LASIK (Laser-Assisted In Situ Keratomileusis) is a common refractive procedure that reshapes the cornea to correct vision, offering an alternative to glasses or contact lenses. Glaucoma is a progressive eye disease characterized by damage to the optic nerve, typically resulting from elevated intraocular pressure (IOP). The mechanics of the LASIK procedure directly interfere with standard methods used to diagnose and monitor glaucoma. Proceeding with LASIK when a patient has glaucoma or is susceptible to it introduces complications that can mask disease progression.
How LASIK Procedures Affect Glaucoma Risk Factors
The primary concern regarding LASIK in a patient with glaucoma is the permanent alteration of the cornea, which affects the accuracy of post-operative IOP measurements. Glaucoma monitoring relies heavily on precise IOP readings, but the thinning of the cornea during the LASIK ablation process causes the standard measurement device, the Goldmann applanation tonometer, to record an artificially low pressure. This underestimation can mask true IOP elevation, delaying diagnosis or treatment of progressing glaucoma, which may lead to irreversible optic nerve damage.
A second, acute risk occurs during the procedure itself with the application of the suction ring required to create the corneal flap. This ring stabilizes the eye but temporarily spikes the intraocular pressure to extremely high levels (60 to 100 mmHg). While this pressure spike is brief, it can be poorly tolerated by an already compromised optic nerve, potentially causing new or accelerated damage. The use of steroid eye drops post-LASIK is another risk factor, as these drops can cause a temporary, yet significant, rise in IOP in certain individuals, which is especially concerning for glaucoma patients.
Determining Suitability: Who Can and Cannot Get LASIK
The decision to proceed with LASIK in a patient with glaucoma or glaucoma risk is complex. Glaucoma is considered a relative contraindication, meaning the procedure is not automatically ruled out but requires intensive individual assessment. Patients with moderate to advanced glaucoma, or those with uncontrolled intraocular pressure, are generally considered unsuitable candidates for LASIK. The risks associated with the procedural pressure spike and the challenges of post-operative monitoring outweigh the benefits of vision correction in these cases.
However, LASIK may be conditionally considered for individuals classified as “glaucoma suspects” or those with very mild, stable, and well-controlled early-stage glaucoma. Glaucoma suspects are patients who exhibit risk factors, such as ocular hypertension or a suspicious optic nerve appearance, but show no definitive signs of optic nerve damage or visual field loss. For these patients, the condition must be non-progressing and stable over an extended period, typically a year or more. Any decision to move forward must involve clearance from both the refractive surgeon and the managing glaucoma specialist.
Critical Diagnostic Screening Before Surgery
Any patient with suspected or confirmed glaucoma considering LASIK must undergo a battery of specialized tests to establish a comprehensive baseline.
Central Corneal Thickness (CCT)
CCT is measured using pachymetry, providing a baseline for assessing the biomechanical changes that will occur during LASIK. This measurement is crucial because a thinner cornea is a known risk factor for glaucoma progression and directly influences the accuracy of post-operative IOP readings.
Optic Nerve Imaging
Detailed imaging of the optic nerve and retinal nerve fiber layer is performed using Optical Coherence Tomography (OCT) to detect subtle thinning or damage. This OCT data is used as an objective structural reference point for all future post-operative monitoring, as the optic nerve damage itself is not affected by the LASIK procedure.
Visual Field and IOP Testing
Visual field testing, or perimetry, is necessary to map the patient’s peripheral vision, looking for functional loss that confirms existing optic nerve damage. Multiple IOP measurements should also be taken at various times of the day to check for natural pressure fluctuations, known as diurnal variation, before any surgical intervention is planned.
Alternative Vision Correction Options
When LASIK is deemed too risky due to glaucoma concerns, several effective alternatives exist that do not carry the same degree of procedural complications or monitoring difficulties.
Photorefractive Keratectomy (PRK)
PRK is often preferred over LASIK because it does not involve creating a corneal flap with a suction ring, thus eliminating the temporary, high-pressure spike during the procedure. PRK still reshapes the corneal surface, but it is considered a safer surface ablation technique for patients with a vulnerable optic nerve.
Implantable Collamer Lenses (ICLs)
ICLs are an advantageous alternative because they involve inserting a permanent lens into the eye without removing any corneal tissue. This procedure leaves the corneal structure entirely intact, meaning the accuracy of post-operative IOP measurements is not compromised.
Refractive Lens Exchange (RLE)
RLE is another lens-based option that involves replacing the eye’s natural lens with an artificial intraocular lens, a procedure similar to cataract surgery. RLE is particularly suitable for older patients and avoids any alteration of the cornea.