Ashik Mohamed

Clinical Outcomes of Penetrating Keratoplasty After Autologous Cultivated Limbal Epithelial Transplantation for Ocular Surface Burns

PURPOSE To report the clinical outcomes of penetrating keratoplasty (PK) after autologous cultivated limbal epithelial transplantation in eyes with limbal stem cell deficiency (LSCD) after ocular surface burns. DESIGN Retrospective case series. METHODS This study included 47 patients with unilateral LSCD treated by autologous cultivated limbal epithelial transplantation and PK between 2001 and 2010. PK was performed either along with (single-stage; n = 12) or at least 6 weeks after (2-stage; n = 35) limbal transplantation. The primary outcome measure was corneal allograft survival, and failure was defined clinically as loss of central graft clarity. Secondary outcomes were postoperative Snellen visual acuity and complications. RESULTS Most patients were young (mean age, 18 ± 11.4 years) males (76.6%) with LSCD resulting from alkali burns (78.7%) and with visual acuity less than 20/200 (91.5%). The mean follow-up was 4.2 ± 1.9 years. Kaplan-Meier corneal allograft survival rate at 1 year was significantly greater in eyes undergoing 2-stage limbal and corneal transplantation (80 ± 6%; median survival, 4 years) compared with single-stage limbal and corneal transplantation (25 ± 13%; median survival, 6 months; P = .0003). Visual acuity of 20/40 or better was attained by 71.4% of eyes with clear corneal grafts. Allograft failure occurred in 26 (60.5%) eyes as a result of graft rejection (57.7%), graft infiltrate (26.9%), or persistent epithelial defects (15.4%). Recurrence of LSCD was more common after single-stage (58.3%) than 2-stage (14.3%) surgery (P = .008). CONCLUSIONS The 2-stage approach of autologous cultivated limbal epithelial transplantation followed by PK successfully restores ocular surface stability and vision in eyes with chronic ocular burns. The single-stage approach is associated with poorer clinical outcomes and should be avoided.

Autophagy and mitophagy participate in ocular lens organelle degradation

The eye lens consists of a layer of epithelial cells that overlay a series of differentiating fiber cells that upon maturation lose their mitochondria, nuclei and other organelles. Lens transparency relies on the metabolic function of mitochondria contained in the lens epithelial cells and in the immature fiber cells and the programmed degradation of mitochondria and other organelles occurring upon lens fiber cell maturation. Loss of lens mitochondrial function in the epithelium or failure to degrade mitochondria and other organelles in lens fiber cells results in lens cataract formation. To date, the mechanisms that govern the maintenance of mitochondria in the lens and the degradation of mitochondria during programmed lens fiber cell maturation have not been fully elucidated. Here, we demonstrate using electron microscopy and dual-label confocal imaging the presence of autophagic vesicles containing mitochondria in lens epithelial cells, immature lens fiber cells and during early stages of lens fiber cell differentiation. We also show that mitophagy is induced in primary lens epithelial cells upon serum starvation. These data provide evidence that autophagy occurs throughout the lens and that mitophagy functions in the lens to remove damaged mitochondria from the lens epithelium and to degrade mitochondria in the differentiating lens fiber cells for lens development. The results provide a novel mechanism for how mitochondria are maintained to preserve lens metabolic function and how mitochondria are degraded upon lens fiber cell maturation.

Age-dependence of the optomechanical responses of ex vivo human lenses from India and the USA, and the force required to produce these in a lens stretcher: the similarity to in vivo disaccommodation

The purpose of this study was to study the age-dependence of the optomechanical properties of human lenses during simulated disaccommodation in a mechanical lens stretcher, designed to determine accommodative forces as a function of stretch distance, to compare the results with in vivo disaccommodation and to examine whether differences exist between eyes harvested in the USA and India. Postmortem human eyes obtained in the USA (n=46, age=6-83 years) and India (n=91, age=1 day-85 years) were mounted in an optomechanical lens stretching system and dissected to expose the lens complete with its accommodating framework, including zonules, ciliary body, anterior vitreous and a segmented rim of sclera. Disaccommodation was simulated through radial stretching of the sectioned globe by 2mm in increments of 0.25 mm. The load, inner ciliary ring diameter, lens equatorial diameter, central thickness and power were measured at each step. Changes in these parameters were examined as a function of age, as were the dimension/load and power/load responses. Unstretched lens diameter and thickness increased over the whole age range examined and were indistinguishable from those of in vivo lenses as well as those of in vitro lenses freed from zonular attachments. Stretching increased the diameter and decreased the thickness in all lenses examined but the amount of change decreased with age. Unstretched lens power decreased with age and the accommodative amplitude decreased to zero by age 45-50. The load required to produce maximum stretch was independent of age (median 80 mN) whereas the change in lens diameter and power per unit load decreased significantly with age. The age related changes in the properties of human lenses, as observed in the lens stretching device, are similar to those observed in vivo and are consistent with the classical Helmholtz theory of accommodation. The response of lens diameter and power to disaccommodative (stretching) forces decreases with age, consistent with lens nuclear stiffening.

