Michael R. Banitt

Lack of association between glaucoma and macular choroidal thickness measured with enhanced depth-imaging optical coherence tomography

PURPOSE To compare choroidal thickness measurements among normal eyes, eyes with normal tension glaucoma (NTG), and those with primary open-angle glaucoma (POAG), and to correlate choroidal thickness with demographic and clinical ocular parameters. METHODS Choroidal thickness was measured with enhanced depth-imaging (EDI) optical coherence tomography (OCT) in one eye of 38 normal, 20 NTG, and 56 POAG subjects and compared among groups. The mean age was 69.3 ± 13.6 years (60.1 ± 13.4 years for normal subjects and 73.8 ± 11.3 years for glaucoma subjects; P < 0.001). Measurements were made at the fovea and in the temporal and nasal choroid every 0.5 mm up to 3 mm away from the fovea. Univariate and multivariate linear regression analyses were performed to assess the association between choroidal thickness and demographic and ocular parameters. RESULTS There were no differences in foveal, temporal, or nasal choroidal thickness between normal, NTG, and POAG subjects (all P > 0.05) after adjusting for age, axial length, and intraocular pressure. Similarly, glaucoma severity groups did not differ from each other in all choroidal thickness measurements (all P > 0.05). Age (β = -1.78; P < 0.001) was the most significant factor associated with subfoveal choroidal thickness in the entire group, followed by axial length (β = -11.8; P = 0.002). CONCLUSIONS Choroidal thickness does not differ among normal, NTG, and POAG subjects, suggesting a lack of relationship between choroidal thickness and glaucoma based on EDI OCT measurements.

Evaluation and management of glaucoma after keratoprosthesis.

Purpose of review To review the causes and treatment of glaucoma in Boston keratoprosthesis (K-pro) recipients. Recent findings Glaucoma exists in up to three-quarters of patients who undergo K-pro surgery. After K-pro placement, intraocular pressure (IOP) is measured by digital palpation, which has been found to be reliable in trained observers. The onset or progression of glaucoma in K-pro patients should be monitored through visual field testing, direct visualization and structural imaging of the optic nerve. Although medical therapy is an option, one-half to three-quarters of K-pro recipients are surgically managed with a glaucoma drainage device (GDD) or, less commonly, cyclophotocoagulation. Summary Glaucoma is a common and permanent blinding sequelae of K-pro surgery. In K-pro patients, elevated IOP and changes in the optic nerve head should result in a high index of suspicion for glaucoma. Management is frequently surgical and typically entails placement of a GDD.

Progressive Loss of Retinal Ganglion Cell Function Precedes Structural Loss by Several Years in Glaucoma Suspects

PURPOSE We determined the time lag between loss of retinal ganglion cell function and retinal nerve fiber layer (RNFL) thickness. METHODS Glaucoma suspects were followed for at least four years. Patients underwent pattern electroretinography (PERG), optical coherence tomography (OCT) of the RNFL, and standard automated perimetry testing at 6-month intervals. Comparisons were made between changes in all testing modalities. To compare PERG and OCT measurements on a normalized scale, we calculated the dynamic range of PERG amplitude and RNFL thickness. The time lag between function and structure was defined as the difference in time-to-criterion loss between PERG amplitude and RNFL thickness. RESULTS For PERG (P < 0.001) and RNFL (P = 0.030), there was a statistically significant difference between the slopes corresponding to the lowest baseline PERG amplitude stratum (≤50%) and the reference stratum (>90%). Post hoc comparisons demonstrated highly significant differences between RNFL thicknesses of eyes in the stratum with most severely affected PERG (≤50%) and the two strata with least affected PERG (>70%). Estimates suggested that the PERG amplitude takes 1.9 to 2.5 years to lose 10% of its initial amplitude, whereas the RNFL thickness takes 9.9 to 10.4 years to lose 10% of its initial thickness. Thus, the time lag between PERG amplitude and RNFL thickness to lose 10% of their initial values is on the order of 8 years. CONCLUSIONS In patients who are glaucoma suspects, PERG signal anticipates an equivalent loss of OCT signal by several years.

Descemetʼs stripping with automated endothelial keratoplasty and glaucoma

Purpose of review Descemets stripping with automated endothelial keratoplasty (DSAEK) has recently become the preferred surgical procedure replacing penetrating keratoplasty (PKP) for corneal endothelial disorders. However, DSAEK may also be associated with postprocedure intraocular pressure elevation and secondary glaucoma, and presents unique surgical challenges in patients with preexisting glaucoma surgeries. Recent findings The relatively high rate of glaucoma induction or worsening after PKP has significant implications leading to corneal graft failure and irreversible vision loss from glaucomatous optic neuropathy. In contrast, DSAEK, in addition to providing excellent visual outcomes with faster recovery, may provide advantages over PKP with lower risk of serious, vision-threatening glaucoma-related complications. Pupillary block glaucoma, steroid-induced intraocular pressure elevation, and less commonly peripheral anterior synechiae development have been reported after DSAEK. In patients with preexisting glaucoma surgical procedures (trabeculectomy or tube shunts), special attention to techniques (which continue to evolve) are required to perform DSAEK safely and effectively. Summary As DSAEK continues to gain popularity and advance with more studies performed, our understanding of DSAEK-associated intraocular pressure elevation and secondary glaucoma-related complications will become more complete. Current limited data suggest that DSAEK may be a suitable surgical alternative to PKP in patients with corneal endothelial disease and coexistent glaucoma with or without prior glaucoma procedures with faster recovery and good visual outcomes.

