Mamoru Matsuda

The Effects of Hard and Soft Contact Lenses on the Corneal Endothelium

We examined the morphologic characteristics of the corneal endothelium in three groups of contact lens wearers: those who had used daily-wear soft contact lenses for an average of 6.3 years, long-term (greater than 20 years) users of hard contact lenses, and former users of hard contact lenses who had worn them for an average of 9.6 years but who had discontinued them for an average of 4.3 years. When compared to age-matched controls, all groups had similar endothelial cell densities but demonstrated significant increases in variation of cellular size (polymegethism) and shape (pleomorphism). We found that daily-wear soft contact lenses can cause endothelial polymegethism and pleomorphism similar to those caused by hard contact lenses and that the endothelial changes induced by hard contact lenses are more profound with greater duration of wear and are apparently not completely reversible.

Serial alterations in endothelial cell shape and pattern after intraocular surgery

We serially examined the endothelial cellular pattern and thickness of the central cornea after intracapsular cataract extraction and penetrating keratoplasty. The endothelial cellular pattern was analyzed with a computer-assisted digitizer. We used the frequency of hexagonal cells as the index to describe the degree of hexagonality in the cellular pattern. In the intracapsular cataract extraction group (20 eyes), the frequency of hexagonal cells was 68% preoperatively. During the first four weeks this frequency decreased rapidly to a significantly lower level (52%). The corneal thickness was significantly increased within the first week (0.57 mm) and steadily decreased to preoperative values at four weeks (0.53 mm). During the period from four to 24 weeks, the frequency of hexagonal cells increased gradually to 64%. In the penetrating keratoplasty group (ten eyes), the frequency of hexagonal cells and the thickness at one month were 62% and 0.64 mm respectively. During the next six months the frequency of hexagonal cells decreased significantly to 53%, and the thickness decreased to 0.53 mm. There was a gradual increase in the frequency of hexagonal cells to 62% during the two years after penetrating keratoplasty.

Quantitative Analysis of Endothelial Mosaic Pattern Changes in Anterior Keratoconus

The corneal endothelia of 21 eyes with anterior keratoconus and 15 eyes of age-matched controls were investigated with a specular microscope. Of the 21 eyes, 15 had definite keratoconus while six apparently normal fellow eyes were designated as latent. The corneal endothelial photographs were subjected to a computerized digitizer analysis of the area and shape of individual cells. The endothelium in keratoconus showed a significant increase in the extent of polymegethism (the coefficient of variation in cell area; 0.36 +/- 0.07) as compared with controls (0.24 +/- 0.03), with the mean cell area staying within normal limits. The relative frequency of hexagonal cells in keratoconus (50.5 +/- 5.7%) was significantly lower than that of controls (70.6 +/- 5.5%). Additionally, an increase of various cell shapes was noted, indicating that there was also a significant increase in cellular pleomorphism. In the latent group, alterations in cellular structure could not be detected by analysis of cell area when compared to controls. However, when these eyes were subjected to cell shape analysis and compared to fellow keratoconic eyes, both eyes showed similar pleomorphic characteristics. These results suggest that in the fellow eye in unilateral keratoconus, even when there are no ocular signs and symptoms, diagnosis can be made early with specular microscopy and computerized cell shape analysis.

Corneal Endothelial Changes in Pseudoexfoliation Syndrome

Using specular microscopy and computer-assisted morphometry, we studied 27 eyes with pseudoexfoliation syndrome, 17 apparently normal fellow eyes, and 15 eyes of matched normal subjects with no ocular disease other than senile cataract. Endothelium of the eyes with pseudoexfoliation syndrome showed significantly lower cell density than did the endothelium from control eyes. Endothelium of both eyes of patients with unilateral pseudoexfoliation syndrome showed significant morphologic changes in cell size (polymegethism) and shape variability (pleomorphism); these changes were essentially the same in overtly affected and apparently normal fellow eyes. The results suggested that the corneal endothelial changes are consistent and might serve as an early sign of the disorder.

Long-Term Corneal Endothelial Changes After Intraocular Lens Implantation

We studied the morphologic characteristics of the corneal endothelium in a series of patients who had undergone phacoemulsification with intraocular lens implantation performed by one surgeon. Specular microscopy and computer-assisted morphometry were performed preoperatively and three years after surgery. Nineteen eyes that received posterior chamber lenses with intracapsular fixation had a mean endothelial cell loss of 18.1%, without any significant change in cell size (polymegethism) or shape variability (pleomorphism). Implantation of anterior chamber lenses with the posterior capsule left intact (18 eyes) caused a similar degree of cell loss (23.5%) but caused marked polymegethism and pleomorphism of the cells. Endothelial cell loss (28.5%) and morphologic changes were greatest in five eyes that received anterior chamber lenses because of a rupture of the posterior capsule.

