Children have a softer lens than adults, so cataract surgery in children may give the impression that it is easy for the ophthalmology clinician to perform, but this may not be the case. While pediatric cataract surgery may appear to be easy, it requires a delicate surgical design and approach based on the extensive clinical experience of the ophthalmology clinician.
According to ASCRS, the number of pediatric cataract surgeries performed by ophthalmologists per capita is only 7 per year. Moreover, children are not miniature adults and have unique anatomical, physiological, psychological and social conditions: children’s eyes are smaller and have softer tissues than adults; adult cataracts only affect vision, while children can also affect visual (brain) development, and the cloudy lens of infants and children prevents clear imaging of the retina and interferes with the development of the visual pathways of the central nervous system. Therefore, preoperative, intraoperative and postoperative cataract surgery in children is far more complex than in adults, and the timing of surgery, surgical technique, selection of IOL degree and amblyopia treatment are important factors in obtaining effective results in children with cataract.
Cataract surgery in children differs from adult surgery in the following ways: cataracts in children are difficult to diagnose, often diagnosed late, and often combined with other ocular abnormalities and systemic diseases; timing of surgery is more important than surgical technique in children than in adults; and there are concerns about general anesthesia and the accuracy of examination under general anesthesia. There are also concerns about general anesthesia and the accuracy of the examination under general anesthesia. In addition, it is difficult to calculate the IOL for cataract surgery in children.
The main intraoperative differences are: the physiological anatomy of children’s eyes is smaller, the pupil diameter is smaller, the sclera is less rigid, and the ciliary flat is relatively small in children, and the ciliary flat is not fully developed; the incision and suture for cataract surgery in children is better for the upper corneal tunnel incision, and the surgical incision should be sutured; the vitreous body is thick in children, and the scleral wall is thin, which leads to higher vitreous pressure and intracrystalline pressure, and the surgery It is difficult to tear the capsule of the anterior/posterior capsule membrane during surgery; the mechanized membrane of the posterior capsule is more common in children with cataract, which requires the use of a botanical head or even intraocular scissors to remove, and the posterior capsule needs to be treated intraoperatively in children with posterior YAG cataract who cannot cooperate with the surgery, so children also need botanical equipment and techniques for cataract surgery.
Postoperative differences are mainly divided into the following aspects: posterior cataracts occur in all children after cataract surgery; postoperative inflammatory reactions are heavy, but children have poor compliance with postoperative local medication; postoperative children need frequent correction of refractive error as the eye grows, and poor patient cooperation leads to difficulty in intraocular, visual acuity and refractive status examinations, and young children do not recognize words and need to use other examinations, so when outpatient examinations are not cooperative Short-acting anesthesia is needed; postoperative amblyopic tendency requires masking treatment; long-term follow-up is important but difficult.
And there is no definite conclusion on whether pediatric cataracts can be treated conservatively. Some of the experts who advocate conservative treatment at this stage are as follows: Faye proposes the use of weak dilators for nuclear cataracts, qd or bid, with increasing doses as needed; Chandler proposes that many failures have led us to realize that surgery is not the first choice unless the vision is very low; DeVoe proposes that 20/50 vision with accommodation is better than 50/50 vision without accommodation. We now recommend that monocular incomplete cataracts are usually treated conservatively, and conservative practitioners also suggest that bilateral cataracts should not be removed at visual acuities above 20/70 to 20/50. In the early years, the general opinion was that surgery was not considered as long as the fundus could be seen, so cataracts with a cloudy central lens and a relatively clear periphery were often treated conservatively.
Cataract surgery for children The principle of cataract surgery for children is to remove cataract early during the critical period of visual development, to correct refractive error in aphakic eyes, and to avoid irreversible visual deprivation amblyopia. Specifically for pediatric cataract patients with monocular onset or binocular onset: monocular total mixed cataract needs to be operated within 4 months after birth; binocular nuclear cataract can be delayed; monocular onset and total cataract especially should be operated as early as possible, and the second eye of both eyes should not be operated too long apart.
As for the age selection of IOL implantation for pediatric cataract surgery: IOL implantation is mostly not recommended for pediatric patients <1 year old because their postoperative inflammatory reaction is strong and difficult to control, and it is difficult to determine the appropriate degree and size; patients aged 1-2 years are more controversial and inconclusive; patients aged >2 years are not controversial for IOL implantation. This is because patients <2 years old have a capsular bag diameter of 7mm, 10mm after expansion of the elastic capsule, and patients ≥2 years old have the same capsular bag diameter as adults 12mm, while the IOL diameter is about 10.5~11mm, so IOLs should not be implanted in patients <2 years old. The principle of IOL determination is to provide good refractive correction to obtain satisfactory visual acuity after treatment and not to form high myopia after the development of the affected eye. In children, the eye axis length at birth is 16mm, refractive state +30-+35D, and the eye axis increases by 4mm at the age of 1 year, 1mm is about 3D, and myopic drift occurs as the eye axis increases: about -3D (within 2 years) at the age of 0~2 years, about -1.5D (within 3 years) at the age of 3~5 years, about -1.0D (within 3 years) at the age of 6~8 years, and about -0.38D (within 2 years) at >8 years. Therefore, the choice of IOL degree after 8 years of age for pediatric cataract surgery is based on the measured degrees, while a certain number of degrees of hyperopia needs to be set aside before 8 years of age.
Summary and outlook Cataract surgery in children may seem easy, but it requires ophthalmology clinicians to adopt delicate surgical design and operation based on rich clinical experience. Finally, a summary and outlook are presented: biosurgery plus posterior capsulotomy has become the standard procedure for cataract surgery in infants and children. Posterior capsulotomy without combined biosection is only suitable for children over 4 years old. Flat section cutting will become more of an option; for infants up to 6 months of age, the least invasive procedure is a two-handed, closed anterior chamber, microincisional approach that includes posterior capsulotomy, anterior segment biosection, and no IOL implantation. small eye surgery is performed within 6 months of age; epithelial hyperplasia and pupillary area membranes are common; no IOL implantation should be performed up to 6 months of age. IOL implantation is recognized after at least 1 to 2 weeks of age. IOL implantation within 6 months of age is significantly traumatic, requires secondary surgery and makes it difficult to select an appropriate IOL; for second-stage IOL implantation older than 2 years of age, the goal is to select an appropriate IOL that does not leave a very high degree of hyperopia so that it does not exceed moderate myopia at age 20. It is ideal to control the residual refractive error between +3 and -3D; for surgery before 6 months of age, do not implant the IOL in the Phase I capsule. If necessary, ciliary sulcus implantation should be chosen to facilitate IOL replacement; multifocal IOLs are still mainly suitable for adults and some adolescents, and multifocal cannot synchronize visual changes due to myopic drift is not recommended for children’s eyes; predicting the growth rate of the eye axis and refractive changes are issues and adjustments that need long-term attention after cataract surgery in children, and more in-depth understanding of the growth state of the eye after cataract surgery is needed in the future and The IOL calculation formula applicable to children’s eyes needs to be summarized; amblyopia treatment in aphakic or IOL eyes needs to be further investigated, and in addition to in-depth research on the quantitative protocol and frequency of postoperative masking treatment, methods to extend the plasticity of the visual system also need to be further explored, such as the feasibility of drug treatment.