Cynthia Mattox

Optical Coherence Tomography Measurement of Macular and Nerve Fiber Layer Thickness in Normal and Glaucomatous Human Eyes

PURPOSE To evaluate the hypothesis that macular thickness correlates with the diagnosis of glaucoma. DESIGN Cross-sectional study. PARTICIPANTS We studied 367 subjects (534 eyes), including 166 eyes of 109 normal subjects, 83 eyes of 58 glaucoma suspects, 196 eyes of 132 early glaucoma patients, and 89 eyes of 68 advanced glaucoma patients. METHODS We used optical coherence tomography (OCT) to measure macular and nerve fiber layer (NFL) thickness and to analyze their correlation with each other and with glaucoma status. We used both the commercial and prototype OCT units and evaluated correspondence between measurements performed on the same eyes on the same days. MAIN OUTCOME MEASURE Macular and NFL thickness as measured by OCT. RESULTS All NFL parameters both in prototype and commercial OCT units were statistically significantly different comparing normal subjects and either early or advanced glaucoma (P < 0.001). Inner ring, outer ring, and mean macular thickness both in prototype and commercial OCT devices were found to be significantly different between normal subjects and advanced glaucomatous eyes (P < 0.001). The outer ring was the only macular parameter that could significantly differentiate between normal and early glaucoma with either the prototype or commercial OCT unit (P = 0.003, P = 0.008, respectively). The area under the receiver operator characteristic (AROC) curves comparing mean NFL thickness between normal and advanced glaucomatous eyes was 1.00 for both the prototype and commercial OCT devices for eyes scanned on both machines on the same day. The AROC comparing mean macular thickness in normal and advanced glaucomatous eyes scanned on both machines on the same day was 0.88 for the prototype OCT device and 0.80 for the commercial OCT. CONCLUSIONS Both macular and NFL thickness as measured by OCT showed statistically significant correlations with glaucoma, although NFL thickness showed a stronger association than macular thickness. There was good correspondence between findings using both the prototype and commercial OCT units. Macular and NFL thickness measurements made with OCT may have usefulness in the clinical assessment of glaucoma.

Evaluation of focal defects of the nerve fiber layer using optical coherence tomography

OBJECTIVE To analyze glaucomatous eyes with known focal defects of the nerve fiber layer (NFL), relating optical coherence tomography (OCT) findings to clinical examination, NFL and stereoscopic optic nerve head (ONH) photography, and Humphrey 24-2 visual fields. DESIGN Cross-sectional prevalence study. PARTICIPANTS The authors followed 19 patients in the study group and 14 patients in the control group. INTERVENTION Imaging with OCT was performed circumferentially around the ONH with a circle diameter of 3.4 mm using an internal fixation technique. One hundred OCT scan points taken within 2.5 seconds were analyzed. MAIN OUTCOME MEASURES Measurements of NFL thickness using OCT were performed. RESULTS In most eyes with focal NFL defects, OCTs showed significant thinning of the NFL in areas closely corresponding to focal defects visible on clinical examination, to red-free photographs, and to defects on the Humphrey visual fields. Optical coherence tomography enabled the detection of focal defects in the NFL with a sensitivity of 65% and a specificity of 81%. CONCLUSION Analysis of NFL thickness in eyes with focal defects showed good structural and functional correlation with clinical parameters. Optical coherence tomography contributes to the identification of focal defects in the NFL that occur in early stages of glaucoma.

