Baseer Ahmad

Comparison of intravitreal ranibizumab and bevacizumab for the treatment of macular edema secondary to retinal vein occlusion

AIM To compare the efficacy of ranibizumab and bevacizumab for macular edema due to retinal vein occlusion (RVO). METHODS A retrospective study was conducted at a single academic institution. Eighty-one patients naïve to anti-VEGF therapy with RVO and macular edema were identified. Twenty-six eyes were treated with ranibizumab, 33 eyes with bevacizumab, and 22 eyes with bevacizumab then switched to ranibizumab (crossover). The main outcome was change in visual acuity at 3 months, 6 months, and final visit. RESULTS The mean visual acuity improved from 20/80 to 20/40 in the ranibizumab (R) group and from 20/125 to 20/60 in the bevacizumab (B) group (P=0.66). The mean change in central subfield thickness (CST) was -186 and -212µm, respectively (P=0.69). Mean time between injections was 94±21.1d in the R group and 103.8±10.5d in the B group (P=0.78). In the crossover group, mean initial visual acuity was 20/125, reached 20/60 at crossover, and remained 20/60 at conclusion (P=0.91). CONCLUSION Both ranibizumab and bevacizumab are effective for the treatment of RVO and appear to have similar visual and anatomic outcomes. Changing treatments from bevacizumab to ranibizumab did not result in further gains in visual acuity.

Congenital optic nerve malformations

Aplasia of the optic nerve is characterized by complete absence of the optic nerve, absence of retinal vessels, and no light perception vision. It was first described in 1854 by von Graefe. Only a few dozen cases have been reported in the literature. Most have been unilateral. Aplasia of the optic nerve is congenital, and its etiology remains poorly understood. There is no known sex or racial predilection. No abnormal karyotypes have been reported. Two patients with aplasia were found to have PAX6 polymorphisms, but no familial cases have been reported. Others have had in utero exposures including acetone, maternal viral infection, and maternal tobacco use. Aplasia of the optic nerve has been induced in experimental animals by treating with hypoglycemic sulfonamides, creating folic acid deficiency, exposing fetuses to x-ray radiation, and treatment with actinomycin D. Some have argued that a local failure of mesoderm leads to a lack of normal vascular development within the optic nerve. Most pathologic specimens lack retinal ganglion cells, but a 3-day-old autopsy in 1 case of bilateral aplasia showed undifferentiated ganglion cells lacking axons and dendrites. Failure of these cells to elaborate axons may be the mechanism of this malformation. Alternatively, nerve fiber misdirection and subsequent atrophy could also lead to this phenotype. Pathologic studies have shown that the neural crest-derived optic nerve sheath tends to be present and connected to the back of these eyes despite the lack of nerve tissue. The retina tends to be dysplastic with rosette formation.

Presbyopia-correcting intraocular lenses and corneal refractive procedures: a review for retinal surgeons.

Purpose: To review the specific challenges and pitfalls that vitreoretinal surgeons may face when operating on eyes with presbyopia-correcting intraocular lenses or previous corneal refractive surgery. In addition, this review aims to familiarize vitreoretinal surgeons with specifications of currently available Food and Drug Administration–approved presbyopia-correcting intraocular lenses. Methods: Review of current literature performed with PubMed for search terms “presbyopia,” “correction,” “IOL,” “vitreoretinal,” “challenges,” and “surgical” both singly and in combination as well as closely related terms. Results and Conclusion: Specific intraoperative issues with presbyopia-correcting intraocular lenses that may be encountered include peripheral visualization, condensation, lens material issues particularly with silicone oil, decentration, Z-syndrome, and foveal image displacement. Every patient undergoing retinal surgery should also be asked about previous laser-assisted in situ keratomileusis/photorefractive keratectomy because those eyes require special attention to surface hydration and care to avoid epithelial removal if possible. Intracorneal ring segments and corneal inlays can cause effects similar to those of a small pupil. However, these can be managed with thorough preoperative evaluation and various intraoperative maneuvers. In addition, retinal physicians should be aware that macular disorders, such as age-related macular degeneration, may be exacerbated by potential loss of contrast sensitivity.

Bilateral subcutaneous emphysema from pressurized infusion during pars plana vitrectomy: a case report.

