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PubMed1992

Head trauma and low vision: clinical modifications for diagnosis and prescription.

Head-trauma patients benefit from many optical and non-optical devices usually associated with low vision care. This article reviews the most common modifications of clinical examination techniques required to facilitate the evaluation of trauma patients who may benefit from or require low vision devices. A discussion of the importance of incorporating common optical and non-optical devices which can enhance the lives of traumatized patients will follow.

Brain Injuries↗
PubMed1992

Optometric management of binocular dysfunctions secondary to head trauma: case reports.

Extropia, esotropia, hyper elements, visual sequencing problems, accommodative dysfunctions and inefficient Motor Planning are common consequences of head trauma. Optometric visual therapy is an effective treatment modality for these dysfunctions. Two case reports are presented in order to illustrate optometric management of patients exhibiting these problems secondary to head trauma.

Adult↗
PubMedDate not supplied

The importance of the phase transfer function to visual function and visual quality metrics.

PURPOSE: To propose a vision quality metric that directly incorporates the phase transfer function. METHODS: The process of retinal image formation from the pupil to the retina is presented to identify possible domains for calculating vision quality metrics. These domains are pupil plane metrics using ocular aberrations, and retinal plane metrics using the point spread function or optical transfer function. The importance of the phase transfer function to visual performance is demonstrated and a method is proposed for directly including phase in a vision quality metric based on ocular wavefront error. RESULTS: A family of vision quality metrics is proposed, which directly incorporates the Stiles-Crawford effect, contrast sensitivity function, and the phase transfer function. CONCLUSION: The phase transfer function is an important aspect of the quality of an image, and it may be directly included in metrics intended to quantify vision quality.

Contrast Sensitivity↗
PubMed2004

[Quantitative assessment of quality of vision].

The importance of quality of vision (QOV) along with quality of life (QOL) in medicine has been recently widely recognized. We have conducted studies to quantitatively analyze factors related to QOV. Irregular astigmatism can be a significant obstacle for achieving satisfactory QOV. Videokeratography data were broken down using Fourier harmonic series analysis into spherical power, regular astigmatism (second harmonic component, n = 2), asymmetry (n = 1), and higher order irregularity (n > or = 3). The irregular astigmatism component calculated by the Fourier analysis significantly correlated with best spectacle-corrected visual acuity. Software was developed to display color-coded maps for the four Fourier indices. The normal range was defined for each Fourier index, and eyes with pathologic and postsurgical conditions were evaluated using the normal range. Progression of keratoconus over time was quantitatively described by Fourier analysis of the videokeratography data. Using the Fourier method, changes in corneal topography following suture removal after penetrating keratoplasty were evaluated. Fourier analysis of videokeratography data significantly facilitated determination of refraction and measurement of best spectacle-corrected visual acuity in eyes with corneal irregular astigmatism such as post-penetrating keratoplasty eyes. Higher-order wavefront aberrations of the cornea were calculated by expanding videokeratography elevation data into Zernike polynomials, and coma and spherical aberrations were computed. For ocular aberrations, the data obtained with the Hartmann-Shack sensor were decomposed into Zernike polynomials. Coma aberrations of the cornea significantly correlated with age, while corneal spherical aberrations showed no age-related changes. The time-course of changes in corneal higher-order aberrations was reported for photorefractive keratectomy and laser in situ keratomileusis (LASIK). For ocular aberrations, the degree of tilting of the suture-fixed intraocular lens significantly correlated with the amount of coma aberration of the eye. In normal eyes, the ocular coma increased with age mainly because of the increase in the corneal coma, and the ocular spherical aberration increased with age because of the increase in spherical aberration in the internal optics including the crystalline lens. The conventional LASIK significantly increased ocular higher-order aberrations, which compromised postoperative contrast sensitivity and low contrast visual acuity. Both corneal and ocular wavefront aberrations were analyzed in cataract, pseudophakic and aphakic eyes, and the equilibrium of spherical aberrations between the cornea and the eye in those conditions was investigated. In pseudophakic eyes, coma aberrations of the cornea, along with the corneal multifocality, significantly contributed to apparent accommodation. Computer simulation indicated that a focus shift of 0.5 diopters deteriorated the retinal image significantly more in eyes without higher-order aberrations than in eyes having a moderate amount of coma aberrations. Clinical results of aspherical intraocular lens were reported for wavefront analysis and contrast sensitivity measurements, and retinal images were analyzed by simulation. For the assessment of vision-related QOL, National Eye Institute Visual Functioning Questionnaire 25 (NEI-VFQ 25) was translated into Japanese. After the validation study, the influence of cataract surgery on QOL was investigated. The QOL score was severely impaired in patients with bilateral cataract, which was significantly and dramatically improved by surgery. Forward scattering, backward scattering, and wavefront aberration induced by the crystalline lens were quantified, and the impact of these factors on visual function was analyzed according to the type of cataract. The degree of QOL improvement by surgery was assessed in relation to the type of cataract and intensity of scattering and aberration. By comprehensively analyzing these factors, quantitative parameters could be developed in the near future to describe progression of cataract and determine the indication for cataract surgery.

