Biomedical subjects

Stanley Chang

Publications and source records attributed to Stanley Chang.

At least 19 recordsLinked to original sources

PubMed2006

Diabetic vitrectomy: influence of lens status upon anatomic and visual outcomes.

OBJECTIVE: To determine the effect of lens status upon the anatomic and visual results in primary diabetic vitrectomy. DESIGN: Retrospective, comparative, consecutive case series. PARTICIPANTS: One hundred two eyes of 85 patients with proliferative diabetic retinopathy and its complications that underwent primary vitrectomy. METHODS: The eyes that remained phakic after vitrectomy were compared with the eyes that were either aphakic or pseudophakic (nonphakic) postoperatively. MAIN OUTCOME MEASURES: Intraoperative and postoperative complications, vitreoretinal reoperation rate, and ultimate anatomic and visual success with at least 6 months' follow-up. RESULTS: Preoperatively, 72 eyes were phakic, and 30 were aphakic (n = 1) or pseudophakic (n = 29). During vitrectomy, 1 eye underwent lensectomy and 12 eyes underwent phacoemulsification with lens implantation. Postoperatively, 59 eyes were phakic and 43 eyes were nonphakic. The vitreoretinal reoperation rate was significantly higher (P = 0.04) for the phakic group (28.8%) than for the nonphakic group (11.6%). Rubeosis iridis developed in 3 phakic eyes and no nonphakic eyes (P = 0.26). Intraoperative complications were similar in the phakic and nonphakic groups (P = 0.40). Postoperative complications such as rhegmatogenous retinal detachment (P = 0.39), nonclearing vitreous hemorrhage (P = 0.07), and anterior chamber complications (P = 0.60) were also similar. Visual acuity improved by at least 0.2 logarithm of the minimum angle of resolution units in 76.2% of the phakic eyes and 86.0% of the nonphakic eyes (P = 0.22). CONCLUSIONS: Eyes that were phakic after primary diabetic vitrectomy had a significantly higher subsequent vitreoretinal reoperation rate when compared with nonphakic eyes, suggesting that diabetic eyes are less likely to require additional vitreoretinal surgery if they are rendered nonphakic before or during vitrectomy.

Adult↗

PubMed2006

LXII Edward Jackson lecture: open angle glaucoma after vitrectomy.

PURPOSE: To present data and an hypothesis for the late development of open angle glaucoma (OAG) after vitrectomy. DESIGN: A retrospective observational case series. METHODS: The records of 453 eyes that had undergone vitrectomy were reviewed for postoperative OAG. Eyes with confounding factors were excluded. Sixty-eight eyes of 65 patients that underwent routine vitrectomy were followed for a mean of 56.9 months (range, seven to 192 months). For the main outcome measures, patients were classified into three groups: patients with suspected glaucoma, patients in whom glaucoma developed after the operation, and patients with pre-existing glaucoma. RESULTS: In glaucoma suspects, the mean intraocular pressure was significantly higher in the operated eye compared with the fellow eye (P = .0001). In eyes with new onset glaucoma, 23 of 34 eyes (67.6%) had it in the vitrectomized eye only. In phakic eyes, the time interval between vitrectomy and the development of glaucoma (mean, 45.95 months) was significantly longer than eyes that were nonphakic at the time of vitrectomy (mean, 18.39 months; P = .0115). When the interval between cataract surgery in phakic eyes to the development of glaucoma was compared with the interval from vitrectomy to glaucoma diagnosis in the nonphakic group, the difference was not statistically significant. In eyes with glaucoma before the operation, the mean number of antiglaucoma medications that were required to control the intraocular pressure was significantly higher in the vitrectomized eye, compared with the fellow eye (2.9 medications +/- 1.2 vs 2.0 medications +/- 1.4; P = .0215; n = 14). CONCLUSION: There is an increased risk of OAG after vitrectomy. The presence of the lens may be protective. In established OAG before the operation, the number of antiglaucoma medications may increase after surgery. Oxidative stress is hypothesized to have a role in the pathogenesis.

