The eye and sleep apnea

Nocturnal hypoxia and age-related macular degeneration

BACKGROUND

Nocturnal hypoxia is common, under-diagnosed and is found in the same demographic at risk of age-related macular degeneration (AMD). The objective of this study was to determine any association between nocturnal hypoxia and AMD, its severity, and the high-risk sub-phenotype of reticular pseudodrusen (RPD).

METHODS

This cross-sectional study included participants aged ≥50 years with AMD, or normal controls, exclusive of those on treatment for obstructive sleep apnoea. All participants had at home, overnight (up to 3 nights) pulse oximetry recordings and multimodal imaging to classify AMD. Classification of Obstructive Sleep Apnea (OSA) was determined based on oxygen desaturation index [ODI] with mild having values of 5-15 and moderate-to-severe >15.

RESULTS

A total of 225 participants were included with 76% having AMD, of which 42% had coexistent RPD. Of the AMD participants, 53% had early/intermediate AMD, 30% had geographic atrophy (GA) and 17% had neovascular AMD (nAMD). Overall, mild or moderate-to-severe OSAwas not associated with an increased odds of having AMD nor AMD with RPD (p ≥ 0.180). However, moderate-to-severe OSA was associated with increased odds of having nAMD (odds ratio = 6.35; 95% confidence interval = 1.18 to 34.28; p = 0.032), but not early/intermediate AMD or GA, compared to controls (p ≥ 0.130). Mild OSA was not associated with differences in odds of having AMD of any severity (p ≥ 0.277).

CONCLUSIONS

There was an association between nocturnal hypoxia as measured by the ODI and nAMD. Hence, nocturnal hypoxia may be an under-appreciated important modifiable risk factor for nAMD.

Looking beyond in Sleep Medicine Practice: Effect of OSA Management in Floppy Eyelid Syndrome - A Case Report

Obstructive Sleep Apnea Syndrome (OSA) is a common sleep disorder characterized by recurrent episodes of partial or complete upper airway obstruction during sleep. Floppy Eye Syndrome (FES) is a condition in which the upper eyelids easily evert with upward traction due to underlying tarsal plate laxity and is associated with chronic, reactive papillary conjunctivitis; this causes the eye to be vulnerable to discomfort and visual symptoms. A 49-year-old man with an 8-year history of snoring, sleep fragmentation, and daytime sleepiness was admitted as an outpatient in our sleep clinic. The patient had complied ocular symptoms such as burning eyes, redness, and irritative ocular symptoms in the past five years, arising upon waking up. The symptoms did not regress with the use of artificial tears and proper ointment. The patient was diagnosed with OSA and began using continuous positive airway pressure (CPAP). CPAP therapy significantly corrected the symptoms of FES associated with OSA . This would help to sensibilize ocular findings in patients with OSA and identify hidden sleeping diseases needing a more appropriate investigation and possible treatment. We must look beyond our approach to sleep clinic patients and avoid being kept to the common symptoms patients represent.

Prevalence of Obstructive Sleep Apnea With Floppy Eyelid Syndrome: A Systematic Review and Meta-analysis

PURPOSE

This study investigated the prevalence of obstructive sleep apnea (OSA) in floppy eyelid syndrome (FES) patients and evaluated the severity of OSA with FES prevalence.

METHODS

Cochrane CENTRAL, Medline, Science Direct, Google Scholar, and PubMed databases were searched for studies on FES patients and its association with OSA syndrome, of any design, published from January 1, 1997, to January 1, 2022. A random-effects model that weighted the studies was used when there was heterogeneity between studies ( p < 0.10) and if I 2 values were more than 50%. All p values were 2-tailed and considered statistically significant if <0.05.

RESULTS

A total of 12 studies comprising 511 patients were included in this meta-analysis. Of these, 368 were male (77.6%) and the average age was 55.10 years. The overall prevalence of OSA in FES patients was 57.1% (95% CI: 46.5-74.8%), M:F ratio was 48:1 (98% male), and 69.1% of patients received their OSA diagnosis at the time of the study. Of those with FES, tear film abnormalities were the most common ocular comorbidity (78.9%) followed by keratoconus (20.6%), glaucoma (9.8%), and lower eyelid ectropion (4.6%). Obesity was the most common systemic morbidity (43.7%) followed by hypertension (34.0%) and diabetes mellitus (17.9%).

CONCLUSION

This meta-analysis demonstrates OSA is a common comorbidity in the FES population. Ophthalmologists are often the first to evaluate patients with FES, and considering this coincidence, routine screens for sleep apnea symptoms in at-risk FES patients should be undertaken. Large case-control studies are required to better elucidate the exact prevalence of OSA and other morbidities in patients with FES, and to better understand the etiology of FES.

Association between obstructive sleep apnea and floppy eyelid syndrome: A systematic review and metaanalysis

RATIONALE

Obstructive sleep apnoea (OSA) has been linked to various ocular disorders, including floppy eyelid syndrome (FES). Previous studies have hypothesised the underlying association between the 2 , but results are currently still inconclusive.

OBJECTIVE

To investigate the association between OSA and FES.

METHODS

Four databases (Pubmed, Embase, Scopus, and Cochrane Library) were searched from inception until 28 February 2022 for observational studies and randomized controlled trials assessing the association between OSA and FES. Two reviewers selected studies, extracted data, graded the risk of bias using the Newcastle-Ottawa scale and the quality of assessment using the Grading of Recommendations Assessment, Development, and Evaluation system. Random-effects models were used to metaanalyze the associations.

RESULTS

Twelve studies were included in the systematic review, of which nine were suitable for metaanalysis, with a combined cohort of 1,109 patients. Risk of bias was low to moderate. The overall analysis showed a significant positive association between OSA and FES (OR = 1.89, 95% CI = 1.27-2.83, I 2 = 44%). Further analysis revealed that the more severe the OSA was, the higher the risk of developing FES. Patients with severe OSA had the nominally highest risk of developing FES (OR = 3.06, 95% CI = 1.62-5.78, I 2 = 0%), followed by moderate OSA (OR = 2.53, 95% CI = 1.29-4.97, I 2 = 0%), and patients with mild OSA had the lowest risk (OR = 1.76, 95% CI = 0.85-3.62, I 2 = 0%).

