Michael P. Blair

Thickness profiles of retinal layers by optical coherence tomography image segmentation.

PURPOSE To report an image segmentation algorithm that was developed to provide quantitative thickness measurement of six retinal layers in optical coherence tomography (OCT) images. DESIGN Prospective cross-sectional study. METHODS Imaging was performed with time- and spectral-domain OCT instruments in 15 and 10 normal healthy subjects, respectively. A dedicated software algorithm was developed for boundary detection based on a 2-dimensional edge detection scheme, enhancing edges along the retinal depth while suppressing speckle noise. Automated boundary detection and quantitative thickness measurements derived by the algorithm were compared with measurements obtained from boundaries manually marked by three observers. Thickness profiles for six retinal layers were generated in normal subjects. RESULTS The algorithm identified seven boundaries and measured thickness of six retinal layers: nerve fiber layer, inner plexiform layer and ganglion cell layer, inner nuclear layer, outer plexiform layer, outer nuclear layer and photoreceptor inner segments (ONL+PIS), and photoreceptor outer segments (POS). The root mean squared error between the manual and automatic boundary detection ranged between 4 and 9 mum. The mean absolute values of differences between automated and manual thickness measurements were between 3 and 4 mum, and comparable to interobserver differences. Inner retinal thickness profiles demonstrated minimum thickness at the fovea, corresponding to normal anatomy. The OPL and ONL+PIS thickness profiles respectively displayed a minimum and maximum thickness at the fovea. The POS thickness profile was relatively constant along the scan through the fovea. CONCLUSIONS The application of this image segmentation technique is promising for investigating thickness changes of retinal layers attributable to disease progression and therapeutic intervention.

A loss of function mutation in the COL9A2 gene causes autosomal recessive Stickler syndrome.

Stickler syndrome is characterized by ocular, auditory, skeletal, and orofacial abnormalities. We describe a family with autosomal recessive Stickler syndrome. The main clinical findings consisted of high myopia, vitreoretinal degeneration, retinal detachment, hearing loss, and short stature. Affected family members were found to have a homozygous loss‐of‐function mutation in COL9A2, c.843_c.846 + 4del8. A family with autosomal recessive Stickler syndrome was previously described and found to have a homozygous loss‐of‐function mutation in COL9A1. COL9A1, COL9A2, and COL9A3 code for collagen IX. All three collagen IX α chains, α1, α2, and α3, are needed for formation of functional collagen IX molecule. In dogs, two causative loci have been identified in autosomal recessive oculoskeletal dysplasia. This dysplasia resembles Stickler syndrome. Recently, homozygous loss‐of‐function mutations in COL9A2 and COL9A3 were found to co‐segregate with the loci. Together the data from the present study and the previous studies suggest that loss‐of‐function mutations in any of the collagen IX genes can cause autosomal recessive Stickler syndrome.

Fluorescein angiography to estimate normal peripheral retinal nonperfusion in children

PURPOSE To estimate the normal distance from vascular termini to ora serrata in childrens eyes. METHODS Clinical records and peripheral fluorescein angiography images of the ora serrata region, taken using scleral indentation and the RetCam system during examination under anesthesia, were retrospectively reviewed from consecutive patients with presumed normal peripheral retinal vasculature. All patients had ocular disease either only in the fellow eye or if in the study eye, to a degree judged not likely to affect peripheral retinal vascular development. RESULTS The record review identified 33 eyes of 31 patients with presumed normal peripheral vasculature. Mean age at angiography was 3.8 years (range, 2 months to 13 years). Mean area of nonperfusion was 0.9 disk diameters (DD) temporally (range, 1.5-0.5 DD; SD 0.3) and 0.6 DD nasally (range, 1-0.25 DD; SD 0.2). CONCLUSIONS In children up to 13 years of age, the avascular retina normally extends 1.5 DD or less temporally and 1.0 DD or less nasally from the ora serrata. Conservatively, ≥ 2 DD of nonperfusion, 3 standard deviations more than normal, should be considered abnormal and a sign of peripheral nonperfusion. These data may serve as preliminary indicators of the range of normal when evaluating diseases with retinal vascular abnormalities in children.

