Albert C. Neumann

Small incisions to control astigmatism during cataract surgery

ABSTRACT Astigmatic changes in three series of cataract surgical procedures were compared. Two series comprised eyes having phacoennilsification and implantation of a foldable silicone lens through a 3.0 mm to 4.0 mm incision or a 5.8 mm diameter polyinethylmethacrylate (PMMA) lens through a 6.0 min incision. The third series comprised eyes having a planned extracapsular cataract extraction (ECCE) procedure through a 10.0 min incision and implantation of a PIMA 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.

Efficacy of diclofenac sodium ophthalmic solution versus placebo in reducing inflammation following cataract extraction and posterior chamber lens implantation

Abstract One hundred forty‐eight patients were enrolled in a randomized, prospective, placebo‐controlled clinical trial evaluating the efficacy of diclofenac sodium (Voltaren Ophthalmic®) in reducing ocular inflammation following extracapsular cataract extraction with posterior chamber intraocular lens implantation. Eligible patients were enrolled and randomized (2:1 diclofenac:placebo) if the sum of anterior chamber cells plus flare one day postoperatively (baseline) was at least four. None of the patients received concomitant steroidal anti‐inflammatory treatment. The 99 patients receiving diclofenac sodium had significantly greater improvement from baseline in summed flare plus cell score than the 49 placebo patients at two to five days and seven to nine days after baseline. Similarly, diclofenac sodium patients had significantly less post‐baseline conjunctival erythema and ciliary flush than placebo patients. Significantly more diclofenac sodium patients than placebo patients showed moderate to marked improvement from baseline in overall assessment of inflammatory response. Forty‐nine percent of placebo patients but only 17% of diclofenac patients were considered therapeutic failures (P < .001). By five to seven days, 82% of diclofenac sodium patients and 59% of placebo patients had corrected visual acuities of 20/40 or better (P < .001). There were no clinically important differences in mean intraocular pressure at any visit.

Hyperopic thermokeratoplasty: Clinical evaluation

ABSTRACT A new procedure, hyperopic thermokeratoplasty (HTK), developed in the Soviet Union for the correction of hyperopia, uses controlled thermal burns of the corneal stroma with a retractable probe tip preset to penetrate the cornea at 95% depth. The coagulations are applied in a radial pattern for spherical hyperopia. Only the peripheral cornea is treated and the effect is titrated by varying the optical zone and number of rays. The thermal effect flattens the peripheral cornea and steepens the central cornea. In this report, we prospectively evaluated the refractive results of a group of 61 HTK patients. Mean preoperative spherical equivalent was 3.9 diopters (D). Mean follow‐up to date is 5.2 months, with 44% of cases evaluated at six months and 31% at one year. The initial effect of surgery (at one day) was a mean decrease in hyperopia of 6.0 D (standard error of the mean [S.E.] = 0.3 D), resulting in a mean spherical equivalent of −2.1 D (S.E. = 0.2 D). There was a steep regression of effect between one clay and two months at which point average refraction was close to emmetropia. After two months, there was a gradual but continuing regression of effect, leveling off after six months. At five to six months, 63% of cases were undercorrected by at least a diopter; at 9 to 12 months, 83% of cases were undercorrected. The overall change in spherical equivalent at each time increased as optical zone size decreased. Adjustments to the surgical prediction software (developed in the Soviet Union) to render it more suitable for U.S. eyes are underway; smaller optical zones and/or more rays will be used to obtain final stable refractive results closer to emmetropia.

Radial keratotomy: A comprehensive evaluation

A prospective clinical investigation of radial keratotomy employing the Fyodorov method and instrumentation was initiated in March, 1980. The results of the first 147 eyes undergoing this surgical procedure for the reduction or elimination of myopia were analyzed one year following surgery. The mean preoperative, uncorrected visual acuity was finger counting vision and the mean preoperative myopic spherical equivalent was 5.33 diopters. The preoperative myopic refractive error ranged from 1.75 to 11.75 diopters.Radial keratotomy resulted in a mean uncorrected visual acuity of 20/35 with a mean reduction on myopia of 4.66 diopters. Eighty percent of the 147 eyes experienced 20/40 or better uncorrected vision. Sixty-eight percent of high myopia eyes (6.00 to 11.75 D) attained this level of uncorrected vision with a mean reduction of myopia of 6.23 diopters.Glare and variation of vision were the most frequently reported complications. A non-progressive endothelial cell loss of 5.2 percent was observed. The degree of preexisting myopia, patient age, fellow eye experience and surgeon learning curve significantly influenced the surgical result and facilitated the predictability of the procedure. Incision-depth was directly related to surgical result. The low myopia group achieved stabilization of effect by six months while stabilization occurred later in patients with high degrees of initial myopia. Patient satisfaction was high and 78 per cent of the patients elected to undergo radial keratotomy in their fellow eye.

