Visual outcomes after traumatic retrobulbar hemorrhage are not related to time or intraocular pressure

The Repeatability and Reproducibility of a New Minimally Invasive Method for Orbital Pressure Measurement

BACKGROUND

Evaluation of orbital pressure is crucial for monitoring various orbital disorders. However, there is currently no reliable technique to accurately measure direct orbital pressure (DOP). This study aimed to establish a new method for the DOP as well as to verify its repeatability and reproducibility in rabbits.

METHODS

The study included 30 normal eyes from fifteen 3-month-old New Zealand white rabbits. After administering inhalation anesthesia, intraocular pressure (IOP) was determined by tonometry (Tonopen). For DOP manometry, a TSD104 pressure transducer was inserted between the disposable injection needle and the syringe, and the output results were displayed on a computer. Two observers independently participated in the experiment to verify its repeatability and reproducibility.

RESULTS

The mean IOP of rabbits was significantly higher than the DOP in normal rabbits (11.67 ± 1.08 mm Hg versus 4.91 ± 0.86 mm Hg, P < 0.001). No significant interocular difference was detected for both IOP and DOP ( P > 0.05). A high correlation was found for intraobserver measurements of both IOP (intraclass correlation coefficient = 0.87, P < 0.001) and DOP (intraclass correlation coefficient = 0.89, P < 0.001). A high agreement was also presented for the interobserver reproducibility for the measurements of IOP [Pearson correlation coefficient ( R ) = 0.86, P < 0.001] and DOP ( R = 0.87, P < 0.001). Direct orbital pressure was positively correlated with IOP in both observers ( R 1 = 0.66, R 2 = 0.62, P < 0.001). The Bland-Altman plots revealed that 5.0% (3/60) of the IOP and DOP measurement points were outside of the 95% limits of agreement, respectively.

CONCLUSIONS

The TSD104 pressure transducer-based manometry may serve as a reliable device for the measurement of DOP, providing real-time measuring results with acceptable reproducibility and repeatability.

[Optic nerve decompression-state of the art]

Rarely, but often with serious consequences for the patient, the optic nerve is affected during the course of head injuries. Traumatic optic nerve compression is always an emergency situation, which is why time is of the essence for both diagnosis and treatment. Precise knowledge of this accident sequelae but also of the resulting conditions, especially in terms of traumatic optic neuropathy, is indispensable for adequate patient care. The aim of this paper is to provide an overview of this clinical picture, particularly with regard to etiology, diagnosis, and treatment options, and to discuss this in the context of the current literature.

Assessment of Orbital Compartment Pressure: A Comprehensive Review

The orbit is a closed compartment defined by the orbital bones and the orbital septum. Some diseases of the orbit and the optic nerve are associated with an increased orbital compartment pressure (OCP), e.g., retrobulbar hemorrhage or thyroid eye disease. Our aim was to review the literature on the different approaches to assess OCP. Historically, an assessment of the tissue resistance provoked by the retropulsion of the eye bulb was the method of choice for estimating OCP, either by digital palpation or with specifically designed devices. We found a total of 20 articles reporting direct OCP measurement in animals, cadavers and humans. In nine studies, OCP was directly measured in humans, of which five used a minimally invasive approach. Two groups used experimental/custom devices, whilst the others applied commercially available devices commonly used for monitoring the compartment syndromes of the limbs. None of the nine articles on direct OCP measurements in humans reported complications. Today, OCP is mainly estimated using clinical findings considered surrogates, e.g., elevated intraocular pressure or proptosis. These diagnostic markers appear to reliably indicate elevated OCP. However, particularly minimally invasive approaches show promises for direct OCP measurements. In the future, more sophisticated, specifically designed equipment might allow for even better and safer measurements and hence facilitate the diagnosis and monitoring of orbital diseases.

