Author: Ophthalmology

Oral Docosahexaenoic Acid in the Prevention of Exudative Age-Related Macular Degeneration: The Nutritional AMD Treatment 2 Study

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Objective: To evaluate the efficacy of docosahexaenoic acid (DHA)–enriched oral supplementation in preventing exudative age-related macular degeneration (AMD).Design: The Nutritional AMD Treatment 2 study was a randomized, placebo-controlled, double-blind, parallel, comparative study.Participants: Two hundred sixty-three patients 55 years of age or older and younger than 85 years with early lesions of age-related maculopathy and visual acuity better than 0.4 logarithm of minimum angle of resolution units in the study eye and neovascular AMD in the fellow eye.Methods: Patients were assigned randomly to receive either 840 mg/day DHA and 270 mg/day eicosapentaenoic acid (EPA) from fish oil capsules or the placebo (olive oil capsules) for 3 years.Main Outcome Measures: The primary outcome measure was time to occurrence of choroidal neovascularization (CNV) in the study eye. Secondary outcome measures in the study eye were: incidence of CNV developing in patients, changes in visual acuity, occurrence and progression of drusen, and changes in EPA plus DHA level in red blood cell membrane (RBCM).Results: Time to occurrence and incidence of CNV in the study eye were not significantly different between the DHA group (19.5±10.9 months and 28.4%, respectively) and the placebo group (18.7±10.6 months and 25.6%, respectively). In the DHA group, EPA plus DHA levels increased significantly in RBCM (+70%; P<0.001), suggesting that DHA easily penetrated cells, but this occurred unexpectedly also in the placebo group (+9%; P = 0.007). In the DHA-allocated group, patients steadily achieving the highest tertile of EPA plus DHA levels in RBCM had significantly lower risk (−68%; P = 0.047; hazard ratio, 0.32; 95% confidence interval, 0.10–0.99) of CNV developing over 3 years. No marked changes from baseline in best-corrected visual acuity, drusen progression, or geographic atrophy in the study eye were observed throughout the study in either group.Conclusions: In patients with unilateral exudative AMD, 3 years of oral DHA-enriched supplementation had the same effect on CNV incidence in the second eye as did the placebo. However, RBCM fatty acid measurements revealed that CNV incidence was significantly reduced in DHA-supplemented patients showing a steadily high EPA plus DHA index over 3 years.Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references.

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A Quantitative Method for Assessing the Degree of Axial Proptosis in Relation to Orbital Tissue Involvement in Graves’ Orbitopathy – Corrected Proof

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Purpose:
To define a method of quantifying axial proptosis in patients with Graves’ orbitopathy (GO) and to validate a score that correlates with the orbital involvement and helps determine the degree of proptosis correction for elective orbital decompression.

Design:
Retrospective, case series.

Participants:
The study included 50 patients (group A) and 29 control subjects who underwent orbital computed tomography (CT). The method was then validated in another group of 21 patients with GO (group B).

Methods:
The orbital area (OA) was measured manually on the central axial section of the CT scan at a level where the lens is visualized. The OA intersects the projection of the globe and delimitates the chord of an arch (globe chord [OC]). The area of the circular sector under the chord (CA) represents the portion of the globe within the orbit.

Main Outcome Measures:
A CA-to-OA ratio was calculated to reduce the error due to variability of the measurements and to perform correlations with some of the clinical parameters of GO.

Results:
Measurement error was low (<2%). We did not observe significant differences in the mean OA of patients with GO (783.6±12.1 mm2) and controls (758.5±20.4 mm2; P = not significant). The OC value in patients with GO was 130.2±11.5 mm2, significantly lower than in controls (281.8±9.7 mm2; P<0.0001). The CA-to-OA ratio also was lower in patients with GO than in controls (0.16±0.01 vs. 0.38±0.01; P<0.0001). A significant correlation was found in patients with GO between the CA-to-OA ratio and proptosis (P<0.001), lid fissure (P = 0.004), and intraocular pressure (P<0.001). In group B, the CA-to-OA ratio was 0.18±0.02, significantly different from that of controls (P<0.0001) and inversely correlated with proptosis (P<0.0001) and lid fissure (P<0.045).

