A 56-year-old man has diplopia following cataract surgery. What may have caused it? interactiveCase diplopia,catarct,catarcat,cataract,catarract,catarcts,catarcact,cataracts,vision,catarracts,cataeract,cateracts,double,diploplia,catarac Author and Series Editor: David K. Coats, MD <b>David K. Coats, MD</b>, Associate Professor of Ophthalmology and Pediatrics, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine; Chief of Ophthalmology, Texas Children's Hospital, Houston, Texas <BR> Medscape Medscape Ophthalmology 08/07/2003 4 2 <H3>History</H3><FONT SIZE="2"><p>A 56-year-old man was referred by his comprehensive ophthalmologist for evaluation of vertical diplopia following cataract surgery with intraocular lens (IOL) implantation in his right eye. He had undergone surgery 1 year earlier and noted diplopia on the first postoperative day. His diplopia was relieved with a slight chin-up posture and was worse on upgaze. Because his job required extensive use of upgaze, he was very symptomatic. He had no history of prior diplopia, and the problem had been stable and unchanged since onset. There were no associated signs or symptoms, and prism therapy had been unsuccessful in relieving his symptoms.</p> <p>His best-corrected visual acuity was 20/25 in each eye. Anterior segment examination revealed a well centered, in-the-bag posterior chamber IOL in the right eye and a mild-to-moderate nuclear cataract in the left eye. Posterior segment examination was unremarkable. Motility evaluation revealed an intermittent right hypertropia of 5 prism diopters, worsening significantly in upgaze (see below).</font><p><table border="0" cellpadding="3" cellspacing="1" width="100%" bgcolor="#EEEEEE"><tr valign="top"><td width="100%" align="center"><b>Click on image to view video.</b></td></tr><tr valign=top> <td width="50%" align="center"><a href="art-mop459267.mov.html" target="Figure" onclick="resizeWin('Figure', 433, 475)"><img src="art-mop459267.mov.gif" width="200" height="136" alt="Movie" border="1"></a></td><tr valign="top"><td width="100%" align="center"> Video of ocular versions, demonstrating limited upgaze in the left eye.</td></tr><tr valign="top"><td width="100%" align="center"><b><a href="http://www.apple.com/quicktime/" target="_blank">Quicktime</a> required to view videos</b></td></tr></table><p><FONT SIZE="2"><h4 align="center">Diagnostic Positions of Gaze</h4> <center> <table border="1" cellpadding="3" cellspacing="1"> <tr valign="top"> <td>&nbsp;</td> <td align="left">RHT 20</td> <td align="left">&nbsp;</td> </tr> <tr valign="top"> <td align="left">RH(T)3, X(T)2</td> <td align="left">RH(T)5, X(T)2</td> <td align="left">RH(T)flick</td> </tr> <tr valign="top" > <td align="left">&nbsp;</td> <td align="left">Ortho</td> <td align="left">&nbsp;</td> </tr> </table></center></font><p><h4>1. Diplopia following cataract surgery can occur as a result of:</h4> <FONT SIZE="2"><blockquote><a href="ans1.html" target="Answer" onclick="resizeWin('Answer',200,375)">A) Surgically induced trauma</a><br><br><a href="ans2.html" target="Answer" onclick="resizeWin('Answer',200,375)">B) Unmasking of a previously existing disorder</a><br><br><a href="ans3.html" target="Answer" onclick="resizeWin('Answer',200,375)">C) Intraocular lens related issues</a><br><br><a href="ans4.html" target="Answer" onclick="resizeWin('Answer',200,375)">D) All of the above</a><br><br></blockquote></font><BR><P><H3>Clinical Course</H3><FONT SIZE="2"><p>Further examination disclosed moderate enophthalmos of the left eye, with Hertel exophthalmometer readings of 18.5 and 15 mm in the right and left eyes, respectively. An occult blowout fracture of the left orbital floor was suspected. Further discussion revealed a history of facial trauma while playing sports as a child, but no previous diplopia.</p> <p>Computed tomography scan of the orbits revealed findings consistent with an old fracture of the medial orbital wall and floor with displacement of the medial rectus muscle in his unoperated left eye (Figure 1). Repair of the blowout fracture has been offered to the patient to correct his enophthalmos, followed by strabismus surgery, if needed, to correct his diplopia.