VOLUME 77 - ISSUE 5

The practical advantages of quantifying an angle by a ratio of linear lengths instead of arcs of circles has led to the definition of the prism-diopter, a conventional unity for numbering prisms and measuring strabismic deviations. However, a major inconvenience of using prism-diopter unities to express angular measurements is the non-linearity of the scale, which reaches an infinite value for the angle of 90º, then becomes negative, with decreasing magnitudes for increasing angles between 90º and 180º. As a consequence, arithmetical operations and comparisons of angles measured by such unities present errors of very great magnitudes. In order to retain the advantages of defining an angle by straight line dimensions but to diminish the severe inconveniences of this method, a new definition of the prism-diopter is proposed. Here, instead of defining the prism-diopter by the asymmetrical condition, the conception of this new unity is based on a geometrically symmetrical condition; that of the relationship of an isosceles triangle (where the leg is perpendicular to the bisector of the angle and the bisector itself ). The condition of symmetry for the definition of the new unity represents a conceptual advance because it reproduces the already well accepted, conventional criteria for quantifying the value of a prism, that of its minimum deviation. Furthermore, it corresponds to the most commonly observed clinical conditions of binocular balance. The absolute differences between the unitary values of the prism-diopter and that of the new unity are negligible (0.0025%), but the scale of values expressed by the new unity is closer to the ideal scale of angular measurements. (With the new unity, the infinite value is only reached for an angle of 180º and the errors due to arithmetical operations are much smaller.) Numerical examples showing the advantages of using the new unity of angular measurements instead of the prism-diopter are presented. A mathematical generalization of the modifying concept (partition of an angle) with which the new unity is based is also provided.

Keywords: Strabismus; Visual cortex; Convergence, ocular; Measures

Purpose: To compare the subfoveal choroidal thickness (SFCT) of patients with different severities of obstructive sleep apnea/hypopnea syndrome (OSAHS) and normal controls via enhanced depth imaging optical coherence tomography (EDI-OCT). Methods: In this retrospective, case-control study, 49 eyes from 49 patients that had undergone polysomnography were included. SFCT of the horizontal and vertical line scans were manually measured for all eyes based on EDI-OCT images. Two separate analyses were performed according to different apnea/hypopnea index (AHI) groupings. Initial testing was conducted using non-OSAHS, mild OSAHS (5≤AHI<15), moderate OSAHS (15≤AHI<30), and severe OSAHS (AHI≥30) patient groupings, while secondary testing used non-OSAHS, mild OSAHS (5≤AHI<15), and moderate/severe OSAHS (AHI≥15) patient groupings. Results: The mean SFCT was 314.5 μm in the non-OSAHS patients (n=14), 324.5 μm in the mild OSAHS patients (n=15), 269.3 μm in the moderate OSAHS patients (n=11), and 264.3 μm in the severe OSAHS patients (n=9). SFCT between the four groups revealed no significant differences despite a trend towards slight thinning in the severe group (P=0.08). When the moderate and severe groups were merged and compared with the mild OASHS and non-OSAHS groups, SFCT of the moderate/severe group was found to be significantly thinner than that of the mild group (P=0.016). A negative significant correlation was found between SFCT and AHI in OSAHS patients (r=0.368, P=0.033). Conclusions: In patients with moderate/severe OSAHS, EDI-OCT revealed a thinned SFCT. Other accompanying systemic or ocular diseases may induce perfusion and oxygenation deficiency in eyes of OSAHS patients. Further studies are required in order to determine the exact relationships between ocular pathologies and clinical grades of OSAHS.

