As the surgery itself continues its evolution to a refractive surgical procedure, an aging population and changes in our health-care system are contributing to a cataract surgery picture that is in flux. This year’s ARVO abstracts encapsulate some of that activity.
Lens Studies
Surgeons in Glasgow, Scotland, report that an aspheric intraocular lens significantly reduces certain higher-order aberrations. They conducted a prospective, observational study of 50 patients who underwent uncomplicated cataract extraction to evaluate the effectiveness of an aspheric IOL in reducing monochromatic higher-order aberrations (MHOA). They measured whole-eye, corneal and internal MHOA before and four weeks after surgery. Pre- and postoperative data was compared to 300 eyes of 167 age-matched patients with no visually significant cataract. MHOAs were measured over a 5-mm dilated pupil diameter using the iTrace aberrometer. Zernike coefficients were obtained to the 6th order. (See results, below.) There was a significant reduction in total root mean square MHOA following surgery (p<0.001). The RMS of total internal 3rd (p<0.001), 4th (p<0.001), 5th (p=0.033) and 6th (p=0.006) orders also showed a significant reduction postoperatively. Postoperative whole-eye MHOAs (mean 0.484 µm) were found to be significantly less (p<0.001) than age-matched controls (mean 0.648 µm). Postoperative whole eye (mean 0.133 µm) and internal SA (mean 0.071 µm) were found to be significantly less than control cases (mean 0.223 µm; p<0.001 and mean 0.133; p=0.022 respectively).
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French surgeons compared the visual performance of two multifocal diffractive intraocular lenses, AcrySof ReSTOR SN60D3 (Alcon) and Acri.LISA 376D (Carl Zeiss Meditec), two years after cataract surgery.
The prospective, comparative study included patients between 50 and 80 years of age; 20 eyes (10 patients) that received the ReSTOR intraocular lens and 24 eyes (12 patients) that received the Acri.LISA IOL, with bilateral implantation by a single surgeon.
There was no statistically significant difference (α=5 percent) between the two lenses in terms of visual acuity for far and near vision, for monocular and binocular vision, for contrast sensitivity and glare test. There was a statistically significant difference in favor of the Acri.LISA group for intermediate visual acuity, especially for monocular uncorrected VA (p=0.03), binocular uncorrected VA (p=0.041) and binocular corrected VA (p=0.004). The analysis of quality of life questionnaire did not find any statistically significant difference between the two groups nor any correlation between visual discomfort during night driving and glare test.
While both IOLs have similar visual performance (good level of satisfaction without eye glasses), the better intermediate vision in the Acri.LISA group may be explained by the asphericity of the lens increasing the depth of field, the authors surmise. This two-year follow-up data confirms the results of previous studies reported in the literature (six months and one year follow-up).846
A group in Massachusetts sought to establish criteria for determining quality of refractive outcomes after toric IOL implantation and assess whether toric IOLs with higher cylindrical power are associated with inferior refractive outcomes. Reviewing the charts of patients implanted with the Alcon AcrySof Toric IQ lens over three years, they recorded cylindrical power of the IOL; postop uncorrected distance VA (UDVA); postop corrected distance VA (CDVA); postop residual astigmatism by manifest refraction; and presence of ocular comorbidities. Eyes were assigned to groups based on outcomes defined as good (UDVA 20/25 or better with ≤ 0.5 D residual astigmatism), fair (either UDVA 20/30 with ≤ 0.5 D residual astigmatism, or UDVA 20/25 or better with 0.75 D residual astigmatism), and poor (UDVA 20/30 or worse with ≥ 0.75 D residual astigmatism).
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Establishing criteria for determining quality of refractive outcomes with toric IOLs can be helpful in counseling patients before cataract surgery, they conclude. Implantation of higher cylindrical power toric IOLs is associated with slightly more residual astigmatism, but there is no association with inferior postop UDVA.1848
A group in Mexico City assessed the safety and effectiveness of the AcrySof Cachet Phakic angle-supported IOL for the correction of high myopia. The study evaluated 14 eyes of nine patients, age 22 to 53 years, mean 34.1 years; 66.6 percent were female; mean follow-up was 29 months (r: nine to 38 months). The mean preop spherical equivalent was -14.39 (r: -10.25 to -19.25); mean postop SE was -0.5 (r: -3.25 to +0.62). The mean postoperative UCVA was 20/30 (logMar 0.17) or better and the BCVA 20/25 (logMar 0.098) or better. The contrast sensitivity was measured with CDVA, considering the low (6.28 cycles per degree), medium (5.07 cpd) or high (3.78) mean spatial frequencies. The change of the mean preop endothelial cell density (2,763.4 cells) to mean postoperative cell density (2,626.9) was statistically significant (p=0.013). Only one patient was a steroid hyper-reactor; the pressure normalized after the drug was suspended. None of the patients showed IOP rise or other adverse effects.
