Measurement of Intraocular Pressure in Patients Undergoing Laminectomy in the Prone Position

Measurement of Intraocular Pressure (With Non-contact Tonometer) in Patients Undergoing Laminectomy in the Prone Position: A Clinical Study

Status

Not yet recruiting

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT07067008

Enrollment

Registered

2025-07-15

Start date

2025-08-15

Completion date

2025-10-30

Last updated

2025-07-18

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Intraocular Pressure, Laminectomy, Prone Position

Keywords

Prone Position, Intraocular Pressure, Laminectomy

Brief summary

Laminectomy surgeries, typically performed for lumbar disc herniation and spinal disorders, are often lengthy surgical procedures requiring patients to be in the prone position. While this position provides better visibility of the surgical field, it can lead to physiological changes in intraocular pressure (IOP) in anesthetized patients. An increase in IOP, though rare, has the potential to cause severe ocular complications such as postoperative vision loss (POVL), which is one of the most feared complications after spinal surgery. One of the main mechanisms of IOP elevation in the prone position is the impediment of venous return in the head and neck region due to gravity, leading to an increase in episcleral venous pressure. Additionally, direct mechanical pressure on the face and globe can also increase IOP. Anesthesia management can also play a role in IOP dynamics by affecting intrathoracic pressure and venous return. This complex interaction necessitates careful monitoring of eye health in anesthetized patients in the prone position. Non-contact tonometers offer a non-invasive, rapid, and reliable method for IOP measurement. They are particularly advantageous for repeated measurements in anesthetized patients. This clinical study aims to evaluate changes in IOP using a non-contact tonometer in patients undergoing laminectomy in the prone position and to identify anesthesia- and patient-related factors influencing these changes. The data obtained will contribute to the development of anesthesia and positioning strategies aimed at reducing the risk of ocular complications.

Interventions

None listed

Study design

Observational model

COHORT

Time perspective

OTHER

Eligibility

Sex/Gender

ALL

Age

18 Years to 65 Years

Healthy volunteers

Inclusion criteria

* Patients scheduled for laminectomy surgery under general anesthesia Patients with ASA physical status I-II-III Patients who can cooperate postoperatively Patients without eye diseases or conditions affecting eye physiology (such as glaucoma) Patients who have not undergone eye surgery Patients who consent to participate in the study

Exclusion criteria

* Patients scheduled for laminectomy surgery but not receiving general anesthesia Patients with ASA physical status IV-V Patients who do not consent to participate in the study Patients who cannot cooperate postoperatively Patients with eye diseases or conditions affecting eye physiology (such as glaucoma) Patients who have undergone eye surgery Patients from whom consent cannot be obtained

Design outcomes

Primary

Measure	Time frame
Intraoperative IOP Measurement Schedule After Induction: Intraocular pressure (IOP) is measured non-contact using a tonometer. Intraoperative 1st Hour: After Prone Positioning:	half an hour

Outcome results