Adolescent↗

PubMed2006

Measurement of the actual dose of triamcinolone acetonide delivered by common techniques of intravitreal injection.

PURPOSE: To measure the actual dose of triamcinolone acetonide (TA) delivered during intravitreal injection performed by several common techniques. DESIGN: Experimental study. METHODS: A 0.1-ml, 40-mg vial of TA (Kenalog-40; Bristol-Myers-Squibb, Peapack, New Jersey, USA) was prepared according to one of four protocols and the mass determined after drying overnight on waxed paper. In group 1, a 0.1-ml aliquot of TA was dispensed with a 30-gauge needle after shaking the vial 10 or 30 times. Group 2 used a 27-gauge needle. In group 3, the supernatant was removed from the crystals. Group 4 passed the suspension through a 0.2-microm micropore filter and rinsed the crystals with saline. RESULTS: There was no statistically significant difference between 30- or 27-gauge needles (P = 0.83, t test) or between shaking the vial 10 or 30 times before withdrawing the drug (P = 0.99). A statistically significant difference (t test, P = 0.001) was found between TA delivered from the initial 60% of each syringe (mean +/- SD, 2.7 +/- 1.0 mg) to that drawn from the last 40% of each syringe (7.8 +/- 3.6 mg). Group 3 had a mean weight of 32.1 +/- 7.0 mg and group 4, 10.6 +/- 2.1 mg. CONCLUSIONS: Efforts to achieve a 4.0-mg dose of TA, regardless of method used, are variable and inconsistent. Injecting through a small-gauge needle appears to concentrate the remaining suspension. Techniques to concentrate TA or remove aqueous preservatives by filtering effectively increase the concentration, but these results are variable.

Filtration↗

PubMed2006

Predictive value of fundus autofluorescence for development of geographic atrophy in age-related macular degeneration.

PURPOSE: It has been suggested that lipofuscin accumulation, as measured by increased fundus autofluorescence (FAF), precedes progression or development of junctional zone geographic atrophy (GA) in age-related macular degeneration (AMD). The tools of biomedical image analysis were used to measure the probabilistic relationship of GA progression to increased FAF. METHODS: Serial AF images of eight eyes of six patients with AMD with GA were registered on computer. The images were leveled with a 12-zone quadratic polynomial mathematical model to minimize background variability. Semiautomated segmentation of GA was performed on the leveled images. Increased FAF was defined as a gray level greater than 2 standard deviations above the leveled image mean, identified on the initial image with automated segmentation, and measured as a fraction of the 250-microm border zone surrounding the initial GA lesion. Areas of GA lesions were identified on the final image. The positive predictive value (PPV) of increased FAF was determined as the probability that any pixel with increased FAF in the initial image would become part of new GA in the final image. Relative PPV was determined relative to the total quantity of new GA. The NPV (NPV) of increased FAF was calculated as the probability that any pixels without increased FAF would not become atrophic. The relative NPV was determined similarly. A similar analysis was also conducted with a 500-microm border zone to determine the predictive value of proximity to the original GA lesion ("proximity") for GA progression. RESULTS: As a fraction of the geographic atrophy border zone, the mean new GA was 0.44+/-0.20, and the mean increased FAF was 0.06+/-0.06. The mean PPV of increased FAF for new GA formation was 0.50+/-0.26. Compared with the relative PPV of chance of 1.0, the mean relative PPV of increased FAF was 1.15+/-0.28. The mean NPV of increased FAF was 0.57+/-0.20. The mean relative NPV of increased FAF was 1.00+/-0.02. In the 500-microm border zone, the mean relative PPV of FAF and of proximity were essentially equal (1.56+/-.70 and 1.52+/-0.26, respectively), whereas the mean relative NPV of proximity was significantly greater than that of FAF (1.26+/-0.19 and 1.01+/-0.01, respectively, P=0.02) CONCLUSIONS: The results of digital image analysis suggest that although increased FAF may have a modest PPV for new GA development, the relative PPV is generally no greater than chance. Similarly, the relative NPV demonstrates negligible difference from chance and is also lower than the relative NPV of proximity. This suggests that increased FAF, though a disease manifestation, is not a strong risk factor for development or extension of GA.

