Compare of optic coherence tomography parameters in recreational synthetic tetrahydrocannabinol use and healthy control

PURPOSE

To evaluate retinal thickness (RT), retinal nerve fiber layer thickness (RNFLT), and choroidal thickness (CT) changes in synthetic cannabinoid (SC) users.

METHODS

This prospective study evaluated the RT, RNFLT, and CT values of 56 SC users and 58 healthy controls. The individuals using SCs were referred to us by our hospital's forensic medicine department. Retinal and choroidal images were obtained using spectral-domain optical coherence tomography (OCT). Measurements (one subfoveal, three temporals, three nasal) were taken at 500 μm intervals up to 1500 μm using the caliper system. Only the right eye was used for subsequent analysis.

RESULTS

Mean ages were 27.7 ± 5.7 years in the SC-user group and 25.4 ± 6.7 in the control group. Subfoveal Global RNFLT was in the SCs group 102.3 ± 10.5 μm and 105.6 ± 20.2 μm in the control group (p = 0.271). Subfoveal CT was in the SC group mean of 316.1 ± 100.2 μm and in the control group mean 346.4 ± 81.8 μm (p = 0.065). RT, T500 (283.3 ± 36.7 μm, 296.6 ± 20.5 μm, p = 0.011) and N1500 (355.1 ± 14.3 μm, 349.3 ± 18.1 μm, p = 0.049) were significantly higher in the SC group than in the control group, respectively.

CONCLUSION

Analysis of OCT findings of individuals who had been using SC for more than one year revealed no statistically significant difference between RNFLT and CT, although N1500 was significantly higher in RT. Further studies in the field of OCT are important to explore the pathology of SC.

Analysis of the Asymmetry between Both Eyes in Early Diagnosis of Glaucoma Combining Features Extracted from Retinal Images and OCTs into Classification Models

This study aims to analyze the asymmetry between both eyes of the same patient for the early diagnosis of glaucoma. Two imaging modalities, retinal fundus images and optical coherence tomographies (OCTs), have been considered in order to compare their different capabilities for glaucoma detection. From retinal fundus images, the difference between cup/disc ratio and the width of the optic rim has been extracted. Analogously, the thickness of the retinal nerve fiber layer has been measured in spectral-domain optical coherence tomographies. These measurements have been considered as asymmetry characteristics between eyes in the modeling of decision trees and support vector machines for the classification of healthy and glaucoma patients. The main contribution of this work is indeed the use of different classification models with both imaging modalities to jointly exploit the strengths of each of these modalities for the same diagnostic purpose based on the asymmetry characteristics between the eyes of the patient. The results show that the optimized classification models provide better performance with OCT asymmetry features between both eyes (sensitivity 80.9%, specificity 88.2%, precision 66.7%, accuracy 86.5%) than with those extracted from retinographies, although a linear relationship has been found between certain asymmetry features extracted from both imaging modalities. Therefore, the resulting performance of the models based on asymmetry features proves their ability to differentiate healthy from glaucoma patients using those metrics. Models trained from fundus characteristics are a useful option as a glaucoma screening method in the healthy population, although with lower performance than those trained from the thickness of the peripapillary retinal nerve fiber layer. In both imaging modalities, the asymmetry of morphological characteristics can be used as a glaucoma indicator, as detailed in this work.

Peripapillary and macular microvasculature features of non-arteritic anterior ischemic optic neuropathy

Purpose

The hallmark of non-arteritic anterior ischemic optic neuropathy (NAION) is vascular compromise to the anterior optic nerve and thinning of the retinal nerve fiber layer (RNFL) and secondary degeneration of the retinal ganglion cell body or thinning of the ganglion cell complex (GCC). This study investigates optical coherence tomography (OCT) and OCT Angiography (OCTA) changes in chronic NAION and identifies imaging biomarkers that best predict disease.

Methods

We performed a retrospective case-control study of 24 chronic NAION eyes (18 patients) and 70 control eyes (45 patients) to compare both whole-eye and regional OCT, OCTA, static perimetry measurements. OCT measurements were quantified automatically using commercial software, and OCTA was analyzed using custom MATLAB script with large vessel removal to measure 154 total parameters per eye.

