Astigmatism, Phacoemulsification
Conditions
Brief summary
To compare the effect of Limbal relaxing incisions (LRIs) plus spectacle correction versus spectacle correction alone on subjective and objective improvement in visual function for correcting post phacoemulsification high astigmatism .
Detailed description
Astigmatism is one of the commonest refractive errors encountered during our clinical practice. Surgically induced astigmatism is the main obstacle to achieve good uncorrected visual acuity following cataract surgery. It is estimated that corneal astigmatism of more than 1.0 diopter (D) is found in up to 40% of patients presenting for cataract surgery, 1.5D or more is present in over 20% and above 2.0D in 10%. Astigmatism induces distortion of the image leading to compromise quality of vision. In order to achieve better visual results, the effect of postoperative astigmatism should be minimized, management options for corneal astigmatism include glasses, contact lenses, and surgery such as Limbal relaxing incisions (LRIs), refractive laser surgery, toric lenses or rarely corneal grafting. The LRIs technique involves the placement of incisions corresponding to the steep meridian, resulting in corneal flattening and the reduction of astigmatic power. LRI is a safe and an inexpensive procedure, which is simple for experts to perform. Although most of the nomograms recommended that LRIs technique can correct up to 3 D of astigmatism ,it has been found that it is possible to correct even more than 4 D if the incisions were performed on high degrees of astigmatism.
Interventions
PROCEDURELimbal relaxing incisions
A fixed depth diamond-guarded knife (Gemcision LRI 600 Microns Blade, Katalyst Surgical, chesterfield, MO, USA) will be used to create a paired circumferential corneal incision, following the limbal curvature, 1-1.5mm anterior to the limbus centered on the steep corneal meridian. The incision arc length will be ninety degree according to the Nichamin Age and Pachymetry Adjusted (NAPA) nomogram.
Sponsors
Assiut University
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Conventional phacoemulsification was done at least one month earlier. * Clear cornea with corneal astigmatism more than 3.0 D.
Exclusion criteria
* History of corneal surgeries (e.g., keratoplasty, refractive surgery, and corneal wound repair). * Ocular trauma. * Other intraocular surgery. * Patient with corneal opacities. * Thin cornea . * Any significant ocular disease causing diminution of vision (e.g., optic atrophy, diabetic retinopathy, and age-related macular degeneration), autoimmune disease, and peripheral corneal disease.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| visual acuity improvement | 3 months | assessment the improvement in visual acuity ,which will be measured by Landolt Cs chart with decimal notation. |
| contrast sensitivity improvement | 3 months | Assessment the improvement in contrast sensitivity using Pelli-Robson contrast sensitivity test . |
Contacts
Primary Contactyoustina shaheir gad, resident doctor
Outcome results
None listed