Identifying the origin of single corneal cells by DNA fingerprinting - Part I - Implications for corneal limbal allografting

Purpose. To demonstrate that the combination of impression cytology and single cell DNA fingerprinting represents a powerful tool that is suitable for detecting transplanted cells after corneal limbal allografting. Methods, Fifty single cells were obtained by corneal impression cytology from 12 patients undergoing cataract surgery. Individual cells were isolated from samples by micromanipulation. Polymerase chain reaction and short tandem repeat profiling was used to obtain forensic standard DNA fingerprints from single cells. Blood samples taken at the time of impression cytology provided control fingerprints. Results, informative DNA fingerprints were obtained from all corneal samples and 66% (33 of 50 cells) of isolated single cells, Of all fingerprints obtained, most (91%, 30 of 33 fingerprints) corneal fingerprints matched corresponding blond sample fingerprints. At least one corneal fingerprint matched the corresponding blood sample fingerprint in 83% (10 of 12 patients) of the patients in the study, Conclusions. This extremely specific single cell DNA fingerprinting system permits accurate identification of individual corneal epithelial cells, allowing very reliable determination of their origin, which will enable host and donor cells to be distinguished from each other after keratolimbal allografting procedures. even if the host and donor are the same sex or siblings. These DNA fingerprinting methods allow assessment of quality and quantity of donor cell survival, as well as survival time. The extreme sensitivity and accuracy of the technique means that should contamination occur, it would be identified, thus ensuring meaningful results.

Detection of purkinje images for automatic positioning of fixation target and interferometric measurements of anterior eye chamber

In cataract surgery, the eye’s natural lens is removed because it has gone opaque and doesn’t allow clear vision any longer. To maintain the eye’s optical power, a new artificial lens must be inserted. Called Intraocular Lens (IOL), it needs to be modelled in order to have the correct refractive power to substitute the natural lens. Calculating the refractive power of this substitution lens requires precise anterior eye chamber measurements. An interferometry equipment, the AC Master from Zeiss Meditec, AG, was in use for half a year to perform these measurements. A Low Coherence Interferometry (LCI) measurement beam is aligned with the eye’s optical axis, for precise measurements of anterior eye chamber distances. The eye follows a fixation target in order to make the visual axis align with the optical axis. Performance problems occurred, however, at this step. Therefore, there was a necessity to develop a new procedure that ensures better alignment between the eye’s visual and optical axes, allowing a more user friendly and versatile procedure, and eventually automatizing the whole process. With this instrument, the alignment between the eye’s optical and visual axes is detected when Purkinje reflections I and III are overlapped, as the eye follows a fixation target. In this project, image analysis is used to detect these Purkinje reflections’ positions, eventually automatically detecting when they overlap. Automatic detection of the third Purkinje reflection of an eye following a fixation target is possible with some restrictions. Each pair of detected third Purkinje reflections is used in automatically calculating an acceptable starting position for the fixation target, required for precise measurements of anterior eye chamber distances.

A biodegradable drug delivery system for the treatment of postoperative inflammation

Cataract surgery is often performed in patients suffering from associated pathologies. Our goal is to develop a biodegradable drug delivery system (DDS) combined with the artificial intraocular lens (IOL). DDS were manufactured using poly(D,L-lactide-co-glycolide), or PLGA, and were loaded with triamcinolone acetonide (TA). The loading capacity was approximately 1050 microg of TA per DDS. The higher the molecular weight of PLGA (34,000, 48,000 and 80,000Da), the slower was the release of TA in vitro. Cataract surgery was performed on the right eye of rabbits. IOL was inserted with (i) no DDS, (ii) unloaded DDS PLGA48000, (iii) one loaded DDS PLGA48000, (iv) two loaded DDS. The number of inflammatory cells and the protein concentration were measured in the aqueous humor (AH). Unloaded DDS showed good ocular biocompatibility. One DDS PLGA48000 loaded with TA significantly reduced postoperative ocular inflammation. Two loaded DDS PLGA48000 was even more effective in inhibiting such inflammation. On long-term observation (days 63 and 84), reduction of inflammation could be obtained by insertion of one DDS PLGA48000 and a second DDS PLGA80000. Therefore, our "all in one" system is very promising since it could replace oral treatment and reduce the number of intraocular injections

Traitement du décollement de rétine du pseudophaque: étude rétrospective comparant la vitrectomie sans indentation au traitement ab-externo [Vitrectomy without scleral buckle versus ab-externo approach for pseudophakic retinal detachment: comparative retrospective study].

