Topographical Central Island-Like Pattern After 24 Hrs of Continuous Intraocular Pressure Monitoring with a Contact Lens Sensor

Abstract

With development of the contact lens sensor (CLS), it has become possible to monitor the intraocular pressure (IOP) for 24 hrs continuously. Wearing of CLS often brings blurred vision with transient aggravation of myopia and changes in corneal shape. The author, a 51-year-old man with myopic astigmatism, wore a CLS for 24 hrs on the right eye, and the fellow eye served as a contra-lateral control eye. After wearing, his corrected visual acuity on the right eye decreased from 20/16 to 20/25 with blurred vision, and subjective spherical power and cylindrical power aggravated. Topographical analysis revealed that the instantaneous power increased on the central cornea but decreased on the mid-peripheral cornea. Differential instantaneous map of pre- and post-wearing CLS showed a specific pattern similar to the central island pattern, which is known as the results of steeper fitting of the orthokeratology lens. A surface imprint was observed on the bulbar conjunctiva, corresponding to the edge of the contact lens. These findings seemed due to orthokeratological effects by the steeper fitting of CLS. All of them resolved within 24 hrs after the removal of the CLS.

Keywords: CLS; central island; contact lens sensor; orthokeratological effects; topography; triggerfish.

Figure 1

Results of IOP. Notes: (A) IOP measured by 24 hr continuous monitoring by the CLS in the right eye. (B) IOP measured by a noncontact tonometer every 3 hrs in the left eye. The IOP did not change markedly in both eyes during 24 hr period.

Figure 2

The topographic map of the axial power and pachymetry before placement of CLS.

Figure 3

The topographic map of the axial power and pachymetry just after removal of CLS after 24 hr continuous monitoring of IOP.

Figure 4

The differential map of the instantaneous power measured at pre-and post-wearing CLS. Note: It showed a specific pattern shaped to resemble central island pattern caused by steeper orthokeratology lens fitting.

Figure 5

Ocular findings of the anterior segment at just placed the CLS and at 1 hr after starting. Notes: (A) CLS on the right eye just after placed. There was no hyperemia. (B) The CLS is fixed with the bulbar conjunctiva and mild bulbar conjunctival hyperemia was shown.

Figure 6

Ocular findings just after removal of the CLS following 24 hr continuous measurement of the IOP. Notes: (A) The bulbar conjunctiva showed obvious hyperemia. (B) Fluorescein staining. The superficial punctate keratitis was shown in superior temporal mid-peripheral (arrowhead) and inferior segment (arrow). (C) Rose Bengal staining. The surface imprint on the bulbar conjunctiva, corresponding to the edge of the CLS was observed (arrow).