Retinal nerve fibre layer thickness measurements by optical coherence tomography in patients with sleep apnoea syndrome

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.

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.

Combining Optical Coherence Tomography and Fundus Photography to Improve Glaucoma Screening

We aimed to evaluate the accuracy of glaucoma screening using fundus photography combined with optical coherence tomography and determine the agreement between ophthalmologists and ophthalmology residents. We used a comprehensive ophthalmologic examination dataset obtained from 503 cases (1006 eyes). Of the 1006 eyes, 132 had a confirmed glaucoma diagnosis. Overall, 24 doctors, comprising two groups (ophthalmologists and ophthalmology residents, 12 individuals/group), analyzed the data presented in three screening strategies as follows: (1) fundus photography alone, (2) fundus photography + optical coherence tomography, and (3) fundus photography + optical coherence tomography + comprehensive examination. We investigated the diagnostic accuracy (sensitivity and specificity). The respective sensitivity and specificity values for the diagnostic accuracy obtained by 24 doctors, 12 ophthalmologists, and 12 ophthalmology residents were as follows: (1) fundus photography: sensitivity, 55.4%, 55.4%, and 55.4%; specificity, 91.8%, 94.0%, and 89.6%; (2) fundus photography + OCT: sensitivity, 80.0%, 82.3%, and 77.8%; specificity, 91.7%, 92.9%, and 90.6%; and (3) fundus photography + OCT + comprehensive examination: sensitivity 78.4%, 79.8%, and 77.1%; specificity, 92.7%, 94.0%, and 91.3%. The diagnostic accuracy of glaucoma screening significantly increased with optical coherence tomography. Following its addition, ophthalmologists could more effectively improve the diagnostic accuracy than ophthalmology residents. Screening accuracy is improved when optical coherence tomography is added to fundus photography.

[Normal Tension Glaucoma]

Normal tension glaucoma (NTG) is a subvariant of primary open angle glaucoma (POAG) or a separate entity. NTG is defined as chronic open angle glaucoma without elevated intraocular pressure or normal intraocular pressure. Normal intraocular pressure is between 10 and 21 mmHg and is defined as two times the standard deviation of the mean intraocular pressure in the normal population. In addition to the absence of elevated intraocular pressure, all the classic symptoms of glaucoma are otherwise present. These include a conspicuous glaucomatous optic disc excavation, nerve fibre bundle defects, and corresponding visual field defects. Papillary rim haemorrhages are frequently found. The visual field defects in NDG are usually more central compared to POAG and are therefore described as more disturbing by the patient. The anterior chamber angle is open and there are no other changes suggestive of secondary glaucoma (pigment dispersion, pseudo-exfoliation). The exact pathophysiology of NDG is not well understood. Pathophysiologically, circulatory disturbances in the sense of arterial hypo- as well as hypertension may play an essential role or at least increase the susceptibility of the optic nerve to intraocular pressure fluctuations as well as blood pressure dips. Therefore, this requires not only a purely ophthalmologic but also interdisciplinary treatment of the patient with confirmed NDG. The primary goal of treatment is the reduction of intraocular pressure, which can stop the disease. This article gives an overview of epidemiology, aetiology, clinical findings and therapies.

Normaldruckglaukome

Das Normaldruckglaukom wird definiert wird als primär chronisches Offenwinkelglaukom, bei dem kein erhöhter Augeninnendruck vorliegt. Trotz normalem Augeninnendruck ist das primäre Ziel der Behandlung die Augeninnendrucksenkung, mit der es gelingen kann, die Erkrankung aufzuhalten. Dieser Artikel soll eine Übersicht über Epidemiologie, Ätiologie, Pathogenese, klinische Befunde sowie Therapien geben.

