Changes of visual field and optic nerve fiber layer in patients with OSAS

[Primary open angle glaucoma and sleep apnea syndrome: A review of the literature]

The relationship between glaucoma and Obstructive Sleep Apnea Syndrome (OSAS) has long been discussed, with conflicting study findings. OSAS appears in the most recent studies to be more of an aggravating factor than an independent risk factor for glaucoma. Patients with OSAS may develop a more rapid progression of primary open-angle glaucoma (POAG). OSAS may damage the optic nerve not only by increasing the intraocular pressure (IOP) but also by altering the blood supply to the optic nerve as shown by more recent work with OCT-Angiography. Although the systemic benefits of Continuous Positive Airway Pressure (CPAP) have been demonstrated, few studies have evaluated its effect on the optic nerve. CPAP might act on glaucomatous neuropathy by improving the blood supply to the optic nerve. The study of this mechanism of action might provide new insights into the relationship between OSAS and glaucoma.

Obstructive sleep apnoea and glaucoma: a systematic review and meta-analysis

INTRODUCTION

Obstructive sleep apnoea (OSA) has been thought to be associated with glaucoma, however there are many conflicting studies on this topic. With many new studies having been published since the previous meta-analysis, we believe it is important to clarify this association. Hence, in this study we meta-analyse the recent literature regarding the association between OSA and glaucoma.

METHODS

Pubmed, Embase, Scopus and Cochrane Library were searched from inception till the 28th February 2022 for observational as well as cross-sectional studies examining the association between OSA and glaucoma. Two reviewers selected studies, extracted data, graded the quality of included non-randomized studies using the Newcastle-Ottawa scale. The overall quality of evidence was assessed using GRADE. Random-effects models were used to meta-analyse the maximally covariate- adjusted associations.

RESULTS

48 studies were included in our systematic review, with 46 suitable for meta-analysis. Total study population was 4,566,984 patients. OSA was associated with a higher risk of glaucoma (OR 3.66, 95% CI 1.70 to 7.90, I2 = 98%, p < 0.01). After adjustment for various important confounders including age, gender and patient comorbidities such as hyperlipidaemia, hypertension, cardiovascular diseases and diabetes, patients with OSA had up to 40% higher odds of glaucoma. Substantial heterogeneity was eliminated through subgroup and sensitivity analyses after consideration of glaucoma subtype, OSA severity and adjustment for confounders.

CONCLUSIONS

In this meta-analysis, OSA was associated with higher risk of glaucoma, as well as more severe ocular findings characteristic of the glaucomatous disease process. We suggest more clinical studies looking into the effects of OSA treatment on the progression of glaucoma to help clinical decision making for patients.

Primary open-angle glaucoma in patients with obstructive sleep apnoea in a Colombian population: a cross-sectional study

OBJECTIVE

Determine the prevalence, functional and structural alterations of primary open-angle glaucoma (POAG) in patients with obstructive sleep apnoea (OSA).

DESIGN

Cross-sectional.

SETTING

Tertiary hospital associated with specialised center in ophthalmologic images in Bogota, Colombia.

PARTICIPANTS

150 patients, for a sample of 300 eyes, 64 women (42.7%) and 84 men (57.3%) between 40 and 91 years old with a mean age of 66.8 (±12.1) years.

INTERVENTIONS

Visual acuity, biomicroscopy, intraocular pressure, indirect gonioscopy and direct ophthalmoscopy. Patients classified as glaucoma suspects underwent automated perimetry (AP) and optical coherence tomography of the optic nerve OUTCOME MEASURE: The primary outcomes are the determination of prevalence of glaucoma suspects and POAG in patients with OSA. Secondary outcomes are the description of functional and structural alterations in computerised exams of patients with OSA.

RESULTS

The prevalence of glaucoma suspect was 12.6%, and for POAG was 17.3%. No alterations in the appearance of the optic nerve was seen in 74.6%, focal or diffuse thinning of the neuroretinal rim (16.6%) was the most frequently finding, followed by asymmetry of the disc>0.2 mm (8.6%) (p=0.005). In the AP, 41% showed arcuate, nasal step and paracentral focal defects. The mean retinal nerve fiber layer (RNFL) was normal (>80 µM) in 74% of the mild OSA group, 93.8% of the moderate group and 17.1% of the severe group. Similarly, normal (P5-90) ganglion cell complex (GCC) in 60%, 68% and 75%, respectively. Abnormal results in the mean RNFL was seen in 25.9%, 6.3% and 23.4% of the mild, moderate and severe groups, respectively. In the GCC, 39.7%, 33.3% and 25% of the patients in the aforementioned groups.

