All About Cataracts

Most cataracts are age-related eye problems and affect people age 50 and older. But cataracts also can be present at or near birth. In these instances, the lens opacities are called congenital cataracts.

Early treatment of congenital cataracts is essential for normal vision development and to prevent amblyopia or blindness.

Researchers in England recently investigated the current status of cataract surgery performed in the UK and Ireland for children age two years and younger.

Surveys were sent to 928 ophthalmologists, with a response rate of roughly 75 percent.

Findings of the study included:

• 47 of the respondents (7 percent) performed congenital cataract surgery on children age 2 and younger.
• Among those performing the surgery, 41 (87 percent) performed primary intraocular lens (IOL) implantation in these children.
• One quarter of respondents said they would not implant an IOL in a child under 1 year old. 

Other reasons surgeons provided for not performing primary IOL implantation included the presence of other eye conditions, including microphthalmos (70% of respondents), anterior eye problems (52 percent), posterior eye anomalies (61 percent), and glaucoma (19 percent).

Microphthalmos is a developmental anomaly characterized by one or both eyes being abnormally small.

The researchers concluded that surgery for congenital cataracts with IOL implantation in children age 2 years and younger has been widely adopted in the UK and Ireland by the relatively small number of ophthalmologists who manage these children.

Among these ophthalmologists, there is general agreement concerning surgical technique, choice of IOL design and the formula used for IOL power calculation. But variation exists in eligibility criteria for IOL implantation, and this may reflect a lack of consensus on which children are most likely to benefit from it and the risks involved.

The researchers also said there is a need for systematic studies of the outcomes of primary IOL implantation in younger children.

Source: Cataract surgery and primary intraocular lens implantation in children 2 years old in the United Kingdom and Ireland: findings of national surveys. British Journal of Ophthalmology. Published online June 16, 2009.

Researchers at Emory Eye Center and Emory Vision (Emory University, Atlanta) recently investigated the outcomes of cataract surgery performed with multifocal intraocular lenses (IOLs). The purpose of the study was to determine reasons for patient dissatisfaction with the procedure and the outcomes after remedial actions are taken.

The researchers reviewed the cases of 32 patients who were dissatisfied with the outcomes of their cataract surgery with multifocal IOL implantation. 

Most eyes (65 percent) had received an AcrySof ReSTOR IOL (Alcon) and the others (35 percent) received a ReZoom Multifocal IOL (Abbott Medical Optics). 

Outcomes analyzed included type of visual complaint, the remedial treatment applied to address the complaint, and the degree of improvement after intervention.

Findings of the study included:

1. Thirty patients (94 percent) reported blurred vision.
2. Fifteen patients (47 percent) reported photic phenomena (visual disturbances caused by optical aberrations; also called “negative dysphotopsia”).
3. Thirteen patients (41 percent) reported both blurred vision and photic phenomena. 

Causes of blurred vision included:

• Posterior capsule opacification, or “PCO” (22 eyes, 54 percent)
• Residual nearsightedness, farsightedness or astigmatism (12 eyes, 29 percent)
• Dry eye syndrome (6 eyes, 15 percent)

Causes of photic phenomena included:

• PCO (12 eyes, 66 percent)
• IOL decentration (2 eyes, 12 percent)
• Retained lens fragment from the removed cataractous lens (1 eye, 6 percent)
• Dry eye syndrome (1 eye, 6 percent)

Remedial treatments applied to relieve patient symptoms included artificial tears and other dry eye therapy, laser surgery for PCO and surgery for IOL exchange.

Thirty-five eyes (81 percent) had improvement with conservative treatment. Five eyes (12 percent) did not have improvement despite treatment combinations. Three eyes (7 percent) required IOL exchange.

The researchers concluded complaints of blurred vision and photic phenomena after multifocal IOL implantation can be effectively managed with appropriate treatment, though a few eyes may require IOL exchange.

The study was supported in part by Research to Prevent Blindness and the National Institutes of Health.

Source: Dissatisfaction after multifocal intraocular lens implantation. Journal of Cataract and Refractive Surgery. June 2009.

Bilateral cataract surgery intentionally designed for monovision produces good visual acuity and high patient satisfaction, according to a study published in the Journal of Cataract and Refractive Surgery. 

Researchers in Australia evaluated the outcomes of cataract surgery performed on both eyes of 26 patients. In all cases, a monovision correction was performed with intraocular lenses (IOLs). The target refractive endpoint of the second eye corrected for near vision was mild to moderate myopia ranging from -1.00 D to -1.50 D. 

Visual acuity, contrast sensitivity, stereopsis, and patient satisfaction were measured prior to surgery and 3 to 4 months post-operatively. Patients were also asked how frequently they needed eyeglasses after surgery.

Monovision is a method of vision correction where one eye is fully corrected for distance vision and the other eye is made (or is left) nearsighted so a person with presbyopia can see acceptably well up close without reading glasses. Monovision can be performed with contact lenses or refractive surgery, including refractive cataract surgery.)

Results of the study included:

1. 96 percent of the patients achieved uncorrected binocular distance visual acuity of at least 20/30.
2. 92 percent achieved approximately 20/30 or better uncorrected near visual acuity. 
3. Good depth perception and contrast sensitivity were maintained after surgery. 

Patients were generally satisfied with their vision after surgery. Approximately 25 percent of patients did not need glasses for any reason; one patient was totally dependent on spectacles. No patient required an IOL exchange or other additional refractive surgery.

The authors of the study concluded monovision cataract surgery achieves good visual function and patient satisfaction without the risk of troublesome visual symptoms sometimes associated with multifocal IOLs used in cataract surgery to correct presbyopia.

Source: Patient satisfaction and visual function after pseudophakic monovision. Journal of Cataract and Refractive Surgery. June 2009.  

Having multifocal intraocular lenses (IOLs) implanted in both eyes for the treatment of cataracts produces better visual outcomes than a single multifocal IOL implanted in one eye, according to a study published in the June 2009 issue of Journal of Cataract & Refractive Surgery.

In the study, an AcrySof ReSTOR multifocal IOL was implanted 1) in one eye of patients with a natural (non-cataractous) lens in the other eye; 2) in one eye of patients who had a conventional monofocal IOL implanted in the other eye; and 3) in both eyes of patients with a cataract in one or both eyes.

Visual acuity, contrast sensitivity and stereopsis (depth perception) of all eyes was measured six months after cataract surgery. Patients also were surveyed about the quality of their vision and their overall satisfaction.

Patients receiving bilateral multifocal IOLs had the highest satisfaction score (92 percent), and 77 percent of these patients achieved spectacle independence after surgery.

Among patients with the multifocal IOL implanted in one eye only, 75 percent reported being satisfied with their vision, and spectacle independence was achieved by 56 percent of patients with a natural lens in their other eye and 65 percent of those who had a monofocal IOL implanted in their other eye.

Patients with bilateral multifocal IOLs also had better uncorrected near visual acuity, stereopsis, best-corrected near vision and best-corrected intermediate vision.

More patients with bilateral multifocal IOLs (77 percent) experienced halos at night compared with patients who received a multifocal IOL in one eye only (57 percent), but in most cases halos were minot and did not significantly affect patients’ overall satisfaction with their visual outcome.