Roberto Bellucci

Visual acuity and contrast sensitivity comparison between Tecnis and AcrySof SA60AT intraocular lenses: A multicenter randomized study

Purpose: To evaluate best corrected visual acuity (BCVA) and photopic and mesopic contrast sensitivity in pseudophakic patients implanted either with the aspheric intraocular lens (IOL) designed to correct for corneal spherical aberration or with a conventional IOL. Setting: Three surgical centers participated this prospective randomized masked comparative study. Methods: Thirty eyes of 30 patients after aspheric lens implantation (Pfizer/Pharmacia Tecnis Z9000) were compared with 30 eyes of 30 age‐matched patients after conventional lens implantation (Alcon AcrySof SA60AT). Two to three months after surgery, best spectacle corrected distance visual acuity was measured using the Early Treatment Diabetic Retinopathy Study chart. Contrast sensitivity was measured by sinusoidal grating charts for distance at photopic (85 cd/m2) and mesopic (6 cd/m2) luminance level with optical correction in place. Tested spatial frequencies were 1.5, 3, 6, 12, and 18 cycles per degree (cpd). Results: The mean BCVA was −0.053 ± 0.044 logMAR in eyes with the aspheric Tecnis IOL and 0.006 ± 0.059 logMAR in eyes with the conventional AcrySof IOL (P = .0001). Eyes with the aspheric IOL showed better contrast sensitivity at spatial frequencies of 3 cpd (P<.05) and 6, 12, and 18 cpd (P<.01) in photopic and in mesopic conditions. Peak improvement occurred at 18 cpd and was 36% (0.29 log units) in photopic and 54% (0.27 log units) in mesopic conditions. Conclusions: The aspheric Tecnis IOL yielded better BCVA and better distance contrast sensitivity than the conventional IOL. The differences were clinically significant for higher spatial frequencies. The results give some suggestions for further studies.

Comparison of wavefront aberrations and optical quality of eyes implanted with five different intraocular lenses

PURPOSE We compared corneal and total higher order wavefront aberrations in 25 pseudophakic eyes implanted with five different types of intraocular lenses to obtain an objective evaluation of the optical quality of these pseudophakic eyes. Five IOLs per type were studied. METHODS Implanted lenses were the Pharmacia Tecnis Z9000 with negative spherical aberration, Pharmacia 911 Edge, Alcon Acrysof SA60AT and MA60BM, and Allergan Sensar AR40e. Eyes were examined using the Topcon KR-9000PW topographer/aberrometer, which obtains simultaneous coaxial measurements of corneal and ocular aberrations, and displays the calculated Point Spread Function (PSF) and Modulation Transfer Function (MTF). RESULTS Corneal spherical aberration was positive in all tested eyes. For a 4-mm optical zone, ocular spherical aberration was 0.0054+/-0.0172 microm root-mean-square (RMS) in eyes implanted with the Tecnis lens, and was 0.0562 to 0.0974 microm RMS in eyes implanted with the four other conventional IOLs. A myopic refractive shift with mydriasis of -0.08 D occurred with the Tecnis IOL; it was -0.57 to -0.90 D with the conventional IOLs. Coma did not show a substantial reduction with any of the IOLs. Total wavefront aberrations showed nonsignificant reduction with the Tecnis lens. The PSF and the MTF also showed nonsignificant improvements over conventional IOLs. CONCLUSIONS The optical quality of pseudophakic eyes can be measured in vivo by aberrometers. Different IOLs resulted in measurably different outcomes. In this preliminary study, compensation of the spherical aberration observed with the Tecnis lens confirmed the theoretical predictions associated with this lens and resulted in no myopic shift in refraction with mydriasis.

