Tamer A. Macky

Anterior capsule opacification: Correlation of pathologic findings with clinical sequelae

OBJECTIVE To evaluate the degree of anterior capsule opacification (ACO) in human eyes obtained postmortem containing various rigid and foldable posterior chamber intraocular lens (PC-IOL) designs and compare the findings with clinical sequelae of capsular shrinkage. DESIGN Comparative autopsy tissue study with clinicopathologic correlations. MATERIALS Three hundred formalin-fixed human eyes containing the following PC-IOL styles were analyzed: (1) one-piece polymethyl methacrylate (PMMA) optic-PMMA haptic (n = 50), one-piece silicone-plate IOL, with large (2) or small (3) fixation holes (n = 35), (4) three-piece PMMA optic-Prolene haptic (n = 50), (5) three-piece acrylic optic-PMMA haptic (n = 55), three-piece silicone optic with PMMA (6) or polyimide (7) haptics (n = 30), and (8) three-piece silicone optic-Prolene haptic (n = 80) lenses. TESTING The eyes were sectioned in the equatorial plane for gross examination of the capsular bag from a posterior view. The cornea and iris were then excised for evaluation from an anterior view. MAIN OUTCOME MEASURES ACO was scored in each eye from 0 to IV, according to the degree/area of capsule opacification. Capsulorrhexis size and IOL decentration were measured with calipers. RESULTS The overall differences among the IOL groups regarding the three parameters were significant (ACO score: P < 0.001; capsulorrhexis diameter: P = 0.036; IOL decentration: P = 0.012). Mean ACO scores were highest with the large- and small-hole one-piece silicone-plate lenses (2.543 +/- 0.950) and lowest with the three-piece acrylic optic-PMMA haptic lenses (0.600 +/- 0.710). Of 10 cases of capsulorrhexis phimosis observed in the study, 7 cases were associated with three-piece silicone optic-Prolene haptic lenses, which also presented the highest mean decentration (0.375 +/- 0.601 mm). CONCLUSIONS Our results confirm previous histopathologic observations that the rate of ACO is the lowest with acrylic lenses and higher with plate-haptic silicone IOLs. Nevertheless, clinical sequelae of capsular shrinkage are also very important with three-piece silicone optic-Prolene haptic designs. Thus, IOL material and design are significant factors in the development of ACO, but they ultimately also influence the clinical presentation of capsular shrinkage.

Pediatric cataract surgery and intraocular lens implantation : Current techniques, complications, and management

Congenital, early developmental and traumatic cataracts are common ocular ailments and represent an important cause of visual impairment in childhood (Fig 1). Pediatric cataracts can have different etiomorphological characteristics and have been reviewed extensively in the past by several authors. Managing cataracts in children remains a challenge; treatment is often difficult and tedious and requires a dedicated team effort by parents, pediatrician, surgeon, anesthesiologist, orthoptist, and community health workers. The surgeon plays a significant role in achieving a good visual outcome after the treatment of childhood cataracts. This chapter focuses on the management of pediatric cataracts, with an emphasis on the various surgical techniques used for intraocular lens (IOL) implantation and on postoperative complications and their management.

Calcification on the surface of the Bausch & Lomb Hydroview intraocular lens.

The overwhelming number of foldable intraocular lenses (IOLs) implanted or available today are of silicone optic design (e.g., the Allergan SI40 model, Irvine, CA), or hydrophobic acrylic design (e.g., Alcon AcrySof IOL [Alcon Laboratories, Fort Worth, TX]). Silicone-optic IOLs are generally excellent but are unsuitable for vitreoretinal patients, owing to possible interaction with silicone oil (see “Silicone Oil Adherence to Silicone Intraocular Lenses”) less hydrophobic than silicone but still are not immune to the complication. Hydrophobic acrylic IOLs of silicone oil interaction. Hence, the introduction of adequately hydrophilic IOL designs that are capable also of folding and being inserted via modern small-incision techniques would represent a major advance. Significant deposition of crystalline material on the surface of IOLs is uncommon. It has been reported to occur intraoperatively during cataract surgery with implantation of silicone IOLs or in the early postoperative period after implantation of hydrogel IOLs. The deposits described in the studies cited were composed of calcium hydroxyapatite, and the hypothesized pathogenetic mechanisms involved an oversupply of calcium and phosphate from intraocular solutions used during cataract surgery. At the Center for Research on Ocular Therapeutics and Biodevices,

Phakic posterior chamber intraocular lenses.