Assessment of the Effectiveness of Obstructive Sleep Apnea Treatment Using Optical Coherence Tomography to Evaluate Retinal Findings

Retinal findings may change in patients with obstructive sleep apnea syndrome (OSAS). The present study aims to evaluate several retinal findings, such as macula layer thickness, the peripapillary retinal nerve fiber layer, and the optic nerve head in patients with OSAS, using optical coherence tomography (OCT); it also aims to monitor the result of several types of treatment of OSAS with OCT. A prospective comparative study was designed. Patients were recruited at a Sleep Unit of a University Hospital and underwent comprehensive ophthalmological examinations. Following exclusion criteria, fifty-two patients with OSAS were finally included. Patients were examined by OCT twice: once before treatment, and again after six months of treatment. In mild–moderate patients, where retinal swelling had been demonstrated, retinal thicknesses decreased [fovea (p = 0.026), as did inner ring macula (p = 0.007), outer ring macula (p = 0.015), and macular volume (p = 0.015)]. In severe patients, where retinal atrophy had been observed, retinal thickness increased [fovea (p < 0.001)]. No statistically significant differences in efficacy between treatments were demonstrated. In conclusion, OCT can evaluate the retina in patients with OSAS and help to monitor results after treatment. In severe OSAS, retinal thickness increased six months after treatment.

Diurnal changes of retinal microvascular circulation and RNFL thickness measured by optical coherence tomography angiography in patients with obstructive sleep apnea-hypopnea

PURPOSE

To evaluate capillaries perfusion and retinal nerve fiber layer (RNFL) thickness diurnal changes of macular/optic disc regions among participants with or without obstructive sleep apnea-hypopnea (OSA) using spectral-domain optical coherence tomography angiography (OCTA).

METHODS

In this study, we enrolled a cohort of 35 participants including 14 patients with mild-to-moderate OSA, 12 patients with severe OSA, and 9 healthy individuals. All participants had Berlin questionnaire filled. At 20:00 and 6:30, right before and after the polysomnography examination, a comprehensive ocular examination was conducted. The systemic and ocular clinical characteristics were collected, and OCTA scans were performed repeatedly. Blood flow and RNFL thickness parameters were then exported using built-in software and analyzed accordingly.

RESULTS

After sleep, the overall vessel density (VD) variables, especially macular and choriocapillaris VDs, were relatively comparative and stable. One exception was the RPC vessel density at the inside-disc region with a decreasing trend in the mild-to-moderate group (p=0.023). RNFL changes before and after sleep in the nasal-inferior and peripapillary region were statistically significant (p=0.003; p=0.043) among three groups. And multiple testing correction verified the significant difference in diurnal changes between the mild-to-moderate group and the control group in pairwise comparisons (p=0.006; p=0.02).

CONCLUSIONS

The changes of imperceptible blood flow and RNFL thickness overnight around optic disc areas could be observed in OSA patients. Despite physiological fluctuations, aberrant diurnal changes might be useful for identifying a decrease in micro-environmental stability associated with the development of various ocular diseases such as glaucoma. Other VD variables, especially macular and choriocapillaris VDs, are relatively stable in eyes of patients having OSA with different severity.

Evaluation of Retinal Nerve Fiber Layer Thickness and Optic Nerve Head Parameters in Obstructive Sleep Apnoea Patients

PURPOSE

To study the retinal nerve fiber layer (RNFL) thickness and optic nerve head (ONH) parameters in obstructive sleep apnoea (OSA) patients and their relationship with severity of the disease.

METHODS

A cross-sectional, hospital-based study. Fifty-four OSA subjects and 54 controls were recruited. Candidate that fulfil the criteria with normal ocular examinations then proceed with spectrum domain Cirrus optical coherence tomography examinations. ONH parameters and RNFL thickness were evaluated. Apnoea-hypopnoea index (AHI) of the OSA group were obtained from the medical record.

RESULTS

In OSA, mean of average RNFL thickness was 93.87 µm, standard deviation (SD) = 9.17, p = 0.008 (p < 0.05) while superior RNFL thickness was 113.59 µm, SD = 16.29, p ≤ 0.001 (p < 0.05). RNFL thickness fairly correlate with severity of the disease (AHI), superior RNFL with R = 0.293, R2 = 0.087, p = 0.030 (p < 0.05), and nasal RNFL R = 0.292, R2 = 0.085, p = 0.032. No significant difference and correlation observed on ONH parameters. In control group, mean of average RNFL thickness was 98.96 µm, SD = 10.50, p = 0.008 (p < 0.05) while superior RNFL thickness was 125.76 µm, SD = 14.93, p ≤ 0.001 (p < 0.05).

