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We present a complication arising from the use of swimming goggles in a patient with glaucoma drainage blebs.
A 73 year old white man with poorly controlled primary open angle glaucoma underwent routine trabeculectomy with adjunctive 5-fluorouracil to the right eye, followed by the same procedure to the left eye 6 weeks later. Preoperatively the intraocular pressures were 28 mm Hg bilaterally and cup:disc ratios were 0.95 right, 0.8 left. Early postoperative intraocular pressure (IOP) in the right eye was low (5 mm Hg at weeks 2 and 6), but uncomplicated. The recovery of the left eye was uneventful, and at 3 months the IOPs were 10 mm Hg right eye, 12 mm Hg left.
However, at 4 months the patient presented with discomfort and redness in the right eye. A large extension of the bleb had formed at the nasal limbus, with an associated corneal dellen (fig 1A and B). The IOP had increased in the right eye, which was treated with a needling procedure and 5-FU injection, repeated 3 weeks later. Subsequently the bleb extension receded and the previously elevated right nasal conjunctiva was found to be firmly adherent to the underlying sclera (fig 1C).
He re-presented 7 months after the initial surgery with redness and swelling, this time in the left nasal conjunctiva (fig 1D). At this point the patient mentioned that he was a keen swimmer and inquired whether his problem could have been caused by the use of swimming goggles. He had resumed regular swimming 2 weeks before developing the right eye complication, then stopped. He had resumed again 3 months before developing the left.
With this in mind, we set out to investigate the pressure changes inside swimming goggles. With a pressure transducer fixed to one eyepiece (fig 1E), we recorded a comfortable range of −1 to −5 mm Hg, discomfort over −10 mm Hg and a maximum suction of −44 mm Hg. Upon removing the goggle, a transient negative pressure spike was also produced (fig 1F). Given these observations and the timing of the clinical events, we surmise that the patient’s bleb extensions were plausibly consequent upon his aquatic activities.
Previous reports of barotrauma sustained while wearing overtight goggles include suction petechiae1 and changes in the eyelid skin,2 but we are not aware of any information concerning the effects of swimming goggles on glaucoma drainage blebs. When goggles are applied, firm pressure displaces a small volume of air and creates a negative “intragoggle” pressure, the basis by which a seal is maintained. In a person who has undergone trabeculectomy, an increase in the transconjunctival pressure gradient could open up a weakness in the perimeter of the bleb and cause it to extend in the direction of least resistance.
Other experimental work has examined the pressure changes occurring in the mask space during scuba diving.3 This is a rather different system as the nose is included in the mask, allowing the pressure to be equalised by exhaling through the nose. The eye and periocular structures can be subjected to significant negative pressures if this is not done, but the duration is usually limited by this pressure gradient acting across the tympanic membrane, causing pain and prompting the diver to ascend or equalise. Ocular barotrauma can result in subconjunctival haemorrhage and chemosis, and it has been recommended that patients wait a minimum of 2 months after glaucoma filtering surgery before resuming scuba diving.4
We do not believe patients who have undergone trabeculectomy need to cease swimming, but they should be aware that goggles may be able to produce excessive negative pressure if they form a very tight seal.