The group says its results are consistent with other published reports of phakic IOLs, where the UCVA and BCVA were excellent. However endothelial cell loss over time was statistically significant, which has been attributed to the proximity of the anterior chamber IOL to the endothelium, the surgery itself and physiologic decrease with aging.3134
Surgical Issues
Researchers from nine U.S. institutions collected data for the Veterans Administration’s Ophthalmic Surgical Outcomes Data Project to assess the impact of intraoperative floppy iris and the use of pupillary expansion devices on intraoperative complication rates in cataract surgery.
The retrospective analysis recorded the use of alpha-blockers (both selective and non-selective), intraoperative floppy iris, intraoperative iris trauma, intraoperative iris prolapse, posterior capsular tear, anterior capsule tear, intraoperative vitreous prolapse, and use of pupillary expansion devices.
Of 4,923 total cataract surgeries included, 1,294 patients, (26.3 percent) took alpha-blockers preoperatively (selective 627, non-selective 667). Of these 1,294 patients, 428 patients (33.1 percent) had documented IFIS. However, 75.2 percent of patients with IFIS had taken alpha-blockers preoperatively (p<0.00001); 430 patients of the total studied (8.7 percent) had a pupillary expansion device used during their cataract surgery, of which 186 patients had IFIS (43.3 percent, p<0.0001). Seventeen patients had anterior or posterior capsule tears (3 percent); five patients had both. Of patients with posterior capsule tear, 88.2 percent (15/17) had vitreous prolapse that required vitrectomy; only four of these involved the use of a pupillary expansion device (23.5 percent). Thirty-eight patients with IFIS had at least one intraoperative complication, and 18 patients with IFIS had more than one intraoperative complication (p<0.00001). Of these 18 patients with IFIS and more than one intraoperative complication, 27.8 percent (five of 18) had pupillary expansion devices used.
The use of alpha-blockers preoperatively demonstrated a significant risk of IFIS. Less than half of IFIS patients had pupillary expansion devices used during their cases. Approximately half of patients with intraoperative surgical complications and IFIS incurred more than one complication. A prospective trial could be conducted looking at whether the increased use of pupillary expansion devices in high-risk VA patients could decrease intraoperative surgical complication rates.1826
With complete removal of lens epithelial cells recognized as a common strategy to prevent posterior capsule opacification, surgeons in Norfolk and London, U.K., investigated how total LEC loss affects IOL stability within the capsular bag.
Capsular bags were generated from human donor eyes by capsulorhexis and lens extraction followed by implantation of a single-piece Acrysof IOL. Capsular bags with associated zonules and ciliary body were removed from the eye and secured by pinning the ciliary body to a silicone ring. One bag of each pair was treated with 1µM thapsigargin, a calcium ATPase inhibitor, to destroy all LECs. Observations of LEC growth were captured by phase contrast microscopy, and IOL stability was assessed by video microscopy. At end-point, the bags were examined using scanning electron microscopy and immunocytochemistry.
LECs in control capsular bags could be observed to migrate centrally, closing the bag and fixating the IOL between the anterior and posterior capsules, as seen clinically. In addition a firm seal was formed at the rhexis edge between the anterior capsule and the underlying IOL. Application of thapsigargin to the capsular bags prevented cell growth and led to a complete loss of viable cells. Consequently, thapsigargin-treated preparations did not exhibit adhesion between anterior and posterior capsules nor adhesion to the IOL surface. These observations were confirmed by SEM and immunocytochemistry. Following a period of controlled orbital movement, the positioning within the capsular bag was unaffected in each test group. However, the IOLs in the control group stabilized more quickly than in the thapsigargin-treated bags.