Intravitreal Bevacizumab for Neovascular Glaucoma

PURPOSE To report 6-month and 1 year outcomes of eyes treated for neovascular glaucoma (NVG) with intravitreal bevacizumab injection and panretinal laser (PRP) compared to those receiving PRP alone. DESIGN retrospective, consecutive case series. METHODS Charts of patients with NVG from retinal ischemia and at least 6 months of follow-up were reviewed. Patients were treated with one injection of 1.25 mg intravitreal bevacizumab followed by PRP or with PRP alone. The primary outcome was the long-term angle anatomy. Secondary measures included intraocular pressure (IOP), visual acuity, patient compliance, and control of systemic diseases. RESULTS Fourteen eyes of 12 patients treated with bevacizumab and PRP and 15 eyes of 11 patients treated with PRP alone were included in the study. Mean sectors of open angle at baseline was 1.31 in the bevacizumab group and 1.47 in the retinal ablation group (P = 0.73). Mean sectors of open angle was 2.14 and 1.18 in the bevacizumab and retinal ablation groups, respectively (P < 0.05) at 6-month follow-up, and 2.27 and 1.18, respectively (P < 0.05) at 1-year follow-up. Mean baseline IOP was 32.3 mmHg (+/-14.8) in the bevacizumab group and 31.8 mmHg (+/-13) in the PRP group (P = 0.75). At 6-month follow-up, the mean IOP was 18.28 mmHg (+/-10) in the bevacizumab group and 23.33 mmHg (+/-14.6) in the PRP group (P = 0.05), and 19.12 mmHg (+/-6.8) and 26.2 mmHg (+/-18) (P = 0.1), respectively at 1-year follow-up. Nineteen patients were judged to be noncompliant, 10 had uncontrolled diabetes and 7 had uncontrolled hypertension. CONCLUSIONS This study documents better long-term preservation of open angle and IOP control in eyes receiving bevacizumab along with PRP. We stress that NVG is still associated with poor visual acuity outcomes.

Fluorescein Angiography of Recurrent Retinopathy of Prematurity After Initial Intravitreous Bevacizumab Treatment

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Very late reactivation of retinopathy of prematurity after monotherapy with intravitreal bevacizumab

The authors report a case of very late reactivation of retinopathy of prematurity (ROP) after bevacizumab monotherapy. A female born at 630 g and 24 weeks received two bilateral treatment of bevacizumab (Avastin; Genentech, South San Francisco, CA) for aggressive posterior ROP (APROP). At 2.5 years of age, ROP reactivated in the form of tractional retinal detachment in one eye and milder reactivation in the other. Although intravitreal bevacizumab treatment is effective in inducing regression of ROP, late reactivation and retinal detachments can occur after initial extended quiescence. Due to alterations of disease progression after bevacizumab, close follow-up by peripheral fluorescein angiography and laser ablation of persistent avascular retina is recommended to prevent disease reactivation and progression to retinal detachment.

Subretinal fluid in acute posterior multifocal placoid pigment epitheliopathy

Purpose: The purpose of this study was to describe the clinical finding of macular subretinal fluid by optical coherence tomography in patients with acute posterior multifocal placoid pigment epitheliopathy. Methods: Patients with acute posterior multifocal placoid pigment epitheliopathy were identified, and those with macular serous retinal detachment noted clinically and confirmed by optical coherence tomography are described. Results: Of 8 patients with acute posterior multifocal placoid pigment epitheliopathy evaluated by the uveitis service at the Illinois Eye and Ear Infirmary between 2003 and 2008, 4 eyes of 3 patients presented with macular subretinal fluid. Confirmatory optical coherence tomography was performed in two patients. Conclusion: Acute posterior multifocal placoid pigment epitheliopathy may present clinically with macular subretinal fluid. This finding can be confirmed and monitored with optical coherence tomography.

Treating uveitis-associated hypotony with pars plana vitrectomy and silicone oil injection.

