# Effect of Obstructive Sleep Apnea Syndrome on Macular Edema Severity and Response to Intravitreal Ranibizumab in Diabetic Retinopathy and Retinal Vein Occlusion

## TL;DR

This study explores how sleep apnea affects eye swelling and treatment response in patients with diabetic retinopathy or retinal vein occlusion.

## Contribution

The study is novel in evaluating how obstructive sleep apnea severity influences macular edema and ranibizumab treatment outcomes.

## Key findings

- Patients with mild to moderate sleep apnea showed significant visual improvement after ranibizumab treatment.
- Severe sleep apnea was associated with minimal and statistically insignificant visual improvement.
- A weak positive correlation was found between sleep apnea severity indices and central macular thickness.

## Abstract

Background

Obstructive sleep apnea syndrome (OSAS) is a condition characterized by repeated episodes of partial or complete blockage of the upper airway during sleep, leading to disrupted breathing and poor sleep quality. In individuals with OSAS, blood oxygen levels can drop significantly due to repeated interruptions in breathing during sleep. The retina is highly sensitive to oxygen levels, and prolonged hypoxemia can contribute to retinal damage and worsen macular edema.

Objective

The study aims to correlate the effect of OSAS on the severity of macular edema as evaluated through optical coherence tomography (OCT) in patients with diabetic retinopathy and retinal vein occlusion. Additionally, the study seeks to assess treatment outcomes following anti-vascular endothelial growth factor (VEGF) therapy. It will also evaluate the relationship between subfoveal choroidal thickness (SFCT) and OSAS using enhanced depth imaging OCT.

Methods

Patients with macular edema secondary to diabetic retinopathy or retinal vein occlusion were identified through a complete ophthalmological examination and referred to pulmonology for level 1 polysomnography to diagnose concomitant OSAS. All patients received anti-VEGF ranibizumab for macular edema, with monthly follow-ups until the macular edema resolved (central macular thickness (CMT) less than 250 µm) or until three intravitreal ranibizumab injections were administered. All data were collected and analyzed.

Results

The study included 12 participants, with a mean age of 51.33 ± 14.16 years, a mean height of 163.41 ± 7.21 cm, and a mean weight of 65.08 ± 13.31 kg. Among the participants, 25% had mild OSAS, 50% had moderate OSAS, and 25% had severe OSAS. All participants showed improvement in visual acuity when comparing the first and third visits, with a p-value < 0.05 for the mild and moderate OSAS groups. The decline in CMT post-intravitreal ranibizumab was significant across all levels of OSAS, with a p-value < 0.05. The mean SFCT was reduced in all participants relative to normal age-matched controls; however, these results were not statistically significant. A weak positive correlation was observed between the apnea-hypopnea index and CMT, as well as between the oxygen desaturation index and CMT.

Conclusions

The study findings indicate that while there was no significant association between the severity of OSAS and CMT, there was a statistically significant improvement in visual acuity following anti-VEGF injections in patients with mild to moderate OSAS. In cases of severe OSAS, the improvement in vision was minimal and statistically insignificant. Additionally, the mean SFCT was significantly reduced in the study population compared to normal age-matched controls, but no significant differences were found when comparing the different severities of OSAS individually.