OBJECTIVES To report a case of extensive subcutaneous emphysema introduced during vitrectomy while using an advanced feedback-controlled pressurized infusion system. METHODS Clinical case report of a 56-year-old woman undergoing pars plana vitrectomy for rhegmatogenous retinal detachment of the left eye. The clinical and radiologic findings of the patients eyes were documented. The mechanisms of feedback-controlled pressurized infusion devices were reviewed to explain the adverse events. A search of PubMed was conducted to look for any similar cases and/or discussion. RESULTS In this surgical case, vitrectomy was completed with air-fluid exchange and a formed anterior chamber was observed with an estimated pressure of high teens to low 20s by the surgeon. After the undraping, the patient was noted to have severe facial crepitus extending to the clavicles. Immediate chest X-ray was done, followed by computed tomography, confirming orbital and subcutaneous emphysema, as well as the presence of perfluoro-N-octane in the left orbit. CONCLUSION Integrated pressurized infusion devices using feedback sensors allow for a sophisticated method of maintaining intraocular pressure and globe formation. However, inadvertent or occult globe rupture may lead to disruption of feedback control and subsequent high rates of infusion. As the infused substances exit the site of rupture, they can lead to extensive extraocular gas or fluid accumulation, and we report a case of severe bilateral subcutaneous emphysema as a result.

Peripapillary serous detachment in multiple evanescent white dot syndrome.

Background: To report the presence of transient peripapillary serous detachments in multiple evanescent white dot syndrome. Methods: Retrospective case series. Results: Four eyes of four patients diagnosed with multiple evanescent white dot syndrome presented with peripapillary serous detachments. Diagnosis was based on clinical presentation, fundus findings, and angiographic findings. All 4 were female with age ranges between 24 and 40 years and presented with photopsias, an enlarged scotoma contiguous with the blind spot, and chorioretinal white dots in the posterior pole with characteristic angiographic features. All of the serous detachments resolved or were greatly reduced concomitantly with the resolution of the patients other clinical symptoms and fundus findings. Conclusion: The authors report peripapillary serous detachments as a previously unreported manifestation of multiple evanescent white dot syndrome. These seem to be self limited with concurrent resolution with the rest of the patients symptoms.

Spectral-domain optical coherence tomography findings in acute retinal pigment epitheliitis.

PURPOSE To report new findings revealed by spectral-domain optical coherence tomography in a patient with bilateral acute retinal pigment epitheliitis. METHODS A patient presented with bilateral central scotoma and clinical and angiographic findings consistent with acute retinal pigment epitheliitis. Spectral-domain optical coherence tomography was performed at presentation and throughout follow-up. RESULTS Early spectral-domain optical coherence tomography showed hyperreflectivity throughout the full thickness of the foveola, suggesting a full-thickness foveal inflammatory disorder. Later images provide insight into the natural course of acute retinal pigment epitheliitis and eventually showed a small outer retinal defect similar to that reported in some patients with macular microhole or foveal red spot. CONCLUSION Acute retinal pigment epitheliitis is a macular inflammatory disorder that can involve the full thickness of the fovea and underlying retinal pigment epithelium and may result in a small defect in the outer retina similar to that reported in some patients with macular microhole or foveal red spot.

Retinal Complications After Refractive Surgery.

With the increasing acceptance of refractive surgery as treatment for refractive error, an awareness of potential complications is imperative. Refractive surgeries are categorized as keratorefractive procedures or lensbased procedures. Laser in situ keratomileusis (LASIK) and excimer laser photorefractive keratectomy (PRK) are the most commonly performed keratorefractive procedures. Lens-based refractive procedures include phakic intraocular lens (PIOL) implantation and refractive lens exchange (RLE). Retinal complications, although rare, have been reported following all forms of refractive surgery. Although lens-based refractive surgery shares a risk profile similar to that of other intraocular procedures, the association between keratorefractive surgery and retinal pathology is more vague. As most of these complications are reported in myopic eyes with higher risk of retinal pathology, it remains unknown whether the incidence differs from that in a comparable myopic population without refractive surgery. However, the short time interval between keratorefractive surgery and diagnosis of retinal pathology described in some cases, sometimes bilaterally, continues to prompt further attention. The most commonly reported adverse event involving the posterior segment is rhegmatogenous retinal detachment (RRD) after myopic LASIK. Other retinal pathologies noted after LASIK include choroidal neovascularization (CNV), macular hemorrhage, lacquer crack, and macular hole (MH). Nearly all of these other complications are, in fact, manifestations of myopic maculopathy. Retinal detachment, CNV, macular hemorrhage, MH, and cystoid macular edema