Aged↗

PubMed2005

Upregulation of RAGE and its ligands in proliferative retinal disease.

We sought to study the presence of the receptor for advanced glycation endproducts (RAGE) and its ligands, advanced glycation endproducts (AGEs), S100/calgranulins and amphoterin (high mobility group box 1 protein; HMGB1), in the vitreous cavity and epiretinal membranes (ERMs) of eyes of patients with proliferative diabetic retinopathy (PDR) and proliferative vitreoretinopathy (PVR). Undiluted vitreous specimens were collected from 30 eyes of 30 patients undergoing pars plana vitrectomy for repair of retinal detachment (RD) secondary to PDR (n = 15) or PVR (n = 15). The vitreous samples obtained from 10 eyes undergoing macular hole repair were used as controls. Epiretinal membranes were obtained from eight eyes with PDR and from 10 eyes with PVR. The levels of AGEs in the vitreous were measured using ELISA. The vitreous levels of soluble RAGE (sRAGE), S100/calgranulins and amphoterin were measured using Western blot analyses. The localization of RAGE and its ligands in ERMs was determined with immunohistochemistry. The vitreous levels of sRAGE were significantly increased in both PDR and PVR (p < or = 0.05) compared to control vitreous. In both PDR and PVR, the vitreous levels of AGEs (p < or = 0.01), S100/calgranulins (p < or = 0.05), and amphoterin (p < or = 0.01) were also elevated compared to control eyes. Expression of RAGE was detected in six of eight ERMs from eyes with PDR and eight of 10 ERMs from eyes with PVR. Many cells expressing RAGE also expressed vimentin, suggesting a glial cell origin. Ligands for RAGE were also detected in ERMs, with AGEs detected in five eyes with PDR and eight eyes with PVR. Similarly, S100 and amphoterin ERM expression was observed in six eyes with PDR; these ligands were also expressed in ERMs from eyes with PVR (8 and 7 cases, respectively). We conclude that RAGE and its ligands are increased in the vitreous cavity of eyes with PDR and PVR and are present in ERMs of eyes with these proliferative retinal disorders. These findings suggest a role for the proinflammatory RAGE axis in the pathogenesis of proliferative retinal diseases.

Adolescent↗

PubMed2005

A common haplotype in the complement regulatory gene factor H (HF1/CFH) predisposes individuals to age-related macular degeneration.

Age-related macular degeneration (AMD) is the most frequent cause of irreversible blindness in the elderly in developed countries. Our previous studies implicated activation of complement in the formation of drusen, the hallmark lesion of AMD. Here, we show that factor H (HF1), the major inhibitor of the alternative complement pathway, accumulates within drusen and is synthesized by the retinal pigmented epithelium. Because previous linkage analyses identified chromosome 1q25-32, which harbors the factor H gene (HF1/CFH), as an AMD susceptibility locus, we analyzed HF1 for genetic variation in two independent cohorts comprised of approximately 900 AMD cases and 400 matched controls. We found association of eight common HF1 SNPs with AMD; two common missense variants exhibit highly significant associations (I62V, chi2 = 26.1 and P = 3.2 x 10(-7) and Y402H, chi2 = 54.4 and P = 1.6 x 10(-13)). Haplotype analysis reveals that multiple HF1 variants confer elevated or reduced risk of AMD. One common at-risk haplotype is present at a frequency of 50% in AMD cases and 29% in controls [odds ratio (OR) = 2.46, 95% confidence interval (1.95-3.11)]. Homozygotes for this haplotype account for 24% of cases and 8% of controls [OR = 3.51, 95% confidence interval (2.13-5.78)]. Several protective haplotypes are also identified (OR = 0.44-0.55), further implicating HF1 function in the pathogenetic mechanisms underlying AMD. We propose that genetic variation in a regulator of the alternative complement pathway, when combined with a triggering event, such as infection, underlie a major proportion of AMD in the human population.

