Terry A. Cox

A computerized method of visual acuity testing: adaptation of the early treatment of diabetic retinopathy study testing protocol.

PURPOSE To develop a computerized method of visual acuity testing for clinical research as an alternative to the standard Early Treatment for Diabetic Retinopathy Study (ETDRS) testing protocol, and to evaluate its test-retest reliability and concordance with standard ETDRS testing. DESIGN Test-retest reliability study. METHODS Multicenter setting of a study population of 265 patients at three clinical sites. Visual acuity was measured with both the electronic visual acuity testing algorithm (E-ETDRS) and standard ETDRS protocol (S-ETDRS) twice on one eye of each patient. E-ETDRS testing was conducted using the electronic visual acuity tester (EVA), which utilizes a programmed Palm (Palm, Inc, Santa Clara, California, USA) hand-held device communicating with a personal computer and 17-inch monitor at a test distance of 3 meters. RESULTS For the E-ETDRS protocol, test-retest reliability was high (r = 0.99; with 89% and 98% of retests within 0.1 logMAR and 0.2 logMAR of initial tests, respectively) and comparable with that of S-ETDRS testing (r = 0.99; with 87% and 98% of retests within 0.1 logMAR and 0.2 logMAR of initial test, respectively). The E-ETDRS and S-ETDRS scores were highly correlated (r = 0.96 for initial tests and r = 0.97 for repeat tests). Based on estimates of 95% confidence intervals, a change in visual acuity of 0.2 logMAR (10 letters) from a baseline level is unlikely to be related to measurement variability using either the E-ETDRS or the S-ETDRS visual acuity testing protocol. CONCLUSIONS The E-ETDRS protocol has high test-retest reliability and good concordance with S-ETDRS testing. The computerized method has advantages over the S-ETDRS testing in electronically capturing the data for each tested letter, requiring only a single distance for testing from 20/12 to 20/800, potentially reducing testing time, and potentially decreasing technician-related bias.

Intraocular lens implantation in the absence of capsular support: a report by the American Academy of Ophthalmology.

OBJECTIVE This review was conducted to determine the safety and efficacy of open-loop anterior chamber, scleral-sutured posterior chamber, and iris-sutured posterior chamber intraocular lenses (IOLs) in eyes with inadequate capsular support for posterior chamber implantation in the capsular bag or ciliary sulcus. It also attempted to determine whether there is a preferred IOL or fixation site of choice in eyes with inadequate capsular support. METHODS A literature search conducted for the years 1980 to 2001 yielded 189 citations related to IOL implantation in the absence of capsular support. An update search, conducted in March 2002, yielded an additional 28 articles. The Anterior Segment Panel members reviewed these abstracts and selected 148 articles of possible clinical relevance for review. Of these, 89 were considered sufficiently clinically relevant for the panel methodologist to review and rate according to the strength of evidence. A level I rating was assigned to properly conducted, well-designed, randomized clinical trials; a level II rating was assigned to well-designed cohort and case-control studies; and a level III rating was assigned to case series. Articles comparing the safety and efficacy of the IOL type and fixation site were further evaluated for the quality of the statistical methods used in the study. Studies with a rating of A or B were considered acceptable, C was borderline, and D and F were considered unacceptable as medical evidence. RESULTS Forty-three articles with data concerning outcome of IOL insertion in eyes with inadequate capsular support had an evidence rating of level III or higher and were used in the final review of the safety and efficacy of one or more lens types and/or fixation sites. Seven articles had data about more than one lens type. Six had a statistical method rating of C or higher and were used to evaluate differences in visual outcomes and complication rates between lens types and fixation sites. CONCLUSIONS The literature supports the safe and effective use of open-loop anterior chamber, scleral-sutured posterior chamber, and iris-sutured posterior chamber IOLs for the correction of aphakia in eyes without adequate capsular support for placement of a posterior chamber lens in the capsular bag or ciliary sulcus. At this time, there is insufficient evidence to demonstrate the superiority of one lens type or fixation site. Precise determination of small differences in visual outcome or complication rates will require a large prospective, randomized clinical trial.