Cataract Extraction↗
PubMed2005

[A recurrent rhodopsin gene missense mutation in a Chinese family with autosomal dominant retinitis pigmentosa].

OBJECTIVE: To detect mutation in the rhodopsin gene (RHO) in a Chinese family with autosomal dominant retinitis pigmentosa (ADRP). METHODS: A total of 25 family members from a Chinese family were investigated. All the subjects were examined clinically by direct funduscopy, perimetry and vision test. Evaluation of the proband included electroretinography (ERG). Genomic DNA was extracted using standard method. The complete coding regions of RHO were amplified by polymerase chain reaction (PCR) and the PCR products were subjected to automatic DNA sequencing. RESULTS: 512 C>T (P171L), a recurrent missense mutation was detected in the proband. All 12 affected subjects in the family were heterozygous for the mutation. The affected individuals had night blindness at the age of 5-6 years. They had relatively severe impairment of visual acuity and suffered a gradual loss of peripheral visual field at the age of 20-30 years. And they went blind at the age of 40-50 years. Rod and cone ERG were not detectable in the proband. CONCLUSION: A recurrent missense mutation, 512C>T (P171L), was detected in a Chinese family with ADRP.

Adolescent↗
PubMed2005

[Color vision in glaucoma].

This article is a general view of evaluated acquired color vision defects in the early stages of primary glaucoma and in patients at risk for glaucoma. The articles published until now indicates a decrease in color discriminating sensitivity in the short wavelength part of the visible spectrum in patients with glaucoma as well as in patients with ocular hypertension. It has been found a positive correlation between the blue-yellow color vision defects and the perimetric changes in the glaucomatous eyes. Blue-yellow color vision testing with the anomaloscope may serve as an additional test in the early diagnosis of glaucoma but the absence of dyschromatopsia does not exclude the disease.

Color Perception↗
PubMedDate not supplied

When should children have their eyes checked?

Timely screening for the early detection of eye and vision problems in children is vital to avoid lifelong visual impairment. Early detection provides the best opportunity for effective treatment. Organizations devoted to the health and well-being of children have issued recommendations or policy statements regarding the timing of eye screenings and examinations. The American Academy of Pediatrics (AAP), American Association of Pediatric Ophthalmology and Strabismus (AAPOS), American Academy of Ophthalmology (AAO), American Association of Certified Orthoptists (AACO), and the American Academy of Family Physicians (AAFP) recommend screening at birth and all well-child visits. The American Optometric Association (AOA) recommends that vision examinations begin at 6 months of age. All children found to have an ocular abnormality or who fail vision assessment should be referred to an eye care specialist trained to treat pediatric patients.

Age Factors↗
PubMedDate not supplied

Refractive error profile--a clinical study.

