Evaluating Changes in Apparent Chord Mu after Pharmacological Pupil Dilatation

Area of Science:

• Ophthalmology
• Ophthalmic Surgery
• Biometry

Background:

• Preoperative apparent chord mu length > 0.6 mm is linked to photic phenomena risk with multifocal intraocular lenses (MFIOLs).
• Accurate preoperative assessment is crucial for MFIOL patient selection.

Purpose of the Study:

• To evaluate the impact of pharmacological pupil dilatation on apparent chord mu length measurements.
• To determine if pupil size and dilation status influence apparent chord mu length relevant to MFIOL selection.

Main Methods:

• Retrospective analysis of 87 eyes undergoing cataract surgery with IOLMaster 700 biometry.
• Measurement of apparent chord mu length under photopic conditions, before and after pupil dilation.
• Multivariate linear regression to identify predictors of apparent chord values.

Main Results:

• Mean chord mu length increased significantly post-dilation (right eye: 0.32 to 0.41 mm; left eye: 0.29 to 0.40 mm).
• Post-dilation, 16.1% of eyes initially below 0.6 mm exceeded this threshold.
• Seven eyes (8.0%) were already ≥ 0.6 mm pre-dilation.

Conclusions:

• Pharmacological pupil dilatation significantly increases apparent chord mu length.
• Pupil size and dilation status are critical factors in MFIOL patient selection based on apparent chord mu.
• Consider dynamic pupil changes for accurate risk assessment in MFIOL implantation.