Abstract
Abstract: :
Purpose: There are 20 million certified scuba divers world-wide and millions of people undergoing cornea and refractive procedures each year. These demographic groups have great overlap.1,2 The question of safety after cornea and refractive procedures has not been objectively examined under actual dive conditions. While hyperbaric studies examine pressure, other paramenters such as salt, mask squeeze, and inability to equalize are unique to actual scuba dives.3 This study examines corneal and pressure parameters in actual recreational diving situations. Methods: Twelve scuba divers participating in recreational dives at the Akumal Dive Center in Quintana Roo, Mexico over a five-day span volunteered to be study participants. Slit lamp exam and measurements of visual acuity, pachymetry, tonometry were performed immediately prior to dives and within 20 minutes of surfacing (mean time=15.4 min). Results: Twenty four eyes were measured bilaterally for a total of 25 dives ranging from 34 feet to 100 feet in depth (mean depth 69.9 feet, mean time 45.6 minutes). Corneal thickness decreased an average of 1.9% in the post-dive state; an average of 9.4±10.1 microns. Intraocular pressure (IOP) increased an average of 17% in the post-dive state; an average of 2.3±1.8 mmHg. Participants lost an average of three letters of a line of vision immediately post-dive. There was little correlation between pachymetry and IOP with relation to depth or dive duration. We measured a negative 0.5 correlation coefficient between the corneal thickness and IOP. Average post-dive corneal thickness returned to within 0.008% of the initial measurement within 24 hours after the last dive. Average post-dive IOP returned to 1.9% of the initial IOP within 24 hours after the last dive. Visual acuity 24 hours post-dive normalized within 24 hours. Conclusions: Corneal thickness does not deviate significantly after a scuba dive, though it does demonstrate minimal thinning. There was no correlation in depths up to 100 feet or dive times greater than one hour. IOP showed elevation in the post-dive state and negatively correlated with corneal thinning. Visual acuity, pachymetry, and IOP normalize within 24 hours of the last dive. This may help lend greater confidence in telling patients recreational diving is safe after cornea and refractive procedures. 1. Khan-Lim D, et al. Defining the content of patient questionnaires: reasons for seeking laser in situ keratomileusis for myopia. J Cat Refract Surg. 2002 May;28(5):788-94. 2. "Diver Statistics";www.PADI.com. 3. Peters, NT et al. Effect of increased atmospheric pressure on radial keratotomy. J Cat Refract Surg. 1999 Dec;25(12):1620-3.
Keywords: cornea: clinical science • refractive surgery: complications • intraocular pressure