Keywords: Sleep apnea syndromes; Tomography, optical coherence; Choroid/pathology; Tonometry, ocular; Polysomnography

Objective: To determine and compare the mast cell count in primary and recurrent vascularized pterygium, and in normal bulbar conjunctiva. Methods: The study included 22 patients with primary pterygium (PP group) and 28 patients with vascularized recurrent pterygium (VRP group) that underwent excision via the limbal conjunctival autograft technique. Normal conjunctiva samples were collected from the superotemporal bulbar conjunctival region, just temporal to the site from which the autograft conjunctival tissue was harvested. The total number of mast cells in the pterygium (primary and recurrent) and control tissue samples was calculated microscopically using 1% toluidine blue stain under 400× magnification. Results: The mean mast cell count in primary and vascularized recurrent pterygium tissue was 7.45 ± 2.06 mm–2 and 16.11 ± 4.33 mm–2, respectively, and the difference was significant (independent samples t-test, P<0.001). The mean mast cell count in pterygium tissue was significantly higher than that in normal conjunctiva tissue in both groups (Student's t-test, P<0.001). Conclusion: An increase in the number of mast cells might play a role in the pathogenesis of recurrent pterygium. Determination of a mast cell count cut-off value could be of diagnostic significance for recurrent pterygium.

Keywords: Mast cells; Pterygium/diagnostic; Recurrence; Toluidine chloride; Conjunctiva

Purpose: To compare intraocular pressure (IOP) using the simplified daily tensional curve (SDTC) between supine and sitting positions in terms of peak levels and amount of fluctuation in both, glaucomatous and healthy subjects. The secondary endpoint was the comparison of these measures with those derived from the water drinking test (WDT). Methods: Thirty patients with primary open-angle glaucoma (POAG) that were undergoing medical therapy and 30 healthy subjects were enrolled in this study. Each patient underwent a diurnal curve between 8 am and 4 pm. After lying down for 5 minutes, the IOP was measured with the Perkins tonometer. Patients were instructed to sit in the upright position for 5 minutes and the tonometry was repeated. At 4:15 pm, the WDT test was performed. Fluctuation was defined as the difference between the highest and the lowest IOP readings (range). The Student's t test was used to assess differences and a P value <0.05 was considered to be statistically significant. Results: The diurnal curve in the supine position demonstrated higher IOP average values (on average 3-4 mmHg higher) compared to the sitting position (p<0.0001) for both groups. IOP peaks were higher in the supine position; however, the IOP range was essentially the same between the three methods. Treated glaucomatous patients had higher IOP levels in all measurements, but the fluctuation for all tests performed appeared to be similar to that of healthy patients. Conclusion: The data suggested that WDT can be used to estimate the diurnal IOP peak and fluctuation observed in the SDTC of the supine position for treated glaucomatous patients. Further studies can compare the possible correlation between the WDT results and those obtained from nocturnal supine measurements.

Keywords: Glaucoma, open-angle/physiopathology; Intraocular pressure/physiology; Circadian rhythm

Purpose: We reported on the clinical approaches of ophthalmology and otorhinolaryngology departments in the treatment of the orbital complications of sinusitis. We also included an in-depth literature review. Methods: We retrospectively reviewed the medical files of 51 patients from January 2008 to January 2014. The records were evaluated for age, gender, type of orbital complications, symptoms, predisposing factors, imaging studies, medical and surgical management, culture results, and follow-up information. SPSS version 15.0 software (Statistical Analysis, The Statistical Package for Social Sciences Inc, Chicago, IL) was used for the statistical analysis. Results: Fifty-one patients met the criteria, with available medical records, for the study (29 male, 22 female). Thirty-two (62.7%) were diagnosed with preseptal cellulitis and 19 (37.3%) with postseptal cellulitis. After a detailed evaluation, 15 were diagnosed with a subperiosteal abscess (SPA), and 4 were diagnosed with orbital cellulitis. The age and gender was similar for the two groups. Five patients with medial SPA were treated with endoscopic sinus surgery, one patient with inferior SPA was treated with external surgery, and six patients with other localizations were treated with a combination of endoscopic sinus surgery and external surgery. All patients presented with periorbital erythema and edema. The length of hospitalization and duration of symptoms were similar in both groups. Visual acuity was between 1/10 to 10/10 (mean 7/10) and statistically significant for preseptal and postseptal cellulitis groups (p<0.001). All patients received intravenous antibiotics upon the first day of admission. Conclusion: Orbital complications of acute sinusitis required intensive follow-up and a multidisciplinary approach. A contrast-enhanced paranasal sinus computerized tomography (CT) scan can detect the extent of the infection. An initial trial of intravenosus (IV) antibiotics may be appropriate when close monitoring is possible. Surgery may be indicated when there has been no improvement within 48 hours of intravenous treatment, loss of visual acuity (under 8/10), and a non-medial abscess.