They conclude that LECs appear to aid stabilization of current IOL designs in the capsular bag. This study has important clinical implications for IOL design and for strategies to prevent posterior capsule opacification.2975
Scleral fixation of IOLs with fibrin glue has been reported in a few case series in the literature. Potential advantages include relative surgical ease, minimal intraoperative complications and stability of the IOL at follow-up. Surgeons at the University of Ottawa Eye Institute, Ontario, Canada have incorporated this technique into their practice predominantly as a secondary IOL implant procedure in aphakes and as an IOL exchange procedure for patients destined for endothelial keratoplasty. The procedure involves the creation of two partial thickness scleral flaps, 3 mm from the limbus at 180 degrees from each other. A three-piece IOL is inserted, with each haptic being externalized through a sclerotomy under the flap and tucked into an intrascleral tunnel. The flaps are then closed with fibrin glue.
The retrospective review of their first 10 consecutive patients assessed outcomes including complications, centration of IOL, visual acuity, manifest refraction and endothelial cell count. The 10 eyes of nine patients (mean age 63) included eight edematous, pseudophakic bullous keratopathy eyes with poor visibility through the cornea, which had an IOL exchange procedure in which the offending primary anterior chamber IOL was replaced by a glued IOL, later followed by EK. The remaining two eyes were treated for traumatic lens subluxation. There were no intraoperative complications, and pain symptoms resolved within one week postoperatively. At one-month follow up, nine of 10 eyes had a centered IOL, with the remaining patient having inferior subluxation. One eye with preexisting glaucoma had an IOP rise to 54 mmHg, which was managed with topical therapy.2991
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The study reviewed outcomes of 30 eyes of 24 patients. Twelve had a history of RK and 18 had previous myopic/hyperopic LASIK/PRK. Biometry measurements were obtained preoperatively. The IOL power was calculated using the SRK/T or Holladay 1 formula and the ASCRS Post Keratorefractive IOL calculator. The ORA-recommended IOL power, the actual implanted IOL power, and the postoperative UCVA and manifest refraction were recorded. IOL back-calculation for emmetropia was done using previously published formulas.
Mean postop UCVA was 20/40. Mean postop SE was 0.07D (r: -1.75 to +4.5 D). There was a significant difference between the mean postoperative SE in the LASIK/PRK and RK groups (-0.31 and 0.63 respectively, p=0.039). (See other outcomes above.)
The ORA’s ability to predict IOL power was significantly better in LASIK/PRK patients than in RK patients (p=0.0064).3004
Surgeons at Chicago’s Northwestern University used spectral domain anterior segment optical coherence tomography to analyze the morphology of clear corneal incisions performed in patients undergoing femtosecond laser-assisted cataract surgery (Catalys, Optimedica).
An intended triplanar incision was programmed into the Catalys. The first plane was at 90 degrees to the corneal surface and extended to 40 percent corneal depth, the second was an angled intrastromal plane and the third plane was at 45 degrees to the posterior corneal surface and reached the second plane at 70-percent depth. The intended incision width was 2.85 mm and length was 1.8 mm. AS-OCT was performed on the first postop day. The clear corneal incision length, incision depth, angles of the tri-planar corneal incision, and wound gaping were measured using software calipers. The variability in wound length, depth and angle were calculated and compared to the programmed software settings. Five architectural features were used to describe the clear corneal incisions: gaping of the wound at the epithelial side; gaping of the wound at the endothelial side; within-wound gape; misalignment of the roof and floor of the incision at the endothelial side; and local Descemet’s membrane detachment. This study is ongoing and will include 30 eyes.
At one day postop, two of three eyes had endothelial side wound gape; one of three had epithelial wound gape, two of three eyes had a within-wound gape; and three eyes had a focal DM detachment. All three eyes had visible three-plane profile on AS-OCT. The clear corneal incision length was within 100 µm of the intended length. The incision depth was within 8 percent of the intended depth.
While initial results suggest that CCIs using the femtosecond cataract laser were close to the intended size and depth, a significant proportion of eyes had marginal and stromal wound gape and focal DM detachment.563
Femtosecond cataract surgery appears to be safe and effective in high-risk cases of lens exfoliation syndrome, and may hold an intrinsic advantage of less surgical zonular weakening associated with capsulorhexis and lens fragmentation, according to a group from New York University.
In 65 eyes of 48 consecutive patients with LES, the group recorded preoperatively and three months postoperatively: age; UCVA; BSCVA; refraction; cylinder; capsulorhexis diameter; topographic cylinder change; endothelial cell count; and possible complications. (An endocapsular tension ring was used in five cases.)
