Despite the continuing threat of amblyopia, the prognosis for a good visual outcome after cataract surgery in children has improved over the last few decades. Not only has there been a refinement of the surgical techniques and technology, there has also been an improvement of our understanding of the sensitive periods for the development and reversal of amblyopia. Age at onset, laterality (unilateral versus bilateral), and associated ocular and systemic diseases are important nonmodifiable factors influencing visual outcomes. On the other hand, duration of deprivation, correction of residual refraction, and amblyopia therapy are, at least in part, modifiable factors influencing visual outcome. Table 46.1 describes factors associated with visual outcome after pediatric cataract surgery.

The literature on visual outcomes in pediatric cataracts presents a wide spectrum of results. The heterogeneous nature of the data makes comparison of the studies very difficult. For example, it is difficult to compare two studies when (1) Study A’s inclusion criteria are age at surgery <1 years, while study B states <18 years; (2) Study A’s inclusion criteria are age at last follow-up >5 years, while study B includes patients at any age; (3) Study A involves the majority of unilateral cataract cases in contrast to study B that has a majority of bilateral cataracts, and the laterality of the cataract is not accounted for in the analysis of either study; (4) Study A includes pediatric traumatic and other complicated cataract, while study B lists them as an exclusion criteria; (5) Study A is reporting visual outcome of only those with quantifiable visual acuity (VA), while study B has reported overall median visual outcome; (6) Study A has follow-up range from 1 month to 1 year, while study B includes those who have minimum follow-up of 1 year; and (7) Study A uses an ETDRS chart, while study B uses an HOTV chart. To make matters worse, for bilateral disease, some studies include data from both eyes, without considering the correlation effect in statistical analysis, while others have randomly selected one eye of bilateral cataract patients for analysis. Some studies have reported the mean of LogMAR VA in contrast to others reporting an arithmetic mean of denominator of Snellen VA or of decimal VA. As seen above, readers should pay particular attention to methodology including the inclusion-exclusion criteria.

We reported the visual outcome (measured at age 4 and older) of pediatric eyes that underwent cataract extraction with primary intraocular lens (IOL) implantation.¹ One-hundred and thirty nine eyes met inclusion criteria. Median age at surgery was 5.1 years (range, 0.03-16.9); the median age at last follow-up was 9.0 years, and the median follow-up was 3.6 years. The median corrected distant VA was 20/30. Forty-five patients had a final VA worse than 20/40. Of these, 34 (76%) had a diagnosis of amblyopia as the sole cause. Lim and colleagues reported the outcome of 778 patients (1,122 eyes) diagnosed with cataract over 10 years. Including only patients with quantifiable VA, the authors found that a final VA of 20/30 or better was observed in 39%.²

Age at cataract development is significantly associated with adverse visual outcome. Age at the cataract diagnosis is not necessarily the age at which the cataract developed. Screening and detection of cataracts at the earliest is very useful. Birch and Stager reported that when cataracts are dense at birth, there exists only a 6-week window of time beginning at birth, during which treatment of a dense congenital unilateral cataract is maximally effective.³ However, even late operated cataracts get some functional visual outcome. In 1842, Stafford reported a case of congenital cataract where sight was acquired by operation at the age of 23 years.⁴ The authors reported that the acquisition of sight was very gradual. At first, all was confusion. The 3rd week the patient began to distinguish objects and to be conscious of the differences of one thing from another. The patient was aware, when a piece of rag was waved before her eye, that something
was moving backward and forward. In a month, she differentiated black and white from color. Her knowledge of form and color rapidly improved.

The eyes of patients who have bilateral cataracts have a better prognosis after surgery than do the eyes of those affected by unilateral cataracts. In 1956,⁵ Crawford reported, “I have today seen a patient who makes one feel more cheerful about the results of operation for congenital cataract. Both eyes were operated on at about the age of 15, at Moorfields, by Mr. Adams. The patient is now aged 90 and with glasses can see 6/9 with the right eye and 6/6 with the left, and can read the smallest print with comfort. He has sought advice only because one of these venerable spectacles has been broken.” The presence of a sound, healthy eye frequently causes a delay in presentation, diagnosis, and treatment. Patients who have unilateral cataracts also have a higher incidence of coexisting ocular defects. In the past, some argued whether it is worth operating eyes with unilateral cataract as most children were not benefited from surgery. Now, we know that although treatment is frequently frustrating, functional visual outcome may be achieved in some children with monocular cataract. Chak and colleagues⁶ reported a median postoperative VA of 6/60 in unilateral and 6/18 in bilateral disease. Median age at surgery was 2.99 months in unilateral and 4.6 months in bilateral cases. We reported median VA of unilateral and bilateral cases being 20/40 and 20/25, respectively.¹ Hussin and Markham evaluated the visual outcome of IOL implantation after cataract surgery in children. The examination for the prospective part of this study included the recording of VA. Mean final VA for the unilateral group was 0.91 logMAR, and for the bilateral group, it was 0.57 logMAR (Snellen equivalent 20/162 and 20/74, respectively).⁷