Double Vision as a Presenting Symptom in Adults Without Acquired or Long- Standing Strabismus

Double Vision as a Presenting Symptom in Adults Without Acquired or Long- Standing Strabismus Sara Shippman, C.O. Larisa Heiser, C.O. Kenneth R. Cohen, M.D., F.A.C.S. Lisabeth Hall, M.D. ABSTRACT Background: Evaluation of adults with a symptom of acquired double vision is a challenging diagnostic problem. This retrospective report reviews a series of adult patients who presented with a symptom of double vision but did not have diplopia related to a recently acquired or decompensated strabismus. The symptom of double vision was related mainly to blurred vision and often was not true binocular diplopia. Methods: This is a retrospective study of medical records. Results: 261 patients, age 40 years or older referred for a recent onset symptom of double vision were reviewed. Sixty- seven patients were included in the study. These patients presented with no findings that indicate a recent onset of incomitance or breakdown of a long- standing strabismus. The patients were divided into five groups with common etiologies and their findings were analysized. Group 1 (17 patients) had symptoms of double vision due to monocular blur without diplopia. Group 2 (21 patients) had symptoms of double vision related to monocular blur that caused a dissociation of a small phoria. Group 3 (10 patients) had symptoms of double vision related to superimposition of images due to a distorted image. Group 4 (13 patients) had symptoms of double vision related to convergence insufficiency. Group 5 (6 patients) had symptoms of double vision related to an induced tropia secondary to anisometropia correction. Options for treatment include improving vision and having the patient understand the nature of the problem. Conclusion: Double vision does not mean the same thing to the patient and the examiner. The examiner must distinguish true diplopia from other symptoms and be able to demonstrate this to the patient. Treatment is directed to the specific type of problem, but improvement of vision resolves the large majority of these complaints. Examination and treatment techniques are discussed. From the New York Eye and Ear Infirmary, New York Medical College, New York, New York. Requests for reprints should be addressed to: Sara Shippman, C.O., New York Eye and Ear Infirmary, 310 E. 14th St., New York, NY 10003; e- mail: sshippman@nyee.edu INTRODUCTION Adults who present with a recent onset of a symptom of double vision are a challenging diagnostic problem. As examin- 2008 Board of Regents of the University of Wisconsin System, American Orthoptic Journal, Volume 58, 2008, ISSN 0065-955X, E-ISSN 1553-4448 92

SHIPPMAN ers, we assume the problem is binocular diplopia usually caused by a recent onset of strabismus related to neurological or systemic disease. Descriptions of some other causes of acquired diplopia include decompensation of a longstanding strabismus, 1,2 switching fixation in a patient with strabismus, 3 5 and strabismus surgery. 6 The patients that composed our retrospective study were referred for evaluation of their symptom of double vision. METHOD We retrospectively reviewed charts of all private adult patients who were referred to The New York Eye & Ear Infirmary Orthoptic Department from January 2001 through April 2004 for evaluation of a symptom of recent onset double vision. We selected from this group only those patients who had a symptom of double vision but had no findings to indicate a recent onset of incomitant strabismus or any history or findings of a previous strabismus problem. Examination included vision assessment, ocular preference, cover- uncover testing, Maddox rod testing, fusional tests, and stereopsis assessment. Determination of preference was performed by asking the patient to identify their preferred eye. If the patient was unable to answer, the patient was asked which eye he / she used to take a picture using a camera, or when shooting a gun. Then the patient was asked to monocularly view a 20 / 100 letter through a small hole in a piece of paper. Three responses indicating the preferred eye were possible. If the patient put the hole immediately in front of one eye and did not move it, this was the preferred eye. If the patient put the hole over one eye and then switched to the other (usually the better seeing eye) then the preferred eye was the first eye. Lastly, if the patient asked which eye they were supposed to put the hole in front of, this indicated their preferred eye was the blurred eye. RESULTS Two hundred sixty- one patients presented with a symptom of double vision between 1 / 01 / 2001 and 4 / 30 / 04. One hundred ninety- four patients were excluded from the study because of a recent onset cranial nerve palsy related to a neurological or systemic problem, trauma, an incomitant strabismus related to retinal surgery, a history of preexisting strabismus or strabismus surgery, or incomitant strabismus following cataract surgery. Sixty- seven patients were included in the study. There were 36 females and 31 males, ranging from age 40 to 90, with the average age of 67 years. We divided these 67 patients into five groups based on the etiology of the symptom of double vision. There was some overlap of causes so the patients were placed in a group thought to be the main etiology of the symptom of double vision. Group 1 (17 patients) had symptoms of double vision due to monocular blur without any associated diplopia. Group 2 (21 patients) had symptoms of double vision related to monocular blur that caused a dissociation of a small commitant phoria. Group 3 (10 patients) had symptoms of double vision due to image distortion causing superimposition of images rather than fusion. Group 4 (13 patients) had symptoms of double vision related to blurred vision associated with convergence insufficiency. Group 5 (6 patients) had symptoms of double vision related to anisometropic correction, causing an anisophoria (Table 1). Group 1, the monocular blur group, consisted of 17 patients. They had symptoms of double vision that were intermittent and due to a monocular blur without associated diplopia. The visual acuity in the blurred American Orthoptic Journal 93

