INTRODUCTION Cataract surgery since its inception up to now has gone through many leaps and bounds. Along with advances in phaco surgery, intraocular lenses (IOLs) have also been constantly improved. Many new types of IOLs have contributed to significantly improving patients'' vision and improving the quality of surgery. The goal of modern cataract surgery is to not only restore visual acuity to emmetropia, but also provide clear images at all distances, both far vision, near vision and intermediate vision. That can only be achieved with multifocal intraocular lenses. However, for patients with a degree of astigmatism from onediopter (D)or above, the indication for multifocal intraocular lenses is limited because this type of IOLs can only adjust spherical refraction but not cylindrical refraction. In clinical practice, about 30% of eyes undergoing cataract surgery have corneal astigmatism of one or more diopters. When these patients really want to have multifocal IOLs, the surgeon will have to perform additional astigmatism correction surgery such as edge corneal incision or symmetrical corneal incision during phaco surgery. After cataract surgery, laser refractive surgery can be used to correct the remaining refractive errors including astigmatism. However, in addition to the disadvantages of an additional surgery such as funding and time, it is also related to limited predictive results, dry eyes and wound recovery problems. Acrysof ReSTOR Toric (ART) multifocal toricintraocular lens has provided phaco surgeons the best method to treat cataract patients with corneal astigmatism who need multifocal IOLs. This type of IOL both provides distance visual acuity, intermediate visual acuity, near visual acuity, and corrects existing astigmatism that patients undergo a single phaco surgery. In Vietnam, ART has been put into use, but there is no systematic, large-scale study of the surgical outcome of this IOL. Therefore, we conduct research on this topic with the following objectives: 1. Evaluate the effectiveness of phacoemulsification surgery with Acrysof ReSTOR Toric intraocular lens implantation. 2. Analysis of several factors related to surgical results The urgency of the subject Cataracts are the leading cause of blindness in Vietnam. Phaco surgery with intraocular lens has brought light to the patients, improving the quality of life. Today, cataract surgery is considered as refractive surgery, requiring accurate visual acuity results as well as precise and delicate postoperative refraction to improve the quality of treatment. Along with advances in surgical techniques, types of intraocular lenses are constantly being improved both in terms of biological material and optical properties to improve visual acuity at all distances. According to research by some authors, about 30% of cataract surgery patients have corneal disorders of one or more diopters. If these patients have a conventional multifocal IOL, even though their visual acuity improves, they may still see blurred visual acuity. Phaco ART IOLs surgery both brings distance visual acuity, intermediate visual acuity, near visual acuity, and corrects corneal astigmatism that patients only need one surgery. Therefore, the study of using Acrysof ReSTOR Toric IOL in phaco surgery to treat patients with cataract with corneal astigmatism is a necessary research topic. The thesis has scientific significance and practical value, consistent with the development trend of cataract surgery, thoroughly solving refractive abnormalities for cataract patients. New contributions of the thesis This is the first project in Vietnam that has studied quite comprehensively the results of phaco surgerywith multifocal toric intraocular lens implantation. The thesis has assessed the effectiveness of visual acuity, corrected available corneal astigmatism before surgery, reduced dependence on glasses, and increased visual quality for patients. At the same time, the thesis also assesses the safety of surgery with low rate of complications during and after surgery, without serious complications. The thesis also gives some experience on calculation method, IOL capacity selection to achieve the best results. Layout of the thesis The thesis consists of 131 pages, including: Introduction 2 pages; Chapter 1 - Overview 33 pages; Chapter 2 - Subjects and research methods 19 pages; Chapter 3 - Research results 31 pages; Chapter 4 - Discussion 41 pages; Conclusion 2 pages; Request 1 pagesThe thesis consists of 42 tables, 14 charts, 8 pictures, 108 references.