In an attempt to reduce the incidence of potential problems with phakic anterior chamber intraocular lenses, especially such sequelae as lens contact with the corneal endothelium and pupil ovalization, Fyodorov and coworkers introduced a phakic posterior chamber intraocular lens (PPCIOL) made of silicone, to be inserted between the iris and the crystalline lens. Fyodorov performed the first implantation of this silicone design IOL in a phakic eye to correct high-degree myopia in August 1986. The first models were, in fact, pupil-fixated lenses (mushroom lenses; Fig 1). To our knowledge, they were implanted in the Soviet Union from 1986 to 1990. These lenses were designed to be fixated in the ciliary sulcus but, as the optic had the shape of a collar-button with a small diameter (3.2 mm in the first model) and protruded into the anterior chamber, the pupil could not constrict anterior to the lens optic. The optic and haptics were connected by a bridge through the pupillary opening. This Fyodorov IOL was modified by Chiron-Adatomed (Munich, Germany) under the guidance of Zuev and Fechner (Fig 2). The Chiron-

Phakic anterior chamber intraocular lenses.

Implantation of phakic intraocular lenses(IOLs) has many advantages over such corneorefractive procedures as laser in situ keratomileusis. In the treatment of high myopia by the latter technique, large amounts of cornea must be ablated, small effective optical zones are created, and the predictability and stability of the procedure begin to diminish. With phakic IOL implantation, the refractive outcome may be influenced only by variations in postoperative astigmatism or by increments in length of the eyes. The potential reversibility or adjustability of phakic IOL implantation is absent in corneorefractive procedures (apart from intrastromal corneal ring segments). Limitations in predictability are related in part to the selection of phakic IOL powers on the basis of subjective refractions, unlike the routine calculation for aphakic IOLs. These refractions may be expected to be less reliable in eyes with more extreme levels of myopia. Coexisting astigmatism can be neutralized at the time of operation by varying the incision through which the lens is implanted. One of the most important advantages of phakic anterior chamber IOL implantation over such techniques as clear lens extraction with IOL implantation is the preservation of accommodation. Also, lensectomy with or without IOL implantation may increase the risk of retinal detachment and

Viscoanesthesia. Part I: Toxicity to corneal endothelial cells in a rabbit model

Purpose: To evaluate the toxicity of a solution combining sodium hyaluronate 1.5% with lidocaine (0.5%, 1.0%, or 1.65%) to the rabbit corneal endothelium. Setting: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. Methods: Each rabbit cornea was excised, and the endothelium was exposed to 1 of the following solutions for 20 minutes: viscoanesthetic solution (0.5%, 1.0%, or 1.65% lidocaine in sodium hyaluronate 1.5%; 5 corneas each), sodium hyaluronate 1.5% (n = 5), balanced salt solution (BSS®) (n = 5), mitomycin‐C 0.02% (n = 2), dextran 15% (n = 2), or distilled water (n = 2). The endothelium was then stained with trypan blue and alizarin red. Two corneas were stained immediately after excision. Cell morphology and damage to the corneal endothelium were analyzed by microscopic examination. Results: The endothelium in the corneas of the viscoanesthetic groups was comparable to that in the sodium hyaluronate 1.5% and the BSS groups and to the corneas not exposed to any solution. In some areas of the 1.0% and the 1.65% viscoanesthesia groups, the corneal endothelial cells presented irregular intercellular borders. Staining with trypan blue, which indicates cellular damage, was observed in some linear areas corresponding to corneal folds in all groups. The folds were probably caused during manipulation for corneal excision and staining. The corneal endothelium was destroyed in the mitomycin group. In the dextran and distilled‐water groups, morphological alterations probably resulting from osmotic changes were observed. Conclusion: The 3 concentrations of viscoanesthetic solutions appeared to be safe to rabbit corneal endothelium.

Degeneration of ultraviolet absorber material and calcium deposits within the optic of a hydrophilic intraocular lens

Foldable hydrogel (hydrophilic acrylic) intraocular lenses (IOLs) are not yet available in the United States but have been marketed by several firms for several years in international markets. In the chapter, “Calcification on the Surface of the Bausch & Lomb Hydroview Intraocular Lens,” we discussed late postoperative opacification due to crystalline deposition on the optical surface of one of these lenses, the Bausch & Lomb Hydroview IOL. In this chapter, we discuss late postoperative opacification within the optic substance of some IOLs manufactured from at least one source of a hydrophilic acrylic biomaterial. This complication has recently been reported and was presented also at the annual meeting of the German Ophthalmic Surgeons in June 2000. The hydrophilic IOL (known also as a hydrophilic acrylic IOL style) most recently associated with clinically significant postoperative opacification within the optic is a one-piece design. The source of the polymer is Vista Optics, Cheshire, UK; the manufacturer and distributor is Medical Developmental Research (MDR Inc., Clearwater, FL, USA). Chang and colleagues have reported 1 case of clouding and fogging of this IOL design. They noted an opacification associated with significant visual loss that

