Trends in the Prevalence of Blindness and Correlation With Health Status in Korean Adults: A 10-Year Nationwide Population-Based Study

Background@#Contemporary data on vision impairment form an important basis for public health policies. However, most data on the clinical epidemiology of blindness are limited by small sample sizes and focused not on systemic conditions but ophthalmic diseases only. In this study, we examined the ten-year trends of blindness prevalence and its correlation with systemic health status in Korean adults. @*Methods@#This study investigated 10,000,000 participants randomly extracted from the entire Korean population (aged ≥ 20 years) who underwent a National Health Insurance Service health checkup between 2009 and 2018. Participants with blindness, defined as visual acuity in the better-seeing eye of ≤ 20/200, were identified. The prevalence of blindness was assessed, and the systemic health status was compared between participants with blindness and without blindness. @*Results@#The mean prevalence of blindness was 0.473% (47,115 blindness cases) and tended to decrease over ten years (0.586% in 2009 and 0.348% in 2018; P 1.5 mg/dL), and bilateral hearing loss. In addition, except for those aged 30–39 and 40–49 years, high fasting glucose (≥ 126 mg/dL) and low hemoglobin (male: < 12 g/dL, female: < 10 g/dL) were significantly correlated with prevalent blindness. @*Conclusion@#Our ten-year Korean nationwide population-based study suggested a gradual decrease in the prevalence of blindness and its association with specific systemic health status. These conditions might be the cause or consequence of blindness and can be used as a reference for the prevention and/or rehabilitation of blindness to establish public health policies.

Retinal Nerve Fiber Layer-to-Disc Ratio Distinguishing Glaucoma from Nonarteritic Anterior Ischemic Optic Neuropathy

Purpose@#To evaluate the diagnostic value of retinal nerve fiber layer-to-disc ratio (RDR) compared to established parameters including retinal nerve fiber layer thickness (RNFLT), Bruch membrane opening-minimum rim width (BMO-MRW), and Bruch membrane opening-minimum rim area (BMO-MRA) for differentiating between open angle glaucoma (OAG) and nonarteritic anterior ischemic optic neuropathy (NAION). @*Methods@#This retrospective study included 23 optic disc size-matched normal control eyes and 23 OAG and NAION eyes matched according to global RNFLT. The RDR, RNFLT, BMO-MRW, and BMO-MRA were analyzed; the diagnostic capabilities of these parameters were compared using the area under the receiver operating characteristic curve (AUC). @*Results@#The global BMO-MRW and total BMO-MRA were lower in the OAG group than in the other two groups (all p < 0.001). RDR was greatest in the OAG group, followed by the healthy and NAION groups (p < 0.001). Between the OAG and NAION groups, the AUCs for temporal inferior BMO-MRW, total BMO-MRA, and RDR were 0.987, 0.996, and 1.000, respectively; these were greater than the temporal inferior RNFLT (0.811; p = 0.005, p = 0.006, and p = 0.006, respectively). @*Conclusions@#RDR could be one of the useful parameters for differential diagnosis in OAG and NAION.

Applicability of ISNT Rule Using Bruch's Membrane Opening-based Optic Nerve Head Parameters

Purpose@#To evaluate the applicability of the ISNT rule (neuroretinal rim thickness order: inferior > superior > nasal > temporal)when using Bruch's membrane opening-based optic nerve head parameters to discriminate between normal and glaucomatouseyes. @*Methods@#The medical records of 41 normal eyes and 62 open-angle glaucoma eyes were reviewed retrospectively. We analyzedthe neuroretinal rim thickness values corresponding to the superior, inferior, nasal, and temporal sides of the optic disc asmeasured using color stereo optic-disc photographs, Bruch’s membrane opening-minimum rim width (BMO-MRW), theBMO-MRW average, and Bruch’s membrane opening-minimum rim area (BMO-MRA). The sensitivity and specificity of the ISNTrule in differentiating normal and glaucomatous eyes were compared across the four methods. @*Results@#In normal and glaucomatous eyes, measuring neuroretinal rim thickness in color stereo optic-disc photographs producedlarger values for the superior, inferior, nasal, and temporal sides compared to measurements using BMO-MRW and theBMO-MRW average (p< 0.001). With respect to ISNT rule compliance using the four methods, the sensitivities of theBMO-MRW average and BMO-MRA methods were significantly higher than that when disc photographs were used (82.3% vs.98.4%, p< 0.05; and 82.3% vs. 95.2%, p< 0.05, respectively). Specificity did not differ significantly among the four methods. @*Conclusion@#BMO-based optic nerve head parameters exhibited higher diagnostic power for differentiating between normal andglaucomatous eyes based on the ISNT rule, compared with the classic method of using disc photographs.

