Clinical Trial Details
— Status: Not yet recruiting
Administrative data
| NCT number |
NCT05593263 |
| Other study ID # |
Soh-Med-22-10-17 |
| Secondary ID |
|
| Status |
Not yet recruiting |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
November 15, 2022 |
| Est. completion date |
February 15, 2024 |
Study information
| Verified date |
October 2022 |
| Source |
Sohag University |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
The goal of this is prospective, computer based randomized clinical trial is to compare the
efficacy of reduction of the pre-existing corneal astigmatism at the time of cataract surgery
in patients admitted in sohag university hospital.
the main questions it aims to answer are :
- Is limbal relaxing incisions as effective as the paired opposite 4mm clear corneal
incisions technique in reduction of corneal astigmatism at the time of cataract surgery
?
- Are both techniques effective in treating mild degrees of corneal Astigmatism ?
All participants will have full ophthalmological examination necessary for routine cataract
surgery, then randomly divided into 2 groups, clear corneal incision group & limbal relaxing
incision group.
Researcher will compare difference between both groups regarding the following :
- Uncorrected distance visual acuity (UCVA)
- Best Corrected visual acuity (BCVA)
- keratometry readings
Description:
This is prospective clinical trial will be established in Sohag university hospital. All
cataract patients who will be admitted and meet the study inclusion criteria will be enrolled
in this study. Candidates will be computer based randomly divided into two groups, opposite
clear corneal incisions group & limbal relaxing incision group.
Inclusion criteria:
- Cataract patients aged 21- 80 years.
- keratometric astigmatism 1Diopter - 4 Diopters.
- Healthy clear cornea.
Exclusion criteria:
- History of previous keratorefractive or anterior segment surgery.
- Previous ocular trauma .
- Corneal scar or opacities.
- Irregular corneal astigmatism.
- Cataract unsuitable for phacoemulsification.
- Ongoing chronic ocular pathology
Withdrawal criteria:
- Suturing the wounds.
- Placement of more than 2 side ports.
- Any complication necessitating enlargement of the main incision.
- Wound infections.
- Second procedures within the follow-up period.
- intraocular lens tilt or in sulcus implantation.
Number of patients with adverse events, missed follow ups or changing plans will be
registered and mentioned separately .
Preoperative evaluation:
Full ophthalmological examination will be done for all patients and include:
1. Uncorrected distance visual acuity (UCVA)
2. Best Corrected visual acuity (BCVA)
3. Slit lamp biomicroscopy
4. Refraction
5. Intraocular pressure measurement by (Goldman Applanation Tonometry)
6. Fundus examination.
7. keratometry (autokeratometry, Topcon KR-8900, Tokyo, Japan )
8. Pentacam (Sirius Scheimpflug Placido topography .CSO, Florence, Italy).
9. Evaluation of corneal aberrations( by IOLMaster 700 and the KR-1W Aberrometer (Topcon)
Data will be classified and saved in both hard and soft copies for secure validation and
registry procedures. Two researchers will be responsible for revision of data verification to
assess the accuracy of the registered data and completing it with the postoperative data.
Operative procedures:
All procedures will be performed by the same surgeon using standard phacoemulsification. All
patients will have immediate pre-operative limbal-corneal marking while sitting upright and
looking straight ahead using the slit lamp to avoid any cyclotorsion of the eyeball which
could be induced by lying supine.
Clear corneal incisions group:
During surgery, the Steep meridian will be identified and marked using mendez ring and
marker. Additional marks will be added 20 degree away from both sides of the paired incisions
for further enlargement of the wound to be 4mm. One clear corneal incision will be made on
one side of the steep axis using 2.4mm keratome knife (Alcon Laboratories, Inc., Fort Worth,
TX ) which is kept parallel to the iris plane to maintain an incision width of approximately
1.5 mm for secure wound sealing. Routine phacoemulsification will be performed, then
intraocular lens (IOL) in the bag will be inserted. Just before irrigation/aspiration (I/A)
of the ophthalmic viscoelastic, a second clear corneal incision (CCI) will be made 180
degrees from the first incision. Both incisions will be extended from both sides till
reaching the marking points to be exactly 4 mm by using a keratotomy knife and checked by
surgical caliper.
In cases of against-the-rule (ATR) astigmatism, the opposite clear corneal incisions (OCCIs)
will be made at the 3 o'clock and 9 o'clock positions. The temporal clear corneal incision
will be used for phacoemulsification; the nasal CCI will not be used. In cases of with the
rule astigmatism, the OCCIs will be made at the 12 o'clock and 6 o'clock positions. The
superior CCI will be used for phacoemulsification; the inferior CCI will not be used. In
cases of oblique astigmatism, the OCCIs will be made on the steepest meridian. The surgeon
will choose the most comfortable CCI placement for phacoemulsification; the opposite
symmetrical CCI will not be used. Bimanual I/A will be used in all cases. At the end of
surgery, both incisions will be hydrated.
Limbal relaxing incision group:
The calculations of the length and position of LRI will be done using the Donnenfeld nomogram
with the online calculator; http:// www.lricalculator.com. With the aid of pre-placed corneal
reference marks (as done in the CCI group ), Single or paired LRI will be performed on the
steep axis prior to phacoemulsification procedure using a 600 μm diamond guarded blade
(Geuder LRI diamond knife, blade G-31468, Heidelberg, Germany ) and placed at least 0.5 mm
anterior to the limbus. Using fixation ring, the eye will be fixated and the guarded knife is
inserted at one end of the incision mark, as perpendicular to the corneal surface as
possible, then advanced along the preset incision mark to complete the LRI trying at all
times to maintain its perpendicular orientation. All patients had 2.4 mm clear corneal
incision as the main phacoemulsification incision with no wound enlargement. Surgical induced
astigmatism for the surgeon was previously calculated to be 0.5D which was used for the
online LRI calculator.
All patients will be prescribed antibiotic and corticosteroids eye drops.
Postoperative Evaluation:
Postoperative visits will be scheduled for the first postoperative day for checking of any
possible complications, then at 1 week and 1, 3, 6, months after surgery.
The data will be analysed using SPSS for Windows version 18.0 software (SPSS Inc., Chicago,
IL, USA).The data will be shown as the mean and standard deviation.
Statistical analysis will be performed using the paired-samples t test to evaluate
pre-operative and post-operative data within each group such as VA, keratometry reading,
astigmatism and refraction. Independent-sample t test will be used to evaluate differences in
astigmatism correction between OCCI and LRI groups. Vector analysis of astigmatism correction
was calculated as previously described by Alpins.
