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The aim is to evaluate the short-term changes in ocular surface measures and tear inflammatory mediators after lenticule extraction (FLEx) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) procedures.
Over the past few years, laser in situ keratomileusis with a femtosecond laser-created flap (FS-LASIK)has been a popular ophthalmic procedure for the correction of refractive error. This first all-in-one FS-laser system was designed to perform the refractive lenticule extraction (ReLEx) procedures, femtosecond lenticule extraction (FLEx).They have the same feature: corneal flap.
Ocular surface disruption during corneal refractive surgery is commonly considered to be closely related to the development of dry eye. Multiple etiologies contribute to this ocular surface disruption, including the flap creation and stromal ablation involved in previous refractive surgery techniques. Corneal nerve damage has been considered the main cause of dry eye, due to disrupted afferent sensory nerves, reduced blink reflex, and increased tear evaporation leading to tear film instability. In addition, postoperative inflammatory mediator fluctuations are also a key factor related to ocular surface damage. Extensive research has described the effects of cytokines, chemokines and growth factors in modulating corneal wound healing, cell migration, and apoptosis on the ocular surface after refractive surgery.
This prospective clinical study is going to assess the short-term changes in ocular surface measures and tear inflammatory mediators after lenticule extraction (FLEx) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) procedures.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| lenticule extraction | Experimental | The patients in this group chose to receive the lenticule extraction surgery |
|
| FS assisted laser in situ keratomileusis | Experimental | The patients in this group chose to receive the femtosecond laser-assisted laser in situ keratomileusis surgery. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| lenticule extraction | Procedure | Four femtosecond incisions were created in succession: the posterior surface of the refractive lenticule (spiral in), the lenticule border, the anterior surface of the refractive lenticule (spiral out), and the corneal flap in the superior region. After the suction was released, the flap was opened using a thin, blunt spatula and the free refractive lenticule was subsequently grasped with a forceps and extracted, after which the flap was repositioned carefully. |
| Measure | Description | Time Frame |
|---|---|---|
| Schirmer I test | up to 1month after surgery | |
| corneal fluorescein staining | up to 1month after surgery | |
| noninvasive tear breakup time | up to 1month after surgery | |
| ocular surface disease index | up to 1month after surgery | |
| central corneal sensitivity | up to 1month after surgery | |
| tear meniscus height | up to 1month after surgery | |
| Interleukin-1α | up to 1month after surgery | |
| tumor necrosis factor-α | up to 1month after surgery | |
| nerve growth factor | up to 1month after surgery | |
| interferon-γ | up to 1month after surgery | |
| transforming growth factor-β1 | up to 1month after surgery | |
| matrix metalloproteinase-9 |
| Measure | Description | Time Frame |
|---|---|---|
| Correlation Between Inflammatory Mediators and Ocular Surface Changes | up to 1month after surgery |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Xingwu Zhong, MD,PhD | Hainan Eye Hospital, Zhongshan Ophthalmic Center of Sun Yat-sen University | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Hainan Eye Hospital, Zhongshan Ophthalmic Center of Sun Yat-sen University | Haikou | Hainan | 570311 | China |
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| ID | Term |
|---|---|
| D009216 | Myopia |
| D001251 | Astigmatism |
| D022125 | Lacerations |
| ID | Term |
|---|---|
| D012030 | Refractive Errors |
| D005128 | Eye Diseases |
| D014947 | Wounds and Injuries |
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| femtosecond laser-assisted laser in situ keratomileusis | Procedure | track distance and spot distance were 3.0 μm during flap creation and 1.5 μm during flap side-cutting. The flap diameter was 8.0 mm, and flap thickness was set to 105 μm. Side-cut angle and hinge angle were 90°and 50° respectively. The flaps were created by laser scanning in spirals from the periphery to the center of the pupil. An excimer laser system was used in the subsequent ablation of the stromal bed with a 6.0 mm optical zone. Once the excimer ablation was completed, the flap was repositioned in a similar fashion as in routine LASIK. |
|
| up to 1month after surgery |