Clinical trial NCT04831177: Thin-Flap Laser in Situ Keratomileusis Associated Dry Eye
Official title: Thin-Flap Laser in Situ Keratomileusis Associated Dry Eye
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Myopic LASIK Candidates With Spherical Equivalent up to - 10 Diopters
Keywords: Dry eye
Femtolaser
Laser in situ keratomileusis
Lead sponsor: Assiut University
Sponsor class: OTHER
First posted: 2021-04-05
Enrollment: 55
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: Laser in situ keratomileusis (LASIK) eye surgery continues to be the most common refractive procedure used to correct different forms of ametropia. Although the introduction of femtosecond technology has markedly reduced the incidence of intraoperative flap complications and allowed a better control on flap parameters, dry eye remains one of the most challenging postoperative complications.

Detailed description: The pathophysiology of post LASIK dry eye is not clear; however, many mechanisms have been suggested including inflammation, loss of conjunctival goblet cells during suction, exacerbation of a preexisting dry eye, abnormal interaction between the lid margins and the ocular surface. Intact corneal sensation is crucial for proper tear production and distribution on the ocular surface as well as maintaining the normal dynamics of eyelid blinking. Disruption of corneal nerves in LASIK decreases the release of neurotrophic factors necessary for the normal function of the corneal epithelium as well as the integrity of the lacrimal functional unit, a condition referred to as LASIK induced neurotrophic epitheliopathy (LINE) that largely contributes to the development of post- LASIK dry eye .

Many studies evaluated the incidence of post-refractive dry eye after LASIK compared to flapless laser vision correction (LVC) procedures such as PRK and small incision lenticule extraction (SMILE). The aim of this study is to assess and compare different dry eye parameters following LASIK with planned thin flaps created by femtosecond laser (FS) and mechanical microkeratome (MK).

Eligibility criteria: Inclusion Criteria:

1. Candidates for Laser Vision Correction (LVC).
2. Eyes with spherical equivalent (SE) up to - 10 diopters (D),
3. Corneal thickness at thinnest location of ≥ 500 um and estimated postoperative residual stromal bed of at least 300 um

Exclusion Criteria:

1. Patients with symptoms or signs of dry eye (TBUT \<10 sec, Schirmer I test \<10mm and Ocular Surface Disease Index OSDI score \>13),
2. Posterior blepharitis, contact lens wearers ,
3. Ocular surface disease ,
4. Systemic diseases contraindicating LASIK and previous ocular surgery.

Primary outcomes:
measure: Tear film break up time TBUT
timeFrame: 6 months
measure: Schirmer I test
timeFrame: 6 months
measure: Ocular Surface Disease Index OSDI
timeFrame: 6 months
measure: Lower Tear meniscus height (LTMH)
timeFrame: 6 months
measure: Lower Tear meniscus area (LTMA)
timeFrame: 6 months
Secondary outcomes:
Other outcomes:
Locations:
city: Assiut
country: Egypt
facility: TIBA eye center
Study officials:
References:
citation: Sambhi RS, Sambhi GDS, Mather R, Malvankar-Mehta MS. Dry eye after refractive surgery: a meta-analysis. Can J Ophthalmol. 2020 Apr;55(2):99-106. doi: 10.1016/j.jcjo.2019.07.005. Epub 2019 Aug 20.