CONCLUSION

Our metaanalysis reports a positive association between OSA and FES, with increasing severity of OSA correlating with a significantly higher risk of FES. More longitudinal studies with sufficient duration of follow-up are needed to better characterise the relationship between OSA and FES.

Lax eyelid condition (LEC) and floppy eyelid syndrome (FES) prevalence in obstructive sleep apnea syndrome (OSA) patients: a systematic review and meta-analysis

Purpose

Lax eyelid condition (LEC) and floppy eyelid syndrome (FES) represent two distinct conditions which have been associated with several ocular and systemic comorbidities. The main aim of this systematic review and meta-analysis is to explore the available literature to estimate the prevalence rate of LEC and FES in obstructive sleep apnea (OSA).

Methods

The protocol of this systematic review and meta-analysis has been registered in PROSPERO. Four electronic databases (PubMed/MEDLINE, Google Scholar, Cochrane Library, Web of Science) were searched from inception to December 24, 2021. A random intercept logistic regression model was carried out for the analysis of overall proportions. Odds ratio and mean difference were reported as measures of the effect size in the presence of binary and continuous outcomes, respectively. The estimated numbers of LEC/FES patients in OSA were calculated by multiplying the prevalence rate determined by our random-effects model and the corresponding Benjafield et al.’s population prospect.

Results

We included 11 studies comprising 1225 OSA patients of whom 431 and 153 affected by LEC and FES, respectively. Our model estimated a pooled prevalence rate for LEC and FES in OSA patients of 40.2% (95%CI: 28.6–53.1%) and of 22.4% (95%CI: 13.8–34.2%), respectively. The number of LEC/FES affected individuals among OSA patients is expected to peak up to 376 and to 210 million, respectively. OSA patients appeared to have a 3.4 (95%CI: 2.2–5.2) and a 3.0 (95%CI: 1.7–5.5) increased risk of developing LEC and FES than the healthy counterpart.

Conclusion

Prevalence of LEC and FES is higher in OSA-affected patients compared to controls. More studies are warranted to investigate the mechanisms leading to the development of LEC and/or FES in OSA patients, as well as the feasibility of the adoption of these clinical findings as screening tools for OSA.

Sleep and eye disease: A review

There is a growing body of literature on the effects of sleep disorders, in particular obstructive sleep apnoea (OSA), on ocular health, with consistent evidence of an increased risk of floppy eyelid syndrome, non-arteritic anterior ischaemic optic neuropathy, diabetic macular oedema, and other retinal vasculature changes in individuals with OSA. However, reports on OSA's associations with glaucoma, papilloedema, diabetic retinopathy, central serous chorioretinopathy, and keratoconus have been conflicting, while links between OSA and age-related macular degeneration have only been described fairly recently. Despite numerous suggestions that OSA treatment may reduce risk of these eye diseases, well-designed studies to support these claims are lacking. In particular, the ocular hypertensive effects of continuous positive airway pressure (CPAP) therapy for OSA requires further investigation into its potential impact on glaucoma risk and management. Reports of ocular surface complications secondary to leaking CPAP masks highlights the importance of ensuring good mask fit. Poor sleep habits have also been linked with increased myopia risk; however, the evidence on this association remains weak.

Alterations of Ocular Surface and Tear Film in Patients with Obstructive Sleep Apnea/Hypopnea Syndrome

PURPOSE

Obstructive sleep apnea/hypopnea syndrome (OSA) results in repeated oxygen desaturation, repeated arousals, and episodic nocturnal activation of sympathetic nervous system during sleep. Untreated OSA is strongly associated with an increase of cardio- and cerebrovascular disorders, as well as the damages of ophthalmological microstructures. However, previous literature only simply studied the association between the ophthalmic disorders and OSA. In the present study, we first investigated the alterations of ocular surface and tear film non-invasively with the innovated corneal topographer in untreated OSA patients and normal control subjects. Furthermore, we analyzed in depth whether the correlations between OSA severity and ocular surface exams exist.

PARTICIPANTS AND METHODS

Participants underwent a full-night polysomnography to determine OSA occurrence and severity. All participants subsequently received Ocular Surface Disease Index questionnaire and comprehensive ocular exams, including floppy eyelid syndrome (FES) assessment, oculus scan for tear meniscus height, non-invasive keratograph tear film breakup time (NIKBUT), and ocular surface redness, endothelial cell density, and corneal fluorescein staining.

RESULTS

One hundred eighty-one participants were prospectively enrolled in the study. FES was found in 11.5% of the normal control group and 60.0% of the severe OSA group (p=0.0005). There were significant differences in the first-NIKBUT (F-NIKBUT) (p < 0.0001), average-NIKBUT (A-NIKBUT) (p = 0.0007), and redness scores over the nasal bulbar (p = 0.032), temporal bulbar (p < 0.0001), nasal limbal (p = 0.014), and temporal limbal (p < 0.0001) areas among the four groups. F-NIKBUT and A-NIKBUT were significantly shorter in the moderate/severe OSA group (apnea/hypopnea index (AHI) ≥15) than in the normal/mild OSA group (AHI <15) (both p < 0.0001). The redness scores over the temporal bulbar (p < 0.0001) and temporal limbal (p < 0.0001) areas were also significantly different in these two OSA groups. Moreover, F-NIKBUT and A-NIKBUT negatively correlated with AHI. Nasal bulbar redness, temporal bulbar redness, nasal limbal redness, and temporal limbal redness positively correlated with AHI.

CONCLUSION

OSA patients had higher occurrence of FES. The NIKBUT was significantly shorter, and the temporal conjunctival redness scores over bulbar and limbal areas were higher in the moderate/severe OSA group than in the normal/mild OSA group. NIKBUT and conjunctival hyperemia significantly correlated with the severity of untreated OSA.

Early corneal and optic nerve changes in a paediatric population affected by obstructive sleep apnea syndrome

PURPOSE

The relation between OSAS and eye diseases is well known in adults, while very few and contradictory data can be found regarding paediatric ages. The aim of this study is to explore the early corneal, macular and optic nerve changes in paediatric patients with OSAS.

