🗒️

Cataract in systemic disease

Summary
Diabetes mellitus
Pathophysiology
Cataract features
Myotonic dystrophy
Cataract features
Atopic dermatitis
Cataract features
Neurofibromatosis type 2
Cataract features
Radiology in Focus
Ultrasound biomicroscopy (UBM)
Optical Coherence Tomography (OCT)
B-scan Ultrasound
References
Author(s)

Summary

Cataract has been associated with several systemic diseases, importantly diabetes mellitus, myotonic dystrophy, atopic dermatitis and neurofibromatosis type 2. Many of these cataracts have unique, characteristic patterns.

Summarised below are the salient learning points regarding cataracts associated with systemic disease.

Diabetes mellitus

Pathophysiology

Hyperglycaemia results in a high glucose level in the aqueous humour, which diffuses into the lens
Glycosylation of lens proteins causes over-dehydration
Vacuoles of cortical fluid develop, which opacity over time

Cataract features

‘Snowflake’ pattern - appear as grey-white subcapsular opacities. These cataracts can grow rapidly with the entire lens turning white. These are rare and typically occur in the young
Age-related cataracts develop at a younger age in diabetes mellitus

Image showing bilateral posterior subcapsular ‘snowflake’ cataracts in a diabetic patient. Image courtesy of Park.

Myotonic dystrophy

Cataract features

‘Christmas tree’ pattern - bilateral iridescent needle-shaped cortical opacities. 90% of patients with myotonic dystrophy develop these in their 30’s.
These grow over time into wedge-shaped or ‘star-like’ cortical and subcapsular opacities by their 50’s.

Image showing a ‘Christmas tree’ cataract. Note the reticular network of colourful needle-shaped opacities. Image courtesy of Zahir and Tahri.

Atopic dermatitis

Around 10% of patients with atopic dermatitis develop cataracts in their 20’s to 40’s
These are usually bilateral and progress quickly

Cataract features

‘Shield-shaped’ anterior subcapsular plaques are characteristic
Posterior subcapsular plaques may occur

Bilateral anterior subcapsular cataracts (A, right; B, left) in a paediatric patient with atopic dermatitis. Image courtesy of Tatham.

Neurofibromatosis type 2

Early cataracts develop in over 60% of patients

Cataract features

Various cataracts can develop - posterior, subcapsular, capsular, cortical or mixed

Radiology in Focus

Imaging plays a significant role in the assessment of cataracts associated with systemic diseases. While the diagnosis of cataracts is primarily clinical, radiological techniques can provide valuable insights into the characteristics and progression of cataracts in patients with underlying systemic conditions. Here are imaging techniques that may be used:

Ultrasound biomicroscopy (UBM)

UBM is particularly useful for visualising the anterior segment of the eye, allowing for detailed assessment of cataract morphology and any associated anterior segment abnormalities.

UBM showing mixed posterior cataract. Image source.

Optical Coherence Tomography (OCT)

OCT provides high-resolution cross-sectional images of the lens and can help identify specific cataract patterns associated with systemic diseases. It is especially useful for evaluating posterior subcapsular cataracts.

OCT showing posterior polar cataract. Image source.

B-scan Ultrasound

B-scan ultrasound can be used to assess the posterior segment of the eye, particularly in cases where cataracts obscure the view of the fundus. It can help identify any associated retinal or vitreous pathology.

B-scan ultrasound showing cataract. Image source.

References

Salmon, John F., and Jack J. Kanski. Kanski’s Clinical Ophthalmology: A Systematic Approach. Ninth Edition, Elsevier, 2020.
Basic Clinical Science Course (BCSC) of the American Academy of Ophthalmology. Section 11. 2006 - 2007.
Park, Jung Hyun. ‘Transient Bilateral Cataract during Intensive Glucose Control: A Case Report’. Journal of Medical Case Reports, vol. 11, no. 1, Dec. 2017, p. 107. DOI.org (Crossref), https://doi.org/10.1186/s13256-017-1268-5.
Zahir, Fadoua, and Hicham Tahri. ‘A Christmas Tree Cataract’. The Pan African Medical Journal, vol. 18, Aug. 2014, p. 332. PubMed Central, https://doi.org/10.11604/pamj.2014.18.332.4780.
Tatham, Andrew. ‘Atopic Dermatitis, Cutaneous Steroids and Cataracts in Children: Two Case Reports’. Journal of Medical Case Reports, vol. 2, no. 1, Apr. 2008, p. 124. BioMed Central, https://doi.org/10.1186/1752-1947-2-124.

Author(s)

Jessica Mendall

Jessica is a final year medical student studying in London. She previously studied preclinical medicine in Oxford, intercalating in Systems Neuroscience and Molecular Pathology. She is particularly interested in Ophthalmology, medical education and clinical research.

Dr Abhiyan Bhandari

Abhiyan is the Co-Founder and Radiology & Imaging Lead of Ophtnotes. He is a doctor who graduated from UCL Medical School in London. He scored in the top 10% of candidates who sat the Duke Elder examination and runs ophthalmology and Duke Elder revision sessions aimed at medical students. He also runs a YouTube channel aimed at medical students, covering topics ranging from study tips, productivity and vlogs of his journey through medical school.

Published: 23/8/22

Last updated: 29/1/25