Effect of optic nerve head drusen on nerve fiber layer thickness

OBJECTIVE The purpose of the study was to evaluate the effect of optic nerve head drusen (ONHD) on nerve fiber layer (NFL) thickness by visual field testing, red-free photography of NFL, and optical coherence tomography (OCT). DESIGN The study design was a prospective clinical study. PARTICIPANTS Twenty-three eyes of 15 consecutive patients with ONHD and 27 eyes of 27 age-matched control subjects participated. INTERVENTION Ophthalmologic examination, color and red-free photography, automated Humphrey visual field testing, and OCT were performed. Each of the drusen study eyes were graded on a scale of 0 to III based on the amount of visible ONHD. Grade 0 represented the absence of clinically visible ONHD, and grade III represented an optic nerve head with abundant drusen. MAIN OUTCOME MEASURES Findings from clinical evaluation and color optic nerve head photographs and NFL evaluation by red-free photography, visual fields, and OCT were measured. RESULTS The number of study eyes with visual field defects increased with the higher grade drusen discs, corresponding both with progressively thinner NFL measurements by OCT and NFL loss shown by NFL photography. The NFL evaluation showed NFL thinning by red-free photography in 12 (71%) of 17 eyes with visible drusen (grades I-III discs) and visual field defects in 9 (53%) of 17 eyes in this group. By OCT measurements, the superior and inferior NFLs were significantly thinner in the eyes with visible ONHD compared with those of control eyes in the superior quadrant (P < 0.001) and inferior quadrant (P = 0.004). Compared with grade 0 discs, grades I through III discs showed statistically significant thinning of the NFL superiorly (P < 0.001). No statistical significant thinning of the NFL was seen in grade 0 discs compared with those of control subjects. CONCLUSIONS Optical coherence tomography is able to detect NFL thinning in eyes with ONHD and appears to be a sensitive and early indicator of NFL thinning. Increased numbers of clinically visible ONHD correlated with NFL thinning shown by OCT measurements and both visual field defects and NFL loss seen by red-free photography.

Optical Coherence Tomography Measurement of Nerve Fiber Layer Thickness and the Likelihood of a Visual Field Defect

PURPOSE To determine if optical coherence tomography (OCT) measurements of nerve fiber layer (NFL) thickness can be used to predict the presence of visual field defects (VFD) associated with glaucoma. DESIGN Quota-sampled, cross-sectional study. METHODS Retrospective study of OCT NFL thickness measurements in 276 eyes of 276 subjects. All persons received OCT NFL thickness analysis; 136 eyes underwent frequency-doubling technology (FDT) perimetry; and 140 eyes underwent Swedish interactive threshold algorithm (SITA) perimetry. We defined a parameter called NFL(50), which is the NFL thickness value at which there was a 50% likelihood of a VFD with either SITA or FDT perimetry. We evaluated the use of NFL(50). RESULTS The mean NFL thickness with (n = 68) and without (n = 68) a VFD in the FDT group was 93.2 microm +/- 22.6 and 108.4 microm +/- 14.1, respectively. The mean NFL thickness with (n = 70) and without (n = 70) a VFD in the SITA group was 78.9 microm +/- 24.8 and 103.0 microm +/- 18.0, respectively. The FDT mean NFL(50) value was 98.5 microm. The SITA mean NFL(50) value was 87.0 microm. The area under the receiver operator characteristic (AROC) curve for mean NFL was 0.73, and the positive predictive value (PPV) for FDT mean NFL(50) was 72.2%. For SITA mean NFL, the AROC was 0.79 and the PPV for NFL(50) was 77.2%. CONCLUSION Nerve fiber layer thickness analysis using OCT may be clinically useful in identifying subjects who have visual field loss. However, the PPV suggests that OCT may need higher resolution and better reproducibility to enhance its sensitivity and specificity for population screening.

