Biomedical subjects

M G Raanan

Publications and source records attributed to M G Raanan.

At least 19 recordsLinked to original sources

PubMed1999

Piggybacking intraocular implants to correct pseudophakic refractive error.

OBJECTIVE: To determine the safety and efficacy of implanting a second intraocular lens (IOL) to correct pseudophakic refractive error. DESIGN: Noncomparative, prospective, consecutive case series. PARTICIPANTS: Eight eyes of eight normal pseudophakes and seven eyes of seven postpenetrating keratoplasty (PK) pseudophakes were included in the study. INTERVENTION: A second intraocular lens (IOL) was implanted anterior to the first in each eye in the study. MAIN OUTCOME MEASURES: Efficacy was determined based on the achieved refractive correction and Snellen uncorrected visual acuity measurements. Safety was determined based on loss of best-corrected visual acuity and operative and postoperative complications. RESULTS: Before surgery, spherical equivalents ranged from -5.12 diopters (D) to 7.5 D, with a mean absolute deviation from emmetropia of 3.38 D (1.62). After surgery, spherical equivalents ranged from -2.75 D to 0.5 D, with a mean absolute deviation from emmetropia of 1.21 D (0.90). Before surgery, only 7% of patients had 20/40 or better uncorrected vision, whereas after surgery, 50% had that level of vision. CONCLUSIONS: Implanting a second IOL is a viable option for correcting pseudophakic refractive error.

Humans↗

PubMed1998

Safety and efficacy of intracameral injections of unpreserved lidocaine to reduce intraocular sensation.

PURPOSE: To determine the safety and efficacy of intracameral injections of unpreserved lidocaine to reduce intraocular sensation. SETTING: Carolina Eye Associates, Southern Pines, North Carolina, USA. METHODS: In this prospective study, 100 patients having phacoemulsification under topical anesthesia were randomly assigned to receive an intracameral injection of unpreserved lidocaine (0.5 cc of a 1% unpreserved solution) or balanced salt solution. RESULTS: Ninety-three patients completed the study. There were no significant between-group differences in cell density parameters or Kowa laser flare-cell meter measurements. Seventy-eight percent of lidocaine patients and 56% of controls reported no sensation (P = .048, Fisher's exact test). CONCLUSION: Intracameral injections of unpreserved lidocaine safely and effectively reduced intraocular sensation during phacoemulsification.

Anesthesia, Local↗

PubMed1997

Corneal thickness variation during eight-incision radial keratotomy.

PURPOSE: To determine the degree of corneal thickness variability that may be encountered during routine radial keratotomy (RK) surgery. SETTING: Office refractive surgical suite. Laurel Eye Clinic, Brookville, Pennsylvania. METHODS: This study statistically analyzed variability in corneal thickness measured at the optical zone in 140 consecutive eight-incision RK cases. Pachymetry measurements were assessed at each of the eight circumferential optical zone locations and then evaluated in regard to intra-patient variation by location and inter-patient variation in location thickness patterns. Covariants such as central corneal thickness and differing optical zone size were also analyzed. RESULTS: Mean corneal thickness (adjusted for optical zone and central thickness) between the three superior locations and the three inferior locations varied by 10 microns. In more than 10% of cases, this adjusted difference was greater than 30 microns. Central corneal thickness and differing optical zone sizes had a significant effect on the results. CONCLUSION: Corneal thickness measured at the optical zone during eight-incision RK varied significantly by incision location, bringing into question the notion that one blade depth setting is adequate for all incisions.

Cornea↗

PubMed1997

Unpreserved lidocaine to control discomfort during cataract surgery using topical anesthesia.

PURPOSE: To determine whether intraoperative unpreserved lidocaine further decrease discomfort or pain during sutureless small incision cataract surgery and intraocular lens (IOL) implantation under topical anesthesia. SETTING: Outpatient ambulatory surgical center. METHODS: In this prospective controlled study, comparable eligible patients were randomized to receive 0.1 cc unpreserved lidocaine 1% or 0.1 cc balanced salt solution (BSS) (control group) in double-masked fashion. Study drugs were injected intracamerally 1 minute before phacoemulsification. A predefined uniform pain/discomfort scale was used for assessment during phacoemulsification and IOL insertion. A secondary study using a 0.5 cc dose was also performed. RESULTS: Twenty-six percent in the control group and 9% in the lidocaine group had discomfort pain scores of 2 or more; 10% in the BSS group felt increased pressure or pain during phacoemulsification. In the lidocaine group, discomfort was felt mainly during IOL insertion, possibly as a result of wound manipulation. During phacoemulsification, no patient in the lidocaine group reported pain; 2% felt increased pressure during phacoemulsification. A dose increase to 0.5 cc reduced any intraocular sensation to 3% in the lidocaine group. No patient in either group had significant cell loss or adverse events. CONCLUSION: Intraoperative lidocaine is safe and effective in controlling intraoperative discomfort.