Keywords: Sinusitis/complications; Orbital diseases/etiology; Abscess

Purpose: Providing data on the late diagnosis and surgical treatment of patients who underwent surgery for total unilateral congenital cataract. Methods: Systematic retrospective review of the medical record of all patients between 0 and 16 years old with total unilateral congenital cataract who underwent surgery at Fundación Vision between January 2010 and July 2012. Results: Medical records of 37 patients (51 % females) were studied, age was 7.4 (± 4.9) years (average ± SD) and 62% lived on Departamento Central (the most populated region from Paraguay). A total of 97.3% patients underwent late surgical treatment and 86.5% received a late diagnosis. The average time elapsed between the diagnosis and the surgical treatment was one month, and 62.2% of the patients underwent surgery within six months from the diagnosis. Conclusion: This study evidences that most of the patients in our series had a late treatment as a result of a late diagnosis. Based on these results we recommend establishing strategies to improve the early detection and surgical treatment of the newborns.

Keywords: Cataract/congenital; Cataract extraction; Late diagnosis; Visual acuity; Paraguay

Purpose: To assess the sociodemographic profiles, teratogen exposures, and ocular congenital abnormalities in Brazilian patients with Möbius sequence. Method: Forty-four patients were recruited from the Brazilian Möbius Sequence Society. This cross-section comprised 41 patients (age, mean ± standard deviation, 9.0 ± 5.5 years) who fulfilled the inclusion criteria. The parent or caregiver answered a questionnaire regarding sociodemographic data and pregnancy history. Patients underwent ophthalmological assessments. They were subdivided into groups according to misoprostol exposure during pregnancy, and the two groups were compared. Results: Mothers/caregivers reported unplanned pregnancies in 36 (88%) cases. Of these, 19 (53%) used misoprostol during their first trimesters. A stable marital status tended to be more frequent in the unexposed group (P=0.051). Incomplete elementary school education was reported by two (11%) mothers in the exposed group and by three (14%) mothers in the unexposed group (P=0.538). The mothers' gestational exposures to cocaine, marijuana, alcohol, and cigarettes were similar in both groups (P=0.297, P=0.297, P=0.428, and P=0.444, respectively). One (5%) case of Rubella infection during pregnancy was found in the unexposed group. The main malformations in the exposed and unexposed groups were the following: strabismus (72% and 77%, respectively), lack of emotional tearing (47% and 36%, respectively), and lagophthalmos (32% and 41%, respectively). Conclusion: Stable marital statuses tended to be more frequent among mothers that did not take misoprostol during pregnancy. Exposures to other teratogens and the main ocular abnormalities were similar in both groups.

Keywords: Möbius syndrome/physiopathology; Teratogens; Congenital abnormalities/etiology; Misoprostol/adverse effects; Pregnancy complications

Purpose: To evaluate the agreement between the methodologies of impression cytology (IC) and histopathology regarding epithelial lesions clinically diagnosed as pterygium and also regarding the detection of unsuspected and associated ocular surface squamous neoplasia (OSSN). Methods: Thirty-two Brazilian patients were included and IC was performed on all pterygia before excision. Histopathogical examination was considered the gold standard and was performed by two experienced ocular pathologists in which consensus existed regarding pterygia diagnosis. IC accuracy was assessed by sensitivity and specificity with a 95% confidence interval. Results: From the 32 primary lesions studied, histopathological examination confirmed the diagnosis of pterygium without atypical cells in 19 cases (60%) and showed unsuspected and associated OSSN cells in 13 cases (40%). IC demonstrated one false-negative and one false-positive result for atypia. Statistical analysis showed an estimated sensitivity of 92%, specificity of 94%, positive predictive value of 92%, and negative predictive value of 94%. Conclusion: IC demonstrated high agreement with histopathological analysis in the detection of atypical epithelial cells in unsuspected OSSN in Brazilian pterygia patients.