The choroid in glaucoma.

Purpose of review Prior studies have not conclusively established a relationship between the choroid and glaucoma. The development of an enhanced imaging technique for spectral domain optical coherence tomography (SD-OCT) has allowed for measurements of choroidal thickness that are more accurate than previously possible. Therefore, the SD-OCT may be capable of documenting the changes in the choroid as they relate to glaucoma. Recent findings When applied to the SD-OCT, the technique of enhanced depth imaging allows for reproducible measurements of choroidal thickness. Nine reports have been published about choroidal thickness within the macula, as measured by OCT, in eyes with glaucoma. In six publications, there was no significant difference between the macular choroidal thicknesses of patients with glaucoma compared with those without glaucoma. Additional five studies have reported on peripapillary choroidal thickness in glaucoma patients. Although three of the studies determined that the peripapillary choroid is thinner in glaucoma patients, two others failed to establish this relationship. Summary The SD-OCT is capable of reproducibly measuring choroidal thickness in the peripapillary and macular areas. In those with glaucoma, choroidal thickness does not change within the macula. In a few subsets of glaucoma, the peripapillary choroid is thinner when compared with normals.

Evidenced-based comparison of aqueous shunts

Purpose of review This review provides an evidence-based comparison of aqueous shunts in common use. Recent findings Aqueous shunts are being used with increasing frequency in the surgical management of glaucoma. Recent retrospective studies and prospective clinical trials have compared the outcomes of different shunt designs. Larger end-plate size is associated with greater intraocular pressure (IOP) reduction, but there may be an upper limit beyond which a further increase in plate surface area does not contribute beneficially to pressure control. The biocompatibility of plate material may also influence shunt efficacy. The flow restrictor of the Ahmed glaucoma valve provides an added level of safety by reducing the risk of postoperative hypotony, but this implant also appears to have a higher incidence of bleb encapsulation. Summary Several aqueous shunts are commercially available, and all have been shown to be safe and effective in lowering IOP. Studies comparing aqueous shunts have provided valuable information to assist in surgical decision-making in similar patient groups.

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.

A case of polymicrobial keratitis violating an intact lens capsule.

Purpose: To report a case of polymicrobial keratitis resistant to topical and intraocular antibiotics with recurrence after penetrating keratoplasty. Methods: Case report. Results: We report a case of polymicrobial keratitis caused by Phialophora verrucosa, Candida tropicalis, and Propionibacterium acnes. Initial treatment included topical vancomycin, tobramycin, amphotericin B, voriconazole, and oral fluconazole, as well as subconjunctival amphotericin B. Penetrating keratoplasty was performed, and the infection seemed to have resolved until 4 weeks after keratoplasty. A second penetrating keratoplasty was performed, followed by 4 weekly intracameral injections of voriconazole. Two weeks after the fourth intracameral injection, the infection manifested as an active anterior-chamber reaction. The patients eye was subsequently enucleated. Histopathologic evaluation showed penetration of the crystalline lens by fungus at the site of synechiae between the intact lens capsule and iris. Conclusions: To our knowledge, this is the first documented case of a polymicrobial keratitis caused by a bacterium, yeast, and a fungus. It is the first histopathologic demonstration of fungal penetration of intact lens capsule from infected iris.

Technique for air bubble management during endothelial keratoplasty in eyes after penetrating glaucoma surgery.

Our purpose was to develop a technique for maintaining air within the anterior chamber during endothelial keratoplasty in eyes that have previously undergone trabeculectomy or a glaucoma drainage implant. Whole human globes and rabbits underwent penetrating glaucoma surgery to develop the technique. Without the aid of any additional device or manipulation, continuing to inject air into the anterior chamber as it escapes through the sclerostomy or tube eventually fills the subconjunctival space and allows for back pressure. This allows for a full anterior chamber air fill and brief elevation of intraocular pressure. We employed this overfilling technique on 3 patients with previous incisional glaucoma surgery to perform successful Descemet stripping endothelial keratoplasty without complication. We recommend using the overfilling technique when performing Descemet stripping endothelial keratoplasty surgery in eyes with previous penetrating glaucoma surgery because it is a simple technique without the need for pre- or postoperative manipulation.

Endophthalmitis Associated With Glaucoma Drainage Implants.

BACKGROUND AND OBJECTIVE To identify the clinical features, organisms, and treatment outcomes in patients with endophthalmitis associated with glaucoma drainage implants. PATIENTS AND METHODS A retrospective noncomparative case series. RESULTS Of the 13 patients, exposure occurred in eight eyes, including exposure of the tube in four eyes, exposure of the patch graft in three eyes, and exposure of the plate in one eye. In the remaining five eyes, either recent implant placement or conjunctival revision occurred. The most common organism was Staphylococcus epidermidis (five eyes). Intravitreal antibiotics were administered in all eyes, with the exception of one eye (primary evisceration). Removal of the implant was performed in six eyes and evisceration or enucleation was performed in three eyes. Median pre-infection visual acuity was 20/80 (range: 20/30 to hand motion). Visual acuity at last follow-up was no light perception (five eyes), light perception (two eyes), hand motion (one eye), and better than or equal to 20/200 (five eyes). CONCLUSION Clinical features associated with endophthalmitis include implant exposure and a history of recent surgery. Staphylococcus epidermidis was the most common isolate. Although removal of the implant was performed in many patients, successful treatment was accomplished in some patients without removal. Visual outcomes were generally poor. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:563-569.].