Aged↗

PubMed1994

Long-term (5- to 12-year) follow-up of metal-blade radial keratotomy procedures.

OBJECTIVE: To evaluate the long-term stability of the refractive outcome after metal-blade radial keratotomy procedures. DESIGN: A cohort of 146 patients who underwent 225 consecutive metal-blade radial keratotomy procedures that were performed under a uniform protocol between November 1979 and August 1981 was monitored prospectively, with 64% of the patients followed up for at least 5 years. MAIN OUTCOME MEASURES: Changes in spherical equivalent and changes in average keratometry were evaluated within the following periods: 3 months to 1 year; 1 to 2 years; 2 to between 3 and 4 years (mean, 3.7 years); between 3 and 4 (mean, 3.7 years) to between 5 and 12 years (mean, 8.5 years); and 1 to between 5 and 12 years (mean, 8.5 years). RESULTS: Total mean change in refraction between 1 year and the average of 8.5 years of follow-up was 1.01 diopters (D) (SD, 1.13 D). At 1 year, 31% of the cases were at least 1 D hyperopic, whereas at an average of 8.5 years, 48% were at least 1 D hyperopic. Fifty-four percent of the cases had shifted in the hyperopic direction by 1 D or more. Stepwise regression analysis failed to identify significant predictive factors for the hyperopic shifts. CONCLUSIONS: The trend toward progressive hyperopic shifts within this cohort has continued with time. Other long-term studies have documented similar, although somewhat smaller, hyperopic shifts among both patients treated with metal-blade and patients treated with diamond-blade procedures. Causative factors for the hyperopic shift have not been identified. It remains to be seen if eyes undergoing current, more cautious surgical approaches to radial keratotomy will also experience this phenomenon.

Follow-Up Studies↗

PubMed1994

Small incision surgery with the STAAR Elastimide three-piece posterior chamber intraocular lens.

One hundred twelve patients scheduled for uncomplicated cataract removal were randomly assigned to receive a STAAR Elastimide three-piece foldable intraocular lens inserted through a 4.0 mm incision or a STAAR poly(methyl methacrylate) (PMMA) lens inserted through a 7.0 mm incision. The same surgeon performed all surgeries using identical techniques, except for incision size and number of sutures. Patients receiving Elastimide lenses had significantly better uncorrected visual acuity postoperatively than patients receiving PMMA lenses and also had significantly less keratometric cylinder, surgically induced cylinder (vector method), and refractive cylinder. The Elastimide foldable lens offers the advantages of small incision surgery for patients who require a three-piece lens.

Aged↗

PubMed1992

Effect of posterior chamber intraocular lens design and surgical placement on postoperative outcome.

Intraocular lens (IOL) design, optical configuration, and placement have potential effects on postoperative outcome. Laboratory studies have suggested that one-piece, biconvex designs may reduce or delay posterior capsular opacification and that in-the-bag fixation of the posterior chamber IOL may reduce inflammation. To document the clinical significance of IOL design and placement, we conducted a randomized, prospective, clinical trial. Six hundred uncomplicated capsulorhexis and phacoemulsification patients were randomized in a three-factor design to receive an IOL that was one-piece or three-piece, had a biconvex, plano-convex, or laser ridge optic, and was bag-or sulcus-fixated. Treatment differences were related to lens placement. Patients with bag-fixated IOLs had less posterior capsular opacification, fewer YAG laser capsulotomies, a higher percentage of centered lenses, less inflammation, and fewer late posterior capsular striae than those with sulcus-fixated IOLs. In the latter group, patients with three-piece IOLs had fewer posterior capsular striae at three months postoperatively. All six occurrences of haptic loop distortion were in patients with three-piece IOLs. Patients with the one-piece design had less late inflammation than those with the three-piece design. Fewer YAG capsulotomies were necessary at one year in patients with the biconvex design than in those with the plano-convex or laser ridge configurations. Operative complications, endothelial cell loss, and postoperative complications were not IOL-related.

