Presbyopia, Refractive Error
Conditions
Keywords
Presbyopia, LASIK, Laser Blended Vision, Monovision, Refractive Surgery, Randomized Clinical Trial
Brief summary
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
Detailed description
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.
Interventions
PROCEDURELaser Blended Vision LASIK
Laser blended vision LASIK is a refractive surgery technique for presbyopia correction. The dominant eye is corrected for distance vision, and the non-dominant eye is adjusted to mild myopia to improve near vision using a laser blended vision design.
PROCEDURETraditional Monovision LASIK
Monovision LASIK is a refractive surgery technique in which the dominant eye is corrected for distance vision and the non-dominant eye is corrected for near vision to improve presbyopia.
Sponsors
Zhongshan Ophthalmic Center, Sun Yat-sen University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
40 Years to 55 Years
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Proportion of participants achieving target binocular visual acuity at multiple distances | 6 months after surgery | Proportion of participants who achieve binocular uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), and uncorrected near visual acuity (UNVA) of 0.8 (logMAR 0.10) or better. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Binocular uncorrected visual acuity | 1 week, 1 month, 3 months, and 6 months after surgery | Binocular uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), and uncorrected near visual acuity (UNVA) will be measured at scheduled follow-up visits. |
| Refractive accuracy after surgery | 1 week, 1 month, 3 months, and 6 months after surgery | Refractive accuracy will be evaluated using the difference between achieved and target refraction and the proportion of eyes within predefined refractive ranges. |
| Refractive stability over time | Up to 6 months after surgery | Refractive stability will be assessed by changes in spherical equivalent during follow-up visits. |
| Contrast sensitivity | 1 week, 1 month, 3 months, and 6 months after surgery | Contrast sensitivity will be measured using a standardized contrast sensitivity testing system (CSV-1000, VectorVision, USA) at multiple spatial frequencies. |
| Stereoacuity | 1 week, 1 month, 3 months, and 6 months after surgery | Stereoacuity will be measured using a standardized stereopsis test (Randot Stereo Test) at near distance to evaluate binocular visual function. |
| NEI Visual Function Questionnaire-25 (NEI VFQ-25) | 1 week, 1 month, 3 months, and 6 months after surgery | Vision-related quality of life will be assessed using the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25). The questionnaire includes multiple domains related to visual function and daily activities. Scores range from 0 to 100, with higher scores indicating better visual function. |
| Quality of Vision (QoV) questionnaire | 1 month, 3 months, and 6 months after surgery | Visual symptoms will be assessed using the Quality of Vision (QoV) questionnaire, which evaluates the frequency, severity, and bothersome nature of visual disturbances such as glare, halos, starbursts, blur, and visual distortion. Responses are recorded on ordinal scales, and higher scores indicate worse visual quality. |
| Spectacle independence | 1 month, 3 months, and 6 months after surgery | Spectacle independence will be assessed using a structured questionnaire evaluating the need for glasses or contact lenses for distance, intermediate, and near vision, as well as the frequency of use during daily activities. Higher levels of independence indicate better functional visual outcomes. |
| Visual safety outcomes | 1 week, 1 month, 3 months, and 6 months after surgery | Visual safety will be evaluated by changes in corrected distance visual acuity, including loss of one or more lines, loss of two or more lines, and calculation of the safety index. |
| Postoperative complications | From surgery to 6 months after surgery | Postoperative complications and adverse events will be recorded during follow-up, including corneal complications, inflammatory or infectious events and the need for additional treatment. |
Countries
China
Outcome results
None listed