METHODS

Prospective study that enrolled children aged ≥ 4 years referred to the Paediatric Pneumology Clinic in Verona for suspected obstructive sleep apnoea syndrome (OSAS) and investigated with the overnight respiratory polygraphy. Patients with apnoea-hypopnea index (AHI) > 1 were classified as OSAS, while those with AHI < 1 were classified non-OSAS. All patients underwent comprehensive eye examination including slit lamp, refraction, intraocular pression (Goldman applanation tonometry), corneal tomography (corneal astigmatism, corneal keratometry at the apex, surface asymmetry index, central corneal thickness and thinnest corneal thickness) and optical coherence tomography (central macular thickness, macular volume and retinal nerve fibre layer).

RESULTS

Seventy-two children were enrolled in the study. The overall prevalence of OSAS was 48.6%. Statistically significant differences were found between OSAS and non-OSAS group for corneal asymmetry (0.9 ± 0.5 and 0.6 ± 0.3, respectively; p = 0.02), thinnest corneal thickness (551.8 ± 33.9 and 563.7 ± 32.5; p = 0.04), average retinal nerve fibre layer (102.8 ± 10.5 µm and 98.1 ± 12.3 µm; p = 0.012) and in nasal quadrant (76.2 ± 15.4 µm and 66.5 ± 12.6 µm; p = 0.0002).

CONCLUSIONS

A comprehensive eye examination with corneal and optic nerve imaging showed early corneal and optic nerve changes in children newly diagnosed with OSAS. These could be prelude of the known ocular manifestations associated with OSAS in adult patients.

Comparison of obstructive sleep apnea syndrome and keratoconus patients on elevation maps

PURPOSE

This study aimed to compare the tomographic features of the cornea on elevation maps between obstructive sleep apnea syndrome (OSAS) and keratoconus (KC) patients and to investigate the presence of susceptibility to ectatic corneal diseases in OSAS patients.

DESIGN

This is a comparative cross-sectional case-control study.

METHODS

This study included 84 eyes of 42 patients diagnosed with severe OSAS using polysomnography (apnea/hypopnea index > 30), 84 eyes of 56 patients diagnosed with keratoconus, and 84 eyes of 42 healthy subjects as control group and evaluated in three groups. Elevation maps of all the groups were performed using Pentacam, and topometric, pachymetric, and deviation indices were recorded.

RESULTS

The study included 252 eyes of 130 participants divided in three groups. Comparing all the tomographic keratometric values, a significant difference was found among the three groups. All keratometric values were found to be higher in the OSAS patients group compared to those in the control group. Also topometric indices and Belin-Ambrosio enhanced ectasia display (BAD) were observed to be higher as in subclinical keratoconus and statistically significant when compared to those in the control group.

CONCLUSION

The study reveals the tomographic corneal characteristics and topometric and pachymetric indices of patients with severe OSAS at the time of diagnosis; these findings statistically significantly differ from the control group. In addition to the known association of floppy eyelid in OSAS patients, the suspicion of keratoconus should be kept in mind.

Relationship between Obstructive Sleep Apnea and Central Serous Chorioretinopathy: A Health Insurance Database Study

Purpose: To evaluate the association between obstructive sleep apnea (OSA) and central serous chorioretinopathy (CSCR).Methods: A retrospective, cohort, longitudinal study was conducted using the national health insurance database in Taiwan between 1996 and 2013. Patients diagnosed with OSA were enrolled after exclusion, and a control group with similar age, gender, and major systemic co-morbidities were included in a 1:1 ratio by propensity score matching. The primary outcome is the occurrence of CSCR, and patients with CSCR were categorized via severity for further analysis. The percentage of incident CSCR in the OSA group and control groups and the adjusted hazard ratios (aHR) of CSCR were determined by Cox proportional hazard regression.Results: There were 13,084 patients enrolled in both the OSA group and control groups, respectively. The total event of CSCR was 50 (0.4%) in the OSA group and 25 (0.2%) in the control group (P < .001). Moreover, the OSA group has an increased aHR of 1.9 (P = .012) for developing CSCR. In the subgroup analysis, patients with OSA aged from 30 to 39 and 50 to 59 demonstrated higher risk of developing CSCR compared to the control group, and the presence of OSA would lead to a higher incidence of mild CSCR (all P < .05).Conclusions: OSA patients aged from 30 to 39 and 50 to 59 have a higher risk of developing CSCR, while the severity of CSCR will not be worsen by OSA.

Association of obstructive sleep apnea/hypopnea syndrome with glaucomatous optic neuropathy and ocular blood flow

The present study aimed to investigate the prevalence of glaucomatous optic neuropathy in patients with obstructive sleep apnea/hypopnea syndrome (OSAHS). In total, 83 subjects (45 cases of severe OSAHS and 38 controls) underwent polysomnographic assessment and were evaluated for the severity of the disease using the Apnea-Hypopnea index. A detailed ophthalmologic exam was then performed, including measurement of the intraocular pressure (IOP) with a Goldmann applanation tonometer and Pascal dynamic contour tonometer (DCT), recording of the ocular pulse amplitude measured by the Pascal DCT, standard automated perimetry and retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thickness evaluation using optical coherence tomography. Ocular blood flow was assessed using color Doppler imaging (CDI) and ophthalmic artery indices were evaluated, including peak systolic blood velocity, end diastolic blood velocity and resistivity index (RI). There was a significant difference in the mean IOP between controls (11.03±3.85 mmHg) and cases of severe OSAHS (18.06±3.39 mmHg) when the IOP was measured by DCT (P<0.0001), but not with the Goldmann applanation tonometer (IOP, 13.97±2.85 mmHg for controls and 14.89±3.21 mmHg for cases of severe OSAHS; P=0.0877). Significant negative correlations were observed between RNFL thickness and RI (P=0.0011) in cases of severe OSAHS, as well as between GCC thickness and RI (P<0.008) in all subjects. Furthermore, a negative correlation between RI and RNFL thickness in severe cases of OSAHS suggested a hemodynamically induced vulnerability of RNFL in OSAHS. The correlation between RI and GCC thickness in all subjects suggested that impaired perfusion, more prominent in OSAHS, leads to structural changes. Therefore, cases of severe OSAHS should be monitored for changes in RNFL and GCC thickness, as well as CDI findings. Furthermore, patients with increased ophthalmic artery RIs should be monitored for changes in the GCC, regardless of the etiology of the RI increase.

