How genetics works: An illustrative case report.

In this communication, we report the case of a four year old boy who presented with reduced vision in the right eye. He had visual acuity of light perception right eye and 6/12 in the left eye and anterior segment examination was normal. Fundus examination of the right eye showed a falciform retinal fold extending from the optic nerve temporally involving the entire retina with exudates within the falciform fold and dense pigmentation peripherally. The left eye showed mild macular temporal dragging of the vessels and 360° of peripheral laser scars. In addition he also had some characteristic systemic features such as developmental delay, obesity, dysmorphic facies and tapered fingers. Using this case as an example, we present a systematic, logical approach to a patient with a possible genetic disorder. The growing field of ocular genetics now allows for improved diagnosis using stepwise cost efficient testing as demonstrated herein.

Dynamics of tear fluid desiccation on a glass surface: a contribution to tear quality assessment

BACKGROUND: Fern-like crystalloids form when a microvolume of tear is allowed to dry out at ambient conditions on a glass surface. Presence of crystalloids in tear "microdesiccates" is used to evaluate patients with Dry-Eye disease. This study aims to examine morphologically the desiccation process of normal tear fluid and to identify changes associated with accelerated tear evaporation. Tear microdesiccates from healthy (Non-Dry Eye) and Dry Eye subjects were produced at ambient conditions. Microdesiccate formation was monitored continuously by dark-field video microscopy. Additionally, accelerated desiccation of tear samples from healthy subjects was conducted under controlled experimental conditions. Particular morphological domains of tear microdesiccates and their progressive appearance during desiccation were compared. RESULTS: In normal tear microdesiccates, four distinctive morphological domains (zones I, II, III and transition band) were recognized. Stepwise formation of those domains is now described. Experimentally accelerated desiccation resulted in marked changes in some of those zones, particularly involving either disappearance or size reduction of fern-like crystalloids of zones II and III. Tear microdesiccates from Dry Eye subjects may also display those differences and be the expression of a more synchronous formation of microdesiccate domains. CONCLUSION: Morphological characteristics of tear microdesiccates can provide insights into the relative rate of tear evaporation.

Historia natural de retinopatía diabética en un estudio a largo plazo en pacientes con diabetes tipo 1. Factores de riesgo para progresión a enfermedad proliferante / Natural history of diabetic retinopathy in a retrospective cohort of type 1 diabetics

Background: Diabetic retinopathy is one of the most common causes of blindness among adults. Aim: To report the natural history of diabetic retinopathy among Chilean patients with type 1 diabetes followed for a mean of 18 years. Material and methods: Retrospective review of medical records of 39 patients aged 26 to 70 years, (20 females, 78 eyes) with type 1 diabetes controlled by the same ophthalmologist from 1971 to 2008. A questionnaire was sent to each patient and their treating physician to request information about the evolution of the disease and metabolic control. Results: The questionnaire was answered by 24 patients (62 percent) and 21 attending physicians (54 percent). Small hard drusen were observed in 25 patients (64 percent). In 12 cases the drusen were detected before the development of any type of retinopathy. Eleven women became pregnant and retinopathy progressed in four of them. Twently three patients (59 percent) developed proliferative diabetic retinopathy (PDR). Patients with PDR had a significantly longer duration of diabetes and worse glycemic control. There was a higher frequency of diabetic nephropathy in the PDR group, but only 13 patients out of 23 with PDR had nephropathy. The retinopathy progressed to high risk PDR two years after successful kidney-pancreas transplantation in one patient. Conclusions. In patients with type 1 diabetes mellitus, small hard drusen may be the initial manifestation of diabetic retinopathy. Risk factors for progression to PDR were duration of diabetic and poor glycemic control. Nephropathy was more prevalent in patients with PDR, but a significant group of PDR patients did not have demonstrable nephropathy (RevMéd Chile 2009; 137:1145-52).

Encefalomielitis diseminada aguda en pediatría / Acute disseminated encephalomyelitis in children

La encefalomielitis diseminada aguda es una patología poco frecuente, pero de gran impacto en salud pública. Se sospecha clínicamente y diagnóstica en base a los hallazgos de estudios imagenológicos, como resonancia nuclear magnética. En este artículo se realiza una revisión de la literatura para orientar al pediatra en caso de sospecha del diagnóstico.