FQ-UWF: Unpaired Generative Image Enhancement for Fundus Quality Ultra-Widefield Retinal Images.

Ultra-widefield (UWF) retinal imaging stands as a pivotal modality for detecting major eye diseases such as diabetic retinopathy and retinal detachment. However, UWF exhibits a well-documented limitation in terms of low resolution and artifacts in the macular area, thereby constraining its clinical diagnostic accuracy, particularly for macular diseases like age-related macular degeneration. Conventional supervised super-resolution techniques aim to address this limitation by enhancing the resolution of the macular region through the utilization of meticulously paired and aligned fundus image ground truths. However, obtaining such refined paired ground truths is a formidable challenge. To tackle this issue, we propose an unpaired, degradation-aware, super-resolution technique for enhancing UWF retinal images. Our approach leverages recent advancements in deep learning: specifically, by employing generative adversarial networks and attention mechanisms. Notably, our method excels at enhancing and super-resolving UWF images without relying on paired, clean ground truths. Through extensive experimentation and evaluation, we demonstrate that our approach not only produces visually pleasing results but also establishes state-of-the-art performance in enhancing and super-resolving UWF retinal images. We anticipate that our method will contribute to improving the accuracy of clinical assessments and treatments, ultimately leading to better patient outcomes.

Artificial Intelligence Applications in Diabetic Retinopathy: What We Have Now and What to Expect in the Future.

Diabetic retinopathy (DR) is a major complication of diabetes mellitus and is a leading cause of vision loss globally. A prompt and accurate diagnosis is crucial for ensuring favorable visual outcomes, highlighting the need for increased access to medical care. The recent remarkable advancements in artificial intelligence (AI) have raised high expectations for its role in disease diagnosis and prognosis prediction across various medical fields. In addition to achieving high precision comparable to that of ophthalmologists, AI-based diagnosis of DR has the potential to improve medical accessibility, especially through telemedicine. In this review paper, we aim to examine the current role of AI in the diagnosis of DR and explore future directions.

Macular lesions associated with age-related macular degeneration in pachydrusen eyes.

BACKGROUND: To investigate the prevalence of macular lesions associated with age-related macular degeneration (AMD) in eyes with pachydrusen. METHODS: Clinical records and multimodal imaging data of patients over 50 years old with drusen or drusenoid deposits were retrospectively assessed, and eyes with pachydrusen were included in this study. The presence of AMD features, including drusen or drusenoid deposits, macular pigmentary abnormalities, geographic atrophy (GA), and macular neovascularization (MNV), were evaluated. RESULTS: Out of 967 eyes of 494 patients with drusen or drusenoid deposits, 330 eyes of 183 patients had pachydrusen (34.1%). The mean age was 66.1 ± 9.3 years, and the subfoveal choroidal thickness (SFCT) was 292.7 ± 100.1 µm. The mean number of pachydrusen per eye was 2.22 ± 1.73. The majority of eyes with pachydrusen had no other drusen or drusenoid deposits (95.2%). Only 16 eyes (4.8%) had other deposits, including soft drusen (10 eyes, 3.0%), cuticular drusen (3 eyes, 0.9%), and reticular pseudodrusen (RPD; 3 eyes, 0.9%). Macular pigmentary abnormalities accompanied pachydrusen in 68 eyes (27.4%). None of the eyes had GA, and 82 eyes (24.8%) had MNV. The majority of MNV was polypoidal choroidal vasculopathy (PCV; 65 eyes, 19.7%), followed by type 1 (10 eyes, 3.0%), type 2 (5 eyes, 1.5%), and type 3 MNV (2 eyes, 0.6%). CONCLUSIONS: Eyes with pachydrusen in Korean population have several characteristic AMD lesions in low frequencies. These findings indicate that pachydrusen might have diagnostic and prognostic values that are different from those of other drusen or drusenoid deposits.

Association Between Three Atopic Triad and Retinal Vein Occlusion Risk: A Nationwide Population-Based Study.

