Avinoam Ophir

Optical Coherence Tomography as an Adjunctive Tool for Diagnosing Papilledema in Young Patients

PURPOSEnThe authors examined the peripapillary (3.4-mm diameter) retinal nerve fiber layer thickness (RNFL thickness) as depicted by optical coherence tomography (OCT) in young patients with pseudopapilledema or papilledema.nnnMETHODSnIn 17 consecutive patients (6 to 20 years old) with bilateral newly diagnosed papilledema or pseudopapilledema, the eye with the thicker mean global RNFL per patient was analyzed. Excluded were patients in whom cerebrospinal fluid opening pressure was between 190 and 250 mm H(2)O (gray zone). RNFL thickness was compared in eyes with papilledema and pseudopapilledema using the Mann-Whitney U test.nnnRESULTSnPapilledema was clinically diagnosed in 9 patients and pseudopapilledema in 6 patients; 2 patients were excluded. Median RNFL thickness in the eyes with papilledema was greater than that of both eyes with pseudopapilledema and controls at all 12 clock hours. In all 9 patients with papilledema, RNFL was thickened contiguously for 8 to 12 clock hours above the upper 95% confidence interval limit of normal.nnnCONCLUSIONnThe peripapillary RNFL thickness as depicted by OCT was found to be a reliable adjunctive tool in the differentiation of newly diagnosed papilledema and pseudopapilledema in young patients. Larger cohorts are required to confirm these observations and conclusion.

Delayed Filtering Bleb Encapsulation

Encapsulated filtering blebs concomitant with increased intraocular pressure (IOP) developed 47 and 6 months, respectively, after surgery in two women, 46 and 60 years old, respectively, who had undergone trabeculectomy operations in one eye. Both blebs were associated with mild anterior uveitis. Following treatment with topical steroids, cyclopentolate, hypotensive medications, and digital massage, the uveitis resolved and the IOP fell. The likely cause of these late-appearing encapsulated blebs was anterior uveitis.

Effects of 5-fluorouracil on proliferating fibroblasts in vivo

5-Fluorouracil (5-FU) is a potent inhibitor of the proliferation of fibroblasts, the main cell mediators of scar formation. The mechanism of the toxic effect of 5-FU on cancer cells is well known but unclear in nonmalignant cells. The histopathological effects of 5-FU on proliferating fibroblasts in vivo, 2 and 4 weeks after drug injection, are demonstrated here. An insertion of homologous fibroblasts into rabbits vitreous followed by one injection of 1 mg 5-FU causes intracytoplasmic accumulation of vacuoles, morphological changes and inhibition of collagen deposition in the matrix.

Changes in Müller cell plasma membrane specializations during subretinal scar formation in the rabbit

The aim of this study was to identify changes in Müller cell plasma membrane specializations during experimentally induced subretinal gliosis in rabbits. When rabbits are dosed with sodium iodate, large expanses of retinal pigment epithelium and photoreceptors are destroyed. They are replaced by a subretinal scar consisting mainly of the ascending processes of Müller cells. These processes transform from the slender, highly polarized structures seen in normal animals into irregular processes that form a glia limitans along the basement membrane of the pigment epithelium, left bare following its degeneration. As the scar processes extend through the subretinal space and contract this basement membrane, they undergo dramatic changes in shape that are especially apparent in three-dimensional computer reconstructions of serial thick sections examined by high-voltage electron microscopy. Other changes involve the intercellular junctions and apical microvilli normally associated with the external limiting membrane. These structures become scattered over the surfaces of the ascending processes and are eventually lost. Loss of microvilli is associated with disappearance of immunostaining for a specific glycoconjugate normally associated with the microvillar plasma membrane. The observations document profound changes in Müller cell structural and functional polarity during subretinal scar formation.

Encapsulated Filtering Bleb and Subconjunctival 5-Fluorouracil

Filtering bleb encapsulation (BE) involves fibroblast proliferation and collagen synthesis. We analyzed the effect of 5-fluorouracil (5-FU) on the inhibition of BE. Forty-one patients with primary open-angle glaucoma underwent trabeculectomy in one eye as an initial surgery. Twenty-one of these eyes, randomly chosen, were treated postoperatively with four to six 5-FU subconjunctival injections over 10 days to inhibit bleb scarring; the remaining 20 eyes did not receive 5-FU. After 12 to 24 months, the surgical success rate was significantly higher in the treated eyes (P less than .05). However, the incidence of BE was similar: two eyes (9.5% and 10%, respectively) in each group. The difference between the effect of 5-FU in the inhibition of BE and bleb scarring suggests that the characteristics of the two fibroblast populations are heterogeneous.

Pseudophakic Cystoid Macular Edema Associated with Extrafoveal Vitreoretinal Traction

Purpose: To describe an association between extrafoveal vitreoretinal traction and intractable chronic pseudophakic cystoid macular edema (CME) by the use of optical coherence tomography (OCT). Methods: In a retrospective case series study, charts and OCT findings of patients who had postoperative recalcitrant pseudophakic CME for at least 6 months and vitreoretinal traction membranes were analyzed. Excluded were eyes that either had another vitreoretinopathy that could affect the analysis or had undergone an intravitreal intervention. Results: Three eyes (three patients) with macular edema following uneventful cataract surgery were detected to be associated with multifocal extrafoveal vitreoretinal traction sites in each. Retinal edema that was underlying each of the traction sites in all eyes was in continuum in at least one site per eye with the central macular edema, thus manifesting as diffuse macular edema. Conclusion: Chronic pseudophakic macular edema may be related to extrafoveal vitreoretinal traction.

