Comparison between Pascal dynamic contour tonometer and Goldmann applanation tonometer after different types of...

Area of Science:

• Ophthalmology
• Refractive Surgery
• Ocular Biomechanics

Background:

• Intraocular pressure (IOP) measurement accuracy is crucial for glaucoma diagnosis and management.
• Refractive surgery like photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) alters corneal biomechanics, potentially affecting IOP readings.
• Comparing different tonometry methods post-refractive surgery is essential for reliable IOP assessment.

Purpose of the Study:

• To compare intraocular pressure (IOP) measurements obtained by Goldmann applanation tonometer (GAT) and Pascal dynamic contour tonometer (PDCT).
• To evaluate the effect of PRK and LASIK on IOP readings from both GAT and PDCT.
• To assess the long-term stability of IOP measurements after refractive surgery.

Main Methods:

• Prospective study involving three patient groups: PRK for myopia, LASIK for myopia, and LASIK for hyperopia.
• IOP measurements using GAT and PDCT were recorded preoperatively and at 1, 3, 6, and 12 months postoperatively.
• Ultrasound pachymetry was performed preoperatively and at 1 month postoperatively to assess corneal thickness.

Main Results:

• GAT consistently yielded lower IOP readings than PDCT across all groups, both preoperatively and postoperatively (p < 0.05).
• Significant decreases in GAT-measured IOP were observed postoperatively in PRK and myopic LASIK groups compared to baseline.
• PDCT measurements showed no statistically significant changes in IOP for any group after refractive surgery.

Conclusions:

• Goldmann applanation tonometry underestimates IOP after myopic PRK, myopic LASIK, and hyperopic LASIK.
• Pascal dynamic contour tonometry provides stable IOP measurements unaffected by these refractive surgical procedures.
• PDCT may offer a more reliable method for IOP monitoring in patients who have undergone refractive surgery.