Prospective evaluation of extraocular motility following double-plate molteno implantation

The surgical management of glaucoma: A review

After a long period of little change, glaucoma surgery has experienced a dramatic rise in the number of possible procedures in the last two decades. Glaucoma filtering surgeries with mitomycin C and glaucoma drainage devices remain the standard of surgical care. Other newer surgeries, some of which are minimally or microinvasive glaucoma surgeries, target existing trabecular outflow, enhance suprachoroidal outflow, create subconjunctival blebs, or reduce aqueous production. Some require the implantation of a device such as the iStent, Hydrus, Ex-PRESS, XEN and PRESERFLO, whilst others do not-Trabectome, Kahook dual blade, Ab interno canaloplasty, gonioscopy-assisted transluminal trabeculotomy, OMNI and excimer laser trabeculotomy. Others are a less destructive variation of an established procedure, such as micropulse transscleral cyclophotocoagulation, endoscopic cyclophotocoagulation and ultrasound cycloplasty. Cataract surgery alone can be a significant glaucoma operation. These older and newer glaucoma surgeries, their mechanism of action, efficacy and complications are the subject of this review.

Comparative Outcomes of the Molteno3 and Baerveldt Glaucoma Implants

PURPOSE

To compare outcomes between 2 nonvalved glaucoma drainage devices (GDDs) used to treat refractory glaucoma or in patients with neovascular/uveitic glaucoma likely to be poorly responsive to less aggressive therapies.

DESIGN

Retrospective, nonrandomized, multicenter comparative study.

PARTICIPANTS

A total of 117 eyes from 117 patients.

METHODS

Retrospective chart review of patients who underwent implantation of the Baerveldt (BGI) (Abbott Medical Optics, Abbott Park, IL) or the Molteno3 glaucoma implant (MGI) (Molteno Ophthalmic Limited, Dunedin, New Zealand). Noninferiority of the MGI versus the BGI was tested with Cox and mixed-effects regression models. Interventions in each group were analyzed with chi-square tests.

MAIN OUTCOME MEASURES

The primary outcome was time until device failure, defined as intraocular pressure (IOP) >21 mmHg or a reduction <20%, hypotony, reoperation for glaucoma, or loss of light perception. Secondary outcomes were intraoperative time, postoperative IOP, number of IOP-lowering medications, and visual acuity (VA).

RESULTS

The MGI could not be deemed noninferior to the BGI with regard to time until device failure (hazard ratio [HR], 0.83; confidence interval [CI], 0.41-1.65). The MGI was noninferior to the BGI when comparing postoperative IOP, a difference of -0.40 mmHg (95% CI, -1.74-0.93). The MGI needed 2% fewer medications (ratio of 0.98, 95% CI, 0.79-1.22), but noninferiority could not be claimed. With regard to VA, the MGI's mean was 0.10 logarithm of the minimum angle of resolution (logMAR) higher (95% CI, -0.01-0.21), but noninferiority testing was again inconclusive. Intraoperative time for the MGI was 15.7 minutes shorter versus the 350 mm² plate size BGI (P < 0.001) and 4.3 minutes shorter versus the 250 mm² plate size BGI (P = 0.32). More patients in the MGI group needed secondary operative management (11%, P = 0.03).

CONCLUSIONS

The MGI was noninferior to the BGI in lowering IOP. Differences in time until device failure, VA outcomes, and medication use were inconclusive. The MGI required more secondary operative interventions. The MGI required less time to implant than the BGI's 350 mm² plate size implant. Overall, the use of both GDDs is justifiable to lower IOP when more conservative management has failed.

Otago Glaucoma Surgery Outcome Study: Examining the Development of Strabismus Causing Diplopia in Patients Who Have Received Molteno Implant Surgery

OBJECTIVE

To evaluate the development of postoperative strabismus causing diplopia in patients who received Molteno implant surgery for the treatment of glaucoma.

METHODS

The Otago Glaucoma Surgery Outcome study (OGSOS) was used to select cases who had undergone Molteno implant surgery to examine the effect on the development of strabismus causing diplopia. Information was collected on treatments provided to correct motility disturbance, and their success, in this retrospective non-comparative study.

RESULTS

32 cases (3.3%) were found to have developed diplopia following the Molteno implant surgery from a total of 977 cases. Of these, the strabismus in 23 cases was described in sufficient detail to permit clinical categorization. Most (19/23) demonstrated an exodeviation, hyperdeviation, or a combination thereof, although 2/6 cases with superonasal plate location demonstrated a hypodeviation. Diplopia generally resolved spontaneously (20/32 cases). Treatment was required in eight cases, usually conservative and successful (6/8 cases), but strabismus surgery was required in two cases, and was unsuccessful.

