Learning curve of a trained vitreo-retinal surgeon in sub-retinal injections in a rat model: Implications for future clinical trials

Purpose: The sub-retinal injections are not very commonly performed procedures in vitreoretina, but form a crucial step in any cell replacement therapy for retinal diseases. The purpose of this study is to describe the learning curve of a trained vitreo-retinal surgeon in sub-retinal injections in a rat model and its implications in future clinical trials. Methods: This is an in-vivo retrospective animal study using Wistar rats. All ARVO guidelines regarding animal handling were followed. After anesthetization, aspectic preparation and dilating the pupils with 1% tropicamide eye drops, subretinal injection of 10 ?l saline was done via a limbal entry. Data recorded included time taken for the procedure, success of injection, associated complications, post-operative infections and complications. The rats were followed up for 1 month post procedure. A trend analysis was done for the above factors to look for improvement in ease of procedure, reduction in procedure time and reduction in complications for the clinician using a novel objective scale. Results: About 20 eyes were studied. Mean weight of the rats was 188 ± 12.82 gram. Mean time taken for the procedure was 14.1 ± 5.07 minutes. There was a significant inverse co-relation between the serial number of the eye and time taken for the procedure (r = ?0.89, P < 0.0001). Comparative complications noted between the first ten and the last ten eyes were: conjunctival tear 30% versus 10% (P = 0.27), lens touch 50% versus 10% (P = 0.05), subretinal hemorrhage 40% versus 0% (P = 0.13), vitreous loss 30% versus 0% (P = 0.06). The successful subretinal injection without intraocular complications was achieved in 40% versus 90% (P = 0.02). There was a significant co-relation between the serial number of the eye and ease of the procedure (r = 0.87, P < 0.0001). Post operatively none of the eyes had any infection. Six eyes (12%) developed cataract and 3 eyes (6%) had non-resolving retinal detachment at the last examination visit. Conclusion: Subretinal injections in rats have a definite learning curve even for a trained vitreoretinal surgeon. This should be accounted for and resources allocated accordingly to achieve good technical comfort and negate confounding by the surgeon factor in the results of future clinical trials

Prospective study of factors influencing timely versus delayed presentation of preterm babies for retinopathy of prematurity screening at a tertiary eye hospital in India - The Indian Twin Cities ROP Screening (ITCROPS) data base report number 6

Purpose: To evaluate the factors influencing timely versus delayed presentation of preterm babies for ROP evaluation. Methods: Preterm babies (?35 weeks gestational age, ?2000 g birth weight) were prospectively included in the study. Timely presentation was defined as babies who presented for the first ROP screening within 30 days of birth and Delayed as more than 30 days of birth. An event survey to assess factors influencing timely vs delayed presentation was administered to parents/guardian of babies after obtaining informed consent. Results: Data of 278 preterm babies (n = 139 timely vs n = 139 delayed presentation) collected in the event surveys were analyzed. The delayed presenters came at a median duration of 6.3 weeks (1st and 3rd quartiles: 5.3 and 9.1) after birth. The odds of any stage of ROP was 2.6 times and the odds of sight threatening ROP was 6.8 times in those presenting delayed compared to those presenting timely. Major Reasons for delayed presentation were not asked to do so/no referral from pediatrician in 64 (46%) participants and unaware of the importance by 46 (33%) participants. Conclusion: Deviation from screening protocol is an important modifiable risk factor in ROP screening. The study findings suggest the need for creating awareness about timely screening and referral guidelines among the pediatricians involved in “care” of preterm infants at risk of developing ROP.