Prevalence of Glaucoma in Patients with Obstructive Sleep Apnea

To determine the prevalence of glaucoma in obstructive sleep apnea (OSA) patients and compare it with that of patients without OSA. Patients investigated for OSA using polysomnography at the sleep center of King Abdulaziz University Hospital were invited to participate in this cross-sectional case series study. American Academy of Sleep Medicine guidelines were used to diagnose OSA. Recruitment of patients with and without OSA was conducted from December 2013 to September 2015. Exclusion criteria included topical and systemic steroid use and presence of other ocular diseases. Two criteria, cup/disc ratio and visual field defects, were necessary for a glaucoma diagnosis. Among 84 adults enrolled, 44 (52%) had a confirmed diagnosis of OSA. Glaucoma prevalence was higher among individuals with OSA (16%) than among non-OSA individuals (8%), a difference that was not statistically significant. A consistent trend, which was not statistically significant after adjusting for cofounders, toward more glaucomatous changes was observed in OSA subjects. Although a trend toward higher glaucoma prevalence was observed in OSA patients, the difference was not statistically significant. As many variables contribute to the development of the two conditions, larger cohorts are needed to evaluate associations between glaucoma and OSA.

Effect of Obstructive Sleep Apnea on Corneal Morphological Characteristics

PURPOSE

To determine central corneal thickness (CCT) and the corneal parameters in patients with obstructive sleep apnea (OSA), evaluate the relationship between the severity of OSA, minimum peripheral capillary oxygen saturation (min. SpO2), and corneal morphological characteristics.

METHODS

Patients with OSA diagnosed by full-night polysomnography before treatment were included. Patients with OSA were divided into 3 groups according to the Apnea-Hypopnea Index (AHI). The control group (CG) was examined to exclude the possibility of OSA and ocular diseases. The following data were recorded: age, sex, body mass index, ophthalmologic evaluation, and the results of polysomnography.

RESULTS

A total of 114 eyes were studied: 74 eyes of patients with OSA and 40 eyes of the CG. The mean age was 57 ± 6 years. The mean values of CCT and endothelial cell density (ECD) varied significantly between the patients and the CG (P < 0.001). The mean values of CCT, ECD, cell variation coefficient (CV), and hexagonal cell percentage (HEX) in the group of patients with OSA were 535.28 ± 21.32 μm, 2632 ± 333, cells/mm. 31.8 ± 3.9, and 55.6 ± 6.9%, respectively. The mean CCT and ECD values for each group were lower than those for the CG. A significant negative correlation was found between CCT and ECD for AHI values (r = -0.390, P = 0.011 and r = -0.109, P = 0.040, respectively), and a weak positive correlation between CCT and ECD was found for min. SpO2 (r = 0.282, P = 0.020 and r = 0.332, P = 0.018, respectively). CV and HEX did not significantly differ between the groups and did not correlate with the results of polysomnography.

CONCLUSIONS

Hypoxia is associated with significant changes in CCT and ECD. In patients with OSA, these parameters varied significantly when compared with the subjects in the CG. The severity of hypoxemia and the increase in AHI values reduce CCT and ECD in patients.

[Floppy eyelid syndrome : A frequently underdiagnosed entity of interdisciplinary importance]

Clinically, the floppy eyelid syndrome is a frequent but underdiagnosed condition. This clinical phenotype is characterized by an extreme laxity of the eyelid, which is enlarged and has a rubber-like structure in combination with a pronounced hyperelastic tarsus. When looking down, minimal vertical tension can trigger spontaneous eversion of the upper eyelid leading to chronic papillary conjunctivitis. This syndrome usually affects older, adipose men who also suffer from sleep apnea and metabolic syndrome. Due to the resistance of chronic papillary conjunctivitis to conservative treatment, surgical treatment is often necessary; however, due to the frequent association between floppy eyelid syndrome, sleep apnea and metabolic syndrome a collaborative interdisciplinary approach is necessary.

Floppy eyelid syndrome: A comprehensive review

Floppy eyelid syndrome (FES) is defined as eyelid hyperlaxity with reactive palpebral conjunctivitis. It is a common condition that can be associated with significant ocular irritation. FES presents with easily everted eyelids and chronic papillary conjunctivitis in the upper eyelids. It is frequently associated with ocular and systemic diseases, notably keratoconus and obstructive sleep apnea, respectively. This comprehensive review describes the epidemiology, pathological changes, proposed pathogenesis, clinical manifestations, and a variety of treatment options for this condition. Conservative treatment of FES includes aggressive lubrication, nighttime eye shield, and avoiding sleeping on the affected eye. Patients with FES and obstructive sleep apnea may have an improvement in their ocular signs and symptoms after long-term therapy with continuous positive airway pressure. In refractory cases, a corrective surgery that addresses the eyelid laxity can result in significant improvement. All patients with ocular irritation should be evaluated for the presence of FES.

Ocular surface assessment and morphological alterations in meibomian glands with meibography in obstructive sleep apnea Syndrome

PURPOSE

To evaluate ocular surface and Meibomian glands morphology of patients with obstructive sleep apnea syndrome (OSAS).

MATERIALS AND METHODS

Based on polysomnography, 36 eyes of 36 patients with severe OSAS (Group 1, apnea-hypopnea index (AHI) ≥30/h) and 24 eyes of 24 patients with primary snoring or mild OSAS (Group 2, AHI<15/h) were enrolled. Detailed eye examination along with ocular surface staining (fluorescein, 2%) according to Oxford scale, tear film break-up time (t-BUT), Schirmer 1 test, ocular surface disease index (OSDI) scoring, and evaluation of upper and lower eyelid Meibomian glands using infrared filter of slit-lamp biomicroscope were performed. In addition to grading Meibomian gland drop-out, the presence morphologic alterations such as Meibomian gland duct distortion, thinning and dilatation were also assessed.