PURPOSE: To evaluate the association between three allergic diseases (allergic dermatitis, allergic rhinitis, and asthma) and the development of retinal vein occlusion (RVO), a major retinal disease that causes visual impairment. METHOD: This study used data obtained from the Korean National Health Insurance Claims database between 2009 and 2018. The association between the three atopic triads (allergic dermatitis, allergic rhinitis, and asthma) and the occurrence of sight-threatening RVO, as determined by diagnostic and treatment codes, were analyzed. Multivariate adjusted Cox regression analysis was used to determine the hazard ratios (HRs) and 95% confidence intervals for RVO development in the presence of allergic disease. RESULTS: In this population-based study, 2,160,195 (54.6%) individuals were male, 1,794,968 (45.4%) were female, and 620,938 (15.7%) were diagnosed with allergic diseases. Patients with either asthma or allergic rhinitis had a greater risk of RVO (adjusted hazard ratio (aHR) = 1.101, 95% confidence interval [CI] = 1.029-1.178 for asthma; aHR = 1.181, 95% CI = 1.147-1.215 for allergic rhinitis) compared to those without asthma or allergic rhinitis; however, patients with atopic dermatitis did not show a significant association with RVO (aHR = 1.071, 95% CI = 0.889-1.290), after adjusting for other risk factors. CONCLUSION: Our study revealed that allergic rhinitis, asthma, and coexisting multiple allergic conditions were associated with an increased risk of RVO. Thus, it may be advisable to suggest an ophthalmological examination for patients with allergies due to the increased possibility of the occurrence of retinal vascular disease.

Microperimetric analysis of eyes after macular hole surgery with indocyanine green staining: a retrospective study.

BACKGROUND: Indocyanine green (ICG) aids in the visualization of the internal limiting membrane (ILM). Retinal damage from ICG dye toxicity has been reported through in vitro and in vivo studies. However, the clinical toxic effect of ICG during macular surgery has not been functionally evaluated. In this study, we evaluated functional and structural changes in retinal sensitivity and retinal thickness associated with ICG toxicity using microperimetry before and after ICG-assisted ILM peeling in patients with macular holes. METHODS: ICG staining was performed only on the macular area below the horizontal line connecting the fovea and optic disc. ILM peeling was performed over the entire macular area inside the vascular arcade. Visual acuity assessment, spectral domain optical coherence tomography, and microperimetry were performed at baseline and one, three, and six months postoperatively. The mean retinal sensitivity of four macular areas was calculated and analyzed. RESULTS: Eleven eyes were included. Macular holes were successfully closed in all patients. Six months postoperatively, retinal sensitivity improved insignificantly in Area 1 (ICG-/ILM-) and Area 2 (ICG-/ILM+) but decreased in Area 4 (ICG+/ILM-). Three months postoperatively, retinal sensitivity significantly decreased in Area 3 (ICG+/ILM+; 26.63 ± 1.80 vs. 25.52 ± 2.08 dB, p = 0.036). However, the statistical significance of this result was lost six months after the surgery (p = 0.059). The change of Gc-IPL thickness in Area 3 was significantly different compared to Area 2 at post-operative 3- and 6-months (p = 0.01, 0.05). CONCLUSIONS: Retinal sensitivity decreased three months after ICG-assisted ILM peeling. However, the statistical significance was lost six months after surgery. ICG staining can be performed with caution during macular hole surgery.

Microperimetric evaluation for different methods of epiretinal membrane surgery.