CONCLUSIONS

The mean of the average and superior RNFL thickness were significantly lower in the OSA group compare to control. Regression analysis showed RNFL thickness having significantly linear relationship with the AHI, specifically involving the superior and nasal quadrant.

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.

The Effects of Surgical Treatment on Retina-Choroidal Findings in Patients With Obstructive Sleep Apnea Syndrome

BACKGROUND AND OBJECTIVE

The purpose of this study was to determine the effect of surgical treatment on ocular findings in obstructive sleep apnea syndrome (OSAS).

PATIENTS AND METHODS

The authors studied 34 eyes of 34 newly diagnosed OSAS patients. The sleep study was performed before and 6 months after expansion sphincter pharyngoplasty (ESP). Retinal nerve fiber layer (RNFL), choroidal thickness (CT), and retinal arteriolar caliber (RAC) analyses were performed using spectral-domain optical coherence tomography. Intraocular pressure (IOP) and ocular pulse amplitude were performed using the Pascal dynamic contour tonometer.

RESULTS

The preoperative and postoperative Apnea Hypopnea Index scores and average oxygen saturation values were significantly different (P = .0001 and P = .001, respectively). There was no significant difference between the preoperative and postoperative RNFL thicknesses (P > .05). The preoperative subfoveal, nasal, temporal CT, and IOP were significantly different from the postoperative measurements (P = .006, P = .05, P = .036, and P = .0001, respectively).

CONCLUSIONS

ESP had a significant influence on CT and IOP in patients with OSAS, maintaining a decrease in CT and IOP 6 months after surgery. The determination of these ocular findings may be useful to show the positive effects of ESP. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:35-42.].

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.

Evaluation of retinal fiber thickness and visual pathways with optic coherence tomography and pattern visual evoked potential in different clinical stages of obstructive sleep apnea syndrome

PURPOSE

To investigate the possible changes in retinal nerve fiber layer (RNFL) by optic coherence tomography and in the amplitudes and peak times (PTs) in pattern visual evoked potential (pVEP) and to compare them in obstructive sleep apnea syndrome (OSAS).

METHODS

This prospective study included patients with mild OSAS (n = 30), severe OSAS (n = 30), and 30 control subjects. All patients were assessed after obtaining the approval from our hospital's ethics committee.

RESULTS

There was no difference in age and gender between the groups (p = 0.184, p = 0.954). By analysis of variance, there was a significant difference in RNFL values among patients with mild OSAS, severe OSAS, and control for three measures of RNFL (average p = 0.044, nasal p = 0.003, inferior p = 0.027). In severe OSAS group, nasal and inferior quadrants of the RNFL were found to be thinner than the control group (p = 0.008, p = 0.031). We showed that the PT of P100 and N145 was prolonged in severe OSAS compared to the control group (p < 0.001) and that PT of P100 was prolonged in mild OSAS compared to the control group (p < 0.05). The amplitude of N75-P100 was significantly decreased in patients with both severe OSAS and mild OSAS compared to the control group (p < 0.001). Correlation of RNFL and pVEP values showed that the inferior quadrant RNFL thickness is correlated with both P100 and N145 PTs (r = 0.271*, p = 0.036 and r = 0.290*, p = 0.043, respectively) and N75-P100 amplitude (r = 0.378**, p = 0.003) in severe OSAS group.

CONCLUSIONS

In mild and severe stages of the disease, edema and inflammation were evident and VEP PT and amplitudes were affected in both groups. Furthermore, thinning in RNFL in the severe stage of the disease might be associated with higher atrophy levels and prolonged exposure to hypoxia.

Effects of CPAP for patients with OSA on visual sensitivity and retinal thickness

OBJECTIVE

Obstructive sleep apnea/hypopnea syndrome (OSA) could compromise oxygenation of the optic nerve and cause glaucomatous optic neuropathy; there has been no study to investigate the microstructure changes of the optic nerve and retina in OSA patients before and after continuous positive airway pressure (CPAP) therapy. In this study, we assess whether treatment with CPAP might improve visual sensitivity and retinal thickness in patients with OSA.