RESULTS

The mean ages were 50.8 ± 8.3 (range, 35-68) and 47.9 ± 10.5 (range, 27-69) in Group 1 and Group 2, respectively (p = 0.616). Best-corrected visual acuity, Schirmer 1 test, Oxford scale and OSDI scores, and lower meiboscores did not differ significantly between groups. In Group 1, average t-BUT was lower (p = 0.003), upper and total (upper + lower) meiboscores were higher as compared to Group 2 (p < 0.05). The frequency of Meibomian gland duct distortion, thinning and dilatation were also significantly greater in Group 1 (p < 0.05).

CONCLUSION

Morphological changes, in addition to Meibomian glands dropout were significant in severe OSAS patients as demonstrated objectively with meibography. Schirmer 1 and t-BUT tests were in favor of evaporative type dry eye syndrome, which also support Meibomian gland alterations in severe OSAS patients.

Floppy eyelid syndrome "plasty" procedure: Employment of a periosteal transposition flap for surgery of floppy eyelid syndrome

IMPORTANCE

Floppy eyelid syndrome "plasty" (FESplasty) is a surgical technique that addresses underlying superior tarsal plate and lateral canthal instability in floppy eyelid syndrome (FES) and aims to restore normal anatomical and physiological function to the upper eyelid.

BACKGROUND

To describe the use of FESplasty in the surgical management of FES, and to report outcomes in an initial patient cohort.

DESIGN

Retrospective study.

PARTICIPANTS

Seven patients (nine eyelids) with FES undergoing FESplasty.

METHODS

A single surgeon (G.W.) performed all procedures. FESplasty utilizes a periosteal flap based at the inferolateral orbital rim, and applied to the anterior surface of the upper tarsal plate. It is combined with a titrated shortening procedure of the upper eyelid. Patient demographics, comorbidities and ocular symptoms and signs were recorded preoperatively. Pre- and postoperative upper eyelid distractibility were graded and documented.

MAIN OUTCOME MEASURES

Postoperative improvement in upper eyelid distractibility and symptomatology, operative complications and FES recurrence.

RESULTS

FES symptoms and upper eyelid laxity improved at last follow-up (average 24 weeks) in all patients, with no FES recurrences after a maximum follow-up of 36 weeks. One patient, in whom FESplasty exacerbated his pre-existing aponeurotic ptosis, required definitive ptosis surgery subsequently. There was one case of postoperative wound infection. Obstructive sleep apnoea was present in four of the seven patients. The remaining three patients were awaiting assessment.

CONCLUSIONS AND RELEVANCE

FESplasty is likely to confer long-term effective stabilization of the lateral canthal tendon, lateral commissure and superior tarsal plate. Anatomical and functional results appeared to have been successfully achieved.

Assessment of physiological upper eyelid laxity

PURPOSE

To evaluate overall upper eyelid laxity according to age and sleep position.

METHODS

This single-center prospective study was conducted on healthy subjects between 20 and 89 years of age and was approved by the institutional review board and the ethics committee. Data collected were age, sex, weight and height, ophthalmological history, general history (diabetes, hypertension, smoking) and preferred sleep position (lateral, ventral, dorsal decubitus or no preference). Overall upper eyelid laxity was measured using the McNab technique.

RESULTS

In total, 280 patients were included in the study - 40 per 10-year age bracket. Mean overall right eyelid laxity was measured at 5.35mm (5.38mm on the left) between 20 and 29 years old and 8.28mm (8.43mm on the left) between 80 and 89 years old. 161 patients slept in a lateral decubitus position. Median overall upper eyelid laxity for the sleep side was 8mm vs. 7mm for the non-sleep side.

CONCLUSION

Overall upper eyelid laxity increased significantly with age (P<0.001) and compared to the contralateral side (P<0.001). Overall upper eyelid hyperlaxity can be defined as a measurement (by the McNab technique) greater than: 7mm between 20 and 29 years, 8mm between 30 and 39 years, 9mm between 40 and 69 years and 10mm between 70 and 89 years. This study provides new data on normal eyelid laxity in the general population according to age and sleep position.

Obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is increasing in prevalence due to rising obesity. While OSA is a disorder primarily of the upper airway during sleep, its pathophysiological impact on other body systems is increasingly recognised. There has been interest in the prevalence of OSA in different ophthalmic conditions and possible causation has been postulated. As OSA is common, it can be expected that people with co-existent OSA will be found in any ophthalmic disease population studied. To determine with confidence the significance of finding patients with OSA in a particular cohort requires a well matched control group, ideally matched for age, obesity, gender and co-morbidities. Only if one can say with certainty that the prevalence of OSA is higher in a group with a particular co-existent ophthalmic disease can we begin to speculate about possible mechanisms for the overlap in these conditions. Possible mechanisms for how OSA might affect the eye are discussed in this review. The current literature is reviewed with respect to diabetic retinopathy, glaucoma, floppy eyelid syndrome, non-arteritic ischaemic optic neuropathy, keratoconus and AMD. Associations with OSA have been found, but robust prospective studies using multi-channel sleep studies to diagnose OSA are lacking. Gaps remain in the evidence and in our knowledge. It is hoped that this review will highlight the need for ophthalmologists to consider OSA in their patients. It also makes recommendations for future research, especially to consider whether therapies for OSA can also be effective for ophthalmic disorders.

Association between obstructive sleep apnea and optic neuropathy: a Taiwanese population-based cohort study

PURPOSE

Obstructive sleep apnea (OSA) is associated with many systemic diseases including diabetes, hypertension, stroke, and cardiovascular disease. The aim of our study was to investigate the association between OSA and optic neuropathy (ON), and to evaluate the efficacy of treatment for OSA on the risk of ON.

METHODS

We used the data from the Longitudinal Health Insurance Database, which involved one million insurants from Taiwan National Health Insurance program (Taiwan NHI).

RESULTS

OSA patients had a 1.95-fold higher risk of ON compared with non-OSA patients in all age group. The risk was significantly higher (adjusted hazard ratio: 4.21) in the group aged <45 years and male individuals (adjusted hazard ratio: 1.93). Meanwhile, sleep apnea was associated with ON regardless of the existence of comorbidity or not. OSA patients treated with continuous positive airway pressure (CPAP) had an adjusted 2.31-fold higher hazard of developing ON compared to controls, and those without any treatment had an adjusted 1.82-fold higher hazard of developing ON compared to controls. Moreover, ON patients had a 1.45-fold higher risk of OSA, and those aged between 45 and 64 years (hazard ratio: 1.76) and male individuals (hazard ratio: 1.55) had highest risk.

