| OBJECTIVE: To provide an explanation for diplopia and the inability to fuse in some patients with macular disease. methods: We identified 7 patients from our practices who had binocular diplopia concurrent with epiretinal membranes or vitreomacular traction. A review of the medical records of all patients was performed. In addition to complete ophthalmologic and orthoptic examinations, evaluation of aniseikonia using the Awaya New aniseikonia Tests (Handaya Co Ltd, tokyo, japan) was performed on all patients. RESULTS: All patients were referred for troublesome diplopia. Six of the patients had epiretinal membranes and 1 had vitreomacular traction. All 7 patients had aniseikonia, ranging from 5% to 18%. In 5 of the patients the image in the involved eye was larger, and in the other 2 patients it was smaller than in the fellow eye. All patients had concomitant small-angle strabismus and at least initially did not fuse when the deviation was offset with a prism. Response to optical management and retinal surgery was variable. CONCLUSIONS: aniseikonia caused by separation or compression of photoreceptors can be a contributing factor to the existence of diplopia and the inability to fuse in patients with macular disease. Concomitant small-angle strabismus and the inability to fuse with prisms may lead the clinician to the incorrect diagnosis of central disruption of fusion. Surgical intervention does not necessarily improve the aniseikonia. ( info) |
2/15. Contact lens management of aniseikonia and photophobia induced by trauma. PURPOSE: To describe a case of a contact lens fitting to relieve aniseikonia and photophobia resulting from trauma. methods: A 61-year-old man suffered a blunt injury to his left eye resulting in glaucoma and a traumatic cataract with a fixed pupil and iris defects. A vitrectomy, lensectomy, and iris repair were performed leaving him with significant anisometropia. RESULTS: The patient was fitted with a prosthetic contact lens. CONCLUSIONS: contact lenses can provide significant visual improvement in cases of aniseikonia and photophobia. ( info) |
| PURPOSE: aniseikonia is a binocular anomaly in which the two eyes perceive images of different sizes and/or shapes. It is usually assumed to be constant as a function of visual field angle (VFA) (i.e., angular distance from the line of sight). This is correct for optically induced aniseikonia, such as the aniseikonia that is associated with anisometropia and probably also pseudophakia. The purpose of this article is to show that if the aniseikonia is of retinal origin, then the aniseikonia may no longer be constant as a function of VFA (i.e., field-dependent aniseikonia). DESIGN: Case report, with the patient having a unilateral epiretinal membrane. methods: The aniseikonia was measured in vertical and horizontal directions with a customized version of the aniseikonia Inspector software. The VFA was made variable by changing the dimensions of the comparison targets in the direct comparison procedure. MAIN OUTCOME MEASURE: aniseikonia as a function of VFA. RESULTS: The patient exhibited good repeatable aniseikonia, ranging from 23% to 2.5% for VFAs ranging from 0.36 degrees to 5.7 degrees . Higher angles had lower aniseikonia. A control subject did not show this field-dependent aniseikonia. CONCLUSIONS: aniseikonia may vary with VFA due to a retinal cause such as an epiretinal membrane. The problem with field-dependent aniseikonia is that it cannot be corrected fully with conventional optics, which exhibit an approximately constant magnification as a function of VFA. Nevertheless, by correcting 5% to 10% aniseikonia, which showed up in the VFA measurement range at 2 degrees to 3 degrees , our patient had improved visual comfort, especially for reading. ( info) |
4/15. Influence of extraocular muscle imbalance on binocular performance. In assessing binocular performance, it is possible that extraocular coordination is more significantly involved than presently recognized. Dynamic phorometry or phorometric testing in the nine cardinal directions of gaze is advised for evaluating the extraocular muscular system. These case reports used interrelation of phorias to evaluate binocular problems. The interpretation of these data helps determine the amount of horizontal prism necessary to reduce compensating vergences. Although a control group was not used, the elimination of associated vertical fixation disparity in these cases seemed to ameliorate binocular stress. ( info) |
