Intraocular lens formula calculation in pediatric eyes: Do we have an answer? A retrospective comparison between Sanders-Retzlaff-Kraff II and Barret's formula.

Purpose: The ideal formula for intraocular lens (IOL) power calculation following cataract surgery in pediatric eyes till date has no answer. We compared the predictability of the Sanders-Retzlaff-Kraff (SRK) II and the Barrett Universal (BU) II formula and the effect of axial length, keratometry, and age. Methods: This was a retrospective analysis of children who were under eight years of age and who underwent cataract surgery with IOL implantation under general anesthesia between September 2018 and July 2019. The prediction error of SRK II formula was calculated by subtracting the target refraction and the actual postoperative spherical equivalent. Preoperative biometry values were used to calculate the IOL power using the BU II formula with the same target refraction that was used in SRK II. The predicted spherical equivalent of the BU II formula was then back-calculated using the SRK II formula with the IOL power obtained with the BU II formula. The prediction errors of the two formulae were compared for statistical significance. Results: Seventy-two eyes of 39 patients were included in the study. The mean age at surgery was 3.8 ± 2 years. The mean axial length was 22.1 ± 1.5 mm, and the mean keratometry was 44.7 ± 1.7 D. The group with an axial length >24 mm showed a significant and strong positive correlation (r = 0.93, P = 0) on comparison mean absolute prediction errors using the SRK II formula. There was a strong negative correlation between the mean prediction error in the overall keratometry group using the BU II formula (r = -0.72, P < 0.000). There was no significant correlation between age and refractive accuracy using the two formulae in any of the subgroups of age. Conclusion: There is no perfect answer to an ideal formula for IOL calculation in children. IOL formulae need to be chosen keeping in mind the varying ocular parameters.

Pediatric ocular motor cranial nerve palsy: Demographics and etiological profile.

Purpose: The aim of this study was to describe epidemiological and clinical characteristics of pediatric ocular motor cranial nerve palsy. Methods: This was a retrospective record-based study, carried out at a tertiary eye care hospital in India, between January 2011 and January 2015 and included patients up to 16 years of age at the time of presentation, diagnosed with third, fourth, sixth nerve palsy or a combination of these with other cranial nerve palsy. Data analyzed included demographic details, etiologies, presence or absence of amblyopia, relevant investigations, and management. Results: A total of 90 cases were included in the study. Eighty patients (88.88%) presented with isolated nerve palsy. Forty-three patients (47.77%) had congenital nerve palsy. The most common nerve involved was third (n = 35, 38.88%) followed by sixth (n = 23, 25.55%) and fourth nerve (n = 22, 24.44%). Most common cause of third and fourth cranial nerve palsy was congenital (n = 18, 51.42% and n = 17, 77.30%, respectively), while it was trauma for the sixth nerve (n = 7, 30.40%). Amblyopia was most frequently associated with third cranial nerve palsy (n = 27, 77.14%). The radio-imaging yield was maximum (n = 7, 70%) for combined cranial nerve palsy. Overall 44 (48.88%) patients were managed conservatively, while 46 (51.11%) patients needed squint with or without ptosis surgery. Conclusion: The most common ocular motor cranial nerve involved in the pediatric population was the third cranial nerve, and it was found to be the most amblyogenic in this age group. The neuroimaging yield was maximum for combined cranial nerve palsy. The most common conservatively managed nerve palsy in this study group was the fourth nerve palsy.

A comparison of cycloplegic autorefraction and retinoscopy in Indian children.

