USAEyes Lasik grant application.
How to Choose
A Lasik Doctor
Find Certified Surgeon
50 Tough Lasik Questions
Ask Lasik Expert
Lasik Q&A Forum
Top Articles
What is Lasik?
Lasik Cost
Lasik Results
Wavefront Custom iLasik
Bladeless Lasik
Lasik Patient Survey
Lasik Alternative
Top Articles
Monovision Lasik
PRK, LASEK, Epi-Lasik
RLE Lens Exchange
Lasik Groupon
$1,500 Off Lasik

Image of Lasik doctors certification logo.

This website is accredited by Health On the Net Foundation. Click to verify.   The website complies with the HONcode standard for trustworthy health information: verify here.

Corneal Central Island

Causes and treatment of a central island after Lasik, Bladeless Lasik, PRK, LASEK, or Epi-Lasik.

Topographical map of a central island after Lasik  
An uneven laser ablation can create an irregular corneal surface resulting in a topographical "island" as shown by the central red spot.  

A central Island is a complication of excimer laser assisted refractive surgery that occurs when the laser fails to remove a portion of the cornea in the ablation zone. Light passing through the resulting bump in the cornea bends erratically and presents very poor vision. Visual symptoms of a central island typically include distortion or monocular diplopia.

Central islands are exceedingly rare with current techniques and technology.

Why A Central Island Occurs

A central island tends to occur more often with a broad-beam type laser, when a foreign substance like water or oil inadvertently gets on the corneal bed, or when the plume of escaping cells interferes with subsequent laser pulses. Central islands only occur with conventional or custom wavefront Lasik, Bladeless Lasik, PRK, LASEK, or Epi-Lasik excimer laser assisted procedures. A central island can not occur with lens based refractive surgery procedures like RLE and P-IOL.

Treatment Options

There are many treatment options for a central island and resolution of some degree is highly likely, however a patient with a central island should proceed carefully with any additional wavefront guided laser treatment. Wavefront guided ablation tends to provide limited relief from a central island. A central island is primarily a topography issue, not one of higher order aberrations, which wavefront normally excels at resolving.

A noninvasive technique for central island resolution is the use of contact lenses. A contact lens may "smash down" the central island and create a more uniform surface. If the central island is shallow, a soft contact may resolve the problem. If the central island is significantly elevated, a Rigid Gas Permeable (RGP) contact lens may be the better choice.

A more aggressive technique that may be appropriate to resolve a central island is Contact Lens Assisted Pharmacologically Induced Kerato Steepening (CLAPIKS). We have a detailed article about CLAPIKS including a downloadable white paper for your doctor to review. This is an advanced use of contact lenses and topical eye drops to reshape the cornea.

Depending upon the nature of the central island, a topography-guided flying spot laser ablation may remove the excess tissue and return the cornea to a more regular surface by applying laser energy only to the raised area.

Another topography based treatment for resolution of a central island is Custom Contoured Ablation Pattern (C-CAP). C-CAP is the customization of laser vision correction treatments for central islands and similar corneal aberrations. The FDA has approved use of the C-CAP method with an excimer laser under a Humanitarian Device Exemption (HDE). Procedures under a HDE are medical procedures specially designated by the FDA for the treatment of fewer than 4,000 patients per year with rare medical conditions.

C-CAP uses a liquid material that is applied to the outside of the cornea. In some cases, a contact lens is applied over the liquid to give a smooth surface. The liquid becomes more firm, and the contact (if used) is removed. A broad-beam laser applies energy to the entire treatment area with each pulse. The liquid ablates at the same rate as corneal tissue. As the laser removes tissue or the liquid, the high areas of the cornea are exposed and ablated down to the low areas. C-CAP has been shown to resolve many topographical imperfections caused by disease, trauma, or surgery.

Where To Seek Help

Before a patient with a central island considers any surgery of any kind, it is very highly recommend that the opinion of a corneal specialist, preferably one who is affiliated with a nearby teaching hospital, is obtained. A teaching hospital will commonly provide the greatest level of resources, the second opinion will provide an affirmation that the proposed corrective procedure is appropriate and the peace of mind that the patient is on the right path to recovery.

Recommendations for patients with central islands are:

  • Get a second opinion from a corneal specialist.
  • Use a contact to reshape the cornea, soft or RGP as required.
  • Discuss CLAPIKS with your doctor.
  • Evaluate C-CAP or similar topography-based procedures.

How To Avoid A Central Island

The best way for a patient to avoid a central island is select a doctor who uses current technology and has a proven track record of success. Selecting an evaluated doctor or evaluating a doctor yourself is always wise.

Looking For Best Lasik Surgeon?

If you are ready to choose a doctor to be evaluated for conventional or custom wavefront Lasik, Bladeless Lasik, PRK, or any refractive surgery procedure, we recommend you consider a doctor who has been evaluated and certified by the USAEyes nonprofit organization. Locate a USAEyes Evaluated & Certified Lasik Doctor.

Personalized Answers

If this article did not fully answer your questions, use our free Ask Lasik Expert patient forum.

Recent Corneal Central Island Medical Journal Articles...

Related Articles

Central island treatment using Technolas 217 based on Orbscan II assessment.

J Refract Surg. 2005 May-Jun;21(3):294-6

Authors: Cheng AC, Lam DS

PURPOSE: To present a case of central island after myopic laser in situ keratomileusis and the treatment technique using Technolas 217 laser based on topography findings.
METHODS: Serial corneal topographies with Orbscan were taken and an ablation profile was generated with subsequent treatment using the phototherapeutic keratectomy mode and surface ablation technique.
RESULTS: Marked reduction was noted in the height of central island and the best spectacle-corrected visual acuity improved from 20/40 to 20/25.
CONCLUSIONS: Ablation profile based on corneal topography can provide a possible treatment option for patients with central island.

PMID: 15977888 [PubMed - indexed for MEDLINE]


Last updated

"Consider and Choose With Confidence"TM

A few of the communities where Lasik doctors are certified by USAEyes :