</p></font><p><center><img src="art-mop459267.fig1a.jpg" width="400" height="318" BORDER="1"></center><p><center><img src="art-mop459267.fig1b.jpg" width="400" height="318" BORDER="1"></center><p><FONT SIZE="2"><blockquote><b>Figure 1.</b> Computed tomography demonstrating soft tissue abnormalities in the nasal and inferior orbit of the left eye associated with old blowout fractures, 2 views.</blockquote></font> <P><H3>Discussion</H3><FONT SIZE="2"><p>Diplopia following cataract surgery is uncommon, but not rare. Johnson^[1] reported an incidence of vertical diplopia of 0.23% following cataract surgery performed with retrobulbar anesthesia. Goldnick and colleagues^[2] reported a persistent change in ocular alignment after cataract surgery in 7% of patients, though only 0.85% (1 in 118) experienced symptomatic diplopia in this relatively small series. Hamad^[3] has characterized postcataract surgery diplopia as falling into 1 of 4 main categories:</p> <ol> <li>Diplopia induced by surgical trauma;</li> <li>Unmasking of a pre-existing disorder;</li> <li>Misalignment caused by prolonged visual deprivation induced by the cataract; or</li> <li>Anomalies produced by the pseudophakic state.</li> </ol> <p>The list of possible causes of surgically induced postoperative diplopia is extensive. Retrobulbar and peribulbar injection have been reported to be associated with postoperative diplopia due to anesthetic toxicity to the extraocular muscles.^[4,5] Studies have demonstrated that any rectus muscle, including the superior rectus muscle, can be damaged by retrobulbar injection.^[6] Damage to rectus muscles from bridle suture placement has also been reported. Other less common causes include surgically induced polycoria and cornea irregularities, such as scars or astigmatism.</p> <p>Vision that is severely reduced may prevent a patient from being aware of diplopia from ocular misalignment until vision has been improved following successful cataract surgery. Pre-existing superior oblique palsy has been reported to cause diplopia, as have thyroid-related ophthalmopathy and intermittent exotropia. We have seen occult blowout fractures as the cause of postoperative diplopia in 2 patients following cataract surgery, including the patient in this report. Cataract-induced visual deprivation may also result in loss of control of latent strabismus previously controlled by fusion. Improvement of vision following cataract surgery is often insufficient to allow restoration of fusion, and strabismus surgery is often needed. Sensory strabismus can also be induced by prolonged cataract-induced visual deprivation, and may require strabismus surgery.</p> <p>Finally, pseudophakia has the potential to produce diplopia via a variety of mechanisms, including issues related to multifocal lenses, lens malposition, and induced anisometropia.</p></font><p><P> <ol> <li>Johnson DA. Persistent vertical binocular diplopia after cataract surgery. Am J Ophthalmol. 2001;132:831-835. <a href="http://intapp.medscape.com/px/medlineapp/getdoc?pmi=11730645&cid=med">Abstract</a></li> <li>Golnik KC, West CE, Kaye E, Corcoran KT, Cionni RJ. Incidence of ocular misalignment and diplopia after uneventful cataract surgery. J Cataract Refract Surg. 2000;26:1205-1209. <a href="http://intapp.medscape.com/px/medlineapp/getdoc?pmi=11008049&cid=med">Abstract</a></li> <li>Hamad LM. Strabismus presenting after cataract surgery. Ophthalmology. 1991;98:247-252. <a href="http://intapp.medscape.com/px/medlineapp/getdoc?pmi=2008285&cid=med">Abstract</a></li> <li>Brown SM, Coats DK, Collins ML, Underdahl JP. Second cluster of strabismus cases after periocular anesthesia without hyaluronidase. J Cataract Refract Surg. 2001;27:1872-1875. <a href="http://intapp.medscape.com/px/medlineapp/getdoc?pmi=11709263&cid=med">Abstract</a></li> <li>Paysse EA, Coats DK. Disintegration of the inferior rectus muscle during strabismus surgery for restrictive hypotropia. Ophthalmic Surg Lasers. 2000;31:328-330. <a href="http://intapp.medscape.com/px/medlineapp/getdoc?pmi=10928671&cid=med">Abstract</a></li> <li>Capo H, Roth E, Johnson T, Munoz M, Siatkowski RM. Vertical strabismus after cataract surgery. Ophthalmology. 1996;103:918-921. <a href="http://intapp.medscape.com/px/medlineapp/getdoc?pmi=8643247&cid=med">Abstract</a></li> </ol>