Results

We confirmed that static perimetry mean deviation (MD) was significantly worse in chronic NAION (-13.53 ± 2.36) than control (-0.47 ± 0.72; P < 0.001) eyes, and NAION eyes had 31 μm thinner RNFL (control: 95.9 ± 25.8 μm; NAION: 64.5 ± 18.0, P < 0.001), and 21.8 μm thinner GCC compared with controls (control: 81.5 ± 4.4 μm; NAION: 59.7 ± 10.5, P < 0.001). Spearman correlation analysis of OCTA parameters reveal that vessel area density (VAD) and flux are highly correlated with visual field MD and OCT measurements. Hierarchical clustering two distinct groups (NAION and control), where standardized measurements of NAION eyes were generally lower than controls. Two-way mixed ANOVAs showed significant interaction between patient status (control and chronic NAION) and structure (optic disk and macula) for annulus VAD and flux values and mean RNFL and GCC thickness. Post-hoc tests showed this effect stems from lower peripapillary values in NAION compared to controls. Separate logistic regression models with LASSO regularization identified VAD and flux are one of the best OCTA parameters for predicting NAION.

Conclusion

Ischemic insult to the optic disk is more severe likely from primary degeneration of the affected peripapillary region while macula is affected by secondary retrograde degeneration and loss of retinal ganglion cells. In addition to OCT measurements, peripapillary and macular vascular parameters such as VAD and flux are good predictors of optic nerve and retinal changes in NAION.

An analysis of macular ganglion cell complex in 7-year-old children in China: the Anyang Childhood Eye Study

BACKGROUND

This study used spectral-domain optical coherence tomography (SD-OCT) imaging to describe the distribution of macular ganglion cell complex (GCC) thickness and its association with ocular and systemic parameters in 7-year-old children in China.

METHODS

The study involved a school-based, cross-sectional analysis of the Anyang Childhood Eye Study (ACES) and included 2,505 first-grade students from urban areas in Anyang, Henan Province, Central China. All participants underwent systemic and ocular examinations. Both GCC and retinal nerve fiber layer (RNFL) thickness were measured using the iVue-100 OCT (Optovue, Fremont, CA, USA). Intraocular pressure (IOP) was recorded with noncontact tonometer (Huvitz, HNT-7000). Axial length (AL) was measured using optical biometry (Lenstar LS 900, Haag-Streit Diagnostics, Koniz, Switzerland).

RESULTS

The mean GCC thickness was 95.31±7.67 µm. GCC thickness had negative associations with AL (r=-0.124, P<0.001), cup-to-disc (C-D) area ratio (r=-0.068, P=0.0033), horizontal C-D (H C-D) ratio (r=-0.048, P=0.0384), and vertical C-D (V C-D) ratio (r=-0.074, P=0.0013). Positive correlations were found with spherical equivalent (SE) (r=0.080, P=0.0001), RNFL thickness (r=0.363, P<0.001), height (r=0.059, P=0.0036), fovea parameters, disc area (r=0.078, P=0.0007), rim area (r=0.115, P<0.001), rim volume (r=0.119, P<0.001), and optic nerve head volume (r=0.097, P<0.001). GCC thickness had no significant association with IOP, age, sex, or weight, waist, or head circumference.

CONCLUSIONS

This study provides normative GCC data for 7-year-old healthy children in China. The findings support an association between GCC and AL, SE, RNFL, height, and C-D ratio in children.

Neurophthalmologic and Orthoptic Ambulatory Assessments Reveal Ocular and Visual Changes in Patients With Early Alzheimer and Parkinson's Disease