Viscoanesthesia. Part III: Removal time of OVD/viscoanesthetic solutions from the capsular bag of postmortem human eyes

Purpose: To investigate and evaluate the removal time of various ophthalmic viscosurgical device (OVD)/viscoanesthetic solutions containing sodium hyaluronate 1.5% with different concentrations of lidocaine (0.5%, 1.0%, and 1.65%). Setting: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. Methods: Six postmortem human eyes were prepared per the Miyake−Apple posterior video technique. Capsulorhexis, hydrodissection/delineation, and nuclear emulsification were performed, followed by thorough cleaning of the capsular bag using an irrigation/aspiration (I/A) tip. The time and ease of removal of 4 solutions from the capsular bag were evaluated. The solutions were Ophthalin Plus® (sodium hyaluronate, 15 mg/mL) and sodium hyaluronate 15 mg/mL mixed with lidocaine 0.5%, lidocaine 1.0%, and lidocaine 1.65%. The solutions were dyed with fluorescein to enhance visualization. After the capsular bag was filled with 1 of the solutions, a posterior chamber intraocular lens was implanted. The solution was then aspirated using an automated I/A device set at 250 mm Hg of aspiration. The time required to remove most and then all the material was recorded. Results: The mean time required for removal of most of the Ophthalin Plus, viscoanesthesia 0.5%, viscoanesthesia 1%, and viscoanesthesia 1.65% solutions was 8.7 seconds ± 2.1 (SD), 7.7 ± 1.1 seconds, 9.7 ± 0.6 seconds, and 6.3 ± 1.5 seconds, respectively (P = .1). The mean time to remove all the solutions was 21.3 ± 3.2 seconds, 19.7 ± 2.5 seconds, 18.3 ± 3.2 seconds, and 15.7 ± 2.1 seconds, respectively (P = .166). No subjective difference in viscosity or consistency was found among the solutions. Conclusion: The addition of lidocaine to the OVD solution did not significantly alter the viscosity or consistency of the solution or change its removal time from the capsular bag.

Pattern of uveitis in an Egyptian population with multiple sclerosis: a hospital-based study.

Purpose: To investigate the prevalence and pattern of uveitis in patients with multiple sclerosis (MS). PatientsandMethods: This is a cross-sectional, observational, descriptive clinical study of patients with MS who had complete ophthalmological examination. Data collected comprised demographics of the patients and complete ocular examination findings. Exclusion criteria were history of ocular surgery, trauma or diagnosis of any other ocular pathology. Results: Seventy-five patients with a mean age of 32.64 years (ranging from 16 to 50) diagnosed with MS of the relapsing-remitting type were included in this study. There were 34 males and 41 females, a ratio of 5:6. The mean duration of the MS disease was 5.6 years. Eight eyes of 7 patients with a mean age of 20 years had intermediate uveitis, of which 5 were males. Out of the 7 patients, 5 had exacerbated MS, and 2 were in remission; 4 had relative afferent pupillary defect. In the 8 eyes with uveitis, 6 had a best spectacle-corrected visual acuity (BSCVA) of 1, 1 had a BSCVA of 0.5 and 1 had a BSCVA of 0.25. Conclusion: Uveitis occurs in about 10% of patients with MS affecting younger males with exacerbated disease. Most inflammations of the uveitic MS patients were in the form of intermediate uveitis that was controlled with medication with no visual threatening complications.

Epidemiology of diabetic retinopathy in Egypt: a hospital-based study.

Purpose: To determine the prevalence and determinants of diabetic retinopathy (DR) in patients ≧18 years at the Cairo University and Sixth of October University hospitals. Patients and Methods: This is a cross-sectional survey among known diabetic patients attending diabetic clinics. Patients were randomly selected to complete an interviewer-administered questionnaire and a medical assessment. All patients had a dilated fundus examination for evidence of DR using slit-lamp biomicroscopy. Results: A sample of 1,325 patients was selected with a mean age of 49 years (SD ±12.9). DR was found in 20.5% of patients. Most patients (82%) were not aware of the hazards of diabetes mellitus for the eyes. The prevalence of DR was statistically significantly higher in females (22 vs.17%, p < 0.05), with longer diabetes disease duration (p < 0.001), hypertension (p < 0.001) and absence of hypertension control (p < 0.001), especially proliferative DR. Increasing age and poor glycemic control were associated with a nonsignificant increase in the rate of DR (p = 0.340 and p = 0.444, respectively). Conclusion: The prevalence of DR in our study population is 20.5%. Regular screening is highly recommended for early detection of DR where timely laser photocoagulation is known to reduce the risk of visual loss in these patients.