الفهرس 
Aim of the studyOnly 14 pages are availabe for public view
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Abstract
Keratoconus is a bilateral, progressive, non-inflammatory
disease of the cornea which often leads to high myopia and
astigmatism with an estimated prevalence of approximately 1 in 2000.
In the general population, the incidence of keratoconus is estimated to
be between 50 and 230 per 100,000. It seems to be a multifactorial
disease with an unknown exact etiology which impairs the quantity
and quality of vision secondary to thinning in and protrusion of the
cornea. This results in an irregular astigmatism with or without
myopia. Despite the fact that only one eye may be affected initially,
keratoconus ultimately affects both eyes.
The conservative management of keratoconus in early stages
consists of spectacle correction or rigid contact lenses. In more
advanced stages with severe corneal irregular astigmatism and stromal
opacities, surgical treatment with deep lamellar keratoplasty and
penetrating keratoplasty (PK) should be considered.
ICRSs were designed with the goal of delaying or avoiding
corneal grafts in keratoconus patients. It represents a prominent
evolution in the management of keratoconus via flattening the central
corneal curvature to achieve a refractive adjustment due to the
removable and tissue saving nature of the technique.
The high efficiency of Intacs in correcting keratoconic eyes has
been reported by several authors. ICRS implantation in post-Lasik
ectasia appears to be safe and effective in decreasing myopia, corneal
steepness, and decentration of the corneal apex and offers potential
improvement of UCVA and BSCVA in keratoconus patients.
Summary
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The high accuracy cuts to the corneal tissue demonstrated by
femtosecond lasers in refractive surgery have generated new inquiry
on their application into tunnel creation for precision ICRS insertion.
The advantages of femtosecond channel creation over mechanical
approaches are the following: a more uniform dissection is created;
the results and ICRS placement are more consistent; and because it is
minimally invasive, there is less patient discomfort and quicker
recovery.
Information about corneal curvature can be obtained with a
variety of instruments that reflect the images of multiple concentric
circles from the corneal surface. These devices allow analysis of
corneal curvature in zones both central and peripheral to those
measured by keratometry. In general, on steeper parts of the cornea,
the reflected mires appear closer together and thinner and the axis of
the central mire is shorter. Conversely, along the flat axis, the mires
are farther apart and thicker, and the central mire is longer.
The handheld Placido disk is a keratoscope with a flat target.
Collimating keratoscopes use rings inside a column or a curve to
maximize the area of the ocular surface that can reflect the target
mires. Photokeratoscopy preserves the virtual image of concentric
circles on film, and videokeratoscopy stores the images on video.
We aimed in this study to evaluate the use of manual
keratoscope intraoperative to improve the outcome of intracorneal ring
segment implantation in patients with keratoconus.
This was a prospective, consecutive, interventional comparative
case study which included 40 patients with keratoconus. The
participants were randomly divided into two subgroups according to
Summary
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the use of manual keraoscope intraoperative. group A: 20 patients
were operated by non-aided implantation of ICRS without keratoscope
while group B: 20 patients were operated with keratoscope assisted
ICRS implantation.
Results of the current study can be summarized in the following
points:
Regarding refraction sphere (pre-operative and post-operative),
refraction cylinder sphere (pre-operative and post-operative), and
BSCVA (pre-operative), there was a statistically non-significant
difference between groups. While regarding BSCVA (Postoperative),
there was a statistically a significant difference
between groups (p=0.049). group B showed a higher BSCVA
than group A (3.611 vs. 3.601).
Twenty patients ranged in age between 17.0 – 35.0 years with a
mean age of 26.75 ± 4.97 years for group A and 20 patients
ranged in age between 16.0 – 40.0 years with a mean age 28.25 ±
7.08 years for group B.
Regarding refraction SE (Pre-operative and Post-operative), there
was a statistically non-significant difference between groups.
While regarding SE (Pre-operative and Post-operative) within
each group, there was a statistically significant difference
(p<0.001, p= 0.012 in groups A and B respectively). Both Groups
showed a decrease in SE.
Regarding K1 (Post-operative) (p=0.004), K2 (Post-operative)
(p=0.006), K max (Post-operative) (p=0.005), Max elevation
(Front) (Post-operative) (p=0.001), there was a statistically
significant difference between groups.
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Regarding K1 (Post-operative), K2 (Post-operative), K max (Postoperative),
group B showed a lower K1 (42.40 vs 44.70), K2 (45
vs 48.50), and K max than group A (50.2 vs 55.10). While
regarding Max elevation (Front) (Post-operative), group B
showed a higher Max elevation (Front) than group A (28.10 ±
9.88 vs 18.53 ± 6.17).While Within each group, there was a
statistically significant difference Post-operative (p<0.05).
Regarding ACD (Pre-operative and Post-operative), there was a
statistically non-significant difference between groups. While
Within each group, there was a statistically a significant difference
Post-operative (p=0.010 and p<0.001 in group A and B
respectively).
Regarding corneal volume (Pre-operative and Post-operative), that
there was a statistically non-significant difference between groups.
As well as within each group, there was a statistically nonsignificant
difference.