AIM: To study the distribution of refractive error in different ethnic groups of Nepal. METHODS: A total of 1276 new eye patients between 5-35 years of age were included in this study after a thorough eye examination consisting of vision test, anterior and posterior segment eye examination including the investigative procedures whenever needed to rule out any systemic and ocular diseases. Thereafter, the patients were subjected to rigorous streak retinoscopic refraction. RESULTS: Out of 1276 eye patients examined 51.33 % patients are males and 48.66 % are females. The ethnic distribution of refractive error shows that there are 32.44% Newars; 27.50% Brahmins; 21.63% Chhetriyas; 12.14% Gurungs, Magars, Rais, Limbus, Tamangs, Sunuwars; and 6.26% Madhesias. Out of 414 Newar patients, 14.00% patients are myopic; 29.71% hyperopic; and 56.28% astigmatic. In 351 Brahmin patients, 14.81% patients are myopic; 49.85% hyperopic; and 35.32% astigmatic. In 276 Chhetry patients, 13.40% patients are myopic; 48.18% hyperopic; and 38.40% astigmatic. Out of 155 Gurungs, Magars, Rais patients, 11.61% are myopic; 52.90% hyperopic; and 35.48% astigmatism. Out of 80 Madhesias patients, 11.25% are myopic; 37.50% hyperopic; and 51.25 % astigmatic. CONCLUSION: Thus, a refractive error profile is drawn up in Nepalese population.

Adolescent↗
PubMed2006

Ocular toxicity of ethambutol.

OBJECTIVE: To review the literature on ocular toxicity of ethambutol--its background, clinical presentation, toxicity characteristics, management, monitoring, and preventive measures. DATA SOURCES: Literature search of Medline from 1962 to May 2005. STUDY SELECTION: All related literature in English using the search formula: (ethambutol OR myambutol) AND (eye* OR ophthal* OR ocular) AND (adverse OR toxic). DATA EXTRACTION: All information was collected and analysed by authors. DATA SYNTHESIS: Ethambutol hydrochloride is a commonly used first-line anti-tuberculous agent. Although rare, ocular toxicity in the form of optic neuritis (most commonly retrobulbar neuritis) has been well documented since its first use in the 1960s. Classically described as dose- and duration-related and reversible on therapy discontinuation, reversibility of optic neuritis remains controversial. International guidelines on prevention and early detection of ethambutol-induced ocular toxicity have been published. Nonetheless, opinion of the clinical effectiveness of regular vision tests to enable early detection of toxicity is divided. CONCLUSIONS: The course of ethambutol-induced ocular toxicity is unpredictable. Measures to ensure a high level of awareness in medical staff and patients of this potential adverse effect appear to be the best current preventive method. Classified by the World Health Organization as a place with an intermediate tuberculosis burden and good health infrastructure, Hong Kong is in a good position to examine the unanswered questions about ethambutol-induced ocular toxicity.

Antitubercular Agents↗
PubMed2006

[The dependence of the range of fusion on some selected functions of the visual system. Part I: Study on convergent and divergent fusion].

After examined 132 patients, the authors selected 90 patients with correct visual acuity of both eyes, correct range of eyeballs' mobility, parallel setting of the eyeballs, no difference in refraction between both eyes and with muscular balance. These 90 patients were divided into 3 groups: children between 8 and 10 years old, teenagers between 11 and 20 years old and adult people between 21 and 40. All the groups were subject to the main examination of the study carried out by means of prism bar and synoptophore for each of the eye separately. The results were compared in order to define the difference in the range of fusion between both eyes. The study involved an examination of horizontal range of convergent and divergent synoptophoric fusion as well as that of free space for near and for far. A statistically significant difference between both eyes was observed in range of synoptophoric, for near and for far convergent fusion. The difference was confirmed in an average of 35.6% of patients for convergent fusion for near, in 34.4% of patients for convergent fusion for far, and in 65.6% of patients for synoptophoric convergent fusion. The mean difference between the eyes in the range of fusion was: 4.6 degrees for convergent fusion for near, 3.9 degrees for convergent fusion for far and 6.4 degrees for synoptophoric convergent fusion. No significant differences between both eyeballs were detected in the range of divergent fusion. The authors suggested calling the phenomenon connected with the difference between both eyeballs in convergent fusion the following term: "visual unevenness of the range of convergent fusion".

Adolescent↗
PubMed1991

Severe allergic keratoconjunctivitis and erythema multiforme after a routine eye examination: discerning the cause.

Acute allergic dermatitis of the eyelids with keratoconjunctivitis is associated with a specific triggering factor. Therapy for the acute inflammation can complicate the search for such a factor if the process worsens. We report a case of acute contact dermatitis and keratoconjunctivitis after a routine eye examination to demonstrate the difficulty in evaluating such patients and the role of skin patch testing in determining the cause.

1-Propanol↗