Adult↗

PubMed1992

Effect of a superficial and a deep scleral pocket incision on the incidence of hyphema.

Deep tunnel scleral pocket incisions were developed to control surgically induced astigmatism following cataract and intraocular lens implantation surgery. A more superficial, shallow scleral pocket incision was developed to reduce the rate of postoperative hyphema. To test its effectiveness, a randomized prospective clinical study was performed. One hundred twenty-nine eyes of 129 patients were randomized: 66 to receive a deep tunnel pocket and 63 to receive the superficial pocket. In both groups the incision was made 3 mm posterior to the limbus. For the deep pocket cases, a blade setting of 0.27 mm was used and the wound was dissected forward toward the entry site, creating a long, deep, narrow tunnel. For the superficial wound cases, a 0.17 mm blade setting was used and the entire wound was dissected to the edge of the anatomic limbus, creating a thin scleral flap. The left side was then fanned out toward the left with the entry site slightly into clear cornea. At one day after surgery, 22 cases (34%) in the deep pocket group and four cases (6%) in the superficial pocket group had hyphemas. The difference in hyphema rates was statistically significant (P less than .001).

Adult↗

PubMed1992

Effect of suture material on postoperative astigmatism.

Two hundred patients were enrolled in a randomized, prospective clinical trial comparing the use of 10-0 nylon, 10-0 polypropylene (Prolene), 11-0 polyester (Mersilene), and 10-0 polyethylene (Novafil) suture materials on the amount and decay curves of surgically induced astigmatism following intraocular lens (IOL) surgery. Patients with Mersilene and nylon sutures had the highest amounts of induced with-the-rule (WTR) cylinder (significantly more than Prolene) at one day after surgery. However, the WTR cylinder decayed rapidly for nylon during the first three months but more slowly for Mersilene because of its lack of stretchability. The Prolene group had the lowest level of induced WTR cylinder at one day, but against-the-rule (ATR) drift occurred, leaving cases with ATR astigmatism by a year. The nylon group had the second highest amount of induced WTR cylinder at one day, which had decayed to ATR cylinder by five months. Between one and two years postoperatively, the nylon group experienced a significant ATR shift. The amount of early induced WTR cylinder seemed to be related to the knot-tying technique and tissue gripping characteristics, whereas the shape of the decay curve was related to the material characteristics of the suture.

Adult↗

PubMed1991

Visual and refractive results of multifocal intraocular lenses.

One hundred forty-nine selected patients with bilateral multifocal intraocular lenses (IOLs) were evaluated and compared retrospectively with 131 patients with bilateral monofocal IOLs. Seventy-eight percent of multifocal cases and 74.8% of monofocal cases had uncorrected visual acuity of 20/40 or better. Fifty-four percent of multifocal cases had near uncorrected visions of J1 to J3. Eighteen percent had best-corrected near vision of J4 or worse. Sixty-three percent of multifocal cases versus 4% of monofocal cases needed no spectacle correction. Multifocal cases reported significantly more visual side effects (flare, glare, and halos). The 10% of cases with poor satisfaction (rating vision as fair-to-poor) had significantly (P = 0.03) more postoperative astigmatism (1.1 prism diopters [D] versus 0.74 D) compared with satisfied (good-to-excellent) cases. Patients who were dissatisfied reported more need for corrective lenses but not more side effects. A greater decrease in contrast sensitivity at low contrast levels was detected among multifocal cases. Both groups had similar contrast sensitivity at 96% and 50% contrast, but at 11% contrast, multifocal cases averaged a loss of 3.45 Snellen lines (to 20/48.2) compared with 2.65 lines (to 20/36) for monofocal cases.

Consumer Behavior↗

PubMed1990

Inhibition of blood-aqueous humor barrier breakdown with diclofenac. A fluorophotometric study.

