Cataract is currently the leading cause of visual impairment worldwide with age being the most common cause of lenticular opacification. As cataract surgery is the most commonly performed elective surgery worldwide, forecasts of an increasing number of elderly individuals make it clear that efficient and evidence based models for managing cataract in the future need to be implemented to manage the broadening gap between intervention and available resources.

Bilateral cataract is currently treated using same day separate surgical procedures (immediate sequential bilateral cataract surgery (ISBCS) or on separate days (delayed sequential bilateral cataract surgery (DSBCS). Whether one approach is more ideal than the other is an ongoing debate. There is, however, a clear advantage of same day surgery on resource management.

The primary purpose of this clinical study is to measure the patient reported satisfaction regarding vision in a group of 300 participants following either same day or delayed bilateral cataract surgery.

In this study, patient reported satisfaction in regards to vision is measured using a questionnaire based on the validated Catquest-7SF questionnaire. This is a 7-item self-report scale with both general questions related to difficulties in performing daily activities and satisfaction with vision, as well as questions assessing performance in specific daily activities. Each question has multiple predefined response categories ranging from "very great difficulty" to "no difficulty". One question has response categories ranging from "very dissatisfied" to "very satisfied". All questions have a "can't say"-response category. Each response will be translated to a numerical value used to score the participants.

In addition to the Catquest-7SF, the questionnaire used will also include questions related to satisfaction with the surgical approach (same day or delayed) and experiences with and knowledge of complex visual hallucinations.

The additional questions about complex visual hallucinations are used to measure prevalence and knowledge of Charles Bonnet Syndrome among participants referred to elective cataract surgery.

The study is a prospective, randomized cohort study and will include 300 consecutive patients referred to our department for elective bilateral cataract surgery. Eligible patients who provide consent will be randomly allocated in a group of either same day bilateral surgery or surgery on two days separated by one week. In case of serious surgical complications in the same day group, surgery of the second eye will be postponed and the participant will be placed in a new, separate group.

During a preoperative visit to the department, participants will fill out the questionnaire regarding vision and be subjected to the routine clinical ophthalmic examination which includes biometry and refraction status. One day post-surgery, participants will be contacted by phone regarding their vision. One-week post-surgery, participants will undergo a check-up visit that includes the same examinations as the preoperative visit, except for biometry. Three months post-surgery, participants will once again be contacted by phone or letter and asked to fill out the questionnaire again.

Inclusion Criteria:

• Patients planned for bilateral cataract surgery with monofocal intraocular lens implantation in the bag.
• Patients who agree to be randomly allocated to either ISBCS or DSBCS

Exclusion Criteria:

• Patients at risk of intra- og postoperative complications or where delayed visual rehabilitation is expected (e.g. glaucoma, anterior chamber depth 2,3 or less, corneal endothelial dystrophy)
• Patients with axial lengths < 21 mm or > 27 mm
• Patients in need of immediate surgery
• Patients only eligible to one group, e.g. those requiring general anesthesia where ISBCS is the preferred approach
• Patients unable to read, understand or fill out the questionnaire

No masking: The patients will be informed of the type of procedure they will undergo.