Clinical manifestations of congenital aniridia.

PURPOSE To study the various clinical manifestations associated with congenital aniridia in an Indian population. METHODS In this retrospective, consecutive, observational case series, all patients with the diagnosis of congenital aniridia seen at the institute from January 2005 to December 2010 were reviewed. In all patients, the demographic profile, visual acuity, and associated systemic and ocular manifestations were studied. RESULTS The study included 262 eyes of 131 patients with congenital aniridia. Median patient age at the time of initial visit was 8 years (range: 1 day to 73 years). Most cases were sporadic and none of the patients had parents afflicted with aniridia. The most common anterior segment abnormality identified was lenticular changes. Cataract was the predominant lens finding, observed in 93 of 231 (40.3%) phakic eyes. Other lens abnormalities were subluxation, coloboma, posterior lenticonus, and microspherophakia. Corneal involvement of varying degrees was seen in 157 of 262 (59.9%) eyes, glaucoma was identified in 95 of 262 (36.3%) eyes, and foveal hypoplasia could be assessed in 230 of 262 (87.7%) eyes. Median age when glaucoma and cataract were noted was 7 and 14 years, respectively. None of the patients had Wilms tumor. CONCLUSIONS Congenital aniridia was commonly associated with classically described ocular features. However, systemic associations were characteristically absent in this population. Notably, cataract and glaucoma were seen at an early age. This warrants a careful evaluation and periodic follow-up in these patients for timely identification and appropriate management.

Outcomes of Descemet's stripping endothelial keratoplasty in eyes with failed therapeutic penetrating keratoplasty.

Purpose:  To report the results of Descemet’s stripping endothelial keratoplasty (DSEK) for failed therapeutic penetrating keratoplasty (PK).

Growth of the human lens in the Indian adult population: Preliminary observations

Context: The eye lens grows throughout life by the addition of new cells inside the surrounding capsule. How this growth affects the properties of the lens is essential for understanding disorders such as cataract and presbyopia. Aims: To examine growth of the human lens in the Indian population and compare this with the growth in Western populations by measuring in vitro dimensions together with wet and dry weights. Settings and Design: The study was conducted at the research wing of a tertiary eye care center in South India and the study design was prospective. Materials and Methods: Lenses were removed from eye bank eyes and their dimensions measured with a digital caliper. They were then carefully blotted dry and weighed before being placed in 5% buffered formalin. After 1 week fixation, the lenses were dried at 80 °C until constant weight was achieved. The constant weight was noted as the dry weight of the lens. Statistical Analysis Used: Lens parameters were analyzed as a function of age using linear and logarithmic regression methods. Results: Data were obtained for 251 lenses, aged 16–93 years, within a median postmortem time of 22 h. Both wet and dry weights increased linearly at 1.24 and 0.44 mg/year, respectively, throughout adult life. The dimensions also increased continuously throughout this time. Conclusions: Over the age range examined, lens growth in the Indian population is very similar to that in Western populations.

Electron tomography of fiber cell cytoplasm and dense cores of multilamellar bodies from human age-related nuclear cataracts.

