**5.2 Surgical treatment**

*Eyesight and Imaging - Advances and New Perspectives*

• For mild KC • High myopia associated with KC • Intolerance/ discomfort with RGP • Prior to PBCL

for KC patient

• RGP intolerance • Inability to obtain optimal RGP fitting • Poor RGP centering • Reduced wearing time with RGP

• Discomfort or RGP intolerance • Irregular cornea where RGP lens fitting are not possible • (unstable RGP on the eye, popping out

of lens • 3 and 9 o' clock staining with RGP • Corneal scarring

RGP • RGP intolerance • 3 and 9 o' clock staining with RGP • Vascularization with

PBCL • Advanced keratoconus • Corneal scarring • Associated ocular diseases

• All options fail to improve vision • Inability to get an optimum fit with

RGP • First lens of choice

**Indication Advantages Disadvantages**

• First lens of choice for visual improvement • Can correct irregular astigmatism

• Comfort • Stable VA • Delays or obviates the need for keratoplasty

*RGP = Rigid gas permeable, Hybrid lens = rigid lens in the center and a soft skirt in the periphery, PBCL = Piggy back lens (RGP lens sitting on top of a soft contact lens) KC = keratoconus, GPC = giant papillary conjunctivitis,* 

• Comfort • Cannot correct irregular

astigmatism

• Less comfortable than other CLs • Need lens adaptation • Inappropriate fitting can compromise ocular

• May associated with increase keratoconus progression [35]

> corneal edema, neovascularization

• Risk of hypoxia, corneal edema, neovascularization • Punctate keratitis • Difficult handling and maintaining

• Difficult in care regimen (require different removal and insertion

• Contraindicate in corneal edema, acute hydrops, post filtration surgery

technique)

health

• GPC

Comfort • Risk of hypoxia,

Comfort • Lost RGP

**Contact lens types**

Soft/ Soft toric

Hybrid lens

Piggyback lens (PBCL)

Scleral lens

**42**

**Table 2.**

*VA = visual acuity.*

*Contact lens in keratoconus (KC).*

Even though the specialized imaging device can provide grading scheme of keratoconus, for practical purposes, the term "advanced keratoconus" may apply to any cases that have unacceptably poor spectacle distance vision and contact lens intolerance. As the diseases progress, spectacles or contact lens cannot provide acceptable vision. This group of patients requires a surgical management such as Corneal collagen cross-linking (CXL), Intrastromal corneal ring segments (ICRS), and Corneal transplantation to restore vision and/or stabilize progression of diseases.

The special considerations in surgical management of keratoconus are listed in **Table 3**.