Comparison of mitomycin C trabeculectomy, glaucoma drainage device implantation, and laser neodymium : YAG cyclophotocoagulation in the management of intractable glaucoma after penetrating keratoplasty

PURPOSE This study aimed to compare the surgical outcomes of mitomycin C trabeculectomy glaucoma drainage device (GDD) surgery and laser neodymium:YAG (Nd:YAG) cyclophotocoagulation (CPC) in the management of intractable glaucoma after penetrating keratoplasty (PKP) in a retrospective study. DESIGN Interventional case series. PARTICIPANTS/METHODS The medical charts of consecutive patients who had pre-existing glaucoma or who developed glaucoma after PKP and underwent a surgical procedure to control the glaucoma at the University Eye Associates of Boston University Medical Center, New England Eye Center, and Massachusetts Eye and Ear Infirmary between January 1991 and July 1995 were reviewed. Follow-up ranged from 6 months to 4 years after the glaucoma procedure. A total of 38 patients were included consisting of 17 patients who underwent mitomycin C, 10 patients who underwent GDD surgery, and 11 patients who had CPC. INTERVENTION Mitomycin C trabeculectomy, GDDs, or Nd:YAG CPC to control glaucoma after PKP was performed, MAIN OUTCOME MEASURES Graft status, postoperative intraocular pressure (IOP), and visual acuity were the main outcome measures. RESULTS There were no differences among the three groups with respect to the follow-up time after the corneal graft operation (P = 0.15) or after the glaucoma operation (P = 0.98). At the final follow-up, the average decrease in the IOP was 17 mmHg (P < 0.001) after mitomycin C, 15 mmHg (P = 0.003) after GDD surgery, and 14.4 mmHg (P = 0.001) after CPC. There were no differences in the proportion of patients who developed postoperative IOP above 20 mmHg (P = 0.50) and in the proportion who developed hypotony (P = 0.10) among the three groups. Two grafts failed after mitomycin C and one failed after CPC. Among the three procedures, there were no differences in the proportion of patients who experienced either an improvement (P = 0.14) or a decrease (P = 0.22) in the visual acuity by more than one line after the glaucoma procedure. One patient each in the GDD group and the CPC group lost light perception after the procedure. The risk of graft failure was almost three times higher for each additional PKP (odds ratio = 2.80, P = 0.02). CONCLUSIONS No differences were found among the three glaucoma procedures with respect to controlling IOP and graft failure. There was a trend for patients treated with CPC to have a higher incidence of graft failure, glaucoma failure, hypotony, and visual loss by more than one line, although this was not statistically significant. The number of PKPs was associated with graft failure, independent of the surgical procedure.

A Prospective Study of Diabetes, Lifestyle Factors, and Glaucoma Among African-American Women

PURPOSE To evaluate the association of self-reported type 2 diabetes, anthropometric factors, alcohol consumption, and cigarette smoking with risk of primary open-angle glaucoma (POAG) in a prospective cohort study of African-American women. METHODS From 1995 through 2007, 32,570 Black Womens Health Study participants aged 21 to 69 years at baseline were followed for incident POAG. Questionnaires were mailed biennially to update exposures and identify incident cases of POAG. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were derived from Cox regression models. RESULTS During 416,171 person-years of follow-up, 366 incident POAG cases were confirmed by physician report. After adjustment for potential confounders, the IRR comparing women with and without type 2 diabetes was 1.58 (95% CI, 1.17-2.13), and the IRR comparing current with never alcohol consumers was 1.35 (95% CI, 1.05-1.73). Among women younger than 50, associations with diabetes and alcohol consumption were stronger, and POAG was significantly associated with body mass index, waist circumference, waist-to-hip ratio, and both long-duration and high-intensity current smoking. CONCLUSIONS These results suggest that type 2 diabetes and current alcohol consumption are independent risk factors for POAG among African-American women, and that in addition to those factors, overall and central adiposity and smoking may be associated with increased risk of early-onset POAG.

