Biodegradable material for glaucoma drainage devices - A pilot study in rabbits.

PURPOSE: To study the morphological and histological characteristics of the fibrous capsule formed around a novel biodegradable glaucoma drainage device (GDD) implant made of oxidized regenerated cellulose (ORC) after 1 and 3 months of its implantation. METHODS: It was a prospective, interventional, preclinical experimental study using New Zealand white rabbits. All animals underwent GDD implantation with a novel biodegradable device. The device's body was made of ORC and attached to a silicone tube, connecting the body to the anterior chamber. Histopathology (hematoxylin and eosin/Masson's trichrome staining) and immunohistochemistry (Alpha-Smooth Muscle Actin expression) characteristics of the bleb formed around the novel device were noted at 1 and 3 months. RESULTS: One month post implantation, the biodegradable material produced a significant foreign body type of reaction evidenced by the exuberant infiltration by macrophages, lymphocytes, and multinucleated giant cells. The granulomatous response subsided by 3 months with disorganized collagen deposition on Masson's trichrome staining. The silicone tube was an internal control, and histopathology demonstrated well-organized collagen deposition around it at 3 months. Immunohistochemistry for α-smooth muscle actin also demonstrated more myofibroblast transformation at the site of the tube than the biodegradable implant. CONCLUSIONS: Our results indicate that the tissue response around a biodegradable GDD was different from the response to conventional devices. A diffuse, loose vascularized mesh was observed to develop, which may be more compatible with sustained IOP control over a longer period, in contrast to the usual thick and dense capsule formed around the non-biodegradable devices.

Cataract surgery in children using intracameral mydriatic.

PURPOSE: To study the pupil dynamics with premixed intracameral anesthetic mydriatic combination of phenylephrine (0.31%), tropicamide (0.02%), and lidocaine (1%) in pediatric cataract surgery. METHODS: Consecutive children aged ≤12 years planned for cataract surgery were recruited. A commercially available premixed combination of phenylephrine (0.31%), tropicamide (0.02%), and lidocaine (1%) was injected at the beginning of surgery without any topical/infusion drugs for mydriasis. Pupil sizes at various points of surgery were studied. RESULTS: We recruited 75 patients with a mean age of 24.3 ± 33.4 months (range: 1 month-11 years). Adequate mydriasis with a single injection was achieved in 93.5% (n = 73 eyes of 70 patients) without additional pharmacotherapy or intervention. The mean pupillary diameter increased from 1.8 ± 0.79 to 6.1 ± 1.4 mm after injection (mean change of 4.2 ± 1.25 mm from baseline). The mean variability in pupillary diameter was 0.73 ± 1.3 mm. In five eyes, good dilatation was not possible even after repeat injection. CONCLUSION: Fixed-dose premixed intracameral injection is effective in pupil dilatation. It alleviates the need for any topical dilators or additional intraoperative supplementation for pediatric cataract surgery.

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.

Pharmacological management of intra-operative miosis during cataract surgery.

Cataract surgery requires a well-dilated and stable pupil for a good outcome. Unexpected pupillary constriction during surgery increases the risk of complication. This problem is more pronounced in children. There are now pharmacological interventions that help tackle this unforeseen happening. Our review discusses the simple and quick options available to a cataract surgeon when faced with this dilemma. As cataract surgical techniques continue to improvise and get faster, an adequate pupil size is of paramount importance. Various topical and intra-cameral drugs are used in combination to achieve mydriasis. Despite good pre-operative dilation, the pupil can be quite unpredictable during surgery. Intra-operative miosis limits the field of surgery and increases the risk of complications. For example, if the pupil size decreases from 7 mm to 6 mm, this 1 mm change in pupil diameter will lead to a decrease of 10.2 mm2 in the area of surgical field. Making a good capsulorhexis with a small pupil can be a challenge, even for an experienced surgeon. Repeated touching of the iris increases the risk of fibrinous complications. Removal of cataract and the cortical matter becomes increasingly difficult. Intra-ocular lens implantation in the bag also requires adequate dilation. When dealing with challenging cases like lens subluxation, pseudo-exfoliation, and zonular dehiscence, a small pupil further increases the risk and adversely affects the surgical outcome. Hence, achieving and maintaining adequate mydriasis throughout surgery is essential. This review highlights the risk factors for small pupils during surgery and current management strategies.

Comprehensive review of amblyopia: Types and management.

The optimal method of treatment for a child depends on the patient's age at the time of diagnosis, the onset and type of amblyopia, and the degree of compliance attainable. In deprivation amblyopia, the cause of visual impairment (e.g., cataract, ptosis) needs to be treated first, and then the disorder can be treated such as other types of amblyopia. Anisometropic amblyopia needs glasses first. In strabismic amblyopia, conventionally amblyopia should be treated first, and then strabismus corrected. Correction of strabismus will have little if any effect on the amblyopia, although the timing of surgery is controversial. Best outcomes are achieved if amblyopia is treated before the age of 7 years. The earlier the treatment, the more efficacious it is. In selected cases of bilateral amblyopia, the more defective eye must be given a competitive advantage over the comparatively good eye. Glasses alone can work when a refractive component is present, but occlusion might make the glasses work faster. The gold standard therapy for amblyopia remains occlusion of the better eye although penalization is also evidenced to achieve equal results. Pharmacotherapy has been shown to achieve suboptimal outcomes. Newer monocular and binocular therapies based on neural tasks and games are adjuncts to patching and can also be used in adults.

