Retinal nerve fiber layer measurements in myopia using optical coherence tomography

@#<p style="text-align: justify;"><strong>OBJECTIVE:</strong> To evaluate the relationship between retinal nerve fiber layer (RNFL) thickness measured by optical coherence tomography (OCT) and the degree of myopia.<br /><strong>METHODS:</strong> A total of 28 eyes of 14 healthy subjects with myopia, 9 eyes with low myopia (spherical equivalent [SE] between -0.75 D and -3.00 D) and 19 eyes with moderate to high myopia (SE >-3.0 D), were included. Total average<br />and mean quadrant RNFL thicknesses were measured by Stratus OCT. Associations between RNFL measurements and spherical equivalent refraction were evaluated by linear regression analysis.<br /><strong>RESULTS:</strong> Twenty two out of 28 eyes were classified as below normal limits with reference to the normative database of the RNFL thickness. There was a significant correlation between refraction and average RNFL thickness (p=0.04), indicating that for every decrease of 1.00 D in refraction (more myopic), there was a 2.86 µm decrease in the average RNFL thickness. The most frequently abnormal sector was at the nasal quadrant, where 78% of myopic eyes were below normal limits. A significant correlation was seen between refraction and nasal RNFL thickness (p=0.02), showing a decrease of 3.37 µm in the nasal RNFL thickness for every 1.00 D decrease. There was also a significant correlation between refraction and inferior RNFL thickness (p=0.007). For every decrease of 1.00 D in refraction, there was a decrease of 6.27 µm in the inferior RNFL thickness. There were no significant correlations between the refraction and the superior and temporal RNFL thickness (p = 0.12 and 0.64, respectively).<br /><strong>CONCLUSION:</strong> There was a decrease in the average RNFL thickness as the refractive error became more myopic, suggesting the need for the Stratus OCT RNFL normative database to have corrective factors for refractive error among myopic patients. Although both the nasal and inferior quadrants positively correlated with myopia, majority of the nasal quadrant showed below normal thickness based on the Stratus OCT normative database. A careful interpretation of RNFL measurements, especially the nasal quadrant, should be done among myopic subjects to avoid mislabeling them as glaucoma suspects.</p>

Correlation of optic-disc area and refractive error

Objective@#This study measured the optic-disc area using optical coherence tomography (OCT) and correlated it with the type of refractive error.@*Methods@#A cross-sectional study was conducted involving 73 healthy Filipinos aged 20 to 60 years. All underwent a full ophthalmologic examination including visual acuity, automated refraction, Goldmann applanation tonometry, and dilatedfundus examination. Fast optic-nerve-head imaging was performed with 6 radial linear scans centered on the optic-nerve head. Data were tabulated and the association between optic-disc measurements and refractive error was analyzed using analysis of variance and linear regression.@*Results@#A total of 142 eyes of 73 patients were included, of which 39 (27.5%) were classified as emmetropia or hyperopia, 47 (33%) as low myopia, 37 (26.2%) as moderate myopia, and 19 (13.4%) as high myopia. The mean refractive error was –9.2 ± 2.98D for those with high myopia, –4.7 ± 0.74D for moderate myopia, –1.7 ± 0.78D for low myopia, and 1.1 ± 2.55D for emmetropia and hyperopia. The mean optic-disc area for all groups was 2.70 ± 0.59 mm2 (range, 1.6 to 4.7 mm2 ); the mean optic-disc area was similar for high myopia (2.7 ± 0.57 mm2 ) and low myopia (2.7 ± 0.52 mm2 ). There was no significant difference in the optic-disc area of the different types of refractive errors (p = 0.30).@*Conclusion@#This study showed that the optic-disc area is statistically independent of the refractive error.

Steroid-induced cataract and glaucoma in pediatric patients with nephrotic syndrome

Objective@#This study investigated ocular complications, such as cataract and glaucoma, arising from prolonged corticosteroid therapy in children.@*Methods@#A cross-sectional study involving pediatric patients with nephrotic syndrome was conducted in a tertiary hospital. Comprehensive ophthalmic assessments including best-corrected visual acuity (BCVA), intraocular pressure (IOP), slitlamp and fundus examination were performed. Standard automated perimetry (SAP) was also performed on patients suspected of having glaucoma. Information on renal histological diagnosis and treatment regimen in each patient was noted. Data were analyzed statistically.@*Results@#A total of 22 patients were evaluated. The median age at the time of examination was 9.5 years (range, 2 to 17 years). The mean age of onset was 6.9 ± 4.3 years. Twelve of the 22 patients had relapses with a mean of 1.86. The mean duration of steroid use was 28 ± 28.9 months. Eleven patients (50%) were given combined therapy (prednisone with either cyclosporine or cyclophosphamide) and 11 were given oral prednisone alone. The mean dose of steroid at the time of examination was 27 ± 26.2 mg/m2 /day. Among the 22 patients, 3 (13.6%) developed posterior subcapsular cataracts. One patient developed steroidinduced glaucoma with a scotoma encroaching the central 10o visual field. There was a significant association between the duration of corticosteroid treatment and cataract formation (p = 0.04), but no significant association between the duration of therapy and development of glaucoma (p = 0.45).@*Conclusions@#Cataract formation was a more common complication of prolonged oral corticosteroid therapy with a prevalence rate of 13.6%. Pediatric patients with a longer duration of steroid therapy are at greater risk of cataract formation. Hence, pediatricians are advised to refer these patients to ophthalmologists for proper evaluation.