Ultrasound biomicroscopy as a tool for detecting and localizing occult foreign bodies after ocular trauma

ULTRASOUND BIOMICROSCOPY AND ECHOGENIC EXTERNAL MARKER ASSISTED INTRAOCULAR FOREIGN BODY REMOVAL

PURPOSE

We report a novel method of intraoperative localization of a retained anterior intraocular foreign body (IOFB), using a combination of ultrasound biomicrosopy and an insulated needle.

METHODS

A retrospective case report of a 56-year-old man who presented with a right eye IOFB.

RESULTS

On presentation, vision was decreased in the right eye to count fingers with a small subconjunctival hemorrhage, but no other signs of a penetrating laceration. Orbital CT revealed an IOFB, and the initial vitrectomy failed to retrieve the IOFB. Then, during the subsequent vitrectomy, using an ultrasound compatible needle and an ultrasound biomicrosopy, we were able to precisely locate and remove the small anterior IOFB.

CONCLUSION

Retained IOFBs can lead to severe irreversible vision loss if not promptly removed. Ancillary imaging modalities and localization techniques can help locate occult IOFBs in difficult cases.

Intraocular endoscopy in the management of ocular trauma: clinical settings and treatment outcomes at a tertiary eye care centre

PURPOSE

To report the application of endoscopy in the management of ocular trauma, describe the clinical settings and the treatment outcomes.

METHODS

Retrospective, consecutive, non-comparative case series at a tertiary eye care centre. Data recorded included aetiology of trauma, presenting vision, corneal condition at presentation, per-operative clinical findings during endoscopy, prognostication of the cases on table, final visual and anatomic outcome. Odds ratios for a favourable outcome were computed for various surgical indications.

RESULTS

The study included 58 eyes of 58 patients. Males constituted 82% of all cases. Mean age at presentation was 35.55 ± 18.9 years, median 31.5 years. Commonest corneal condition causing opaque media was corneal oedema (44.8%) followed by corneal laceration in 25.8%, repaired corneal laceration in 13.7% and scarred cornea in 12%. Commonest indication for surgery was retinal detachment (36.2%) followed by vitreous haemorrhage (29.3%), retained foreign body (13.7%) and combined detachment with haemorrhage in 10.3%. Of the 58 eyes, 17 eyes were deemed inoperable on endoscopic examination and 11 eyes were deemed to have poor prognosis. Of the fair prognosis (n = 30), 60% had final vision of 20/400 (p = 0.0001) compared to 10% before surgery and 13.33% had final vision of 20/40 (p = 0.03) as compared to nil in the pre-operative period. Odds ratio for a favourable visual outcome was best for the indication of vitreous haemorrhage (OR = 9, p = 0.0006).

CONCLUSION

Endoscopy in ocular trauma with opaque media provides adequate visualisation and allows for prognostication. In cases deemed to have prognosis, suitable intervention leads to globe and vision salvage.

Pterygium surgery combined with the removal of a missed occult iris foreign body detected incidentally during pterygium examination: a case report

Background

An occult foreign body may be retained in patient with small self-sealing wound and no decreased visual acuity without complete examination. Here we report a case of a retained occult ferrous iris foreign body detected incidentally during pterygium examination.

Case presentation

A 69-year-old man presented to our ophthalmology department because of foreign body sensation and persistent redness in both eyes for 2 years. In the left eye, a pterygium, paracentral corneal opacity and a vertically oval pupil were observed. Ultrasound biomicroscopy and gonioscopy revealed a retained metallic-like foreign body partially embedded in the inferior peripheral iris. Pterygium surgery and the removal of the retained iris foreign body were performed simultaneously. No recurrent pterygium or residual foreign body was found during follow-up.

Conclusions

A thorough history should be obtained and complete physical examination should be performed in patients with ocular self-sealing wounds to prevent missed intraocular foreign bodies, which may result in potential sight-threatening ocular complications.

Acute ocular pain during magnetic resonance imaging due to retained intraocular metallic foreign body: the role of ultrasonography and ultrasound biomicroscopy in diagnosis and management of this condition

PURPOSE

To report the case of a 65-year-old metalworker with no known history of ocular trauma, who suffered from intense ocular pain during magnetic resonance imaging (MRI) of the brain, due to a retained intraocular metallic foreign body (IOFB).

CASE REPORT

Meticulous ophthalmological examination was inconclusive. An IOFB was confirmed with X-ray scan, whereas its exact localization was enabled by means of ultrasonography and ultrasound biomicroscopy (UBM).