Aged↗

PubMed2005

Removal of the intruding Miragel's scleral buckle by pars plana ultrasonic fragmentation.

PURPOSE: To introduce a surgical approach for removing intruded scleral buckle resulting from Miragel's implant. DESIGN: Interventional case report. METHODS: After cutting and releasing scleral band externally, a pars plana Fragmatome was used to break up and aspirate pieces of the Miragel's implant that had grown into the eye, filling the vitreous cavity. RESULTS: The intruding Miragel's buckle was shaved to the plane of the retina without any complication. The retina was completely attached. CONCLUSION: Use of ultrasonic fragmentation by a pars plana approach was effective in removing the intavitreally expanded buckling element without harming the retina.

Aged↗

PubMed2005

Cataract progression after intravitreal triamcinolone injection.

PURPOSE: To assess cataract progression after intravitreal triamcinolone injection. DESIGN: Retrospective, interventional, case-control study. METHODS: Forty-two phakic eyes of 37 patients were injected one, two, or three times with intravitreal triamcinolone for various indications. Noninjected phakic fellow eyes served as the control. The mean follow-up time for single injection was 12 months, for multiple injections was 14 months, and for control group was 13 months. Lens status, best-corrected visual acuity, and refractive errors were recorded at baseline and at each follow-up examination. RESULTS: At the last follow-up, changes in posterior subcapsular cataract and refractive error from baseline were significantly different between single triamcinolone-injected eyes and the control group [0.7 +/- 0.2 (mean +/- SEM [arbitrary unit] vs 0.2 +/- 0.1, P = .02; and -0.5 +/- 0.1 diopter vs -0.2 +/- 0.1 diopter, P = .01, respectively). For multiple-injected eyes and control eyes, change from baseline in corticonuclear cataract (1.1 +/- 0.2 vs 0.2 +/- 0.1), posterior subcapsular cataract (1.1 +/- 0.2) and refractive error (-1.8 +/- 0.4 diopters) were significantly different (P < .001, P < .001, and P < .001, respectively). Visual acuity did not change after single injection (P = .83) and in control group (P = .19) but decreased after multiple injections (P = .006). Eleven study eyes and two control group eyes underwent cataract extraction during study period. Corticonuclear and posterior subcapsular cataract progression significantly correlated with follow-up time (P = .003 and P = .02, respectively) and number of injections (P = .01 and P = .04, respectively). CONCLUSIONS: Single intravitreal triamcinolone injection induces posterior subcapsular cataract development, whereas multiple injections result in all-layer cataract progression.

Aged↗

PubMed2005

Influence of relaxing retinotomy on surgical outcomes in proliferative vitreoretinopathy.

PURPOSE: This study sought to determine the influence of relaxing retinotomy (RR) incisions upon surgical outcomes in the repair of recurrent retinal detachment (RD) attributable to proliferative vitreoretinopathy (PVR). DESIGN: Retrospective, consecutive, nonrandomized, single-center series. METHODS: Eighty-one eyes with recurrent RD attributable to PVR were retrospectively reviewed. Exclusion criteria were giant retinal tear, uveitis, trauma, proliferative diabetic retinopathy, and age under 18 years. A total of 52 eyes underwent RR at the time of surgery (64.2%); 29 eyes were repaired without this technique. Perfluorocarbon gas (n = 34) or silicone oil (n = 47) was used as postoperative tamponade. Statistical analyses were performed using the Fisher exact test. RESULTS: Eyes that received RR had significantly higher rates of anterior PVR (P = .009). Eyes receiving silicone oil for postoperative tamponade had worse baseline characteristics compared with those receiving gas. The use of RR in eyes receiving gas tamponade had no marked influence on the initial anatomic outcomes, with recurrent retinal detachment occurring in five of 14 eyes that received an RR and seven of 20 eyes that did not receive an RR (P = .62). Eyes in which silicone oil was used as a postoperative tamponade had a significantly lower rate of recurrent RD requiring additional surgery when RR was employed (one of 38 eyes) when compared with eyes that did not receive an RR (three of nine eyes, P = .02). Ultimately, surgical reattachment was attained in all eyes except one. Eyes that received gas tamponade without RR had significantly better median vision (P = .008). CONCLUSIONS: Surgical management of PVR often results in ultimate retinal reattachment. An RR incision does not appear to influence initial anatomic repair when gas tamponade is used after vitrectomy surgery for PVR. However, RR may increase the initial surgical success rate in eyes receiving silicone oil tamponade for PVR. In eyes undergoing RR for the treatment of severe PVR, the use of silicone oil may increase the initial rate of reattachment compared with the use of gas tamponade.