Human nuclear cataract formation is a multi-factorial disease with contributions to light scattering from many cellular sources that change their scattering properties over decades. The aging process produces aggregation of cytoplasmic crystallin proteins, which alters the protein packing and texture of the cytoplasm. Previous studies of the cytoplasmic texture quantified increases in density fluctuations in protein packing and theoretically predicted the corresponding scattering. Multilamellar bodies (MLBs) are large particles with a core of crystallin cytoplasm that have been suggested to be major sources of scattering in human nuclei. The core has been shown to condense over time such that the refractive index increases compared to the adjacent aged and textured cytoplasm. Electron tomography is used here to visualize the 3D arrangement of protein aggregates in aged and cataractous lens nuclear cytoplasm compared to the dense protein packing in the cores of MLBs. Thin sections, 70 nm thick, were prepared from epoxy-embedded human transparent donor lenses and nuclear cataracts. Tilt series were collected on an FEI T20 transmission electron microscope (TEM) operated at 200 kV using 15 nm gold particles as fiducial markers. Images were aligned and corrected with FEI software and reconstructed with IMOD and other software packages to produce animated tilt series and stereo anaglyphs. The 3D views of protein density showed the relatively uniform packing of proteins in aged transparent lens nuclear cytoplasm and less dense packing of aged cataractous cytoplasm where many low-density regions can be appreciated in the absence of the TEM projection artifacts. In contrast the cores of the MLBs showed a dense packing of protein with minimal density fluctuations. These observations support the conclusion that, during the nuclear cataract formation, alterations in protein packing are extensive and can result in pronounced density fluctuations. Aging causes the MLB cores to become increasingly different in their protein packing from the adjacent cytoplasm. These results support the hypothesis that the MLBs increase their scattering with age and nuclear cataract formation.

EVALUATION OF PROTEIN-ENERGY WASTING AND INFLAMMATION ON PATIENTS UNDERGOING CONTINUOUS AMBULATORY PERITONEAL DIALYSIS AND ITS CORRELATIONS

Background: Protein-energy wasting (PEW) and heightened inflammation are prevalent in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) and is a strong risk factor for morbidity and mortality in these patients. Evaluation of PEW, prevalence of inflammation as well as interrelationship between various nutritional indices and inflammation has not been studied in much detail in patients undergoing CAPD. Objectives: This study was conducted to evaluate the interrelationship between PEW and inflammation in patients undergoing CAPD. Patients and Methods: Sixty-three patients undergoing CAPD (M = 28, F = 35) were assessed with regard to their nutritional status and inflammation after a minimum of 3 months CAPD initiation. Nutritional status was assessed by dietary diary, anthropometry, subjective global assessment, and multifrequency bioelectrical impedance analysis (BIA). In addition, their serum albumin, prealbumin, transferrin, and cholesterol level were measured. Also, inflammation in these patients was assessed by High-Sensitivity C-Reactive Protein (hs-CRP > 3 mg/L) and Interleukin-6 (IL-6 > 2 µg/mL). Later on, diagnosis of malnutrition was made based on different methods. Correlation between inflammation and various nutritional assessment indices were analyzed statistically. Results: Mean (SD) age of the patients was 57.6 (11.6) years. The average (SD) calorie and protein intake per day were 25.5 (4.6) kcal and 0.81 (0.2) mg, respectively. The mean and standard deviation of anthropometry variables of body mass index (BMI), mid-arm circumference (MAC), tricipital skin-fold thickness (TST), mid-arm muscle circumference (MAMC), and corrected mid-arm muscle area (cMAMA) were 23.7 ± 5 kg/m2, 26.3 ± 4.5 cm, 1.624 ± 0.4 cm, 25.6 ± 4.5 cm, and 45.7 ± 19.7 cm2, respectively. The mean values of serum protein, albumin, prealbumin, transferrin, cholesterol, triglyceride, hs-CRP, and IL-6 were 5.9 g/dL, 3.0 g/dL, 21.11 mg/dL, 130.6 mg/dL, 155.9 mg/dL, 136.1 mg/dL, 8.8 ± 7.6 mg/L, and 8.4 ± 12.2 µg/dL, respectively. Based on subjective global assessment (SGA); 11.63 (17.4%), 34.63 (54%), and 18.65 (28.6%) patients undergoing CAPD had normal, moderate, and severe malnutrition status, respectively. According to serum albumin level; 13.63 (21%), 39.63 (62%), and 11.63 (17%) patients undergoing CAPD had normal, moderate, and severe malnutrition status, respectively. Finally, based on BMI; 33.63 (52%), 23.63 (37%), and 7.63 (11%) patients undergoing CAPD had normal, moderate, and severe malnutrition status, respectively. About 76.1% and 9.5% of patients undergoing CAPD were malnourished based on lean tissue index (LTI) and fat tissue index (FTI), respectively. Based on hs-CRP and IL-6 findings, 70% (44/63) and 71.8% (45/63) of patients undergoing CAPD had high inflammation, respectively. High sensitive C-reactive protein correlated negatively (significantly) with serum albumin, prealbumin, and transferrin. Interleukin -6 correlated negatively (significantly) with MAC; MAMA; serum albumin, cholesterol, and transferrin. There was significant positive correlation between hs-CRP and IL-6. There is statistically significant difference in total protein intake (g/d), protein intake (g/kg/d), serum protein (g/dL), albumin (g/dL), transferrin (mg/dL), and cholesterol (mg/dL) between patients with and without inflammation. Conclusions: Protein-energy wasting (80% - 85%) by various methods and inflammation (70%) was very prevalent among patients undergoing CAPD. Inflammatory markers show significant negative correlation with anthropometry and serological markers. Inflammatory markers are suggested to be included in the regular assessment of patients undergoing CAPD, for the better management of protein-energy wasting.