Minimally invasive measurement of orbital compartment pressure and implications for orbital compartment syndrome: a pilot study

BACKGROUND

Diagnosis of orbital compartment syndrome is mainly based on clinical findings, such as intraocular pressure and proptosis, which try to estimate the orbital compartment pressure. However, the reliability of these surrogates is unclear. Current techniques for the direct measurement of orbital compartment pressure are widely experimental and impractical in the clinical setting. Our aim was to explore the feasibility of minimally invasive needle manometry for direct measurement of orbital compartment pressure under reproducible conditions in an in vivo model of orbital congestion. We further sought to evaluate intraocular pressure and proptosis as indicators for elevated orbital compartment pressure.

METHODS

A total of 7 ml of mepivacaine 2% solution was injected into the orbital compartment in 20 patients undergoing cataract surgery under local anesthesia. A commercially available single-use manometer device was inserted between the syringe and the injection needle to measure the orbital compartment pressure for each milliliter of intraorbital volume increment. Additionally, intraocular pressure (subgroup A; n = 10) or axial globe position (subgroup B; n = 10) were measured.

RESULTS

Needle manometry allowed for rapid and continuous measurement of orbital compartment pressure. Overall mean orbital compartment pressure increased from 2.5 mmHg pre- to 12.8 mmHg post-interventionally. Both, intraocular pressure (Spearman's correlation coefficient rs = 0.637, p < 0.0001) and proptosis (rs = 0.675, p < 0.0001) correlated strongly with the orbital compartment pressure.

CONCLUSIONS

Needle manometry appears to be a feasible minimally invasive instrument to directly measure orbital compartment pressure, showing promises for a more routine application in managing orbital compartment syndrome. The results further suggest that both elevated intraocular pressure and proptosis are valuable indicators for orbital compartment syndrome.

Volumetric Analysis and Clinical Outcome in 54 Patients with Retrobulbar Hematoma

PURPOSE

Retrobulbar hematoma (RBH) is a rare but serious vision threatening emergency. We analyze the relationship between hematoma volume, visual impairment and outcome.

METHODS

Fifty-four patients with RBH receiving orbital decompression were retrospectively included. Volumetric analysis of RBH was performed by semi-automatic segmentation based on preoperative CT scans using ITK-SNAP software. Best corrected visual acuity (BCVA) measurements were obtained and correlated in 2 groups (no light perception (NLP), severe visual impairment) with the hematoma volume.

RESULTS

NLP was documented preoperatively in 5/28 and postoperatively in 9/43 patients. Preoperative NLP was significantly associated with a larger hematoma volume (P = .03) and higher hematoma/orbital volume ratio (P = .03). Postoperative severe visual impairment showed significant associations with a larger hematoma volume (P = .02) as well as higher hematoma/orbital volume ratio (P = .02).

CONCLUSION

Eyes with severe visual impairment and large hematoma volumes preoperatively are at high risk of permanent vision loss. Hematoma volume calculation might represent an additional prognostic parameter for visual outcome after RBH.

Orbital compartment syndrome: Pearls and pitfalls for the emergency physician

Orbital compartment syndrome (OCS) is a rare, vision-threatening diagnosis that requires rapid identification and immediate treatment for preservation of vision. Because of the time-sensitive nature of this condition, the emergency physician plays a critical role in the diagnosis and management of OCS, which is often caused by traumatic retrobulbar hemorrhage. In this review, we outline pearls and pitfalls for the identification and treatment of OCS, highlighting lateral canthotomy and inferior cantholysis (LCIC), a crucial skill for the emergency physician. We recommend adequate preparation for the diagnosis and procedure, early consultation to ophthalmology, clear and thorough documentation of the physical examination, avoidance of iatrogenic injury during LCIC, and complete division of the inferior canthal tendon. Emergency physicians should avoid failing to make the diagnosis of OCS, delaying definitive surgical treatment, overrelying on imaging, failing to decrease intraocular pressure, and failing to exclude globe rupture. The emergency physician should be appropriately trained to identify signs and symptoms of OCS and perform LCIC in a timely manner.