Solar UV Radiation in the Tropics: Human Exposure at Reunion Island (21° S, 55° E) during Summer Outdoor Activities.

Reunion Island is a popular tourist destination with sandy beaches, an active volcano (Piton de la Fournaise), and Piton des Neiges, the highest and most dominant geological feature on the island. Reunion is known to have high levels of solar ultraviolet radiation (UVR) with an ultraviolet index (UVI) which can reach 8 in winter and 16 in summer (climatological conditions). UVR has been linked to skin cancer, melanoma, and eye disease such as cataracts. The World Health Organization (WHO) devised the UVI as a tool for expressing UVR intensity. Thresholds ranging from low (UVI 1-2) to extreme (UVI > 11) were defined depending on the risk to human health. The purpose of the study was to assess UVR exposure levels over three of the busiest tourist sites on the island. UVR was measured over several hours along popular hiking trails around Piton de la Fournaise (PDF), Piton des Neiges (PDN), and St-Leu Beach (LEU). The results were compared with those recorded by the local UV station at Saint-Denis. In addition, cumulative standard erythemal dose (SED) was calculated. Results showed that UVI exposure at PDF, PDN, and LEU were extreme (>11) and reached maximum UVI levels of 21.1, 22.5, and 14.5, respectively. Cumulative SEDs were multiple times higher than the thresholds established by the Fitzpatrick skin phototype classification. UVI measurements at the three study sites showed that Reunion Island is exposed to extreme UVR conditions. Public awareness campaigns are needed to inform the population of the health risks related to UVR exposure.

Prevalence of suspected glaucoma in Haiti: a pilot study.

OBJECTIVE: Gather epidemiological data pertaining to the prevalence of suspected glaucoma in rural and urban areas of Haiti. DESIGN: Cross-sectional pilot study. PARTICIPANTS: Haitians of African ancestry. METHODS: We conducted a cross-sectional study on 211 Haitians of African ancestry (76 males and 135 females) aged 40 years and over. The mean age was 54.6 ± 10.9 years. The data were collected in glaucoma screening clinics at health fairs held in urban Port-au-Prince (57 people) and three rural regions (154 people) during a two-week medical mission to Haiti in November 2014. An ophthalmic exam with intraocular pressure measurement (with Tonopen) and dilated fundus exam were conducted. RESULTS: The average C/D was 0.41 ± 0.18. The prevalence of suspected glaucoma, defined as C/D ≥ 0.7, asymmetry of ≥0.2 or significant rim notching, was 14.2%. The average IOP was 18.4 ± 5.4. Ocular hypertension (IOP ≥ 24mmHg) was found in 19.0% of participants. CONCLUSIONS: The prevalence of ocular hypertension and glaucoma based on suspect optic nerves in our sample population was high, indicating a strong need for access to ophthalmologic care in the Haitian population.

The effects of the age of onset of strabismus on monocular and binocular visual function in genetically identical twins.

OBJECTIVE: Both genetic and environmental factors are thought to play a role in the pathogenesis of strabismus and subsequent ocular dominance and amblyopia. Our purpose was to compare the characteristics of sensory visual function in 2 adult monozygotic (genetically identical) twins who presented with esotropia at different ages. METHODS: Monocular and binocular visual function was measured in the twins. Contrast sensitivity was used to assess monocular function. Suppressive and stereoscopic measurements were undertaken to assess binocular function. All tests were run using a 2-alternative forced choice psychophysical procedure. Eighteen short tandem repeats (STR) were genotyped across the genome in both twins to determine their exact relationship. RESULTS: Twin 1 (nondominant eye OD) was diagnosed with esotropia at 6 months of age, whereas twin 2 (nondominant eye OS) was diagnosed with esotropia at 5 years of age. They underwent a similar corrective surgical intervention soon after diagnosis to correct their esodeviations. Monocular contrast sensitivity was poorer for twin 1, particularly at intermediate spatial frequencies. In addition, twin 1 demonstrated complete suppression and unmeasurable stereoscopic function (>300 seconds). On the other hand, twin 2 demonstrated fusion, exhibited only mild suppression, and had near-normal (28 seconds) stereoscopic function. All STR alleles were identical in the twins, proving monozygosity. CONCLUSIONS: Sensory measurements of monocular and binocular visual function in these genetically proven monozygotic twins were significantly different, with the earlier onset of esotropia associated with reduced visual function. Twin 2, whose esotropia was diagnosed at the age of 5 years, had near-normal visual function, both monocularly and binocularly. To the best of our knowledge, this represents the first study of a genetically identical sibling pair with strabismus. By eliminating the genetic differences between these patients, we are able to make powerful observations about the effect of environment on visual function in strabismus.

Prospective case-control trial evaluating silicone gel for the treatment of direct brow lift scars.

OBJECTIVE: To evaluate the effectiveness of a topical silicone gel on scars in patients who had undergone bilateral direct brow lift surgery. DESIGN: A randomized double-blind clinical trial with a placebo applied to one scar and topical silicone gel (Dermatix Ultra; Valeant Pharmaceuticals, Laval, Que.) used on the other scar for 2 months. PARTICIPANTS: Twelve patients (for a total of 24 surgical scars evaluated) were included in the study. METHODS: This study was performed in 2 academic hospitals of the University of Montreal in Montreal, Que. (Maisonneuve-Rosemont Hospital and Notre-Dame Hospital). Inclusion criteria were all bilateral direct brow lift surgeries performed in our hospitals. Exclusion criteria included revision surgery, silicone or latex allergy, and wound infection. Each patient received 2 tubes (1 with silicone gel and 1 with placebo) and applied 1 tube to their right brow scar and the other tube to their left brow scar, following the preassigned instructions. The patient and surgeon were blinded to the nature of the substance that was applied to each scar. At each visit, pictures of both scars were taken, and a questionnaire titled "The Patient and Observer Scar Assessment Scale" was filled out by the patient and the surgeon. A grade ranging from 0 to 10 was given on the multiple criteria in the questionnaire, and the sum of these grades was subsequently used for the data analysis. A lower sum was interpreted as improved scarring. At the end of the study, an independent evaluator graded both scars based on pictures. Follow-up visits were held on day 7, week 6, month 3, and month 6 after surgery. A comparison of the experimental and placebo group was performed with nonparametric tests of Wilcoxon signed rank. RESULTS: A total of 24 scars of 12 patients were analyzed (based on 4 follow-up visits). General improvement of scars was reported by the patient, the surgeon, and based on pictures. No statistically significant difference was found between the group treated with silicone gel and the group treated with placebo. All tests had a p value ≥0.08. CONCLUSIONS: We did not find a statistically significant difference between scars treated with silicone gel and scars treated with the placebo after direct brow lift surgery.

Controversies of the lacrimal system.

Numerous long-standing controversies influence the management of lacrimal sac abscesses, canalicular lacerations, and obstruction of the nasolacrimal duct. We examined the debatable beliefs that underline these controversies and concluded the following: drainage of a pointing lacrimal sac abscess can be well tolerated under local anesthesia, is associated with few adverse events, and should be performed regardless of whether systemic antibiotics have been administered. Reconstruction of monocanalicular lacerations should be considered in all cases, without distinction to whether the injury involves the upper or lower canaliculus. Finally, no firm evidence currently exists supporting intubation with routine dacryocystorhinostomy.