CONCLUSION

It was possible to determine the relationship between structural changes in the optic nerve and the severity of OSA. No relationship with any of the other studied variables was identified.

Differential effects of obstructive sleep apnea on the corneal subbasal nerve plexus and retinal nerve fiber layer

Purpose

Obstructive sleep apnea (OSA) is an established independent risk factor for peripheral neuropathy. Macro and microvascular changes have been documented in OSA, including high levels of potent vasoconstrictors. In diabetes, vasoconstriction has been identified as an underlying risk factor for corneal neuropathy. This study sought to establish a potential relationship between OSA and corneal nerve morphology and sensitivity, and to determine whether changes in corneal nerves may be reflective of OSA severity.

Design

Single center cross-sectional study.

Methods

Sixty-seven patients were stratified into two groups: those with OSA and healthy controls. Groups were matched for age, sex, race, smoking, and dry eye status. Outcome measures included serologies, a dilated fundus exam, dry eye testing, anthropometric parameters, corneal sensitivity, subbasal nerve plexus morphology, retinal nerve fiber layer (RNFL) thickness, and the use of questionnaires to assess symptoms of dry eye disease, risk of OSA, and continuous positive airway pressure (CPAP) compliance.

Results

No significant differences were observed in corneal nerve morphology, sensitivity, or the number of dendritic cells. In the OSA test group, RNFL thinning was noted in the superior and inferior regions of the optic disc and peripapillary region. A greater proportion of participants in the OSA group required a subsequent evaluation for glaucoma than in the control. In those with OSA, an increase in the apnea hypopnea index was associated with an increase in optic nerve cupping.

Conclusions

OSA does not exert a robust effect on corneal nerves. OSA is however, associated with thinning of the RNFL. Participants with glaucomatous optic nerve changes and risk factors for OSA should be examined as uncontrolled OSA may exacerbate glaucoma progression.

Sleep, cerebrospinal fluid, and the glymphatic system: A systematic review

Current theories of the glymphatic system (GS) hypothesize that it relies on cerebrospinal fluid (CSF) circulation to disseminate growth factors and remove metabolic waste from the brain with increased CSF production and circulation during sleep; thereby, linking sleep disturbance with elements of CSF circulation and GS exchange. However, our growing knowledge of the relations between sleep, CSF, and the GS are plagued by variability in sleep and CSF measures across a wide array of pathologies. Hence, this review aims to summarize the dynamic relationships between sleep, CSF-, and GS-related features in samples of typically developing individuals and those with autoimmune/inflammatory, neurodegenerative, neurodevelopmental, sleep-related, neurotraumatic, neuropsychiatric, and skull atypicalities. One hundred and ninety articles (total n = 19,129 participants) were identified and reviewed for pathology, CSF circulation and related metrics, GS function, and sleep. Numerous associations were documented between sleep problems and CSF metabolite concentrations (e.g., amyloid-beta, orexin, tau proteins) and increased CSF volumes or pressure. However, these relations were not universal, with marked differences across pathologies. It is clear that elements of CSF circulation/composition and GS exchange represent pathways influenced by sleep; however, carefully designed studies and advances in GS measurement are needed to delineate the nuanced relationships.

Ganglion cell layer thickening in patients suffering from Obstructive Sleep Apnea-Hypopnea syndrome with long Mean Apnea-Hypopnea Duration during sleep

PURPOSE

To study the effects of mean apnea-hypopnea duration (MAD), a useful indicator of blood oxygenation, on peripapillary retinal nerve fiber layer (RNFL), macular ganglion cell to inner plexiform layer (GC-IPL) and macular retinal thickness in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS).

METHODS

Sixty-five patients recently diagnosed with OSAHS and 35 healthy individuals were enrolled in this cross-sectional study. OSAHS patients were divided according to their MAD values into group 1 with 16 participants (MAD:10-15.5 s), group 2 with 17 participants (MAD:15.5-19 s), group 3 with 17 participants (MAD:19-30 s) and group 4 with 15 participants (MAD > 30 s). The average and sectorial values of RNFL, GC-IPL and retinal thickness were measured by SS-OCT (DRI OCT Triton, Topcon). Intraocular pressure was recorded by Goldmann Applanation and Pascal Dynamic Contour Tonometer (DCT-IOP).