CONCLUSIONS

Despite appropriate screening protocols, MRI-related ocular complications might occur in the presence of a hidden metallic IOFB. Clinical detection of ocular foreign bodies can sometimes be challenging. Ultrasonography and UBM are valuable adjuncts for the accurate localization, especially of small or hidden particles.

Detection of pars plana rupture by ultrasound biomicroscopy after cannula dislodgement during cataract wound hydration

Ultrasound biomicroscopy (UBM) is a valuable diagnostic modality for imaging anterior ocular structures. Its utility has been well studied in anterior segment, lenticular, and pars plicata pathologies. However, imaging of the pars plana has been seldom described. We present the case of a 66-year-old woman referred for vitreous hemorrhage after expulsive cannula dislodgement into the posterior segment during wound hydration at the end of cataract surgery. B-scan ultrasonography initially detected a very anterior abnormality, but the resolution was insufficient for accurate diagnosis. Subsequent UBM clearly showed rupture of the pars plana and a mild cyclodialysis cleft. To our knowledge, this is the first report of a pars plana rupture detected by ultrasound, which expands the diagnostic capacities and indications for UBM.

Longitudinal Evaluation of Wound Healing after Penetrating Corneal Injury: Anterior Segment Optical Coherence Tomography Study

PURPOSE

Ocular imaging can enhance our understanding of wound healing. We report anterior segment optical coherence tomography (ASOCT) findings in penetrating corneal injury.

METHODS

Serial ASOCT was performed after repair of penetrating corneal injury. Internal aberrations of wound edges were labeled as "steps" or "gaps" on ASOCT images. The wound type was characterized as: type 1: continuous inner wound edge or step height ≤ 80 µm; type 2: step height > 80 µm; type 3: gap between wound edges; and type 4: intraocular tissue adherent to wound. Surgical outcomes of different wound types were compared.

RESULTS

50 consecutive patients were included (6 females, 44 males; mean age 33 ± 12 years). The average size of wound was 4.2 ± 2.6 mm (type 1, 8 eyes; type 2, 27 eyes; type 3, 12 eyes; type 4, 3 eyes). At the end of 3 months, 70% (n = 35) of the wounds were type 1. At the end of 6 months, all type 1 wounds had healed completely, whereas about half of type 2 (48.1%) and type 3 (50%) wounds had recovered to type 1 configuration. The wound type at baseline affected the height of step (p = 0.047) and corneal thickness at 6 months (p = 0.035).

CONCLUSIONS

ASOCT is a useful tool for monitoring wound healing in cases with penetrating corneal injury. Majority of the wound edges appose between 3 and 6 months after trauma. In our study, baseline wound configuration affected the healing pattern.

Visibility of Different Intraorbital Foreign Bodies Using Plain Radiography, Computed Tomography, Magnetic Resonance Imaging, and Cone-Beam Computed Tomography: An in Vitro Study

Purpose

The study sought to compare the usefulness of 4 imaging modalities in visualizing various intraorbital foreign bodies (IOFBs) in different sizes.

Methods

Six different materials including metal, wood, plastic, stone, glass. and graphite were cut in cylindrical shapes in 4 sizes (dimensions: 0.5, 1, 2, and 3 mm) and placed intraorbitally in the extraocular space of fresh sheep's head. Four skilled radiologists rated the visibility of the objects individually using plain radiography, spiral computed tomography (CT), magnetic resonance imaging (MRI), and cone-beam computed tomography (CBCT) in accordance with a previously described grading system.

Results

Excluding wood, all embedded foreign bodies were best visualized in CT and CBCT images with almost equal accuracies. Wood could only be detected using MRI, and then only when fragments were more than 2 mm in size. There were 3 false-positive MRI reports, suggesting air bubbles as wood IOFBs.

Conclusions

Because of lower cost and using less radiation in comparison with conventional CT, CBCT can be used as the initial imaging technique in cases with suspected IOFBs. Optimal imaging technique for wood IOFBs is yet to be defined.

