Ophthalmoscopic assessment of the retinal nerve fiber layer. The Beijing Eye Study

Lamina Cribrosa Configurations in Highly Myopic and Non-Highly Myopic Eyes: The Beijing Eye Study

Purpose

The purpose of this study was to examine characteristics of lamina cribrosa (LC) configuration in highly myopic (HM) eyes.

Methods

Participants from the Beijing Eye Study 2011, free of optic nerve or retinal diseases, were randomly selected to examine LC depth (LCD) and LC tilt (LCT) using three-dimensional optical coherent tomography images of the optic nerve head (ONH). LCD and LCT were measured as the distance and angle between the LC plane with two reference planes, including the Bruch's membrane opening (BMO) plane and the peripapillary sclera (PPS) plane, respectively. Each parameter was measured in both horizontal and vertical B-scans.

Results

The study included 685 individuals (685 eyes) aged 59.6 ± 7.7 years, including 72 HM eyes and 613 non-HM eyes. LCD measurements showed no significant differences between HM eyes and non-HM eyes in both horizontal (LCD-BMO = 421.83 ± 107.86 µm for HM eyes vs. 447.24 ± 104.94 µm for non-HM eyes, P = 0.18; and LCD-PPS = 406.39 ± 127.69 µm vs. 394.00 ± 101.64 µm, P = 1.00) and vertical directions (LCD-BMO = 435.78 ± 101.29 µm vs. 450.97 ± 106.54 µm, P = 0.70; and LCD-PPS = 401.62 ± 109.9 µm vs. 379.85 ± 110.35 µm, P = 0.35). However, the LCT was significantly more negative (tilted) in HM eyes than in non-HM eyes horizontally (LCT-BMO = -4.38 ± 5.94 degrees vs. -0.04 ± 5.86 degrees, P < 0.001; and LCT-PPS = -3.16 ± 5.23 degrees vs. -0.94 ± 4.71 degrees, P = 0.003), but not vertically (P = 1.00).

Conclusions

Although LCD did not differ significantly between HM and non-HM eyes, LCT was more negative in HM eyes, suggesting that the temporal or inferior side of the LC was closer to the reference plane. These findings provide insights into morphological and structural changes in the LC and ONH between HM and non-HM eyes.

Association between localized retinal nerve fiber layer defects in nonglaucomatous eyes and metabolic syndrome: a propensity score-matched analysis

Background

We investigated the association between metabolic syndrome and localized retinal nerve fiber layer (RNFL) defects in nonglaucomatous subjects.

Methods

We examined 20,385 adults who visited the Health Promotion Center of Seoul St. Mary's Hospital between May 2015 and April 2016. After excluding those with known glaucoma or glaucomatous optic discs, subjects with and without localized RNFL defects were 1:5 propensity score matched. Metabolic syndrome components, including central obesity, elevated triglyceride, reduced high-density lipoprotein (HDL) cholesterol, elevated blood pressure (BP), and elevated fasting glucose, were compared between two groups. We performed logistic regression to investigate the association between RNFL defects and each component of metabolic syndrome and the number of metabolic syndrome components.

Results

Subjects with RNFL defects showed higher waist-to-hip ratios, systolic BP (SBP) and diastolic BP (DBP), fasting blood glucose, and hemoglobin A1c (HbA1c) levels than did those without RNFL defects both before and after propensity score matching. The number of metabolic syndrome components was significantly greater in those with RNFL defects (1.66±1.35) than in those without (1.27±1.32, P<0.01). In multivariate logistic regression, the odds ratio (OR) of RNFL defects was significantly increased in subjects with central obesity [OR =1.53, 95% confidence interval (CI): 1.11-2.13], elevated BP (OR =1.50, 95% CI: 1.09-2.05), and an elevated fasting glucose level (OR =1.42, 95% CI: 1.03-1.97). An increased number of metabolic syndrome components was associated with a higher risk of RNFL defects.

Conclusions

Localized RNFL defects in nonglaucomatous subjects are associated with metabolic syndrome components, including central obesity, elevated BP, and an elevated fasting glucose level, suggesting that comorbid metabolic syndrome should be considered when evaluating subjects with RNFL defects.

Variation in Retinal Nerve Fiber Layer and Ganglion Cell Complex Associated With Optic Nerve Head Size in Healthy Eyes

Purpose

To investigate whether the retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) change with optic nerve head (ONH) size in healthy eyes.