RESULTS

The average RNFL and retinal thickness values were higher in group 4, but did not reach statistical significance. With the exception of the central 1 mm at the fovea, GC-IPL was always thickened in group 4, and significant differences were evident when its average value was compared with group 2 (p = 0.03), its superior and inferior-nasal values were compared with group 2 (p = 0.02, p = 0.006, respectively) and group 3 (p = 0.01, p = 0.02, respectively), its superior-temporal value was compared with group 3 (p = 0.003) and the control group (p = 0.03), and its superior-nasal value was compared with group 2 (p = 0.03), group 3 (p = 0.001) and the control group (p = 0.03). DCT-IOP was significantly positively correlated with the duration of sleep in which oxygen saturation (SaO₂ ) was decreased under 90% (r = 0.359, p = 0.01).

CONCLUSION

We report a novel observation of GC-IPL thickening in OSAHS patients experiencing long MAD, a parameter which incorporates the severity of breathing events during sleep. Higher DCT-IOP was noted with advancing hypoxemia.

Obstructive sleep apnea as a risk factor for primary open angle glaucoma and ocular hypertension in a monocentric pilot study

Background

Both glaucoma and obstructive sleep apnea (OSA) are widespread diseases. OSA may presumably partly cause or worsen glaucoma, although the etiopathogenesis is unclear. Here we analyze for the first time the possible association between different glaucoma phenotypes and OSA.

Methods

110 patients (47 females, 63 males; median age 64.3 years, median BMI 26.62 kg/m²) with suspected glaucoma and without any prior diagnosis of OSA were prospectively studied by one-night home sleep apnea testing (HSAT), 101 of the patients were analyzed. HSAT parameters, like apnea hypopnea index (AHI) and oxygen desaturation index as well as opthalmological parameters like intraocular pressure (IOP) and mean defect depth (MD) were collected. Moreover, HSAT results were compared across four phenotypic groups: primary open angle glaucoma (POAG), low-tension-glaucoma (LTG), ocular hypertension (OH), and controls.

Results

There was no strong correlation between IOP or MD and AHI. BMI, age and gender did not differ between groups. Significant differences between POAG and LTG were found for all HSAT parameters. The AHI showed the most prominent group difference (Wilcoxon-Kruskal-Wallis rank sum test was highly significant with chi² = 22, df = 3 p < 0.0001) with severely lower event rates in the LTG (9.45/h) compared to POAG (22.7/h) and controls (21.9/h; p < 0.0001 and 0.02, respectively). Highly significant differences were found between the four groups regarding AHI (Chi² = 22, df = 3, p < 0.0001) with significantly lower events per hour in the LTG compared to POAG (Hodges-Lehmann = − 13.8, 95% CI (− 18.6 – − 8.8; p < 0.0001) and to controls (Hodges-Lehmann = 12.1, 95% CI -19.9 – − 2.4; p < 0.02). Severe and moderate OSA was more prevalent in POAG (69.8%) and OH (33.3%) than in LTG (9%). The effect of the glaucoma phenotype on the AHI was more prominent in females (p = 0.0006) than in males (p = 0.011).

Conclusion

Although physical endpoints, such as MD and IOP, do not correlate with AHI, there was a strong correlation between the POAG and OH clinical glaucoma phenotypes and the AHI. Further studies should investigate the necessity to test routine screening for OSA by HSAT in patients with diagnosed POAG and OH. Besides, some characteristics of LTG differed widely from other glaucoma types and controls. LTG patients had a significantly lower rate of OSA compared to other glaucoma types and even controls. This might be due to a different pathogenesis of LTG.

Trial registration

Retrospectively registered at DRKS (nr. S00021201) on April 9th 2020.

Evaluation of effects of positive airway pressure treatment on retinal fiber thickness and visual pathways using optic coherence tomography and visual evoked potentials in the patients with severe obstructive sleep apnea syndrome

INTRODUCTION

Hypoxia during sleep in obstructive sleep apnea syndrome (OSAS) increases intracranial pressure, decreases cerebral perfusion pressure, and alters vascular supply to the optic nerve. Pattern visual evoked potential (pVEP) has revealed that it causes alterations in the optic nerve, and optic coherence tomography has shown that it causes alterations in the retinal and macular layers.

