Glaucoma, Glaucoma Following Surgery
Conditions
Keywords
optical coherence tomography
Brief summary
Trabeculectomy is a very important and commonly performed glaucoma operation. It allows fluid from inside the eye to exit into a space called a bleb located on the surface of the eye under the upper eyelid. The formation of excessive scar tissue after surgery may cause the operation to work less well or stop working. This results in an increase in eye pressure. The use of a needle to cut the scar tissue is a commonly used procedure. This surgery is called trans-conjunctival needle revision (TCNR) of trabeculectomy bleb. The study aims to determine if advanced optical imaging called Optical Coherence Tomography (OCT) of the scar tissue both in the office prior to surgery and during surgery in the operating room improves the success rate of the revision surgery. These devices are FDA approved and have been used extensively in ophthalmology and ocular surgery. Ophthalmologists already used these imaging devices for this purpose as part of the standard medical care of some patients. The purpose of this study is to prospectively gather information about its use in a systematic way. Furthermore, investigators want to determine if imaging improves outcomes compared to historical controls (patients who underwent the same surgery in the past without imaging). The potential benefit of this research is that it may provide knowledge that will be of benefit to future patients with glaucoma who are undergoing this procedure.
Detailed description
Trabeculectomy is one of the most commonly performed glaucoma procedures performed to control IOP with approximately 18,000 operations performed in US Medicare beneficiaries alone in 2012. One complication of trabeculectomy surgery is the formation of subconjunctival and episcleral fibrosis, which occurs as part of the wound healing process and can result in fibrosis of the filtering bleb and failure. Transconjunctival needle revision (TCNR) aims to lyse subconjunctival adhesions and reestablish adequate aqueous humor flow from the anterior chamber to the subconjunctival space. One study reported 17% of trabeculectomies require bleb-needling revision. During TCNR the surgeon is able to visualize the trajectory of the needle or blade under the conjunctiva; however, detection of the fibrotic tissue and determination as to whether that tissue has been adequately lysed is difficult, limiting the success rate of the procedure. Anterior segment optical coherence tomography (AS-OCT) allows for detailed assessment of the internal morphology of the bleb. Studies have utilized AS-OCT to assess morphological features of the bleb and correlate it with surgical success. A small case series reported the utility of AS-OCT for pre-operative planning for bleb revision, in particular, identifying safe access sites and minimizing conjunctival dissection. More recently, real time OCT integrated with operative microscope has become available. Intraoperative OCT (iOCT) has been utilized extensively in retinal surgery and corneal surgery. Dada et al., described performing iOCT-guided TCNR in 2 patients with failed trabeculectomy blebs without intraoperative or postoperative complications. Investigators reported they were able to obtain a detailed view of the bleb wall and assess the depth and location of the needle, which permitted better lysis of adhesions. A pilot study by Kumar et al., reported one case of TCNR in which iOCT was used to demonstrate the extent of adhesions and loculations inside the bleb at the beginning of the procedure, and the lysis of these adhesions and formation of large single hyporeflective cavity inside the bleb at the end of the procedure. These small case studies suggest a role of iOCT imaging for TCNR, however, further research is needed to assess its feasibility and utility for routine use. The aim of the research is to assess the surgical success, feasibility and utility of pre-operative Anterior Segment Optical Coherence Tomography (AS-OCT) and intraoperative Optical Coherence Tomography (iOCT) in trans-conjunctival needle revision (TCNR) of trabeculectomy bleb. Furthermore, investigators want to assess whether AS-OCT can be used to identify characteristics of trabeculectomy blebs that are associated with successful surgical outcomes. To undergo this study, investigators will conduct a prospective study of patients who consent to AS-OCT and iOCT revision of TCNR. Investigators will compare the outcomes of these patients with retrospectively identified, historical controls (i.e. patients who underwent TCNR by the same surgeon without AS-OCT or iOCT assistance). investigators hypothesize that information gained from pre-operative AS-OCT and intraoperative OCT will aid with intraoperative decision-making for TCNR of trabeculectomy bleb and will thereby improve surgical outcomes. Investigators also hypothesize that preoperative AS-OCT can be used to identify features of trabeculectomy bleb that can predict success with iOCT-assisted TCNR. More specifically, investigators hypothesize that filtering blebs with more extensive scarring as seen on pre-operative AS-OCT will benefit from iOCT.
Interventions
DEVICEDigital microscope integrated with intraoperative OCT (Zeiss Artevo 800, Carl Zeiss Meditec AG)
The Zeiss Artevo digital microscope integrated with iOCT (Zeiss Artevo 800, Carl Zeiss Meditec AG) is a commercially available, FDA approved device that can be utilized to visualize and evaluate the morphology of the trabeculectomy bleb during transconjunctival needle revision of trabeculectomy bleb.