PURPOSE: Retinal detachment (RD) is a major complication of cataract surgery, which can be treated by either primary vitrectomy without indentation or the scleral buckling procedure. The aim of this study is to compare the results of these two techniques for the treatment of pseudophakic RD. PATIENTS AND METHODS: The charts of 40 patients (40 eyes) treated with scleral buckling for a primary pseudophakic RD were retrospectively studied and compared to the charts of 32 patients (32 eyes) treated with primary vitrectomy without scleral buckle during the same period by the same surgeons. To obtain comparable samples, patients with giant retinal tears, vitreous hemorrhage, and severe preoperative proliferative vitreoretinopathy (PVR) were not included. Minimal follow-up was 6 months. RESULTS: The primary success rate was 84% in the vitrectomy group and 82.5% in the ab-externo group. Final anatomical success was observed in 100% of cases in the vitrectomy group and in 95% of cases in the ab-externo group. Final visual acuity was 0.5 or better in 44% of cases in the vitrectomy group and 37.5% in the ab-externo group. The duration of the surgery was significantly lower in the ab-externo group, whereas the hospital stay tended to be lower in the vitrectomy group. In the vitrectomy group, postoperative PVR developed in 3 eyes and new or undetected breaks were responsible for failure of the initial procedure in 2 eyes. CONCLUSION: Primary vitrectomy appears to be as effective as scleral buckling procedures for the treatment of pseudophakic RD.

La chirurgie combinée phacoémulsification/pelage de membrane épirétinienne et oedème maculaire [Combined phacoemulsification/membrane resection and macular edema].

PURPOSE: To evaluate the occurrence of macular edema (ME) after epiretinal membrane resection, managed either with simple vitrectomy or with combined vitrectomy and phacoemulsification. MATERIAL AND METHODS: Two groups of 12 patients had a vitrectomy for epiretinal membrane associated or not to a phacoemulsification. A fundus fluorescein angiography was performed pre and postoperatively and at least 3 months after the surgery. RESULTS: In the group of patients who had a simple vitrectomy, a ME was observed in 50% of the cases preoperatively and in 25% of the cases at the end of follow-up. In 3 cases, preoperative ME was worsened after the surgery. In the group of patients who were treated by a combined vitrectomy and phacoemulsification, a ME was observed in 25% of the cases preoperatively and in 50% of the cases at the end of follow-up. A de novo ME was observed in 3 cases. CONCLUSION: Combined vitrectomy and cataract surgery could allow a rapid recovery of visual acuity but might increase the occurrence of ME.

Acquired oscillopsia: potential complication after multifocal IOL implantation

A healthy 60-year-old woman had uneventful bilateral sequential cataract surgery with diffractive multifocal intraocular lens (IOL) implantation. Immediately after surgery in the first eye, the patient complained of right monocular oscillopsia during motion. Surgery in the second eye was followed by the same symptoms. Ocular motility was normal. Any movement of head or eye was accompanied by oscillopsia, disappearing immediately upon cessation of movement. Slitlamp examination revealed pseudophacodonesis, without obvious zonular laxity. We postulate that the rapid oscillation of an unsteady multifocal IOL during head or eye movement caused the optical steps to pass in front of the visual axis. Cataract surgeons must be aware of this potential, but rare, complication before deciding to implant a multifocal IOL.

Intraocular penetration of penciclovir after oral administration of famciclovir: a population pharmacokinetic model.