PURPOSE: To investigate the anatomic and functional outcomes using microperimetry for the surgical methods for idiopathic epiretinal membranes (ERM). METHODS: This retrospective study included 41 eyes from 41 patients. All patients underwent combined epiretinal membrane and cataract surgery. Best-corrected visual acuity (BCVA), optical coherence tomography, and microperimetry were performed before and 6 months and 1 year after surgery. The patients were divided into 3 groups; "ERM removal only without indocyanine green (ICG) staining", "ERM and internal limiting membrane (ILM) removal without ICG staining", and "ERM and ILM removal with ICG staining". RESULTS: Preoperatively, the ages, BCVAs, central macular thickness (CMT), and mean retinal sensitivities of central 6° (MRSs) of the groups were not significantly different (p > 0.05). Postoperatively, the MRSs of the "ERM removal only without ICG staining" and "ERM and ILM removal without ICG staining" groups were not significantly different (p > 0.05). The MRSs of the "ERM and ILM removal without ICG staining" and "ERM and ILM removal with ICG staining" groups were not significantly different (p > 0.05). However, the MRSs of the "ERM and ILM removal with ICG staining" group significantly reduced than "ERM removal only without ICG staining" group (p < 0.05). CONCLUSION: This retrospective study found reduced retinal sensitivity in ERM and ILM removal with ICG staining group compared to ERM removal only without ICG staining. Further studies with larger sample sizes are required.

LONG-TERM ANALYSIS OF INTRASCLERAL FIXATION OF INTRAOCULAR LENS: Trocar-Cannula-Based Sutureless Intrascleral Fixation Versus Sutured Scleral Fixation.

PURPOSE: To compare the long-term outcomes of sutureless intrascleral fixation of the intraocular lens versus sutured scleral fixation. METHODS: The authors retrospectively analyzed the medical records of patients who underwent intrascleral fixation of the intraocular lens using two different techniques: trocar-cannula-based sutureless fixation and sutured scleral fixation. Clinical outcomes were compared before and 1-, 3-, 6-, and 12-month follow-ups after the operation. RESULTS: A total of 51 patients were followed over a 12-month period after the operation, including 28 eyes in the sutureless group and 23 eyes in the sutured group. Best-corrected visual acuity and spherical equivalent values reached targeted values faster in the sutureless scleral fixation of the intraocular lens. However, no significant difference was observed between the two groups. For intraocular lens capture, there was a statistically significant difference observed in the incidence of postoperative complications, which was demonstrated by one eye in the sutureless group and seven in the sutured group ( P = 0.009). To exclude the effect of corneal astigmatism, surgically induced astigmatism was calculated based on the astigmatism value 1 year after surgery. It was found that the sutureless technique significantly reduced the occurrence of astigmatism (2.43 ± 1.42 vs. 1.65 ± 0.94, P = 0.031). CONCLUSION: In a 1-year follow-up period, the trocar-cannula-based sutureless technique was reliable and effective. Sutureless fixation was associated with fewer postoperative complications and lower surgically induced astigmatism values than those with sutured fixation.

Response to brolucizumab treatment for refractory serous pigment epithelial detachment secondary to polypoidal choroidal vasculopathy.

PURPOSE: To report the efficacy and safety of brolucizumab in the treatment of refractory serous pigment epithelial detachment (PED) secondary to polypoidal choroidal vasculopathy (PCV). METHODS: Twenty-six eyes of 26 patients were included. Intravitreal brolucizumab 6.0 mg was administered, followed by pro re nata (PRN) retreatment at monthly follow-ups. All patients underwent spectralis domain optical coherence tomography (SD-OCT), fluorescein angiography, and indocyanine green angiography before the first brolucizumab injection. SD-OCT was repeated at follow-up visits. The height and width of the serous PEDs, measured using SD-OCT, were analyzed. RESULTS: The number of previous anti-VEGF injections was 12.3 ± 15.0. During brolucizumab treatment, anatomical improvement was achieved and maintained in the height and width of the PEDs (p < 0.05). However, the visual outcome did not improve significantly (p > 0.05). A good response was achieved in 69.2% of eyes at 1 month and at the last visit. Relapse and complete resolution were observed in 27.8 and 23.1% of patients, respectively. The number of brolucizumab injections was 2.00 ± 0.85. Intraocular inflammation, vascular obstruction, and retinal pigment epithelial tears were not observed. CONCLUSION: Intravitreal brolucizumab may be an effective and safe treatment option for refractory serous PEDs in patients with PCV.

