Low vision and the risk of dementia: a nationwide population-based cohort study.

Recent studies suggested that an association exists between vision loss and cognitive impairment, although it is still vague whether there are causal relationships or direct association between low vision and dementia. We were to investigate the association between low vision and dementia in the Korean population using the National Health Insurance Service (NHIS) database. We analyzed the data of 6,029,657 subjects aged ≥40 years, drawn from Korea National Health Insurance Service. The hazard ratio (HRs) and 95% confidence interval (CIs) of dementia, Alzheimer's disease (AD), and Vascular dementia (VD) were estimated using multivariable Cox proportional hazards regression models. Statistical analysis showed that subjects with more severe visual impairments have a higher risk of dementia, AD, and VD after adjusting for compounding variables. The HRs of dementia increased significantly as visual acuity worsened (HRs 1.444 [95% CIs 1.415-1.473] for visual acuity (VA) < 1.0, 1.734 [1.693-1.777] for VA < 0.3, 1.727 [1.686-1.770] for VA < 0.1 and 1.991[1.902-2.085] for visual loss). Baseline visual loss and visual impairment were positively associated with the risk of dementia, AD, and VD. From the results of this nationwide population-based cohort study, we suggest that there is a significant increase in the incidence of dementia in subjects with low vision.

Comparison of prelaminar thickness between primary open angle glaucoma and normal tension glaucoma patients.

MAIN OBJECTIVE: The thinning of prelaminar tissue and prelamina cupping is known to occur by ischemia, as we see in anterior ischemic optic neuropathy. Since normal tension glaucoma (NTG) is thought to be more related to vascular factor than in primary open-angle glaucoma (POAG), we hypothesized that prelamina thinning may occur prominently in NTG patients. This study investigated the difference in prelaminar tissue thickness between patients with POAG and NTG and verified the factors related to prelaminar thinning. METHODS: Complete ophthalmic examination including standard automatic perimetry was performed in all patients. The prelaminar tissue thickness was measured in all patients by performing enhanced depth imaging with a Heidelberg Spectralis Optical Coherence Tomography. The retinal nerve fiber layer and optic nerve head parameters were obtained using the Heidelberg Retina Tomography II and Cirrus Optical Coherence Tomography. Various ocular factors and their relationships with prelaminar thickness were analyzed. RESULTS: The mean prelaminar tissue thickness was significantly thinner in patients with POAG than in those with NTG. The difference in the prelaminar thickness between patients with POAG and those with NTG was greater in the early field defect group than in the moderate and severe field groups. In multivariate analysis, the mean prelaminar thickness was related to the intraocular pressure, mean deviation, cup-disc ratio, and cup volume. CONCLUSIONS: The prelaminar tissue was thinner in patients with POAG than in patients with NTG, and intraocular pressure had a strong influence on the prelaminar thickness in both POAG and NTG. This may indicate that mechanical compression is the main pathogenic factor in both POAG and NTG.

Interocular retinal nerve fiber layer thickness symmetry value in normal young adults.

PURPOSE: The aim of this study was to determine the normal range of interocular peripapillary retinal nerve fiber layer (RNFL) thickness symmetry value in young adults. Factors affecting interocular RNFL thickness symmetry were also investigated. MATERIALS AND METHODS: Both eyes of 241 ophthalmologically and neurologically normal subjects were scanned using optical coherence tomography (200×200 optic disc cube protocol). The effect of ocular cyclotorsion on interocular RNFL thickness symmetry was determined and mathematically accounted for. Symmetry value between the right and left RNFL thickness values was calculated. Linear regression analyses were used to identify correlations between the corrected interocular symmetry value and interocular differences in refractive error, axial length, superior and inferior temporal retinal artery and vein location, and optical coherence tomography signal strength. RESULTS: The mean interocular RNFL thickness symmetry value before and after correction of ocular cyclotorsion was 0.8791±0.0665 and 0.9044±0.0571 (P<0.001), respectively. Interocular differences in axial length, inferior temporal retinal arcade location, and refractive error were weakly and negatively correlated with the ocular cyclotorsion-corrected symmetry value (P<0.05). Anatomic differences between the eyes in the location of the superior temporal retinal artery and vein were strongly correlated with the corrected symmetry value (P<0.01, R=0.208). CONCLUSIONS: On the basis of the data obtained here from normal individuals, a corrected symmetry value of <0.77 might indicate the presence of pathologic conditions affecting the RNFL. Interocular RNFL thickness symmetry was influenced more heavily by interocular superotemporal vessel location than by anisometropia.

A case of concomitant keratoconus and granular corneal dystrophy type II.

PURPOSE: We report a Korean case of concomitant keratoconus and granular corneal dystrophy type II. METHODS: Case report. RESULTS: A 29-year-old man visited our clinic for a routine ocular check-up. Slit-lamp examination revealed a few well-circumscribed, greyish-white, discrete granular opacities in the central corneal stromae of both eyes. Direct sequencing of exon 4 of the BIGH3 gene revealed a heterozygous transversion from G to A in the second-nucleotide position of codon 124. In addition, a Fleischer ring and Vogt's striae were evident in the cornea. The corneal topography was suggestive of keratoconus. CONCLUSION: Granular corneal dystrophy type II can co-exist with keratoconus and should be included in the differential diagnosis.

Unilateral lateral rectus advancement with medial rectus recession vs bilateral medial rectus recession for consecutive esotropia.

BACKGROUND: To compare unilateral lateral rectus (LR) advancement with medial rectus (MR) recession with bilateral MR recession for patients with consecutive esotropia (ET). METHODS: Twenty-nine patients who developed consecutive ET of 30-35 PD following bilateral LR recession for intermittent exotropia were retrospectively reviewed. LR advancement into the original insertion site with 4.5 mm (30 PD ET) and 5.0 mm (35 PD ET) MR recession in the chiefly deviating eye was performed in 14 patients (A&R group). For 15 patients (BMR group), 4.5 and 5.0 mm bilateral MR recession was performed for 30 and 35 PD esodeviation respectively. As the primary outcome measure, postoperative ocular alignment between 5 PD of esophoria and 10 PD exophoria was considered a success. RESULTS: At 12 months postoperatively, successful surgical outcome was noticed in 12 patients (85.7%) in the A&R group and 11 patients (73.3%) in the BMR group. There was no statistically significant difference of final success rate between the A&R group and BMR group (p = 0.411). At 12 months after surgery for consecutive ET, seven (50%) and eight patients (53.3%) acquired binocular fine stereopsis ≤100 s of arc in the A&R and BMR groups respectively CONCLUSIONS: Advancement of the previously recessed LR with recession of the MR in the chiefly deviating eye has a high success rate comparable to that of bilateral MR recession, with the advantage of preserving one MR muscle for potential future intervention.