The goal of this clinical trial is to learn if laser blended vision (LBV) works better than traditional monovision LASIK to correct presbyopia in adults aged 40 to 55 years. Presbyopia is an age-related condition that makes it hard to see things up close. The study will also evaluate the safety of both procedures.

The main questions it aims to answer are:

Does LBV improve distance, intermediate, and near vision at the same time after surgery? Is LBV as safe as traditional monovision LASIK?

Researchers will compare laser blended vision to traditional monovision LASIK to see if LBV provides better overall vision after surgery.

Participants will:

Be randomly assigned to receive either laser blended vision or traditional monovision LASIK Have standard eye examinations before surgery Undergo LASIK surgery using the assigned method Return for follow-up visits at 1 week, 1 month, 3 months, and 6 months after surgery Complete vision tests and questionnaires about visual quality and satisfaction

Presbyopia is an age-related condition that causes difficulty seeing at near distance and often leads to visual fatigue and dependence on reading glasses. Corneal refractive surgery has become an option for presbyopia correction. Traditional monovision LASIK corrects one eye for distance and the other eye for near vision, but some people may experience reduced depth perception or visual discomfort. Laser blended vision (LBV) is a modified LASIK technique designed to increase depth of focus and improve vision at multiple distances while maintaining binocular visual function. However, high-quality randomized clinical trials comparing LBV with traditional monovision LASIK are limited.

The purpose of this study is to compare the visual outcomes and safety of laser blended vision and traditional monovision LASIK in adults with presbyopia.

This study is a single-center, randomized, parallel-group clinical trial. About 100 participants aged 40 to 55 years who are suitable for LASIK surgery will be enrolled. Participants will be randomly assigned in a one-to-one ratio to receive either laser blended vision or traditional monovision LASIK.

All surgeries will be performed using standard LASIK procedures by experienced surgeons. Participants will undergo routine eye examinations before surgery and will be followed after surgery at scheduled visits, including 1 week, 1 month, 3 months, and 6 months.

The main evaluation will assess whether participants achieve good uncorrected distance, intermediate, and near vision at 6 months after surgery. Additional assessments will include refractive accuracy, visual quality, stereopsis, contrast sensitivity, patient-reported visual function, and safety outcomes.

Inclusion Criteria:

• Adults aged 40 to 55 years with presbyopia
• Suitable candidates for LASIK surgery based on clinical evaluation
• Stable refractive status for at least 1 year
• Best corrected distance visual acuity within normal range
• Willing and able to provide written informed consent
• Willing to comply with study visits and follow-up

Exclusion Criteria:

• Previous ocular surgery
• Corneal disease or abnormal corneal condition that may affect safety
• Significant ocular disease affecting visual function
• Severe dry eye or other ocular surface disorders
• Systemic disease that may affect study participation
• Inability to tolerate monovision or anisometropia
• Any condition that the investigator considers unsuitable for the study