Various doses of a new topical nonsteroidal anti-inflammatory agent, diclofenac sodium, were tested against prednisolone sodium phosphate in a randomized double-masked study to determine comparative efficacy and safety regarding the reduction of postsurgical ocular inflammation. Inflammation was assessed by measuring fluorescein leakage into the anterior chamber using fluorophotometry techniques. Increased leakage in each patient's operated-on eye compared with the unoperated-on control eye was attributed to a breakdown in the blood-aqueous barrier caused by the cataract surgery. Elimination or significant reduction of fluorescein leakage within a treatment group constituted increased efficacy in controlling inflammation. A total of 124 cases were analyzed. There were no preoperative differences among groups in fluorescein leakage. At 1 week after surgery, all three diclofenac groups had significantly less fluorescein leakage compared with the prednisolone group. Mean percent increases were 56% to 118% in diclofenac groups vs 324% in the prednisolone group. No differences among diclofenac concentrations were detected. The differences between prednisolone and diclofenac were also present, although of lesser magnitude, at 3 weeks. This demonstration of increased efficacy of the nonsteroidal anti-inflammatory agent vs prednisolone is promising given the known side effects of ocular steroids.

Aged↗

PubMed1990

Effect of sulcus vs capsular fixation on YAG-induced pressure rises following posterior capsulotomy.

Neodymium-YAG capsulotomy for secondary cataracts can induce acute intraocular pressure rises, possibly by a blocking of the trabecular meshwork by debris. To test a hypothesis that bag-fixated intraocular lenses may act as a barrier to debris, thus reducing pressure rises after YAG capsulotomy, we conducted a study comparing pressures (at 1, 2, 3, 6, and 24 hours after YAG capsulotomy) between bag-fixated and sulcus-fixated cases. There were substantial and statistically significant intraocular pressure rises in the sulcus-fixated group starting at 1 and 2 hours after YAG capsulotomy, and peaking at 3 hours (mean rise, 7.83 mm Hg). There were no such peaks of intraocular pressure rise among bag-fixated cases (mean change, -0.32 mm Hg at 3 hours). There was a weak but significant (r = -.18) correlation between the change 1 hour after YAG capsulotomy in intraocular pressure and percent of enclosure of the intraocular lens optic among bag-fixated cases. Higher proportions (fourfold to fivefold) of cases with sulcus-fixated lenses had significant flare and particulate matter in the anterior chamber, compared with bag-fixated cases.

Adolescent↗

PubMed1990

Comparison of the SRK/T formula and other theoretical and regression formulas.

We compared the predictive accuracy of the SRK/T formula to the SRK II, Binkhorst II, Hoffer, and Holladay formulas in seven series of cases totaling 1,050 eyes. In the combined group, the SRK/T and Holladay formulas performed only slightly better than the other formulas. In short eyes (less than 22 mm), all formulas performed well, with the SRK/T, SRK II, and Holladay formulas performing marginally better. In moderately long eyes (greater than 24.5 mm, less than or equal to 27 mm), the Hoffer and Binkhorst II formulas had a greater proportion of cases with greater than 2 diopters (D) of error and the SRK/T and Holladay were again marginally better. In the very long eyes (greater than 27 mm and less than or equal to 28.4 mm), there were only 11 cases and all formulas performed well since none had greater than 2 D of prediction error. In an extremely long eye data set (greater than 28.4 mm), the SRK II formula clearly gave the poorest result. Eyes of this length occurred in only 0.1% of cases in our unselected series. Results support the contention that the present second and third generation IOL power formulas give fairly equivalent accuracy. Other factors, such as availability, ease of use, and ability to tailor or individualize, become major considerations.

Eye↗

PubMed1990

Effect of thermokeratoplasty on corneal curvature.

A cadaver eye model was used to evaluate and quantify the use of thermokeratoplasty for steepening the central cornea to correct hyperopia. Four groups of eye-bank eyes were treated with four separate surgical plans. Each plan involved the placement of controlled thermal burns (in the depths of the corneal stroma, using a cautery probe) applied in a radial pattern up to a premarked optical zone. The plans differed in the sequence of surgical steps. All plans progressively added radials and applications (to decrease optical zone) in various sequences. Corneal curvature was measured at baseline and at each surgical step. As more surgery was done within each plan, the corneas became progressively steeper. Total mean changes in corneal curvature ranged from 16.26 diopters to 19.76 diopters, depending on the plan. At each optical zone, as the number of radials increased, the effect increased. With progressively smaller optical zone size, the effect also increased.

Cornea↗

PubMed1989

Refractive evaluation of astigmatic keratotomy procedures.

