The effect of pharmacological pupillary dilation on intraocular pressure measurement.

OBJECTIVE: To measure the difference in intraocular pressure (IOP) before and after pharmacologic mydriasis in normal subjects using Goldmann applanation tonometer (GAT) and the Diaton transpalpebral tonometer (DT). DESIGN: Prospective case series study. PARTICIPANTS: Sixty-seven adult patients attending a tertiary general ophthalmology eye care center. METHODS: Patients were recruited based on a lack of glaucoma history and normal anterior segment on slit lamp examination. IOP measurements predilation and postdilation were collected. Predilation, both eyes were measured using GAT followed immediately by DT. Forty-five minutes post pharmacologic mydriasis, the measurements were repeated sequentially in the same order. Central corneal thickness (CCT) and additional parameters were also collected to corroborate the absence of glaucoma. RESULTS: Using GAT, the mean IOP predilation was 16.7 ± 3.1 mm Hg OD and 16.12 ± 3.0 mm Hg OS. The mean difference between predilation and postdilation time-points was -1.1 ± 2.5 mm Hg in the right eye and -0.7 ± 2.3 mm Hg in the left eye. Using DT, the mean IOP predilation was 12.8 ± 3.8 mm Hg OD and 13.2 ± 3.5 mm Hg OS. The mean difference between predilation and postdilation time points was -0.8 ± 4.0 mm Hg in the right eye and -0.7 ± 3.6 mm Hg in the left eye. There was a larger fluctuation of postdilation measurements using DT. The difference in IOP measured by the 2 instruments was statistically significant both predilation and postdilation (paired sample analysis pre-correlation 0.38 p = 0.002; post correlation 0.40 p = 0.001). CONCLUSIONS: The use of pharmacologic mydriasis affected the reliability of IOP measurements which was decreased when taken postdilation by both GAT and DT. The poor agreement between GAT and DT values indicates an intrinsic difference between the two types of instrumentation.

Pre- versus post-dilation changes in intraocular pressure: their clinical significance.

OBJECTIVE: To measure the difference in intraocular pressure (IOP) before and following pharmacologic mydriasis with a cycloplegic-mydriatic combination agent in normal subjects using the Goldmann applanation tonometer. DESIGN: A prospective, university hospital-based, nonrandomized interventional case series. METHODS: We recruited 67 normal subjects without glaucoma. Data were collected on the patients' IOPs before and 45 minutes after pharmacologic mydriasis in both eyes using the Goldmann applanation tonometer. Central corneal thickness and additional parameters were measured to further confirm the absence of glaucoma and to study the correlation between IOP fluctuations and these characteristics. RESULTS: The IOP was measured in 127 eyes. The mean difference between pre- and post-dilation time points was 1.1 ± 2.5 mm Hg in the right eye and 0.7 ± 2.3 mm Hg in the left eye. Post-dilation, the maximum deviation was a change of 6 mm Hg.; 35% of patients had a post-dilation variation of >2 mm Hg (clinically significant). Of these, 31.1% of changes were IOP increases, and 68.9% of changes were IOP decreases after dilation. Central corneal thickness and other parameters showed no correlation with IOP changes. CONCLUSIONS: The use of pharmacologic mydriasis prior to IOP measurement affected the reliability of IOP measurements taken post-dilation in our group of patients. Thus, we believe that the stringent measurement of IOP prior to dilation is the responsible method of measuring and following IOP in every single patient.

Pigment dispersion and recurrent hyphema associated with in-the-bag lens implantation.

We present the case of a patient who experienced recurrent episodes of blurry vision and eye pain after uneventful cataract extraction and in-the-bag intraocular lens (IOL) implantation. Examination revealed a microhyphema and signs of pigment dispersion. Iris transillumination was seen overlying areas where the IOL optic was not covered by the anterior capsule. Anterior segment optical coherence tomography confirmed iris indentation by the IOL optic, which was alleviated by performing laser peripheral iridotomy. This case shows that IOLs in the capsular bag can erode the posterior surface of the iris and that an adequately sized capsulorhexis should be performed to ensure anterior capsule coverage. Laser peripheral iridotomy should be considered when significant posterior iris bowing is observed.