OBJECTIVES

To detect and compare possible alterations in macula and peripapillary retinal nerve fiber thickness (pRNFL) using OCT and in the optic nerve pathways using pVEP before and after positive airway pressure (PAP) in the patients with severe OSAS.

MATERIALS AND METHODS

Thirty patients who were diagnosed as having severe OSAS in the neurology-sleep outpatient clinic and 30 healthy control subjects were included in the study. Ophthalmic examinations were performed prior to (month 0) and after (month 6) PAP treatment, and pVEP (peak time [PT] and amplitude) and OCT parameters (peripapillary retinal-macular layers) were compared.

RESULTS

In the comparison between the severe OSAS (before treatment) and control groups, thinning was found in pRNFL (average, nasal, inferior) and in the macular layers (external and internal superior quadrants) (p < 0.05). pVEP investigation revealed increased PT in P100 and N145 waves and decreased amplitude of N75-P100 waves. In the comparisons before and after PAP treatment, a decrease in PT of N75 and P100 waves and increase in N75-P100 amplitudes were found. In the pRNFL, significant thickening was found in the layers with thinning before treatment, whereas no significant thickening was found in macular layers, except for the fovea.

DISCUSSION

It was shown that PAP treatment in patients with severe OSAS prevents hypoxia without causing alterations in intraocular pressure and thus reduces inflammation and causes thickening in the pRNFL and macular layers.

Contributions of the Melanopsin-Expressing Ganglion Cells, Cones, and Rods to the Pupillary Light Response in Obstructive Sleep Apnea

Purpose

To investigate the impact of obstructive sleep apnea (OSA) on the contribution of inner and outer retinal photoreceptors to the pupillary light response (PLR).

Methods

Ninety-three eyes from 27 patients with OSA and 25 healthy controls were tested. OSA severity was graded according to the apnea-hypopnea index. PLR was measured monocularly with an eye tracker in a Ganzfeld in response to 1-second blue (470 nm) and red (640 nm) flashes at -3, -2, -1, 0, 1, 2, and 2.4 log cd/m2. Peak pupil constriction amplitude, peak latency, and the postillumination pupil response were measured. The Cambridge Colour Test, standard automatic perimetry, spectral domain optical coherence tomography, polysomnography, and the Pittsburgh Sleep Quality Index were used.

Results

OSA patients have a significantly decreased peak pupil constriction amplitude for blue stimuli at -3, -2, -1, 1 log cd/m2 and at all red flash luminances (P < 0.050), revealing reduction of outer retina contributions to PLR. OSA patients showed reduced peak latency for blue (-2, 0, 2, 2.4 log cd/m2) and red stimuli (-2, 0 log cd/m2; P < 0.040). No significant difference was found in the melanopsin-mediated PLR.

Conclusions

This study is the first to evaluate the inner and outer retinal contributions to PLR in OSA patients. The results showed that the outer retinal photoreceptor contributions to PLR were affected in moderate and severe OSA patients. In contrast, the inner retina contributions to PLR are preserved.

Investigation of the Presence of Glaucoma in Patients with Obstructive Sleep Apnea Syndrome Using and Not Using Continuous Positive Airway Pressure Treatment

Objectives:

To evaluate the frequency of glaucoma in patients with obstructive sleep apnea syndrome (OSAS) using and not using continuous positive airway pressure treatment.

Materials and Methods:

This prospective study included 59 patients diagnosed with OSAS based on the Apnea-Hypopnea Index (AHI). OSAS patients were divided into 3 groups according to their AHI scores: 5-15 was considered mild (19 patients), 16-30 was considered moderate (16 patients), and >30 (24 patients) was considered severe. Twenty-eight (47.5%) of the OSAS patients had been using continuous positive airway pressure treatment. The control group included 19 healthy subjects. Retinal nerve fiber layer and ganglion cell complex (GCC) thickness analyses were performed.

Results:

Average GCC thickness in left eyes was significantly lower in the mild OSAS group than in the control group (p=0.013). The GCC was significantly thinner in the inferior and inferonasal sectors of both eyes in the mild OSAS group compared to the control group (p=0.029, p=0.022, p=0.037, and p=0.019 respectively). Minimum GCC thickness in the left eyes of all OSAS groups was significantly lower than in the control group (p<0.05).