We evaluated the efficacy of three transverse incision astigmatic keratotomy procedures using a vector analysis that enabled us to determine the magnitude of the effect and the axis in which it occurred. These procedures were used for low levels of astigmatism (0.5 diopter [D] to 3.75 D): (1) staggered, radial-touching transverse (T) incisions, (2) non-radial-touching T incisions, and (3) T incisions with interrupted radial. Most procedures were performed in conjunction with radial keratotomy for spherical correction of myopia. The non-radial-touching T procedure was the least effective method of reducing astigmatism. The staggered, radial-touching T and T with interrupted radial procedures were equally effective in reducing over 93% (on the average) of the preoperative astigmatism. Of these two procedures, the T with interrupted radial procedure was the most accurate, with the effect of the surgery deviating less than ten degrees from the desired axis in over 70% of the eyes.

Adult↗

PubMed1989

Small incisions to control astigmatism during cataract surgery.

Astigmatic changes in three series of cataract surgical procedures were compared. Two series comprised eyes having phacoemulsification and implantation of a foldable silicone lens through a 3.0 mm to 4.0 mm incision or a 5.8 mm diameter polymethylmethacrylate (PMMA) lens through a 6.0 mm incision. The third series comprised eyes having a planned extracapsular cataract extraction (ECCE) procedure through a 10.0 mm incision and implantation of a PMMA posterior chamber lens. Surgically induced cylinder changes were compared by examining preoperative and postoperative dioptric cylinder power changes without regard to axis changes and by using vector analysis to compute induced cylinder for cases with axis changes. Both phacoemulsification series had similar mean induced cylinder levels, which were significantly less than mean induced cylinder in the ECCE group at both three and six months after surgery. Over 70% of the eyes in the two small incision phacoemulsification groups achieved an uncorrected visual acuity of 20/40 or better at three months, whereas only 28% of the ECCE group achieved that acuity. We concluded that the phacoemulsification procedure induced significantly less astigmatism and provided faster visual rehabilitation than the ECCE procedure. Furthermore, the use of small diameter PMMA IOLs inserted through small incisions minimized surgically induced cylinder in a way comparable to the use of foldable silicone implants, while maintaining good visual results with fewer postoperative complications.

Adult↗

PubMed1988

The relationship between indoor and outdoor Snellen visual acuity in cataract patients.

One hundred six cataractous eyes of 78 patients were evaluated to examine the relationship between indoor and outdoor Snellen visual acuity. While 81 of all cataractous eyes (76.4%) had Snellen visual acuities of 20/40 or better when tested indoors, only 33 eyes (31.2%) had 20/40 or better Snellen visual acuities when tested outdoors facing the sun. When tested indoors, only three eyes (2.8%) had Snellen visual acuities worse than 20/80, while 31 eyes (29.2%) had outdoor Snellen visual acuities worse than 20/80. Ten eyes (9.4%) had outdoor Snellen visual acuities worse than 20/200. Seventy-four eyes (69.8%) had outdoor visual acuities that were at least two Snellen lines worse than those measured indoors and 23 eyes (21.7%) had outdoor visual acuities that were at least five Snellen lines worse. The median difference between indoor and outdoor visual acuity was three Snellen lines. The need for increased precision in the ability to assess outdoor "real world" vision while in the ophthalmologist's examination room is discussed. Clearly, indoor Snellen visual acuity alone is insufficient to evaluate functional visual impairment in cataract patients.

Cataract↗

PubMed1988

The relationship between cataract type and glare disability as measured by the Miller-Nadler glare tester.

Cataract patients were tested for glare disability using the Miller-Nadler glare tester. Predicted outdoor visual acuity was then compared with the actual outdoor visual acuity. The Miller-Nadler glare test scores predicted actual outdoor visual impairment to within one Snellen line in 46.7% of the eyes, underestimated actual outdoor visual impairment by more than one Snellen line in 31.5% of the eyes, and overestimated outdoor visual impairment by more than one Snellen line in 21.7% of the eyes. Overall, 64.1% of the eyes had outdoor vision which was more closely predicted by their glare scores than by their indoor Snellen acuity. When the cataractous eyes were divided into three categories, eyes with pure nuclear sclerosis, eyes with nuclear sclerosis and posterior subcapsular opacities, and eyes with all other cataractous combinations, predictability differences were observed. Although we found that actual outdoor visual acuities were not precisely predicted by disability glare scores in a substantial proportion of our subjects, the glare scores were considerably more predictive than indoor Snellen acuity. Further development and field testing of glare testing devices as predictors of outdoor visual impairment is necessary.

Cataract↗