corneal endothelium (cells lining the cornea). These changes cause glaucoma, which is an increase in the pressure in the eye and vision loss.

Causes

Essential iris atrophy and endothelial syndromes are thought to be caused by the same mechanism. However, the cause of the syndromes is not exactly known. It is believed that the defect is caused by a cellular membrane secreted by abnormal endothelial cells. This membrane covers the iris and drainage angle of the eye. The contraction of the membrane triggers pupillary changes and angle closure glaucoma. Other studies have shown that chronic inflammation may cause the disease. Furthermore, ICE syndromes may also be caused by in-vitro herpes infection localised in the endothelial layer. Based on this theory, if one eye is infected, the second eye develops immunity before it can be infected. While the prevalence of ICE syndromes is not yet known, it is a rare disorder that most commonly affects females in the middle adult years, contrary to this case.

References

  1. Di Meglio, L. and Scott, A., 2022. Iris Atrophy in Sickle Cell Disease. New England Journal of Medicine386(17), pp.1646-1646.

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Dr. Aiman Shahab is a dentist with a bachelor’s degree from Dow University of Health Sciences. She is an experienced freelance writer with a demonstrated history of working in the health industry. Skilled in general dentistry, she is currently working as an associate dentist at a private dental clinic in Karachi, freelance content writer and as a part time science instructor with Little Medical School. She has also been an ambassador for PDC in the past from the year 2016 – 2018, and her responsibilities included acting as a representative and volunteer for PDC with an intention to make the dental community of Pakistan more connected and to work for benefiting the underprivileged. When she’s not working, you’ll either find her reading or aimlessly walking around for the sake of exploring. Her future plans include getting a master’s degree in maxillofacial and oral surgery, settled in a metropolitan city of North America.

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