Conclusion:

In OSAS patients, there may be changes in retinal nerve fiber layer and ganglion cell complex thickness before alterations in the visual field emerge.

Prevalence and Predictors of Ocular Complications in Obstructive Sleep Apnea Patients: A Cross-sectional Case-control Study

Purpose:

This study sought to identify the magnitude and the possible risk factors of ocular complications in patients with Obstructive Sleep Apnea (OSA).

Methods:

A hospital-based cross-sectional study with a nested case-control design was conducted. Qualifying study subjects were patients who had been diagnosed with moderate to severe OSA (AHI index of ≥ 5, n=80), and control subjects (n=20) who had an AHI index of ≤ 5 (“normal”). Study participants were recruited from Mansoura University Hospital’s Sleep Disorders Clinic in Mansoura, Egypt.Selected subjects were assessed for ocular complications at Mansoura Univerity Hospital Ophthalmic Center, (Mansoura), Egypt. An ophthalmic history was recorded, and opthalmic testing was carried out. The testing included unaided visual acuity measurement, refraction, best-corrected visual acuity measurement, slit lamp bio-microscopic evaluation of the anterior segment and anterior segment photography, dilated fundus examination, intraocular pressure measurement, fundus photo, and fluorescein angiography, and visual field assessment. Various tests of OSA symptoms were also monitored, including the AHI, lowest oxygen concentrations and desaturation index plus the overall severity index. .

Results:

It was found that OSA patients n=28 (35%), n=24 (30%), n=4 (5%) had senile cataract, normal tension glaucoma, and retinal ischemia, respectively, with an overall prevalence of 45%. Additionally, the OSA group had seven times greater risk (OR=7.36, 95%CI: 1.6-33.86) of vision-threatening disorders compared to the controls. OSA patients were observed to be at a greater risk of senile cataract 28 (35%), normal tension glaucoma 24 (30%), retinal ischemia 4 (5%) and conjunctival hyperemia and dry eye (OR=3.77, 95%CI: 1.02-13.95, OR=4.36, 95%CI: 1.26-17.08). Also, multivariate logistic regression analysis testing showed that the lowest oxygen saturation index was the only significant predictor negatively associated with vision-threatening disorders (OR=0.84, 95%CI: 0.75-0.93).

Conclusion:

The risk of vision-threatening and non-threatening ocular disorders is higher among OSA cases. The lowest oxygen saturation index was the only significant predictor of vision-threatening disorders. These findings support the recommendation that a full ophthalmic examination should be carried out on patients with confirmed OSA.

Bone Metabolic Markers in Patients with Obstructive Sleep Apnea Syndrome

Background:

Obstructive sleep apnea syndrome (OSAS) is prevalent in obesity and is associated with many metabolic abnormalities. The relationship between OSAS and bone metabolism is still unclear. The aim of this study was to investigate the relationship between the severity of OSAS and bone metabolic markers.

Methods:

A total of 119 obese males were enrolled in this study in spring months from 2015 to 2017. All candidates underwent polysomnography, and their bone mineral density (BMD) and the serum levels of total procollagen type 1 N-terminal propeptide (t-P1NP), N-terminal midfragment of osteocalcin (N-MID), β-C-terminal telopeptide of type 1 collagen (β-CTX), vitamin D (VD), and parathyroid hormone (PTH) were measured. The analysis of variance and Pearson correlation analysis were performed for data analyses.

Results:

No significant differences in the mean values of BMD were observed among the obesity, mild-to-moderate OSAS, and severe OSAS groups; and the serum levels of t-P1NP and β-CTX in the severe OSAS group were significantly higher than those in the obesity group (48.42 ± 23.78 ng/ml vs. 31.98 ± 9.85 ng/ml, P < 0.001; 0.53 ± 0.24 ng/ml vs. 0.41 ± 0.13 ng/ml, P = 0.011, respectively). The serum level of VD in the obesity group was significantly higher than those in the mild-to-moderate and severe OSAS groups (both P < 0.001), and decreased as the severity of OSAS increased (P < 0.001). The serum level of PTH in the severey and mild-to-moderate OSAS groups (both P < 0.001). The results of correlation analysis indicated that the level of apnea-hypopnea index (AHI) was correlated with the levels of t-P1NP (r = 0.396, P < 0.001), VD (r = –0.404, P < 0.001), and PTH (r = 0.400, P < 0.001), whereas the level of minimum O₂ saturation (SaO₂ min) was correlated with the levels of VD (r = 0.258, P = 0.016) and PTH (r = –0.376, P < 0.001).