Conclusions:
By measuring the CA-to-OA ratio, we were able to quantify the degree of axial proptosis in patients with GO. The significant correlation of CA/OA with some orbital parameters confirms that this parameter also may be used as a measure of orbital involvement in GO.

Financial Disclosure(s):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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Effect of Day Length on Eye Growth, Myopia Progression, and Change of Corneal Power in Myopic Children

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Objective:
Because of the northern location of Denmark, the length of the day over the year varies from 7 to 17.5 hours. Experimental and clinical results suggest that the development of myopia may be related to ambient light exposure. The purpose of current study was to investigate whether axial eye growth, myopia progression, or corneal power change in Danish myopic children varies with the length of the day.

Design:
Cross-sectional study.

Participants:
Two hundred thirty-five children 8 to 14 years of age found to have myopia during screening for a clinical trial (ClinicalTrial.gov identifier, NCT00263471; accessed December 6, 2005). All children found to have any value of spherical equivalent that was myopic (<0 diopters [D]) at the first of 2 visits were included.

Methods:
Cycloplegic refraction was measured using an autorefractor, axial eye length, and corneal power using an automatic combined noncontact partial coherence interferometer and keratometer. The accumulated number of daylight hours during the measurement period was calculated for each participant using an astronomical table.

Main Outcome Measures:
Change over 6 months in axial length, refraction, and corneal power.

Results:
Accumulated hours of daylight ranged from 1660 to 2804 hours. Significant correlations were found between hours of daylight and eye elongation (P = 0.00), myopia progression (P = 0.01), and corneal power change (P = 0.00). In children with an average of 2782±19 hours of daylight, axial eye growth was 0.12±0.09 mm, myopia progression was 0.26±0.27 D, and corneal power change was 0.05±0.10 D per 6 months, whereas in children with an average of 1681±24 hours of daylight, axial eye growth was 0.19±0.10 mm, myopia progression was 0.32±0.27 D, and corneal power change was −0.04±0.08 D per 6 months.

Conclusions:
Eye elongation and myopia progression seem to decrease in periods with longer days and to increase in periods with shorter days. Children should be encouraged to spend more time outside during daytime to prevent myopia.

Financial Disclosure(s):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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Treatment Outcomes in Malignant Glaucoma

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Purpose:
To report treatment outcomes in malignant glaucoma.

Design:
Retrospective case series.

Participants:
Twenty-eight eyes of 26 patients who were treated for malignant glaucoma between 1991 and 2009.

Methods:
Malignant glaucoma was diagnosed based on the presence of a shallow or flat central and peripheral anterior chamber in the presence of patent iridotomy, with intraocular pressure (IOP) of 22 mmHg or more after any intraocular surgery. The treatment algorithm included antiglaucoma medications and cycloplegics as first-line methods; the second-line therapy in pseudophakic eyes was laser hyaloidotomy, followed by vitrectomy-hyaloidotomy-iridectomy (VHI) or transscleral cyclophotocoagulation (TSCPC).

Main Outcome Measures:
Resolution was defined as deepening of the central anterior chamber and IOP of 21 mmHg or less (on 2 successive follow-ups at least 1 week apart) with or without topical antiglaucoma medications in the absence of systemic antiglaucoma medications.

