**4. Investigations**

### **4.1 Ocular coherence tomography**

Swept-Source Ocular Coherence Tomography (SS-OCT) gives a high-resolution image of the vitreoretinal interface, neurosensory retina, retinal pigment epithelium and choroid. This investigation identifies surrounding epiretinal membrane, the cuff of subretinal fluid and intraretinal cystic change, vitreo-foveal adhesion, operculum or pseudo-operculum and status of RPE. It also allows accurate calculation of various macular hole indices that have a role in giving a prognosis.

## **4.2 Macular hole indices**


Greater MHI and THI are linked to better post-operative functional results. MHI relates to external limiting membrane (ELM) restoration, while MLD and BD are to anatomical closure (**Figure 3**).
