10 year follow up of 10 year follow up of LASIK surgery for low LASIK surgery for low

to high levels of to high levels of myopiamyopia

Qasim Qasem FRCS, Caitriona Kirwan MRCOpth, Michael O’Keefe FRCS.

Institutional Affiliations:Mater Private Hospital1, Eccles Street, DublinUniversity College Dublin2, Ireland

Introduction:Introduction:

► LASIK, lamellar flap creation followed by laser LASIK, lamellar flap creation followed by laser ablation, is largely responsible for the popularising ablation, is largely responsible for the popularising of corneal refractive surgery.of corneal refractive surgery.

► Follow up studies are very important for Follow up studies are very important for improvement of treatment algorithms, better improvement of treatment algorithms, better definition of treatment boundaries, management definition of treatment boundaries, management and outcome of early postoperative complications, and outcome of early postoperative complications, monitoring visual acuity results and stability at monitoring visual acuity results and stability at short and long term.short and long term.

Objective:Objective: To evaluate the long term safety and To evaluate the long term safety and

stability of laser in situ keratomileusis stability of laser in situ keratomileusis (LASIK) for the treatment of low to (LASIK) for the treatment of low to high levels of myopiahigh levels of myopia

Methods:Methods:► Out of Ninety patients invited for review after ten years Out of Ninety patients invited for review after ten years

from their refractive laser surgery, forty three patients were from their refractive laser surgery, forty three patients were assessed ( 48 %.) .assessed ( 48 %.) .

► All procedures performed by one surgeon (MOK) by All procedures performed by one surgeon (MOK) by Technolas 117 laser platform (Bausch & Lomb)Technolas 117 laser platform (Bausch & Lomb)

► date of surgery, age at the time of surgery, refractive error date of surgery, age at the time of surgery, refractive error treated, optical zone used, flap thickness, ablation depth, treated, optical zone used, flap thickness, ablation depth, early postoperative complications, visual and refractive early postoperative complications, visual and refractive outcome three months postoperatively and re-treatments outcome three months postoperatively and re-treatments recorded.recorded.

► At ten year follow up of patients ( 74 Eyes) had a full At ten year follow up of patients ( 74 Eyes) had a full ophthalmic assessment, unaided and best corrected visual ophthalmic assessment, unaided and best corrected visual acuity were recorded, current refractive error, Corneal acuity were recorded, current refractive error, Corneal Topography by (Orbscan, Bausch & Lomb), Aberrometry by Topography by (Orbscan, Bausch & Lomb), Aberrometry by (Zywave, Bausch & Lomb), Corneal hysteresis by (Reichert (Zywave, Bausch & Lomb), Corneal hysteresis by (Reichert Ocular Response Analyzer), Contrast sensitivity (Pellie Ocular Response Analyzer), Contrast sensitivity (Pellie Robson), Slit lamp examination & dilated funduscopy.Robson), Slit lamp examination & dilated funduscopy.

► All patients were also questioned regarding any night vision All patients were also questioned regarding any night vision complaints and satisfaction in general.complaints and satisfaction in general.

Results:Results:

► The average age The average age at the time of surgery at the time of surgery was 32.5 was 32.5 with a range between with a range between 20 to 54 years of age.20 to 54 years of age.

► Mean refractive spherical equivalent treated was -5.67 dioptre, with a Mean refractive spherical equivalent treated was -5.67 dioptre, with a range of -1.75 dioptre to -12.5 dioptre, target of treatment was range of -1.75 dioptre to -12.5 dioptre, target of treatment was emmetropia for all patients.emmetropia for all patients.

► Preoperative central corneal thickness average was 557.5 Preoperative central corneal thickness average was 557.5 ±± 46.96 46.96 (microns), with a range between 442 to 670 microns.(microns), with a range between 442 to 670 microns.

► Optical zone of treatment average was 5.8 Optical zone of treatment average was 5.8 ±± 0.4 mm with a range 0.4 mm with a range between 5 to 7 mm.between 5 to 7 mm.

► Depth of ablation range was 50 to 167 micron, with an average of Depth of ablation range was 50 to 167 micron, with an average of 114.9 114.9 ±± 26.4 microns, and average flap thickness was 160.4 micron. 26.4 microns, and average flap thickness was 160.4 micron.

► There was one intra-operative complication of a free flap which was There was one intra-operative complication of a free flap which was managed with no loss of best corrected visual acuity.managed with no loss of best corrected visual acuity.

► Three eyes out of the seventy four had re- treatment at early period Three eyes out of the seventy four had re- treatment at early period within the first year and another two were re-treated within the first within the first year and another two were re-treated within the first five years.five years.

