Symptomatic classic convergence insufficiency treated with dot card orthoptic exercise

Although lots of studies have been reported on convergence insufficiency (CI), no specific case of CI among African patients has been reported. We report a case of symptomatic <em>classic</em> convergence insufficiency in a female student who previously had been misdiagnosed and managed for refractive error. This case highlights the need for comprehensive binocular vision assessment, administration of validated symptom questionnaires in cases of suspicious CI, and the use of simple and inexpensive vision therapy procedures to manage CI in optometric centres in developing countries.

A review of the classification of nonstrabismic binocular vision anomalies

There are conflicting and confusing ideas in literature on the different types of accommodative and vergence anomalies as different authors turn to classify them differently. This paper sought to review literature on the different classifications and types of nonstrabismic binocular vision anomalies and harmonize these classifications. Search engines, namely Google scholar, Medline, Cinahl and Francis databases, were used to review literature on the classification of accommodative and vergence dysfunctions using keywords like <em>binocular vision dysfunctions</em>, <em>classification of nonstrabismic binocular vision disorders or anomalies</em>, <em>accommodative disorders/anomalies classification</em> and <em>vergence disorders/anomalies classifications</em>, and included works that described these anomalies. Nonstrabismic binocular vision anomalies are classified as accommodative and vergence anomalies. There are three different major types of accommodative anomalies, namely accommodative insufficiency, accommodative infacility (accommodative inertia), and accommodative excess (accommodative spasm), and seven different types of vergence anomalies (convergence insufficiency, convergence excess, divergence insufficiency, divergence excess, basic esophoria, basic exophoria and fusional vergence dysfunctions), which are functional in origin. Functionally, there is a commonly reported interaction between accommodative and convergence insufficiency referred to as pseudoconvergence insufficiency. Accommodative paralysis (subtype of accommodative insufficiency) and vergence anomalies – <em>i.e.</em>, convergence paralysis, convergence spasm and divergence paralysis – are non-functional in origin with underlying systemic disease etiologies. Systemic convergence insufficiency, associated with subnormal accommodation, is a non-functional interaction between the accommodative and convergence insufficiency. The classification of nonstrabismic binocular vision anomalies is based on the description of the clinical signs and the underlying etiology either functional or non-functional in origin. Proper diagnosis and management involves investigation of the underlying etiology in addition to the battery of binocular vision test procedures.

Effect of lotrafilcon A silicone hydrogel contact lens on intraocular pressure measurement

The present paper aims to assess the effect of lotrafilcon A contact lenses (CL) <em>in situ</em> on intraocular pressure (IOP) measurement performed with three portable tonometers (ICare, Tonopen and Perkins). This cross-sectional study included thirty young healthy subjects. Intraocular pressure measurements without CL were performed first, followed by IOP measurements with CL for twenty minutes. ICare IOP measurements obtained with lotrafilcon A CL overestimated IOP values without CL by 1 mmHg (P&lt;0.001). However, both techniques displayed close level of agreement (95% LoA, -4.17 to +1.63 mmHg). Also, differences between both methods tended not to increase (P=0.9). No significant differences were observed between IOP measurements without and with CL for Perkins (paired-t test, P=0.23) and Tonopen XL (pairedt test, P=0.17). In conclusion, adequate IOP measurements through zero power lotrafilcon A silicone hydrogel CL can be obtained with all three tonometers in healthy eyes, although, in case of ICare, the practitioner must be aware of the 1 mmHg overestimation with CL.

Appraisal of the practice of ocular self-medication in Cape Coast Metropolis, Ghana

The purpose of the present study was to assess the practice of ocular self-medication among people of the Cape Coast Metropolis, Central Region of Ghana. A population-based survey involving 421 respondents ≥18 years old was conducted. A pre-tested interview-based questionnaire was used to collect data on demographics, ocular symptoms for which selfmedication was practiced, medical knowledge and self-care orientation. Households were systematically and randomly selected as study units. Analysis was done using SPSS version 16. Descriptive results were expressed as frequency, percentage, and mean±standard deviation, X2 test was used for associations, and logistic regression was used to test for predictors of the practice of ocular self-medication. Prevalence of ocular self-medication was 23.3% with itchy eye being the main ocular symptom for which self-medication was practiced. Local pharmacies were the main source of drug for ocular self-medication. There was no association between medical knowledge and the practice of ocular self-medication (X2=0.126; P=0.722). Some 25.5% experienced adverse effects. In conclusion, the practice of ocular self-medication was without recourse to adequate concept of the practice of self-care but its negative effect was mitigated by the low self-care orientation of the people.

Wavefront optics and retinal image quality

With the increasing importance of optical aberrations in both vision research and clinical practice, it becomes necessary for vision scientists to have a thorough understanding of the concepts behind wavefront optics. Therefore, in this review, we provide some basic wave optics concepts useful to understand wavefront analysis, and describe the application of Zernike polynomials in the decomposition of aberrations. A general description of the human eye optical structure is given, followed by a more detailed analysis of the optical components of the eye and optical aberrations, and their secondary effect on overall optical quality. We further provide an overview of the current corneal and ocular wavefront sensing methods.