DEVICESpectralis Anterior-segment OCT (AS-OCT) (Heidelberg Engineering)
The Spectralis Anterior-segment OCT (AS-OCT) is a commercially available, FDA approved device that can be utilized to visualize and evaluate the morphology of the trabeculectomy bleb in the office.
Sponsors
Northwestern University
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Briefly, the diagnosis of glaucoma is based on the presence of 2 or more of the following findings: 1) glaucomatous optic disc damage, defined as the presence of optic disc excavation, diffuse or focal neuroretinal rim thinning or notching, localized or generalized retinal nerve fiber layer (RNFL) thinning; 2) visual field defects consistent with glaucoma; and 3) IOP ≥ 22 mmHg. * Patients with glaucoma who have been advised to undergo TCNR of a failed trabeculectomy bleb by a glaucoma specialist at Northwestern Medicine * History of failed trabeculectomy (based on clinical features of the trabeculectomy bleb and elevated intraocular pressure) * Patients can have history of other glaucoma surgery or cataract surgery * The diagnosis of glaucoma is based on the presence of 2 or more of the following findings: 1) glaucomatous optic disc damage, defined as the presence of optic disc excavation, diffuse or focal neuroretinal rim thinning or notching, localized or generalized RNFL thinning; 2) visual field defects consistent with glaucoma; and 3) IOP ≥ 22 mmHg.
Exclusion criteria
* Age younger than 18 years; * Secondary causes of glaucoma (e.g., iridocyclitis, trauma); * Any evidence of corneal or conjunctival pathology adjacent to filtration bleb that could influence AS-OCT image * Patients who did not undergo surgery or have adequate follow up * Adults unable to consent, individuals who are not yet adults (infants, children, teenagers), pregnant women, prisoners and vulnerable populations
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Surgical Success | Postoperative month 3 | Surgical success as defined as a 20% reduction in unmedicated IOP below the pre-operative baseline at specified post-operative visits. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Number of Participants With Successful Imaging of the Bleb With iOCT | Intraoperative assessment | The secondary outcomes will be feasibility of intraoperative OCT. Feasibility will be defined as the percentage of cases with successful imaging of the bleb with iOCT. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Pre-operative AS-OCT Findings | Pre-operative visit | Investigators will also assess whether findings seen with pre-operative AS-OCT can predict what type of blebs will benefit from iOCT-assisted TNCR. Features of AS-OCT and iOCT imaging that will be assessed include quality of image capture, visualization of surgical site, and characteristics of the bleb. Characteristics of the surgical site include bleb height, internal reflectivity, location and number of adhesions, and presence of cysts, cavities, and fistulas. |
Countries
United States
Participant flow
Pre-assignment details
N/A. Single group, unmasked.
Participants by arm
| Arm | Count |
|---|---|
| Study Group Eyes scheduled to undergo trans-conjunctival needle revision of trabeculectomy bleb | 7 |
| Study Group Eyes scheduled to undergo trans-conjunctival needle revision of trabeculectomy bleb | 7 |
| Total | 14 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Overall Study | Did not undergo surgery or did not undergo imaging at the time of surgery | 3 |
Baseline characteristics
| Characteristic | Study Group |
|---|---|
| Age, Continuous | 65.4 years |
| Intraocular pressure (mmHg) | 17.65 mm Hg |
| Region of Enrollment United States | 7 participants |
| Sex: Female, Male Female | 6 Participants |
| Sex: Female, Male Male | 1 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 10 |
| other Total, other adverse events | 0 / 10 |
| serious Total, serious adverse events | 0 / 10 |
Outcome results
Primary
Surgical Success
Surgical success as defined as a 20% reduction in unmedicated IOP below the pre-operative baseline at specified post-operative visits.
Time frame: Postoperative month 3
Population: Subjects who underwent trans-conjunctival needle revision and who underwent intra-operative imaging
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Study Group | Surgical Success | Success | 5 participants |
| Study Group | Surgical Success | Failure | 2 participants |
Secondary
Number of Participants With Successful Imaging of the Bleb With iOCT
The secondary outcomes will be feasibility of intraoperative OCT. Feasibility will be defined as the percentage of cases with successful imaging of the bleb with iOCT.
Time frame: Intraoperative assessment
Population: All eyes that underwent trans-conjunctival needle revision and intra-operative imaging
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Study Group | Number of Participants With Successful Imaging of the Bleb With iOCT | 7 participants |
Other Pre-specified
Pre-operative AS-OCT Findings
Investigators will also assess whether findings seen with pre-operative AS-OCT can predict what type of blebs will benefit from iOCT-assisted TNCR. Features of AS-OCT and iOCT imaging that will be assessed include quality of image capture, visualization of surgical site, and characteristics of the bleb. Characteristics of the surgical site include bleb height, internal reflectivity, location and number of adhesions, and presence of cysts, cavities, and fistulas.
Time frame: Pre-operative visit