Case Report

Cataract surgery in a monocular amblyopic patient

Midgley, Kirsten J. MD*; Miller, Alyssa M.; Ullman, Michael A. MD; Wells, Kevin MD; Fleischer, Eric MD

Author Information
Journal of Cataract and Refractive Surgery Online Case Reports: January 2018 - Volume 6 - Issue 1 - p 10-11
doi: 10.1016/j.jcro.2017.11.001
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Abstract

Amblyopia affects approximately 3% of the population.1 As cataract surgery becomes more accessible and patient outcomes continue to improve, the decision of when to operate on cataracts in amblyopic eyes is not always clear. This debate is especially significant in monocular patients because there is an increased risk for the same degree of benefit after cataract extraction. We report a case of a newly monocular patient after trauma, with the fellow remaining eye having apparent dense amblyopia. The patient had cataract surgery in the amblyopic eye with visual restoration beyond expectations.

CASE REPORT

A 67-year-old African American man with a medical history of type II diabetes mellitus, hypertension, hyperlipidemia, renal transplantation, and metastatic tonsillar and neck squamous cell carcinoma status post-excision and radiation presented with a posterior ruptured globe after falling and hitting the left eye on the corner of a table. Emergent primary closure of the ruptured globe was performed. The patient's right eye was amblyopic and had poor vision since childhood. Although no previous records were available to confirm the severity of the amblyopia, the patient had performed all activities of daily living, working, and driving with the left eye.

The patient's traumatized left eye was initially light perception postoperatively but declined to no light perception at follow-up. The patient's baseline vision was counting fingers at 1 foot in the right eye. He was corrected to 20/400 with a −16.00 diopter (D) spherical refractive error. He was offered low-vision services and monitored closely.

Throughout the postoperative monitoring of the left eye, the patient said he felt as though the vision in the right eye had progressively worsened. He was concerned that he was now unable to see and not able to work because of his new visual impairment. The patient did have a likely visually significant cataract in his right eye, although not dense enough to explain the corrected 20/400 measured visual acuity.

The providers had a long discussion with the patient regarding unknown visual potential and the increased risk associated with performing cataract surgery in a monocular patient. The patient decided to move forward and had uneventful cataract extraction with implantation of a single-piece +6.0 D Acrysof SN60WF intraocular lens (Alcon Laboratories, Inc.) in the capsular bag without complication. One week postoperatively, the patient's corrected distance visual acuity was 20/30 in the right eye. He was able to return to work, drive, and live independently.

DISCUSSION

It is common in monocular patients with visually significant cataract to wait longer to have surgery. Their monocular status confers a greater risk for reduced vision as a result of surgical complications.

Although it is believed that the critical period for visual development and reversal of amblyopia closes in childhood, there is evidence that adult patients with amblyopia can regain vision.2–7 El Mallah et al.2 studied the changes in visual acuity in amblyopic eyes after the development of unilateral choroidal neovascularization as a result of age-related macular degeneration in the fellow dominant eye. This report cites this pathological process as form of “natural occlusion” in the previously healthy eye. In their study, 9 patients had a history of amblyopia previously documented by ophthalmologists or personal ocular history and initially presented with a mean Snellen equivalent visual acuity in the amblyopic eye of 20/320. By the 12-month follow-up, the visual acuity in the amblyopic eyes improved by 3 lines on average.2 As a different form of occlusion therapy, Wilson3 found improvement in the visual acuity in 2 amblyopic eyes when the fellow eyes became cataractous. Similarly, Klaeger-Manzanell et al.4 described a case in which a 44-year-old patient with amblyopia had marked visual improvement 4 months after a penetrating eye injury in the other eye.

Levi and Polat5 found an average 46% improvement in Vernier acuity after training in 6 adults with naturally occurring amblyopia. Simmers and Gray6 measured several parameters in 2 amblyopic patients older than the previously accepted age for occlusion treatment; the parameters included high-contrast and low-contrast logarithm of the minimum angle of resolution Crowded Acuity, repeat letter acuity, and hyperacuity measurements. Before intervention, a functional loss in each of these tests was seen. Occlusion therapy intervention appeared to improve all parameters measured in the amblyopic eyes.6 These studies provide different methods of occlusion therapy with results that suggest plasticity of the visual system much later into adulthood.

Recent evidence has shown that amblyopic eyes are very sensitive at detecting blur and glare despite a reduced visual acuity and contrast sensitivity.A These symptoms can be increased with the progression of cataracts. It is not known to what extent this affects amblyopic patients with cataract; however, previous studies have shown improvement in postoperative visual acuity. In particular, in the National Cataract Surgery Survey 1997–1998,8,9 50% of amblyopic patients achieved a visual acuity at discharge of 20/40 or better compared with 77% of those without amblyopia. Harrad et al.A reported comparable results in 43% of amblyopic eyes versus 50% of other patients reviewed). Interestingly, white cataracts were found in 11.5% of amblyopic eyes versus 3% of nonamblyopic eyes, and 75% of those postoperative complications in amblyopic eyes were associated with white cataracts. This is consistent with most providers waiting, perhaps for an unnecessarily long time, to operate on amblyopic eyes.

This case serves as a reminder of the importance of carefully evaluating cataracts in amblyopic patients before making the decision to operate but that delaying surgery unnecessarily might increase the risk for complications associated with dense cataract. Avoiding unnecessary complications in our patient was especially imperative because this surgery was the only measure left for visual restoration. This case highlights preoperative considerations and potentially life-changing outcomes that we as ophthalmologists can make.

Disclosures:

None of the authors has a financial or proprietary interest in any material or method mentioned.

REFERENCES

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4.Klaeger-Manzanell C, Hoyt CS, Good WV. Two step recovery of vision in the amblyopic eye after visual loss and enucleation of the fixing eye. Br J Ophthalmol 1994; 78:506-507. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC504842/pdf/brjopthal00030-0086.pdf. Accessed November 22, 2017
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7.Polat U. Restoration of underdeveloped cortical functions: evidence from treatment of adult amblyopia. Restor Neurol Neurosci 2008; 26:413-424
8.Desai P, Minassian DC, Reidy A. National cataract surgery survey 1997-8: A report of the results of the clinical outcomes. Br J Ophthalmol 1999; 83:1336-1340. Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1722910/pdf/v083p01336.pdf. Accessed November 22, 2017
9.Desai P, Reidy A, Minassian DC. Profile of patients presenting for cataract surgery in the UK: National data collection. Br J Ophthalmol 1999; 83:893-896. Available at: http://bjo.bmj.com/content/83/8/893.full.pdf. Accessed November 22, 2017

OTHER CITED MATERIAL

A.Harrad RA, Tole D, Waterfall J, “The Outcome of Cataract Surgery in Amblyopia,” presented at the annual meeting of the Association for Research in Vision and Ophthalmology, Fort Lauderdale, Florida, USA, April 2008. Abstract available in Invest Ophthalmol Vis Sci 2008; 49:2831. Available at: http://iovs.arvojournals.org/article.aspx?articleid=2378242. Accessed November 22, 2017
© 2018 by Lippincott Williams & Wilkins, Inc.
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