T. H. Mahmoud

Toll-like Receptor 2 Ligand-Induced Protection against Bacterial Endophthalmitis

BACKGROUND Activation of innate immunity plays a key role in determining the outcome of an infection. Here, we investigated whether Toll-like receptors (TLRs) are involved in retinal innate response and explored the prophylactic use of TLR2 ligand in preventing bacterial endophthalmitis. METHODS C57BL/6 mice were given intravitreal injections of Pam3Cys, a synthetic ligand of TLR2, or vehicle (phosphate-buffered saline) 24 h prior to Staphylococcus aureus inoculation. The severity of endophthalmitis was graded by slit lamp, electroretinography, histological examinations, and determination of bacterial load in the retina. The expression of cytokines/chemokines and cathelicidin-related antimicrobial peptide was assessed by enzyme-linked immunosorbent assay and Western blot, respectively. RESULTS Intravitreal injections of Pam3Cys up-regulated TLR2 expression in the retina of C57BL/6 mice, and Pam3Cys pretreatment significantly improved the outcome of S. aureus endophthalmitis, preserved retinal structural integrity, and maintained visual function as assessed by electroretinography in C57BL/6 mice. Furthermore, Pam3Cys pretreatment activated retinal microglia cells, induced the expression of cathelicidin-related antimicrobial peptide, and remarkably reduced the bacterial load. CONCLUSIONS This is the first report that highlights the existence and role of TLR2 in retinal innate immune response to S. aureus infection and suggests that modulation of TLR activation provides a novel prophylactic approach to prevent bacterial endophthalmitis.

Intraocular pressure instability after 23-gauge vitrectomy.

Purpose: The purpose of this study was to describe outcomes, trends, risk factors, and protective factors for intraocular pressure (IOP) spikes in patients undergoing 23-gauge pars plana vitrectomy. Methods: A retrospective review in an academic institution was performed on all eyes undergoing 23-gauge vitrectomy with at least 1-month follow-up. The main outcome measures included IOP and operative complications. Results: Ninety-seven eyes of 93 patients were included. Intraocular pressure spikes >22 in the first month occurred in 73% of eyes with or suspect for glaucoma versus 46% of eyes without (P = 0.017); 76% of eyes with a gas fill versus 44% of eyes with a fluid fill (P = 0.0036); and 21% of eyes started on IOP-lowering drops on postoperative day 1 versus 49% of eyes who were not (P = 0.0033). Complications included retinal tears (3%), intraoperative retinal detachment (2%), and postoperative retinal detachment (2%). Fifteen percent of eyes required suturing of at least one sclerotomy. There were no cases of postoperative hypotony or endophthalmitis. Conclusion: Patients with or suspect for glaucoma or those with a gas fill may be at risk for high postoperative IOP during the first month. Aggressive early treatment of IOP may prevent IOP spikes in the early postoperative period.

Combined posterior chamber intraocular lens, vitrectomy, retisert, and pars plana tube in noninfectious uveitis

OBJECTIVE To assess the safety and efficacy of combined cataract extraction, posterior chamber intraocular lens placement, pars plana vitrectomy, fluocinolone acetonide intravitreal implant (Retisert), and Ahmed valves with pars plana tube (CPR-PT) in eyes with chronic, posterior, noninfectious uveitis. METHODS Retrospective study of patients who underwent CPR-PT. Outcome measures included visual acuity, intraocular pressure, inflammation, and complications. RESULTS Eight eyes were included, with a mean follow-up of 18 months. Mean visual acuity improved from 1.89 to 0.14 logMAR (Snellen, counting fingers at 2 ft [0.6 m]) to 20/30; P=.01). Mean intraocular pressure remained stable at 16 to 17 mm Hg (P=.35). The number of glaucoma medications per eye decreased from 2.9 to 0.25 (P=.01). Systemic prednisone therapy was discontinued in all patients by 9 months postoperatively. Inflammation was well controlled in all eyes. CONCLUSION The CPR-PT procedure allows rapid visual rehabilitation without major short-term complications.

Surgical Treatment of Age-Related Macular Degeneration

Choroidal neovascularization (CNV) and geographic atrophy (GA) are serious and potentially devastating complications of age-related macular degeneration (AMD), a leading cause of blindness in the developed world. While anti-vascular endothelial growth factor (VEGF) therapies have emerged as the current standard treatment of choice for choroidal neovascularization, the requirement for indefinite injections places a tremendous burden on physicians and patients, and may have disappointing outcomes in hemorrhagic neovascular AMD. No superior agents exist to treat large subretinal hemorrhage and geographic atrophy. Over the years, several vitreoretinal surgical approaches have been developed to treat macular degeneration, and these surgical options may still play a role in the management of specific complications of AMD. This review summarizes the principles, techniques, and results of surgical treatments for neovascular and non-neovascular age-related macular degeneration, with emphasis on submacular surgery for removal of CNV, full and limited macular translocation, retinal pigment epithelium, and choroid transplants as well as treatment of thick subretinal hemorrhage.

