Thomas O. Wood

Effect of intraocular lens convexity on posterior capsule opacification.

ABSTRACT A consecutive series of 248 eyes undergoing extracapsular cataract surgery and posterior chamber lens implantation were evaluated. One hundred eight eyes had the implant placed with the convex side posterior and 140 with the convex side anterior. The incidence of capsulotomy required in the convex posterior group was significantly less than in the convex anterior group, 17.6% versus 29.3% (P value < 0.05). The type of posterior capsule opacification in the two groups was also different. In the convex posterior group, a smooth fibrous type of capsular opacification predominated; in the convex anterior group, epithelial proliferation and pearl formation as well as wrinkling of the capsule frequently occurred. The difference in opacification was reflected in the preoperative visual acuity: convex posterior 20/80, convex anterior < 20/200 (P < 0.05).

Postkeratoplasty Astigmatism Control: Single Continuous Suture Adjustment versus Selective Interrupted Suture Removal

Two different suturing techniques performed during keratoplasty were retrospectively evaluated to compare postkeratoplasty astigmatism, number of suture manipulations, and time to optical stability. One group of patients (n = 31) received a combination of continuous 11.0 nylon suture and 12 or 16 interrupted 10.0 nylon sutures (CCIS), which were selectively removed post-operatively to reduce astigmatism. The second group of patients (n = 26) received a single continuous 10.0 nylon suture (SCS) that was adjusted postoperatively at the slit lamp to regulate corneal astigmatism. Compared with the CCIS technique, adjusting the single continuous suture resulted in less postoperative astigmatism (SCS, 1.5 +/- 1.1 diopters [D]; CCIS, 3.2 +/- 1.9 D), fewer suture manipulations per patient (SCS, 0.9 +/- 0.7; CCIS, 3.8 +/- 1.8), and earlier optical stability for visual rehabilitation (SCS, 2.6 +/- 1.5 months; CCIS, 9.6 +/- 4.7 months) (P less than 0.01). No continuous sutures were broken during adjustment. The adjustable single continuous suture may offer an improved method for early control of postkeratoplasty astigmatism.

Salzmann??s Nodular Degeneration

Fifteen eyes in 12 patients with Salzmanns nodular corneal degeneration developed symptoms of recurrent erosion, decreased vision, or both. A history or evidence of ocular surface disease was present in 14 of 15 eyes. Removal of the nodule and accompanying pannus or corneal epithelial basement membrane degeneration, provided symptomatic improvement in all patients.

Cytochrome oxidase activity of Fuchs' endothelial dystrophy

The normal human corneal endothelial monolayer maintains stromal water equilibrium and thus, transparency, by means of a pump-leak mechanism. Water leaks into the stroma through non-tight lateral cell junctional complexes and is drawn out by an energy dependent cell membrane ion pump. We investigated the histochemical localization of cytochrome oxidase activity (CO), an important energy-deriving mitochondrial enzyme in dysfunctional corneas with Fuchs endothelial dystrophy (ED), which is a regionally distributed disease. Keratoconus corneas were used as controls for functional control endothelium. In the central area of the corneal button, decreased CO activity was demonstrated which correlated clinically with central corneal edema. This reflects decreased metabolic activity and/or decreased numbers of mitochondria in the attenuated dysfunctional cells. In the mid-periphery, CO activity was increased in the cellular rosettes surrounding guttata, which may be related to increased synthesis of abnormal Descemets membrane and guttata. Peripherally, the large polygonal cells resembled functional endothelium in their morphology and CO activity. We have, therefore, demonstrated regional differences in energy metabolism in endothelium from Fuchs ED patients which may be related to decreased numbers of mitochondria in the dysfunctional cells, and/or to synthesis of abnormal Descemets membrane material.

Cataract Formation Following Corneal Transplantation in Eyes with Fuchs?? Endothelial Dystrophy

In a retrospective analysis, 78 eyes in 58 patients that underwent corneal transplantation for Fuchs endothelial dystrophy were examined for the presence of cataracts. Follow-up ranged from I to 17 years, with an average of 6.62 years. Thirty-four (44.1%) of the eyes developed cataracts sufficient enough to require surgical removal. The mean time from transplant to cataract formation averaged 4.9 years. The average age at the time of transplant surgery in the eyes that did not develop cataracts was 55.6, and in those that developed cataracts, 60.3 (p = 0.049). Thirteen percent of the transplants lost transparency following cataract extraction. The incidence of postkeratoplasty cataract increased at age 50 and occurred in 75% of eyes grafted in patients 60 years of age or older.