Barriers to timely presentation for appropriate care of retinopathy of prematurity in Odisha, Eastern India

Purpose: To analyze the causes for late presentation in a series of patients with advanced retinopathy of prematurity (ROP) in a tertiary eye care institute in Eastern India. Methods: We analyzed our medical records and ROP database retrospectively from 2007 to 2015 and prospectively thereafter till 2017 to identify the factors for late presentation in babies with advanced ROP (stages 4 and 5). Results: A total of 71 eligible subjects were analyzed. The mean chronological age was 15.1 months (2 months to 14 years). The three important barriers were: (1) the system and neonatal care policy failure (n = 45; 63.3%), (2) parental negligence and ignorance (n = 19; 26.7%), and (3) ophthalmologist's misdiagnosis or unavailability (n = 7; 10%). Majority of the babies (63.3%) were admitted in the neonatal care unit when they were due for ROP screening with an average duration of stay of 35.5 days. Conclusion: The main barriers to early screening for ROP were related to availability of trained human resources, ignorance of “parents and health care personnel,” and distance from the point of care. This calls for training of ophthalmologists, advocacy with neonatologists and parents, and create systems for better coordination and compliance of the care providers.

Changing patterns of early childhood blinding conditions presenting to a tertiary eye center: The epidemic of retinopathy of prematurity in India

Purpose: Retinopathy of prematurity (ROP) is now emerging as one of the major causes of preventable childhood blindness. The proportion of preterm babies has increased dramatically over the past decade. Our study aims to emphasize the need for ROP screening and management services in these preterm infants. Methods: ICD-coded medical records of children less than 10 years of age presenting to a subspecialty eye hospital from 2000 to 2017 were reviewed. ROP, congenital cataract, congenital glaucoma, and vitamin A deficiency were the most common diagnoses. We evaluated the trend of these diseases from 2000 to 2017. Results: Our data suggested a 20-fold increase in the attendance of children with a diagnosis of ROP who now make over 2% of outpatient children. Vitamin A deficiency has declined over time whereas cataract and glaucoma have remained stable. Conclusion: Our data indicate a need to scale up ROP screening integrated with neonatal care, as well as to build capacity for the treatment of acute and late-stage ROP in India.

Baseline morphological characteristics as predictors of final visual acuity in patients with branch retinal vein occlusions: MARVEL report no. 3

Purpose: To determine the predictive values of baseline optical coherence tomography (OCT) abnormalities on 12-month visual acuity changes in eyes with macular edema (ME) caused by branch retinal vein occlusions (BRVO). Methods: We performed a post hoc analysis of data from 75 participants in the 12-month MARVEL trial. OCT abnormalities at baseline, including ganglion cell layer cystoid spaces (GCL), intraretinal hyper-reflective dots, and central subfield thickness (CST), were correlated with improvements in visual acuity and the number of anti-vascular endothelial growth factor injections required using a multivariate regression model. Results: Eyes with baseline CST > 500 ?m had greater visual gains compared to those with CST <500 ?m (+21.09 vs +16.08 letters, P = 0.04). Eyes with hyper-reflective dots (+13.97 vs +19.93 letters, P = 0.02), and GCL cysts (+9.8 vs +18.9, P = 0.003) had inferior gains in visual acuity. Neurosensory macular detachments at the baseline did not affect gains in visual acuity. Ninety percent of the gain in visual acuity was recorded after two injections and was maintained until month 12. Conclusion: Baseline OCT of <500 ?m, hyper-reflective dots, and GCL cystoid spaces are associated with poorer gains in visual acuity. Most of the visual gain occurs after two injections.

Development of endosulfan tolerant strain of an egg parasitoid Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae).

A strain of T. chilonis, an egg parasitoid of lepidopteran pests tolerant to the most commonly used cyclodiene insecticide--endosulfan was developed in the laboratory. Tolerance to endosulfan was induced by exposing adult parasitoids sequentially from a sub-lethal concentration (0.004%) to the field recommended concentration (0.09%). The strain acquired tolerance to the insecticide after 341 generation of continuous exposure with LC50 values of 1074.96 ppm as compared to LC50 of (70.91 ppm) in susceptible strain. The genetical study showed that F1 crosses exhibited a semi-dominant response to endosulfan with degree of dominance value (D) of 0.58. The resistant factor of tolerant strain was 15.1 folds and of F1 cross were 8.53 folds over susceptible strain. Under net house conditions, the tolerant strain parasitised 56% Helicoverpa armigera eggs on potted cotton plants immediately after an insecticide spray, compared to 3% by the susceptible strain. High percentage survival of the immature stages of the tolerant strain proved their ability to withstand the insecticide load. Breakdown of insecticide tolerance in the strain occurred after four generations in absence of insecticide load. Use of the tolerant strain as a component of bio-intensive IPM in various crops where insecticide use is higher is discussed.