5/15. Binocular function in unilateral aphakia. Correlation with aniseikonia and stereoacuity. aniseikonia and stereoacuity were measured in patients with unilateral aphakia, most of whom were postoperative senile cataract cases. The New aniseikonia test was used to evaluate aniseikonia and the Titmus Stereotest to measure stereoacuity. Ninety cases were studied, 57 (63.3%) of which had intraocular lens (IOL) implants; 27 (30%) had extended-wear soft contact lenses; and six (6.7%) had spectacle lenses. In the IOL group, aniseikonia averaged 2.8%, and 39 patients (68.4%) had good stereoacuity. In the contact lens group, aniseikonia averaged 4.6%, and 11 (40.7%) had good stereoacuity. In the spectacle lens group, aniseikonia averaged 17.8%; none of the patients had good stereoacuity. The authors concluded that in cases with unilateral aphakia, correction with an IOL implant is superior to the other alternatives in achieving good binocular function. ( info) |
6/15. Binocular vision complications after radial keratotomy. Radial keratotomy (RK), a popular procedure for reducing myopia, does not always have a successful outcome. Of the adverse effects reported in the literature, there have been few reports of undesirable disturbances of binocular vision. Four representative cases are reviewed which presented clinically with varying binocular problems induced by RK. The treatment considerations and final solutions for each are discussed. In the presence of RK-induced anisometropia, aniseikonia can be a particularly debilitating binocular vision problem for some patients. ( info) |
7/15. Anisophoria after implantation of an intraocular lens. After extracapsular cataract extraction, a Simcoe-style posterior chamber intraocular lens was implanted in the left eye of a 69-year-old patient. The visual acuity of the right eye was 20/25 with 3.0 diopter correction. Probably as a result of a biometric error, the left eye was rendered myopic (-1.75 -3.00 X 25 degrees). This anisometropia caused a disturbing diplopia, which could be explained by anisophoria rather than by aniseikonia. The problem of anisophoria is discussed, along with suggestions for correcting the problem. ( info) |
8/15. Prescribing glasses for myopia. myopia is a one-symptom refraction problem: blurring of distance vision. Correction of the myopia should eliminate this symptom, but a prescription for glasses may, in fact, produce other symptoms equally--or more--disturbing. A few of the more common pitfalls in prescribing for the myopic patient are: (1) failure to recognize accommodative stress masquerading as low myopia; (2) confusion as to when, or whether, to prescribe for the unilateral myopic patient; (3) overcorrecting the myopic refractive error and failure to appreciate the symptoms that result from overcorrection; (4) difficulties in gaining acceptance of bifocals by the myopic presbyopic patient; (5) appropriate selection of bifocal segments; and (6) acquired myopic anisometropia caused by sclerosis of the crystalline lens. Although myopia would appear to be the least troublesome of all refractive problems, the maximizing of visual potential with comfort and safety needs refracting skills, experience, and clinical judgement. ( info) |
9/15. The ultrastructure of well-healed lenticules in keratomileusis. Two well-healed hyperopic keratomileusis homoplastica lenticules, one 4 years old, the other 5 months old, were removed from the same patient following postoperative complications of triplopia and aniseikonia. The lenticules were examined by light and electron microscopy. Both lenticules were repopulated with keratocytes throughout the lamellae. Degenerated keratocytes were observed in the 5-month-old lenticule and recipient stroma, and in the 4-year-old lenticule; no degenerated keratocytes were seen in the recipient stroma of the 4-year-old lenticule. These findings may have resulted from toxic constituents of the solutions used to preserve the donor cornea. The basement membrane was thickened in both lenticules. The epithelial cell layer was irregular in the periphery of the lenticule where Bowman's membrane was disrupted. These findings suggest that careful surgical technique that minimizes damage to Bowman's layer and basement membrane may promote more rapid epithelial healing. The histologic results suggest that the cause of this patient's triplopia was irregular astigmatism. ( info) |
10/15. Electrophysiological detection of aniseikonia. Steady-state and transient Visually Evoked Responses (VERs) were used to verify a paradoxical aniseikonic condition in an anisometropic patient. Testing on the Remole multimeridional horopter apparatus indicated that a 2% overall magnification was required for the more hyperopic eye to eliminate ocular image size differences. A special lens correction for the patient's aniseikonia resulted in a very significant improvement in visual comfort and binocular function. ( info) |