Adult↗

PubMed2005

Management of severe hypotony with intravitreal injection of viscoelastic.

PURPOSE: To investigate the effect of an intravitreal injection of sodium hyaluronate 1.4% and 2.3% in the treatment of hypotony. DESIGN: Interventional case series. METHODS: Intravitreal injection of sodium hyaluronate 1.4% was performed to treat persistent hypotony in three eyes after the successful repair of retinal detachment and in one eye with uveitis. Injection of sodium hyaluronate 2.3% was performed in one eye after the successful repair of retinal detachment with removal of silicone oil. RESULTS: At the last follow-up examination (2-16 months), intraocular pressure increased to at least 5 mm Hg (5-14 mm Hg) in all eyes that had been injected with sodium hyaluronate. Intraocular pressure increased to 38 mm Hg in the eye that had been injected with sodium hyaluronate 2.3% on postoperative day 1 and was 10 mm Hg at three months. Vision improved in all patients. CONCLUSION: Intraocular injection of sodium hyaluronate 1.4 and 2.3% appears to be efficacious in reversing hypotony in some eyes. Functional and structural findings can also improve.

Aged↗

PubMed2005

Apoptosis and cell proliferation in proliferative retinal disorders: PCNA, Ki-67, caspase-3, and PARP expression.

PURPOSE: To assess the incidence of cell proliferation and apoptosis in epiretinal membranes from eyes with proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy (PDR), and macular pucker (MP) and to further investigate the potential involvement of key executors of apoptosis. METHODS: Epiretinal membranes were obtained from the eyes of 23 patients who underwent vitrectomy surgery for recurrent retinal detachment due to PVR (n = 16), traction retinal detachment due to PDR (n = 5), and macular pucker (n = 2). Cell proliferation was evaluated by Ki-67 and PCNA (proliferation cell nuclear antigen) immunostaining. Apoptosis was assessed by TUNEL (terminal deoxynucleotidyl transfrase-dUTP-nick end labeling). The expression of caspase-3 and PARP (poly-ADP-ribose-polymerase) was detected using antibodies against activated caspase-3 and p85 fragment of PARP. Cytokeratin and activated caspase-3/PARP, GFAP (glial fibrillary acidic protein) and activated caspase-3/PARP double staining were used to identify cell types in the membranes. RESULTS: There was no statistically significant difference in the cell proliferative index between PVR (70.1 +/- 4.2%), PDR (82.1 +/- 7.0%), and macular pucker (72.9 +/- 22.8%) by multivariate analysis (p = 0.39, ANOVA) and univariate analysis. Apoptotic nuclei were seen more frequently in chronic retinal detachments of greater than 2 months duration, but the difference, compared to shorter term retinal detachments was not statistically significant (p = 0.19). The apoptosis indices determined for PVR (2.3 +/- 0.7%), PDR (3.4 +/- 1.5%) and macular pucker (5.5 +/- 3.2%) were not significantly different (ANOVA, p = 0.41). Apoptotic nuclei were correlated, increased with expression of caspase-3 and PARP. Many apoptotic cells appeared to derive from retinal pigment epithelium cells. CONCLUSIONS: Cell proliferation and apoptosis appear to be key mechanisms regulating certain cell populations in epiretinal membranes of PVR, PDR, and macular pucker. Inhibition of proliferative regulators such as PCNA and/or activation of apoptotic executors such as caspase-3 may serve as therapeutic targets to halt progression of proliferative retinal disorders.