METHODS

Patients with OSA were prospectively recruited and referred for ophthalmologic evaluation at baseline and three months after CPAP treatment. Each patient underwent an ophthalmological exam, standard automated perimetry (SAP), and optical coherence tomography (OCT) exam. Peripapillary retinal nerve fiber layer (RNFL) and macular layer (ML) thickness parameters were measured. The SAP, RNFL, and ML thickness parameters before and after treatment were compared.

RESULTS

A total of 32 OSA patients were consecutively enrolled. At baseline, the mean deviation (MD) of SAP was -2.15 ± 1.90 dB (dB). After CPAP treatment, the MD was -1.38 ± 1.37 dB (p = 0.017). Regarding the OCT parameters, the inferior quadrant and nasal-inferior sector of RNFL thickness significantly improved after treatment (p = 0.025 and 0.004, respectively). The ML thickness in the superior-inner sector, inferior-outer sector, nasal-outer sector, superior hemisphere, and inferior hemisphere were also significantly improved after treatment. Improvement of ML thickness in the superior-inner sector positively correlated with the apnea/hypopnea index (r = 0.405, p = 0.022) and desaturation index (r = 0.473, p = 0.006) on pre-treatment polysomnography.

CONCLUSION

The treatment of CPAP could improve visual sensitivity and increase retinal thickness in patients with OSA.

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.

Effects of OSA Surgery on Ophthalmological Microstructures

OBJECTIVE

Obstructive sleep apnea/hypopnea syndrome (OSA) could compromise oxygenation of the optic nerve and cause glaucomatous optic neuropathy; however, there were no studies to investigate the changes of visual function and retinal microstructures in OSA patients after upper airway surgery. We aim to assess the changes in the visual sensitivity and retinal fiber layer thickness in OSA patients before and after surgery.

METHODS

This prospective single-blind study enrolled patients with OSA from a tertiary academic medical center who had unsuccessful conservative therapy and then underwent surgery. The patients were referred for comprehensive ophthalmologic evaluation at baseline and 6 months after OSA surgery. The polysomnographic findings were collected pre- and postoperatively. Visual sensitivities on standard automated perimetry (SAP) were assessed. Peripapillary retinal nerve fiber layer (RNFL) thickness and macular layer (ML) thickness parameters were measured by spectral-domain optical coherence tomography (OCT).

RESULTS

A total of 108 OSA patients were enrolled. Six months after surgery, the major parameters of polysomnography (PSG), mean deviation, and pattern standard deviation of SAP significantly improved in these OSA patients. Regarding the OCT parameters, thickness of ML in the nasal-outer, superior-inner, temporal-inner, inferior-inner, nasal-inner sectors, and total ML thickness significantly increased 6 months after upper airway surgery in the severe OSA group (apnea/hypopnea index ⩾30 per hour).

CONCLUSION

The visual sensitivities on SAP, ML thickness on OCT, and oxygenation status on PSG significantly improved 6 months after upper airway surgery in patients with severe OSA. Upper airway surgery may ameliorate the microstructures of the retina in patients with severe OSA.

The role of optical coherence tomography in therapeutics and conditions, which primarily have systemic manifestations: a narrative review

Optical coherence tomography is designed to evaluate in vivo qualitative and quantitative changes of the anterior segment, optic nerve and the retina. Initial applications of this technology were confined mainly to ophthalmic diseases. However recently, numerous studies have evaluated its use in systemic conditions and in therapeutics where, optic nerve and retinal architecture can be assessed to monitor progression of systemic conditions and its response to treatment. This is a narrative review aimed at evaluating the debate surrounding the role of spectral domain optical coherence tomography, in systemic conditions where optic nerve affection can be measured and be used in the diagnosis, monitoring and assessment of treatment effect as a non-invasive, quick, novel technique.

Evaluation of Intraocular pressure, Corneal thickness, and Retinal nerve fiber layer thickness in patients with Obstructive Sleep Apnea Syndrome

Objective:

To evaluate the intraocular pressure (IOP), central corneal thickness (CCT), and peripapillary retinal nerve fiber layer (RNFL) thickness in Patients with Obstructive Sleep Apnea Syndrome.