Evaluation of the microperimetry in eyes with cuticular drusen.

Retinal sensitivity may vary by subtypes of cuticular drusen. This retrospective study included 52 eyes of 32 patients with cuticular drusen. All the patients underwent assessment of best-corrected visual acuity (BCVA), spectral-domain optical coherence tomography (SD-OCT), color fundus photography, fluorescein angiography, fundus autofluorescence, and microperimetry. The area occupied by drusen was counted using microperimetry. The cuticular drusen subtype was classified into 3 groups based on the SD-OCT findings. Age, BCVA, pattern standard deviation, area occupied by drusen, pupil size, and the false-positive rate were not significantly different (p > 0.05) according to the cuticular drusen type. The mean retinal sensitivity (MRS) (p = 0.063) and mean deviation (MD) (p = 0.098) showed marginally significant differences among the groups. In the subgroup analyses, type 1 and type 3 cuticular drusen showed significant differences in the MD (- 1.8 ± 2.1 vs - 5.1 ± 5.3; p = 0.011) and MRS (25.1 ± 2.2 vs 21.3 ± 5.7; p = 0.016) without differences in age, BCVA, or the area occupied by drusen (p > 0.05). The results indicate that depending on the subtypes of cuticular drusen type, the deterioration of retinal sensitivity is more likely to occur than decreased vision.

Analysis of Korean Retinal Specialists' Opinions on Implanting Diffractive Multifocal Intraocular Lenses in Eyes with Underlying Retinal Diseases.

Multifocal intraocular lenses (MF-IOLs) are increasingly implanted as the need for good near- and intermediate-distance vision increases. Although retinal disease is known to be a relative contraindication for MF-IOL implantation, there are no detailed guidelines for MF-IOL implantation with respect to the type and severity of retinal diseases/statuses. In this study, because retinal diseases can affect the performance of MF-IOLs, we analyzed the opinions of 111 retinal specialists, who were members of the Korean Retina Society, on the implantation of diffractive MF-IOLs in eyes with 15 retinal diseases/statuses using a web-based survey. For each underlying condition, retinal specialists were asked to rate their approval regarding implantation of MF-IOLs on a scale from 1 (completely disapprove) to 7 (completely approve), under the assumption that there were no known contraindications except for a given retinal disease/status. As a result, retinal specialists disapproved MF-IOL implantation (median value of Likert score < 4) in the eyes with wet age-related macular degeneration, dry age-related macular degeneration with geographic atrophy, proliferative diabetic retinopathy, nonproliferative diabetic retinopathy with macular edema, previous macula-off retinal detachment, previous retinal vein occlusion, and epiretinal membrane, but the scores varied by disease/status. The factors that affected the specialists' opinions were the type of practice and the frequency of MF-IOL implantation (p = 0.013 and p = 0.021, respectively; one-way ANOVA).

Age-related macular degeneration eyes presenting with cuticular drusen and reticular pseudodrusen.

This study aimed to describe the clinical characteristics of age-related macular degeneration (AMD) eyes with both cuticular drusen (CD) and reticular pseudodrusen (RPD). Clinical records of patients diagnosed with CD or RPD with multimodal imaging was reviewed for patients diagnosed with both CD and RPD. The distribution patterns of CD (macular and diffuse type) and RPD (localized, intermediate, and diffuse type), presence of soft drusen, large drusen (> 200 µm), variant subretinal drusenoid deposits, and macular complications were investigated. Of the 220 eyes of 110 patients diagnosed with CD and 926 eyes of 463 patients diagnosed with RPD, 13 eyes of seven patients met the diagnostic criteria for both CD and RPD. The mean age at initial presentation was 71.4 ± 8.8 years and six patients were female. The mean subfoveal choroidal thickness was 143.8 ± 25.1 µm. The distribution of CD was of the macular type in all eyes. Distribution of RPD was localized in 11 eyes (84.6%) and intermediate in two eyes (15.4%). Soft drusen, large drusen, and variant subretinal drusenoid deposits were present in 13 (100%), 12 (92.3%) and, seven (53.8%) eyes, respectively. Macular neovascularization was observed in two eyes (15.4%). CD and RPD can coexist in eyes with AMD. Multimodal imaging should be used for AMD eyes with features suggestive of CD and RPD, considering the high likelihood of developing late AMD.