Methods

This cross-sectional observational study recruited participants aged ≥50 years. Participants underwent optical coherence tomography-assisted measurements of the peripapillary RNFL and macular GCC and were divided into small, medium, and large ONH groups according to optic disc area (≤1.9 mm2, >1.9 mm2 and ≤2.4 mm2, and >2.4 mm2, respectively). The groups were compared for RNFL and GCC. Linear regression models were used to evaluate the correlation of RNFL and GCC with ocular and systemic factors.

Results

There were 366 participants. The whole, temporal, and superior RNFLs were significantly different among the groups (P = 0.035, 0.034, and 0.013, respectively) with no significant difference in the nasal and inferior RNFL (P = 0.214, 0.267, respectively). The average, superior, and inferior GCCs were not significantly different among the groups (P = 0.583, 0.467, and 0.820, respectively). Thinner RNFL was independently associated with older age (P = 0.003), male sex (P = 0.018), smaller disc area (P < 0.001), higher vertical cup disc ratio (VCDR) (P < 0.001), and larger maximum cup depth (P = 0.007); thinner GCC was independently associated with older age (P = 0.018), larger best-corrected visual acuity (P = 0.023), and higher VCDR (P = 0.002).

Conclusions

RNFL but not GCC significantly increased with ONH size in healthy eyes. GCC may be more suitable than RNFL for evaluating early glaucoma in patients with large or small ONH.

Translational Relevance

GCC may be a better index than RNFL for early glaucoma evaluation in patients with large or small ONH.

Retinal nerve fibre layer thickness measured with SD-OCT in a population-based study: the Handan Eye Study

PURPOSE

To examine the normative profile of retinal nerve fibre layer (RNFL) thickness and ocular parameters based on spectral-domain optical coherence tomography (SD-OCT) and its associations with related parameters among the Chinese population.

METHODS

This population-based cohort Handan Eye Study (HES) recruited participants aged≥30 years. All subjects underwent a standardised ophthalmic examination. Peripapillary RNFL thickness was obtained using SD-OCT. Mixed linear models were adopted to evaluate the correlation of RNFL thickness with ocular parameters as well as systemic factors. R V.3.6.1 software was used for statistical analysis.

RESULTS

3509 subjects (7024 eyes) with the average age of 55.54±10.37 were collected in this analysis. Overall mean RNFL thickness measured was 113.46±10.90 µm, and the thickest quadrant of parapapillary RNFL was the inferior quadrant, followed by the superior quadrant, the nasal quadrant and the temporal quadrant. In the multivariate linear regression model, thinner RNFL thickness was remarkable association with male (p<0.001), older age (p<0.001), increased body mass index (>30, p=0.018), absence of diabetes (p=0.009), history of cataract surgery (p=0.001), higher intraocular pressure (p=0.007), lower spherical equivalent (p<0.001) and increased axial length (p=0.048).

CONCLUSIONS

In non-glaucoma individuals, this difference of RNFL thickness in Chinese population should be noted in making disease diagnoses. Meanwhile, multiple ocular and systemic factors are closely related to the thickness of RNFL. Our findings further emphasise the need to demonstrate ethnic differences in RNFL thickness and the specificity of associated ocular and systemic factors, as well as to develop better normative databases worldwide.

TRIAL REGISTRATION NUMBER

HES was registered in Chinese Clinical Trial Registry website, and the registry number was ChiCTR-EOC-17013214.

Quantification of localised vascular wedge-shaped defects in glaucoma

BACKGROUND

Vascular dysfunction plays a considerable role in glaucoma pathogenesis. Previous glaucoma case studies described localised wedge-shaped vascular defects, similar to retinal nerve fibre layer (RNFL) wedge defects. This study investigates the prevalence and quantification of this vessel loss, in relation to primary open angle glaucoma (POAG) parameters.

METHODS

This study included 608 eyes (351 participants): 192 PROGRESSA study participants (342 eyes) with suspect, preperimetric or early manifest POAG, observed for vascular wedge defect presence (cohort one); an additional 114 individuals (cohort two-208 eyes) with POAG at various stages of progression for wedge characterisation; and 38 controls (56 eyes). Vascular wedge defects were observed using optical coherence tomography angiography (OCTA). Wedge parameters and vessel densities were quantified using ImageJ software. RNFL and ganglion cell layer inner plexiform layer (GCLIPL) from OCT scans, and mean deviation (Humphrey visual field 24-2) were also assessed.

RESULTS

Vascular wedge defects were found in 45/342 eyes (13.2%) in cohort one, in 41/208 eyes (19.7%) in cohort two and were not found in controls. Wedge defects were mostly inferotemporal (80%), and present at all disease stages. They were associated with visual field loss in the opposite hemisphere, thinner RNFL (p < 0.001), thinner GCLIPL (p = 0.003), and focal RNFL loss corresponding with the vascular defect region.