Anterior segment imaging in glaucoma: An updated review

Anterior segment imaging allows for an objective method of visualizing the anterior segment angle. Two of the most commonly used devices for anterior segment imaging include the anterior segment optical coherence tomography (AS-OCT) and the ultrasound biomicroscopy (UBM). AS-OCT technology has several types, including time-domain, swept-source, and spectral-domain-based configurations. We performed a literature search on PubMed for articles containing the text “anterior segment OCT,” “ultrasound biomicroscopy,” and “anterior segment imaging” since 2004, with some pertinent references before 2004 included for completeness. This review compares the advantages and disadvantages of AS-OCT and UBM, and summarizes the most recent literature regarding the importance of these devices in glaucoma diagnosis and management. These devices not only aid in visualization of the angle, but also have important postsurgical applications in bleb and tube imaging.

Intraocular foreign bodies: A review

Intraocular foreign body injuries may result in a wide range of intraocular pathology and visual outcomes based on the mechanism of injury, type of foreign body, and subsequent complications. We have reviewed the literature to describe the epidemiology and mechanisms of such injuries; types of foreign bodies; imaging tools for diagnosis; current trends in management, presurgical, and surgical interventions; as well as visual prognosis and potential complications. The purpose of this review is to familiarize clinicians with the recent advances in diagnosis and management of such injuries.

Observing implantable collamer lens dislocation by panoramic ultrasound biomicroscopy

PURPOSE

Observe the image characteristics and dislocation of implantable collamer lenses (ICL) following their use to correct high myopia.

METHODS

A total of 127 patients (242 eyes); 64 females (50.3%) and 63 males (49.7%) were included in this retrospective study with ICL V4 implantation and mean spherical equivalent -9.08±2.04 diopters (D). Panoramic ultrasound biomicroscopy (UBM) was utilized to observe anterior segment morphology and ICL location at various follow-up periods (1 week preoperative, followed by 1, 3, 6, and yearly postoperative).

RESULTS

Twenty-eight ICL eyes (11.2%) were noted to have abnormal postoperative positioning. The central vault of 12 eyes was too high with ICL decentration, mean central vault 1.14±0.39 mm; 10 eyes were too low but without ICL decentration, mean central vault 0.13±0.11 mm. The remaining subjects were only ICL decentration without abnormal central vault, mean central vault was 0.54±0.28 mm.

CONCLUSIONS

This study shows the abnormal characteristics regarding ICL locations. The ICL dislocation closely correlates with the central vault. The ICL dislocation is the primary cause of several postoperative complications. Panoramic UBM is one of the most effective imaging means to observe the ICL positioning and its stability after implantable surgery.

Anterior segment imaging in combat ocular trauma

Purpose. To evaluate the use of ocular imaging to enhance management and diagnosis of war-related anterior segment ocular injuries. Methods. This study was a prospective observational case series from an ongoing IRB-approved combat ocular trauma tracking study. Subjects with anterior segment ocular injury were imaged, when possible, using anterior segment optical coherence tomography (AS-OCT), confocal microscopy (CM), and slit lamp biomicroscopy. Results. Images captured from participants with combat ocular trauma on different systems provided comprehensive and alternate views of anterior segment injury to investigators. Conclusion. In combat-related trauma of the anterior segment, adjunct image acquisition enhances slit lamp examination and enables real time In vivo observation of the cornea facilitating injury characterization, progression, and management.

[Intraocular foreign bodies (IOFB) of the posterior segment: retrospective analysis and management of 57 cases]

PURPOSE

To determine the influence of prognostic factors and the type of tamponade agent in surgical management of intraocular foreign bodies (IOFBs) for better visual outcome.

PATIENTS AND METHODS

Fifty-seven consecutive cases were retrospectively reviewed at the XV-XX National Hospital (Paris) between 1 January 2004 and 31 December 2007. Univariate and multivariate analyses were performed to identify prognostic variables. Several parameters were measured: pre- and postoperatively: best corrected visual acuity (BCVA), material and size of the foreign body, entry site, time from trauma to surgical removal, IOFB location, initial retinal detachment, choice of vitreous tamponade agent (none, gas, silicone oil), postoperative visual outcome, and complications (siderosis, endophthalmitis, and vitreoproliferative retinal detachment).