Methods:

In this prospective study, 103 patients with OSAS (study group) and 37 healthy subjects were enrolled. All participants underwent comprehensive ophthalmic examinations. Mean outcome measures were intraocular pressure by Goldmann applanation tonometry, CCT measurement using ultrasound pachymeter and peripapillary RNFL thickness measured by spectral-domain optical coherence tomography.

Results:

The differences between the mean values of RNFL thickness in all quadrants were similar in both groups and were not statistically significant (p=0.274). The IOP and CCT measurement averages of all patients with OSAS were lower than the control group. However, this difference was not statistically significant. There was no correlation between the apnea-hypopnea index, lowest oxygen saturation (LAST) or Body Mass Index (BMI) and the peripapillary RNFL thickness, IOP or CCT when OSAS group was divided by severity.

Conclusions:

The study results suggest that peripapillary RNFL thickness, IOP or CCT did not differ significantly between OSAS and control groups. We also found no correlation between apnea severity (AHI), lowest oxygen saturation (LAST) and BMI and RNFL, CCT and IOP.

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.

Peripapillary retina nerve fiber layer thickness and macular ganglion cell layer thickness in patients with obstructive sleep apnea syndrome

PurposeTo investigate the association of the severity of obstructive sleep apnea syndrome (OSAS) with peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GC-IPL).Materials and methodsIn this cross-sectional study, 145 patients with OSAS and 40 healthy subjects were enrolled. OSAS patients were further divided into mild (n=50), moderate (n=36), and severe (n=59) OSAS groups according to their apnea-hypopnea index (AHI) values. Spectral-domain optical coherence tomography was used to measure the peripapillary RNFL and GC-IPL thicknesses.ResultsThere was no statistical difference between the RNFL thickness in OSAS and control groups (P>0.05). Both average GC-IPL and minimum GC-IPL thicknesses were significantly lower in severe OSAS group than in healthy controls (P<0.05 for both). There was a significant negative correlation between AHI and both average GC-IPL (r=-0.232, P=0.005) and minimum GC-IPL (r=-0.233, P=0.005) thicknesses.ConclusionsOur study results suggest that although RNFL thickness did not differ significantly between OSAS and control groups, ganglion cell layer thickness in OSAS patients is much lower than in healthy population. Ganglion cell thickness showed a significant correlation with the severity of OSAS.

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.

Retinal Nerve Fiber Layer Thickness Alteration in Apneic Children

PURPOSE

We examined retinal nerve fiber layer (RNFL) thickness alterations in children with chronic upper airway obstructions (UAOs) and obstructive sleep apnea syndrome (OSAS). We also investigated whether it was affected by an adenotonsillectomy operation.

METHODS

Forty-two children aged 3 to 8 years with chronic UAO resulting from adenotonsillar enlargement and 34 age-matched controls were included in the study. Patients underwent a Brouillette scoring questionnaire to be divided into mild (N = 10), moderate (N = 22), severe (N = 10), and total (N = 42) UAO groups. According to the scoring, the severe UAO group was defined as the severe OSAS group, the moderate group was suspicious for OSAS, and the mild UAO group was defined as the non-OSAS group. The patients' demographic data for age, sex, and body mass index were obtained. Ophthalmologic evaluations were performed with optical coherence tomography. Central corneal thickness, macular thickness, intraocular pressure (IOP), and RNFL thickness were measured. An adenotonsillectomy was performed on all patients, and eye examinations and scoring were repeated after the surgery.

RESULTS

Higher IOP levels were obtained between the total UAO group and the control group (p > 0.05). There were significant differences between UAO groups and the control group except for the moderate UAO group. There was no significant difference in RNFL thickness (p > 0.05) between preoperative UAO groups and the control group. However, after surgery, some significant differences emerged in the superior, inferior, and average RNFL thickness (p < 0.05). Also, IOP levels were significantly lower in the mild, moderate, and total UAO groups after the operation (p < 0.05).

CONCLUSIONS

Upper airway obstruction and OSAS seem to worsen some RNFL and IOP parameters in children, and eye examinations may be useful in these patients.

Assessment of the retinal nerve fiber layer in individuals with obstructive sleep apnea

Background

The effect of obstructive sleep apnea (OSA) syndrome in the peripapillary retinal nerve fiber layer (RNFL) thicknesses remains unclear. The purpose of this study was to assess RNFL measurements acquired using scanning laser polarimetry (SLP) and optical coherence tomography (OCT) in patients with OSA.