Glare disability devices for cataractous eyes: a consumer's guide

ABSTRACT We evaluated five commercially available glare testers to determine how accurately each device predicted outdoor Snellen acuity in cataract patients. Predicted outdoor Snellen acuity was compared to actual Snellen outdoor acuity for the Miller‐Nadler glare tester, the brightness acuity tester (BAT), the InnoMed true vision analyzer (TVA), the VisTech VCT 8000, and the EyeCon 5. All five devices were evaluated in a single series of eyes. We ranked the five glare testers as follows based upon their ability to predict outdoor Snellen acuity within one Snellen line: (1) BAT (73%), (2) TVA (69%), (3) VisTech VCT 8000 (56%), (4) Miller‐Nadler (47%), and (5) EyeCon 5 (15%). All five devices were also evaluated for their capacity to provide false negative or false positive results and for testing time per eye, test difficulty level for the patient, versatility, upgrading capacity, examining room adaptability, and price. We concluded that glare testing of cataract patients is necessary to measure visual disability and that glare testing devices vary in their ability to predict outdoor vision.

Radial Thermokeratoplasty for the Correction of Hyperopia

Hyperopic thermokeratoplasty involves making controlled thermal burns in the corneal stroma in a radial pattern up to a premarked clear zone. It steepens the central cornea and reduces the hyperopia. A series of 117 radial thermokeratoplasty eyes done in the Soviet Union were analyzed. Mean preoperative hyperopia of +5.27 diopters (range = +0.50 to +17.00 D) was reduced at 12 months after surgery by a mean of -3.48 D, resulting in a mean postoperative spherical equivalent of +1.84 D. Average correction was 70.8%. Forty percent of eyes were corrected to less than 1.00 D residual refractive error; however, 58% were undercorrected by 1.00 D or more. The proportion of eyes seeing 20/40 or better unaided increased from 10% preoperatively to 52% by 3 months after surgery and remained at 53% at 12 months after surgery. Overall refractive stability was demonstrated during the 1st postoperative year. Stepwise regression showed that none of the preoperative or surgical factors significantly predicted outcome when all eyes were evaluated.

Complications associated with STAAR silicone implants

ABSTRACT We compared the incidence of various complications in consecutive series of cases in which 76 eyes received STAAR silicone intraocular implants and 76 eyes received small incision IOLAB G708G polymethylmethacrylate (PMMA) intraocular implants. All surgeries were performed by the same surgeon employing the same phacoemulsification technique. A higher incidence of lens subluxation, lens repositioning, corneal edema, and elevated intraocular pressure was observed in the eyes receiving STAAR silicone implants than in the eyes receiving IOLAB PMMA implants, In addition, a YAG laser posterior capsulotomy could not be performed through several STAAR silicone RMX 1 model implants. An invasive pars plana posterior capsulotomy was necessary in these eyes. We also found that the STAAR silicone RMX 3 model implants were often pitted by the YAG laser during successful posterior capsulotomies. Despite these problems, the STAAR silicone intraocular lens group achieved corrected vision similar to the PMMA lens group.

Advantages and limitations of current soft intraocular lenses

ABSTRACT We report our clinical experience with six soft intraocular lenses: (1) STAAB silicone, (2) CooperVision/Schlegel silicone, (3) IOLAB silicone, (4) Allergan Medical Optics (AMO) silicone, (5) Fyodorov silicone, and (6) Alcon hydrogel (IOGEL). We found that these soft intraocular lenses have several common design problems. The singlesize design of five of the six soft lenses can lead to a windshield‐wiper decentration effect in lenses too small for larger eyes. We observed several instances in which the one‐piece lenses became decentered, subluxed, and vaulted anteriorly against the iris or posteriorly away from the iris as postoperative capsulozonular changes occurred. We found that the insertion methods for these soft lenses need refining to reduce the risk of intraocular damage and wound stretching if the lenses are to be folded and inserted through a small 3.0 mm to 3.5 mm incision. The surface and physical characteristics of these lenses may also require further study. We observed folding grooves, sebacium deposits, and rust from the insertion instrument on some lenses inside the postoperative eye and pigment dispersion associated with hydrogel lenses. We conclude that small diameter polymethylmethacrylate implants are the best choice for small incision cataract surgery at this time.

Hexagonal keratotomy for correction of low hyperopia: Preliminary results of a prospective study

ABSTRACT Fifteen sighted eyes of 11 patients had hexagonal keratotomy for the correction of low hyperopia. Mean preoperative hyperopia of +3.21 diopters (range +1.75 to +5.50) was reduced a mean of 2.16 diopters (range 0 to −3.25) and keratometry was increased a mean of +2.22 diopters (range +0.75 to +3.71). Follow‐up averaged 9.5 months (range 2.0 to 17.5). Ten of the 15 eyes (67%) had at least six months follow‐up. No eye had better than 20/80 uncorrected visual acuity preoperatively. Fourteen eyes (93%) had 20/80 or better uncorrected acuity at the most recent postoperative visit. Nine of the 15 eyes (60%) had uncorrected acuity of 20/40 or better. Refractive spherical equivalent appeared to stabilize by three months for most patients. Astigmatism was increased a mean of only +0.02 diopter and no serious complications occurred. Further follow‐up is required to assess the safety and efficacy of hexagonal keratotomy for reducing low levels of hyperopia.

Refractive evaluation of astigmatic keratotomy procedures

ABSTRACT 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 eves.