Related Experiment Video
Updated: Jul 17, 2026
Three Different Protocols of Corneal Collagen Crosslinking in Keratoconus: Conventional, Accelerated and Iontophoresis
Published on: November 12, 2015
Reduced best spectacle-corrected visual acuity from inserting a thicker Intacs above and thinner Intacs below in
Colin C K Chan1, Brian S Boxer Wachler
1Boxer Wachler Vision Institute, Beverly Hills, Calif, USA.
Purpose:
To report a case of decreased best spectacle-corrected visual acuity (BSCVA) 2 months after Intacs implantation.
Methods:
A 33-year-old woman with keratoconus and contact lens intolerance underwent Intacs surgery in the left eye at another institution. Two segments were used--a thinner one (0.25 mm) below the cone and a thicker one (0.35 mm) above the cone.
Results:
Two months postoperatively, the patient presented to our practice with BSCVA reduced from 20/20 to 20/30. The superior Intacs segment was explanted, the inferior segment was exchanged for a thicker one (0.35 mm), and collagen cross-linking with riboflavin treatment was performed. This resulted in visual, topographic, and refractive improvement with BSCVA returning to 20/20.
Conclusions:
Single inferior segment Intacs may be more appropriate for paracentral and peripheral cones. Collagen cross-linking may help cause further flattening. Using asymmetrical segments, with the thicker segment above the cone, may increase distortions and result in loss of BSCVA.
Related Concept Videos
01:27Open Angle Glaucoma: Treatment
Drugs such as carbonic anhydrase inhibitors, α2- and...
01:28Angle Closure Glaucoma: Treatment
01:16Focusing of Light in the Eye
01:25Glaucoma: Overview