Keywords: Pterygium; Conjunctiva; Cornea; Limbus corneae; Ocular surface; Eye neoplasms; Cytological techniques

Objective: To evaluate the effect of riboflavin-ultraviolet-A-induced cross-linking (CXL) following corneal alkali burns in rabbits. Methods: The right corneas and limbi of ten rabbits were burned using a 1N solution of NaOH and the animals were then divided into two groups: a control group submitted to clinical treatment alone and an experimental group that was treated 1 h after injury with CXL, followed by the same clinical treatment as administered to the controls. Clinical parameters were evaluated post-injury at 1, 7, 15, and 30 days by two independent observers. Following this evaluation, the corneas were excised and examined histologically. Results: There were no statistically significant differences in clinical parameters, such as hyperemia, corneal edema, ciliary injection, limbal ischemia, secretion, corneal neovascularization, symblepharon, or blepharospasm, at any of the time-points evaluated. However, the size of the epithelial defect was significantly smaller in the CXL group (p<0.05) (day 15: p=0.008 and day 30: p=0.008) and the extent of the corneal injury (opacity lesion) was also smaller (day 30: p=0.021). Histopathology showed the presence of collagen bridges linking the collagen fibers in only the CXL group. Conclusions: These results suggest that the use of CXL may improve the prognosis of acute corneal alkali burns.

Keywords: Cross-linking reagents; Riboflavin; Ultraviolet therapy/methods; Cornea/ drug effects; Rabbits; Animal

Purpose: Describe the outcomes of thermal laser photocoagulation in three cases of retinal pigment epithelium detachment associated to age-related macular degeneration. Methods: Three patients with avascular retinal pigment epithelium detachment were treated with green diode laser photocoagulation. Mild macular grid laser application, similar to the treatment of diabetic macular edema was performed after an unsuccessful intravitreal anti-angiogenic treatment. Results: After one year of the laser treatment, two cases reached anatomic resolution, with complete absorption of sub-epithelium serum fluid and improvement of the visual acuity. There was stability of the visual acuity and sub-epithelium fluid reduction, which, however, was partial in the third case. No complications related to the treatment occurred until the conclusion of this study. Conclusions: Macular photocoagulation in grid pattern produced regression of avascular serous pigment epithelium detachment associated with age-related macular degeneration in a short follow-up period. Although long term prospective studies with an increased sample are necessary, it is a method that can be applied in selected patients, with absence of sub-retinal neovascularization or sub-epithelium fibrovascular component.

Keywords: Retinal pigment epithelium; Retinal drusen; Laser; Macular degeneration; Retina

We present the unusual case of a 35 year-old woman with stage IV melanoma and widespread metastases, who was undergoing treatment with interferon alpha-2b and who presented with interferon-associated retinopathy. The patient, who had been taking interferon treatment for three months, complained of a sudden loss of visual acuity in the left eye. An ocular examination revealed multiple cotton wool spots along the retina and macular involvement. Interferon treatment was suspended. Although rare, retinopathy represents a potentially serious adverse effect of interferon treatment. Although normally patients are asymptomatic, complications derived of its use may arise, which can lead to significant visual impairment. We therefore suggest that before initiating treatment with this drug, patients should be informed of its potential ocular risks, and that regular eye examinations are conducted along with the treatment.