1 INTRODUCTION Cataract surgery since its inception up to now has gone through many leaps and bounds Along with advances in phaco surgery, intraocular lenses (IOLs) have also been constantly improved Many new types of IOLs have contributed to significantly improving patients' vision and improving the quality of surgery The goal of modern cataract surgery is to not only restore visual acuity to emmetropia, but also provide clear images at all distances, both far vision, near vision and intermediate vision That can only be achieved with multifocal intraocular lenses However, for patients with a degree of astigmatism from onediopter (D)or above, the indication for multifocal intraocular lenses is limited because this type of IOLs can only adjust spherical refraction but not cylindrical refraction In clinical practice, about 30% of eyes undergoing cataract surgery have corneal astigmatism of one or more diopters When these patients really want to have multifocal IOLs, the surgeon will have to perform additional astigmatism correction surgery such as edge corneal incision or symmetrical corneal incision during phaco surgery After cataract surgery, laser refractive surgery can be used to correct the remaining refractive errors including astigmatism However, in addition to the disadvantages of an additional surgery such as funding and time, it is also related to limited predictive results, dry eyes and wound recovery problems Acrysof ReSTOR Toric (ART) multifocal toricintraocular lens has provided phaco surgeons the best method to treat cataract patients with corneal astigmatism who need multifocal IOLs This type of IOL both provides distance visual acuity, intermediate visual acuity, near visual acuity, and corrects existing astigmatism that patients undergo a single phaco surgery In Vietnam, ART has been put into use, but there is no systematic, large-scale study of the surgical outcome of this IOL Therefore, we conduct research on this topic with the following objectives: Evaluate the effectiveness of phacoemulsification surgery with Acrysof ReSTOR Toric intraocular lens implantation Analysis of several factors related to surgical results The urgency of the subject Cataracts are the leading cause of blindness in Vietnam Phaco surgery with intraocular lens has brought light to the patients, improving the quality of life Today, cataract surgery is considered as refractive surgery, requiring accurate visual acuity results as well as precise and delicate postoperative refraction to improve the quality of treatment Along with advances in surgical techniques, types of intraocular lenses are constantly being improved both in terms of biological material and optical properties to improve visual acuity at all distances According to research by some authors, about 30% of cataract surgery patients have corneal disorders of one or more diopters If these patients have a conventional multifocal IOL, even though their visual acuity improves, they may still see blurred visual acuity Phaco ART IOLs surgery both brings distance visual acuity, intermediate visual acuity, near visual acuity, and corrects corneal astigmatism that patients only need one surgery Therefore, the study of using Acrysof ReSTOR Toric IOL in phaco surgery to treat patients with cataract with corneal astigmatism is a necessary research topic The thesis has scientific significance and practical value, consistent with the development trend of cataract surgery, thoroughly solving refractive abnormalities for cataract patients New contributions of the thesis This is the first project in Vietnam that has studied quite comprehensively the results of phaco surgerywith multifocal toric intraocular lens implantation The thesis has assessed the effectiveness of visual acuity, corrected available corneal astigmatism before surgery, reduced dependence on glasses, and increased visual quality for patients At the same time, the thesis also assesses the safety of surgery with low rate of complications during and after surgery, without serious complications The thesis also gives some experience on calculation method, IOL capacity selection to achieve the best results Layout of the thesis The thesis consists of 131 pages, including: Introduction pages; Chapter - Overview 33 pages; Chapter - Subjects and research methods 19 pages; Chapter - Research results 31 pages; Chapter - Discussion 41 pages; Conclusion pages; Request pagesThe thesis consists of 42 tables, 14 charts, pictures, 108 references Chapter 1: OVERVIEW 1.1 