Pars plana vitrectomy, subretinal injection of tissue plasminogen activator, and fluid–gas exchange for displacement of thick submacular hemorrhage in age-related macular degeneration☆

PURPOSE To evaluate a new procedure for displacement of large, thick submacular hemorrhage in patients with age-related macular degeneration. METHODS Retrospective review of 11 eyes of 11 patients with age-related macular degeneration and thick submacular hemorrhage (defined as causing retinal elevation detectable on stereo fundus photographs) treated with vitrectomy, subretinal injection of tissue plasminogen activator (25 or 50 microg), and fluid-gas exchange with postoperative prone positioning. Outcome measures included displacement of hemorrhage from the fovea, best postoperative visual acuity, and final postoperative visual acuity. RESULTS In the 11 affected eyes of 11 patients (seven men and four women; mean age, 76 years), preoperative visual acuity ranged from 20/200 to hand motions. With surgery, subretinal hemorrhage was displaced from the fovea in all 11 cases. Mean postoperative follow-up was 6.5 months (range, 1 to 15 months). Best postoperative visual acuity varied from 20/30 to 5/200, with improvement in nine (82%) cases and no change in two cases. Eight eyes (73%) measured 20/200 or better, with four of these eyes (36%) 20/80 or better. Final postoperative visual acuity ranged from 20/70 to light perception, with improvement in eight (73%) cases, no change in one case, and worsening in two cases. A statistically significant difference was found between preoperative and best postoperative visual acuity (P =.004) but not between preoperative and final visual acuity (P =.16). Hemorrhage recurred in three (27%) eyes, causing severe visual loss in one eye. CONCLUSIONS This technique displaces submacular hemorrhage from the fovea and can improve vision in patients with age-related macular degeneration. However, recurrence of hemorrhage occurred in 27% of eyes and caused severe visual loss in one eye. A randomized, prospective clinical trial is necessary to determine the efficacy of this technique in comparison with other proposed treatments.

The Ahmed Valve in refractory pediatric glaucoma

PURPOSE To evaluate the efficacy of the Ahmed Glaucoma Valve implant in pediatric patients with refractory glaucoma. METHODS A retrospective chart review was conducted of 27 eyes from 23 consecutive pediatric patients (younger than 18 years) with refractory glaucoma treated with Ahmed Glaucoma Valve implant placement. The main outcome measure was time after surgery without failure. Success was defined as an intraocular pressure of 21 mm Hg or less without visually devastating complications or additional glaucoma surgery (exclusive of tube revision). Previous cycloablation, which was present in a subset of eyes, was examined as a possible influence on postoperative intraocular pressure control, glaucoma medication dependence, and surgical success. RESULTS The median patient age was 4.8 years (range, 0.3 to 16.8 years), with a follow-up of 3 to 31 months (mean, 12.6 +/- 8.2 months). Intraocular pressure was reduced from a preoperative mean of 32.8 +/- 7.5 mm Hg to 16.7 +/- 5.4 mm Hg at 18 months postoperatively, with an overall success rate of 85.2% at last follow-up. Cumulative probabilities of success by Kaplan-Meier analysis were 90.6% at 12 months and 58.3% at 24 months. Compared with those that did not undergo previous cycloablation, eyes that had undergone previous cycloablation had a lower mean postoperative intraocular pressure at 3- and 6-month follow-up (P < .001 and P = .057, respectively) and required fewer glaucoma medications at postoperative examination time points up to 18 months (P < or = .01 at each time point). Fifteen eyes (56%) required glaucoma medications after surgery. The most common complication was corneal-tube contact, which occurred in five eyes (18.5%). One eye with a wound leak required anterior chamber reformation. Retinal detachment occurred in one aphakic eye 2 years postoperatively, resulting in loss of vision. One eye with neovascular glaucoma required enucleation after an enlarging (presumably preexisting) medulloepithelioma was discovered. CONCLUSIONS Ahmed Glaucoma Valve implantation is a useful therapy for the treatment of refractory pediatric glaucoma, and it may be safely used in a subgroup of eyes with uncontrolled intraocular pressure despite previous cycloablation procedures.

Automated perimetry: A report by the American academy of ophthalmology

OBJECTIVE The purpose of this document is to summarize and evaluate the effectiveness of new automated perimetry tests and algorithms in diagnosing glaucoma and detecting disease progression. METHODS A literature search on automated perimetry retrieved over 300 citations from 1994 to 2001, of which 71 were selected as relevant to this assessment. The quality of the evidence obtained from these studies was assessed by the methodologist. RESULTS The four automated perimetry techniques described in this assessment are short wavelength automated perimetry (SWAP), frequency doubling technology perimetry (FDT), high-pass resolution perimetry (HPRP), and motion automated perimetry (MAP). The algorithms described are Swedish interactive threshold algorithm (SITA) and SITA fast. With the exception of SWAP, these techniques and algorithms reduce testing time and inconsistent patient performance when compared with conventional full threshold testing. CONCLUSIONS Short wavelength automated perimetry detected visual field loss earlier than standard threshold automated perimetry, with a sensitivity and specificity of about 88% and 92% respectively. However, it is a lengthy, demanding test, is sensitive to media opacities, and has a greater magnitude of long-term fluctuation compared with standard threshold automated perimetry, which make it difficult to assess disease progression accurately. When compared to standard threshold automated perimetry, FDT perimetry showed sensitivity and specificity greater than 97% for detecting moderate and advanced glaucoma, and sensitivity of 85% and specificity of 90% for early glaucoma. As FDT perimetry has a short testing time and is resistant to blur and pupil size, it may be a useful screening tool. In a longitudinal study, high-pass resolution perimetry was more effective than standard threshold automated perimetry in monitoring progressive glaucomatous loss, detecting progression at a median of 12 months earlier in 54% of patients studied. Motion automated perimetry demonstrated usefulness in detecting early glaucomatous visual loss in a longitudinal study. Studies on SITA demonstrated greater sensitivity and reproducibility and less intertest variability when compared to standard full threshold testing and a 50% reduction in testing times. A study comparing standard full threshold, SITA, and SITA fast found a sensitivity of 95% for the first two techniques and 93% for SITA fast. Long-term follow-up studies are needed to assess the ability of these techniques to detect progression of glaucoma over time.

