Effect of Preoperative Pupil Size on Quality of Vision After Wavefront-Guided LASIK

Purpose: To prospectively evaluate the effect of preoperative pupil size on quality of vision after wavefront-guided LASIK.

Methods: Fifty-one patients underwent LASIK for low myopia and completed questionnaires regarding specific visual symptoms before and after surgery. Each eye was evaluated postoperatively at 1-week, 1-, 3-, 6- and 12-months. Pupils were stratified according to size: small (<5.5mm), medium (5.5 to 6.0mm) and large (>6.0mm). Mesopic pupil size and preoperative and postoperative variables were evaluated using analysis of variance (ANOVA). A regression model was also performed to determine the correlation between mean spherical equivalent and cylinder and visual symptoms.

Inclusion criteria

• no more than 6.00 D of spherical myopia
• no more than 3.00 D of refractive astigmatism
• a stable refraction (less than 0.50D per year of sphere or cylinder)
• a corneal diameter of less than 11.0 mm to allow for suction ring fixation
• discontinuation of soft contact wear at least 7 days prior to preoperative evaluation
• visual acuity correctable to at least 20/20
• age older than 21 years
• ability to participate in follow-up examinations for 12 months after LASIK surgery

Exclusion criteria

• use of rigid gas permeable contact lens
• severe dry eye symptoms
• severe blepharitis
• anterior segment abnormalities (i.e. cataracts, corneal scarring, or neovascularization within 1 mm of intended ablation zone)
• recurrent corneal erosion
• severe basement membrane disease
• progressive or unstable myopia or keratoconus
• unstable corneal mires on central keratometry
• corneal thickness in which LASIK procedure would result in less than 250 microns of remaining posterior corneal thickness below the flap postoperatively
• baseline standard manifest refraction of more than 0.75 D in sphere power
• or a difference of greater than 0.50 D in cylinder power compared with baseline standard cycloplegic refraction
• a baseline standard cycloplegic refraction differing more than 0.75 in sphere, 0.50 D in cylinder
• have a different type of astigmatism (i.e. with-the-rule) when the cylinder is greater than 0.50D compared to baseline standard cycloplegic refraction
• preoperative assessment of ocular topography and/or aberrations indicates that either eye is not suitable candidate for LASIK vision correction procedure (i.e. forme fruste keratoconus
• corneal warpage, or pellucid marginal degeneration)
• previous intraocular or corneal surgery
• history of herpes zoster or simplex keratitis
• patients on systemic corticosteroid or immunosuppressive therapy
• immunocompromised subjects or clinically significant atopic disease
• connective tissue disease
• diabetes
• steroid responder
• macular pathology
• pregnant or lactating patients
• patients with sensitivity to planned study concomitant medications
• patients participating in another ophthalmic drug or device clinical trial