Patients with Alzheimer's disease (AD) and Parkinson's disease (PD) develop a progressive decline of visual function. This condition aggravates overall cognitive and motor abilities, is a risk factor for developing hallucinations, and can have a significant influence on general quality of life. Visual problems are common complaints of patients with PD and AD in the early stages of the disease, but they also occur during normal aging, making it difficult to differentiate between normal and pathological conditions. In this respect, their real incidence has remained largely underestimated, and no rehabilitative approaches have been standardized. With the aim to increase awareness for ocular and visual disorders, we collected the main neurophthalmologic and orthoptic parameters, including optical coherence tomography (OCT), in six patients with a diagnosis of PD, six patients with a diagnosis of early AD, and eight control subjects in an easily assessable outpatient setting. We also evaluated the patient's ability to recognize changes in facial expression. Our study demonstrates that visual problems, including blurred vision, diplopia, reading discomfort, photophobia, and glare, are commonly reported in patients with PD and AD. Moreover, abnormal eye alignment and vergence insufficiency were documented in all patients during examination. Despite the small size of the sample, we demonstrated greater ganglion cell and retinal nerve fibers layer (RNFL) damage and a defect of facial emotion recognition in AD/PD patients with respect to a comparable group of normal elderly persons, with peculiarities depending upon the disease. Ocular defects or visual discomfort could be correctly evaluated in these patients and possibly corrected by means of lens, orthoptic exercises, and visual rehabilitation. Such a practical approach may help to ameliorate motor autonomy, reading ability, and may also reduce the risk of falls, with a positive impact in daily living activities.

CORRELATIONS between Functional and Structural Tests Measured by Spectral Domain Optical Coherence Tomography in Severe Glaucoma

Purpose: To evaluate the relationship between visual acuity, visual field and spectral domain optical coherence tomography (OCT) parameters, including retinal nerve fiber layer (RNFL), ganglion cell-internal plexiform layer (GC-IPL) thicknesses, and optic nerve head parameters in patients with severe glaucoma. Material and Methods: Patients with the diagnosis of severe glaucoma were recruited from the data gathered at our glaucoma department. A detailed ophthalmic examination was performed using the Standard Automated Perimetry (the 30-2 SITA standard program was used for VF testing). Cirrus EDI-OCT was used for peripapillary RNFL and GC-IPL thickness measurements. Optic nerve head parameters, including mean cup-to-disc (c/d) ratio, rim area, vertical c/d ratio, cup volume, were also measured by spectral domain OCT. Correlations between these structural parameters and functional parameters (visual acuity, VF parameters) were investigated. Results: Forty-one eyes of 34 patients with severe glaucoma were enrolled in this study. Correlations between BCVA and mean GC-IPL thickness (p = .03), superior GC-IPL thickness (p = .03), inferonasal GC-IPL thickness (p = .01), superonasal GC-IPL thickness (p = .01), superotemporal GC-IPL thickness (p = .04), and rim area (p = .00) were found to be positive statistically significant. There was also a positive statistically significant correlation between MD and inferotemporal GC-IPL thickness (p = .03). Negative statistically significant correlations were found between BCVA and mean c/d ratio (p = .00), vertical c/d ratio (p = .02) and cup volume (p = .00). Discussion: Mean, superior, inferonasal, superonasal, and superotemporal GC-IPL thicknesses and mean c/d ratio, vertical c/d ratio and cup volume were found to be correlated with BCVA in patients with severe glaucoma.

Comparison study of OCT, HRT and VF findings among normal controls and patients with pseudoexfoliation, with or without increased IOP

PURPOSE

To compare and evaluate optic nerve head (ONH) and retinal nerve fiber layer (RNFL) measurements obtained with the optical coherence tomography (OCT) and the Heidelberg retina tomography (HRT) to visual field (VF) parameters in normal and in patients with pseudoexfoliation with or without increased intraocular pressure (IOP).

METHODS

A total of 96 subjects were included in our study aged between 65 years and 78 years. The normal group consisted of 28 subjects (14 men and 14 women). Out of the total number of patients, 68 patients who showed pseudoexfoliation (21 men and 47 women) were divided into two groups. Of these, the first group had pseudoexfoliation with increased IOP and the second group showed deposits of pseudoexfoliative material without an increase in IOP. The normal controls were randomly chosen and restricted to those without any glaucomatous optic disc damages, VF defects, and an IOP <15 mmHg. All subjects were prospectively included for repeated measurements of IOP, OCT, HRT, and VFs during the same visit by the same examiner and all measurements were repeated every 3 months.