Secondary implantation of angle-supported anterior chamber and scleral-fixated posterior chamber intraocular lenses

Purpose: To compare the results of secondary implantation of angle‐supported anterior chamber intraocular lenses (IOLs) and scleral‐fixated posterior chamber lenses. Setting: Eye Clinic, University of Verona, Italy. Methods: This study of 68 eyes of 60 patients comprised two groups. In Group A (n = 35), an angle‐supported anterior chamber IOL was implanted and in Group B (n = 33), a scleral‐fixated posterior chamber IOL. Follow‐up was from 12 to 45 months. Results: In Group A, one eye developed a retinal detachment and another, pseudophakic bullous keratopathy. In Group B, one eye had a major intraoperative choroidal hemorrhage and two developed a retinal detachment postoperatively. All other complications were minor. Conclusion: Although the rate of sight‐threatening complications was about 6% for both groups, scleral‐fixated posterior chamber IOLs were associated with more intraoperative and postoperative complications than angle‐fixated anterior chamber IOLs, and surgery took longer. Thus, anterior chamber IOL implantation should be considered for older patients with relatively good endothelial cell counts.

Spherical aberration and coma with an aspherical and a spherical intraocular lens in normal age-matched eyes.

PURPOSE: To study optical aberrations in eyes having uneventful cataract surgery and in‐the‐bag implantation of an aspherical Tecnis Z9000 intraocular lens (IOL) (AMO) or a spherical CeeOn Edge 911 IOL (Pharmacia) and compare the results with those in a group of phakic age‐matched eyes. SETTING: Ophthalmic Unit, Hospital and University of Verona, Verona, Italy. MATERIALS: Three groups, each with 30 patients (30 eyes), were examined with the Topcon KR‐9000PW topographer/aberrometer. Spherical aberration and coma were analyzed in detail for 4.0 mm optical zone. Internal values were obtained by subtracting corneal aberrations from ocular aberrations. Point spread function and modulation transfer function (MTF) were considered for optical quality. RESULTS: The mean internal spherical aberration Z40 was −0.048 μm ± 0.017 (SD) in the Tecnis group, +0.033 ± 0.026 μm in the 911 Edge group (P<.001), and −0.013 ± 0.056 μm in the phakic group (P = .149). The mean internal vertical coma Z3−1 was 0.087 ± 0.056 μm, 0.054 ± 0.043 μm (P = .005), and 0.044 ± 0.044 μm (P<.001), respectively. The internal horizontal coma Z3+1 showed a similar pattern; however, total resulting coma was similar in the 3 groups. The mean Strehl ratio was 0.284 ± 0.166 in the Tecnis group, 0.145 ± 0.077 in the 911 Edge group (P<.01), and 0.164 ± 0.097 in the phakic group (P<.01). The MTF curve was better in the Tecnis group (P<.001). CONCLUSIONS: After uneventful implantation, the aspherical IOL yielded better ocular aberration and optical quality results than the spherical IOL. Induced coma was somewhat higher in the Tecnis group; however, the overall results were not affected. Physiologic IOL decentration after correct in‐the‐bag implantation did not negate the advantages of asphericity.

Clear lens phacoemulsification for correction of high myopia

Purpose: To assess phacoemulsification and posterior chamber intraocular lens (IOL) implantation as an effective, safe, and predictable technique for the correction of high myopia. Setting: University Eye Clinic of Verona, Verona, Italy. Methods: A series of 25 eyes with myopia higher than –12.0 diopters (D) had clear lens extraction by phacoemulsification and IOL implantation in the capsular bag. The mean postoperative follow‐up was 42.92 months ± 3.76 (SD). Results: No serious intraoperative complications occurred. Uncorrected visual acuity improved in all cases. The mean postoperative best corrected visual acuity improved by an average of 1 line. One case (4.0%) of postoperative retinal detachment (RD) occurred at 12 months. One case (4.0%) of biometric error (3.0 D) occurred. Conclusion: Clear lens extraction by phacoemulsification and IOL implantation in a series of highly myopic eyes was effective and had an acceptable predictability and a low rate of complications. Careful evaluation of the retinal periphery by indirect ophthalmoscopy is recommended to avoid postoperative RD.

Comparison of the effects of nine beta-adrenergic blocking agents on intraocular pressure in rabbits

The intraocular pressure lowering effects of nine beta-adrenergic receptor blocking agents were compared using two different models of experimental ocular hypertension in rabbits. All the nine drugs possess, to different extents, a clear pressure-lowering action after topical administration into the conjunctival sac. For potency and duration of action, the best results were obtained with timolol and sotalol. Pindolol, oxprenolol, practolol, and propranolol are also fairly potent, while less impressive effects were produced by atenolol, butidrine, and metoprolol. With the exception of propranolol, all the drugs were well tolerated by the ocular tissues.

