INTRODUCTION:
Lasik - Laser in situ keratomileusis is by far the predominant
refractive procedure in use today. We are beginning to learn both its full
potential and its limitations. This includes refining our knowledge about
how much refractive error can be corrected with LASIK while maintaining
a high quality of vision.
Laser in situ keratomileusis has become the most popular
refractive procedure performed today because of its safety, efficacy,
quick visual recovery and minimal patient discomfort.
In LASIK, an automated microkeratome is used to create a
corneal flap. The stromal bed is ablated with excimer laser, depending on
the type and amount of refractive error in accordance with the
predetermined data that has been entered in the excimer laser system.
Under this precise control the laser reshapes the curvature of the cornea
to correct myopia, hypermetropia or astigmatism. The flap adheres to the
underlying stroma within 24 hrs. as a result of the endothelial pump.
LASIK is performed on an out patient basis.
The efficacy and success of LASIK depends largely on the type of
laser platform in use. Current fifth generation systems use a very rapidly
repetitive and extremely small spot laser delivery with automated tracking
of the eye movements to ensure precise treatment.
AIM OF THE STUDY: To study the outcome of LASIK performed in patients with mild,
moderate and high myopia using the Mel 80 excimer laser system.
RESULTS: In this prospective, randomised study 37 eyes of 19 patients
belonging to the mild myopia group (-1 D to -6 D). 41 eyes of 23 patients
belonging to the moderate myopia group (-6 D to -12 D) and 18 eyes of
13 patients belonging to high myopia group (> - 12 D) who underwent
lasik between the period August 2005 to June 2006 at Institute of
Ophthalmology, Joseph Eye Hospital, Trichy, were included in the study.
Gender: In mild myopia group there were 5 males and 14 females, In moderate myopia group there were 11 males and 12 females, In high myopia group there were 8 males and 5 females.
Age:
The mean age was 24.5.
The maximum number of patients were in the age group 18-35
years
In mild myopia group 12 patients were in 18 to 25 years age group.
5 patients were in 25 to 35 years age group.
2 patients were in above 35 years age group
In moderate myopia group 14 patients were in 18 to 25 years age group.
6 patients were in 25 to 35 years age group.
3 patients were in above 35 years age group
DISCUSSION: Overall, many reports have shown excellent medical outcome in
terms of predictability, efficacy and safety after lasik. Lasik surgery is still
a controversial issue despite almost 10 years of experience and over 8
million patient treated worldwide.
In our study when comparing the 6 months post surgical
uncorrected vision with the best corrected pre-surgical visual
performance in the 3 groups, patient described themselves as satisfied
with the mean presurgical BCVA being 1 and postoperative mean UCVA
of 1 in low myopia group. Mean BCVA of 1 and post-operative mean
UCVA of 1 in the moderate myopia groupand a mean BCVA of 0.3 and
post-operative UCVA of 0.5 in high myopia. The overall predictability was 100% in the mild and moderate
myopia group and > 80% in high myopia group which is comparable to
the study conducted by Nayyirih G18 and associates.
SUMMARY: In this prospective study 96 eyes of 57 patients underwent LASIK
with Mel 80 Laser system of which 37 eyes were of low myopia, 41 eyes
were of moderate myopia and 18 eyes were of high myopia. Pre-operative UCVA, BCVA, spherical equivalent, topography, corneal thickness, keratometry, pupil diameter were recorded for all the patients. Lasik was done for all the patients in an attempt to achieve the preoperative BCVA. CONCLUSION: The findings in this study, are significant showing good unaided
post-operative visual acuity with excellent safety profile. Overall patient
satisfaction with the procedure is high with the Mel 80 laser system which
is comparable to other fifth generation excimer laser system. The
emergence of better laser nomograms, safer microkeratomes, larger
optical zones, and improved understanding of aberrations and their
significance will lead to improvements in patient outcome in future