Corneal astigmatism and methods to correct corneal astigmatism in cataract patients 1.1.1 Corneal astigmatism * The definition of corneal astigmatism * Methods to identify corneal astigmatism in cataract patients:manual corneal refractometry, corneal refractive map, and IOL master measurement * Astigmatism after cataract surgeryis the combination of pre-operative astigmatism and surgery induced astigmatism Methods of analyzing astigmatism: The vector analysis method is preferred because it is quite simple and produces relatively accurate results 1.1.2 Methods to correct corneal astigmatism in cataract patients 1.1.2.1 Wear glasses * Eyeglass frames: Simple, safe but inconvenient in daily life, the visual acuity scope is narrowed and not aesthetic * Contact lens: aesthetics and does not cause a narrowing of the visual acuity scope but the downside is the problem of preserving contact lenses, epithelial damage, corneal shape changes, corneal infections 1.1.2.2 Additional laser surgery Conducted about months after cataract surgery, the results were relatively accurate However, the patient underwent another operation, which was expensive and aggravated the condition of dry eyes 1.1.2.3 Phaco surgery combined with corneal incision * Surgical corneal incision surgery: create a pair of arcs in the symmetrical fringe region through the cornea meridians with the highest refractive power with depth of incision more than 90% of the cornea thickness This technique is easy to implement, low cost but the disadvantage is to use a complex algorithm to determine the length and depth of the incision, difficult to predict the results Contraindicated in eyes with too high or low K values or thin border corneal thickness * Phaco surgery with symmetrical corneal incision through phaco incision: The surgeon opens the cornea through a corneal incision at the cornea edge on the corneal meridian with the highest refractive power After performing the phaco surgery, putting the IOL into the capsular bag, the surgeon performs the second corneal incision symmetrical with the first incision at the vascular edge of the meridian at the highest meridian of refraction This method is simple, easy to implement, does not cause much damage to the structure of the cornea, but only applies to cases of mild and moderate corneal astigmatism The results are unpredictable and unstable due to regression of effects over time 1.1.2.4 The method of using toric intraocular lenses * Principles: Types of toric intraocular lenses are composed of two parts integrated together: the aspherical and the cylindrical sections The cylinder power portion of the intraocular lens will add the power to the flat K of the cornea, which equals the power of the steep K and is marked with an axisso that when it is placed in lens bags will coincide with the marker axis on the cornea, thus, will eliminate astigmatism caused by the cornea * Advantages: safe, easy to perform, effective and accurate, correcting astigmatism right at the time of cataract surgery, predicting residual astigmatism after surgery This technique does not depend on the scar healing or regressive reactions of the cornea, so the results are highly stable Applicable to patients with cataracts with corneal astigmatism ≥ 1.0D * Disadvantages: IOL axis rotation problem 1.2 The effect of phaco surgery with Acrysof ReSTOR Toric intraocular lens implantation 1.2.1 Acrysof ReSTOR Toric (ART)intraocular lens * Structure: ART was first introduced in the United States in 2010 ART is built on the basis of ReSTOR Multifocal and Acrysof Toricintraocular lenses Currently, ART has samples SND1T2, SND1T3, SND1T4, SND1T5, SND1T6 with cylindrical glass power range at 0.68D, 1.03D, 1.55D, 2.06D and 2.57D, respectively The capacity ofcylinders at IOL plane accordingly is 1D, 1,5D, 2,25D, 3,0D and 3,75D, respectively * Design: Toric aspherical double-sided convex diffraction lens, 6mmin diameter, 13mm in length, L-shaped with flexible folding angle helps stabilize rotation, accurate correction astigmatism, long-term stability * Biological properties: ART is made of hydrophobic acrylic material with a refractive index of 1.55 to reduce posterior capsule opacification 1.2.2 The effect of phaco surgery with ART intraocular lens implantation 1.2.2.1 Visual acuity results Research by Hayashi K et al (2015) on groups: group uses ART, group uses monofocal toric, which showed that near visual acuity and intermediate visual acuity in the ART group was significantly better than the group who placed