Adult↗

PubMed2004

Autofluorescence as a novel approach to diagnosing macular holes.

PURPOSE: To report the capability of autofluorescence as a novel approach to diagnosing macular holes. DESIGN: Observational case report. METHODS: In an institutional study, autofluorescence photos and optical coherence tomography scans of two patients who had surgery for macular holes were reviewed. RESULTS: Macular hole cases had a strong subfoveal autofluorescence signal, which disappeared after surgical closure of the macular hole. CONCLUSIONS: Autofluorescence is a novel approach to demonstrating a macular hole. This technique can also be used to confirm postoperative outcome after macular hole repair. A lack of autofluorescence corresponds to macular hole closure.

Aged↗

PubMed2004

Measurement of retinal thickness by ocular coherence tomography in a case of scleral transparency in high myopia.

PURPOSE: Staphylomatous thinning of the sclera and retina are among the numerous changes associated with the elongated eye of high myopia. We report a case of scleral and retinal transparency in high myopia in which ocular coherence tomography was used to measure retinal and scleral thickness in vivo. DESIGN: Observational case report. METHODS: The clinical presentation and evaluation of a case of scleral transparency in high myopia are presented. RESULTS: This case demonstrates numerous anatomical changes to the sclera and retina known to occur in association with high myopia. Initial evaluation by optical coherence tomography demonstrated a retinal thickness of 74 microm and a scleral thickness of 80 microm. CONCLUSIONS: Optical coherence tomography can be used to measure scleral and retinal thickness in vivo in a patient with high myopia. It is not known at this time what precautions are necessary in such a patient should intraocular surgery be required.

Body Weights and Measures↗

PubMed2004

Familial idiopathic macular hole.

PURPOSE: To report macular hole formation among siblings within four families. DESIGN: Observational case series. METHODS: Four families were identified who had macular holes among siblings from within three multiphysician tertiary-care referral retina practices. RESULTS: In the first family, two sisters in their seventh decade developed Stage 2 macular holes requiring surgical intervention; two male siblings were unaffected. In a second family, three of four siblings were affected, including one brother with a Stage 4 macular hole, one sister with a Stage 3 macular hole, and a third sister with a lamellar macular hole. In a third family, two siblings (one man, one woman) developed macular holes within 1 year of each other. Three years later, the male sibling developed a macular hole in the fellow eye. In the last family, twin sisters developed macular holes (unilateral in one sister, bilateral in the other), and their deceased father may also have had bilateral macular holes. CONCLUSIONS: The occurrence of macular holes in these four sets of siblings suggests a possible genetic component in the formation of macular holes in these individuals.

Aged↗

PubMed2004

Oxygen tension in the rabbit lens and vitreous before and after vitrectomy.

