The outcomes of cataract surgery in functionally monocular patients have been studied extensively at the Jules Stein Eye Institute, University of California–Los Angeles (UCLA). Monocular patients are often referred to us for evaluation and management, presumably because the operative risks in these patients, particularly for bilateral blindness, are higher than in functional 2-eyed patients. The decision to perform cataract surgery at UCLA is generally made in accordance with the guidelines of the preferred practice patterns of the American Academy of Ophthalmology.1 According to the guidelines, “The indications for surgery in the functionally monocular patient are the same as for other patients; that is, when the cataract-impaired vision no longer meets the patient's needs and the anticipated benefits of surgery exceed the risks.”
In 1 UCLA study, Bergwerk and Miller2 report a consecutive case series of 93 functionally monocular patients in whom phacoemulsification and intraocular lens (IOL) implantation were performed. They identified good visual outcomes for most patients, a high degree of ocular comorbidity, and a low rate of perioperative complications. Trotter and Miller,3 also at UCLA, report a subsequent case-control study with 100 patients per group that confirms the findings of Bergwerk and Miller.2 In the Trotter and Miller study, monocular and binocular patients gained a mean of 3 lines of best corrected visual acuity (BCVA). The 2-week postoperative and final BCVA were slightly better in binocular patients (20/20) than in monocular patients (20/25) because there was more preexisting macular disease in the monocular group. Trotter and Miller found statistically greater ocular comorbidity in the eyes of monocular patients and a greater need for planned and unplanned additional procedures at the time of cataract surgery (eg, pupil stretch and trabeculectomy). They noted a similar rate of operative complications in both groups. In another UCLA study, Pomberg and Miller4 found that monocular patients experience twice as much improvement in functional vision as binocular patients, as measured by a 14-question visual function questionnaire (VF-14), despite identical gains in BCVA.4
From these observations, we generally argue that it is not in the best interest of monocular patients to withhold cataract surgery until a significant visual handicap is present, which is a common historic practice. According to preferred practice patterns,1 “Delaying surgery until the cataract is very advanced may increase surgical risk and retard visual recovery.” Notwithstanding, favorable results in large groups of patients do not diminish the “all or none” effect when an individual patient experiences a serious complication.
We describe a monocular patient who experienced the most severe complication of cataract surgery—bilateral blindness.
In October 2001, a 74-year-old man came to us with complaints of deteriorating vision in the left eye. The BCVA in the left eye was 20/40; a combined 2+ nuclear, 1+ cortical, and 1+ posterior subcapsular cataract explained the reduction in visual acuity. He had no light perception (NLP) in the right eye and was wearing an ocular prosthesis. The left eye was under treatment for chronic open-angle glaucoma using topical timolol and latanoprost. The intraocular pressure (IOP) was 13 mm Hg, and the vertical cup-to-disc ratio was 0.4. The IOP was as high as 30 mm Hg before treatment was started. The macula was unremarkable. An observational approach was advised because the patient was monocular.
The vision in the patient's right eye was lost to exudative complications of age-related macular degeneration (ARMD) including vitreous hemorrhage, ghost cell glaucoma, and retinal detachment. After multiple surgeries, the eye became phthisic.
In January 2002, the patient returned complaining that his vision was slowly becoming darker. He described difficulty reading and driving and instability walking because of the poor vision. No changes were observed in visual acuity, macular status, or under slitlamp examination. Cataract surgery was scheduled because of the patient's functional complaints. A preoperative retinal consultation was arranged, but only mild pigmentary changes in the macula were noted. No clinical evidence of choroidal neovascularization (CNV) or pigment epithelial detachment was found. Fluorescein angiography was not performed.
In March 2002, clear corneal cataract surgery was performed (K.M.M.) under topical anesthesia using the Kelman phacoemulsification technique. An Alcon single-piece, foldable IOL was implanted in the capsular bag. The day after surgery, the uncorrected visual acuity was 20/50+, improving to 20/40 with pinhole. Two weeks after surgery, the BCVA was 20/40−. Dilated examination of the ocular fundus disclosed a large pigment epithelial detachment involving the macula (Figure 1). Fluorescein angiography revealed a choroidal neovascular membrane inferior to the fovea (Figure 2).
Immediate macular laser photocoagulation was performed but failed to close the neovascular membrane. The patient developed a submacular hemorrhage and several subsequent complications. Four pars plana vitrectomies were performed, but the eye ultimately had NLP. The patient and his family have had a difficult time adjusting to the profound vision loss.