Conclusions:

The levels of bone resorption and formation markers in patients with severe OSAS were significantly increased compared to obese men, and the severity of OSAS was correlated with the serum levels of t-P1NP, VD, and PTH.

Aberrant Interhemispheric Connectivity in Obstructive Sleep Apnea-Hypopnea Syndrome

Objective

To determine the changes in interhemispheric functional coordination in patients with obstructive sleep apnea–hypopnea syndrome (OSAHS) relative to controls, using a recently introduced method of analysis: voxel-mirrored homotopic connectivity (VMHC).

Methods

Twenty-nine patients with OSAHS and twenty-six normal sex-, age-, and education-matched controls were recruited and resting-state functional magnetic resonance imaging data were obtained. We employed VMHC to analyze the interhemispheric functional connectivity differences between groups. The z-values of alterations in VMHC in brain region were correlated with clinical characteristics.

Results

Compared with controls, patients with OSAHS had significantly higher scores for body mass index (t = 5.749, P < 0.001), apnea–hypopnea index (AHI; t = 7.706, P < 0.001), oxygen desaturation index (t = 6.041, P < 0.001), and Epworth sleepiness scale (t = 3.711, P < 0.001), but significantly lower scores on the Rey–Osterrieth complex figure test-immediate recall (t = −3.727, P < 0.05). On the same basis, the VMHC showed significant increases in bilateral calcarine cortex and precuneus. Moreover, significant, positive correlations were found in only these areas between the AHI and the VMHC change coefficients (r = 0.399, P = 0.032; r = 0.378, P = 0.043).

Conclusion

We found a memory defect in patients with OSAHS. The correlation between the abnormal VMHC and the AHI in patients with OSAHS suggested that AHI might be a key factor in cognitive dysfunction, which might offer new insights into the neural pathophysiology underlying OSAHS-related cognitive deficits.

Visual field defects and retinal nerve fiber imaging in patients with obstructive sleep apnea syndrome and in healthy controls

Background

To assess the retinal sensitivity in obstructive sleep apnea hypopnea syndrome (OSAHS) patients evaluated with standard automated perimetry (SAP). And to correlate the functional SAP results with structural parameters obtained with optical coherence tomography (OCT).

Methods

This prospective, observational, case-control study consisted of 63 eyes of 63 OSAHS patients (mean age 51.7 ± 12.7 years, best corrected visual acuity ≥20/25, refractive error less than three spherical or two cylindrical diopters, and intraocular pressure < 21 mmHg) who were enrolled and compared with 38 eyes of 38 age-matched controls. Peripapillary retinal nerve fiber layer (RNFL) thickness was measured by Stratus OCT and SAP sensitivities and indices were explored with Humphrey Field Analyzer perimeter. Correlations between functional and structural parameters were calculated, as well as the relationship between ophthalmologic and systemic indices in OSAHS patients.

Results

OSAHS patients showed a significant reduction of the sensitivity for superior visual field division (p = 0.034, t-student test). When dividing the OSAHS group in accordance with the severity of the disease, nasal peripapillary RNFL thickness was significantly lower in severe OSAHS than that in controls and mild-moderate cases (p = 0.031 and p = 0.016 respectively, Mann-Whitney U test). There were no differences between groups for SAP parameters.

We found no correlation between structural and functional variables. The central visual field sensitivity of the SAP revealed a poor Pearson correlation with the apnea-hipopnea index (0.284, p = 0.024).

Conclusions

Retinal sensitivity show minor differences between healthy subjects and OSAHS. Functional deterioration in OSAHS patients is not easy to demonstrate with visual field examination.

Retinal nerve fiber layer thickness changes in obstructive sleep apnea syndrome: a systematic review and Meta-analysis

AIM

To evaluate the retinal nerve fiber layer (RNFL) thickness changes in patients with obstructive sleep apnoea syndrome (OSAS), and detect possible prevalence of glaucoma in this population.