CONCLUSIONS

This study found a low incidence of diplopia developing post-Molteno implant surgery. Strabismus features suggested a restrictive etiology, and spontaneous recovery was common (62.5%). Surgical correction proved unsuccessful - confirming persistent postoperative diplopia after Molteno implant surgery to be a rare but surgically challenging complication.

New developments in tube shunt surgery

PURPOSE OF REVIEW

This article reviews recent studies related to tube shunt surgery.

RECENT FINDINGS

Medical claims data and surveys of glaucoma surgeons demonstrate that tube shunts are being selected with increasing frequency as an alternative to trabeculectomy. A 5-year pooled analysis of the Ahmed Baerveldt comparison study and Ahmed versus Baerveldt study found a higher rate of surgical success with the Baerveldt glaucoma implant compared with the Ahmed glaucoma valve, but Baerveldt implantation carried a higher risk of hypotony. The primary tube versus trabeculectomy study showed trabeculectomy with mitomycin C produced greater intraocular pressure reduction with fewer glaucoma medications compared with tube shunt surgery as a primary procedure at 1 year, but trabeculectomy had a higher rate of postoperative complications. Adjunctive use of antifibrotic agents may enhance the success of tube shunt surgery. Implantation of a second tube shunt is effective in lowering intraocular pressure following primary tube shunt failure, but good results have also been reported with cyclophotocoagulation. Endothelial cell loss, diplopia, and tube shunt erosion are complications associated with these devices.

SUMMARY

The popularity of tube shunts has grown in recent years. Clinical trials and retrospective studies have provided valuable information to guide surgeons in the use of tube shunts. Increased efficacy of glaucoma procedures generally occurs at the cost of a higher risk of surgical complications.

Strabismus After Ocular Surgery

Many types of ocular surgery can cause diplopia, including eyelid, conjunctival, cataract, refractive, glaucoma, retinal, and orbital surgery. Mechanisms include direct injury to the extraocular muscles from surgery or anesthesia, scarring of the muscle complex and/or conjunctiva, alteration of the muscle pulley system, mass effects from implants, and muscle displacement. Diplopia can also result from a loss of fusion secondary to long-standing poor vision in one eye or from a decompensation of preexisting strabismus that was not recognized preoperatively. Treatment, which typically begins with prisms and is followed by surgery when necessary, can be challenging. In this review, the incidence, mechanisms, and treatments involved in diplopia after various ocular surgeries are discussed. [J Pediatr Ophthalmol Strabismus. 2017;54(5):272-281.].

Strabismus and binocular diplopia due to advanced glaucomatous visual field loss

PURPOSE

To describe a small series of patients with glaucoma whose strabismus and binocular diplopia were due to advanced visual field loss and inability to maintain sensory and motor fusion.

METHODS

This study is an observational case series of 3 patients with binocular diplopia, associated with variable strabismus, which was due to advanced visual field loss.

RESULTS

Specific characteristics of the strabismus associated with advanced glaucomatous visual field loss were a subjective floating second image and marked variability of the prism and alternate cover measurements. Measured hypertropia changed in magnitude over a few seconds or a few minutes (even in 1 patient to a hypotropia), which distinguishes this specific type of strabismus from other types of comitant or incomitant strabismus associated with glaucoma. Although visual acuity was 20/400 or better in both eyes in all patients, there was advanced visual field loss in at least one eye. All patients responded poorly to prism, but their symptoms improved with a Bangerter filter applied to the spectacle lens or a MIN occlusion lens to further blur the worse-seeing eye.

CONCLUSIONS

Variable strabismus associated with advanced glaucomatous visual field loss appears to be a distinct clinical entity that should be distinguished from other types of strabismus associated with glaucoma. Management of this specific type of strabismus is limited by inadequate visual field to fuse, analogous to hemifield slide, and therefore prism and/or strabismus surgery is unlikely to be successful. Primary treatment options include optical blur with Bangerter filters or a MIN occlusion lens although some patients prefer to ignore the second image.

Strabismus surgery outcomes in eyes with glaucoma drainage devices

PURPOSE

To report strabismus surgery outcomes in eyes with prior implantation of glaucoma drainage devices (GDD).