RESULTS

Metal IOFBs accounted for the majority with 80.7% (n=46). The inferior retinal segment was the most frequent location found: 47.4% (n=27). Initial and final mean BCVAs were, respectively, 1.47 (±0.99) and 1.03 (±0.96) (LogMar scale). The mean follow-up was 20.7 months (range, 12-60 months). Initial retinal detachment was found in 24.56% (n=14), with a statically worse prognosis. The BCVA was better in the group with gas tamponade (n=16) than in the group with silicone tamponade (n=21) and the group without a tamponade agent (n=20). Initial BCVA was the most important predictive factor for final BCVA. Time to surgery was a predictive factor of final visual outcome with a cut-off in the first week. The scleral or corneoscleral entry site had a better prognosis than the corneal site. Five cases of siderosis (8.7%) related to delayed management and two cases of endophthalmitis (3.5%) were found (despite use of prophylactic systemic antibiotics). No statistical difference was found regarding the IOFB location on the retina, its size, or the material. Finally, the retina remained detached in nine cases (15.78%). A final BCVA of 20/40 or more was obtained in 39.3 and 17.5% had light perception or worse.

CONCLUSION

The prognosis of an IOFB injury is for the most part uncertain due to a complex combination of parameters. Nevertheless, good postoperative results can be achieved without a silicone tamponade agent. The main prognostic factors related to better visual outcome were initial BCVA, time to surgery (first week), initially attached retina, and the scleral entry site. The main complications were vitreoproliferative retinal detachment, endophthalmitis, and siderosis. The location, type, and size of IOFBs were not statistically significant predictive factors in this study.

Ultrasonic evaluation of pupillary light reflex

Background

Evaluation of pupillary light reflex (PLR) is an important neurological test with a variety of clinical applications. Obstacles such as severe soft tissue damage or hyphema may obstruct the visual access to the pupil, thus rendering direct PLR observation difficult or impossible. Multipurpose ultrasonic systems, however, can overcome this problem.

Methods

Using ultrasound imaging, a coronal view of the iris and pupil allowed visualization of PLR upon contralateral stimulation with a penlight. The technique was tested in ten healthy volunteers and a trauma case study.

Results

Satisfactory visualization of the iris was achieved in all subjects, in an average time of 1 min 10 s. Temporal parameters of pupillary constriction, oscillations (hippos) and relaxation could also be measured on M-mode displays.

Conclusions

Real-time coronal imaging of the iris using multipurpose ultrasound imaging is found to be a practical, fast and recordable method that can be used for evaluating PLR.

Occult open globe injury in a patient with corneal foreign body: a case report

PURPOSE

To demonstrate the role of ultrasonographic biomicroscopy in diagnosing occult open globe injury.

METHOD

A 50-year old man presented with a 2-day history of a corneal foreign body caused by a missile injury. Slit lamp biomicroscopy showed an intrastromal corneal foreign body measuring 0.7 x 0.7 mm, situated at the visual axis. Seidel test was negative. Full thickness corneal penetration could not be ruled out and an ultrasonographic biomicroscopy examination was subsequently performed.

RESULTS

Ultrasonographic biomicroscopy revealed a probable full thickness corneal penetration. The patient was diagnosed with penetrating corneal injury.

CONCLUSION

Ultrasonographic biomicroscopy has an important role in the diagnosis of occult open globe injury.

Occult intraocular foreign body: ultrasound biomicroscopy holds the key

PURPOSE

To illustrate the successful management of an occult intraocular foreign body (IOFB) lodged posterior to the iris causing persistent endophthalmitis.

METHODS

Two young male patients presented with corneal laceration, endophthalmitis and foreign body on X-ray but not localized by B-scan ultrasonography or gonioscopy.

RESULTS

Ultrasound Biomicroscopy (UBM) localized the foreign body lodged between the posterior iris and anterior lens surface accurately, which was successfully removed through the limbus using an external magnet.

CONCLUSIONS

UBM is invaluable to accurately localize occult IOFBs lodged in the posterior iris or ciliary body region, which ensures good visual rehabilitation of these hitherto considered difficult cases.

High-frequency ultrasonic imaging of the anterior segment using an annular array transducer

OBJECTIVE

Very high-frequency ultrasound (VHFU; >35 megahertz [MHz]) allows imaging of anterior segment structures of the eye with a resolution of less than 40 microm. The low focal ratio of VHFU transducers, however, results in a depth of field (DOF) of less than 1 mm. The aim was to develop a high-frequency annular array transducer for ocular imaging with improved DOF, sensitivity, and resolution compared with conventional transducers.

DESIGN

Experimental study.

PARTICIPANTS

Cadaver eyes, ex vivo cow eyes, in vivo rabbit eyes.

