study of presbyopia-correcting intraocular lenses in eyes with previous corneal refractive surgery

Conditions: Cataract; Presbyopia

Summary: this is a single-center, randomized, open, positive product, parallel controlled trial to evaluate the clinical outcomes of presbyopia-correcting intraocular lenses(iols) in eyes with previous corneal refractive surgery. specific aim 1 (primary): to compare the surgical successful rate of multifocal and extended depth-of-focus iols with monofocal iols for the treatment in eyes with previous corneal refractive surgery. specific aim 2 (secondary): to study the suboptimal surgical outcomes between multifocal and extended depth-of-focus iols with monofocal iols for the treatment in eyes with previous corneal refractive surgery.

recently, the demands for myopia correction and corneal refractive laser surgery are rising with the increased prevalence of myopia. corneal laser refractive surgery includes photorefractive keratectomy (prk), laser-assisted in situ keratomileusis (lasik), laser-assisted subepithelial keratomileusis ( lasek), femtosecond assisted laser in situ keratomileusis (fs-lasik), and small incision lenticule extraction(smile). at present, fs-lasik and smile are the mainstream methods for correcting myopia refractive surgery with advantages of safety, reliability, predictability and stability compared with other types of refractive surgery. cataract is the most important cause of blindness in my country and even in the world. more than 50% of blind people are caused by cataract. many patients who have undergone corneal laser refractive surgery may develop presbyopia or cataracts with age. phacoemulsification and intraocular lens(iols) implantation are the main methods for cataract due to lacking effective pharmaceutical treatments. in addition, the patients who use traditional monofocal iols without the ability of accommodation may fail to get rid of glasses. therefore, a solution that can provide both distance vision and near vision is needed to the presbyopia or cataracts patients with previous corneal refractive surgery and accustomed to taking glasses off.the application of presbyopic iol in cataract after corneal refractive surgery become extensive with the iol technology continuously advancing, including extended depth-of-focus(edof) iol, multifocal iol(especially trifocal iol) and so on, which can improve the distance, middle, and near visual acuity conducing to reduce the rate of wearing glasses after cataract surgery. this project is a single-center, randomized, open, positive product, parallel controlled trial to study the clinical outcomes and applied value of presbyopic iols, including edof and trifocal iols after corneal laser refractive surgery complicated with cataracts, and seek better solutions to enable patients to achieve satisfactory visual quality and refractive results after surgery, culminating in completing patients' demand of taking glasses off.

Eligibility criteria:
inclusion criteria: * the operated eye has ever undergone corneal refractive surgery, including prk, lasik, lasek, fs-lasik, smile and excluding rk * at least one eye suffering from cataract and expected to undergo phacoemulsification and iol implantation and cataract nuclei rigidity in the operated eye from 1 to 3 degree * expected to use intraocular lens power in -10.0d\~+30.0d * willing and able to comply with scheduled visits and other study procedures. * the need to decrease the dependence of glasses * signing an informed consent form exclusion criteria: * any vision-limiting problems (e.g., corneal, retinal, infection) which could potentially limit their post-operative visual potential * any newly acquired ocular condition or pathology (e.g., armd, epiretinal membrane, chronic dry eye, irregular astigmatism, diabetic retinopathy) * the density of corneal endothelial cells is lower than 2000/mm2 * the natural diameter of the pupil under the darkroom is less than 3mm or greater than 5.5mm * the kappa or alpha angle of the operated eye is greater than 0.5mm, or the kappa angle is greater than half of the diameter of the central refractive optical zone in the multifocal intraocular lens * patients with expected best corrected distance visual acuity(bcdva) less than 0.5 (decimal vision) * occurrence of irregular corneal astigmatism that affects postoperative vision * intraocular conventional surgery within the past three months or intraocular laser surgery within one month in the operated eye * pregnant, lactation or planning to become pregnant in the near future * any surgical contraindications * uncontrolled systemic or ocular disease * use of any systemic or topical drug known to interfere with visual performance * other ocular surgery at the time of the cataract extraction * traumatic cataract or congenital bilateral cataract in the operated eye * getting used to reading with glasses * high requirements for visual functions in patients' career or daily life * professional drivers or frequent outdoor workers at night * a medical history of photophobia * amblyopia * excessive vision expectations after surgery or too sensitive, nervous, depressed or picky * unsupervised or unable to comply with scheduled visits * the contralateral eye was judged to lose visual function * other situations where the researcher judges that the patient is not suitable for inclusion

Keywords: post-corneal refractive surgery presbyopia-correcting iol cataract efficiency safety