METHODS

The medical records of patients who underwent strabismus surgery for ocular misalignment that developed after implantation of a GDD over a 13-year period at a single institution were examined retrospectively. Patient characteristics, deviation types, preoperative measurements, surgical procedures, and postoperative measurements were analyzed.

RESULTS

Of the 16 patients included, 14 had exotropia (34^Δ ± 16^Δ) and 11 had vertical deviations (15^Δ ± 7^Δ), of which 9 had concurrent exotropia and vertical deviations. Preoperatively, 9 patients had diplopia. The surgical approach was tailored to address the deviation most noticeable to the patient-horizontal, vertical, or both if the vertical component could be addressed by horizontal muscle supra- or infraplacement. Three patients underwent simultaneous horizontal and vertical surgery. All patients underwent strabismus surgery on an eye with a GDD. Surgical motor success (defined as horizontal deviation ≤10^Δ, vertical ≤4^Δ) was achieved in 42% of horizontal and 57% of vertical deviations. Postoperatively 74% of deviations decreased by ≥50% in magnitude. Diplopia resolved in 50% of patients who presented with preoperative diplopia. One patient had intraoperative bleb perforation, but none had postoperative hypotony at any follow-up visit. Only 2 required a second strabismus surgery.

CONCLUSIONS

Strabismus surgery with preservation of the filtering bleb following implantation of a glaucoma drainage device is a low risk procedure that can improve ocular alignment and related symptoms, despite a low motor success rate by standard criteria.

Diplopia in Medically and Surgically Treated Patients with Glaucoma

PURPOSE

To report the prevalence, type, and cause of diplopia in medically and surgically treated patients with glaucoma.

DESIGN

Cohort study.

PARTICIPANTS

A total of 195 adult patients with glaucoma treated in a glaucoma referral practice.

METHODS

A total of 195 adult patients with glaucoma who had undergone surgical or medical management were prospectively enrolled. Forty-seven patients had undergone glaucoma drainage device (GDD) surgery (Baerveldt 350, Baerveldt 250 [Abbott Medical Optics, Abbott Park, IL], or Ahmed FP7 [New World Medical Inc, Rancho Cucamonga, CA]), 61 patients had undergone trabeculectomy, and 87 patients were medically treated. All patients completed the Diplopia Questionnaire to assess diplopia. We defined the presence of diplopia as "sometimes," "often," or "always" in distance straight ahead or reading positions on the Diplopia Questionnaire. A chart review was performed jointly by a strabismus specialist and a glaucoma subspecialist to characterize the type and cause of the diplopia.

MAIN OUTCOME MEASURES

Frequency, type, and cause of diplopia.

RESULTS

Diplopia was reported in 41 of 195 medically and surgically treated patients (21%) with glaucoma. Binocular diplopia due to the glaucoma procedure was present in 11 of 47 patients (23%) after GDD (95% confidence interval, 12-38), which was significantly greater than in patients after trabeculectomy (2/61 [3%]; 95% confidence interval, 0.4-11; P = 0.002). The most common type of strabismus associated with binocular diplopia due to glaucoma surgery was hypertropia (10/11 GDD cases, 2/2 trabeculectomy cases). Monocular diplopia was found in a similar proportion of medically treated, post-trabeculectomy, and post-GDD cases (4/87 [5%], 4/61 [7%], and 2/47 [4%], respectively). Binocular diplopia not due to surgery was found in similar proportions of GDD, trabeculectomy, and medically treated cases (3/47 [6%], 5/61 [8%], and 10/87 [11%], respectively).

CONCLUSIONS

Diplopia may be under-recognized in medically and surgically treated patients with glaucoma, and standardization of ascertaining patient symptoms using the Diplopia Questionnaire may be useful in these patients. Diplopia was more commonly seen after GDD than trabeculectomy, typically a noncomitant restrictive hypertropia. The prevalence of monocular diplopia and binocular diplopia unrelated to glaucoma surgery was similar among medical and surgical groups. It is important to counsel patients on the higher occurrence of diplopia associated with GDD surgery.

Diplopia after glaucoma surgery

The occurrence of strabismus and symptomatic diplopia following glaucoma surgery is becoming more common as the use of implanted setons increases. Understanding the factors contributing to the diplopia is critical to the development of treatment strategies to alleviate the patient's symptoms.

Diplopia after glaucoma drainage device implantation

PURPOSE

To determine incidence of diplopia after glaucoma drainage device (GDD) surgery and to report treatment outcomes.

