A Wide Discrepancy between Intraocular Pressure by Applanation and Non-contact Tonometry after LASIK

ABSTRACT

PURPOSE: To report the case of a glaucoma patient with a history of LASIK surgery who presented with a wide discrepancy in intraocular pressure between the Goldmann applanation tonometry and non-contact tonometry. METHODS: A 20-year-old male glaucoma patient was referred to our clinic with a chief complaint of blurred vision in his right eye. The patient had a history of uneventful bilateral LASIK surgery. Upon our initial examination, his best-corrected visual acuity in the right eye was 0.04 and his right eye IOP was 14 mmHg by Goldmann applanation tonometry and 40 mmHg by non-contact tonometry. A slit lamp examination showed corneal epithelial edema with diffuse interface opacities. The central corneal thickness in the right eye was 587 micrometer. An ultrabiomicroscopy demonstrated an interface fluid accumulation between the LASIK flap and the stromal bed. The patient was diagnosed with juvenile open-angle glaucoma and was scheduled for a trabeculectomy. RESULTS: Seven days after trabeculectomy, the patient's vision in the right eye improved to 0.7 and his IOP was 12 mmHg by Goldmann applanation tonometry and 14 mmHg by non-contact tonometry. In addition, the corneal epithelial edema, interface opacities, and fluids had all resolved and the central corneal thickness was reduced to 489 micrometer. CONCLUSIONS: In eyes that have undergone LASIK surgery, the IOP measured by Goldmann applanation tonometry may underestimate the true pressure due to fluid accumulation under the LASIK flap. In such cases, non-contact tonometry can be a convenient and a reliable method for determining treatment plan.