Methods

The sample of this cross-sectional study included 40 OSA patients and 45 age-matched controls, consecutively and prospectively selected. All participants underwent at least one reliable standard automated perimetry (SAP) test, while RNFL measurements were obtained using the SLP and OCT. The OSA group was divided into 3 sub-groups based on the apnea/hypopnea index (AHI): mild, moderate, or severe OSA. SAP, SLP, and OCT outcomes were compared between the control and OSA groups. The relationship between AHI and RNFL parameters was also evaluated.

Results

Age was not different between both groups. Mean deviation of SAP was −0.47 ± 0.9 dB and −1.43 ± 2.3 dB in the control and OSA groups, respectively (p = 0.01). RNFL thickness measured with OCT was similar between groups. OSA patients showed increased nerve fiber indicator (NFI; 20.9 ± 7.9 versus 16.42 ± 7.82; p = 0.01) and decreased superior average (59.74 ± 10.35 versus 63.73 ± 6.58; p = 0.03) obtained with SLP compared with healthy individuals. In the total sample, NFI and AHI were moderately correlated (r = 0.358; p = 0.001). In severe OSA subjects (n = 22), NFI and AHI had a Spearman correlation coefficient of 0.44 (p = 0.04).

Conclusion

RNFL thickness measured with OCT did not differ significantly between groups. Severe OSA was related to a reduction of the RNFL thickness assessed by SLP.

Retina nerve fiber layer and choroidal thickness changes in obstructive sleep apnea syndrome

OBJECTIVES

The purpose of this study was to determine the effects of obstructive sleep apnea syndrome (OSAS) on the submacular and peripapillary retinal nerve fiber layer (RNFL) and choroidal thickness (ChT).

METHODS

Eighty-four eyes of 42 male patients with OSAS and 112 eyes of 56 aged-matched and body mass index-matched healthy male subjects were enrolled in this case-control study. The ChT and peripapillary RNFL thickness was measured using enhanced depth imaging optical coherence tomography. The ChT and RNFL thickness measurements of the groups were compared, and correlations among the Apnea Hypopnea Index (AHI) values and these measurements were calculated. Right and left eyes were separately evaluated.

RESULTS

There were no significant differences in the subfoveal and temporal ChT between the groups (p > 0.05). The OSAS group had significantly thicker ChT at 0.5 and 1.5 mm nasal to the fovea in both eyes than the control group (p < 0.05). The peripapillary ChT were significantly thicker in the OSAS group at all segments except for the temporal and superotemporal segments when compared with the control group (p < 0.05 for all quadrants except temporal and superotemporal). When compared with controls, the OSAS group had significantly thinner nasal RNFL thickness in the right eye (p = 0.01) and thinner mean RNFL thickness in both eyes (p < 0.001). Other RNFL thickness measurements were similar between groups (p > 0.05). Between AHI and mean RNFL thickness showed a median negative correlation (r = - 0.411, p = 0.001).

CONCLUSION

The choroidal thickening in patients with OSAS may be associated with the pathophysiology of the neurodegeneration process of the disease.

Glaucoma and its association with obstructive sleep apnea: A narrative review

Obstructive sleep apnea (OSA) is one of the systemic risk factors for glaucoma which causes irreversible visual field (VF) damage. We reviewed the published data of all types of studies on the association between these two conditions and papers regarding functional and structural changes related to glaucomatous damage using Scopus, web of science, and PubMed databases. There is evidence that the prevalence of glaucoma is higher in OSA patients, which independent of intraocular pressure (IOP). Studies have reported thinning of retinal nerve fiber layer (RNFL), alteration of optic nerve head, choroidal and macular thickness, and reduced VF sensitivity in patients of OSA with no history glaucoma. A negative correlation of apnea-hypopnea index with RNFL and VF indices has been described in some studies. Raised IOP was noted which is possibly related to obesity, supine position during sleep, and raised intracranial pressure. Diurnal fluctuations of IOP show more variations in OSA patients before and after continuous positive airway pressure (CPAP) therapy when compared with the normal cases. The vascular factors behind the pathogenesis include recurrent hypoxia with increased vascular resistance, oxidative stress damage to the optic nerve. In conclusion, comprehensive glaucoma evaluation should be recommended in patients with OSA and should also periodically monitor IOP during CPAP treatment which may trigger the progression of glaucomatous damage.

