An observational study in Optic Nerve Diseases, sponsored by Yağmur Malkoc. Not yet recruiting. Open to participants aged 18 Years to 45 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-10.
Sponsored by Yağmur Malkoc · Observational
Le Fort I osteotomy is a common jaw surgery that includes a step called pterygomaxillary dysjunction, during which force applied with a surgical instrument (osteotome) can be transmitted toward the eye socket (orbit) and the optic nerve canal. Serious eye complications after this surgery are rare, but it is not known whether smaller, subclinical changes occur in the optic nerve that go unnoticed without special testing. This study uses a non-invasive eye imaging test called optical coherence tomography (OCT) to measure the thickness of the nerve fiber layer around the optic nerve, before and after Le Fort I surgery, to find out whether such changes occur.
Fifty patients aged 18-45 years scheduled for isolated Le Fort I osteotomy or Le Fort I osteotomy combined with bilateral sagittal split osteotomy (BSSO) will be enrolled in this single-center, prospective, observational cohort study. Each patient serves as their own control (within-subject comparison across time points). All participants will undergo ophthalmologic examination, RNFL-OCT imaging, optic disc morphology assessment (disc area, elongation ratio, presence of disc head hemorrhage), and Humphrey 30-2 visual field testing at three time points: preoperatively (T0, within 1 week before surgery), 1 week postoperatively (T1), and 3 months postoperatively (T2). All ophthalmologic measurements will be performed by a single examiner blinded to intraoperative surgical details, using the same device throughout. Maxillary advancement amount and pterygomaxillary junction depth/concavity angle will be measured preoperatively on CBCT (pterygomaxillary junction measured bilaterally, with Observer 1 measuring twice for intraobserver reliability and Observer 2 measuring once for interobserver reliability). No intervention, randomization, or treatment-group allocation occurs as part of this study; all participants receive their routine, already-planned orthognathic surgical care. A priori power analysis (G*Power, RM ANOVA within-between interaction, f=0.25, epsilon=1, alpha=0.05, power=0.90) indicated a minimum required sample size of N=36; n=50 was set to allow for attrition.
61 studies on the registry are indexed under Optic Nerve Diseases; 22 are open to participants now.
This study's planned enrollment of 50 is below the median of 56 across 21 observational studies indexed under Optic Nerve Diseases.
Browse Optic Nerve Diseases studies →Yağmur Malkoc is the lead sponsor of 3 studies on the registry; 1 is open to participants now.
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The criteria were revised on the registry on Nov 10, 2026. See what changed
Adult patients aged 18-45 years scheduled for isolated Le Fort I osteotomy or Le Fort I combined with bilateral sagittal split osteotomy (BSSO) at Istanbul Medipol University, with no pre-existing ocular or orbital pathology that could independently affect retinal nerve fiber layer thickness or optic disc morphology.'
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Exclusion Criteria:
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You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients undergoing isolated Le Fort I osteotomy or Le Fort I combined with bilateral sagittal split osteotomy (BSSO). No randomization or treatment allocation; all participants receive their routine, already-planned orthognathic surgical care. Diagnostic Test: RNFL-OCT and optic disc morphology assessment (disc area, elongation ratio, disc head hemorrhage), performed preoperatively (T0) and at 1 week (T1) and 3 months (T2) postoperatively. Diagnostic Test: Humphrey 30-2 visual field testing, performed at the same three time points. Diagnostic Test: Preoperative CBCT measurement of pterygomaxillary junction depth and concavity angle, and maxillary advancement amount from surgical planning data.
Diagnostic Test: RNFL-OCT and Optic Disc Assessment · Diagnostic Test: Diagnostic Test · Diagnostic Test: Preoperative CBCT Measurement of Pterygomaxillary Junction
Peripapillary retinal nerve fiber layer thickness and optic disc morphology (disc area, elongation ratio, presence of disc head hemorrhage) measured by optical coherence tomography, performed preoperatively (T0) and at 1 week (T1) and 3 months (T2) postoperatively.
Humphrey 30-2 Visual Field Testing Açıklama: Standard automated perimetry (Humphrey 30-2 program) performed at the same three time points (T0, T1, T2) to assess mean deviation and pattern standard deviation.
Cone-beam computed tomography measurement of pterygomaxillary junction depth and concavity angle, and maxillary advancement amount from virtual surgical planning data, obtained preoperatively.
Change in Peripapillary Retinal Nerve Fiber Layer (RNFL) Thickness
Change in peripapillary retinal nerve fiber layer (RNFL) thickness, measured by optical coherence tomography (OCT), from baseline (T0, preoperative) to 1 week (T1) and 3 months (T2) after Le Fort I osteotomy.
Time frame: Baseline (T0, preoperative) to 3 months (T2) postoperatively
Change in Optic Disc Area and Elongation Ratio
Change in optic disc area and elongation ratio (vertical/horizontal), measured by OCT, from baseline (T0) to 1 week (T1) and 3 months (T2) after Le Fort I osteotomy.
Time frame: Baseline (T0) to 3 months (T2) postoperatively
No study locations are listed for this record.
Plan to share: No
No publications or documents are linked to this record.
Start is estimated for Nov 2026; primary completion for Apr 2028, 17 months later.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Nov 2026. You cannot join it, but the record below documents what was studied.
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