Changes of individual retinal layer thickness post-uneventful cataract surgery determined by spectral-domain optical coherence tomography over a 3-months period

Abstract

Purpose: To evaluate retinal thickness changes of individual retinal layers using spectral-domain optical coherence tomography (SD-OCT) after uneventful cataract surgery over a 3-months period.

Design: Prospective cohort study.

Methods: 41 patients who underwent uneventful cataract surgery were included. Retinal SD-OCT images of both eyes were acquired preoperatively, 1 day after surgery as well as 1 month and 3 months postoperatively. Changes of retinal layer thickness were estimated after semi-automated segmentation for the following individual layers in the central subfield (CS, 1 mm) and inner ring (IR, 1-3 mm) of the early treatment diabetic retinopathy study (ETDRS) grid: retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), RNFL-GCL-IPL complex, inner nuclear layer (INL), outer plexiform layer (OPL), INL-OPL complex, outer nuclear layer (ONL), inner retina layer (IRL) and the total retina (TR). Furthermore, a sub-analysis with exclusion of patients devoid CME and an analysis in regard of patient age, lens status of the fellow eye, best corrected visual acuity and duration of surgery was conducted.

Results: This study found significant alterations in all analysed retinal layers except for the RNFL (p = 0.33) and the GCL (p = 0.06) in the central subfield and the INL-OPL complex (p = 0.07) in the inner ring over the 3-months period (all p < 0.05). Retinal thickness decreases on the first postoperative day, followed by a significant increase 1 month after surgery and subsequent reduction at 3 months following uneventful cataract surgery could be observed.

Conclusion: These results assume the hypothesis that the apex of inflammatory response, characterized by an augmentation in the thickness of individual retinal layers, occurs around 1 month after uneventful cataract surgery, and subsequently experience a reduction in activity. Therefore, we suggest that additional therapy for cystoid macular edema does not have to be initiated as early as the first month in mild cases.

Fig. 1

Boundaries of segmented retinal layers on spectral domain optical coherence. The segmented boundaries in order from top to bottom are: Internal Limiting Membrane (ILM); Retinal Nerve Fiber Layer (RNFL) outer border; Ganglion Cell Layer (GCL) outer border; Inner Plexiform Layer (IPL) outer border; Inner Nuclear Layer (INL) outer border; Outer Plexiform Layer (OPL) outer border; External Limiting Membrane (ELM) and Bruch's membrane.