METHODS

Financial claims data were used to identify patients who underwent GDD surgery (CPT [Current Procedural Terminology] 66180) at the Bascom Palmer Eye Institute from January 2, 1991, through December 31, 2005. After a second claims data search, the medical records of patients diagnosed with diplopia (International Classification of Diseases, 9th Revision code 368.2) and those who underwent extraocular muscle surgery (CPT-4 code 67311-67335) after GDD implantation were reviewed retrospectively.

RESULTS

A total of 2,661 patients underwent GDD surgery during the study period. Charges were submitted for 59 patients for strabismus surgery or office visits relating to diplopia. Of these, 27 patients were excluded because medical records did not document diplopia or included pre-existing diplopia, cranial nerve palsy, or diplopia attributed to another ocular procedure. The remaining 32 patients developed diplopia secondary to GDD. Superotemporal quadrant GDDs were identified in 23 eyes and inferonasal quadrant placement in 9 eyes. The 1-year cumulative incidence of diplopia was 1.4%. No patient developed diplopia after 1 year. The mean follow-up after diagnosis for patients with diplopia was 48 ± 27 months (range, 1-124 months). The mean time of onset of diplopia after GDD implantation was 66 ± 62 days, with median onset of 42 days (range, 8-278 days). Treatment of diplopia included prisms in 17 cases (53.1%), no treatment in 13 (40.6%), other therapies in 2 (6.3%), and surgery after prismatic treatment failed in 3 (9.4%).

CONCLUSIONS

The incidence of diplopia after GDD surgery is low, and most patients are treated with prisms.

Nonsurgical management of diplopia

Diplopia is a potential undesirable outcome of nearly any ocular surgery. In some cases, the unexpected strabismus and diplopia resolve quickly without intervention, especially if due to swelling or minor insult from the surgical procedure. When double vision persists, effective treatment may be more elusive in patients in which the strabismus is the result of a restrictive process. The sudden onset of strabismus makes treatment more challenging. Frequently these patients will require surgical intervention. Where possible, patients may be managed with nonsurgical treatments until the time of surgery or indefinitely if successful and acceptable to the patient. Diplopia has been documented as a result of restrictive strabismus following vitreoretinal surgery, glaucoma surgery, orbital decompression surgery, strabismus surgery, orbital surgery, conjunctival surgery, cataract surgery, blepharoplasty, and others. The treatment of diplopia after ocular surgery is complicated by the incomitance and torsion that may be associated with restrictive strabismus as well as the variability of the deviation during healing. Nonsurgical treatment options include prisms or occlusion. Fresnel prisms are used primarily, but occasionally the prism is ground into the spectacles. Occlusion of the involved eye may be partial or complete, using a "pirate" patch, adhesive patch, Bangerter foil, tape, or related method.

Update on aqueous shunts

Medicare claims data and surveys of the American Glaucoma Society membership show that aqueous shunts are being increasingly utilized in the surgical management of glaucoma. New clinical trials data have identified differences in the efficacy and safety of shunts in common use. Recent studies have reported comparable results with trabeculectomy and aqueous shunts in similar patient groups. Intraoperative and postoperative complications may develop with aqueous shunt surgery related to the implantation of a foreign material. Several modifications in surgical technique have been directed toward improving surgical success, reducing complications, and optimizing efficiency and cost.

Tube shunt complications and their prevention

PURPOSE OF REVIEW

Glaucoma drainage devices (GDDs) have been generally accepted as a treatment of refractory glaucoma. GDDs have their own unique set of complications that are important to evaluate to prevent them.

RECENT FINDINGS

Tube shunts are typically used in eyes with refractory glaucoma. There is increased interest in studying the efficacy of GDDs. Most of the attention has been focused on comparing trabeculectomy with the Baerveldt implant (Advanced Medical Optics, Inc., Santa Anna, California, USA). The other leading implant is the Ahmed Glaucoma Valve. There are several retrospective studies comparing these two devices and a prospective study is ongoing. There is great interest in the complication rate of tube shunts and these have been published both retrospectively and prospectively. Complications such as hypotony, diplopia, strabismus, proptosis, tube erosion, failure, corneal decompensation, endophthalmitis, and visual loss are all important and some have recently been reviewed in the literature. Moreover, the use of glaucoma drainage implants in the pediatric population has been evaluated.

SUMMARY

Glaucoma drainage implants have been a powerful tool in our surgical fight to prevent blindness; however, they are not without complications or controversy.