INTRAOCULAR LENS MALPOSITION AFTER SUTURELESS INTRASCLERAL FIXATION OF INTRAOCULAR LENS.

PURPOSE: To introduce cases of intraocular lens (IOL) malposition after sutureless intrascleral fixation. METHODS: We retrospectively analyzed the medical records of patients who underwent sutureless intrascleral fixation. Cases with postoperative IOL requiring reoperation were analyzed further. RESULTS: Of the 48 eyes that underwent sutureless intrascleral fixation of their IOL, seven eyes had postoperative IOL malposition and underwent reoperation (14.6%). There was no difference in the clinical results between the intravitreal (33 eyes) and intracameral (15 eyes) techniques, but IOL malposition requiring reoperation was more frequent in the latter (2 cases [6.1%] vs. 5 cases [33.3%], P = 0.024). In the 7 eyes that required reoperation, the visual acuity before reoperation was 0.9 ± 0.6 logMAR (20/159), whereas astigmatism was -4.8 ± 3.2 diopters. The visual acuity and cylindrical error improved to 0.1 ± 0.2 logMAR (20/25) and -2.4 ± 2.3 diopters, respectively, at 6 months after the secondary operation. CONCLUSION: In 14.6% of the patients who underwent sutureless intrascleral fixation of the IOL, IOL malposition developed and reoperation was performed. With the intravitreal technique, which uses a wider space than the intracameral technique, the frequency of postoperative IOL malposition could be reduced.

Acute symptomatic vitreous floaters assessed with ultra-wide field scanning laser ophthalmoscopy and spectral domain optical coherence tomography.

To describe the eyes with vitreous floaters and to analyze the development of acute symptomatic posterior vitreous detachment (PVD). A retrospective review of medical records was performed on patients with the vitreous floater developed for the first time of their life. Peripapillary vitreous opacity (pVO) was searched in Ultra-wide field (UWF) scanning laser ophthalmoscopy and PVD stage was assessed through spectral-domain optical coherence tomography (SD-OCT). 196 patients (55 males and 141 females), who were 58.4 (± 9.1) years old, visited a retinal clinic 9.4 (± 9.1) days after they experienced vitreous floaters. In 196 eyes, pVO was noticed in 122 eyes (62.2%) at UWF. In 106 eyes where SD-OCT data were available, PVD was noticed in 100 eyes (94.3%). Symptomatic eyes showed more advanced stage of PVD (p < 0.001) than symptom free eyes. Eyes with floaters were more myopic (- 0.7 ± 2.2D vs - 0.5 ± 1.9D, p = 0.02), and had lower intraocular pressure (IOP) (14.7 ± 3.2 mmHg vs 15.2 ± 3.0 mmHg, p = 0.02) than the other symptom free eyes. In patients with first floater symptoms, PVD was in progress in most of the eyes not only the symptomatic eyes but also on the contralateral symptom free eyes. Eyes with vitreous floaters were more myopic and had lower IOP than the opposite symptom free eyes.

Heritability of macular ganglion cell inner plexiform layer thickness as determined by optical coherence tomography: the Healthy Twin Study.