Clinical Assessment of Mirror Artifacts in Spectral-Domain Optical Coherence Tomography

PURPOSE. To investigate the characteristics of a spectral-domain optical coherence tomography (SD-OCT) image phenomenon known as the mirror artifact, calculate its prevalence, analyze potential risk factors, measure severity, and correlate it to spherical equivalent and central visual acuity (VA). METHODS. OCT macular cube 512 x 128 scans taken between January 2008 and February 2009 at the New England Eye Center were analyzed for the presence of mirror artifacts. Artifact severity was determined by the degree of segmentation breakdown that it caused on the macular map. A retrospective review was conducted of the medical records of patients with artifacts and of a random control group without artifacts. RESULTS. Of 1592 patients, 9.3% (148 patients, 200 eyes) had scans that contained mirror artifacts. A significantly more myopic spherical equivalent (P < 0.001), worse VA (P < 0.001), longer axial lengths (P = 0.004), and higher proportions of moderate to high myopia (P < 0.001) were found in patients with mirror artifacts than in patients without artifacts. Worse VA was associated with increased artifact severity (P = 0.04). CONCLUSIONS. In all scans analyzed, a high prevalence of mirror artifacts was found. This image artifact was often associated with patients with moderate to high myopia. Improvements in instrumentation may be necessary to resolve this problem in moderately and highly myopic eyes. Operators should be advised to properly position the retina when scanning eyes. In cases in which peripheral abnormalities in topographic measurements of retinal thickness are found, corresponding OCT scans should be examined for the presence of mirror artifacts.

Ocular hypotensive efficacy of bimatoprost when used as a replacement for latanoprost in the treatment of glaucoma and ocular hypertension.

PURPOSE To evaluate the clinical effectiveness of bimatoprost (Lumigan, Allergan, Inc.) when used as a replacement for latanoprost (Xalatan, Pharmacia) in the treatment of glaucoma and ocular hypertension. METHODS This was a community-based, two-month, open-label, multicenter, trial. Patients with glaucoma or ocular hypertension who needed additional IOP lowering or who were intolerant of other glaucoma medications were placed on bimatoprost therapy (alone or in combination with other drugs at the physicians discretion). RESULTS This first report of the data from this study focuses on those patients for whom the physician chose to replace latanoprost therapy with bimatoprost therapy (n = 1283). After 2 months of bimatoprost therapy, the mean decrease in IOP was 3.4 mm Hg and many more patients had achieved low target pressures. The percentage of patients achieving a target pressure of < or =18 mm Hg doubled from 33% to 66% (P <.001). The percentage of patients achieving target pressures of < or =15 mm Hg and < or =14 mm Hg was approximately 3 to 4 times greater at the end of the study than the beginning; increasing from 11% to 36% and from 6% to 26%, respectively (P <.001). A subgroup analysis showed comparable improvements in IOP-control regardless of the previous treatment regimen or whether bimatoprost was used alone or in combination with other medications. The most commonly reported adverse event was conjunctival hyperemia (3.7%; 47/1283). CONCLUSION Bimatoprost therapy is well-tolerated and helps many more patients reach low target pressures when used as a replacement for latanoprost in a variety of treatment regimens.

Glaucoma Filtration Surgery and Antimetabolites

Two studies compared the success of filtration surgery in high-risk eyes using postoperative 5-FU and mitomycin-C, and found that IOPs are lower, and fewer postoperative glaucoma medications are required for control in eyes treated with mitomycin. A similar number of complications occurred in both groups except for a higher incidence of corneal toxicity in the 5-FU treated eyes. Mitomycin-C offers the additional convenience of a single intraoperative application. 5-FU also may be used as an intraoperative application, but no studies have been published regarding its comparable efficacy or safety compared with mitomycin-C. 5-FU has the advantage of being able to use it at any time in the early postoperative course when bleb inflammation arises. 5-FU has known complications, while mitomycin-C, although it appears relatively safe, has been used in fewer patients so far. The advantage of greater surgical success, with lower intraocular pressures, puts antimetabolites into the armamentarium of every surgeon who performs glaucoma procedures.

Macular changes detected by Fourier‐domain optical coherence tomography in patients with hypotony without clinical maculopathy

Purpose:  To investigate macular changes in eyes with postoperative hypotony without clinical maculopathy using high‐resolution Fourier‐domain optical coherence tomography (FD‐OCT).