OBJECTIVES: We developed a population model that describes the ocular penetration and pharmacokinetics of penciclovir in human aqueous humour and plasma after oral administration of famciclovir. METHODS: Fifty-three patients undergoing cataract surgery received a single oral dose of 500 mg of famciclovir prior to surgery. Concentrations of penciclovir in both plasma and aqueous humour were measured by HPLC with fluorescence detection. Concentrations in plasma and aqueous humour were fitted using a two-compartment model (NONMEM software). Inter-individual and intra-individual variabilities were quantified and the influence of demographics and physiopathological and environmental variables on penciclovir pharmacokinetics was explored. RESULTS: Drug concentrations were fitted using a two-compartment, open model with first-order transfer rates between plasma and aqueous humour compartments. Among tested covariates, creatinine clearance, co-intake of angiotensin-converting enzyme inhibitors and body weight significantly influenced penciclovir pharmacokinetics. Plasma clearance was 22.8 ± 9.1 L/h and clearance from the aqueous humour was 8.2 × 10(-5) L/h. AUCs were 25.4 ± 10.2 and 6.6 ± 1.8 μg · h/mL in plasma and aqueous humour, respectively, yielding a penetration ratio of 0.28 ± 0.06. Simulated concentrations in the aqueous humour after administration of 500 mg of famciclovir three times daily were in the range of values required for 50% growth inhibition of non-resistant strains of the herpes zoster virus family. CONCLUSIONS: Plasma and aqueous penciclovir concentrations showed significant variability that could only be partially explained by renal function, body weight and comedication. Concentrations in the aqueous humour were much lower than in plasma, suggesting that factors in the blood-aqueous humour barrier might prevent its ocular penetration or that redistribution occurs in other ocular compartments.

Nouveautés en médecine interne générale ambulatoire (2) [General internal medicine: review of year 2009 from the ambulatory perspective (2)]

Despite two international studies, there is still no consensus concerning prostate cancer screening. The results of a meta-analysis are making us question our convictions concerning pneumococcal vaccination. The preoperative work-up of cataract surgery can be simplified. When describing the efficacy of a treatment to a patient, relative risks are better understood than absolute risks. For rotator cuff syndrome, intramuscular corticosteroid injections are as efficient as intra-articular injections. In patients prescribed clopidogrel, a proton pump inhibitor is not absolutely necessary. The arrival of a anticoagulant that does not need blood monitoring is an interesting option in atrial fibrillation.

Retinal embolisation with localised retinal detachment following retrobulbar anaesthesia.

BACKGROUND: The aim of this communication is to describe an unusual and serious complication of retrobulbar anaesthesia for cataract surgery. HISTORY AND SIGNS: A 78-year-old female was referred for visual loss (light perception) 24 hours after apparently uneventful cataract surgery with retrobulbar anaesthesia in her left eye. Fundus examination revealed multiple arterial emboli and a localised retinal detachment. MRI revealed a retrobulbar hypersignal of the optic nerve associated with perineuritis. The cardiovascular examination was normal. We assumed this condition resulted from injection of the anaesthetic mixture into the optic nerve. THERAPY AND OUTCOME: In order to improve retinal circulation and oxygenation, the intraocular pressure was maximally lowered and anticalcic therapy administered, expecting optimal arterial dilatation. Methylprednisolone (1 g/day 3 days i. v., then rapidly tapered) was also added. The retina slowly reattached but visual acuity remained unchanged. CONCLUSIONS: Retrobulbar anaesthesia is routinely used for ocular surgery. Serious complications may still happen, however. This case adds to the previously reported spectrum of complications from retrobulbar anaesthesia.

Inflammation d'une pinguécula ectopique [Inflammation of an ectopic pinguecula].

An 80-year-old male patient experienced recently diagnosed swelling of the limbal conjunctiva. In his clinical history were found cataract surgery on the right eye 3 months before, chronic open angle glaucoma effectively treated by local eye drops, treated systemic hypertension and hypercholesterolemia. On ophthalmic examination, a conjunctival mass was present in the inferior lateral conjunctival quadrant next to the limbus, with numerous vessels visible at its top. Treatment with topical corticosteroids failed to obtain regression, but decreased the local inflammatory signs. The persistence of the mass led to its surgical excision under local anesthesia. Histopathology found a subepithelial accumulation of modified collagen bundles typical of elastotic degeneration. Capillary vessels were seen in the superficial subepithelial area, attesting to the high degree of vascularization observed clinically. The final diagnosis was a pinguecula, which was not exactly located on the horizontal meridian area as it is usual.

Predictive Factors for Intraocular Pressure Reduction after Phacoemulsification in Swiss Patients.