DOUBLE VISION TABLE 1 GROUPS Symptoms True Group # of pts of DV* Diplopia 1 Monocular blur 17 + 2 Dissociated phoria 21 + + 3 Superimposition type double vision 10 + + 4 Convergence insufficiency 13 + + 5 Anisometropia 6 + Total 67 * DV - double vision eye ranged from 20 / 25 to 20 / 100 in the involved eye; 14 patients had blurred vision in the preferred eye, and three patients had blurred vision in the nonpreferred eye. The reasons for the blurred vision were uncorrected hyperopia (5 patients), uncorrected myopia (3 patients), refractive blur related to monovision (4 patients), poorly fitting glasses with bifocals or poorly fitting contact lenses (2 patients), and cataracts (3 patients). Fourteen patients had horizontal phorias ranging from 1 16 Δ and three patients had vertical phorias ranging from 1 2 Δ. With appropriate examination techniques all patients realized that the symptom of double vision was not diplopia but a monocular blur (Table 2). Treatment included reevaluation for the cause of monocular blur. This ranged from cataract removal, adjusting glasses and bifocals, refitting contact lenses, or discontinuation of monovision. Once the monocular blur was corrected, the symptom of double vision was resolved in all patients in this group (Table 3). Group 2 consisted of 21 patients who had monocular blurred vision with dissociation of a small comitant horizontal or vertical deviation causing diplopia. Vision ranged from 20 / 30 to 20 / 100 in the blurred eye. Sixteen patients had blurred vision in the preferred eye, one patient had more blur in the nonpreferred eye, and four patients with blur had no eye preference. Monocular blur causing dissociation of the devia- tion was due to cataract (8 patients), monovision (3 patients), uncorrected refractive error (8 patients), and poor positioning of the progressive bifocal (2 patients). Six patients had comitant horizontal deviations ranging from 2 10 Δ and 15 patients had a comitant vertical deviation ranging from 1 8 Δ (Table 2). Treatment for 21 of the patients consisted of improving vision, which led to improved control of the deviations and resolution of the diplopia. Treatment included full- time glasses, elimination of monovision, discontinuing the use of a progressive bifocal, or cataract surgery. In addition, seven patients out of 21 needed prism in the glasses for deviations ranging from 1 5 Δ of vertical deviation for five patients, and 2 10 Δ of esotropia for two patients. Four of the seven had symptoms of double vision before their first cataract operation. Their symptoms resolved quickly after the first cataract was removed, but returned after the second cataract was extracted. Group 3 consisted of 10 patients who had symptoms of double vision due to image distortion causing superimposition of images without fusion. Because the images were not fused, the blurred image would float away resulting in diplopia. The patients described the symptom of double vision as a clear image with a superimposed shadow, followed by diplopia. Vision ranged from 20 / 30 to 10 / 200 in the more blurred 94 Volume 58, 2008

