Surgical challenges of posterior optic capture in pediatric cataract surgery

PURPOSE

The efficacy of posterior optic capture (POC) in reducing posterior capsule opacification (PCO) in pediatric cataract is well recognized. The purpose of this paper was to identify the surgical challenges when attempting this technique and highlight the etiquettes to follow when performing this maneuver.

METHODS

Prospective observational noncomparative case series. Children diagnosed with congenital or developmental cataracts undergoing cataract surgery and primary IOL implantation with posterior optic capture (and no anterior vitrectomy) from June 2017 to April 2022 at a tertiary care referral institute were included. Records of all intraoperative findings and postoperative complications until the last follow-up were noted.

RESULTS

Posterior optic capture was attempted in 53 eyes of 49 children aged 2.4 ± 1.98 years. The mean follow-up of the patients was 16.5 ± 14.2 months (range 6 months-5 years). Successful POC could be performed in 46 eyes (86.8%). Two eyes developed posterior capsular opacification at the last follow-up. In eyes where POC could not be performed, five of these (83%) were children below 12 months of age with half of them having a preexisting posterior capsular defect.

CONCLUSION

Posterior optic capture is technically challenging with a steep learning curve that can be mastered over time. Adequate relative sizing of the anterior and posterior capsulorhexis is important. Caution is advised when using this technique in infants and in cases with posterior capsular defects.

Long-term outcomes of single monocular resection-recession in adult sensory strabismus and factors affecting the postoperative drift

Purpose

The purpose of our study was to analyze the clinical characteristics and outcome of horizontal strabismus surgery in patients having sensory strabismus and to analyze the factors that affect the postoperative drift in these patients over a follow-up of three years.

Methods

This was a retrospective case series. Patients aged ≥18 years, having low vision (visual acuity ≤20/60) in one eye, and undergoing horizontal strabismus surgery (standard recess-resect procedures) in the same eye were recruited. All patients were advised patching of the good eye six weeks prior and continued for six weeks post strabismus surgery. We excluded patients who had paralytic disorders, motility defects, or those with chronic systemic conditions. Patients with a minimum follow-up of three years were recruited.

Results

The study included 56 patients whose mean age was 22.9 ± 4.93 years. Exotropia (n = 38; 67.8%) was more common than esotropia (n = 18; 32.1%). Preoperative visual acuity was 1.1 ± 0.85 (range perception of light to 6/18p). The cause of low vision was amblyopia (n = 30; 53.5%) followed by trauma (n = 22; 39.2%). The mean preoperative distance deviation was 57.7 ± 15.5 PD in the primary position (range: 20-65 PD). The success rate of exotropia (78.9%) was more than esotropia (52.9%) at three years. Two patients with esotropia were overcorrected. All patients with exotropia showed an exotropic drift with time.

Conclusion

The motor alignment after a single recession-resection procedure was satisfactory at the long-term in our cohort of sensory strabismus. The duration or extent of visual impairment had no relation to the postoperative outcome.

Posterior optic capture of intraocular lens in difficult cases of pediatric cataract

We describe the technique of posterior optic capture without anterior vitrectomy in two difficult cases of pediatric cataract. We demonstrate how a three-piece foldable intraocular lens can be maneuvered behind the posterior capsule after an improvised posterior capsulotomy. This technique provided excellent intraocular lens (IOL) stability with the absence of lens epithelial cell proliferation in infants with altered posterior capsule morphology.

Pediatric cataract surgery practices in the COVID-19 era: Perspectives of a tertiary care institute in Northern India

PURPOSE

To discuss the impact of COVID-19 pandemic on the pediatric cataract surgery services in a tertiary care institute in India, as well as the protocol followed for these surgeries.

METHODS

COVID-19 has hampered outpatient and elective services and surgeries throughout the world. During the national lockdown imposed in March in India, outpatient services were suspended in our institute, leading to a tremendous backlog of pediatric patients with cataract. Since the delay in surgery in pediatric cataract can cause amblyopia, our institute had resumed pediatric cataract surgeries in June 2020 at the time of Unlock-1 in the country.

RESULTS

We have discussed the percentage of reduction in pediatric cataract surgeries in 2020 during the Unlock 1, 2, 3, and 4, as compared to the number of surgeries done by the pediatric ophthalmology unit in the same months last year. We had introduced triage and telemedicine in our department. We have discussed the preoperative, intraoperative, and postoperative protocol followed in our institute for children with pediatric cataract, and also the measures which can be taken for the safety of patients and staff.

CONCLUSION

It is essential to ensure COVID-19 protocol, i.e., wearing a mask, social distancing, and frequent hand hygiene, among the patients and health care personnel. Redesigning pediatric cataract surgery practices is essential to ensure the safety of the health care workers and the patients.

Intracameral anesthetic mydriatic (ICAM) assisted pediatric cataract surgery

PURPOSE

To assess the efficacy and safety of intracameral mydriatic and anesthetic combination for pupillary dilation in pediatric cataract surgery.

METHODS

This prospective series included children <12 years, with visually significant unilateral or bilateral cataracts planned for cataract surgery with/without intraocular lens implantation. At the beginning of surgery, 0.025 ml of a combination of phenylephrine hydrochloride (0.31%), tropicamide (0.02%), and lidocaine hydrochloride (1%) was injected intracamerally. The efficacy of the combination was tested by achieving capsulorhexis and intraocular lens implantation without additional mydriatics.

RESULTS

We recruited 13 patients (16 eyes) with a mean age of 4.1 ± 3.9 years. The mean pupillary diameter changed increased from 1.92 to 5.68 mm after injection of one unit (0.025 ml) of drug (p < 0.0001). There was a strong positive correlation of the pupillary dilation with axial length (R = 0.86) and horizontal corneal diameter (R = 0.81). Seventy-five percent patients had a pupillary diameter >6 mm and surgery could be completed successfully in all cases without additional mydriatics. In all cases, pupil dilated as the surgery progressed. No adverse event to the drug was noted.

CONCLUSIONS

Intracameral mydriatic-anesthetic combination is an effective and safe way to obtain stable mydriasis in pediatric cataract surgery.

Performance of a Cantilever Energy Harvester under Harmonic and Random Excitations

The technique of harvesting the energy from base structural vibration through a piezoelectric transducer attached at an appropriate location on the vibrating structure is gaining popularity in recent years. Although the amount of energy harvested depends on the type and magnitude of base excitation, the energy harvest under random excitation as compared to equivalent harmonic excitations is not yet well understood and is investigated in this paper through a cantilever energy harvester. Initially, the energy harvested under harmonic excitations is numerically simulated and experimentally validated under increasing base accelerations with different load resistances. Subsequently, the performance of this energy harvester is experimentally studied under random excitations. The results demonstrate that the harvested energy (a) reaches maximum value when the base excitation matches the natural frequency of the harvester, (b) increases with the increase in base accelerations irrespective of the type of excitation, and (c) increases by 2-14 times under random excitations as compared to equivalent harmonic excitations i.e. under same energy input. It is recommended that the energy harvester be used in aerospace structures where random vibration amplitude is higher, to harvest more energy.