METHODS

A spherically curved annular array ultrasound transducer was fabricated. The array consisted of 5 concentric rings of equal area, had an overall aperture of 6 mm, and a geometric focus of 12 mm. The nominal center frequency of all array elements was 40 MHz. An experimental system was designed in which a single array element was pulsed and echo data were recorded from all elements. By sequentially pulsing each element, echo data were acquired for all 25 transmit-and-receive annuli combinations. The echo data then were focused synthetically and composite images were produced. Transducer operation was tested by scanning a test object consisting of a series of 25-microm diameter wires spaced at increasing range from the transducer. Imaging capabilities of the annular array were demonstrated in ex vivo bovine, in vivo rabbit, and human cadaver eyes.

MAIN OUTCOME MEASURES

Depth of field, resolution, and sensitivity.

RESULTS

The wire scans verified the operation of the array and demonstrated a 6.0-mm DOF, compared with the 1.0-mm DOF of a conventional single-element transducer of comparable frequency, aperture, and focal length. B-mode images of ex vivo bovine, in vivo rabbit, and cadaver eyes showed that although the single-element transducer had high sensitivity and resolution within 1 to 2 mm of its focus, the array with synthetic focusing maintained this quality over a 6-mm DOF.

CONCLUSIONS

An annular array for high-resolution ocular imaging has been demonstrated. This technology offers improved DOF, sensitivity, and lateral resolution compared with single-element fixed focus transducers currently used for VHFU imaging of the eye.

Excimer Laser Phototherapeutic Keratectomy

Anterior corneal pathology, such as corneal scars and corneal stromal dystrophies, can be visually devastating. Over the past decade, there was a shift in treatment of these conditions from corneal transplantation to phototherapeutic keratectomy (PTK) using the 193 nm excimer laser for visual restoration. We have reviewed the recent literature on techniques for performing and refining PTK and also on various pathologic conditions that can be treated with PTK. The primary indications for PTK include anterior corneal dystrophies, such as lattice, granular, and Reis-Bückler's dystrophy. PTK can produce significant visual improvement in these patients, and corneal transplantation or retransplantation can be delayed. Corneal degenerations, such as Salzmann's nodular degeneration, keratoconus nodules, and climatic droplet keratopathy, also can be successfully treated with PTK. Additionally, anterior corneal scars from such etiologies as trauma, corneal ulcers, and prior refractive surgery can have visual improvement with PTK. In summary, PTK is a powerful tool for the management of anterior corneal pathology. In a properly selected and well-counseled patient, PTK can significantly improve vision and quality of life.

Role of Ultrasound Biomicroscopy (UBM) in the Detection and Localisation of Anterior Segment Foreign Bodies

Introduction: The aim of this study was to investigate the role of ultrasound biomicroscopy (UBM) in imaging anterior segment foreign bodies and compare it with conventional B-scan ultrasound and computed tomography (CT). Materials and Methods: The charts of 18 eyes with anterior segment foreign bodies were reviewed. The rates of detection of foreign bodies using ultrasound, CT scan and UBM were compared. Results: The foreign body detection rates were 36.5% by ultrasound, 88.9% by CT scan, and 94.4% by UBM. The diagnosis of presence of a foreign body using UBM was made based on high reflective echoes causing shadowing or reverberations. In 7 eyes, UBM detected injury to the zonules, guiding the operative procedure. In the 8 eyes for which all tests were performed, rates of detection of foreign bodies were 25% (2/8) with ultrasound, 87.5% (7/8) with CT, and 100% (8/8) with UBM. Conclusion: UBM is a valuable adjunct for the accurate localisation of small foreign bodies, including cilia. It offers a higher detection rate than that provided by ultrasound and CT scan. Key words: B-scan ultrasonography, Computed tomography, Ocular trauma, Retained foreign bodies

Intralenticular intraocular foreign body after stone impact: CT and US findings

INTRODUCTION

Intraocular foreign body (IOFB) is a relatively common entity in emergency departments worldwide. Appropriate ocular assessment is mandatory if an intraocular foreign body is suspected because it is associated with an increased risk of endophtalmitis and a wide range of complications including hyphaema, cataract, vitreous hemorrhage, and retinal tears and detachment.

CASE REPORT

We present a case of intralenticular intraocular foreign body after stone impact.

DISCUSSION

Ultrasonography (US) and computed tomography (CT) show an accurate location of the foreign body inside the lens. This finding enabled the surgeon to perform a phacoemulsification lens extraction with removal of the foreign body, the optimal method of removing intralenticular IOFB. To our knowledge, this is the first US and CT imaging report.