BACKGROUND: Correction of significant refractive errors in childhood helps in preventing amblyopia and strabismus. India has a huge demand for eye-care services related to uncorrected refractive errors with limited manpower resources. This can be overcome by autorefractors, which are free of operator bias, do not need skilled eye-care professionals and can be operated with ease. Hence, the purpose of this study, the first in the Indian population, was to determine the accuracy of autorefraction compared to traditional retinoscopy under cycloplegia. METHOD: A cross-sectional study of all children meeting our inclusion criteria was conducted from July till October 2011 in a tertiary eye care centre. Children underwent cycloplegic (cyclopentolate plus tropicamide) refraction with an auto-refractometer (Topcon KR-8900) and traditional retinoscopy and the results were compared. Patients were divided into three groups: Group 1: Myopia and myopic astigmatism, Group 2: Hyperopia and hyperopic astigmatism and Group 3: Mixed astigmatism. Clinically significant difference was defined as either of more than 0.50 D difference in sphere, more than 0.5 D difference in cylinder or more than 20 degrees difference in axis. RESULTS: The left eyes of 294 children (148 male) were included in the study. Mean age was 8.22 ± 3.47 years. Clinically significant differences were noted in 13.22 per cent of eyes in Group 1, 15.09 per cent of eyes in Group 2 and 20.90 per cent of eyes in Group 3. Clinically significant differences were more common in children aged less than six years (25 per cent) compared to older children (9.19 per cent). Comparing the sphere, cylinder, spherical equivalent and length of power vector values gained by autorefraction and retinoscopy, no statistically significant differences were found in any group. CONCLUSION: Autorefraction with Topcon KR-8900 can be used reliably in Indian children older than six years, if conducted under cycloplegia. In mixed astigmatism and children less than six years, it should be corroborated with retinoscopy.

Surgical treatment of familial absence of the inferior rectus muscle.

Familial inferior rectus muscle aplasia is rare. Patients with this condition require surgery to correct hypertropia and anomalous head posture. We report successful surgical outcomes in a father with bilateral and his 2 children with unilateral absent inferior rectus muscle, all 3 of whom were diagnosed preoperatively by imaging.

An unusual intraocular tongue worm in anterior chamber: a case report.

PURPOSE: To present an interesting case of intraocular Linguatula serrata in a 5-year-old boy. DESIGN: Case report. METHODS: Visual acuity testing, biomicroscopic slit-lamp examination, and indirect ophthalmoscopy were performed on a 5-year-old boy with a progressively enlarging white lesion in the anterior chamber of the right eye. RESULTS: The worm was found in the anterior chamber, attached firmly to the peripheral iris with free-floating tail. The living worm, which grew progressively over 2 months, caused a mild anterior chamber reaction with marginally raised intraocular pressure. The worm was removed surgically in toto. This is the first documentation of human ocular pentastomiasis in India. CONCLUSIONS: An adult worm in the anterior chamber is apparently rare and can present even with a quiet eye. Surgical removal is essential. However, visual prognosis is good.

Large-angle strabismus: can a single surgical procedure achieve a successful outcome?

PURPOSE: Large-angle strabismus is a gray zone for surgeons with various advocates for one, two-, three-, or even four-muscle surgeries. Very frequently, reoperations are required in these cases in order to achieve a successful outcome. In this article, the authors evaluate the outcome of concomitant large-angle strabismus after a single surgical procedure. METHODS: A retrospective analysis of all operated cases of concomitant large-angle strabismus (50 prism diopters or more) during a 1.5-year period was performed from patient's case files. A successful outcome of surgery was defined as deviation within 10 prism diopters of orthophoria/tropia for both distance and near. RESULTS: Fifty patients met the inclusion criteria. The overall success rate was 60%, with the esotropia group having a higher success rate (68.75%) than the exotropia group (44.45%). Ten patients underwent recess-resect procedure, 20 had bimedial rectus recession, and 3 had bilateral lateral rectus recession, while 17 patients had surgery on 3 horizontal rectus muscles. Thirty-three patients had two-muscle surgery with a success rate of 57.58%, while 17 patients had three-muscle surgery with a success rate of 64.71%, the difference being statistically insignificant. There was no statistically significant difference between the various age groups analyzed for overall success rate, suggesting that age group is not a factor for positive outcome in large-angle strabismus surgery. A total of 12 patients were amblyopic at the time of strabismus surgery and they had a success rate of 33.33%, which was much poorer than the success rate (68.42%) of the remaining 38 patients who did not have amblyopia at the time of surgery. CONCLUSIONS: A good surgical outcome can be obtained in large-angle strabismus with a single surgical procedure, though a randomized controlled study needs to be done to establish whether three-muscle surgeries give better results than two-muscle surgeries.