Mitomycin C-augumented trabeculectomy with postoperative wound modulation in pediatric glaucoma.

PURPOSE The purpose of this study was to evaluate mitomycin C-augmented trabeculectomy combined with postoperative subconjunctival 5-fluorouracil and laser suture lysis in the treatment of refractory pediatric glaucoma. METHODS Twenty-one consecutive cases (17 patients) with refractory pediatric glaucoma treated with mitomycin C trabeculectomy (0.4 mg/mL for 3 to 5 minutes) and postoperative 5-fluorouracil, laser suture lysis, or both were retrospectively reviewed. Success was defined as intraocular pressure between 4 and 16 mm Hg without further glaucoma surgery or devastating complication. RESULTS The median age of the study population was 2.6 years (range, 0.05 to 16 years). The overall success rate was 52.4%, with a median follow-up of 23 months for successful cases. Success rates for patients older than 1 year of age versus those younger than 1 year of age at surgery were 73% and 30%, respectively. Success rates for phakic versus aphakic eyes were 64% and 29%, respectively. Age and lens status, taken together, were significant predictors of outcome (P = .013). Reasons for failure in this study were uncontrolled intraocular pressure (8 cases), persistent wound leak (1 case), and endophthalmitis (1 case); the latter 2 cases required bleb excision. Other complications encountered included chorioretinal detachment, shallow anterior chamber, 5-fluorouracil toxicity, and cataract formation. No irreversible visual deficits could be attributed to the trabeculectomy procedure or subsequent complications in any of these cases. CONCLUSIONS Mitomycin C-augmented trabeculectomy combined with postoperative suture lysis and 5-fluorouracil is a viable option for older phakic children with refractory glaucoma. This procedure has a lower success rate in infants and in aphakic eyes. Both early and late postoperative complications are common, and diligent lifelong long-term follow-up is needed to detect bleb leaks and infection. The addition of postoperative suture lysis and 5-fluorouracil to mitomycin C-augmented trabeculectomy did not provide any convincing improvement in the success of this procedure in pediatric patients with refractory glaucoma and may have increased the complication rate.

A clinical comparison of transscleral cyclophotocoagulation with neodymium: YAG and semiconductor diode lasers

PURPOSE To compare the efficacy of transscleral cyclophotocoagulation using a neodymium: YAG (Nd:YAG) or semiconductor diode laser in controlling intraocular pressure in patients with refractory glaucoma. METHODS In a prospective study, 95 eyes of 91 patients with refractory glaucoma randomly received Nd:YAG or diode cyclophotocoagulation. Patients were followed for a mean of 10.4 months (10.42 +/- 3.16, mean +/- SD). We compared available data preoperatively and at 1 week, 1 month, 6 months, and 12 months postoperatively. Data analyzed were corrected visual acuity, intraocular pressure, and the type of glaucoma. RESULTS There was a statistically significant decrease in intraocular pressure after both Nd:YAG and diode cyclophotocoagulation at each time period. However, there were no significant differences in postoperative intraocular pressure or visual acuity change between Nd:YAG and diode procedures. CONCLUSIONS Compared with the Nd:YAG laser for transscleral cyclophotocoagulation, the diode laser has technological advantages including portability, durability, and smaller size, while providing equivalent postoperative intraocular pressure and visual acuity change.