Background: Phacoemulsification is known to induce postoperative intraocular pressure (IOP) reduction, the degree of which varies according to glaucoma subtype and race. The authors set out to investigate the effect of cataract surgery on IOP, in a Swiss Caucasian population, and identify ocular predictive factors. Patients and Methods: 234 consecutive cases of 188 patients undergoing phacoemulsification between January 2011 and December 2012 were retrospectively reviewed and data collected. Exclusion criteria included acute angle closure, malignant glaucoma and pre-existing or subsequent glaucoma surgery. Pre- and post-operative visual acuity, IOP, gonioscopic findings, glaucoma medications, and laser treatments were recorded for eligible eyes. All eyes received the same postoperative regimen. Using multivariate analysis the predictive power of preoperative IOP, iridocorneal angle width, axial length on IOP reduction following phacoemulsification at months 3, 6 and 12 postoperatively were assessed. Eyes with narrow angles were compared against those with open angles. Results: 172 eyes of 121 patients met the inclusion criteria; mean age was 70.3 years (SD ± 10.7 years), with 77 males. Preoperatively median IOP was 16 mmHg (range 9-32 mmHg), mean number of glaucoma medications was 1.2 (SD ± 1.1), median visual acuity was 0.28 LogMAR (range 0-2.3LogMar). At 3 months post-operatively mean IOP decreased to 14 mmHg (p < 0.01) and remained statistically significantly reduced until 12 months, mean number of glaucoma medications was reduced to 1.0 and mean Snellen visual acuity increased to 0.8. Multivariate analysis revealed that pre-operative IOP and iridocorneal angle width (at 3 months) were significant predictive indicators of IOP reduction. At 12 months, IOP reduction was similar between open and narrow angle groups and total IOP reduction was no longer statistically significant. No intraoperative complications were recorded. Conclusions: Intraocular pressure reduction following phacoemulsification was greatest during the very early post-operative period, particularly in narrow angle patients. By one year, angle size was no longer predictive of IOP lowering, however pre-operative IOP and number of anti-glaucoma medications remained correlated with total IOP reduction.

Correlación entre el resultado refractivo post-catarata con la predicción biométrica pre-operatoria

La cirugía de cataratas por Facoemulsificación es tal vez uno de los procedimientos más realizados en la práctica de oftalmología general, sin embargo el resultado refractivo de esta cirugía no siempre llena las expectativas del oftalmólogo y del paciente, es por esto que es de gran importancia observar los resultados post quirúrgicos obtenidos y las distintas variables que pudieron influir en dicho resultado. Objetivo: determinar la capacidad predictiva de la formula biométrica empleada en el preoperatorio con el resultado refractivo post operatorio expresada en porcentajes. Materiales y métodos: se realizó un estudio de correlación basándose en la refracción prevista por la biometría y la refracción encontrada en el post operatorio. Se analizó los diferentes grupos de pacientes miopes, hipermétropes y emétropes en de los rangos de 0,50D, 0,75 D y 1,00D. Resultados: el porcentaje de pacientes que presento 0,50D de diferencia con el previsto fue de 57,7% para el total, 100% para hipermétropes, 53,1% para emétropes, 56,3% para miopes. En el rango de 0,75D 71,2% para el total, 62,5% para emétropes y 81,3% para miopes. En el rango de 1,00D 82,7% para el total, 75% para emétropes y 93,8% para miopes. Conclusiones: la formula SRK/T presento un buen desempeño en todos los grupos encontrándose resultados concordantes con los descritos en la literatura.

El efecto de los anti inflamatorios no esteroideos sobre el espesor retiniano, inflamación y agudeza visual posterior a la extracción de catarata: un estudio prospectivo comparando nepafenac y dexametasona

Objetivos: Comparar el volumen macular total (VMT) y espesor retiniano, la agudeza visual mejor corregida (AVCC) y la incidencia de edema macular post cirugía de catarata, en ojos tratados con nepafenac 0.1%, dexametasona 0.1% o la combinación de los dos. Métodos: En una estudio prospectivo, aleatorizado, controlado y ciego para el observador, se aleatorizaron 147 ojos con catarata para recibir dexametasona 0.1% cada 6 horas por 12 días de forma postoperatoria, nepafenac 0.1% cada 8 horas antes de cirugía y por 15 días postoperatorios o la combinación de los dos. Los desenlaces medidos fueron presión intraocular a la primera y sexta semana, AVCC, VMT (medido por OCT), espesor foveal y perifoveal, y la presencia o ausencia de edema macular (espesor foveal > 240 micras, medido por OCT) a las 6 semanas. Resultados: En la primera semana, la presión intraocular fue significativamente mayor en el Grupo de dexametasona (p<0.05), y luego fue similar entre grupos a la sexta semana. No se presentaron diferencias significativas en agudeza visual. El espesor perifoveal fue significativamente menor en el grupo de nepafenac (p<0.05). La incidencia de edema macular medido por OCT fue de 7.5% (11 ojos); de estos 5 pertenecían al grupo dexametasona, tres al Grupo de Nepafenac y 3 ojos al Grupo de la combinación (p>0.05) Conclusión:. Los resultados demuestran que el nepafenac es por lo menos igual de efectivo para evitar la inflamación postoperatoria al compararlo con dexametasona, y adicionalmente podría ser útil para evitar el edema macular post cirugía de catarata.

