Effect of cataract and its removal on signal strength and peripapillary retinal nerve fiber layer optical coherence tomography measurements.

PURPOSE: To assess the effect of cataract on optical coherence tomography (OCT), signal strength (SS), and peripapillary retinal nerve fiber layer (RNFL) thickness measurements. METHODS: Peripapillary RNFL thickness measurements were obtained by Stratus OCT scans using the Fast RNFL thickness (3.4) acquisition protocol before and after cataract extraction in 45 patients with cataract, including 23 glaucoma patients. Cataracts were graded according to the Lens Opacities Classification System III. RESULTS: The postoperative RNFL thickness and SS were 9.3% (P=0.001) and 24.1% (P<0.001) higher than before surgery, respectively. There was greater postoperative change in RNFL thickness measurements in patients with lower preoperative RNFL measurements (r=-0.63, P<0.001) and SS (r=-0.59, P<0.001). Eyes with preoperative SS more than 6 had no significant difference between precataract and postcataract surgery RNFL thickness (P=0.14). There was no significant difference in RNFL thickness change between eyes with cataract only (10.9±20.8 µm) and those with cataract and glaucoma (7.0±14.7 µm; P=0.81). CONCLUSIONS: Cataracts may decrease peripapillary RNFL thickness measurements and the SS on OCT scans. Thinning of the peripapillary RNFL suggestive of glaucomatous progression may be the result of artifact from advancing cataract rather than actual structural changes in the peripapillary RNFL. Peripapillary RNFL thickness measurements should be interpreted with caution in glaucomatous eyes with significant cataract, particularly if the SS is attenuated.

Clinical findings and management of conjunctival intraepithelial neoplasia.

BACKGROUND: Conjunctival intraepithelial neoplasia (CIN) is the most common tumor of the ocular surface and is a precursor to invasive squamous cell carcinoma. CIN comprises a spectrum of premalignant epithelial neoplasia that usually begins near the limbus and spreads to the cornea. METHODS: This case report reviews the clinical findings and management of CIN, with a discussion of the histopathology and etiology of this tumor. CONCLUSION: CIN has a variety of clinical presentations, including gelatinous, leukoplakic, or papilliform. Because of their malignant potential, these lesions must be differentiated carefully and treated promptly. Traditional management of CIN is surgical excision with cryotherapy, but other topical treatments are being explored with promising results.

Characteristics of optic nerve head drusen on optical coherence tomography images.

BACKGROUND AND OBJECTIVE: To describe the characteristics of optic nerve head drusen in optical coherence tomography (OCT) images. PATIENTS AND METHODS: Cross-sectional images of the optic nerve were obtained in seven patients with optic nerve head drusen with Stratus and spectral-domain OCT (Carl Zeiss Meditec, Dublin, CA). These were compared to optic disc photographs, autofluorescence, and echography images. For comparison, these tests were performed on four patients with papilledema and three patients with small optic discs. RESULTS: Optic nerve head drusen typically elevated the disc surface and appeared as an optically empty cavity, sometimes with a perceptible reflection from the posterior surface. The disc surface was also elevated in cases of papilledema, but had a strong anterior reflectance behind which there was no visible structure. The surface of the small optic nerves was slightly elevated, but with less anterior reflectance. CONCLUSION: Optic nerves with drusen showed features in these OCT images that were distinct from cases of papilledema or small optic discs.

Evaluation of decision rules for frequency-doubling technology screening tests.

PURPOSE: Frequency-doubling technology (FDT) perimetry has shown promise as a screening test for glaucoma. This study investigates different possible decision rules for FDT screening by applying them to groups of normal and glaucoma subjects. METHODS: Within three centers, 218 subjects (aged 15-88 years; 78 with glaucoma, 140 without ocular disease) were each tested twice with the screening program of the FDT perimeter. The subjects consisted of 140 normal subjects with no evidence of glaucoma or other ocular disease likely to affect the visual field and 78 subjects with a diagnosis of glaucoma and no other ocular disease. Fifteen decision rules were applied to the data to compare their sensitivity and specificity. RESULTS: Estimated specificities of the different decision rules ranged from 78% to 99%, although with this sample size, the confidence intervals for these estimates are quite large. Estimated sensitivities ranged from 40% to 72%. Suggested criteria for distinguishing normal subjects from those with glaucoma seem to be either a cluster of two or more adjacent locations abnormal at the p < 2% level with at least one location confirmed or a single location very abnormal (p < 1%) and confirmed. CONCLUSIONS: Specificity was clearly improved by confirming an apparently abnormal test result by repeating the screening test outweighing the resultant small loss in sensitivity. These findings provide useful information for making an informed choice of decision rules for FDT screening results.

A cost analysis of the prostaglandin analogs.

BACKGROUND: The efficacy, ease of use, and favorable side effect profile has increased the popularity of the prostaglandin analogs for topical treatment of a variety of glaucoma types. We undertook a cost analysis study of all the prostaglandin analogs. METHODS: Mean number of drops per bottle, mean drop volume, total bottle volume, percent overfill per bottle, mean national bottle cost, daily cost of therapy, and yearly cost of therapy were calculated for all four of the prostaglandin analogs. RESULTS: Yearly cost of monocular therapy was $230.68 for latanoprost, $219.37 for travoprost, $211.34 for bimatoprost, and $178.85 for unoprostone. Unoprostone was by far the least expensive of the prostaglandin analogs tested. Bimatoprost, latanoprost, and travoprost were essentially the same price, varying in yearly cost to the patient by less than twenty dollars. Bimatoprost had the most expensive bottle price, unoprostone the least expensive. Bimatoprost also had the largest percentage of overfill from labeled volume. Unoprostone had the most monocular treatment days per bottle. CONCLUSION: Cost, in addition to efficacy and side affect profile, should be considered when determining which prostaglandin analog to prescribe to glaucoma patients.