Performing combined strabismus and cataract surgery: an effective approach in selected cases.

PURPOSE: In the presence of both strabismus and cataract, it is always a dilemma whether to manage them separately or together. In this paper, the authors evaluate the results of combined strabismus and cataract surgery. METHODS: The records of 50 patients were reviewed retrospectively. They were divided into two groups: those who developed strabismus first and cataract later (group 1, n = 17 patients) and those who developed cataract first and strabismus later (group 2, n = 33 patients). RESULTS: Motor alignment (less than 10 prism diopters) was achieved in 35.3% in group 1 and 75.8% in group 2. Visual success (20/40 or better) was attained in 70.6% in group 1 and 57.6% in group 2. In group 1, when the angle of deviation was more than 80 prism diopters, poor motor alignment was achieved (25%). CONCLUSION: Surgical success after one operation was achieved in the majority of all eyes that had combined surgery. In selected cases, combined strabismus and cataract surgery is a safe and effective procedure, optimizing the alignment of the visual axes, improving visual acuity, and minimizing the need for additional procedures.

Role of ultrasound biomicroscopy (UBM) in the detection and localisation of anterior segment foreign bodies.

INTRODUCTION: The aim of this study was to investigate the role of ultrasound biomicroscopy (UBM) in imaging anterior segment foreign bodies and compare it with conventional B-scan ultrasound and computed tomography (CT). MATERIALS AND METHODS: The charts of 18 eyes with anterior segment foreign bodies were reviewed. The rates of detection of foreign bodies using ultrasound, CT scan and UBM were compared. RESULTS: The foreign body detection rates were 36.5% by ultrasound, 88.9% by CT scan, and 94.4% by UBM. The diagnosis of presence of a foreign body using UBM was made based on high reflective echoes causing shadowing or reverberations. In 7 eyes, UBM detected injury to the zonules, guiding the operative procedure. In the 8 eyes for which all tests were performed, rates of detection of foreign bodies were 25% (2/8) with ultrasound, 87.5% (7/8) with CT, and 100% (8/8) with UBM. CONCLUSION: UBM is a valuable adjunct for the accurate localisation of small foreign bodies, including cilia. It offers a higher detection rate than that provided by ultrasound and CT scan.

Theoretical study of chlorine nitrates: implications for stratospheric chlorine chemistry.

Reported here is a theoretical study of possible stratospheric chlorine reservoir species including isomers of chemical formula ClNO(4) and ClNO(5), in addition to the well-known ClONO(2) reservoir species. Density functional theory (DFT) in conjunction with large one-particle basis sets has been used to determine equilibrium structures, dipole moments, rotational constants, harmonic vibrational frequencies, and infrared intensities. The B3LYP functional was used since it has previously been shown to perform well for similar compounds. The equilibrium geometry and vibrational spectra of ClONO(2) are shown to be in good agreement with the experimental data and also with high-level coupled-cluster calculations reported previously. Three stable isomers have been identified for each ClNO(4) and ClNO(5). The vibrational spectrum of O(2)ClONO(2) has been compared with the available experimental data and found to be in good agreement. The relative energetics of the ClNO(4) and ClNO(5) isomers have been determined using large atomic natural orbital (ANO) basis sets in conjunction with the singles and doubles coupled-cluster method that includes a perturbational correction for triple excitations, denoted CCSD(T). Accurate heats of formation have been evaluated by computing energies for isodesmic reactions involving the ClNO(4) and ClNO(5) isomers. The stability of these molecules with respect to thermal dissociation is examined. The present study suggests that isomers of ClNO(4) and ClNO(5) may have no atmospheric chemical relevance because the atmospheric concentrations of the necessary reactants are insufficient, but it is also found that under laboratory conditions the formation of O(2)ClONO(2) cannot be ignored.