A Possible Role of Free Radicals in the Transplantation of Retinal Pigment Epithelial Cells

Oxygen-derived free radicals have been implicated in tissue injury following ischemia and reperfusion (reoxygenation). It has been hypothesized that the radicals are produced during the early reperfusion stage. Recently, submacular implantation of retinal pigment epithelium cells has been reported. It is probable that during the procedure, the transplant and the 180-degree folded outer retina underwent a period of ischemia, followed by reoxygenation. We, therefore, infer that free radicals were produced during the reoxygenation stage of the procedure, injuring both tissues. We suggest that these hypotheses be investigated with the aim of improving the surgical outcome in eyes with age-related macular degeneration.

Importance of 3-D image reconstruction of spectral-domain OCT on outcome of grid laser photocoagulation for diffuse diabetic macular edema.

AIMnTo present the outcome of modified grid laser photocoagulation (GLP) in diffuse diabetic macular edema (DDME) in eyes without extrafoveal and/or vitreofoveal traction.nnnMETHODSnInclusion criteria for the retrospective study were DDME eyes of patients with type II diabetes mellitus that had ≥4 months of follow-up following GLP. Only one eye per patient was analyzed. Using 3-D spectral-domain optical coherence tomography (3-D SD-OCT), eyes that had either extrafoveal or vitreofoveal traction, or had been previously treated by an intravitreal medication(s) were excluded. Treated DDME eyes were divided into 4 groups: A) Classic DDME that involved the central macula; B) edema did not involve the macular center; C) eyes associated with central epiretinal membrane (ERM); D) DDME that was associated with macular capillary dropout ≥2 disc-diameter (DD).nnnRESULTSnGLP outcome in 35 DDME eyes after 4-24 (mean, 13.1±6.9) months was as follows: Group A) 18 eyes with classic DDME. Following one or 2 (mean, 1.2) GLP treatments, best-corrected visual acuity (BCVA) improved by 1-2 Snellen lines in 44.4% (8/18) of eyes, and worsened by 1 line in 11.1% (2/18). Central macular thickness (CMT) improved by 7%-49% (mean, 26.6%) in 77.8% (14/18) of eyes. Causes of CMT worsening (n=4) were commonly explainable, predominantly (n=3) associated with emergence of extrafoveal traction, 5-9 months post-GLP. Group B) GLP(s) in DDME that did not involve the macular center (n=6) resulted in improved BCVA by 1-2 lines in 2 eyes. However, the central macula became involved in the edema process after the GLP in 3 (50%) eyes, associated with an emergence of extrafoveal traction in one of these eyes 4 months following the GLP. Group C) GLP failed in all 5 eyes associated with central ERM. Group D) GLP was of partial benefit in 2 of 6 treated eyes with macular capillary dropout ≥2DD.nnnCONCLUSIONnEyes with DDME that involved the macular center were found to achieve favourable outcomes after GLP(s) during mid-term follow-up, unless complicated pre-GLP or post-GLP by vitreoretinal interface abnormalities, often extrafoveal traction or ERM, or by capillary dropout ≥2DD. Prospective studies with larger cohorts are required.

Catheterization of the Renal Artery for in vivo Infusion of the Kidney in the Cat

A special cannula for direct intrarenal artery injections has been prepared from a 19-gauge Intracath®. This cannula (with its stylet) possesses a proper degree of flexibility in spite of its small caliber (o.d. 0.40 mm, i.d. 0.26 mm).The surgical procedure, which involves catheter insertion to one renal artery through the stump of the opposite renal artery, can be accomplished over a short period of time with essentially no blood loss This method affords an opportunity of studying the effect of various drugs directly injected into the isolated kidney in vivo. No changes in plasma renin concentration was observed in the animals after renal artery cannulation. This method enables chronic cannulation of the renal artery.

Chronic macular edema associated with extrafoveal vitreoretinal traction.

AIMnTo describe an association between extrafoveal vitreoretinal traction and chronic macular edema, either diffuse (DiME) or cystoid (CME), by the use of optical coherence tomography (OCT).nnnMETHODSnCharts and OCT findings of two patients with persistent DiME or persistent DiME accompanied by CME, both associated with extrafoveal vitreous traction membranes were analyzed. Excluded were eyes that either had another vitreoretinopathy that could affect the analysis, had undergone pars plana vitrectomy or that had been treated by intravitreal medications. An age-matched normal control group for OCT (n=12) allowed for the quantification of the normal macular thicknesses.nnnRESULTSnOne patient (one eye) following perforating ocular injury and one patient (one eye) of idiopathic origin, both with chronic macular edema refractive to conventional treatment, were found to be associated with extrafoveal vitreoretinal traction in each eye. Retinal edema that was underlying the traction site in each eye was in continuum with the central macular edema, thus manifesting as diffuse macular edema. The automatic central 6-radial lines program in the OCT enabled the detection of the traction site in one eye, while in the other eye the diagnosis was achieved only with the additional use of the Line group program.nnnCONCLUSIONnChronic diffuse macular edema might be related to extrafoveal vitreoretinal traction. Careful search with the diverse OCT programs should be made in order to detect extrafoveal traction sites. Further studies and a larger cohort are required to compare the efficacy of early vitrectomy or pharmacologic vitreolysis versus the current therapeutic approaches in these situations.