the monofocal toric while distance visual acuity was similar About 95% of ART patients not have to wear glasses, while 88% of patients who use monofocal toric lenses must wear glasses to look close The satisfaction of patients with near visual acuity in group was higher than in group 2, while distance visual acuity was similar Research by Michael C et al At months after surgery, 95% of patients not need glasses for near and distance visual acuity activities This proves that ART gives patients good visual acuity at all distances including distance, near and intermediate without glasses 1.2.2.2 Refractive results A study by Alfonso JF (2014) on 88 eyes operated with ART phaco surgery showed that six months after surgery, cylinder refraction decreased significantly compared to before surgery showing a statistical significance with p 3mm The average pupil size is 2.83 ± 0.51 mm 3.1.6.ART samples used in surgery SND1T4 and SND1T5 are the two most used ART samples, accounting for 82.7%, SND1T3 accounting for 9.6% and SND1T6 accounting for 7.7% 3.1.7 The location of the incision The location of the incision is mainly located on the curved meridian (67.31%), with 23.08% of the incision located on the flat meridian, the other meridians account for 9.61% 3.2 The effect of phaco surgery with Acrysof ReSTOR Toric intraocular lens implantation 3.2.1 Visual acuity results 11 * Distance visual acuity after surgery: In 52 surgical eyes, uncorrected visual acuity (UDVA) in the average is 0.13 ± 0.08 logMAR at week time with 96.16% of eyes with visual acuity from 20/40 and above At month, the average UDVA was 0.09 ± 0.08 logMAR with 98.07% of the eyes with visual acuity of 20/40 and above, 76.92% of the eyes with visual acuity of 20/25 or more At months and months, the visual acuity does not change compared to the time after month of surgery At 12 months, 75% of eyes have visual acuity of 20/25 or more, there are eyes (5.77%) of visual acuity below 20/40 The average maximum corrected distance visual acuity (CDVA) average is 0.05 ± 0.06 logMAR at week time with 88.46% of eyesight of 20/25 or more At month, the average CDVA is 0.01 ± 0.08 logMAR with 94.23% of eyes with eyesight of 20/25 or more At and months, the visual acuity does not change At 12 months, 92.31% of the eyes have eyesight of 20/25 or more * Near visual acuity after surgery:1 week after surgery, the average uncorrected near visual acuity (UNVA) averages 0.21 ± 0.08 logMAR, of which 80.77% of the eyes have visual acuity of 20/40 or more At month, months and months after surgery, the average UNVA is 0.18 ± 0.07 logMAR with 90.38% of eyes with eyesight of 20/40 or more At 12 months postoperatively, the average UNVA was still 0.18 ± 0.07 logMAR and 86.54% of the eyes had visual acuity of 20/40 or more of which 44.23% of visual acuity was above 20/25 The average maximum corrected near visual acuity (CNVA) is 0.06 ± 0.07 logMAR at week intervals with 76.92% of eyesight of 20/25 or more At month, months, months, 12 months after surgery, the average CDVA is 0.05 ± 0.06 logMAR with 86.54% of the eyes with visual acuity of 20/25 or more At 12 months, 3.85% of eyes have visual acuity below 20/40 * Intermediate visual acuity post-surgery:After week of surgery, the uncorrected intermediate visual acuity (UIVA) averages 0.18 ± 0.08 logMAR, of which 90.38% of eyes have visual acuity of 20/40 or more At month, months and months after surgery, the average UIVA is 0.13 ± 0.07 logMAR with 92.31% of eyes with visual acuity of 20/40 or more At 12 months postoperatively, the average UIVA is still 0.13 ± 0.07 logMAR and 88.46% of eyes have visual acuity of 20/40 or more The average corrected intermediate visual acuity (CIVA) averages 0.03 ± 0.05 logMAR at week interval with 76.92% of eyes with visual acuity of 20/25 or more At the time of month, months, months, 12 months after surgery, the average CIVA is 0.03 ± 0.05 logMAR with 88.46% of eyes with visual 12 acuity from 20/25 or more At 12 months, 3.85% of eyes have visual acuity below 20/40 3.2.2 Refractive results Out of 52 phaco surgical eyes with ART, the number of eyes with residual refractive sphere ≤0.5D accounted for 94.23% at week and 98.02% at the time after surgery month to 12 months Refraction sphericalequivalent after surgery mainly ranges from -0.5D to + 0.5D at the rate of 88.46% at week, 92.31% at month, 94.23% at months to 12 months Cylinder refraction after week surgery had 76.92% of eyes below 0.5D of which 32.69% of astigmatism was within 0.25D Cylindrical refraction does