Purpose: The purpose of this study was to determine the effect on intraocular pressure (IOP) and visual acuity of treating uveitis-related hypotony in patients with vitrectomy and intravitreal silicone oil injection. Methods: Patients who underwent pars plana vitrectomy and silicone oil injection for uveitis-associated hypotony treatment were identified retrospectively. The primary outcome was maintaining an IOP of ≥5 mmHg. Visual acuity improvement was defined as an increase in ≥2 lines of acuity. Results: Twelve eyes of 10 patients were identified. Median preoperative IOP was 2 mmHg (range: 0–7 mmHg). Two of 12 eyes had an IOP of ≥5 mmHg at presentation. The number of eyes with an IOP of ≥5 mmHg was 7 of 12 eyes (58%) at 1 month, 4 of 12 eyes (33%) at 3 months, 6 of 12 eyes (50%) at 6 months, and 3 of 9 eyes (33%) at 1 year. Five of 12 eyes (42%) were reinjected between 1 and 3 times with silicone oil for recurring hypotony. Median presenting Snellen visual acuity was counting fingers (range: 20/125 to light perception). Seven of 9 eyes (78%) maintained their preoperative vision at 1 year. Conclusion: Intraocular pressure elevated modestly in most patients in this series. However, results were often transient, and some eyes required repeated silicone oil injections. Although silicone oil is reasonable to consider for the treatment and maintenance of IOP in patients with ocular hypotony secondary to uveitis, better treatments are needed.

Retrospective case series of juxtafoveal choroidal neovascularization treated with photodynamic therapy with verteporfin

Purpose: To describe visual acuity and angiographic outcomes of juxtafoveal choroidal neovascularization (CNV) treated with photodynamic therapy and verteporfin (PDT). Methods: Four hundred eighty-four consecutive eyes of 446 patients treated with PDT from January 1, 2001, to June 30, 2002, were identified from billing records. Fluorescein angiograms were reviewed retrospectively to identify juxtafoveal CNV. Eligible patients had CNV in which the central boundary of the lesion was between 1 and 199 μm from the geometric center of the foveal avascular zone (FAZ). Patient charts were reviewed for visual acuity of the treated eye before PDT and at 6- and 12-month follow-up examinations. Presence of subfoveal CNV at 6 and 12 months of follow-up was determined by review of fluorescein angiograms. A lesion was considered subfoveal if it extended underneath the geometric center of the FAZ. Results: Twenty-one eyes had juxtafoveal CNV. Median change in visual acuity both 6 and 12 months after the initial PDT was 0 lines (n = 18 at 6 months, range −14 to + 8 lines; n = 17 at 12 months, range −18 to + 7 lines). Eleven lesions progressed to a subfoveal location by 12 months. Visual acuity in eyes with progressive lesions decreased a median of 4 lines of vision. Conclusions: Despite a small sample size and limited length of follow-up, this study shows that visual acuity on average can remain stable for at least 12 months after PDT of juxtafoveal lesions. Growth through the foveal center still can occur, however, and this can be associated with substantial visual loss.

Effects of Green Diode Laser in the Treatment of Pediatric Coats Disease

PURPOSE To review the effect of green diode laser ablation therapy on retinal structure and functional outcome in patients with advanced Coats disease. DESIGN Retrospective, interventional case series. METHODS Fourteen eyes of 13 patients with Coats disease were included in this study. Medical records, Retcam photographs (Clarity Medical Systems, Pleasanton, CA), and fluorescein angiograms were reviewed. All patients initially were treated with green diode laser (532 nm) ablation therapy to areas of the retinal telangiectasis associated with exudation. Main outcome measures included visual acuity, treatment outcome defined as complete resolution of telangiectatic lesions or exudative detachment, and macular status at the end of follow-up. RESULTS Before treatment, 1 eye was at stage 2 (telangiectasis and exudation), 12 eyes were at stage 3 (exudative retinal detachment), and 1 eye was at stage 4 (total retinal detachment with glaucoma). Five eyes had highly detached retina of more than 4 mm. Median age at diagnosis was 51 months (range, 0.5 to 153 months). Median follow-up was 39.5 months (range, 15 to 70 months). Median number of green diode laser photocoagulation treatments was 2 (range, 1 to 5). After laser photocoagulation, 13 (93%) of 14 eyes had no active exudation. Functionally, 4 (29%) of 14 eyes had 20/50 or better visual acuity, 3 (21%) of 14 eyes had 20/60 to 20/200 visual acuity, 5 (36%) of 14 eyes had 20/400 to light perception visual acuity, and 2 (14%) of 14 eyes had no light perception visual acuity. No eye was phthisical or enucleated. CONCLUSIONS Green diode laser therapy can be an effective treatment for advanced Coats disease, even in the presence of a moderate to severely elevated retinal detachment.