CONCLUSIONS

Our study showed that OSA increased the risk of developing ON after controlling the comorbidities; however, treatment with CPAP did not reduce the risk of ON. Further large population study accessing to medical records about the severity of OSA and treatment for OSA is needed to clarify the efficacy of treatment for OSA in reducing the risk of ON.

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.

Ocular Manifestations of Obstructive Sleep Apnea

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) incurs a host of systemic side effects. The eyes are particularly susceptible to both mechanical and vascular sequelae of the disease. This paper outlines the ocular manifestations of sleep apnea. The authors hope to increase awareness of the ocular complications of this common disorder and increase communication and co-management between eye-care providers and sleep specialists alike.

METHODS

Data were collected from PubMed and the Brown University Library Collection.

RESULTS

Twenty-two papers were included in this review to address floppy eyelid syndrome, nonarteritic anterior ischemic optic neuropathy, central serous retinopathy, retinal vein occlusion, and glaucoma. We used three meta-analyses and several cross-sectional cohort and case-control studies that investigate the aforementioned conditions and their associations with OSA.

CONCLUSIONS

Hypoxia induced by nightly cessation of breathing increases patients' risk of coronary artery disease, heart failure, stroke, and other conditions. As with many maladies detrimental to vascular health, obstructive sleep apnea affects the eye and ocular adnexa. This paper summarizes the current evidence implicating OSA in these ocular maladies and highlights their proposed mechanisms. The authors describe ocular pathology which sleep specialists may encounter. We encourage more aggressive attention to ocular symptoms in patients with sleep apnea to prevent vision-threatening complications. Further research should investigate how sleep apnea treatment affects these ocular findings and identify which sleep apnea patients are most prone to developing ocular pathology.

Repercusiones oftalmológicas del síndrome de apnea-hipopnea obstructiva del sueño (SAHOS)

Las manifestaciones oftalmológicas que se relacionan con el síndrome de apnea-hipopnea obstructiva del sueño (SAHOS) incluyen síndrome de párpado flácido y cambios a nivel del nervio óptico asociados con glaucoma, así como neuropatía óptica isquémica anterior no arterítica y papiledema. La prevalencia del síndrome de párpado flácido en pacientes con SAHOS varía entre 2.3% y 32.6%, mientras que de la asociación entre glaucoma y SAHOS oscila entre 2% y 27%.En la población estudiada en Colombia se encuentra una frecuencia de 2.7% de asociación entre glaucoma de presión normal y SAHOS. El glaucoma presente en estos casos es el primario de ángulo abierto, que bien puede cursar con o sin un aumento de la presión intraocular. En cuanto a la neuropatía óptica isquémica y el papiledema, no se dispone de datos acerca de su prevalencia en pacientes con SAHOS. Se recomienda la valoración por oftalmología a los pacientes diagnosticados con este síndrome.

Diseases of the retina and the optic nerve associated with obstructive sleep apnea

Many associations between ocular disorders and obstructive sleep apnea (OSA) have been studied, such as nonarteritic anterior ischemic optic neuropathy, glaucoma, papilledema, retinal vein occlusion, eyelid hyperlaxity, lower-eyelid ectropion and recurrent corneal erosions. The objective of this review is to synthetize the possible vascular disorders of the retina and the optic nerve associated with sleep apnea patients and to discuss the underlying pathophysiological hypotheses. Main mechanisms involved in the ocular complications of OSA are related to intermittent hypoxia, sympathetic system activation, oxidant stress, and deleterious effects of endothelin 1. The main evidence-based medicine data suggest that OSA should be screened in patients with ischemic optic neuropathy and diabetic retinopathy. The effect of OSA treatment and emerging therapies are discussed.

Evaluation of Ocular Surface Health in Patients with Obstructive Sleep Apnea Syndrome

Objectives:

To evaluate ocular surface health in obstructive sleep apnea syndrome (OSAS) and to investigate the tendency of these patients toward dry eyes.

Materials and Methods:

Fifty patients who underwent polysomnography and were diagnosed with OSAS and 50 normal control subjects were compared with respect to ocular surface disease index (OSDI), Schirmer I test and tear film break-up time (TBUT) values.

Results:

Patients were grouped as mild (n=15, 30%), moderate (n=15, 30%) and severe (n=20, 40%) according to apnea-hypopnea index values. The right eyes of patients were included in both groups. OSDI values were as follows: control group, 18.7±8.5; mild OSAS group, 40.2±2.8; moderate OSAS group, 48.5±2.2 and severe OSAS group, 62.7±2.3 (p<0.001). TBUT values were as follows: control group, 12.3±4.9; mild OSAS group, 8.2±4.7; moderate OSAS group, 5.8±2.1 and severe OSAS group, 4.2±3.7 (p<0.001). Schirmer values were as follows: control group, 18±6.1 mm; mild OSAS group, 12.9±6.7 mm; moderate OSAS group, 8.5±5.2 mm and severe OSAS group, 7.9±4.7 mm (p<0.001).

Conclusion:

Patients with OSAS seem to have a tendency toward dry eyes. Clinicians should be aware of dry eye development in these patients.

Is Floppy Eyelid Syndrome More Prevalent in Obstructive Sleep Apnea Syndrome Patients?

Controversial findings are reported about the relationship between floppy eyelid syndrome (FES) and obstructive sleep apnea syndrome (OSAS). The main goal of this study was to evaluate whether FES is more prevalent in OSAS patients by performing a meta-analysis. A comprehensive literature search of Pubmed, Embase, and Cochrane databases was performed. Only studies related to the prevalence of FES in OSAS were included in the meta-analysis. We estimated a pooled odds ratio (OR) for the prevalence of FES in OSAS. In total, 6 studies with 767 participants met the inclusion criteria. Using a fixed-effects model, the pooled OR was 4.12. The test for the overall effect revealed that FES was statistically prevalent in OSAS patients when compared with that in non-OSAS subjects (Z = 4.98, p < 0.00001). In the subgroup analysis by OSAS severity, the incidence of FES in OSAS increased with severity of OSAS as indicated with increased OR values (OR = 2.56, 4.62, and 7.64 for mild, moderate, and severe OSAS). In conclusion, the results indicate that FES is more prevalent in OSAS patients. However, this result was based only on unadjusted estimates. Prospective cohort studies are needed to determine whether OSAS is an independent risk factor for FES.