Detection of metallic ocular foreign bodies with handheld sonography in a porcine model

OBJECTIVE

Eye conditions are common in emergency departments. Intraocular foreign bodies (IOFBs) are a frequent concern. Orbital computed tomography (CT) is traditionally used for evaluation. We sought to evaluate bedside ocular sonography for detecting metallic IOFBs.

METHODS

A pig model was chosen. A micrometer was used to create 3 precise metallic fragments: 0.012 x 0.012 x 0.012, 0.025 x 0.025 x 0.012, and 0.05 x 0.05 x 0.012 in. Individual eyes were randomized to the presence or absence of a foreign body. Randomization was also used to determine the specific size of any given IOFB. A standard 18-gauge spinal needle was used to puncture the sclera and introduce the IOFB into the vitreous. Each eye was then evaluated by 2 sonologists for the presence or absence of an IOFB.

RESULTS

A total of 28 eyes were used; 12 (43%) were randomized to no IOFB and 16 (57%) to the presence of an IOFB. Of the 16 eyes that received IOFBs, 8 (50%) were 0.012 x 0.012 x 0.012 in; 5 (31%) were 0.025 x 0.025 x 0.012 in; and 3 (19%) were 0.05 x 0.05 x 0.012 in. Sensitivity was 87.5% and specificity 95.8%. Positive predictive value (PPV) and negative predictive value (NPV) were 96.5% and 85.2%, respectively.

CONCLUSIONS

Bedside sonography may identify the presence of metallic IOFBs. The PPV allows a high degree of certainty that an IOFB is actually present if seen and may negate the need for uninfused orbital CT. The NPV was 85.2%. Given the potential grave consequences of a missed IOFB, sonography cannot be used as the definitive test to rule out the presence of a metallic IOFB. In the presence of negative findings, further imaging is warranted.

Unusual cause for non-detection of retained metallic foreign body on ocular ultrasonography

Ultrasound biomicroscopy has become a valuable adjunct in the evaluation of occult ocular foreign bodies. An unusual cause for non-detection of a metallic retained intraocular foreign body is described. In this case, the usual 'shadowing' was not discernible as the foreign body was lying just over the optic disc.

Excimer laser phototherapeutic keratectomy in eyes with anterior corneal dystrophies: short-term clinical outcomes with and without an antihyperopia treatment and poor effectiveness of ultrasound biomicroscopic evaluation

PURPOSE

To evaluate the use of high-frequency ultrasound biomicroscopy (UBM) in determining the depth of corneal pathology in eyes undergoing excimer laser phototherapeutic keratectomy (PTK) for primary or recurrent anterior stromal corneal dystrophies. Corneal clarity, visual acuity, and refractive changes in eyes with and without an antihyperopia treatment were also analyzed.

METHODS

Twenty eyes of 14 patients with anterior stromal corneal dystrophies were treated with PTK. Eyes were evaluated pre- and 6-8 weeks postoperatively with slit-lamp biomicroscopy, manifest refraction, keratometry, computerized corneal topography, ultrasound pachymetry, and UBM.

RESULTS

Nineteen of 20 corneas (95%) had greatly improved corneal clarity after PTK. Mean uncorrected Snellen vision improved from 20/102 to 20/69, and best corrected vision improved from 20/62 to 20/38. Nine eyes (45%) improved two or more lines of uncorrected vision, and 13 eyes (65%) improved two or more lines of best corrected vision. Mean change in spherical equivalent was just -0.92 diopters (SD 4.3 diopters); however, the range was large (-13 to +3.88 diopters). UBM measurement of central corneal pathology did not correlate significantly with the actual PTK ablation depth (P = 0.07). The amount of antihyperopia treatment did not correlate with changes in manifest refraction spherical equivalent, keratometry, or computerized corneal topography readings but did correlate with length of time until corneal reepithelialization after PTK (P = 0.003).

CONCLUSIONS

PTK resulted in improvements in corneal clarity and visual acuity in most patients with superficial corneal stromal dystrophies. UBM was not an effective tool to accurately measure the depth of corneal pathology preoperatively. The combined approach of minimizing ablation depth and selective use of an antihyperopia treatment resulted in minimal mean change in spherical equivalent; however, the range was large. PTK is a very good minimally invasive technique to improve vision in eyes with anterior stromal corneal dystrophies.

Ultrasound biomicroscopic evaluation of the traumatized eyes

PURPOSE

To review causes for performing an ultrasound biomicroscopic (UBM) examination in traumatized eyes, to present common UBM findings of 109 eyes with a history of ocular trauma and to compare these findings according to the type of the trauma.