The mean age was 71 years. The mean pre- and postop values were as follows:
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Demographics, Miscellaneous
A Duke University study concludes that white patients and those with private insurance tend to present with better preoperative best-corrected visual acuity, on average, than their respective counterparts at the time of cataract surgery. The findings may represent a disparity in access to care or utilizing the care based on insurance and race variables. Larger studies are needed to confirm these preliminary findings.
Over the four-year study, the researchers collected data on visual acuity, race, gender, health insurance plans, systemic and ocular comorbidities, body mass index and smoking history on 430 candidates for cataract surgery.
Insurance (uninsured, public, private) and race (white, black, other) were the two sociodemographic variables with significant differences between groups (p<0.0001 and p=0.0005, respectively). Significant differences in mean preop BCVA were found for private (Snellen~20/55) versus public (20/75, p=0.0001); private versus uninsured (20/150, p=0.0003); white (20/60) versus black (20/75, p=0.0008); and white versus other race (20/105, p=0.0138). There was no significant difference in BCVA between public and uninsured, black and other race, or men and women, and no strong correlations between BCVA and BMI or smoking pack-years. In a multivariate regression model adjusting for age, significant comorbidities from univariable analyses (diabetes, age-related macular degeneration and hypertension), and other vision-impairing conditions, insurance and race remained significant (p=0.0056, 0.0038).857
Incident cataract surgery steadily has increased over the last three decades, and second-eye surgery is performed sooner and more frequently, based on data from the Rochester Epidemiology Project collected and analyzed by researchers at Minnesota’s Mayo Clinic.
The data came from 8,012 cataract surgeries from 2005 through 2011. During this time, incident cataract surgery significantly increased (p<0.001), peaking in 2011 with an overall incidence rate of 1,100 per 100,000 residents. The probability of second-eye surgery was 60 percent at three months after first-eye surgery, 76 percent at 12 months and 86 percent at 24 months; this was an increase of >30 percent when compared to the same time intervals in the previous seven-year period, 1998 to 2004 (p<0.001). When merged with previous REP data, incident cataract surgery steadily increased over the last three decades (p<0.001).1819
A group at the University of Michigan, Ann Arbor, has found dramatic variability in the age of first cataract surgery in different communities throughout the United States.
The group reviewed health-care claims data from a nationwide managed-care network to identify all enrollees age >40 who underwent one or more cataract surgeries between 2001 and 2011, recording the age of first cataract surgery and comparing the median age of first cataract surgery in 306 different communities throughout the United States.
Of the 1,052,277 enrollees diagnosed with cataracts, 243,467 (23.1 percent) underwent ≥1 cataract surgery. Large differences were noted in the median age of first cataract surgery among the different communities: those with the lowest median age of first cataract surgery (Lansing, Mich.—59.9 years, and Aurora, Ill.—60.1 years) differed considerably from those with the highest median age (Marquette, Mich.—77 years, Rochester, N.Y.—78.4 years and Binghamton, N.Y.—79.6 years). Differences in the age-standardized rates of cataract surgery varied fivefold across communities, ranging from 7.5 percent in Honolulu to 37.3 percent in Lake Charles, La. Some communities exhibited variability in age of first cataract surgery of as little as six to seven years (Lawton, Okla.—6.4 years and Yakima, Wash.—7.2 years) while others had large variability in the age of first cataract surgery (Bloomington, Ill.—12.7 years and Santa Cruz, Calif.—12.7 years).
The authors recommend that efforts be directed at understanding the extent to which these differences are due to patient-related factors, the supply of ophthalmologists or optometrists in a given community, and the impact of the timing of cataract surgery on patient outcomes.4384
Canadian researchers make an economic case for same-day bilateral cataract surgery as a cost-effective procedure and suggest that population and practice trends may make the need for it greater as time goes on.
Cost-effectiveness of cataract surgery will become increasingly important, they say. More than 2.5 million Canadians are currently suffering from cataract and this is likely to double by 2031. They project an increasing senior population to make up 23 percent of the population of Canada by 2031, with a resulting increase in cataract surgeries performed per year. Moreover, one in three Canadian ophthalmologists are over the age of 55 and are due to retire in the next decade; it is expected that the ratio of ophthalmologists to people over 65 will drop about 43 percent over the next 15 years.