The association between ophthalmologic diseases and obstructive sleep apnea: a systematic review and meta-analysis

PURPOSE

The purpose of this study was to evaluate the association between obstructive sleep apnea (OSA) and ophthalmologic diseases, specifically glaucoma, nonarteritic anterior ischemic optic neuropathy (NAION), retinal vein occlusion (RVO), central serous chorioretinopathy (CSR), and floppy eyelid syndrome (FES), by performing a systematic review and meta-analysis of published studies.

METHODS

PubMed, Embase, and Scopus databases were searched for observational studies on OSA and its association with select ophthalmologic diseases. Data was pooled for random-effects modeling. The association between OSA and ophthalmologic diseases was summarized using an estimated pooled odds ratio with a 95 % confidence interval.

RESULTS

Relative to non-OSA subjects, OSA subjects have increased odds of diagnosis with glaucoma (pooled odds ratio (OR) = 1.242; P < 0.001) and floppy eyelids syndrome (pooled OR = 4.157; P < 0.001). In reverse, the overall pooled OR for OSA was 1.746 (P = 0.002) in the glaucoma group, 3.126 (P = 0.000) in the NAION group, and 2.019 (P = 0.028) in the CSR group. For RVO, one study with 5965 OSA patients and 29,669 controls demonstrated a 1.94-fold odds increase in OSA patients.

CONCLUSIONS

Our results suggest significant associations between OSA and glaucoma, NAION, CSR, and FES. Screening for OSA should be considered in patients with glaucoma, NAION, CSR, or FES.

Meta-Analysis of Association of Obstructive Sleep Apnea With Glaucoma

OBJECTIVES

Previous studies suggested that obstructive sleep apnea (OSA) was associated with glaucoma. However, data on this issue are controversial. This study aims to use meta-analysis to determine whether OSA is related to glaucoma.

MATERIALS AND METHODS

We searched PubMed, Embase, the Cochrane library, the Web of Science, and the Chinese BioMedical Literature Database disk databases up to November 20, 2014 for related literature. The association of OSA with glaucoma was assessed by odds ratio (OR) with 95% confidence interval (CI) as the effect size. Then subgroup analysis was performed according to area and glaucoma type.

RESULTS

Six primary studies (3 cohort study and 3 case-control studies) were included in this meta-analysis involving 2,288,701 participants. There was a significant association between OSA and glaucoma (adjusted-effect summary for case-control studies OR=2.46; 95% CI, 1.32-4.59, P=0.005) (adjusted-effect summary for cohort studies OR=1.43; 95% CI, 1.21-1.69, P=0.000). There was no significant publication bias.

CONCLUSION

OSA was a risk factor for glaucoma. A large number of studies is needed to explore the mechanisms that link OSA with glaucoma.

Optic Nerve Dysfunction in Obstructive Sleep Apnea: An Electrophysiological Study

STUDY OBJECTIVES

The aim of this study was to evaluate the integrity of the visual system in patients affected by obstructive sleep apnea (OSA) by means of electroretinogram (ERG) and visual evoked potential (VEP).

METHODS

We performed electrophysiological study of the visual system in a population of severe OSA (apnea-hypopnea events/time in bed ≥ 30/h) patients without medical comorbidities compared to a group of healthy controls similar for age, sex, and body mass index. Patients and controls did not have visual impairment or systemic disorders with known influence on the visual system. ERG and VEP were elicited by a reversal pattern generated on a television monitor at low (55') and high (15') spatial frequencies stimulation. Daytime sleepiness was assessed using the Epworth Sleepiness Scale (ESS) in both patients and controls.

RESULTS

In comparison with healthy controls (n = 27), patients with OSA (n = 27) showed a significant latency delay coupled with a significant amplitude reduction of P100 wave of VEP at all spatial frequencies in both eyes. No significant differences between groups were detected as concerning ERG components. No correlations were found between polygraphic parameters, ESS scores, or VEP and ERG components in OSA patients.

CONCLUSIONS

This study documented that patients with OSA, without medical comorbidities, present VEP alteration as documented by lower amplitude and longer latency of the P100 component than healthy controls. These altered electrophysiological findings may be the expression of optic nerve dysfunction provoked by hypoxia, acidosis, hypercarbia and airway obstruction, frequently observed in patients with OSA. Hence, we hypothesize that OSA per se may impair optic nerve function.

Effect of obstructive sleep apnea syndrome on corneal thickness

Obstructive sleep apnea syndrome (OSAS) might be a risk factor for the development of eye disorders. The aim of the study was to evaluate the effect of OSAS on central corneal thickness (CCT). A total of 195 patients were enrolled in the study, and underwent polysomnography. Patients were divided according to their apnea-hypopnea index (AHI) scores into control group (AHI < 5), mild (AHI, 5-15), moderate (AHI, 15-30), and severe OSAS (AHI > 30) groups. In ophthalmological examinations, CCT, auto refractometer measurement, tear break-up time, and Schrimer's test results were evaluated. Central corneal thickness was significantly decreased in patients with OSAS compared to the control group (542.14 ± 31.21 vs. 569.92 ± 13.46, p < 0.001). As the severity of OSAS increased, CCT decreased (mild OSAS = 567.48 ± 23 mm, moderate OSAS = 530.21 ± 30.2 mm, and severe OSAS = 557.97 ± 16.52 mm, respectively, p < 0.001). The mean values of auto refractometer, tear break-up time, and Schrimer's test were similar between the groups (p > 0.05). CCT was negatively correlated with AHI, oxygen desaturation index, desaturation percentages, and positively correlated with minimum oxygen saturation values (p < 0.05). This study showed that central corneal thickness is inversely correlated with the severity of OSAS. OSAS affects all organ systems particularly cardiovascular and neurological mechanisms. Further studies are warranted to evaluate the effect of OSAS treatment on CCT.