Management of diabetic retinopathy.

Diabetic retinopathy remains a major cause of blindness despite increased understanding of this disease and identification of successful treatments. The Diabetic Retinopathy Study identified risk factors associated with a high risk of blindness and confirmed the benefits of panretinal photocoagulation. The Early Treatment Diabetic Retinopathy Study defined the retinal characteristics, indications of treatment and results of laser treatment of clinically significant macular oedema. The Diabetic Retinopathy Vitrectomy study established the benefits and timing of vitrectomy for non-clearing vitreous haemorrhage and severe proliferative diabetic retinopathy. The Diabetes Control and Complications Trial and the United Kingdom Prospective Diabetes Study have also demonstrated the value of tight control of blood sugar and blood pressure in diabetic retinopathy. These studies developed specific recommendations for the management of diabetic retinopathy. Optimum use of this information can minimize visual loss due to diabetic retinopathy.

Choroidal neovascular membrane.

Choroidal neovascular membrane in the macular area is one of the leading causes of severe visual loss. Usually a manifestation in elderly population, it is often associated with age-related macular degeneration. The current mainstay of management is early diagnosis, usually by fundus examination, aided by angiography and photocoagulation in selected cases. Various other modalities of treatment including surgery are being considered as alternate options, but with limited success. The purpose of this review is to briefly outline the current concepts and the management strategy from a clinician's viewpoint.

Pneumatic retinopexy: principles and practice.

Pneumatic retinopexy (PR) is an alternative to scleral buckling for the surgical repair of selected retinal detachments. A gas bubble is injected into the vitreous cavity, and the patient is positioned so that the bubble closes the retinal break (s), allowing absorption of the subretinal fluid. Cryotherapy or laser photocoagulation is applied around the retinal break(s) to form a permanent seal. The procedure can be done in an outpatient setting, and no incisions are required. A multicenter randomized controlled clinical trial has demonstrated that the anatomic success rate is comparable to scleral buckling, but the morbidity is significantly less with PR. If the macula was detached for less than two weeks, the visual results are significantly better with PR than with scleral buckling. Cataract surgery was required significantly more often following scleral buckling than following PR. Two independent reports have shown that an attempt with PR does not disadvantage the eye; such that the results of scleral buckling after failed PR are not significantly different than primary scleral buckling. A comprehensive review of the world literature on PR revealed 27 statistical series totaling 1,274 eyes. These combined series had a single-operation success rate of 80%, and 98% were cured with reoperations. Pneumatic retinopexy should be considered in cases without inferior or extensive retinal breaks and without significant proliferative vitreoretinopathy. The cost of buckling varies from 4 to 10 times that of PR.

Postsurgical endophthalmitis: diagnosis and management.

Infectious endophthalmitis following intraocular surgery is a complication that could cause severe visual loss or loss of the eye. The categorisation of the event that led to intraocular infection will help the clinician to predict the infectious agent and begin appropriate therapy. Most of the cases of postsurgical endophthalmitis are seen following cataract surgery. It is important for all ophthalmologists, irrespective of specialisation and areas of interest, to be familiar with the management of endophthalmitis. This review briefly describes the facets of clinical and laboratory diagnosis, pathology, and management. While the different viewpoints in the management of endophthalmitis are mentioned in appropriate places, more attention is paid to present a rational approach to the management of endophthalmitis.

Selection of surgical technique for retinal detachment with coloboma of the choroid.

Four eyes with rhegmatogenous retinal detachment and coloboma of the choroid were managed by conventional scleral buckling (one eye); scleral buckling combined with lensectomy, vitrectomy, and fluid-air exchange (two eyes); and vitrectomy, silicone oil injection without scleral buckling (one eye). Retinal break was seen within the coloboma in two eyes, at the periphery in one eye, and, both in the coloboma and periphery in one eye. At a follow-up of 15 months, the retina was found attached in all the patients. The success of these surgical procedures could be attributed to careful preoperative/intraoperative fundus examination and individualised surgical planning.