Complications associated with clear corneal cataract wounds during vitrectomy

Purpose:The purpose of this study was to report the intraoperative surgical complications that occurred during vitrectomy surgery associated with clear corneal incisions from previous cataract surgery. Methods:Retrospective, multicenter, case series, and chart review of five patients. Results:Five patients, 3 men and 2 women, with a median age of 75 years (range, 59-78 years), were followed up for a median of 7.5 months (range, 6 months to 5 years). In each eye, the patient had previously undergone cataract surgery and intraocular lens implantation through a clear corneal wound. Each patient developed a surgical complication during the subsequent vitrectomy related to leakage through the clear corneal wound. Vitrectomy was performed for retained lens fragments (three), macular hole (one), and repair of combined rhegmatogenous/tractional diabetic retinal detachment (one). Twenty-gauge vitrectomy was performed in 3 cases; 23-gauge in 1 case; and a combined 25- and 20-gauge vitrectomy was used in 1 case. Median time between cataract surgery and vitrectomy was 8 days (range, 0-14 days). Median preoperative visual acuity was 20/200 (20/50 to hand motions), and median postoperative visual acuity was hand motions (20/40 to light perception). In all five eyes, the clear corneal wound was found to leak extensively with minimal manipulation of the sclera at the pars plana. Leakage through clear corneal wounds occurred during marking of the sclerotomy site (Case 1), during placement of a 23-gauge infusion cannula (Case 2), during lens fragmentation (Case 3), during retinotomy and retinectomy (Case 4), and during scleral depression (Case 4). Four eyes developed choroidal detachment associated with hypotony caused by leakage through the clear corneal wound. Three of these eyes developed hemorrhagic choroidal detachment with subretinal and/or vitreous hemorrhage. One eye developed iris incarceration and anterior subluxation of a sulcus-placed intraocular lens associated with leakage through the clear corneal wound. In all five cases, extra sutures were placed to secure the clear corneal incision, and the cases were able to be completed. Two eyes underwent repeat vitrectomy to address complications associated with hemorrhagic choroidal detachments. Median final visual acuity was 20/400 (range, 20/40 to hand motions). The retina remained attached in all cases at the latest follow-up visit. Conclusion:Intraoperative complications related to clear corneal incisions can occur during pars plana vitrectomy. We recommend that cataract surgeons encountering complications during surgery should secure clear corneal wounds in anticipation of eventual vitrectomy surgery. It is incumbent on the retinal surgeon to carefully inspect the corneal wound at the start of the vitrectomy procedure and to close it with sutures if it appears to leak with minimal manipulation. This should help to minimize additional intraoperative and/or long-term complications.

Impact of ocular hypotensive lipids on clinically significant diabetic macular edema.

Purpose To study the impact of ocular hypotensive lipids (OHL) on the incidence, progression, and response to treatment of clinically significant diabetic macular edema (CSDME). Methods A total of 379 patients (232 female, 147 male) with a history of diabetes mellitus (DM) and primary open-angle glaucoma (POAG) were identified and included in the study. Patients were stratified into groups based on CSDME development and OHL exposure. Main outcome measures included time to development of CSDME, total duration of OHL exposure, and duration of DM and POAG. Results Seven patients (1.8%) developed CSDME after OHL exposure (group 1A), 15 (4.0%) developed CSDME prior to OHL exposure (group 1B), and 197 (52.0%) were treated with OHL but never developed CSDME (group 2). Of patients not exposed to OHL, 22 (5.8%) developed CSDME (group 3) and 138 (36.4%) did not (group 4). Mean duration of DM was longer (p<0.0001) in patients who developed CSDME (20.2 years) compared to patients who did not (12.4 years). There was no difference (p=0.67) in the amount of OHL exposure between patients who developed CSDME (4.1 years) and patients who did not (4.6 years). Once developed, there was no difference in the interval until CSDME resolution between OHL treated (17.8 mo) and untreated (12.7 mo) patients (p=0.36). Conclusions The CSDME development correlated most strongly with the duration of diabetes, irrespective of OHL use. Ocular hypotensive lipids treatment of POAG seems not to affect the incidence, progression, or response to treatment of CSDME in diabetes.