Long-term effects of PAP on ocular surface in obstructive sleep apnea syndrome

OBJECTIVE

To assess the long-term effects of positive airway pressure (PAP) therapy on the ocular surface and eyelid in patients with obstructive sleep apnea hypopnea syndrome (OSAHS).

DESIGN

Single-centred, prospective, and double-blinded study.

PARTICIPANTS

Fifty-one patients with OSAHS.

METHODS

Fifty-one patients with OSAHS were treated with PAP for a period of 18 months. The pre- and post-PAP values for eye examination scores (presence of floppy eyelid syndrome [FES], results of the Ocular Surface Disease Index [OSDI] questionnaire, Schirmer I test, tear film break-up time [TBUT] values, and corneal staining stages) were compared.

RESULTS

Based on the apnea-hypopnea index, 17 patients were followed with moderate and 34 patients were followed with severe OSAHS. The presence of FES before and after PAP was 56.9% and 74.5% (p < 0.01). FES stage was determined as 1.41 ± 0.98 before PAP and 0.78 ± 0.78 after PAP (p < 0.01). Pre-PAP and post-PAP OSDI results were 47.79 ± 21.04 and 42.17 ± 19.97, respectively (p < 0.01). Schirmer values before and after PAP were 7.23 ± 1.95 and 8.49 ± 1.79 mm, respectively (p < 0.01). TBUT values before and after PAP were 7.11 ± 1.82 and 8.68 ± 1.76 seconds, respectively (p < 0.01). Scores of the corneal staining stages before and after PAP were 1.05 ± 0.75 and 0.68 ± 0.54, respectively (p < 0.01).

CONCLUSIONS

OSAHS is associated with low Schirmer and TBUT values, and high scores in OSDI questionnaire, and high corneal staining stage. An appropriate PAP therapy helps to relieve both the systemic findings and the ocular surface problems most likely by providing a return to normal sleep patterns. We believe that long-term (at least 1 year) use of PAP improves the clinical picture of FES and can overcome the problem of ocular irritation that is encountered in the early stage of PAP.

Obstructive sleep apnea and other sleep-related syndromes

Obstructive sleep apnea syndrome (OSAS) is a common disorder characterized by repetitive episodes of breathing cessation due to complete or partial collapse of the upper airway therefore affecting ventilation. It is quite common, with a prevalence of about 2-4%, has a strong genetic component, and creates a proinflammatory state with elevated TNFα and other cytokines. If untreated, OSA can lead to significant neurological problems that include stroke, cognitive decline, depression, headaches, peripheral neuropathy, and nonarteritic ischemic optic neuropathy (NAION). Treatment reverses some of these neurological problems. Treatment includes continuous positive airway pressure and its variants, oral appliances, weight loss, upper airway surgery, and rarely maxillofacial procedures. Other sleep breathing disorders such as hypoventilation, central sleep apnea, complex sleep apnea, and Cheyne-Stokes respiration are less common and are sometimes associated with neuromuscular disorders causing diaphragmatic paralysis, but can also be seen in opiate exposure and severe obesity.

Changes in the circadian rhythm in patients with primary glaucoma

Purpose

The current study was undertaken to investigate whether glaucoma affects the sleep quality and whether there is any difference between patients with primary glaucoma (primary open angle glaucoma, POAG and primary angle-closure glaucoma, PACG) and healthy subjects, using a validated self-rated questionnaire, the Pittsburgh Sleep Quality Index (PSQI).

Methods

The sleep quality of patients with POAG and PACG was tested against normal controls. Subjects were divided into three sub-groups according to age. Differences in the frequency of sleep disturbances (PSQI score >7) were assessed. The differences of sleep quality within the three groups and within the POAG group depending on the patients’ intraocular pressure (IOP) and impairment of visual field (VF) were also studied.

Results

92 POAG patients, 48 PACG patients and 199 controls were included. Sleep quality declined with age in control and POAG group (tendency chi-square, P<0.05). The prevalence of sleep disturbances was higher in POAG and PACG group than in the control group, the differences were statistically significant. The prevalence of sleep disturbances was higher in patients with PACG, compared to POAG patients in the age interval of 61–80. In POAG group, the ratio of patients with sleep disorders increased with augmented impairment of VF, but the differences were not statistically significant (χ²-test, P>0.05). No significant differences were found in POAG group between patients with a highest IOP in daytime and at nighttime (χ²-test, P>0.05).

Conclusions

The prevalence of sleep disorders was higher in patients with POAG and PACG than in controls. PACG patients seemed to have a more serious problem of sleep disorders than POAG patients between 61 to 80 years old. No correlation was found between the prevalence of sleep disorders and impairment of VF or the time when POAG patients showed a highest IOP.

The effect of continuous positive airway pressure treatment for obstructive sleep apnea syndrome on the ocular surface

PURPOSE

To evaluate the effect of continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea syndrome on the ocular surface.

METHODS

This is a prospective, sectional cohort study of 80 eyes of 40 patients diagnosed with obstructive sleep apnea syndrome. Routine ophthalmologic examination and ocular surface evaluation, including biomicroscopy, Schirmer 1 testing, tear break-up time measurement, ocular surface staining, and conjunctival impression cytology, were performed in both of each patient's eyes before and 4 months after starting CPAP therapy.

RESULTS

After CPAP therapy, increases in squamous metaplasia (Nelson classification: t = 0.34, P = 0.014) and Schirmer 1 score (t = 3.20, P = 0.008), and decreases in tear break-up time (t = -1.38, P = 0.008) in the right eyes were statistically significant, as compared with the pretreatment values. Although these parameters changed in a similar fashion in the left eyes, differences between the pre-CPAP and post-CPAP values were not significant.

CONCLUSIONS

The findings indicate that CPAP therapy increased ocular irritation, tear evaporation, and squamous metaplasia in the conjunctiva of the patients' right and left eyes. Although the parameters measured were similar in both eyes before CPAP therapy, these parameters changed significantly after CPAP therapy only in the right eyes. The observed differences between the right and left eyes require further investigation to determine the possible effects of sleeping position, CPAP mask displacement, and the other factors involved.