What is involved in myopia (nearsightedness) laser treatment?

Myopia Laser Treatment Overview

Laser vision correction for myopia involves two primary procedures—LASIK (Laser-Assisted In Situ Keratomileusis) and PRK (Photorefractive Keratectomy)—both of which permanently reshape the cornea to correct nearsightedness, with LASIK offering faster visual recovery but PRK demonstrating comparable long-term outcomes and potentially better safety for certain patients. 1

Primary Surgical Techniques

LASIK (Laser-Assisted In Situ Keratomileusis)

Procedure Steps:

• A corneal flap is created using either a femtosecond laser or mechanical microkeratome (femtosecond preferred for recut procedures if needed) 1
• The flap is lifted to expose the underlying stromal bed 1
• Excimer laser ablation reshapes the stromal tissue to correct the refractive error 1
• The flap is repositioned, the interface is irrigated with balanced salt solution, and flap alignment is confirmed 1
• Slit-lamp examination confirms proper flap position and absence of interface debris before discharge 1

Visual Outcomes:

• For low to moderate myopia: 98% (median) achieve uncorrected visual acuity (UCVA) of 20/40 or better 1
• For high myopia: 89% (median) achieve UCVA of 20/40 or better 1
• 92% (median) of eyes achieve within 1.00 D of intended correction 1
• Only 0.6% (median) lose two or more lines of best-corrected visual acuity (BCVA) 1
• At 3 months post-surgery, 99% of military patients and 96% of general population patients achieved binocular UCVA of 20/20 or better 1

Visual Recovery Timeline:

• 88% achieve 20/20 or better at 1 month with wavefront-guided LASIK 1
• Visual rehabilitation is rapid, typically within the first postoperative day 1

PRK (Photorefractive Keratectomy)

Procedure Steps:

• The corneal epithelium is removed mechanically or with dilute alcohol 1
• Excimer laser ablation is performed directly on the stromal surface 1
• Mitomycin-C (0.02% for 15 seconds) is often applied off-label to reduce corneal haze risk, particularly for high corrections or prior corneal surgery 1
• A bandage contact lens is applied until re-epithelialization occurs 1

Visual Outcomes:

• 92% achieve UCVA of 20/40 or better at 12+ months 1
• 86% achieve within 1.00 D of expected correction at 12+ months 1
• For low to moderate myopia: 0-1% lose two or more lines of BCVA at 1 year 1
• For high myopia: 6% lose two or more lines of BCVA 1
• At 6 months, 94% achieve 20/20 or better with wavefront-guided PRK 1

Visual Recovery Timeline:

• Slower than LASIK: only 48% achieve 20/20 or better at 1 month 1
• By 6 months, outcomes match LASIK (94% vs 92% achieving 20/20 or better) 1

Choosing Between LASIK and PRK

LASIK is preferred when:

• Faster visual recovery is essential (occupational requirements) 1
• Patient desires minimal postoperative discomfort 1
• Corneal thickness is adequate for flap creation and ablation 1

PRK is preferred when:

• Corneal thickness is borderline or insufficient for LASIK flap 1
• Patient has high risk for corneal ectasia 2
• Patient engages in contact sports or activities with eye trauma risk 1
• Previous corneal surgery makes flap creation risky 1

Predictability by Degree of Myopia

Low to Moderate Myopia (up to -6.00 D):

• Excellent predictability with both procedures 1
• Minimal regression over 10 years (-0.10 D) with PRK 1
• 96% achieve within 1.00 D of intended correction with LASIK 1

High Myopia (-6.00 to -10.00 D):

• Good but reduced predictability compared to lower myopia 1
• More regression over time (-1.33 D over 10 years with PRK) 1
• 89% achieve UCVA of 20/40 or better with LASIK 1

Extreme Myopia (greater than -10.00 D):

• Consider phakic intraocular lenses as alternative, which demonstrate better safety profile with less BCVA loss 3
• LASIK still achievable but with reduced predictability 1

Long-Term Safety and Stability

10-Year Follow-Up Data:

• 73% of LASIK eyes remain within 1.00 D of expected correction 1
• 54.6% demonstrate improvement in BCVA 1
• Minimal regression occurs, primarily in first year, then stabilizes 1

5-Year Follow-Up Data:

• Minimal but statistically significant regression after 1 year 4
• Corneal endothelial cell loss of 1.2% over 5 years (within physiological age-related range) 4
• No serious vision-threatening complications when inclusion/exclusion criteria are strictly followed 4

Critical Contraindications and Precautions

Absolute Contraindications:

• Uncontrolled dry eye disease 5
• Active corneal inflammation or infection 1
• Progressive corneal ectasia or keratoconus 6

Preoperative Requirements:

• Dry eye must be effectively treated before surgery 5
• Stable refraction without evidence of corneal ectasia 6
• Adequate corneal thickness for planned ablation depth 1, 2

Common Complications and Management

Dry Eye Symptoms:

• 35% develop dry eye symptoms at 3 months post-LASIK 5
• 25% of patients without preoperative dry eye develop new symptoms 5
• Symptoms are most common in first few months and typically subside with time 5
• Patients with preexisting dry eye face substantially higher risk for severe postoperative symptoms 5

Flap-Related Complications (LASIK-specific):

• Interface debris, epithelial ingrowth, microstriae, or macrostriae require slit-lamp evaluation 1
• Flap striae can cause irregular astigmatism and BCVA loss 4
• Most serious LASIK complications are flap-related 1

Corneal Haze (PRK-specific):

• Higher risk with deep ablations for high myopia 1
• Mitomycin-C prophylaxis significantly reduces haze formation 1
• More common in eyes with prior corneal surgery 1

Postoperative Care Protocol

Immediate Postoperative Period:

• Examination within 36 hours to document visual acuity and evaluate cornea with slit-lamp 1
• Topical antibiotics administered 1
• Corticosteroids used short-term 1
• Lubrication typically required 1
• Protective eye shield recommended short-term 1
• Mild to moderate discomfort expected during first postoperative day 1

LASIK-Specific Monitoring:

• Confirm proper flap position, appearance, and absence of interface debris 1
• Evaluate for epithelial irregularity, epithelial ingrowth, interface debris, corneal edema, infiltrates, and striae 1

PRK-Specific Monitoring:

• Bandage contact lens remains until re-epithelialization complete 1
• Monitor for corneal haze development 1
• NSAIDs and oral analgesics for pain management 1

Retreatment Considerations

Retreatment Rates:

• 6.3% for both wavefront-optimized PRK and LASIK 1
• Efficacy and predictability of PRK retreatment are less than primary procedures 1

Risk Factors for Retreatment:

• Older preoperative age 1
• Higher degrees of astigmatism 1
• Hyperopia 1
• Colder operating room temperature 1
• Lack of surgical experience 1