By Earl R. Nichols

ANAHEIM, CA -- November 19, 2003 -- People with obstructive sleep apnoea may also be at risk for developing glaucoma, according to some American ophthalmologists. This group feels the association is great enough that they are now including questions about sleep disorders on their patients' medical histories.

The surprising results of one of these questionnaires were presented at the 2003 Annual Meeting of the American Academy of Ophthalmology, held here November 15-18. Rick Bendel, MD, ophthalmology, Mayo Clinic, Jacksonville, Florida, United States, noted that, of 83 of his patients with confirmed sleep apnoea, 33% had glaucoma, and of those, 63% were confirmed through visual field progression and examination of the optic nerve. For another 17% of patients glaucoma was confirmed based on examination of the optic nerve alone.

It is well known that people with sleep apnoea run an increased risk of car accidents, myocardial infarction and a host of other events, but, said Dr. Bendel, "perhaps we should now be adding the increased risk of glaucoma to the list, and telling them that their sleep apnoea could have having a significantly detrimental impact on their eyes."

Dr. Bendel conducted the study because sleep apnoea is known to affect oxygenation, neurohumoural factors and circulatory haemodynamics, and he suspected that these factors could be having an effect on the integrity of the optic nerve.

Prior studies involving small groups of patients, or patients in 1 family have found a similar association between sleep apnoea and glaucoma, Dr. Bendel noted.

Dr. Bendel said that in his study, there was no link between age, sex and body mass index (BMI) with the presence of glaucoma. There was, however, evidence that the patient's intraocular pressure (IOP) increases as BMI increases, and that mean IOP was lower among the male subjects than it was in females.

The study did not find a link between glaucoma and age, which is unusual in that virtually every other study conducted has deemed age to be one of the strongest risk factor for the development of glaucoma.

Karanjit Kooner, MD, University of Texas Southwestern, Dallas, United States, discussed Dr. Bendel's findings and said, "This is another important risk factor for us to consider."

Sleep disorders play a critical role in patients with glaucoma, said Dr. Kooner, adding that he now makes questions about patients' sleep disorders a routine part of his medical history-taking.