The clinical utility of measuring the macular outer retinal thickness in patients with glaucoma

PURPOSE

Few optical coherence tomography (OCT) studies have investigated outer retinal thickness including the photoreceptor layer in glaucoma. We measured changes in the macular outer retinal thicknesses using OCT in patients with glaucoma with an average follow-up of 2.9 ± 0.8 years.

METHODS

A total of 39 eyes of 39 patients with primary open-angle glaucoma were analyzed. The RTVue-100 was used to measure the macular outer retinal, macular ganglion cell complex, and circumpapillary retinal nerve fiber layer thicknesses, global loss volume, and focal loss volume. Using the paired t test, baseline parameters were compared with those at the last follow-up.

RESULTS

The average baseline mean deviation value in the Humphrey Field Analyzer was -2.13 dB. The ganglion cell complex thickness significantly decreased over the follow-up period (baseline thickness, 79.66 ± 7.71 μm; final thickness, 76.79 ± 7.39 μm; p&lt;0.001). There were significant differences between baseline and final visit measurements for circumpapillary retinal nerve fiber layer thickness, global loss volume, and focal loss volume (p&lt;0.001, p&lt;0.001, and p = 0.004, respectively). However, there was no significant change in outer retinal thickness (baseline thickness, 167.56 ± 7.26 μm; final thickness, 167.25 ± 7.93 μm; p = 0.540).

CONCLUSIONS

Outer retinal thickness was not altered during the follow-up period. The stability of outer retinal thickness may indicate the reliability of OCT analysis for glaucoma follow-up.

Thickness alterations of retinal nerve fiber layer in children with sleep-disordered breathing due to adenotonsillar hypertrophy

OBJECTIVE

This study is designed to assess whether hypoxia which is caused by apnea and hypopnea episodes, has an effect on retinal nerve fiber layer (RNFL) thickness, using optical coherence tomography (OCT) in pediatric patients with Adenotonsillar hypertrophy (ATH).

METHODS

Fifty-seven children patient with AHT, and 31 healthy non-AHT children (between 6 and 12 ages) were enrolled in this study. Obstructive symptoms of the patients with ATH were assessed by using OSA-18 survey. The patients were divided into 2 groups as mild (>60 and <80) and severe (>80) OSAS patients, according to OSA-18 survey total scores. RNFL thickness, in the four quadrants (superior, nasal, inferior and temporal) patient's both eyes, was measured by optical coherence tomography. RNFL parameters of control and patient groups were compared. Correlation between OSA survey scores and RNFL thickness of the patient groups were examined.

RESULTS

A positive correlation was found between ages and RNLF thickness of all subjects enrolled in this study (r=+0.107, p<0.05). And also a poor correlation was found between OSA-18 survey scores and RNFL parameters in patient group (between -0.031 and +0.016 at right and left eyes, p>0.05). No statistically significant alteration in RNFL thickness was found between the patient and control groups (p>0.05).

CONCLUSION

Age range (6-12) of the patients with ATH in our study considers that possible OSAS time was not long enough to affect RNLF thickness. Remembering the risk of optic injury development in children with ATH (in a long term), tonsillectomy and/or adenoidectomy operations shouldn't be delayed.

Obstructive sleep apnea and optic neuropathy: is there a link?

Over the last decade, there has been an emerging interest in the link between obstructive sleep apnea (OSA) and ocular health. Though the evidence for OSA playing a role in cerebrovascular disease risk seems clear, the same cannot be said for optic neuropathies. The association between OSA and glaucoma or non-arteritic anterior ischemic optic neuropathy (NAION) has been postulated to be secondary to direct hypoxia or mechanisms of optic nerve head vascular dysregulation. Papilledema and increased intracranial pressure have also been reported in OSA and are thought to be due to increased cerebral perfusion pressure and cerebral venous dilation secondary to hypoxia and hypercapnia. This article reviews the evidence for possible pathophysiological links between OSA and optic nerve pathology. The epidemiologic and clinical evidence for an association, direct or indirect, between OSA and glaucoma, non-arteritic anterior ischemic optic neuropathy (NAION), and papilledema or idiopathic intracranial hypertension is presented.

