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L R Achiron

Publications and source records attributed to L R Achiron.

7 recordsLinked to original sources
PubMed1998

The effect of relative spectacle magnification on aniseikonia.

PURPOSE: The purpose of this article is to study the effects of modifying relative spectacle magnification to determine what effect this has on aniseikonia, binocularity, and visual comfort. METHODS: A prospective analysis of 34 aniseikonic patients was undertaken. The etiology of aniseikonia varied from physiologically occurring to induced. Aniseikonic screening included manifest refraction, keratometry, axial length, Randot stereoacuity, associated phoria, and Keystone space eikonometry. A modified pair of spectacles was fabricated on the basis of magnification principles for iseikonic lenses. Each patient was also given a control pair of conventional spectacles. A 4-week trial period was allowed for each pair of spectacles, pertinent examination measurements were repeated, and a patient survey was administered. Data were analyzed by t-test and chi-square. RESULTS: Modifying relative spectacle magnification reduced mean aniseikonic error by 1.06% (P < 0.0001). A difference was found between the control and modified spectacles for subjective reports of visual comfort, performance, and eye-strain (P < 0.05). There was no difference between the two groups for stereoacuity or cosmetic appearance of lenses. At the conclusion of the study, 93% of patients preferred the modified lenses in direct comparison. CONCLUSIONS: Our results confirm that modification of lens designs to equalize relative spectacle magnification reduces aniseikonia and improves subjective comfort and performance of anisometropic spectacles.

Adult↗
PubMed1995

The illuminated high contrast macular grid: a pilot study.

BACKGROUND: Analysis of visual disturbances in the central 10 degrees provides valuable data for the low vision clinician. Amsler grid testing in the visually impaired can be poorly visible and it can be difficult to transcribe results. Automated perimeters will accurately map retinal defects, but the equipment is expensive and this technique is time consuming. An Amsler grid was modified using principles of luminance and contrast to improve its accuracy, and its efficacy was compared to an automated perimeter. METHODS: Eighteen visually impaired patients (28 eyes) were prospectively evaluated at the Emory Low Vision Laboratory. Each patient had three central threshold visual field tests: automated perimetry (Humphrey model 690), conventional Amsler Grid, and Illuminated High Contrast Macular Grid (IHCMG). The Humphrey central 10-2 threshold automated visual field examination was performed to map the patient's retinal function. RESULTS: The Humphrey analysis identified (mean +/- one standard deviation) 2.4 +/- 1.4 defects per patient with an average percent defect area of 33.4 +/- 14.8 degrees. The IHCMG technique was not significantly different from the Humphrey technique for identifying the number of defects (2.25 +/- 1.5) (p > 0.05) or the percent defect area (26 degrees +/- 20 degrees) (p > 0.05). The conventional Amsler grid technique significantly under-evaluated the retinal defects compared to the Humphrey analysis of the number of defects (p < 0.01) and percent area of defects (p > 0.001). CONCLUSIONS: The IHCMG technique can be used as a simple, rapid and accurate analysis of the central 10 degrees visual field in the low vision patient.

Aged↗
PubMed1994

Postinfectious hepatitis B optic neuritis.

A 41-year-old female nurse's aide presented with a recent history of viral hepatitis B. Approximately 1 month after her liver functions had normalized she developed symptoms of optic neuritis with painful loss of vision and optic disc edema. Her laboratory studies revealed evidence of systemic vasculitis and glomerulonephritis. A discussion is presented of the patient's clinical course and a brief history of the systemic effects of acute hepatitis B infection (HBV); the pathophysiology for HBV-induced autoimmune optic neuritis (ON), management guidelines, and differential diagnoses are discussed.

Acute Disease↗
PubMedDate not supplied

Contemporary management of aniseikonia.

The diagnosis and management of aniseikonia has become a lost art. Refractive surgery and intraocular lens implantation has created a new patient population of anisometropia. Measurement of aniseikonia through instrumentation such as the space eikonometer is not readily available. Therefore, estimating the degree of aniseikonia based on the dioptral differences between the two eyes may be the most practical approach. The optical principles of spectacle magnification can be translated by the prescribing eye doctor to reduce ocular image disparity. Contemporary lens designs, such as hi-index and aspherics, allow the practitioner to modify shape and power factors to achieve higher levels of aniseikonic correction in a cosmetically fashionable pair of spectacles.

Aniseikonia↗
PubMedDate not supplied

The use of dissimilar progressives in the management of presbyopia.

The management of anisophoria with bifocal spectacle correction has always presented a challenging refractive problem. Historically, practitioners have used dissimilar bifocal segments or bicentric grinding to neutralize induced vertical imbalance. We present a method of reducing anisophoria at near point with dissimilar progressive multifocals. By incorporating different progressive designs, anisophoria can be minimized to a tolerable level, based on the dioptric power of lens and progressive lens design.

Adult↗
PubMedDate not supplied

Monocular diplopia related to asymmetric corneal topography after laser in situ keratomileusis.

PURPOSE: To show a specific relationship between monocular diplopia and corneal refractive asymmetry after laser in situ keratomileusis (LASIK). METHODS: One hundred thirty-eight eyes of 98 patients who underwent LASIK for myopia between -2.12 and -17.75 D were examined under room-lighted conditions. We examined 51 eyes at 2 weeks, 46 eyes at 3 months, 32 eyes at 6 months, and 9 eyes at 1 year after LASIK. We attempted to correlate the presence of monocular diplopia with their corneal topographical features. RESULTS: Eight eyes of five patients (five eyes at 2 weeks, three eyes at 3 months after LASIK) produced symptoms of monocular diplopia. These symptomatic patients had a common corneal topographical feature caused by decentralized or inhomogeneous ablation. Every pupillary area in the patients' topographies contained steeper and flatter areas. The range of refractive power variation in these asymmetric areas was at least 1.50 D. The location of the secondary image correlated with the direction of the steeper area in all eight eyes. Pinhole viewing eliminated or reduced the prominence of secondary images in every case. CONCLUSION: Monocular diplopia following LASIK appears to correlate with postoperative corneal refractive power variation inside the pupillary area, caused by decentralized or inhomogeneous ablation.

Adult↗