Location of Retinal Nerve Fiber Layer Defects in Open-angle Glaucoma and Associated Factors

PURPOSE: To investigate the location of retinal nerve fiber layer defects (RNFLDs) in open-angle glaucoma and the differences in systemic and ocular factors between superotemporal and inferotemporal RNFLDs. METHODS: We performed a retrospective review of the 2008 to 2012 data from the Korea National Health and Nutrition Examination Survey. Subjects aged ≥19 years with an evaluable fundus photograph of at least one eye were enrolled, and open-angle glaucoma was diagnosed according to modified International Society of Geographical and Epidemiological Ophthalmology criteria. In subjects with open-angle glaucoma, locations of RNFLDs were evaluated, and systemic and ocular factors were compared between the bilateral superotemporal RNFLD group and bilateral inferotemporal RNFLD group. RESULTS: A total of 534 subjects had open-angle glaucoma with RNFLDs. The unilateral inferotemporal region (25.8%) was the most common location for RNFLDs, followed by the unilateral superotemporal region (24.4%). Multivariate analysis revealed that hypertension was more significantly associated (p = 0.048) with the bilateral superotemporal RNFLD group than with the bilateral inferotemporal RNFLD group. CONCLUSIONS: Superotemporal RNFLDs are more related to hypertension than are inferotemporal RNFLDs.

Long-Term Changes in Visual Acuity and Foveal Thickness after Vitrectomy for Idiopathic Epiretinal Membrane

PURPOSE: To evaluate the clinical outcomes of visual acuity and foveal thickness after vitrectomy for an idiopathic epiretinal membrane (ERM). METHODS: We retrospectively reviewed the records of 62 patients (62 eyes) with ERM who had been treated with vitrectomy between 2004 and 2009. Visual acuity and central macular thickness from optical coherence tomography imaging were obtained preoperatively and at every postoperative follow-up visit. RESULTS: Mean preoperative visual acuity and central macular thickness were 0.495 +/- 0.292 log MAR and 414.645 +/- 95.528 microm, respectively. Mean visual acuity and central macular thickness 1 month after surgery were 0.389 +/- 0.373 log MAR and 341.484 +/- 73.676 microm, respectively. Visual acuity improved within 9 months and central macular thickness significantly decreased 12 months after surgery. Most of the changes in visual acuity and central macular thickness took place during the first 3 months. The only parameter which was significantly correlated with final visual acuity was preoperative visual acuity (0.635) (p < 0.001). CONCLUSIONS: Visual acuity and central macular thickness improved 12 months months after vitrectomy in patients with idiopathic ERM. Preoperative visual acuity had a significant correlation with final visual acuity.

Consecutive Esotropia after Lateral Rectus Muscle Recession for Intermittent Exotropia

PURPOSE: To evaluate the progress and outcome of consecutive esotropia after surgery for intermittent exotropia. METHODS: The authors investigated the risk factors, changes in the angle of esodeviation and treatment outcome in consecutive esotropia after lateral rectus muscle recession for intermittent exotropia in 196 patients. RESULTS: Consecutive esotropia occurred in 25 patients (12.8%). The patients underwent more frequent combined muscle surgeries on vertical and oblique muscles (p = 0.001) and had a greater amount of immediate postoperative overcorrection than subjects without consecutive esotropia. There was no significant difference with the incidence of overcorrection greater than 17 PD between the 2 groups with and without consecutive esotropia. There was no difference with the immediate postoperative overcorrection between the 6 cases that required surgery for their consecutive esotropia and the cases that recovered from their consecutive esotropia with conservative treatment. The former showed increasing esodeviation and maximum angle at average postoperative month 29.5. In the latter, esodeviation tended to decrease and showed maximum angle at average postoperative month 4.3. Finally, esotropia disappeared and good stereoacuity was obtained in both cases. CONCLUSIONS: Although subjects with consecutive esotropia had a greater immediate postoperative overcorrection than subjects without consecutive esotropia, the progress and outcome of consecutive esotropia following the initial overcorrection were not predictable. Consecutive esotropia after surgery for intermittent exotropia showed good overall outcome and well-preserved stereoacuity after treatment.