SHIPPMAN TABLE 2 RESULTS Horizontal Vertical Group Blurred eye Vision deviation deviation Fusion 1. Monocular blur P*=14 (82%) 20 / 25 20 / 100 1 Δ 16 Δ 1 Δ 2 Δ 17pts (17 pts) N** = 3 (18%) 20 / 40 20 / 80 14pts 3 pts 2. Dissociated phoria P=16(76%) 20 / 30 20 / 100 2 Δ 10 Δ 1 Δ 8 Δ 21pts (21pts) N = 1 (5%) 20 / 50 20 / 70 6pts 15pts NA***= 4(19%) 20 / 20 20 / 25 3. Superimposition P=4 (40%) 20 / 70 10 / 200 2 Δ 8 Δ 1 Δ 6 Δ None type double (distortion) 20 / 30 20 / 70 6pts 4pts vision (10 pts) N = 6 (60%) (distortion) 4. Convergence P=2(15%) 20 / 30 20 / 100 10 Δ 15 Δ none 13pts insufficiency N=4(31%) 20 / 30 20 / 40 13pts (13 pts) None=7(54%) 20 / 25 20 / 40 5. Anisometropia NA*** 20 / 20 20 / 40 NA*** NA*** 6pts (6 pts) * P - Preferred eye ** N - Nonpreferred eye *** NA - None applicable eye. Four patients had decreased vision and distortion in the preferred eye. Six patients had decreased vision and distortion in the nonpreferred eye. All patients had central visual problems causing distortion either due to macular degeneration, glaucoma, or a retinal problem. The horizontal deviation in six patients was 2 8 Δ and 4 patients had vertical deviations from 1 6 Δ (Table 2). Because fusion with a prism was not possible, treatment was directed to either ignoring / suppressing the blurred image or increasing the blur of the distorted image. Seven patients were able to ignore the distorted image. Three patients were unable to ignore the image. Treatment for one of these three patients included a Bangerter occluder on the lens over the blurred eye, and a prism to keep the distorted image within a visual field defect in the remaining two cases (Table 3). Group 4, the convergence insufficiency group, consisted of 13 patients with true diplopia at near due to convergence in- sufficiency with an intermittent exotropia [X(T)] at near fixation. Vision ranged from 20 / 30 to 20 / 100 in the blurred eye. Two patients had blur in the preferred eye, four patients had blur in the nonpreferred eye, and seven patients had equal vision with glasses but did not wear glasses full time. The X(T) at near ranged in size from 10 15 Δ (Table 2). Treatment for one patient consisted of full- time reading glasses. Nine patients underwent convergence treatment, and three patients needed base- in prism for reading in addition to convergence treatment (Table 3). Group 5, the anisometropia group, consisted of six patients who experienced vertical diplopia as they looked off the optical center due to the induced prism effect of glasses. The patient s anisometropia ranged from two to five diopters of difference between the lenses. Vision was 20 / 20 to 20 / 40. Three patients anisometropia occurred after unilateral cataract extraction, and three patients had anisometropia American Orthoptic Journal 95

DOUBLE VISION TABLE 3 TREATMENT Group Treatment 1. Monocular blur wear glasses(8), refit contact lenses(2), discontinue monovision(4), (17 pts) treatment of cataracts(3) 2. Dissociated phoria discontinue monovision(3), full Rx with bifocals(8), treatment of (21pts) cataracts(8), change type of bifocals(2), prisms(7) 3. Superimposition ignore second image(7), blur second image(1), prisms to move double vision (10 pts) second image(2) 4. Convergence glasses full time(1), exercises(9), prisms(3) insufficiency (13 pts) 5. Anisometropia contact lens(1), adjust glasses(1),using monovision(1) prisms(3) (6 pts) secondary to poorly fitting glasses (Table 2). Treatment methods included contact lenses, cataract extraction in the fellow eye, better fitting glasses, or monovision (Table 3). COMMENTS These groups of adult patients, who present with a symptom of double vision, in the absence of incomitant strabismus represent an interesting and challenging diagnostic and treatment group. Though one thinks of a symptom of double vision as diplopia related to an incomitant strabismus or a breakdown or change of a longstanding strabismus, these patients had other causes for the symptom of double vision mainly monocular diplopia or blurred vision. Kushner evaluated and discussed monocular diplopia that presents as diplopia, but only with patients who had a history of strabismus. He gives examples of many of the same causes that we found in our patient groups. 1 Pratt- Johnson also gives an excellent description of monoc - ular diplopia and its causes in all types of patients. 5 By looking at this particular series of adult patients, we were able to clinically distinguish that the symptom of double vision was usually related to monocular blurred vision. The importance of equal- izing and optimizing vision as well as explaining the difference between monocular blur and diplopia to the patient is clearly demonstrated in Groups 1 and 2. Thirty- one patients in these two groups of 38 patients were relieved of their symptom of double vision by correcting the vision in the blurred eye. In Group 2, the unilateral blurred vision affected the visual input enough to cause dissociation of a physiologic phoria and true diplopia. Jampolsky has discussed this unequal visual input affecting fusion and has shown how blurred vision can dissociate phorias. 7 Though seven patients did need prisms in their glasses, most patients (14 of 21) recovered control of their small comitant deviations just by equalizing the vision. Fusion was restored in all patients other than those with superimposition of a distorted image (Table 2). If the monocular blur is in the preferred eye, it seems to cause more symptoms than if the nonpreferred eye is blurred. In the first two groups, composed of 38 patients, 30 patients (78.9%) had blurred vision in the preferred eye. Seven of our patients (four in Group 1 and three in Group 2), were symptomatic due to the blur of the preferred eye in monovision. Eye preference was not as important in Group 3. Whether in the preferred or nonpreferred eye, distortion due to macular 96 Volume 58, 2008