The Long-term Effects of Polymethylmethacrylate Contact Lens Wear on the Corneal Endothelium

PURPOSE The purpose of this study is to determine the long-term effects of polymethylmethacrylate (PMMA) contact lens wear on the corneal endothelium. The authors had noted previously advanced polymegethism and decreased cell densities in a few long-term PMMA contact lens wearers. They evaluated a large group of such lens wearers to determine the prevalence of polymegethism and reduced endothelial cell density within this lens-wearing population. METHODS The authors examined the morphologic characteristics of the corneal endothelium in 162 PMMA contact lens wearers or age-matched controls. Eighty-one subjects had worn contact lenses for more than 20 years. RESULTS Patients showed advanced polymegethism and pleomorphism compared with controls. Mean cell density in the contact lens-wearing group was not different from controls, but a significantly greater percentage of contact lens wearers (11%, 9 of 81 patients) had cell densities less than 2000 cells/mm2 compared with controls (2.5%, 2 of 81 patients), and were also significantly more likely to have severe polymegethism (coefficient of variation, > 0.60) and severe pleomorphism (frequency of hexagons < 40%). CONCLUSION This study is unique, in that it notes a subgroup of PMMA contact lens wearers who are more susceptible to significant morphometric changes and reduced endothelial cell densities with long-term contact lens use.

Aldose reductase inhibitor (CT-112) eyedrops for diabetic corneal epitheliopathy.

We treated two diabetic patients with corneal epithelial disorder that resisted conventional medical therapy with topical CT-112 (5-[3-ethoxy-4-pentyloxyphenyl]-2,4-thiazolidinedione), a newly synthesized aldose reductase inhibitor. One patient had developed recurrent corneal erosion after vitrectomy and the other had spontaneously developed superficial punctate keratopathy. The corneal lesion in each patient responded to topical CT-112 in two to four weeks and was almost cleared within two months. A similar corneal lesion recurred in both patients soon after CT-112 was discontinued, but it disappeared again when the drug was resumed.

Topical aldose reductase inhibitor for correcting corneal endothelial changes in diabetic patients.

BACKGROUND--Marked variations in cell size (polymegethism) and shape (pleomorphism) are characteristic of the corneal endothelium in diabetic patients and animals. METHOD--Wide field specular microscopy was used to evaluate the clinical efficacy of treating the diabetic corneal endothelium with topical instillation of 0.5% aldose reductase inhibitor, CT-112. RESULTS--Morphological variations (polymegethism and pleomorphism) of the endothelium in eight eyes from eight patients receiving CT-112 resolved within 3 months after initiation of treatment. In contrast, no change in endothelial morphology was noted in five eyes from five patients who received placebo. CONCLUSION--These observations suggest that aldose reductase may be involved in the aetiology of corneal endothelial variations in diabetic patients.

The effects of aldose reductase inhibitor on the corneal endothelial morphology in diabetic rats

Diabetic rats were produced by intravenous injection of streptozotocin. Of these, eleven rats were treated with topical instillation of 0.5% aldose reductase inhibitor (ARI), while ten received vehicle alone. The corneal endothelium of these diabetic rats was examined by specular microscopy and compared to age-matched nondiabetic rats (ten rats). Computerized morphometric analysis of individual cells demonstrated that the endothelium of the untreated diabetic rats had marked polymegathism (increased coefficient of variation in cell area) and pleomorphism (decreased percentage of hexagonal cells), as previously observed in diabetic patients. Similar endothelial changes were also noted in the ARI-treated diabetic rats, but to a significantly lesser extent. These results suggest that topically applied ARI can be effective in reducing morphologic changes of the diabetic endothelium, and that activation of the sorbitol pathway may be implicated in the etiology of such endothelial changes.

Effects of posterior chamber lens implantation on the endothelium of transplanted corneas

AIMS The morphological changes of the corneal endothelium after posterior chamber lens implantation in the transplanted corneas were investigated. METHODS 36 patients underwent extracapsular cataract extraction with posterior chamber lens implantation. Among these, penetrating keratoplasty had been performed in 18 patients before cataract surgery. The indications for penetrating keratoplasty in these cases included keratoconus, herpetic keratitis, and macula cornea. 18 cataract patients with normal corneas were also studied as controls. The central corneal endothelium in each subject was examined with a wide field specular microscope at a few days before and 3 months after cataract surgery. RESULTS Although the transplanted corneas showed lower endothelial cell densities, marked polymegethism, and pleomorphism in the baseline variables, the endothelial morphological changes in the transplanted corneas after posterior chamber lens implantation were comparable with those in the normal corneas. Also, there was no clinical evidence, especially, of corneal epithelial and/or endothelial rejections and corneal decompensation in all corneas. CONCLUSION Even though the transplanted corneas have a lower endothelial cell density and marked polymegethism, it is believed that cataract surgery does not induce corneal decompensation in cases where the peripheral recipient endothelium can be considered to have normal morphology.