Michael Blumenthal

Effect of a plano-convex posterior chamber lens on capsular opacification from Elschnig pearl formation

ABSTRACT Opacification of the posterior capsule occurs most commonly from Elschnig pearl migration or fibrosis. The physical contact of a posterior chamber lens, particularly one with a reverse optic, has been postulated to decrease the rate of capsular opacification by creating a barrier to Elschnig pearl migration. This randomized prospective clinical study comparing the 3M style 34S convex‐plano optic and style 34R plano‐convex (reverse) optic posterior chamber lens demonstrated a statistically significant reduction in capsular opacification by Elschnig pearls at one year in the reverse optic lenses (18.2% versus 7.6%, P = .03). No statistically significant difference in capsular fibrosis rates was noted (2.5% versus 4.5%, P = .48). The reverse optic implant also demonstrated greater iris to implant optic clearance.

Postoperative Complications After Molteno Implant Surgery

We performed Molteno implant surgery in one eye each of 41 patients with uncontrolled glaucoma. Intraocular pressure was controlled (intraocular pressure less than or equal to 18 mm Hg) in 32 eyes (78%). The mean preoperative intraocular pressure was 40 +/- 13.2 mm Hg, whereas the mean postoperative intraocular pressure was 16 +/- 6.6 mm Hg. Patients were followed up for an average of 16 months after the operation. Visual acuity was unchanged in 23 eyes (56%), improved in nine eyes (22%), and poorer in nine eyes (22%). The major complications included shallow anterior chamber and hypotony in six eyes (14.6%), vitreous hemorrhage in two eyes (4.9%), retinal detachment in one eye (2.4%), and malignant glaucoma in two eyes (4.9%). Less grave complications included hyphema in four eyes (9.8%), peripheral choroidal effusion in 15 eyes (36.6%), obstruction of the tube in six eyes (14.6%), recession of the tube into the angle in two eyes (4.9%), erosion of the tube in one eye (2.4%), and Tenons cyst formation in three eyes (7.3%).

Tight Scleral Flap Trabeculectomy With Postoperative Laser Suture Lysis

Thirty eyes of 30 patients underwent tight scleral flap trabeculectomy. Of these eyes, 22 underwent laser lysis of the scleral flap sutures, whereas eight eyes did not require such treatment because of low intraocular pressure and active filtering blebs. In the 22 eyes treated, preoperative intraocular pressure was 32.6 +/- 8.3 mm Hg, whereas postoperative and pre-laser intraocular pressure was 29.3 +/- 7.4 mm Hg. Immediately after laser suture lysis, intraocular pressure dropped by 22.7 +/- 9.4 mm Hg (P less than .01) to 6.6 +/- 7.0 mm Hg, with elevation of the conjunctival bleb in all eyes treated. After a mean follow-up of 14.4 months, intraocular pressure was controlled (less than or equal to 18 mm Hg) in 20 of the 22 eyes treated (91%). The only major complication was a single case of anterior chamber flattening with intraocular lens touching the corneal endothelium. Combination of tight scleral flap trabeculectomy with subsequent postoperative laser suture lysis is a safe and effective method for low-level intraocular pressure control. This technique seems to combine the advantages of full-thickness filtration and trabeculectomy by achieving relatively low intraocular pressures while minimizing complications caused by excessive aqueous runoff.

Management of Descemet's membrane detachment

Abstract Detachment of Descemet’s membrane is a rare but serious complication of cataract surgery. Most surgeons attempt to reposition the membrane by injecting air, slow‐reabsorbing gases, or viscoelastic substances into the anterior chamber. We describe five cases of subtotal detachment without rolled scroll. These cases recovered spontaneously after two to three months. We believe that conservative treatment in such cases is indicated and has a good a chance of favorable outcome.

Small-incision manual extracapsular cataract extraction using selective hydrodissection.

Hydrodissection is a technique in which balanced salt solution is injected through a cannula into various layers of a cataractous lens to separate the lens lamella in a nonspecific location. Selective hydrodissection allows separation of the lens lamella at different desired anatomical layers. The technique allows the smallest possible nucleus, ie, the hard-core nucleus, to be hydroexpressed as a separate entity, requiring, correspondingly, a relatively small capsulorhexis and limbal incision. Then, in a second maneuver, the epinucleus, which engulfs the hardcore nucleus to form the adult nucleus, also can be aspirated or hydroexpressed as a whole. Selective hydrodissection permits scleral incision and stitchless surgery in planned extracapsular cataract extraction and also may serve as an intermediate step for surgeons who wish to convert to or learn phacoemulsification techniques.

Risk Factors Associated With Late Infection of Filtering Blebs and Endophthalmitis

Late infection of filtering blebs and endophthalmitis are hazardous complications of glaucoma filtering surgery frequently associated with bleb failure and loss of functional vision. To determine possible risk factors for the development of these complications, characteristics of nine eyes of nine patients after filtering surgery in whom late endophthalmitis developed were compared with those in patients who had received a comparable operation at the same time in whom endophthalmitis did not develop. An average of 7.7 +/- 6.2 years (range, 6 months to 18 years) elapsed between the time of the filtering procedure and the initial appearance of endophthalmitis. Factors associated with increased risk were: increased axial length, thin and leaky bleb, conjunctivitis, upper respiratory infection, and the winter season.