Keywords: Interferon alfa/therapeutic use; Interferon alfa/adverse effects; Melanoma/secondary; Retinal diseases/chemically induced; Case reports

Here we report the occurrence of pale yellowish perivascular preretinal dots in 12 patients with ocular syphilis. A case series of these patients was examined between March and October 2012 at the Uveitis Sector of Universidade Federal de São Paulo. After diagnostic confirmation of syphilis, fundus photographs and optical coherence tomography (OCT) were performed to verify the localization of the dots, and patients were treated with IV crystalline penicillin for 14 days. The study comprised 11 men (91.6%), 19 eyes, median presentation age of 38.1 years, and panuveitis as the main clinical manifestation (seven patients, 58.3%), being bilateral in four. Ten patients were taking oral prednisone (83.3%). Serum panels performed by the Venereal Disease Research Laboratory (VDRL) showed positive results in eight patients (66.7%), whereas VDRL cerebrospinal fluid (CSF) tests were negative in seven of nine collected (77.8%). However, serum FTA-Abs was positive in 100% of patients, and eight patients (66.7%) had HIV infection. The best corrected visual acuity (BCVA) presented after treatment improved in 10 eyes (55.6%), did not change in seven eyes (38.9%), and worsened in one eye (5.6%). Although not yet acknowledged in the literature as a typical manifestation of ocular syphilis, these are very common findings in clinical practice. We believe that preretinal dots are due to perivasculitis secondary to treponema infection. It is important recognize them and remember that syphilis can present in several forms, including the one presented in this study.

Keywords: Syphilis; Uveitis; Panuveitis; Uveitis, posterior/diagnosis; Retina; Tomography, optical coherence; Eye infections, Bacterial; Case reports

A 21-year-old Caucasian man presented with a complaint of nyctalopia. Visual acuity in both eyes was 20/20 and anterior segment biomicroscopy results were unremarkable. Fundoscopy revealed peripheral avascular zones, minimal peripheral retinal exudation from the retinal vessels, peripheral retinal telangiectasias and anastomosis in both eyes, and retinal vascular dragging toward the temporal periphery in both eyes. Full field electroretinography showed that rod responses were almost absent and that cone responses were reduced. Macular optical coherence tomography showed normal structure in both eyes. Vascular changes were attributed to a subclinical form of familial exudative vitreoretinopathy. This was an interesting case due to the association of familial exudative vitreoretinopathy with rod-cone dystrophy.

Keywords: Retinal diseases/genetics; Vitreoretinopathy, proliferative; Electroretinography; Retinal rod photoreceptor cells; Humans; Male; Adult; Case reports

Hemorrhagic complications of optic pathway diseases are extremely rare causes of acute visual loss associated with dengue fever. In this paper we report a patient presenting with dengue fever and bilateral acute visual loss caused by chiasmal compression due to Rathke's cleft cyst apoplexy. Considering the importance of early diagnosis and treatment to visual recovery, apoplexy of sellar and suprasellar tumors should be considered in the differential diagnosis of patients with acute visual loss and dengue fever.

Keywords: Visual disorders/etiology; Dengue/complications; Retinal hemorrhage; Pituitary apoplexy; Optic chiasm; Humans; Case reports

The purpose of this review was to analyze and describe simulation methods for practical learning and training of the ophthalmoscopy exam and to organize them into specific topics relative to each principle of operation, while evaluating their preliminary results. A critical review of articles that described and evaluated simulated models for ophthalmoscopy published in the last ten years (2004-2014) was performed. One hundred articles about ophthalmology and simulation were found in national and international periodicals, but only a few discussed the examination of the posterior pole of the eye. For this study, 25 articles were considered; those articles described simulation methods, general concepts, and its actual use in ophthalmoscopy. There were many different simulation methods described, but only few articles proved their efficacy or performed a comparison between models. Review of this topic may give information for the critical analysis of the simulation devices and ideas for the development of new ones.

Keywords: Ophthalmoscopy/methods; Education, medical/methods; Models, educational; Clinical competence