Many things are clearer in hindsight. It may have been better for this patient if we had delayed cataract surgery and obtained a preoperative fluorescein angiogram. Had this been done, the subsequent course might not have been better but we would have done as much as possible to prevent it. Unfortunately, nothing in the preoperative retinal examination suggested subretinal CNV (ie, no visual distortion, retinal elevation, or subretinal hemorrhage). Macular pigmentary changes were minimal. From the size of the membrane 2 weeks after surgery, we must assume it was present preoperatively. The lack of preoperative examination findings in this case raises the question of whether all ARMD patients, especially those who are monocular, should have fluorescein angiography before cataract surgery to rule out the presence of occult CNV. We are unaware of a study that answers this question.
Our case also raises the question of how aggressive an ophthalmologist should be when considering an elective surgical procedure in a functionally monocular patient. Cataract surgery outcomes in monocular patients are generally favorable in the short term.2–4 A quality-of-life or cost-utility approach would naturally favor better vision now over better vision later. Early restoration of vision means fewer workdays lost, fewer accidents, less deterioration in daily living activities, and other benefits, each with financial and psychosocial implications. For patients with significant media opacities, early cataract surgery increases the odds that fundus pathology will be detected and that it will be easier to treat lesions by laser photocoagulation. Related to the quality-of-life issue, monocular patients routinely seek attention and surgical intervention at a level of disability that functional 2-eyed persons can cope with more easily. The reason for the difference is that most binocularly sighted patients have a better-seeing fellow eye to aid their functional vision.
The case-control study by Trotter and Miller3 reveals interesting findings about vision loss after cataract surgery in monocular patients. First, only a few patients (6 of 100) in the study lost vision at the mean follow-up of 11.2 months. Four of the 6 patients lost 1 line of Snellen acuity. Three of them had ARMD, and 2 had CNV that was documented and treated preoperatively. The BCVA loss in some patients was offset by improved glare tolerance and contrast sensitivity. The acuity in the 2 patients with the worst results dropped from 20/30 to 20/100 and from 20/80 to counting fingers, respectively. The eyes of these 2 patients had a progression of advanced open-angle glaucoma. In no case was vision loss a direct consequence of cataract surgery.
Epidemiologic evidence suggests a possible causal relationship between cataract surgery and late-stage ARMD, as defined by the development of CNV or geographic atrophy. Data from 2 large population-based cohorts, the Beaver Dam Eye Study and the Blue Mountains Eye Study, were pooled for analysis.5 The authors found that the adjusted odds of developing late-stage ARMD were 5.7 times greater in pseudophakia than phakia.5 Neither cohort had many pseudophakic patients, and preoperative fluorescein angiography was not performed. Analysis of combined data from the Salisbury Eye Study, the Proyecto Vision Evaluation and Research study, and the Baltimore Eye Survey also produced a weakly significant odds ratio of 1.7 for the development of late-stage ARMD in the presence of pseudophakia.6 Neither report could address the issue of causality. An association between cataract surgery and late-stage ARMD can also result from a selection bias or shared risk factor.
To our knowledge, this is the only report in the literature of a monocular patient becoming completely blind after cataract surgery. We searched the PubMed online database of the National Library of Medicine using all logical search terms (blindness, monocular, cataract surgery). We did not search offline in journals published before 1980.
This case has not changed our general approach to the management of monocular patients. We look carefully for ocular comorbidity when we see a monocular patient, and we try to ensure that all concomitant ocular disease (eg, diabetic retinopathy, glaucoma, ARMD) has been adequately managed before we recommend cataract surgery. However, as a result of this patient, we are more likely to obtain a fluorescein angiogram to screen for occult CNV if the fellow eye has had significant complications related to ARMD.
1. Masket S, Fine IH, Kidwell TP, et al. Cataract in the adult eye. Preferred Practice Patterns. San Francisco, American Academy of Ophthalmology, 2001
2. Bergwerk KL, Miller KM. Outcomes of cataract surgery in monocular patients. J Cataract Refract Surg 2000; 26:1631-1637
3. Trotter WL, Miller KM. Outcomes of cataract extraction in functionally monocular patients; case-control study. J Cataract Refract Surg 2002; 28:1348-1354
4. Pomberg ML, Miller KM. Functional visual outcomes of cataract extraction in monocular versus binocular patients. Am J Ophthalmol 2004; 138:125-132
5. Wang JJ, Klein R, Smith W, et al. Cataract surgery and the 5-year incidence of late-stage maculopathy; pooled findings from the Beaver Dam and Blue Mountains Eye Studies. Ophthalmology 2003; 110:1960-1967
6. Freeman EE, Munoz B, West SK, et al. Is there an association between cataract surgery and age-related macular degeneration? Data from three population-based studies. Am J Ophthalmol 2003; 135:849-856