BMJ  2006;332:179 (21 January), doi:10.1136/bmj.332.7534.179-a

Letter

Funduscopy: to dilate or not?

Other drugs can cause partial pupil dilatation

Editor—Liew et al highlight the very small risks associated with precipitating an attack of angle closure glaucoma when dilating a pupil for the purposes of funduscopy.¹

The initiating event in acute angle closure glaucoma is incomplete mydriasis (pupil dilatation) resulting in pupil block and the prevention of aqueous drainage through the trabecular meshwork. This partial mydriasis is normally caused by poor ambient lighting conditions, but drugs with adrenergic and anticholinergic properties have also been identified as causative agents. These drugs include ipratropium and tricyclic antidepressants.^{2 3} Serotonin selective reuptake inhibitors (SSRIs) such as paroxetine and fluoxetine have also been implicated through their anticholinergic properties.⁴

The British National Formulary advises caution with using these drugs in patients with a history of angle closure glaucoma.⁵ This is, however, misleading, as patients who have had an attack of angle closure glaucoma will hopefully have been treated with either iridotomies or trabeculectomies and will therefore no longer be at risk. We therefore recommend that all patients taking ipratropium, tricyclics, and SSRIs be warned of the risk of ophthalmic symptoms (painful red eye, blurring of vision, headache, nausea and vomiting), especially those at greater risk (elderly, female, hypermetropic refractive error). This should reduce ocular morbidity in patients who develop this complication.

Princess Alexandra Eye Pavilion, Edinburgh EH3 9HA pete{at}pdcackett.demon.co.uk

---

Competing interests: None declared.

References

1. Liew G, Mitchell P, Wang JJ, Wong TY. Fundoscopy: to dilate or not to dilate? BMJ 2006;332: 3. (7 January.)[Free Full Text]
2. Singh J, O'Brien C, Wright M. Nebulized bronchodilator therapy causes acute angle closure glaucoma in predisposed individuals. Respir Med 1993;87: 559-61.[ISI][Medline]
3. Ritch R, Krupin T, Henry C, Kurata F. Oral imipramine and acute angle closure glaucoma. Arch Ophthalmol 1994;112: 67-8.[Abstract]
4. Browning AC, Reck AC, Chisholm IH, Nischal KK. Acute angle closure glaucoma presenting in a young patient after administration of paroxetine. Eye 2000;14: 406-8.
5. Joint Formulary Committee. British national formulary. 50th ed. London: British Medical Association and Royal Pharmaceutical Society of Great Britain; September 2005.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

Relevant Article

Fundoscopy: to dilate or not to dilate?

Gerald Liew, Paul Mitchell, Jie Jin Wang, and Tien Yin Wong
BMJ 2006 332: 3. [Extract] [Full Text] [PDF]