They compared immediately sequential bilateral cataract surgery (ISBCS) and delayed sequential bilateral cataract surgery (DSBCS) using an analytic model based on data consisting of the cost of the surgery, intravitreal injections, medications and drops. The effectiveness was measured by the utility values associated with visual acuity in the better seeing eye.
The mean discounted cost (all figures in Canadian dollars) of ISBCS was $1,335 and of DSBCS was $1,783. The difference between the two cataract surgeries, ISBCS and DSBCS, equaled a 0.08 net utility gain. The cost-effectiveness of ISBCS was calculated to be $1,391 per QALY gained per patient treated. A 3 percent annual discount rate was used, resulting in 0.96 discounted QALYs gained over a 12-year life expectancy.4397
A study in Portland, Ore., assessed the impact of electronic health record systems versus paper on operating room workflow and documentation time during cataract surgery at an ophthalmic ambulatory surgery center.
For one month prior to and 10 months following EHR implementation at the Oregon Health & Science University ASC, a trained observer recorded cataract surgery duration, intraoperative documentation time, operating room turnover time and number of nursing staff.
Mean cataract surgery duration was 16.7 minutes (SD=11.4). Mean paper-based intraoperative documentation time was 6.8 (SD=1.2) minutes per surgery. During the initial two weeks after EHR implementation, intraoperative documentation time increased to 17.1 (SD=4.3) minutes (p<.0001), then decreased to 7.9 (SD=2.3) minutes by six to 10 months after EHR implementation, although this remained greater than paper documentation time (p<.05). There was no statistically significant difference between mean operating room turnover time with paper records (14.4 minutes) and mean turnover time two weeks or six to 10 months after EHR implementation (12.9 and 12.8 minutes, respectively). Only one nurse was needed per cataract surgery to complete both clinical care and documentation while using paper records, compared to a mean of 1.8 nurses while using EHRs.
EHR implementation for cataract surgery operative care was associated with increased intraoperative documentation time, but no significant change in operating room turnover time. Initially after EHR implementation, mean intraoperative documentation time more than doubled and was greater than mean surgery duration. Although EHR documentation time decreased over subsequent months, this was in the setting of increased nursing staff requirements.4414
Primary IOL implantation in children under 2 does not appear to confer any visual benefit in the first postoperative year, say British researchers. Nor does it alter the high risk of aphakic/pseudophakic glaucoma, but often commits children to early re-operation requiring repeat general anesthetic during the crucial neurological developmental period.
The IOLunder2 study, a prospective observational cohort study undertaken through the British Isles Congenital Cataract Interest Group, assesses outcomes following surgery with and without primary intraocular lens implantation in children less than 2 years old.
The group has collected one year postoperative outcomes data available on 221 children (131 bilateral cataract, 90 unilateral cataract). Ocular comorbidity was common: persistent fetal vasculature in 47 percent UC, 8 percent BC; axial length <16 mm in 23 percent BC, 8 percent UC; horizontal corneal diameter <9.5 mm in 10 percent BC, 3 percent UC. 56/131 BC and 48/90 UC children had primary IOL implantation. Implantation was more common in more socioeconomically deprived children (49 percent vs. 31 percent, p=0.01). The outcomes at one year after surgery included:
• Vision in normal range for age in 31 percent of all children with BC and 22 percent in all operated UC eyes, and also in normal range in 49 percent of BC children and 31 percent UC eyes without ocular comorbidity or cerebral visual impairment.
• Additional surgery for visual axis opacity (VAO) in 24 percent of all BC & 50 percent of all UC eyes.
• Postoperative glaucoma in 10 percent of all BC, and 9 percent of all UC eyes; additionally, ocular hypertension in 6 percent BC, 16 percent UC; 47 percent of pseudophakic BC eyes and 47 percent of UC eyes achieved early refraction within 1 D of planned outcome. Primary IOL was not independently associated with either visual outcome or postoperative glaucoma, but was associated with VAO (OR: 6.7 p=0.006 in BC, OR: 6.2 p<0.05 in UC ), where VAO was more likely with single-piece IOLs (OR 43.7 p<0.01).
The group plans further follow-up of the IOLunder2 cohort to provide currently unavailable data on predictors of favorable and adverse long-term outcomes.5672 REVIEW
Dr. Blecher is the co-director of Cataract and Primary Eye Care at the Wills Eye Institute, and the founding chief medical editor of the Review.