Immunohistochemical localization of ATPase in human dysfunctional corneal endothelium

Previous light microscopic autoradiographic results from our laboratory have shown a quantitative decrease in ATPase pump site density in dysfunctional corneal endothelium. In order to develop antibody techniques to correlate these findings with electron microscopic localization of pump sites, three types of corneas with dysfunctional endothelium (Fuchs endothelial dystrophy, aphakic and pseudophakic bullous keratopathy) and two types of corneas with functional endothelium (age matched eye bank and keratoconus) were obtained at the time of transplant surgery. Corneas were fixed, frozen and cryostat sections were incubated in a rabbit kidney ATPase primary antibody followed by incubation in an HRP-labeled secondary antibody. Functional endothelia showed dense antibody labeling along the lateral cell membranes and there was a substantial reduction in labeling along the lateral membranes of dysfunctional endothelia. Positive tissue controls of rabbit kidney showed HRP reaction product in the convoluted tubules. Control tissue, incubated in either non-immune serum or primary antibody preabsorbed with ATPase, confirmed the specificity by having diminished or no reaction product. These results provide immunohistochemical confirmation of our autoradiographic data showing a quantitative reduction in pump site density on dysfunctional corneal endothelium.

A clinical index for predicting visual acuity after cataract surgery.

We developed a clinical index for predicting postoperative visual acuity of cataract patients and cross-validated it using data from 182 patients aged 70 years and older. The index consisted of four statistically combined indicators: age, preoperative visual acuity, frequency of reading, and comorbidity. Validation of the index included comparisons to two standard technical instruments for measurement of retinal visual acuity. For the clinical index, 72% of predictions were accurate within one Snellen line of postoperative visual acuity compared to 37% using a laser interferometer and 33% using a potential acuity meter. Testing of the clinical indexs external validity using data from 111 patients in a different ophthalmology clinic disclosed 61% of predictions accurate within one Snellen line.

Simultaneous penetrating keratoplasty, extracapsular cataract extraction, and intraocular lens implantation

ABSTRACT The postoperative results of 210 consecutive eyes in 177 patients who had simultaneous penetrating keratoplasty, extracapsular cataract extraction, and posterior chamber intraocular lens (IOL) implantation (triple procedure) were reviewed. All procedures were performed by one surgeon between January 1980 and December 1989. The most common diagnosis requiring a triple procedure was Fuchs endothelial dystrophy. The remainder of the patients required the procedure for either corneal scarring, keratoconus, or Chandlers syndrome. Of the 210 grafts, 191 (91%) remained clear with a mean follow‐up of 53 months (range 6 to 116 months). The mean preoperative keratometry (K) reading (n = 161) was 44.51/44.85 (SD 4.86/4.94), and the mean postoperative K reading (n = 111) was 44.29/43.50 (SD 3.83/3.63). The mean IOL power (n = 196) was +20.87 diopters (D) (SD 2.86). The mean postoperative best visual acuity (n = 166) was 20/65 with a range from 20/20 to < 20/400, although 61% had 20/50 acuity or better and 92% had 20/100 acuity or better. The mean spherical correction in 155 eyes was −1.38 (SD 2.89), and the mean positive refractive cylinder was +3.21 (SD 2.20). One hundred forty six of the 155 eyes with reported refractions (96%) had 6 D or less of refractive cylinder. Correlation of the recipient‐donor disparity % and refractive cylinder was significant such that as disparity increased refractive cylinder increased (r = 0.197, P = .021). Correlation of the recipient‐donor disparity % and keratometric cylinder indicated a similar trend but was not significant (r = 0.105, P = .310).

Anterior stromal micropuncture electron microscopic changes in the rabbit cornea.

Anterior stromal micropuncture has become an effective treatment for recurrent erosion. The healing process in rabbit corneas was investigated. Following micropuncture of the corneal surface with a 27-gauge needle knife, electron microscopy was carried out at regular intervals from time 0 through 5 months. The corneal incisions began to fill with epithelium by day 1. Activated keratocytes were adjacent to the basement membrane defect by 7 days. The basement membrane appeared to be healed at 2 and 4 weeks. Epithelial projections into the stromal incisions with underlying mature basement membrane persisted at 5 months postsurgery. Basement membrane reproduction occurred much more rapidly following needle puncture than after microdiathermy. This was thought to occur because the corneal epithelial cell was immediately exposed to type I collagen, whereas following microdiathermy, new type I collagen must be secreted on the necrotic collagen before the corneal epithelium will secrete basement membrane.

Effect of carbachol on postoperative intraocular pressure

ABSTRACT Carbachol instilled in 125 eyes at the time of extracapsular cataract extraction and posterior chamber lens insertion had a statistically significant effect on lowering the postoperative intraocular pressure JOP) at 24 hours (average IOP 14.0 mm Hg) and at 72 hours (average IOP 11.6 mm Hg) (P <.001). The percentage of patients with an acute IOP elevation at 24 hours was also significantly reduced: carbachol 10% versus control 33% (P=.001). Carbachols prolonged lowering of postoperative IOP may increase the safety of cataract surgery, particularly in patients with compromised optic nerves.