Factores asociados a recuperación visual deficiente después de cirugía exitosa para desprendimiento de retina regmatógeno

Introducción: Varias características pueden afectar el pronóstico visual después de resolver quirúrgicamente el desprendimiento de retina. Existen características no observables por el ojo humano por si solo pero si por tomografía óptica coherente que se relacionan con la recuperación visual. Objetivo: Describir las características clínicas y topográfica en los periodos pre y postquirúrgico de ojos que ha sufrido DR regmatógeno con compromiso macular y su relación con la calidad de recuperación visual después de una cirugía considerada exitosa desde el punto de vista anatómico. Materiales y métodos: Estudio descriptivo en el que se comparan algunas características en tres periodos perioeperatorios, uno antes y dos después de cirugía (3 y 6 meses) de 24 ojos con DRregmatógeno y compromiso macular intervenidos mediante retinopexia combinada con vitrectomía pars plana. Resultados: La recuperación visual mejor o igual que logMAR 0,397 (20/50) se dió en 41,7% de ojos y 16,7%. alcanzaron agudeza visual logMAR 0,301 (20/40). Cinco ojos no alcanzaron una ganancia de líneas de visión mayor a cinco. El líquido submacular ausente se observó en la mayoría de ojos que recuperaron más de cinco líneas al igual que aquellos con elipsoide conservado. La regularidad del neuroepitelio y el edema en el periodo posquirúrgico no mostraron comportamientos claros respecto a recuperación visual al igual que la altura del desprendimiento y el número de cuadrantes afectados. Una mejor recuperación visual fue más frecuente en aquellos con menos de cinco semanas de desprendimiento de retina. Conclusiones: El retraso menor a cinco semanas en la resolución del desprendimiento de retina, la conservación del elipsoide y la ausencia de líquido submacular en el periodo postquirúrgico se observó más frecuentemente en ojos con mejor recuperación visual.

Cambios maculares y de capa de fibras nerviosas ganglionares posterior a la vitrectomía pars plana y sus factores pronósticos en la fundación oftalmológica nacional

OBJETIVOS: Determinar los factores pronóstico, cambios maculares morfológicos y de capa de fibras nerviosas ganglionares posterior a vitrectomía pars plana, en la Fundación Oftalmológica Nacional. MATERIALES Y MÉTODOS: Estudio longitudinal de antes y después (3y6 meses) de la vitrectomía pars plana (VPP) en pacientes con membrana epirretiniana, agujero macular, síndrome de tracción vítreo macular y opacidades vítreas no-inflamatorias. Se realizó seguimiento clínico y con tomografía de coherencia óptica. RESULTADOS: Grupo de 60 pacientes (mujeres 65.0%), edad promedio 65.45+9.49años y tiempo de enfermedad promedio 23+29.79meses. Las indicaciones de VPP (n=60ojos) fueron agujero macular (38.3%) y membrana epirretiniana (36.7%). Se encontró diferencia significativa entre grosor del complejo capa de células ganglionares (CCG)+capa plexiforme interna (CPI) inicial y 3 meses (p=0.039), correlación entre grosor del complejo CCG+CPI al tercer y sexto mes (r=0.704,p<0.001) y grosor del complejo CCG+CPI al tercer mes con grosor foveal central (CFT) al tercer y sexto mes (r=–0.594,p<0.001 y r=–0.595,p=0.001). Mayores de 65años tenían menor grosor de CFNG a 6meses (r=-0.528,p=0.007). El grosor de CFNG promedio y la presencia de la zona elipsoide inicial fueron factores pronósticos de buena agudeza visual al tercer mes de VPP (r2=0.414,p=0.018, y r2=0.414,p=0.010). CONCLUSIÓN: El grosor de CFNG y la presencia de la zona elipsoide inicial tienen alta capacidad predictiva de buena agudeza visual al tercer mes de VPP, y, correlación inversa entre grosor del complejo CCG+CPI con CFT al tercer y sexto mes de VPP.