METHODS

Comprehensive studies were conducted on the Cochrane Library, PubMed and Embase through March, 2015. Only studies that fit the selection criteria about RNFL and OSAS would be included. For the measures, we calculated the 95% confidence interval (CI) and weighted mean differences (WMD). The systematic review and Meta-analysis was performed by RevMan 5.2 software.

RESULTS

Nine case-control studies were analyzed containing a total of 1086 cases and 580 controls. Average RNFL thickness in OSAS was reduced significantly compared with healthy controls in random effects model (WMD=-2.56, 95% CI: -4.82 to -0.31, P =0.003, I²=57%). A significant RNFL thickness reduction were found between the two groups in inferior quadrant (WMD=-3.11, 95% CI: -5.53 to -0.69, P=0.01), superior quadrant (WMD=-2.37, 95%CI: -4.7 to 0.04, P=0.05). In nasal quadrant (WMD=-2.54, 95% CI: -6.53 to 1.45, P=0.21) and temporal quadrant (WMD=-1.26, 95% CI: -2.19 to 0.47, P=0.15) there was no difference of RNFL thickness between the two groups.

CONCLUSION

The results show that RNFL thickness is lower in patients with moderate or severe OSAS than in normal subjects or patients with mild OSAS according to the nine homogeneity studies.

Changes of Retinal Nerve Fiber Layer Thickness in Obstructive Sleep Apnea Syndrome: A Systematic Review and Meta-analysis

PURPOSE

Many studies have assessed the changes of retinal nerve fiber layer (RNFL) thickness in patients with obstructive sleep apnea syndrome (OSAS), but the results were inconsistent. Therefore, a meta-analysis was performed to evaluate the RNFL changes in OSAS measured in vivo.

METHODS

Pertinent studies were identified by a comprehensive search of PubMed, Embase, Web of science, Cochrane library, Scopus, and Chinese biomedical disc databases from inception to August 2016. A fixed effects model was used to pool the weighted mean difference (WMD) and 95% confidence interval (CI) between OSAS group and control group.

RESULTS

Seventeen studies were included in the final analysis, with 12 for descriptive analysis and 5 for meta-analysis, involving a total of 1757 eyes (1106 in the OSAS group and 651 in the control group). The RNFL in OSAS was significantly lower than control group, with pooled WMD -3.53 (95%CI: -4.80 to -2.26, P < 0.001) for average RNFL, -3.69 (95%CI:-5.49 to -1.89 P < 0.001) for superior RNFL, -4.66 (95%CI: -6.92 to -2.39, P < 0.001) for inferior RNFL, -3.15 (95%CI:-5.19 to -1.10, P = 0.003) for nasal RNFL, and -2.45 (95%CI: -4.59 to -0.31, P = 0.025) for temporal RNFL. Along with severities of OSAS, a trend of more profound reduction of average RNFL was observed in advanced OSAS, with WMD of average RNFL thickness -1.75 (95%CI:-4.47 to -0.98, P = 0.209) for mild OSAS, -3.54 (95%CI:-6.33 to -0.73, P = 0.013) for moderate OSAS, and -7.17 (95%CI:-10.00 to -4.34, P < 0.001) for severe OSAS. The majority of studies in the descriptive review demonstrated similar findings.

CONCLUSION

The OSAS was associated with a reduced RNFL in all quadrants compared to controls. Evaluation of RNFL may serve as a tool for grading severities of OSAS. Considering the limited evidence, the conclusions should be interpreted cautiously.

Decreased retinal nerve fiber layer thickness in patients with obstructive sleep apnea syndrome: A meta-analysis

OBJECTIVE

To investigate the changes of retinal nerve fiber layer (RNFL) thickness in obstructive sleep apnea syndrome (OSAS) patients.

METHODS

Relevant studies were selected from 3 major literature databases (PubMed, Cochrane Library, and EMBASE) without language restriction. Main inclusion criteria is that a case-control study in which RNFL thickness was measured by a commercial available optical coherence tomography (OCT) in OSAS patients. Meta-analysis was performed using STATA 12.0 software. Efficacy estimates were evaluated by weighted mean difference with corresponding 95% confidence intervals (CIs). Primary outcome evaluations were: the average changes of RNFL thickness in total OSAS patients, subgroup analysis of RNFL thickness changes in patients of different OSAS stages, and subgroup analysis of 4-quadrant RNFL thickness changes in total OSAS patients.

