Michael Javaheri

Linezolid-induced optic neuropathy: a mitochondrial disorder?

We report a case of bilateral mitochondrial optic neuropathies secondary to long-term linezolid treatment, show the nature of recovery, review the findings in the literature and propose a potential mitochondrial mechanism for linezolid-induced mitochondrial optic neuropathy. This is an observational case report and literature review with presentation of the clinical course of linezolid mitochondrial optic neuropathies through clinical and psychophysical documentation. Main outcome measures included: visual acuity, funduscopical examinations and peripapillary retinal nerve fibre layer (PRNFL) optical coherence tomography (OCT). A 6-year-old boy presented with bilateral optic neuropathies secondary to 1 year of linezolid treatment for osteomyelitis of the mandible. On presentation, visual acuities were 20/400 in both eyes, with considerable optic disc oedema, hyperaemia and PRNFL swelling confirmed by OCT. 2 weeks after the discontinuation of linezolid, visual acuities returned to 20/25 in both eyes, with reduction in the optic disc oedema, hyperaemia and PRNFL swelling. 3 months after the discontinuation of linezolid treatment, visual acuities were stable at 20/20 in both eyes, with a marked decrease in PRNFL swelling confirmed by OCT, and the development of mild temporal optic disc pallor in both eyes. Doctors should be aware of impairments of vision among patients on long-term linezolid treatment and promptly discontinue treatment to prevent irreversible vision loss. The development and resolution of bilateral optic neuropathies with considerable PRNFL swelling in this patient provide insight into the more general rubric of mitochondrial optic neuropathies.

Transvitreal limited arteriovenous-crossing manipulation without vitrectomy for complicated branch retinal vein occlusion using 25-gauge instrumentation.

Purpose: To evaluate a new technique, 25-gauge transvitreal limited arteriovenous-crossing manipulation without vitrectomy (LAM), for the treatment of branch retinal vein occlusion (BRVO) complicated by macular hemorrhage and/or macular edema recalcitrant to grid laser photocoagulation. Methods: Twelve eyes of 12 patients underwent LAM for BRVO performed by a single surgeon (M.S.H.) using the 25-gauge nitinol flexible-extendable blunt pick. The presence or absence of intraoperative reperfusion visualization, pre- and postoperative visual acuity, macular thickness as measured by optical coherence tomography, intraocular pressure, and lens status were evaluated. Results: Restoration of blood flow was noted in all patients and was based on intraoperative reestablishment of a red column of erythrocytes through the previously closed vessel. Mean visual acuity improved from 20/200 (logarithm of the minimal angle of resolution [LogMAR] ± SD, 1.00 ± 0.32) preoperatively to 20/70 (LogMAR ± SD, 0.56 ± 0.28) (P = 0.0003) at the final visit. Eleven (92%) of 12 eyes had ≥2 lines of visual improvement. Five eyes (45%) had final visual acuity of 20/50 or better. Mean macular thickness ± SD improved from 401.0 ± 73.2 to 178.7 ± 19.6 &mgr;m (P < 0.0001) at the final visit. No statistically significant difference was noted in cataract progression or intraocular pressure. Mean follow-up ± SD was 49.9 ± 19.6 weeks. All patients were observed for at least 12 weeks. Conclusion: LAM may achieve outcomes comparable with those of arteriovenous adventitial sheathotomy for complicated BRVO.

Angiofibrotic Response to Vascular Endothelial Growth Factor Inhibition in Diabetic Retinal Detachment: Report No. 1

OBJECTIVES To assess the effect of bevacizumab injection on connective tissue growth factor (CTGF) and vascular endothelial growth factor (VEGF) in the ocular fluids of patients with diabetic traction retinal detachment, and to determine whether intraoperative and postoperative complications are decreased in eyes given adjunctive preoperative bevacizumab injection. METHODS Twenty eyes of 19 patients were randomized to receive intravitreal bevacizumab or sham injection 3 to 7 days before vitrectomy for severe proliferative diabetic retinopathy. We collected aqueous samples before injection and at the time of vitrectomy and extracted undiluted vitreous samples. RESULTS Five eyes had decreased vascularization of membranes from preinjection to the time of vitrectomy (all in the bevacizumab treatment arm). Median visual acuities were 20/400 in control eyes at baseline and postoperative month 3 (POM3) and 8/200 in the bevacizumab-treated group at baseline and 20/100 at POM3 (P= .30 between control and bevacizumab-treated groups at POM3). All retinas were attached at POM3. Vitreous levels of VEGF were significantly lower in the bevacizumab group than in the control group (P= .03). Vitreous levels of CTGF were slightly lower in the bevacizumab group compared with the control group, but this difference was not statistically significant (P= .38). Levels of CTGF in the aqueous were strongly correlated with CTGF levels in the vitreous of controls (Spearman correlation coefficient, 0.95 [P< .001]). CONCLUSIONS Intravitreal bevacizumab injection reduces vitreous levels of VEGF and produces a clinically observable alteration in diabetic fibrovascular membranes. Ocular fluid levels of CTGF are not significantly affected within the week after VEGF inhibition. Retinal reattachment rates and visual acuity are not significantly altered by preoperative intravitreal bevacizumab injection at POM3. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01270542.

Effect of oxygenated intraocular irrigation solutions on the electroretinogram after vitrectomy.