Results:
At the diagnosis of malignant glaucoma, 5 eyes were phakic and 23 were pseudophakic. The preceding surgeries were trabeculectomy (11 eyes), cataract surgery (10 eyes), and combined cataract and glaucoma surgery (7 eyes). Mean IOP decreased from 34±8.3 mmHg at presentation to 14.3±5.2 mmHg at the last visit (P<0.001). Resolution of malignant glaucoma was seen in 27 eyes (27/28; 96%), 17 eyes resolved with 1 intervention, and 10 eyes required repeat procedures. Of the 27 eyes whose disease resolved, this result was achieved in 4 eyes with medical treatment, in 7 pseudophakic eyes with laser hyaloidotomy, in 4 eyes with VHI, and in 12 eyes with TSCPC. The median duration of follow-up was 192 days (interquartile range, 35–425 days). There was no difference in the visual acuity at presentation and at the final visit in 14 eyes. Eight eyes gained 2 lines or more and 6 eyes lost 2 lines or more of visual acuity.

Conclusions:
Malignant glaucoma can be managed successfully by appropriate and timely interventions. Medical treatment was beneficial in phakic eyes, laser hyaloidotomy was beneficial in pseudophakic eyes, and vitrectomy and TSCPC were beneficial in refractory cases. A stepladder approach to treatment was successful (96%) in this series.

Financial Disclosure(s):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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Fuchs’ Endothelial Corneal Dystrophy: Subjective Grading versus Objective Grading Based on the Central-to-Peripheral Thickness Ratio

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Purpose:
To assess interobserver agreement between 2 corneal specialists grading Fuchs’ dystrophy clinically and to determine if the corneal central-to-peripheral thickness ratio (CPTR) may be an alternative and objective metric of disease severity.

Design:
Cross-sectional study.

Participants:
Forty-five eyes (26 subjects) with mild and moderate Fuchs’ dystrophy, 73 eyes (60 subjects) with advanced Fuchs’ dystrophy, and 267 eyes (142 subjects) with normal corneas.

Methods:
Corneas with Fuchs’ dystrophy were graded by 2 corneal specialists based on the confluence and area of guttae and the presence or absence of edema. Central corneal thickness (CCT) and peripheral corneal thickness at 4 mm from the center (PCT4) were measured by using scanning-slit pachymetry. The value of CPTR4 was the quotient of CCT and PCT4.

Main Outcome Measures:
Interobserver agreement for clinical grade and CPTR4.

Results:
Interobserver agreement for clinical grading of Fuchs’ dystrophy was moderate (κ = 0.32; 95% confidence interval, 0.19–0.45). In normal corneas, CCT was not correlated with age (r = −0.10; P = 0.28; n = 267), PCT4 decreased with age (r = −0.33; P<0.001; n = 254), and CPTR4 increased with age (r = 0.59; P<0.001; n = 254). Central corneal thickness was higher in Fuchs’ dystrophy (652±61 μm; n = 118) than in normal corneas (559±31 μm; n = 267; P<0.001). Also, PCT4 was higher in Fuchs’ dystrophy (650±51 μm; n = 107) than in normal corneas (643±43 μm; n = 254; P<0.001 after adjusting thickness for age). Furthermore, CPTR4 was higher in advanced Fuchs’ dystrophy (1.03±0.07; n = 65) than in mild and moderate Fuchs’ dystrophy (0.95±0.07; n = 42; age-adjusted P<0.001), which in turn was higher than in normal corneas (0.87±0.05; n = 254; age-adjusted P<0.001). Finally, CPTR4 was highly correlated with clinical grade of Fuchs’ dystrophy (r = 0.77; P<0.001; n = 361), was repeatable (median coefficient of variation, 1.3%), and provided excellent discrimination between Fuchs’ dystrophy and normal corneas (area under the receiver operator characteristic curve, 0.93).

Conclusions:
Agreement between corneal specialists for the subjective and morphologic clinical grading of Fuchs’ dystrophy is only moderate. The corneal CPTR is an objective, repeatable, and possibly functional, metric of severity of Fuchs’ dystrophy that warrants further investigation to determine its role in monitoring disease progression and predicting the need for keratoplasty.

Financial Disclosure(s):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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