Oxygen is believed to be one of the potential causative agents for the development of nuclear cataract following vitrectomy. The aim of this study was to determine the partial pressure of oxygen (pO2) in different compartments of the rabbit eye, and to describe the changes following vitrectomy. Twenty-six rabbits (3.5-5.3 kg) were anesthetized and oxygen tension was probed using a fiber-optic oxygen sensor system (optode). A micromanipulator was employed to ascertain the exact position of the probe within the eye. Measurements were taken pre- and post-vitrectomy at several defined positions within the vitreous, the lens and the anterior chamber. Follow-up measurements were performed 2 and 8 weeks after vitrectomy. The contralateral eye served as a control. Measurements in the normal rabbit eye showed that oxygen tension in the globe is asymmetrical with the lowest pO2 in the nucleus of the lens (10.4 mmHg+/-3.0). The region of the lens near the posterior capsule has an oxygen tension close to the values of the vitreous directly behind the posterior capsule (12.4 mmHg+/-3.1). The highest pO2 within the posterior compartment of the eye was measured close to the retinal surface (40-l60 mmHg) depending on neighboring large vessels. The tension drops off rapidly to 20 mmHg some 0.5 mm from the retina. From that position to the posterior surface of the lens there is a shallow gradient of decreasing pO2. Immediately following vitrectomy the pO2 in the BSS replacement varied from ca. 90-140 mmHg, and decreased over approximately 30 min. to levels that were 2-3 times that of normal vitreous. Two weeks after vitrectomy the pO2 values in the lens were 2-3 times as high as in the control eye (p < 0.05). In addition there is no longer a gradient in the vitreous cavity, except close to the retina. Eight weeks after vitrectomy, pO2 levels in the lens were decreased but still remained higher than in the normal eye (13.83 mmHg+/-0.02). The pO2 gradient in the vitreous was not detectable anymore. Overall the results provide evidence that oxygen levels in the lens increase significantly after vitrectomy in rabbits. If this occurs in humans it may contribute to cataract formation following surgery.

Animals↗

PubMed2004

The influence of the full moon on seizure frequency: myth or reality?

To investigate a possible relationship between seizure frequency and the lunar cycle, we reviewed the occurrence of seizures recorded in our epilepsy monitoring unit over a 3-year period. Analysis of the total number of seizures (epileptic plus nonepileptic) showed no significant association. A separate analysis revealed that for nonepileptic seizures, there was an increase at the full moon, and for epileptic seizures, an increase in the last quarter. We conclude that there is no "full moon" effect on seizures as a whole, although there is a possible effect on nonepileptic seizures.

Chi-Square Distribution↗

PubMed2004

Evolving guidelines for intravitreous injections.

Intravitreous (i.v.t.) injection is increasingly being incorporated into the management of ocular diseases. While only fomivirsen sodium (Vitravene) is currently approved by the Food and Drug Administration as an i.v.t. injection, the number of approved i.v.t. injections indications is anticipated to grow on the basis of promising results from ongoing clinical studies. Despite the potential benefits that may be derived from intraocular injections of different agents, no guidelines have been published previously for i.v.t. injection. The purpose of this document is to identify specific strategies for the delivery of i.v.t. injection that may reduce risks and improve outcomes. Consensus was sought among a panel of investigators, surgeons experienced with this technique, and industry representatives. Objective evidence was sought for all guidelines, but consensus was accepted where evidence remains incomplete. In the absence of either evidence or consensus, the current manuscript identifies outstanding issues in need of further investigation. It is anticipated that more complete guidelines will evolve over time, potentially altering some of the guidelines included here, based on new applications of i.v.t. injection, additional clinical experience, and results of clinical trials.

Humans↗

PubMed2003

Continuous outflow devices for macular translocation with 360-degree retinotomy.

PURPOSE: Separation of the retina from retinal pigment epithelium is the most difficult step in macular translocation surgery. To complete this critical step, we have developed two specially designed continuous outflow needles, a rigid needle for creating retinal detachment and a liquid perfluorocarbon injection needle with a soft tip. DESIGN: Experimental study, new instrument development. METHODS: To permit continuous outflow during separation of the retina from the retinal pigment epithelium, the shaft of the continuous outflow needle is smaller than 20 gauge in diameter to allow continuous flow of fluid from the vitreous cavity. RESULTS: These instruments have been used successfully in 54 eyes that underwent macular translocation with 360-degree retinotomy. The rigid needle creates safe retinal detachment by keeping intraocular pressure lower, which is strictly needed for this step. The injection needle facilitates injection of perfluorocarbon liquid while manipulating the retina gently with its soft tip. CONCLUSION: Continuous outflow instruments are useful tools because they facilitate critical steps in the delicate process of macular translocation surgery.

Choroidal Neovascularization↗