CONCLUSION

Vascular wedge defects are present at all POAG stages even before functional change and are strongly concordant with focal RNFL loss. Further research is needed to explore these defects in particular their temporal relationship with clinical measures of POAG.

Association between localised retinal nerve fibre layer defects and cardiovascular risk factors

Localised retinal nerve fibre layer defects (RNFLDs) are reported to indicate the degree of glaucomatous damage but can also be sequelae of retinal vascular insufficiency as a result of systemic vascular factors. We investigated the association between RNFLDs and cardiovascular risk factors. RNFLDs were detected in 440 (29.2%) of 1508 subjects. The presence of RNFLDs was associated with higher HbA_1c (odds ratio [OR] 1.289, p < 0.001), higher 24-h mean systolic blood pressure (SBP; OR 1.013, p < 0.005), and lower estimated glomerular filtration rate (eGFR; OR 0.995, p < 0.005). An increasing number of RNFLDs was correlated with higher SBP (r = 0.186, p < 0.001), higher HbA_1c (r = 0.128, p < 0.010), lower eGFR (r = −0.112, p < 0.020), and younger age (r = −0.303, p < 0.001). Subjects with RNFLDs had a higher predicted 10-year risk of atherosclerotic cardiovascular disease than did those without RNFLDs (9.7% vs 7.9%, p = 0.008 in middle-aged subjects, 25.6% vs 23.2%, p = 0.040 in older subjects). In conclusion, RNFLDs are associated with SBP, eGFR, and HbA_1c. Concomitant cardiovascular risk factors should be considered when evaluating patients with localised RNFLDs.

Association of ocular, cardiovascular, morphometric and lifestyle parameters with retinal nerve fibre layer thickness

Background

Glaucoma is a neurodegenerative disease, leading to thinning of the retinal nerve fibre layer (RNFL). The exact influence of ocular, cardiovascular, morphometric, lifestyle and cognitive factors on RNFL thickness (RNFLT) is unknown and was analysed in a subgroup of the Gutenberg Health Study (GHS).

Methods

Global peripapillary RNFLT was measured in 3224 eyes of 1973 subjects (49% female) using spectral-domain optical coherence tomography (SD-OCT). The association of age, sex, ocular, cardiovascular, morphometric, lifestyle and cognitive factors on RNFLT was analysed using Pearson correlation coefficient and fitting a linear mixed model.

Results

In the univariable analysis highest correlations were found for axial length (r = -0.27), spherical equivalent (r = 0.24), and glaucoma (r = -0.15) (p<0.0001, respectively). Other significant correlations with RNFLT were found for age, sex, intraocular pressure, systemic hypertension and systolic blood pressure, previous eye surgery, cholesterol, homocysteine, history of coronary artery disease, history of myocardial infarction, apnoea, diabetes and alcohol intake, p<0.05, respectively. Body length, body weight, BMI, diastolic blood pressure, blood glucose, HbA1c, history of apoplexy, cognitive function, peripheral artery disease, tinnitus, migraine, nicotine intake, central corneal thickness, and pseudophakia were not significantly correlated with RNFLT. The regression model revealed a significant relationship between RNFLT and age in decades (p<0.02), spherical equivalent (p<0.0001), axial length (p<0.0001), glaucoma (p<0.0001), tinnitus (p = 0.04), apnoea (p = 0.047), homocysteine (p = 0.05) and alcohol intake >10g/d for women and >20g/d for men (p = 0.02). Glaucoma, apnoea, higher homocysteine, higher alcohol intake and higher axial length as well as age were related to decreased RNFLT while higher spherical equivalent or history for tinnitus were related to thicker RNFL.

Conclusion

RNFLT is related to age, ocular parameters and lifestyle factors. Considering these parameters in normative databases could improve the evaluation of peripapillary RNFLT. It is necessary to evaluate if a reduction of alcohol intake as well as the therapy of apnea or high homocysteine levels could positively influence RNFLT.

Prevalence of retinal nerve fiber layer defects: The Korea National Health and Nutrition Examination Survey 2008-2012

Purpose

To investigate the prevalence and associated factors of retinal nerve fiber layer defects (RNFLDs) in a Korean population.

Methods

The Korea National Health and Nutrition Examination Survey (KNHANES) is a population-based study using a complex, stratified, multistage, probability-cluster survey. We performed a review of 2008–2012 data from the KNHANES. Two masked ophthalmologists evaluated fundus photography to detect RNFLDs. All participants underwent ocular and systemic evaluations.

