**Conflict of interest**

*Eyesight and Imaging - Advances and New Perspectives*

*and the conjunctival surface in a hybrid contact lens wearer.*

relationship between CL and tears [8, 77].

vision rehabilitation for most of the patients.

**4. Conclusions**

**Figure 3.**

AS-OCT in progressive diseases such as KC. Because, in patients with KC, with the advancement of the cone and the decrease of the Vault, it may cause the touch between the cornea and the lens, corneal scarring and decreased vision. Therefore, the idea (owing to AS-OCT) that lenses can be used for a long time by increasing the vault has emerged in KC patients [54, 72]. The fact that the anterior segment AS-OCT provides in vivo information that cannot be obtained with videokeratoscopy and standard methods in CL applications of KC patients has led to an increasing interest in AS-OCT in CL practitioners. AS-OCT helps to examine the corneal midperiphery, the limbus region, the border structure of CL [73, 74]. Although OCT can also help evaluate scleral curvature, which will be useful in peripheral designs of S-CLs, it is not yet possible to measure scleral shape. OCT also helps to accurately evaluate the interaction between the anterior corneal and conjuctival surface and CL (**Figure 3**). It can measure the central and peripheral tear film clearance under the CL and thus provides information about the fitting [75, 76]. Central and peripheral vaults of hybrid, scleral and miniscleral lenses can also be measured with OCT. This helps us to examine in detail the relationship between asymmetric cornea and CL in KC. With using AS-OCT in CL practice, the maximum central cone vault values required to prevent edema due to hypoxia in the cornea under the scleral lens have been suggested. OCT also plays a major role in defining the

*Anterior segment-optical coherence tomography image showing the interaction between the contact lens corneal* 

Despite current surgical advances in KC treatment, CLs continue to be important for visual rehabilitation (even after surgery) in KC. Advances in CL design and materials have significantly expanded the application area of CL in the KC and ensured that the majority of patients have a satisfactory visual acuity. Thus, the rate of patients undergoing keratoplasty has decreased or the need for keratoplasty has been delayed. Although it takes a lot of time to choose the appropriate lens in KC, most of the patients with KC can benefit from CL use with the new designs and materials developed. CLs offer non-surgical options generally preferred for vision rehabilitation in the KC. SCLs, RGPs, PBCLs, HCLs, S-CLs constitute the contemporary range of lens types available for the vision rehabilitation of KC patients. This wide CL range meets the optometric needs of most of the patients with KC disease today and eliminates the need for major surgical procedures such as keratoplasty for

**72**

The authors declare no conflict of interest.