Diagnostic accuracy of keratoconus using anterior segment optical coherence tomography

The aims of the present study are i) to evaluate the diagnostic accuracy of RTVue non-contact, high-resolution spectral domain optical coherence tomography (RTVue OCT) in identifying keratoconic eyes from a group of healthy eyes; and ii) to examine how the severity of disease affects diagnostic accuracy. Corneal thickness measurements were performed using the RTVue OCT on 58 eyes of 29 individuals (10 males, 19 females). Of them, 28 eyes were deemed to be keratoconic, and 30 eyes healthy on the basis of clinical findings. Sensitivity, specificity and receiver operating characteristic (ROC) area was calculated overall and by grouping eyes by severity of disease. On the whole, the ROC area was highest for the parameters minimum thickness and difference between minimum and maximum thickness of cornea (0.98). The ROC area for the parameters difference in superior nasal and inferior temporal thickness and difference in superior and inferior thickness was 0.81 and 0.77, respectively. The ROC area in identifying eyes with keratoconus varied as a function of severity of disease. From our analysis we can conclude that the RTVue OCT provides excellent diagnostic ability in identifying moderate to advanced cases of keratoconus.

Keratoconjunctivitis associated with nevirapine toxicity in HIV pregnant woman

Highly active antiretroviral therapy (HAART) is the treatment of choice for human immunodeficiency virus-acquired immunodeficiency syndrome (HIV-AIDS) patients. Severe side effects of these drugs have been described that produce generalized autoimmune blistering diseases, such as Stevens-Johnson syndrome and toxic epidermal necrosis (TEN). These complications may seriously compromise the patient&rsquo;s life or cause disabling consequences such as blindness. We describe a case of 21-year old female HIV patient with a CD4 count of 126 cells/microliter. Ten days post elective caesarean delivery she restarted HAART with nevirapine and developed TEN after approximately two weeks. Nevirapine was discontinued, but despite this, ocular surface disorder persisted. She presented severe bilateral keratoconjunctivitis that was treated with free tear substitutes, moxifloxacyn, and prednisolone acethate eye drops. At 2-month follow up her visual acuity without correction was 20/160 in the right eye and 20/40 in the left. She had bilateral moderate cicatricial keratoconjunctivitis and a central corneal leukoma in the right eye. Early treatment is important and should consist of preservative-free lubricants, and amniotic membrane transplantation to decrease the frequency of severe sequelae such as keratitis and corneal leukomas that will reduce the quality of life for these patients.

Pre-lens tear film evaluation scale: a tool for analyzing the tear film-lens interaction with respect to the material used

In clinical practice, to avoid or reduce the failure rate among users of contact lenses, it is necessary to obtain a detailed patient case history, information concerning symptoms, and a complete eye examination. In addition, application of an auxiliary photographic reference scale might increase the chances of improving initial success or, for existing contact lens wearers, provide insight into the extent or severity of symptoms. Patient symptoms are often directly related to contact lens failure, which in turn is related to the quality of the pre-corneal tear film as well as the <em>wettability</em> of the contact lens surface. We describe the relationship between the quality of the tear film, with particular attention to pre-contact lens tear film, variability in contact tolerance, and the material of which the contact lens is made.

Visual acuity in children with autism spectrum disorder

Today, controversy still surrounds the acuity visual (VA) in adolescents and adults with autism spectrum disorder (ASD). ASD has been associated with hypersensitivity but recent studies have questioned these results. The aim of this study was to compare VA in children with ASD and typically developing children (TD). The study included 34 children: 12 with ASD [people living with (PW) ASD group: 1 female, 11 males] and 22 TD (PWTD group: 9 females, 13 males). The PWASD group was from the Clinica Mexicana de Autismo (CLIMA) and the PWTD group was from the <em>Aztecas</em> elementary school. VA was measured with Kay picture test cards for children without correction. Right eye VA of the PWASD group ranged from 0.2 to 1.0 (0.88&plusmn;0.23) and left eye VA ranged from 0.2 to 1.0 (0.87&plusmn;0.23). Right eye VA of the PWTD group ranged from 0.3 and 1.0 (0.84&plusmn;0.23) and left eye VA ranged 0.3 and 1.0 (0.78&plusmn;0.22). Non-statistically significant differences were found (t-test, P&gt;0.05). Results support the view that visual acuity is not affected in children with ASD compared with TD children.

Repeatability and comparative study of corneal thickness using the Visante™ OCT, OCT II and Orbscan II™

The first purpose of this study was to measure the repeatability the VisanteTM Optical coherence tomographer (OCT) in a normal sample. The second was to compare corneal thickness measured with the VisanteTM OCT to the Zeiss-Humphrey OCT II (model II, Carl Zeiss Meditec) adapted for anterior segment imaging and to the Orbscan IITM (Bausch and Lomb). Fifteen healthy participants were recruited. At the Day 1 visit, the epithelial and total corneal thickness across the central 10 mm of the horizontal meridian was measured using the OCT II and the VisanteTM OCT. Only total corneal thickness across the central 10 mm of the horizontal meridian was measured using the Orbscan II. These measurements were repeated on Day 2. Mean central corneal and epithelial thickness using the Visante&trade; OCT at the apex of the cornea was 536&plusmn;27 mm and 55&plusmn;2.3 mm. Mean corneal and epithelial thickness using OCT II at the apex was 520&plusmn;25 mm and 56&plusmn;4.9 mm. Mean total corneal thickness measured with the Orbscan II was 609&plusmn;29 mm. The coefficient of repeatability (COR) ranged from &plusmn;7.71 to &plusmn;8.98 mm for total corneal thickness and from &plusmn;8.72 to &plusmn;9.92 mm for epithelial thickness. Correlation coefficients of concordance (CCC&rsquo;s) were high for total corneal thickness for test-retest differences ranging from 0.97 to 0.99, CCCs for epithelial thickness showed moderate concordance for both the instruments. There is good repeatability of corneal and epithelial thickness using each OCT for test-retest differences compared to the between instrument repeatability. Measurements of epithelial thickness were less robust.