Motility disturbances in the tube versus trabeculectomy study during the first year of follow-up

PURPOSE

To describe the preoperative and postoperative motility disturbances encountered in the Tube Versus Trabeculectomy (TVT) Study during the first year of follow-up.

DESIGN

Multicenter randomized clinical trial.

METHODS

settings: Seventeen clinical centers. population: Patients 18 to 85 years old who had previous trabeculectomy and/or cataract surgery and uncontrolled glaucoma with intraocular pressure > or =18 mm Hg and < or =40 mm Hg on maximum tolerated medical therapy. interventions: 350-mm(2) Baerveldt glaucoma implant or trabeculectomy with mitomycin C (MMC). main outcome measures: Preoperative and postoperative evaluation of ocular motility and diplopia.

RESULTS

Motility disturbances were detected in 55 patients (28%) at baseline. New-onset persistent diplopia was reported in 5 patients (5%) in the tube group and no patients in the trabeculectomy group at 1 year (P = .06). A new postoperative motility disturbance developed or worsened in 7 patients (9.9%) in the tube group and no patients in the trabeculectomy group during the first year of follow-up (P = .005). Postoperative motility disturbances were also associated with increasing age (P < .001) and right eye surgery (P = .044).

CONCLUSIONS

Preoperative motility disturbances were common among patients in the TVT Study. New postoperative motility disturbances were more frequent following tube shunt surgery than trabeculectomy with MMC after 1 year of follow-up.

Aqueous drainage device surgery in refractory pediatric glaucoma: II. Ocular motility consequences

PURPOSE

To determine the prevalence of complications relating to ocular motility and alignment in children with refractory congenital and aphakic glaucoma treated with aqueous drainage device surgery.

METHODS

Chart review of consecutive children treated with aqueous drainage devices at Duke University Eye Center from 1995 to 2006 for ocular motility abnormalities and strabismus as well as sensorimotor testing results before and after aqueous drainage device placement.

RESULTS

Thirty-eight eyes of 30 children with congenital glaucoma and 41 eyes of 32 children with aphakic glaucoma were included. Optotype visual acuity testing could be performed in a minority of children preoperatively. After aqueous drainage device surgery, 14 and 20 eyes, respectively, were >20/100 in the congenital glaucoma and aphakic glaucoma groups. Only a few children had stereopsis or demonstrated binocular function on Worth 4-Dot testing in both groups before and after aqueous drainage device surgery. Horizontal and vertical strabismus was common, especially after aqueous drainage device surgery and occurred in 57% of congenital glaucoma patients and 47% of aphakic glaucoma patients. Motility limitation (both vertical and horizontal) was also common and occurred in 37% overall.

DISCUSSION

Ocular motility abnormalities and strabismus were common in children after aqueous drainage device surgery. These potential problems should be considered when aqueous drainage device surgery is planned, especially in children with binocularity.

Evaluation of ocular changes secondary to blowout fractures

There has been extensive debate over the standard of care of orbital fractures. Entrapment, diplopia, and hypoglobus, with or without enophthalmos, are the most common clinical indications for surgical intervention. Evaluation of these injuries is often limited in the early postinjury period because of edema. In assessing the severity of the injury, the clinician often uses parameters such as changes in visual acuity, patient-reported diplopia, gross changes in globe position, and an evaluation of the extraocular muscles. Many of these parameters are only grossly assessed and therefore are not specifically documented and tracked. The decision to proceed with surgical intervention may be based only on these gross clinical findings. The purpose of this article is to present a reliable and repeatable method for evaluating the degree of diplopia and the globe position of the orbital trauma patient by describing the use of the double Maddox rod test (Wilson Ophthalmic, Mustang, OK) and Hertel exophthalmometer (Wilson Ophthalmic). These methods can provide sequential documentation of the progression of the injury and help better define the need for surgical intervention and to follow the postoperative course.

Paralytic strabismus

In the last year, published works on paralytic strabismus have concerned many topics. New advances have been made in the knowledge of epidemiology of ocular nerve palsies in children, muscular causes of paralytic strabismus, and neuroimaging management of patients with third nerve palsy who are at risk of cerebral aneurysms. The author describes reports on rare associations of oculomotor imbalances and neurologic diseases as well as atypical orbital localizations of tumors. He also discuss new neuroimaging findings in congenital superior oblique muscle palsy and new acquisitions on cyclofusion deterioration in acquired trochlear palsy.