RESULTS

Mean RNFL thickness measured by OCT was larger in the normal controls than in the other two groups (98.04 μm (first group) vs 75.42 μm and 97.02 μm (second group), P<0.05). Four-quadrant RNFL thickness measurements were significantly different between the normal and the group 1 (P<0.05) but not with the group 2 (P>0.05). Rim area had a mean difference of -0.44, whereas cup-to-disc ratio (C/D) showed a mean difference of 0.31, thus being significantly different between the normal and the two groups (all P<0.05). The median of the mean deviation parameter of VFs was -0.28 for the normal vs -0.32 and -0.18 for the other two groups, whereas pattern standard deviation median difference was 0.89 for the normal and 1.32 and 1.20 for the other two groups, respectively (P<0.05).

CONCLUSION

Both OCT and HRT showed early ONH and RNFL changes in their parameters and did not correlate with the normal findings of the automated perimetry.

Comparison of peripapillary retinal nerve fiber layer loss and visual outcome in fellow eyes following sequential bilateral non-arteritic anterior ischemic optic neuropathy

AIM

To report on the correlation of structural damage to the axons of the optic nerve and visual outcome following bilateral non-arteritic anterior ischemic optic neuropathy.

METHODS

A retrospective review of the medical records of 25 patients with bilateral sequential non-arteritic anterior ischemic optic neuropathy was performed. Outcome measures were peripapillary retinal nerve fiber layer thickness measured with the Stratus optical coherence tomography scanner, visual acuity and visual field loss.

RESULTS

Median peripapillary retinal nerve fiber layer (RNFL) thickness, mean deviation (MD) of visual field, and visual acuity of initially involved NAION eyes (54.00 µm, -17.77 decibels (dB), 0.4, respectively) were comparable to the same parameters measured following development of second NAION event in the other eye (53.70 µm, p = 0.740; -16.83 dB, p = 0.692; 0.4, p = 0.942, respectively). In patients with bilateral NAION, there was a significant correlation of peripapillary RNFL thickness (r = 0.583, p = 0.002) and MD of the visual field (r = 0.457, p = 0.042) for the pairs of affected eyes, whereas a poor correlation was found in visual acuity of these eyes (r = 0.279, p = 0.176). Peripapillary RNFL thickness following NAION was positively correlated with MD of visual field (r = 0.312, p = 0.043) and negatively correlated with logMAR visual acuity (r = -0.365, p = 0.009).

CONCLUSION

In patients who experience bilateral NAION, the magnitude of RNFL loss is similar in each eye. There is a greater similarity in visual field loss than in visual acuity between the two affected eyes with NAION of the same individual.

Changes in retinal nerve fiber layer and optic disc algorithms by optical coherence tomography in glaucomatous Arab subjects

Purpose

To assess the difference in retinal nerve fiber layer (RNFL) and optic disc algorithms between glaucomatous and normal Arab subjects using optical coherence tomography (OCT).

Methods

RNFL thickness and optic disc parameters were obtained in 65 patients aged 50.1 ± 7.7 years. Percentage differences in all parameters were calculated and analyzed between groups.

Results

The mean RNFL thickness around the disc and at all quadrants was significantly thinner in glaucomatous eyes than in normal eyes (P < 0.01). The greatest decrease in RNFL thickness was observed at the inferior (39.5%) and superior (39.3%) quadrants and at 1 o’clock (43%) and 5 o’clock (40%) hour sectors. Significant differences were observed between glaucomatous and control eyes in all disc parameters (P < 0.005) assessed. The disc area, cup area, mean cup/disc ratio, and vertical and horizontal cup/disc ratios were significantly larger (P < 0.01), whereas the vertical integrated rim area, horizontal integrated rim width, and rim area were significantly smaller (P < 0.001) in glaucomatous eyes than in normal eyes.

Conclusion

Stratus OCT is still a valuable tool in the diagnosis of early glaucoma changes and, as such, its use should be encouraged in glaucoma clinics in Saudi Arabia. The best OCT parameters for detecting early glaucoma change were RNFL thickness in the inferior, superior, and 1 o’clock hour sector; the cup area; and the vertical integrated rim area of the optic disc.