الفهرس 
Aim of the WorkOnly 14 pages are availabe for public view
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Abstract
Conventional approaches to treating mild to moderate keratoconus
involve eyeglasses and rigid gas permeable contact lenses. Nonetheless,
some patients are unable to tolerate contact lens and spectacle correction
is insufficient in some cases.
A combination of corneal collagen cross-linking with
photorefractive keratectomy, a standard laser-assisted refractive surgery
is expected to have greater efficacy in the management of keratoconus.
The main purpose of the combined treatment of keratoconus with
photorefractive keratectomy / corneal collagen cross-linking involves
strengthening the cornea and halting the disease progression by corneal
collagen cross-linking and to improve the quality of
vision via photorefractive keratectomy.
The main objective of this study was to evaluate the effectiveness
of combined corneal collagen cross-linking and topography-guided
photorefractive keratectomy in cases of mild and moderate keratoconus.
This was a clinical trial study was conducted, including20 patients
with grade 1 or 2 stable keratoconus. The duration of the study ranges
from 6 to 12 months. The study included 20 eyes of 10 patients with
grade 1 or 2 stable keratoconus 12 eyes belonged to males (60%) and 8
eyes belonged to females (40%). The age of patients ranged from 20 to 38
years with a mean of 29.7 ± 6.25.A written informed consent was
obtained from all patients. Patients` eyes were examined preoperatively
and post operatively twice (after one month and six months).
The main results of the study revealed that:
There was a statistically significant difference between the mean
preoperative log MAR UDVA (0.87 ± 0.19) and 1-month
postoperative log MAR UDVA (0.49±0.17) (𝑃 < 0.001). UDVA
continued to improve progressively until the end of the 6-month
follow-up period (0.30 ± 0.15) that was statistically significant (𝑃 <
0.001).
There was not statistically significant difference between the mean
preoperative log MAR CDVA (0.31 ± 0.13) and 1-month
postoperative log MAR CDVA (0.30 ±0.15) (𝑃 > 0.05). UDVA
continued to improve progressively until the end of the 6-month
follow-up period (0.30 ± 0.15).
The means of maximum and minimum keratometry preoperatively
were (49.6±4.79) and (45.7±3.2) respectively and one month postoperatively
they improved to (46.5±3.6) and (44.05±3.7)
respectively with statistically significant difference (p<0.001) and
continued significant improvement till 6-month follow-up period to
(46.4±3.8) and (43.5±3.6) respectively (p<0.001)
The median of cylindrical error was 2.25 diopter preoperatively
and 1- and 6- month postoperatively was 1.25 and 1.125 diopter
respectively with statistically significant improvement (p<0.05)
In summary, combining corneal collagen cross-linking to refractive
surgeries such as topography-guided photorefractive keratectomy is
found to be a safe and effective method in providing corneal stability as
well as significantly improving functional visual acuity with few minor
complications. This combined technique also prevents regression of
keratoconus and reduce the risk of keratectasia. Corneal collagen crosslinking
combined with photorefractive keratectomy is a promising
therapeutic approach in ophthalmology that can be successfully used to
treat progressive keratoconus and other corneal ectatic disorders and to
enhance visual acuity.