Optimizing higher-order aberrations with intraocular lens technology.

Purpose of review Aspheric intraocular lens technology has been implemented during the past 5 years, and more and more intraocular lenses with different amounts of asphericity are becoming available. Despite the efficacy in the correction of spherical aberration and the good results on implanted eyes, the theoretical advantages of aspheric intraocular lenses are still controversial. Recent findings All investigations showed the ability of the aspheric intraocular lenses to correct the positive spherical aberration of the cornea, with variable impact on the total eye wavefront but with constant advantages in the optical quality of the eyes as measured by the Modulation Transfer Function, the Point Spread Function, and the contrast sensitivity of implanted patients. Theoretical studies on model eyes underlined some possible limitations of aspheric intraocular lenses, especially sensitivity to decentration. In addition, the actual optical quality in implanted eyes is also affected by light scattering, a parameter missed by simple aberration analysis. Summary Aspheric intraocular lenses effectively reduce spherical aberration in implanted eyes, with improvement in optical quality over the parent spherical intraocular lens. The advantages for implanted eyes could be limited by decentration, by small pupil diameter, and by reduced media transparency.

Experimental corticosteroid ocular hypertension in the rabbit.

Weekly subconjunctival injections of 4mg repository betamethasone, repeated over three weeks, produced a sustained increase of intraocular pressure (IOP) in 96 % of the treated rabbits. Treatment was generally well tolerated and important systemic toxic effects were present only in a few animals. The ocular hypertension so obtained was constant, well reproducible and sensitive to antiglaucoma drugs. The authors believe they have developed an animal model which is very suitable for testing the pressure-lowering effect of drugs and for other studies on ocular hypertension and glaucoma.

Intraocular penetration of topical lidocaine 4

PURPOSE To evaluate the intraocular penetration of lidocaine 4% topically applied before phacoemulsification. SETTINGS Institute of Ophthalmology, University of Verona, and Department of Medical Pharmacology, University of Padua, Italy. METHODS Thirty eyes having phacoemulsification for senile cataract were anesthetized by topical application of lidocaine 4%. The drug was applied 3 times in 30 minutes in 15 eyes and 6 times in 60 minutes in 15 eyes. At the beginning of surgery, aqueous humor samples were obtained to measure the lidocaine levels. Blood samples were obtained in 6 patients 30 and 60 minutes after aqueous humor collection. The aqueous humor levels were compared with the amount of pain perceived by patients during surgery. RESULTS Mean aqueous humor lidocaine concentration was 8.68 micrograms/mL +/- 2.43 (SD) after 3 instillations and 23.21 +/- 8.87 micrograms/mL after 6 instillations. Blood levels of lidocaine were negligible. Patients whose intraocular level was below 12 micrograms/mL perceived more pain during surgery. Only 2 eyes had these low levels after 6 instillations. CONCLUSIONS Topically applied lidocaine 4% effectively penetrates the eye, providing analgesia for phacoemulsification. We suggest at least 6 instillations in the hour preceding surgery. In this study, pain during surgery was primarily related to poor intraocular levels of the anesthetic agent.

Pseudoaccommodation with the 3M diffractive multifocal intraocular lens: a refraction study of 52 subjects.

ABSTRACT A refraction study was performed of 52 pseudophakic subjects implanted with a 3M diffractive intraocular lens (IOL). Twenty patients implanted with conventional monofocal IOLs from 3M were used as controls. The refraction for distance and near was determined, corresponding to the refractive (distance vision) and diffractive (near vision) foci. Pseudoaccommodation amplitude was measured relative to the variation of visual acuity as a function of “fogging” obtained with plus and minus lenses over any required spherical cylindrical power. Results showed that the 3M diffractive IOL acted as a bifocal lens in all subjects except those whose IOLs had decentered markedly. The dioptric range allowing good vision for distance and near is much wider with the diffractive IOL than it is with a monofocal IOL. Almost perfect vision, and the satisfaction of the patients, was achieved when the distance refraction was near to emmetropia and astigmatism was minimal. However, hyperopic biometric inaccuracies were less disturbing than myopic inaccuracies.