# Changes of individual choroidal thickness post-uneventful cataract surgery determined by spectral-domain optical coherence tomography over a 3-month period

## TL;DR

This study found that choroidal thickness and volume increase temporarily after cataract surgery, likely due to inflammation and pressure changes.

## Contribution

The study provides new insights into choroidal structural changes following cataract surgery using EDI-OCT measurements over 3 months.

## Key findings

- Choroidal thickness and volume increased significantly at 1 month post-surgery, then decreased by 3 months.
- Changes were observed in most ETDRS sectors, with no return to baseline levels by month three.
- Postoperative structural changes were similar in patients with and without cystoid macular edema.

## Abstract

To evaluate changes in choroidal thickness and choroidal volume after uncomplicated cataract surgery using enhanced depth imaging optical coherence tomography (EDI-OCT) over a 3-month period.

For this retrospective analysis, data collected in a different, prospective study previously conducted at the Department of Ophthalmology, Medical University of Graz, Austria, was utilized and further analysed. In the original study, retinal layer thickness was measured using spectral-domain optical coherence tomography (SD-OCT) before surgery and at 1 day, 1 month, and 3 months postoperatively. During the current study, the automated segmentation of the retina was manually adjusted to the choroid, using EDI-OCT. Subsequently, choroidal thickness in the central subfield (1 mm) and in the superior, inferior, temporal and nasal sectors of the inner ring (3 mm) as well as choroidal volume of the inner and outer ring (3 mm and 6 mm) of the “early treatment diabetic retinopathy study” (ETDRS) grid were extracted. We included 41 patients who underwent uncomplicated cataract surgery between February 2016 and October 2017. Patients with pre-existing ocular or systemic conditions, intraoperative complications or insufficient image quality were excluded.

A total of 42 eyes of 41 patients (mean age 70.2 ± 8.7 years; 51.2% male) were analysed. In almost all ETDRs sectors, a significant increase in choroidal thickness and volume with a maximum at 1 month postoperatively was found (p ≤ 0.05), followed by a decrease by month three, without returning to baseline levels. Five eyes (11.9%) developed cystoid macular edema. The postoperative pattern of structural changes was comparable in patients with and without cystoid macular edema.

Our results suggest that there are significant changes in choroidal thickness and volume after uncomplicated cataract surgery. The most probable causes are acute inflammatory processes, hemodynamic adjustments to postoperative intraocular pressure fluctuations and metabolic reactions to improved optical transmission.