Diagnostic yield of vitrectomy in eyes with suspected posterior segment infection or malignancy

PURPOSE To determine the yield of diagnostic pars plana vitrectomy in eyes with suspected posterior segment inflammation or malignancy when clinical examination and systemic laboratory testing did not yield a specific diagnosis. DESIGN Non-comparative interventional case series PARTICIPANTS Eighty-seven consecutive patients (90 eyes) who underwent diagnostic pars plana vitrectomy from 1989 through 1999. INTERVENTIONS Vitreous samples were analyzed in a directed manner based on the preoperative clinical examination and systemic laboratory testing. MAIN OUTCOME MEASURES Diagnosis from each test performed on the vitreous samples. RESULTS Diagnostic vitrectomy was performed alone in 6 eyes (7%) and as part of a therapeutic procedure in the remaining 84 eyes. The diagnostic tests performed most frequently included cytopathology (83%), microbiologic culture and sensitivity (43%), polymerase chain reaction (PCR) (36%), and intraocular antibody levels for T. canis (14%). Of these, intraocular antibody testing and PCR had the highest positive yield, 46% and 39%, respectively. Overall, directed vitreous analysis identified a specific cause in 35 eyes (39%). Of the 65 cases in which an underlying infection was suspected preoperatively, the procedure yielded a specific diagnosis in 27 (42%). When intraocular malignancy was considered preoperatively (71 eyes), a diagnosis of intraocular lymphoma was obtained in seven (10%). This difference between these diagnostic yields was significant (P = 0.02, Fishers exact test). CONCLUSIONS Diagnostic vitrectomy with directed vitreous fluid analysis yields a specific cause and guides subsequent therapy in a high percentage of cases. This procedure is a valuable adjunct in cases that cannot be diagnosed by less invasive methods.

Condensation on Polymethylmethacrylate, Acrylic Polymer, and Silicone Intraocular Lenses after Fluid-Air Exchange in Rabbits

PURPOSE Condensation occurs rapidly on silicone intraocular lenses (IOLs) after vitrectomy and fluid-air exchange in the presence of a posterior capsulotomy, severely limiting the retinal view. Foldable IOLs made of an acrylic polymer are now available. The authors compare the condensation and subsequent retinal view degradation after vitrectomy and fluid-air exchange in rabbit eyes implanted with polymethylmethacrylate (PMMA), soft acrylic polymer (ACRYSOF), and silicone IOLs. METHODS Thirty rabbits underwent bilateral lens removal. Twenty PMMA, 20 acrylic polymer, and 20 silicone IOLs were implanted into the capsular bag. After three-port vitrectomy, eyes were randomly assigned to undergo a posterior capsulotomy or to an intact posterior capsule. Fluid-air exchange was performed, and the amount of condensation on the IOL surface and resultant retinal view was graded. Surgical maneuvers then were performed to decrease the condensation. These maneuvers included wiping the IOL surface with a soft-tipped cannula and coating it with viscoelastic. RESULTS No condensation occurred on IOLs in eyes with an intact posterior capsule. Significantly more condensation occurred on IOLs in eyes with a capsulotomy, regardless of IOL type (P < 0.014). Wiping the condensation resulted in significantly less condensation and improved retinal view on the PMMA and acrylic IOLs when compared with the silicone IOLs (P < 0.024). Condensation was eliminated on all three IOL types after viscoelastic was applied. However, increased distortion of the retinal view was induced by the viscoelastic on the silicone IOL as compared with the other IOLs. CONCLUSIONS Condensation and subsequent retinal image degradation occurs uniformly after vitrectomy, posterior capsulotomy, and fluid-air exchange in eyes with PMMA, acrylic, and silicone IOLs. Because the condensation can be eliminated most easily on acrylic IOLs compared with silicone IOLs, when foldable IOL techniques are used it is likely that an acrylic polymer IOL would be advantageous for those patients at risk for future vitreous procedures requiring fluid-air exchange.

Intracameral anesthesia: A report by the American Academy of Ophthalmology

OBJECTIVE This document describes the technique of intracameral anesthesia and examines the available evidence to address questions about its effectiveness, possible corneal endothelial and retinal toxicity, and the optimal and maximal dose. METHODS A literature search conducted for the years 1968 to 2000 retrieved over 180 citations that matched the search criteria. Panel members and a methodologist reviewed this information, and it was evaluated for the quality of the evidence presented. RESULTS Some studies report effectiveness of intracameral anesthesia while others report no effect. In those studies showing an effect, levels of pain in the groups that were compared were low. Short-term studies seem to indicate that preservative (methylparaben)-free lidocaine 1% is well tolerated by the corneal endothelium but that higher concentrations of lidocaine are toxic. There is some evidence of electroretinogram changes after exposure to lidocaine or bupivacaine. CONCLUSIONS The ideal timing and placement of intracameral anesthesia has not been determined. Because topical anesthesia alone is effective, surgeons may elect to use intracameral anesthesia for incremental pain control in patients who cannot be adequately managed with topical alone. Appropriate patient selection is important when using this method of anesthesia. While short-term studies seem to indicate safety, long-term effects are unknown. Patient preferences for anesthesia are not well studied.