not change from the 3rd month onwards, 100% of eyes have cylindrical refraction below 1.0D At the time of week postoperative, the average residual astigmatism reached -0.45 ± 0.59D, then gradually decreased to -0.37 ± 0.54D month after surgery and stabilized at -0, 32 ± 0.47 D from months onwards to 12 months although the average corneal astigmatism is almost unchanged at the time after surgery compared to before surgery The residual astigmatism in SND1T3 group was the lowest at -0,13 ± 0,58D and the SND1T6 group with the highest residue was about -0,39 ± 0,19D * Analysis of treatment results for astigmatism by Alpin method Expected level of Target-induced astigmatism (TIA) 1,76 ± 0,81D The level of surgically-induced astigmatism achieved (SIA): at all times achieve a level that approximates TIA At the time of year is 1.65 ± 0.77D The level of astigmatism required to achieve the desired result (DV - difference vector):at later times, the index varies from 0.34 to 0.36 D Correction index (CI): 1,03 ± 0,12 Index of success (IS) above 86% from week after surgery 3.2.3 Frequency of wearing glasses: In 52 surgical eyes, 96.15% not need to wear distance glasses, 90.38% not wear glasses for intermediate visual acuity and 86.53% not wear glasses when they look closely Only 3.85% of eyes have to wear glasses often when looking closely and intermediately The difference was statistically significant p< 0.001 3.2.4 Contrast sensitivity In our study, 90.38% of eyes had normal contrast sensitivity, only 9.61% of eyes had decreased contrast sensitivity 3.2.5 Complications during and after surgery * Complications during surgery Of the 52 surgical eyes, none of the eyes experienced ruptured anterior capsular bag, hemorrhagic anterior chamber or burn wound Only eye (1.92%) had a Descemet membrane tearing around the incision 13 * Complications after surgery In our study, there were eyes (5.77%) of cornea edema week after surgery, mostly near the surgical edge and the cornea returned back to normal after weeks One eye (1.92%) had anterior uveitis with mild severity and responded to anti-inflammatory medication within month of treatment.There are eyes (3.85%) with posterior capsule opacification We have not experienced any severe cases that seriously affect postoperative visual acuity such as anterior chamber defect, glaucoma, retinal detachment, or cystic macular edema * IOL axis deflection day after surgery, eyes (9.62%) had an IOL deflection but 100% were under degrees with an average deviation of 2.06 ± 0.08˚ After week of surgery, 15.38% of eyes had an IOL deviation of which 75% were under degrees, 25% were from degrees to degrees, the average axis deviation was 2.42 ± 1.12˚ month to 12 months after surgery, there were 17.31% of IOL axis deviation of eyes, 100% were below degrees, the average axis deviation was 2.28 ± 1.34˚ * Visual disorders In 52 surgical eyes, there were 26.92% of eyes had glare phenomenon, 17.31% of eyes had halo phenomenon 3.2.6 Patient satisfaction level 100% of patients were satisfied with the surgery results, of which 88.46% of patients were very satisfied with the surgery results The average VF-14 points for 52 surgical eyes is 96.76 ± 3.88 of which 86.54% of eyes are able to perform all operations 3.3 Several factors related to surgical results 3.3.1 Pupil size * Relationship between pupil size and visual acuity: The pupil size is not related to distance visual acuity but is related to near and intermediate ones The distance visual acuity acuity of groups with pupil sizes from less than 3mm and the groups above 3mm is similar However, near and intermediate visual acuity in the group of pupil sizes below 3mm is better than that in the group of pupil sizes above 3mm The difference was statistically significant p< 0.05 * Relationship between pupil size and visual function: Out of eyes with reduced contrast sensitivity, eyes have a pupil size of 3mm or more The pupil size affects the contrast sensitivity with statistical significance with p 0.05 * Relationship between incision location and visual function: There is no relationship between the incision position and contrast sensitivity, glare or halos with p> 0.05 * Relationship between incision site and residual astigmatism: Among 35 eyes that the incision is placed on curved meridian, 32/35 (91.43%) eyes have residual astigmatism less than 0.5D When the incision is placed on a flat meridian, there are 4/12 (33%) eyes with residual astigmatism of 0.5D or more This difference is statistically significant with p