PURPOSE: To evaluate genetic influence on macular ganglion cell inner plexiform layer (GCIPL) thickness. METHODS: Macular GCIPL thickness was measured with optical coherence tomography in nine macular subfields defined by the E TDRS. Intraclass correlation coefficients (ICC) of GCIPL thickness by different types of family relationships were estimated to assess intrafamilial resemblance. Then, heritability of GCIPL thickness was estimated. RESULTS: Three hundred and sixty-one Korean adults from 89 families with normal healthy eyes were included. GCIPL thickness was highest in inner subfields and lowest in fovea. Monozygotic twin pairs showed significantly higher ICCs of GCIPL thickness in all subfields compared to those in parent-offspring pairs and sibling pairs. GCIPL thickness was highly heritable in the centre (0.71) and outer subfields but moderate to highly heritable in inner subfields. Heritability of GCIPL thickness in outer subfields was 0.69, 0.67, 0.72 and 0.68 for superior, inferior, temporal and nasal fields, respectively. Heritability of GCIPL thickness in inner subfields was 0.55, 0.56, 0.75 and 050 for superior, inferior, temporal and nasal subfields, respectively. CONCLUSION: Macular GCIPL thickness is significantly influenced by genetic factors. It varies according to subfields with moderate to high heritability in all subfields.

COMPARISON OF SCLERAL FIXATION OF INTRAOCULAR LENS: Sutureless Intrascleral Fixation Versus Conventional Sutured Scleral Fixation.

PURPOSE: To compare the clinical outcomes of sutured scleral and sutureless intrascleral fixations of the intraocular lens. METHODS: Medical records of patients who underwent sutureless intrascleral fixation (sutureless group) and the conventional sutured scleral fixation (sutured group) were retrospectively reviewed. Patient demographics and the clinical outcomes of the two techniques were compared before and 1, 3, and 6 months after surgery. RESULTS: Seventy patients were followed up for 6 months after the surgery: 25 patients in the sutureless group (25 eyes) and 45 in the sutured group (45 eyes). Surgery time was shorter in the sutureless group than that in the sutured group (73.00 ± 15.68 vs. 107.39 ± 25.30 minutes, P < 0.001). The visual acuity gradually improved throughout the postoperative period in both groups, and a faster visual acuity recovery was observed in the sutureless group. The cylindrical error at 6 months after the surgery was significantly lower in the sutureless group than that in the sutured group (-1.33 ± 0.55 vs. -2.29 ± 1.19 diopter, P < 0.001). CONCLUSION: Sutureless intrascleral fixation is an effective and reliable surgical technique that provides more favorable visual and refractive outcomes than the conventional sutured scleral fixation method.

Genetic Influence on Choroidal Volume.

PURPOSE: To evaluate the degree of genetic influence on macular choroidal volume. DESIGN: A cross-sectional twin and family study. METHODS: In total, 353 Korean adults with healthy eyes from 78 households with 2 or more family members were included in the study. Macular choroidal volume was measured using spectral-domain optical coherence tomography with enhanced depth imaging at 9 macular subfields defined by the ETDRS. Demographics and clinical characteristics were investigated, including age, sex, axial length, hypertension, diabetes, drinking habits, and smoking status. The associations of these factors with macular choroidal volume were assessed using univariate and subsequent multivariate regression analyses while accounting for family structure. The heritability estimates of macular choroidal volume in total and at each of the 9 macular subfields were calculated after adjusting the covariates. RESULTS: Patients who were younger, male, and had a shorter axial length showed associations with greater choroidal volume (P < .001 for all 3 independent variables). The covariates-adjusted heritability (±standard error) of the total macular choroidal volume was 0.76 ± 0.06, and the heritabilities of choroidal volume at each subfield ranged from 0.55 ± 0.09 (inner temporal subfield) to 0.77 ± 0.08 (inner superior subfield). CONCLUSION: The macular choroidal volume is highly heritable.

Clinical manifestations of cuticular drusen in Korean patients.