MATERIALS AND METHODS

A total of 109 eyes with a history of mechanical ocular trauma, which underwent an UBM examination between December 1996 and April 2002, were evaluated retrospectively. All cases were classified according to the criteria of the Ocular Trauma Classification Group and UBM findings were reviewed. For statistical ana- lyses, chi(2) test and Fisher's exact test were used.

RESULTS

UBM examinations were performed for the evaluation of the zonules before cataract surgery (49.5%), examination of the anterior segment in the presence of media opacities (32.1%), detection of suspected ocular foreign bodies (10.1%) and the evaluation of ocular hypotony (8.3%). In all, 67 eyes (61.5%) had a closed-globe injury, whereas 42 (38.5%) had an open-globe injury. The most common UBM findings in a closed-globe injury were zonular deficiency (64.2%), angle recession (43.3%), iridodialysis (17.9%), and dislocated lens (16.4%). The most common UBM findings in an open-globe injury were zonular deficiency (54.8%), iridodialysis (26.2%), peripheral anterior synechiae (PAS) (26.2%), and iridocorneal adhesion (19%). Among the common UBM findings, the angle recession was significantly higher (P<0.001) in closed-globe injury group and PAS formation was significantly higher (P<0.05) in open-globe injury group.

CONCLUSIONS

UBM is particularly superior to other methods in the evaluation of the zonular status, angle recession, cyclodialysis, and the detection of small superficial and intraocular foreign bodies.

Evaluation of the ultrasound biomicroscope in strabismus surgery

PURPOSE

This study was done to determine the ability of the ultrasound biomicroscope (UBM) to define the distance of the horizontal extraocular muscle insertions from the limbus in children undergoing strabismus surgery.

METHODS

A total of 51 children undergoing primary surgery on their horizontal muscles were recruited for this study. The 50 MHz UBM was used before surgery on the muscle(s) requiring an operation to define the distance of the insertion of the horizontal rectus muscle(s) from the limbus. These data were stored on a computer and masked from the surgeon who measured the actual insertion from the limbus with calipers intraoperatively. An intraclass correlation coefficient was calculated to determine the correlation of the UBM measurement with that performed during surgery.

RESULTS

Measurement of the distance of the insertions from the limbus were taken on 79 muscles of the 51 patients: 44 medial rectus (MR) and 35 lateral rectus (LR). Mean age of the patients was 6.4 +/- 3.7 years (range, 1-15). A total of 29 children (56.9%) were female. The mean distance of MR from the limbus measured surgically was 5.2 +/- 0.6 mm (range, 4-6 mm; median, 5 mm) and measured with the UBM was 5.2 +/- 0.9 mm (range, 4-7.6 mm; median, 5.3 mm). Comparable results for the LR muscles were 6.4 +/- 0.6 mm (range, 5.5-7.5 mm; median, 6.5 mm) and 6.9 +/- 0.7 mm (range, 5.9-8.4 mm; median, 6.9 mm), respectively. An intraclass correlation coefficient of 0.71 signified good agreement between the surgical and UBM measurements of the distance from the limbus of the horizontal rectus muscle insertions.

CONCLUSION

The UBM could be used reliably as a tool before surgery to estimate the distance of the horizontal rectus muscles from the limbus in children with strabismus.

Radiologic differentiation of intraocular glass: evaluation of imaging techniques, glass types, size, and effect of intraocular hemorrhage

OBJECTIVE

The accurate detection of intraocular foreign bodies is critically important in treating ocular trauma. The purpose of this study was to evaluate the efficacy of CT, MR imaging, and sonography in detecting seven types of glass varying in size and placed in three locations in the globe, and to examine the effect of intraocular hemorrhage.

MATERIALS AND METHODS

Glass pieces were cut into 1.5-, 1.0-, and 0.5-mm pieces and implanted on the corneal surface and the anterior and posterior chambers of 42 fresh porcine eyes. Twenty-one eyes were scanned comparing axial CT, helical CT, and MR imaging. The remaining 21 eyes were scanned using helical CT and sonography after implantation in a simulated human skull before and after placement of blood in the anterior chamber (hyphema).