Post Cardiac Surgery Acute Kidney Injury: A Woebegone Status Rejuvenated by the Novel Biomarkers

Background: Acute kidney injury (AKI) is common after cardiac surgery, the incidence varying between 7.7% and 28.1%. It significantly increases morbidity and mortality. Creatinine considerably delays the diagnosis with its own attended demerits. Novel urinary biomarkers are emerging which help in rapid diagnosis thus reducing the morbidity and mortality. Biomarkers of our study were neutrophil gelatinase-associated lipocalin (NGAL) and Interleukin-18 (IL-18). Objectives: To find out the incidence of AKI in post-cardiac surgery patients in our hospital, the ability of the two biomarkers in early diagnosis in predicting the severity of AKI based on RIFLE’s criteria and their ability to discriminate pre-renal from intrinsic AKI. Patients and Methods: One-hundred patients who underwent cardiac surgery were selected. Midstream urine samples were collected at 3 time intervals (baseline before surgery, 24 hours and 7 days after surgery). Biomarkers were measured by ELISA using BIORAD processors. Fractional excretion of sodium and urea were used to discriminate pre-renal from intrinsic AKI. Results: Out of 100 patients, 31 had AKI, 11 being pre-renal and 20 intrinsic AKI. Four patients required renal replacement therapy (12.9% among AKI cases and 4% in the overall study cohort). Four among 31 expired in intensive care unit. Identifiable risk factors for AKI included insulin requiring diabetes mellitus, chronic obstructive pulmonary disease, increased cardio-pulmonary bypass time, combined valvular surgery and coronary artery bypass grafting, employment of intra-aortic balloon counter pulsation, left main coronary artery occlusion and an ejection fraction of < 40%. NGAL was extremely sensitive (area under curve-0.96) in detecting intrinsic AKI at 24 hours followed by IL-18 ratio with an area under curve of 0.89. Creatinine at 24 hours was able to detect only 31.6% of intrinsic AKI. None of the pre-renal cases showed rise in the urinary biomarker levels. Patients with higher stages of AKI had higher levels of both biomarkers than those at lower stages. Conclusions: NGAL and IL-18 obviated the disadvantages of creatinine. They were efficient in early detection of AKI, in differentiating pre-renal from intrinsic AKI and in predicting the severity of AKI reliably in post-cardiac surgery patients.

Cataract surgery in chronic Stevens–Johnson syndrome: aspects and outcomes

Aim To assess the outcome of cataract surgery in patients with chronic sequelae of Stevens–Johnson syndrome (SJS). Methods Setting: Tertiary eye care centre in South India. Design: Retrospective, non-comparative, consecutive, interventional case series. Study period: March 2003 to May 2014. Of the 1662 consecutive patients with SJS, 32 patients (40 eyes) with chronic sequelae of SJS who underwent cataract surgery were included. The main outcome measures were best-corrected visual acuity (BCVA) and ocular surface stabilisation. The visual acuity was expressed with reference to the logMAR. Results The study included 12 men (37.5%) and 20 women (62.5%). 8 patients (25%) had bilateral cataract surgeries. The median preoperative BCVA was 1.61 (IQR, 0.80 to 2.78) (only perception of light in three eyes). The median BCVA in the immediate postoperative period was 0.60 (IQR, 0.30 to 1.48) (perception of light in an eye) which was significantly different from the preoperative BCVA (p<0.0001). The median BCVA achieved was 0.30 (IQR, 0.00 to 0.80), suggesting further improvement. Median time taken to achieve this postoperatively was 1.5 months (IQR, 8 days to 3 months). The median BCVA during the last follow-up was 0.48 (IQR, 0.18 to 1.00). The preferred type of cataract surgery was phacoemulsification. Ocular surface condition remained stable in 35 eyes (87.5%). Ocular surface breakdown in four eyes (10%) was managed appropriately. Conclusion Cataract surgery outcome can be visually rewarding in chronic sequelae of SJS provided ocular surface integrity is adequately maintained preoperatively and postoperatively.