SHIPPMAN problems is very different than a blurred image, and fusion is not possible. The images would be superimposed and then would float apart. Other authors have also found a difference between blur and distortion with regards to their affect on fusion. 1,7 In Group 4 (convergence insufficiency), though eye preference did not seem to be as important, maintaining clear or equal vision in both eyes seemed to be integral to control of the X(T). Ten patients regained control of their X(T) with reading glasses and convergence treatment. In Group 5, the anisometropia group, detecting the cause of the double vision was more difficult because the vision was equal. The patients real complaint was intermittent diplopia when looking off primary position due to the induced prism in the glasses. The induced tropia was often difficult to detect and to explain to the patient. The easiest method to detect and explain it was to show the patient the difference in the deviation with and without glasses with the use of a Maddox rod test. Once the examiner and patient appreciated the change in size or direction of the deviation with the glasses on and off, the treatment approach was easier to explain. Contact lenses, equalizing the refraction by cataract surgery, or slab- off prism in a bifocal served to resolve the problem for these patients. The use of progressive bifocals to eliminate the visible line of a traditional flattop bifocal has also caused problems for patients due to the distortion and blur in the side areas adjacent to the intermediate column. Conversion to a flat- top bifocal was successful in treatment of several patients. Regardless of the clinical treatment of the problem, both the patient and the examiner must realize and understand the difference between monocular blur and diplopia. Examination techniques will clearly differentiate monocular blur from true diplopia. Showing the patient that the symptom goes away when the involved eye is occluded, but not with occlusion of the fellow eye is necessary so the patient understands what they are seeing is a monocular blur with a shadow. By inducing a tropia, causing true diplopia and having the patient observe that one of the images is still blurred with a shadow, the patient may recognize the difference between monocular blur and true diplopia. Lastly, if the patient has the symptom of double vision at near with reading, which is often the situation, a stereo test can be administered. If the patient has stereopsis but the numbers on the test book are blurred, the difference between blur and true diplopia is easily illustrated. CONCLUSION In summary, many patients who present with the symptom of double vision do not have diplopia. Recognition of this and its clear explanation to the patient is essential to the rectification of the problem. This group of patients is hard for the examiner to evaluate and treat because the patient often finds it very difficult to recognize and understand the difference between blur and diplopia. These patients are referred because of their complaint of what they call double vision, and are already confused about the diagnosis. Because of this confusion between double vision due to monocular blur and true diplopia, the patient is often unable to understand and cooperate with the treatment of the problem. Restoration of clear vision, especially in the preferred eye, most often solves the problem. It does not seem to matter if the method involves surgery for cataract, contact lens fitting or accurate prescription of well- fitting glasses. The use of prism glasses should American Orthoptic Journal 97

DOUBLE VISION be deferred until this avenue of treatment, restoration of clear vision, has been fully explored. REFERENCES 1. Kushner BJ: Recently acquired diplopia in adults with long- standing strabismus. Arch Ophthalmol 2001; 119:1795 1801. 2. Rutstein RP, Bessant B: Horror fusionis: A report of five patients. J Am Optom Assos 1996; 67: 733 739. 3. Kushner BJ: Fixation switch diplopia. Arch Ophthalmol 1995; 113:896 899. 4. Rutstein RP: Fixation switch: an unusual cause for adolescent and adult onset diplopia. J Am Optom Assos 1985; 56:862 865. 5. Pratt- Johnson JA, Tillson G. Management of Strabismus and Amblyopia: A Practical Guide. New York: Thieme Medical Publishers, Inc.; 1994. pp. 242 246. 6. Kushner BJ: Intractable diplopia after strabismus surgery in adults. Arch Ophthalmol 2002; 120:1498 1504. 7. Jampolsky A: Unequal visual imputs and strabismus management: A comparison of human and animal strabismus. In: Symposium on Strabismus. St. Louis: Mosby; 1978. pp. 358 492. Key words: diplopia, double vision, monocular blur, anisometropia Continuing Education Credit Orthoptists wishing to earn American Orthoptic Council approved continuing education credits may earn 5 hours of credit by completing a self-study test based on the articles contained in the American Orthoptic Journal. Allied Health Personnel in Ophthalmology may earn 4 hours of JCAHPO approved continuing education credit upon successful completion of the self-test. Information regarding the test may be obtained by sending an e-mail request to: Jason DeBoer, Managing Editor, jwdeboer@wisc.edu 98 Volume 58, 2008