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.

Role of swept-source anterior segment optical coherence tomography in imaging pediatric cataract.

Purpose: To determine the morphology of pediatric cataracts and assess the status of the anterior and posterior capsules preoperatively on swept-source anterior segment optical coherence tomography (ASOCT) and compare the findings to those of intraoperative examination. Secondly, we aimed to obtain biometric measurements on ASOCT and compare them to those obtained on A-scan/optical methods. Methods: This was a prospective and observational study carried out at a tertiary care referral institute. ASOCT scans for anterior segment were obtained preoperatively for all patients, aged <8 years, scheduled for paediatric cataract surgery. The morphology of the lens and capsule and biometry were performed on ASOCT and the same were assessed intraoperatively. The main outcome measures were comparison of ASOCT findings to intraoperative findings. Results: The study included 33 eyes of 29 patients (range 3 months-8 years). The morphological characterization of cataract on ASOCT was accurate in 31/33 (94%) cases. ASOCT accurately identified fibrosis and rupture of the anterior and posterior capsules in 32/33 (97%) cases each. In 30% of eyes, ASOCT gave additional information preoperatively compared to the slit lamp. Intraclass correlation coefficient (ICC) calculation revealed a good agreement between the keratometry values obtained on ASOCT and those obtained preoperatively with a handheld/optical keratometer (ICC = 0.86, P = 0.001). Conclusion: ASOCT is a valuable tool that could provide complete preoperative information of the lens and capsule in pediatric cataract cases. In children as young as 3 months of age, intraoperative risks and surprises could be diminished. The keratometric readings are highly dependent on patient cooperation but show good agreement with the handheld/optical keratometer readings.

Spectrum of congenital and inherited ocular disorders seen in a genetic clinic: Experience of a developing ocular genetic service.

Purpose: Hereditary causes are an important etiological category of childhood blindness. This study reports the real-world experience of a developing ocular genetic service. Methods: The study was carried out from Jan 2020 to Dec 2021 jointly by the Pediatric Genetic Clinic and the Department of Ophthalmology of a tertiary care hospital in North-West India. Children presenting to the genetic clinic with congenital or late-onset ocular disorder(s) and any individual (irrespective of age) suffering from an ophthalmic disorder and referred by an ophthalmologist for genetic counseling for himself/herself and/or his/her family member(s) were included. Genetic testing (exome sequencing/panel-based sequencing/chromosomal microarray) was outsourced to third-party laboratories with the cost of the test being borne by the patient. Results: Exactly 8.6% of the registered patients in the genetic clinic had ocular disorders. Maximum number of patients belonged to the category of anterior segment dysgenesis, followed by microphthalmia anophthalmia coloboma spectrum, lens disorders, and inherited retinal disorders in decreasing numbers. The ratio of syndromic ocular to isolated ocular disorders seen was 1.8:1. Genetic testing was accepted by 55.5% of families. The genetic testing was clinically useful for ~35% of the tested cohort, with the opportunity for prenatal diagnosis being the most useful application of genetic testing. Conclusion: Syndromic ocular disorders are seen at a higher frequency compared to isolated ocular disorders in a genetic clinic. Opportunity for prenatal diagnosis is the most useful application of genetic testing in ocular disorders.

Primary aphakia: clinical recognition is the key to diagnosis.

PURPOSE: To describe the presentation and treatment outcomes of a cohort of children with primary aphakia (PA). METHODS: Clinical photographs and ultrasound biomicroscopy (UBM) images of children presenting with sclerocornea and undetermined anterior segment dysgenesis between July 2017 and December 2020 were reviewed retrospectively. Children who had no crystalline lens visible on UBM were included. RESULTS: A total of 124 UBM images were captured for 124 children with cloudy corneas. Twelve children were identified with congenital primary aphakia: 5 had bilateral buphthalmos, 2 had buphthalmos in one eye and microphthalmos in the other, and 5 had bilateral sclerocornea-microphthalmia complex. All patients had a peculiar silvery-blue corneal appearance, with fine vascularization on the corneal surface. The overall corneal thickness was 409.1 ± 8.7 µm. The intraocular pressure (IOP) in eyes with glaucoma was 24.5 ± 7.3 mm Hg; in microphthalmic eyes, 11.4 ± 3.4 mm Hg (P <0.001). The raised IOP was treated with limited trans-scleral cyclophotocoagulation under transillumination and topical antiglaucoma medications. Children with glaucoma gained ambulatory vision with spectacles. CONCLUSIONS: Congenital primary aphakia has a characteristic clinical appearance and may present as buphthalmos or microphthalmos, depending on the extent of dysgenesis. Incisional surgery may result in phthisis because of ciliary body dysgenesis and unpredictable aqueous production.