Changes in Foveal Fixation Axis Position Between Seated and Supine Postures and Their Potential Applications in...

Area of Science:

• Ophthalmology
• Optometry
• Surgical Technology

Background:

• Accurate centration of laser ablation in refractive surgery remains a challenge.
• Current methods use pupillary center or corneal vertex, not ideal for optimal visual outcomes.
• The foveal fixation axis (FFA) is proposed as a more accurate alignment point.

Purpose of the Study:

• To evaluate a new device for centering ophthalmic lenses using the foveal fixation axis (FFA).
• To assess the repeatability and patient satisfaction with FFA-guided progressive addition lens adaptation.
• To investigate the potential of FFA measurements as a reference for laser ablation centration in refractive surgery.
• To analyze the positional changes of the FFA when a patient moves from a seated to a supine position.

Main Methods:

• A novel device was used to measure and center lenses based on the foveal fixation axis (FFA).
• Repeatability of the device was assessed.
• Patient adaptation and satisfaction were evaluated for progressive addition lenses centered with FFA measurements.
• The change in FFA position was analyzed between seated and supine patient positions.

Main Results:

• The device demonstrated acceptable repeatability for FFA measurements.
• Patients using FFA-centered progressive addition lenses showed high adaptation rates and satisfaction.
• The study identified potential shifts in FFA position with changes in patient posture.

Conclusions:

• Foveal fixation axis (FFA) measurements are suitable for progressive addition lens adaptation.
• FFA measurements show promise as a reference for improving laser ablation centration in refractive surgery.
• Understanding FFA positional changes with patient repositioning is crucial for refractive surgery planning.