Results

A total of 28,637 subjects aged ≥ 19 years with at least one evaluable fundus photograph were enrolled. The estimated prevalence of RNFLDs in this Korean population was 4.8% (95% confidence interval, 4.4%–5.3%). The estimated percentages of glaucomatous RNFLD and non-glaucomatous RNFLD subjects were 34.4% and 65.6%, respectively. In a multivariate analysis, the prevalence of RNFLDs was significantly associated with older age (P < 0.001), male gender (P = 0.047), glycosylated hemoglobin (P = 0.048), disc hemorrhage (P = 0.016), ISNT rule (P < 0.001), and vertical cup to disc ratio (P < 0.001).

Conclusions

The prevalence of RNFLDs in a large Korean population-based sample with a minimum age of 19 years was 4.8%. RNFLD prevalence was associated with old age, male gender, glycosylated hemoglobin, disc hemorrhage, and glaucomatous optic disc.

Determinants of peripapillary retinal nerve fiber layer thickness regarding ocular and systemic parameters - the MIPH Eye&Health Study

BACKGROUND

Optical coherence tomography (OCT) allows quantitative image analysis of retinal tissue in vivo. Peripapillary retinal nerve fiber layer (pRNFL) thickness is widely used for evaluation of retinal nerve fiber rarefaction in several optic neuropathies. This study evaluates associations of pRNFL thickness in healthy adult subjects in order to evaluate influencing factors.

METHODS

A cross-sectional study was performed in a working-age population. Only eyes without detectable ocular pathologies were included in the analysis. Among analyzed systemic cardiovascular parameters were age, gender, body-mass index, mean arterial blood pressure, HbA1c, high- and low-density-lipoproteins, and triglycerides. A comprehensive ophthalmological examination including refraction, tonometry, keratometry, and central corneal thickness measurmentwas performed. In addition, pRNFL thickness was imaged by spectral-domain OCT. Univariable and multivariable associations of pRNFL thickness in all four quadrants and on average with systemic and ocular parameters were calculated using a generalized estimating equation model.

RESULTS

Three hundred and six subjects were included. pRNFL thickness measurements showed a significant association with spherical equivalent: pRNFL thickness decreased with increasing myopia in all quadrants (multivariable regression coefficients Beta: superior: 1.16, 95 % CI [0.62;1.71], p < 0.001; temporal: 0.87, [0.33;1.41], p = 0.001; inferior: 1.80, [1.18;2.42], p < 0.001; nasal: 2.60, [2.01;3.20], p < 0.001) and on average (1.51, [1.20;1.82], p < 0.001). A thicker central cornea thickness was related to lower pRNFL in the superior (-0.05, [-0.10; -0.01], p = 0.01), the inferior quadrant (-0.05, [-0.10;0.00], p = 0.03) and on average (-0.04, [-0.07; -0.01], p = 0.02). All other parameters were not  associated.

CONCLUSION

Our findings highlight the importance of refraction when evaluating pRNFL thickness and its independence from other systemic parameters.

Sectorial loss of retinal ganglion cells in inherited photoreceptor degeneration is due to RGC death

Aims

To investigate the cause of retinal ganglion cell (RGC) loss in dystrophic aged Royal College of Surgeons (RCS) rats.

Methods

RCS-p+ (dystrophic) female rats of postnatal times (P365, P450 and P540) and age-matched RCS-p1 rdy+ (non-dystrophic) rats were used. In whole-mounted retinas, RGCs were doubly labelled with Fluorogold (FG) retrogradely transported from the superior colliculi and Brn3a immunohistochemistry. RGC axons were labelled with anti-neurofilament antibodies. Automatic image analysis techniques allowed quantification of the total population of RGCs per retina and construction of isodensity maps to investigate RGC topology.

Results

Dystrophic retinas showed at all times studied wedge-shaped sectors devoid of FG⁺ and Brn3a⁺ RGCs. These sectors were also devoid of neurofilament-labelled axons. The total number of FG⁺RGC and Brn3a⁺RGC per retina was significantly smaller in dystrophic rats at P540, revealing RGC death at this age. The total number of FG⁺RGCs was smaller than those of Brn3a⁺RGCs at P540, indicating a disturbance of the retrograde axonal transport at this age.

Conclusions

RGC double labelling documents that sectorial RGC loss in aged dystrophic RCS rats is mainly due to RGC death, although a deficit of the retrograde axonal transport exists also at the more advanced ages.