Cuticular drusen show some similarities to and differences from soft drusen in age-related macular degeneration (AMD) and might thus be a unique AMD subtype. Previous studies on cuticular drusen were performed mainly in white ethnic groups, but AMD shows ethnic differences. We investigated clinical manifestations of cuticular drusen in Korean patients to evaluate possible ethnic differences. Clinical records of Korean patients with cuticular drusen were retrospectively reviewed. Fundus distribution pattern, imaging features, and presence of large drusen, drusenoid pigment epithelial detachment (PED), and macular complications, including geographic atrophy (GA), choroidal neovascularization (CNV), and acquired vitelliform lesion (AVL), were assessed via multimodal imaging in 162 eyes with cuticular drusen (n = 81 patients; 67 females; mean age: 66.6 ± 9.1 years). Diffuse distribution was found in 61.7% and peripapillary involvement in 75.3% of eyes. Large drusen, drusenoid PED, GA, CNV, and AVL were observed in 59.3%, 26.5%, 18.5%, 3.7%, and 1.2% of eyes, respectively. The macular complication prevalence was similar between patients ≤ 60 and those > 60 years old. In Korean patients, cuticular drusen were less frequently associated with macular complications than in white patients, and the proportion of macular complications differed significantly, with AVL representing an uncommon complication.

Heritability of Inner Retinal Layer and Outer Retinal Layer Thickness: The Healthy Twin Study.

The purpose of the study is to evaluate the heritability of inner retinal layer (IRL) and outer retinal layer (ORL) thicknesses in the healthy Korean population. This was a cross-sectional, twin and family study. We included 374 Korean adults with healthy eyes from 89 families. IRL thickness (from the internal limiting membrane to the external limiting membrane) and ORL thickness (from the external limiting membrane to the outer border of the retinal pigment epithelium layer) were measured in the nine macular subfields as defined by the Early Treatment of Diabetic Retinopathy Study using optical coherence tomography. The heritability on IRL and ORL thicknesses were investigated using a variance decomposition model. The heritability of IRL thickness was 0.87, 0.58, 0.85, 0.89, and 0.74 for the central, inner superior, inner inferior, inner temporal, inner nasal subfields, respectively; and 0.62, 0.83, 0.62, and 0.60 for the outer superior, outer inferior, outer temporal, outer nasal subfields, respectively. The heritability of ORL thickness was 0.56, 0.75, 0.66, 0.72, and 0.56 for the central, inner superior, inner inferior, inner temporal, inner nasal subfields, respectively; and 0.64, 0.63, 0.73, 0.54 for the outer superior, outer inferior, outer temporal, and outer nasal subfields, respectively. The heritability estimates of IRL thickness and ORL thickness ranged from moderate to high. The IRL thickness at the central, inner temporal, and inner inferior subfields had particularly high heritability.

Genetic influence on macular retinal nerve fibre layer thickness according to retinal subfield.

BACKGROUND/AIM: Characterising genetic effect on macular retinal nerve fibre layer (RNFL) is needed to obtain better understanding of various retinopathies and optic neuropathies. The purpose of this study was to evaluate genetic influence on macular RNFL thickness. METHODS: This is a cross-sectional, twin and family study. Three hundred and sixty-two Korean adults with healthy eyes were included in the study from 79 households with two or more family members. Macular RNFL thickness was measured with optical coherence tomography at nine macular subfields defined by the ETDRS. Intraclass correlation coefficients (ICCs) were estimated to assess intrafamilial resemblance of RNFL thickness by different types of family relationship. Heritability of RNFL thickness was evaluated using variance decomposition model. RESULTS: RNFL thickness increased from central subfield to outer subfields. Temporal quadrant RNFL was thinner compared with other quadrants. Monozygotic twin pairs showed the highest ICCs of RNFL thickness, although the ICC level varied across different subfields. Heritability of RNFL thickness was the highest at central subfield (0.81). RNFL thicknesses of outer subfields were moderately to highly heritable: 0.53, 0.71, 0.47 and 0.66 for superior, inferior, temporal and nasal fields, respectively. RNFL thicknesses at inner subfields showed the lowest heritability: 0.21, 0.24, 0.27 and 0.27 for superior, inferior, temporal and nasal subfields, respectively. CONCLUSION: Macular RNFL thickness is significantly influenced by genetic factors. It varies largely by subfields with the highest heritability at the central subfield and a relatively lower heritability at inner subfields.