RESULTS

Of the initial 327 literatures, 8 case-control studies with 763 eyes of OSA patients and 474 eyes of healthy controls were included (NOS scores ≥6). For the people of total OSAS, there had an average 2.92 μm decreased RNFL thickness compared with controls (95% CI: -4.61 to -1.24, P = 0.001). For subgroup analysis of OSAS in different stages, the average changes of RNFL thickness in mild, moderate, severe, and moderate to severe OSAS were 2.05 (95% CI: -4.40 to 0.30, P = 0.088), 2.32 (95% CI: -5.04 to 0.40, P = 0.094), 4.21 (95% CI: -8.36 to -0.06, P = 0.047), and 4.02 (95% CI: -7.65 to -0.40, P = 0.03), respectively. For subgroup analysis of 4-quadrant, the average changes of RNFL thickness in Superior, Nasal, Inferior, and Temporal quadrant were 2.43 (95% CI: -4.28 to -0.57, P = 0.01), 1.41 (95% CI: -3.33 to 0.51, P = 0.151), 3.75 (95% CI: -6.92 to -0.59, P = 0.02), and 0.98 (95% CI: -2.49 to 0.53, P = 0.203), respectively.

CONCLUSION

Our study suggests that RNFL thickness in OSAS patients is much thinner than healthy population, especially in superior and inferior quadrant. The impact of OSAS disease on RNFL and visual function should be taken seriously in the further study.

Changes in Retinal Nerve Fiber Layer Thickness in Obstructive Sleep Apnea/Hypopnea Syndrome: A Meta-Analysis

PURPOSE

To evaluate and compare changes in retinal nerve fiber layer (RNFL) thickness in patients with obstructive sleep apnea/hypopnea syndrome (OSAHS).

METHODS

The Cochrane Library, Medline, and Embase were screened using our key words. Results were carefully reviewed to ensure that the included studies met the inclusion/exclusion criteria, and the quality of the studies was assessed using the Newcastle-Ottawa Scale. All included studies categorized patients with OSAHS into 3 groups (mild, moderate, and severe), and measured average and 4-quadrant (temporal, superior, nasal, and inferior) RNFL thickness. All studies included a healthy control group. The weighted mean differences and 95% confidence intervals were calculated for the continuous outcomes.

RESULTS

Ten case-control studies were included in the meta-analysis, consisting of a total of 811 OSAHS group and 868 healthy eyes. A meta-analysis of the data showed that the average RNFL thicknesses in the mild, moderate, and severe OSAHS groups were significantly decreased compared to healthy controls. Additionally, RNFL thickness was significantly reduced in all but the temporal quadrant in the moderate and severe OSAHS groups when compared to healthy controls.

CONCLUSIONS

On the basis of these results, we suggest that peripapillary RNFL thickness as measured by optical coherence tomography could be a useful tool to monitor and assess the severity of OSAHS in patients. Further studies are required in order to differentiate these RNFL changes from glaucomatous changes. This has not been properly examined in any of the studies we were able to identify.

Macular Retinal Ganglion Cell Layer Thickness Is Not Reduced in Patients with Obstructive Sleep Apnea

PURPOSE

To evaluate macular ganglion cell layer (GCL) and ganglion cell-inner plexiform layer (GCIPL) thicknesses in patients with obstructive sleep apnea (OSA) syndrome.

METHODS

73 OSA patients and 67 age-matched controls were consecutively and prospectively enrolled. All participants underwent at least one reliable standard automated perimetry (SAP) and were imaged with spectral-domain optical coherence tomography (OCT) using two different devices. The OCT parameters were compared between groups, and Pearson correlations between main indices of SAP and OCT parameters were calculated.

RESULTS

The pattern standard deviation of SAP was higher in the OSA group (p = 0.001). Mean GCIPL thickness was 82.99 ± 10.30 and 80.78 ± 12.15 µm in the control and OSA groups, respectively (p = 0.25), and GCL thickness was 44.93 ± 11.42 µm in the control group and 48.81 ± 10.85 µm in OSA individuals (p = 0.47). Pearson correlations between the GCIPL-GCL measurements and the main indices of SAP were not significant.

CONCLUSIONS

Neither GCIPL nor GCL thickness were reduced in OSA subjects compared with healthy individuals. Retinal sensitivity evaluated with SAP was however decreased in OSA patients.