Three year results of photoastigmatic refractive keratectomy for mild and atypical keratoconus

Purpose: To evaluate the long‐term effect of photoastigmatic refractive keratectomy (PARK) on mild keratoconus. Setting: Laser Unit, Ein Tal Eye Center, Tel Aviv, Israel. Methods: Eight eyes of 6 patients with stable compound myopic astigmatism and topography features of keratoconus were treated with a VISX Twenty‐Twenty excimer laser. The laser beam slit width ranged between 4.8 and 5.0 mm according to the degree of cylinder. Preoperative slitlamp examination did not reveal significant thinning, ectasia, or scarring. Astigmatism ranged between ‐2.00 and ‐7.50 diopters and follow‐up, between 36 and 48 months. Results: In 7 of 8 eyes, uncorrected visual acuity (UCVA) before PARK ranged between 6/30 and finger counting. After PARK, it ranged between 6/9(‐) and 6/15, and patients could manage in most of their daily activities without using spectacles. In 2 eyes, the final UCVA was 6/15(‐) and 6/15. In 1 eye, treatment failed to improve UCVA and corneal topography revealed progression of the keratoconus. Conclusions: Photoastigmatic keratectomy was partially effective in eyes with mild stable keratoconus. However, the long‐term results may be altered by progression of corneal thinning and ectatic disease. In addition to the mild nature of the keratoconus, this is a small series and further studies are needed to confirm these results.

Using an anterior chamber maintainer to control intraocular pressure during phacoemulsification

Abstract We describe a phacoemulsification technique that uses an anterior chamber maintainer (ACM) to control intraocular pressure. Continuous irrigation through the ACM maintains pressurized intraocular conditions throughout surgery and when the automated system is not activated. Intraocular pressure is stabilized at predetermined levels with minor fluctuations. Viscoelastics can be used in conjunction with the ACM.

The Round Capsulorhexis Capsulotomy and the Rationale for 11.0 mm Diameter IOL

It is generally accepted that the optimal location of the IOL is in the capsular bag. This location is advantageous only if the IOL remains permanently in the capsular bag. The anatomical factors directing guidelines for a 5.0–6.0 mm round capsulotomy are: anterior posterior position of the crystalline lens, zonular frontier and zonular pull. To express the nucleus without the danger of capsular tears, use of the closed system technique which permanently maintains the volume and the pressure by using an anterior chamber maintainer is recommended. Thus hydrodissection and hydroexpression of the nucleus through small limbal incision are facilitated, without tear at the capsulotomy margin. The dimension of the crystalline capsular bag changes from 9.6 mm to 10.7 mm after ECCE. Thus 11.0 mm loop-to-loop lenses are advocated. Uncertainty about secure ‘in the bag’ implantation is the reason for the use of 13.0–14.0 mm lenses at present. As more surgeons are mastering round capsulorhexis capsulotomy, a greater number will find it safe to use 11.0 mm new design lenses with asymmetrical loops. In fact, there would be no reason not to implant 11.0 mm lenses.

Corneal endothelial cytotoxicity of diluted povidone–iodine

Purpose: To assess corneal endothelial toxicity of diluted povidone–iodine (PI) in vivo and in vitro. Setting: Cell Biology Laboratory and the Laboratory for Intraocular Microsurgery and Implants, Goldschleger Eye Research Institute, Sackler School of Medicine, Tel‐Aviv University, Chaim Sheba Medical Center, Tel‐Hashomer, Israel. Methods: In an in vitro study, cultured bovine corneal endothelial cells were exposed to diluted PI. The degree of cell damage was determined by staining with trypan blue and by comparing the results to those in a control group. In an in vivo study, a single dose of diluted PI was injected into the anterior chamber of rabbit eyes, completely replacing the aqueous humor. The eyes were evaluated by clinical examination, specular microscopy, pachymetry, pneumotonometry, and histopathology and compared to a control group injected with a balanced salt solution. Results: In vitro, PI concentrations of 0.05% or less did not induce endothelial cell damage. Significant damage was observed with a PI concentration of 0.1%. Calf serum concentrations of 1% and higher in the culture media protected the endothelial cell monolayer from cytotoxic damage by PI. Aqueous humor did not have a similar effect. In vivo, PI concentrations of 0.1% or less did not induce changes in corneal endothelium morphology or function as assessed by specular microscopy and pachymetry. A PI concentration of 1% served as a positive control, causing corneal edema and endothelial cell loss as demonstrated by pachymetry, histopathology, and elevated intraocular pressure. Conclusions: The concentrations of PI tolerated by animal endothelium in vitro and in vivo were higher than the reported bactericidal levels. These findings justify further investigation of the safety and efficacy of PI for intracameral prophylaxis during surgery.