► At ten year follow up further 7 eyes required enhancementAt ten year follow up further 7 eyes required enhancement

Three Months Ten YearsThree Months Ten Years

► ≥ ≥6/6 58.1% 6/6 58.1% 49.2%49.2%

► 6/7.5- 6/9 22.97% 28.9%6/7.5- 6/9 22.97% 28.9%► 6/12 8.10% 8.6%6/12 8.10% 8.6%► 6/15 – 6/24 5.40% 8.6%6/15 – 6/24 5.40% 8.6%► 6/36 – 6/60 5.40% 4.3%6/36 – 6/60 5.40% 4.3%

Three months post treatment Vs 10 Years unaided visual Three months post treatment Vs 10 Years unaided visual acuityacuity

Aberration profileAberration profile::

► All patients had an aberration scan at their ten year visit.All patients had an aberration scan at their ten year visit.► Out of the 43 patients, only eight patients (18.6 %) Out of the 43 patients, only eight patients (18.6 %)

described some degree of difficulties with night vision and described some degree of difficulties with night vision and continued to experience symptoms of glare which was continued to experience symptoms of glare which was confirmed with aberrometry. Majority of patients were confirmed with aberrometry. Majority of patients were asymptomatic even with a level of high order aberrations asymptomatic even with a level of high order aberrations above normal level.above normal level.

► The average high order aberration at 6 mm is 0.84The average high order aberration at 6 mm is 0.84± 0.3± 0.3 microns, the average 4th order spherical aberration is -0.48 microns, the average 4th order spherical aberration is -0.48 ± 0.2 ± 0.2 microns.microns.

► The total level of aberration is higher than 0.80 microns. The total level of aberration is higher than 0.80 microns. (Table 3), (Table 3),

► 19 eyes (27.5%) had HOA at 6mm higher than one, 42 eyes 19 eyes (27.5%) had HOA at 6mm higher than one, 42 eyes (60.8%) between 0.5 and 1.00 micron and the remaining (60.8%) between 0.5 and 1.00 micron and the remaining were below 0.50 microns. (Figure 1)were below 0.50 microns. (Figure 1)

► Figure 1- Zywave Aberrometry Figure 1- Zywave Aberrometry

Higher Order Aberrations

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Total Trefoil Coma Coma Trefoil Spher. x axis x axis y axis y axis aber.

Mic

rons

PredictabilityPredictability

► The percentage of patients within plus or minus 0.5D and plus minus 1.00D of intended The percentage of patients within plus or minus 0.5D and plus minus 1.00D of intended correction.correction.

Within Within ±0.5 D At 3/12 At 10 Yrs Within ±1.0 D At 3/12 ±0.5 D At 3/12 At 10 Yrs Within ±1.0 D At 3/12 At 10 yrsAt 10 yrs

► All levels 45.9% 28.37% 79.73% All levels 45.9% 28.37% 79.73% 58.1% 58.1%

► Low Myopia 57.1% 42.80% 100% Low Myopia 57.1% 42.80% 100% 85.7% 85.7%

► Moderate Mope 58.9% 35.9% 94.8% Moderate Mope 58.9% 35.9% 94.8% 69.23%69.23%

► High Mope 25.0% 14.28 % 53.7% High Mope 25.0% 14.28 % 53.7% 35.71 %35.71 %

Retreated Patients:Retreated Patients:

► MRSE Age at Rx Regression Sex MRSE Age at Rx Regression Sex

► -5.625 D 21 -1.5 D F -5.625 D 21 -1.5 D F

► -7.75 D 45 -2.0 D F -7.75 D 45 -2.0 D F ► ► -7.375 D 41 -3.25 D M -7.375 D 41 -3.25 D M

► -6.00 D 34 -1.75 D F -6.00 D 34 -1.75 D F

► -5.00 D 29 -0.75 D M -5.00 D 29 -0.75 D M

► -6.5o D 34 -1.75 D F -6.5o D 34 -1.75 D F

► -8.75 D 23 -3.35 D F -8.75 D 23 -3.35 D F

► - 5.0 D 30 -1.25 D F - 5.0 D 30 -1.25 D F

► -6.0 D 21 -1.25 D F -6.0 D 21 -1.25 D F

► -5.6 D 21 -1.00 D F -5.6 D 21 -1.00 D F

► -8.5 D 24 -1.75 D F -8.5 D 24 -1.75 D F

► -6.15 D 24 - 1.50 D F-6.15 D 24 - 1.50 D F

ConclusionConclusion

► at ten year follow up, Lasik is a safe procedure at ten year follow up, Lasik is a safe procedure ► however, there was a 15 % regression.however, there was a 15 % regression.► this was mostly in high myopic patients and it seems to this was mostly in high myopic patients and it seems to

be associated with the younger patients.be associated with the younger patients.

RecommendationRecommendation► Patients with high myopia should be informed of the Patients with high myopia should be informed of the

potential to become myopic again and require glasses.potential to become myopic again and require glasses.► Surgeons treating those patients should be aware of Surgeons treating those patients should be aware of

this and perhaps build in the option of further surgical this and perhaps build in the option of further surgical re-treatment as part of their initial surgical approach.re-treatment as part of their initial surgical approach.