Purpose: To investigate the effect of oxygenated intraocular irrigating solutions on electroretinograms (ERGs) for postvitrectomy rabbits. Methods: Eight groups of five rabbits each underwent pars plana vitrectomy on the right eye; the left eye of each rabbit served as control. The intraocular irrigating solutions were balanced salt solution (BSS), BSS-plus, BSS + oxygen (BSS + O2), BSS-plus + O2, and combinations of each with the addition of endoillumination (L). All animals were evaluated by single-flash scotopic electroretinography on the operated and nonoperated eyes before surgery and at 1 hour, 1 day, 1 week, and 1 month after surgery by an unmasked observer. The main outcome measures were dark-adapted b-wave amplitudes of operated eye/nonoperated eye ratios. The results for the different groups were compared by analysis of variance. Results: Mean dark-adapted b-wave amplitudes of operated eye/nonoperated eye ratios ± SD for BSS-plus and BSS-plus + O2 before surgery and 1 hour, 1 day, 1 week, and 1 month after surgery were 1.01 ± 0.09, 0.50 ± 0.11, 0.95 ± 0.11, 0.97 ± 0.11, and 0.99 ± 0.08 and 0.98 ± 0.08, 0.59 ± 0.10, 0.92 ± 0.06, 0.97 ± 0.08, and 0.97 ± 0.10, respectively. At both 1 hour and 1 day after surgery, rabbits treated with BSS-plus + O2 had an earlier b-wave return to baseline findings, but the differences were not statistically significant (P > 0.05). Mean dark-adapted b-wave amplitudes of operated eye/nonoperated eye ratios ± SD for BSS and BSS + O2 before surgery and 1 hour, 1 day, 1 week, and 1 month after surgery were 1.02 ± 0.10, 0.47 ± 0.09, 0.77 ± 0.07, 0.89 ± 0.07, and 0.89 ± 0.07 and 1.02 ± 0.06, 0.62 ± 0.16, 0.94 ± 0.09, 0.97 ± 0.08, and 0.96 ± 0.06, respectively. One hour and 1 day after surgery, ERG readings for rabbits treated with BSS + O2 exhibited a statistically significantly earlier return of ERG voltage to baseline values compared with both BSS and BSS + L (P = 0.05 and P = 0.02, respectively). One day after surgery, rabbits treated with BSS alone had the lowest ERG ratios. One week and 1 month after surgery, for all solutions tested other than BSS, ERG values were within normal limits. Conclusion: The use of oxygenated solutions appears to affect ERG readings after pars plana vitrectomy. Further studies to evaluate the role of oxygenated solutions in different vitreoretinal surgical procedures are warranted.

Retinal thickness in normal and RCD1 dogs using optical coherence tomography.

BACKGROUND AND OBJECTIVE To compare retinal thickness and retinal nerve fiber layer (RNFL) thickness values obtained by optical coherence tomography (OCT) in normal dogs and dogs with rod-cone dysplasia type 1 (RCD1). MATERIALS AND METHODS Eight eyes of 6 normal hound-bred dogs and 12 eyes of 6 dogs with RCD1, 2 to 5 years of age, were examined using the Fast RNFL Thickness, Fast Macular Thickness, and line scan protocols of OCT. RESULTS Retinal thickness was significantly higher in the tapetal fundus than in the non-tapetal fundus, in both normal (P = .0036) and RCD1 (P < .0001) dogs. Superotemporal, superonasal, and inferior retinal thickness values were significantly higher in normal dogs (P < .0001). Area centralis thickness was 183.5 +/- 10.66 microm in normal dogs and 136.16 +/- 13.12 microm in RCD1 dogs (P < .0001). There was no difference in RNFL thickness between normal and RCD1 dogs (P > .05). CONCLUSION OCT scanning in dogs is considered to be a useful method of evaluation in future retinal studies in this animal model.

Presumed ocular tuberculosis presenting as a branch retinal vein occlusion in the absence of retinal vasculitis or uveitis

A 38-year-old Hispanic man presented with painless decreased vision in his right eye for 7 days. He had had no light perception with his left eye for 7 years, for which he was unable to provide a history. Visual acuity was 20/70 in the right eye (OD) and no light perception in the left eye (OS), with normal pressures in both eyes (OU). Slit-lamp examination showed an unremarkable OD, but disclosed a glaucoma-implant tube in a formed anterior chamber in the left eye, with posterior synechiae of the iris and a white cataract. Ophthalmoscopy of the right eye showed a superotemporal branch retinal vein occlusion with an associated serous retinal detachment involving the macula, without vitreous cell. The optic nerve and the remaining vessels and periphery were unremarkable. There was no view to the fundus in the left eye. Echography of the right eye did not show choroidal thickening, and in the left eye, …

Conjunctival epithelium in pars plana vitrectomy specimens

Purpose: To review histopathology of vitrectomy specimens obtained during routine pars plana vitrectomy (PPV) for evidence of inadvertent introduction of conjunctival epithelium into the vitreous cavity during PPV. Methods: Retrospective review of all vitreous specimens obtained from PPV over a 3-year period during which vitreous samples were routinely submitted from routine and diagnostic PPV. Patient charts and operative reports were reviewed, with particular attention to history of postoperative endophthalmitis, and the use of transconjunctival PPV. Results: A total of 650 specimens were obtained over a 3-year period. Three specimens with conjunctival epithelium were identified. None of these cases resulted in endophthalmitis. Two of these three cases used transconjunctival techniques. In one case all three sclerotomies were made using transconjunctival techniques. Conclusions: The presence of conjunctiva in the vitreous aspirate from completely transconjunctival PPV indicates that conjunctival epithelium can be inadvertently introduced into the vitreous cavity during PPV. Although none of these cases resulted in endophthalmitis, special care to sterilize the conjunctiva before the creation of transconjunctival sclerotomies is warranted.