Laser Surgery for Unilateral Amblyopia

A retrospective review compiled by Orucoglu et al from Hadassah - Hebrew University Medical Center, Israel (I Refract Surg 2011),  indicates that laser refractive surgery may be a good option for patients with mild-to-moderate amblyopia from anisometropic myopia, where one eye has a greater degree of myopia than the second eye.  Amblyopia, or "lazy eye," is the most common cause of unilateral visual impairment in adults.  Laser surgery is the procedure most often performed to correct adult ametropia, including mildly amblyopic eyes in the absence of organic disease. 

The study assessed the amblyopic eyes of 30 patients.  At the conclusion of their review, the authors found that in amblyopic eyes, the best spectacle-corrected visual acuity (BSCVA)

• improved >= 1 line in 16 eyes (53.3%), with a maximum improvement of 4 lines
• remained unchanged in 10 eyes (33.3%)
• decreased by 1 or 2 lines in 4 eyes (13.3%)  In the fellow nonamblyopic eyes, the best-corrected visual acuity (BCVA)
• improved by 1 or 2 lines in 9 eyes (30.3%)
• remained unchanged in 16 eyes (53.3%)
• decreased by >=1 line in 5 eyes (16.7%)

The gain of lines of BCVA was significantly greater in the amblyopic eyes group compared with the nonamblyopic eyes.  In addition, laser refractive surgery was effective and safer in amblyopic eyes to correct myopia. 

"In our series, gain in BSCVA after refractive surgery in amblyopic eyes was significantly higher than fellow nonamblyopic eyes," the authors wrote.  "We demonstrated that laser refractive surgery was safe and effective in mild-to-moderate adult amblyopic eyes."

Effects of Undercorrected Astigmatism on Vision

A recent study conducted by Wolffsohn et al from Aston University United Kingdom (J Cataract Refract Surg 2011), revealed that even small amounts of uncorrected astigmatism in post-cataract-surgery patients can have a significant effect on vision quality and if left untreated, can affect the quality of life of older patients.  Uncorrected astigmatism may also contribute substantially to falls among the elderly, the study noted. 

Approximately 85% of the general population has corneal astigmatism and 20%-30% of those >60 years of age have significant astigmatism.  Because cataracts and astigmatism with intraocular lenses (IOLs) offers a viable solution to both cataracts and astigmatism, but many patients do not choose IOLs to correct astigmatism due to added cost. 

"Many public health services consider intraocular lenses that correct astigmatism to be premium," the authors noted.  "Therefore, older patients with coexisting cataract and astigmatism must pay for the IOL as well as the cost of private surgery if they wish to achieve optimum vision."

The study assessed whether leaving patients with uncorrected astigmatism after cataract surgery had an impact on visual acuity and reading speed also decreased with increasing uncorrected astigmatism power.  Light scatter was not significantly affected by uncorrected astigmatism; however, the reliability and variability of measurements decreased with increasing uncorrected astigmatic power.  Driving simulator performance was unaffected by uncorrected astigmatism, although clarity decreased with increasing uncorrected astigmatic power. 

"With modern IOLs implanted after cataract surgery, astigmatism can easily be corrected and the additional cost of these 'premium' IOLs is likely to be far less than the consequences of leaving the patient with uncorrected astigmatism," the authors noted.  "Hence, correction of corneal astigmatism during cataract surgery and IOL implantation should be considered the standard of care."

Cataract Surgery for Patients in Their 90s

Cataract surgery poses no greater risk of ocular complications for patients in their 90s than those in their 80s, according to a recent study of patients treated within the U.S. Veterans Health Administration (VHA).  The study, conducted by Tseng et al from the VA Medical Center, Rhode Island (Ophthalmology 2011), used data from the National Patient Care Database to compare surgical complication rates of 554 nonagenarians and 11,407 octogenarians who received cataract surgery in the VHA.  The authors collected patient demographics and preoperative systemic and ocular comorbidities, and evaluated both intraoperative complications and 90-day postoperative complications. 

A previous study of 45,000 veterans undergoing cataract surgery in the VHA, which evaluated a comprehensive list of comorbidities and ocular complications, found that patients aged >= 80 years were at increased risk for ocular complications after cataract surgery.  This study sought to determine whether patients at the higher end of the age spectrum - those in their 90s - were at greater risk for complications than were patients in their 80s.

For both age groups in this study, diabetes mellitus was the most common systemic comorbidity and age-related macular degeneration the most common ocular cormorbidity.  The study showed that while octogenarians had a higher prevalence of systemic comorbidities overall, nonagenarians were more likely to experience ocular comorbidities.

In both age groups, the most common intraoperative and postoperative complications were vitreous loss or posterior capsular tear and posterior capsular opacification.  The authors noted that within this VHA study population, the risk of having any intraoperative or postoperative complication was 13.5% for octogenarians and 13.4% for nonagenarians.

"This study was not designed to determine criteria for selecting nonagenarians for cataract surgery," the authors wrote.  "However, once the decision has been made to proceed with surgery, [these data] may inform cataract surgeons and their nonagenarian patients regarding the risk of experiencing an ocular complication."  Additional studies are needed to assess how nonagenarians are selected for cataract surgery and to evaluate visual function and quality of life in these patients, the authors added.