Relationship between severity of obstructive sleep apnea syndrome and retinal nerve fiber layer thickness

PURPOSE

To determine whether there is a significant correlation among the peripapillary retinal nerve fiber layer (RNFL) thickness, foveal thickness, total macular volume, and severity of obstructive sleep apnea syndrome.

DESIGN

Prospective study.

METHODS

We studied 124 consecutive subjects who underwent polysomnography. Optical coherence tomography (OCT) was used to measure the peripapillary RNFL, foveal thickness, and total macular volume. The Pearson correlation coefficient was used to determine the relationship between the apnea-hypopnea index and OCT and other parameters. Multiple regression analysis was used to determine the independent factors for the RNFL sectors that were the most strongly correlated with the apnea-hypopnea index.

RESULTS

The apnea-hypopnea index was significantly and negatively correlated (right eye, r = -0.31, P = 0.0004; left eye, r = -0.39, P < 0.0001) with the nasal RNFL thickness (Pearson correlation analysis). The foveal thickness and total macular volume were not correlated. The intraocular pressure, body mass index, plaque score, and incidence of hypertension were negatively correlated, and the lowest oxygen saturation and mean oxygen saturation were positively correlated with the nasal RNFL thickness in the left eye. Multiple regression analysis showed that the apnea-hypopnea index and age were independent contributors to the nasal RNFL thickness in the left eye (apnea-hypopnea index, standard regression coefficient, -0.30, t value, -2.76, P = 0.007; age, -0.24, -2.36, 0.02, respectively). The nasal RNFL thickness in both eyes decreased significantly based on the severity of the obstructive sleep apnea syndrome.

CONCLUSION

Exacerbation of obstructive sleep apnea syndrome may produce unique retinal neurodegenerative disorders that decrease the nasal RNFL thickness.

Obstructive sleep apnea-hypopnea syndrome (OSAHS) and glaucomatous optic neuropathy

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is becoming widely accepted as a risk factor for glaucoma. We discuss the proposed mechanism involved in the pathogenesis of glaucoma in OSAHS, and review the published data on the association between these two conditions, as well as papers regarding functional and structural tests related with glaucomatous damage. There is increasing evidence that the prevalence of glaucoma is higher in OSAHS patients, especially in those with severe disease with apnea-hypopnea index (AHI) >30, and also that sleep disorders may be more frequent in patients with glaucoma, especially in those with normal tension glaucoma (NTG). Several ophthalmic signs and symptoms have been associated with this condition. Raised intraocular pressure (IOP), possibly related to increased body mass index, thinning of retinal nerve fiber layer (RNFL), and alteration of visual field (VF) indices has been demonstrated in many studies, in patients with no history of glaucoma or evidence of glaucomatous changes in the ophthalmic examination. A correlation of AHI with RNFL and VF indices has been described in some studies. Finally, corneal thinning, suspicious glaucomatous disc changes and anomalies in electrophysiological tests such as multifocal visual evoked potential have been described in patients with OSAHS, even in patients with normal findings in the optic nerve and VF, suggesting subclinical optic nerve involvement not detectable in conventional ophthalmic examinations. The pathogenesis of optic nerve involvement has been related to vascular and mechanical factors. Vascular factors include recurrent hypoxia with increased vascular resistance, autonomic deregulation, oxidative stress and inflammation linked to hypoxia and subsequent reperfusion, decreased cerebral perfusion pressure and direct hypoxic damage to the optic nerve. Proposed mechanical factors include increased IOP at night related to supine position and obesity, raised intracranial pressure and elastic fiber depletion in the lamina cribosa and/or trabeculum. In conclusion, ophthalmic evaluation should be recommended in patients with severe OSAHS, and the presence of sleep disorders should be investigated in patients with glaucoma, especially in NTG patients and in those with progressive damage despite controlled IOP, as treatment with continuous positive airway pressure may contribute to stabilizing the progression of glaucomatous damage.