RESULTS

Detection rates were 57.1% for helical CT, 41.3% for axial CT, and 11.1% for T1-weighted MR imaging (n = 63 fragments). Results were significant (p < 0.0001). Sonography detected 43% of glass fragments in the posterior chamber and 24% in the anterior chamber. Detectability was greatest for green beer bottle glass (90.3%) and least for spectacle glass (43.1%) (p < 0.0001). Detection rates for size ranged from 96.2% at 1.5 mm to 48.3% at 0.5 mm, which was also significant (p < 0.0001). On helical CT, anterior chamber glass was easiest to detect (91.7%) and corneal surface glass the most difficult (64.9%). Hyphema made no statistical difference (p < 0.0001).

CONCLUSION

Helical CT was the most sensitive imaging modality for the detection of intraocular glass. The sensitivity of detection was unaffected by hyphema but was determined by the type of glass, size, and location.

Ultrasound biomicroscopy of the aging rhesus monkey ciliary region

Ultrasound biomicroscopy of the living rhesus monkey ocular ciliary region was undertaken to identify age-dependent changes that might relate to the progression of presbyopia. Monkeys were anesthetized and pharmacologically cyclopleged, the eyelids were held open with a lid speculum, and sutures were placed beneath the medial and lateral rectus muscles. Ultrasound biomicroscopy imaging of the nasal and temporal quadrants of the eye were performed, and the live images were recorded to videotape. Subsequent image analysis was performed to obtain objective morphometric measurements of the ciliary body region. The ciliary body inner radius of curvature, outer radius of curvature, inner arc length, area, thickness, perimeter, zonular fiber length, and circumlental space were measured. Zonular space was calculated. The circumlental space decreased with increasing age in the temporal quadrant. The other morphologic measurements were not significantly correlated with age or body weight. Most morphologic measurements were significantly different comparing temporal vs. nasal quadrants. Bifurcation of the posterior zonular fibers was frequently observed. Although temporal circumlental space was the only measurement found to change with age, ultrasound biomicroscopy of the living rhesus ciliary region did identify distinct nasal vs. temporal asymmetries, which may reflect anatomical requirements for convergence-associated accommodation.

Ultrasound biomicroscopy in the diagnosis and management of pars planitis caused by caterpillar hairs

PURPOSE

To report the use of ultrasound biomicroscopy in the detection of caterpillar hairs in the pars plana in a patient with unilateral pars planitis.

METHOD

Ultrasound biomicroscopic imaging of the anterior segment of the eye.

RESULTS

Ultrasound biomicroscopy located a hair in the posterior chamber at the first visit and five more in the pars plana 1 month later. This finding was confirmed intraoperatively.

CONCLUSION

Ultrasound biomicroscopy is useful in the diagnosis and management of unilateral pars planitis of uncertain cause.

Orbital helical computed tomography in the diagnosis and management of eye trauma

OBJECTIVE

To prospectively determine the accuracy of helical computed tomography (CT) and multiplanar reconstruction and its value in surgical planning for the management of ocular trauma with suspected intraocular and orbital foreign bodies using surgical and clinical follow-up findings as the gold standard.

DESIGN

Prospective, observational case series.

PARTICIPANTS

Thirty-six patients with ocular trauma and suspected foreign bodies were studied.

INTERVENTION

All patients were examined using a standardized scanning protocol with helical CT direct scanning in the axial plane and multiplanar reconstruction of coronal and sagittal planes.

MAIN OUTCOME MEASURES

The images were analyzed for the presence and number of intraocular and orbital foreign bodies, anatomic location, and foreign body size. The surgical and clinical follow-up findings (contact lens examination, gonioscopy, indirect ophthalmoscopy and scleral depression, perimetry, color testing, measurement of size) were used as the gold standard to which the image results were compared.

RESULTS

Helical CT showed a single intraocular foreign body in 14 patients, a single orbital foreign body in 9 patients, and multiple orbital foreign bodies in 2 patients. Intraocular or orbital foreign bodies were excluded in 11 patients. Twenty foreign bodies were correlated with surgical results. Surgical and clinical follow-up findings were in agreement with helical CT results regarding the detection and determination of the number of presumed foreign bodies. Localization to intraocular versus orbital compartment and proximity to the optic nerve was accurate in all patients. Determination of size of the foreign bodies on the helical CT images was reliable and repeatable.

CONCLUSIONS

Helical CT axial scanning with multiplanar reconstruction is accurate at detecting and localizing intraocular and orbital metallic, glass, and stone foreign bodies. This imaging method aids the surgeon in choosing the surgical approach to retained intraocular and orbital foreign bodies.