Results of a combined procedure for cataract and glaucoma, using Crozafon-De Laage punch.

PURPOSE: Study the efficacy and safety of a combined procedure for coexisting cataract and open angle glaucoma. METHODS: Forty eyes of 33 patients with cataract and coexisting open angle glaucoma underwent phacoemulsification and trabeculectomy with Crozafon-De Laage punch. Data was recorded from the patients' hospital files and from a questionnaire answered by the patients' regular ophthalmologist. RESULTS: After a mean follow-up time of 20.6 months (SD 4.9, range 12-31) the mean reduction in number of anti glaucoma drugs was 1.2 (SD 1.2) from 2.6 (SD 0.71) before operation to 1.4 (SD 1.12) at last visit (p<0.001). During the same period the mean intraocular pressure (IOP) was reduced from 18.9 (SD 5.2) mm Hg to 14.9 (SD 2.9) mm Hg (p<0.001). The mean visual acuity was preoperatively 0.24 (SD 0.21) and 0.60 (SD 0.35) at last visit. The reasons for visual acuity lower than 0.8 was mainly age related macular degeneration (AMD) and glaucoma. No serious sight threatening complications were seen. CONCLUSIONS: Combined phacoemulsification and trabeculectomy with Crozafon-De Laage punch is a safe and effective method for improving both visual acuity and control of intraocular pressure in coexistent cataract and open angle glaucoma.

Regeneration of epithelial defects in corneas previously treated with excimer laser. A study of cell kinetics in the rat corneal epithelium.

PURPOSE: The present study was to investigate, using cell kinetic methods, whether previous excimer laser treatment affected healing of later corneal epithelial erosions. METHODS: The right eyes of rats underwent central excimer corneal stromal-epithelial ablations (ArF 193 nm, 228 pulses, diameter 3,5 mm, 17,3 mJ per pulse, depth about one third of corneal thickness) and were allowed to heal for 15 weeks. Then central circular epithelial abrasions (diameter 3 mm), using N-Heptanol and mechanical debridement, were made on both corneas. The rats were killed 1,2,4 and 6 days after the last treatment. The central stromal thickness, the epithelial cell density, the labelling index (LI) and the mitotic rate (MR) of the peripheral, the midperipheral and the central areas of the corneal epithelium were calculated for each timepoint. RESULTS: The central stromal thickness increased equally in the two groups the first day after making the erosion, normalising in both groups during the following days. The corneal epithelium was restored at the same rate in both groups. The cell number per microscopic visual field, the LI and the MR were very similar for the two groups at all timepoints. CONCLUSION: Previous excimer laser treatment does not seem to interfere with healing of later epithelial erosions, when studied with cell kinetic methods.

Contrast sensitivity after implantation of diffractive bifocal and monofocal intraocular lenses.

PURPOSE: To compare contrast sensitivity (CS) after implantation of a diffractive bifocal intraocular lens (IOL) and a monofocal IOL of similar design. SETTING: Seven European centers. METHODS: In this randomized, prospective study, CS was tested 5 months after cataract and IOL implantation surgery in 115 patients with a diffractive bifocal IOL and 106 patients with a monofocal IOL. It was also tested in a subgroup of 38 patients who had bilateral implantation of a diffractive bifocal IOL. Contrast sensitivity was tested using the Vision Contrast Test System (VCTS). RESULTS: In patients with a best corrected visual acuity (BCVA) of 1.0 or better, the CS at all spatial frequencies (1.5 to 18 cycles/degree), both at distance and near, was slightly lower in the bifocal IOL group than in the monofocal group. Mean values were within the normal range. In patients with a BCVA of less than 1.0, the CS was lower and the difference between the bifocal and monofocal groups was less. In patients with bilateral bifocal IOLs, CS was better when tested bilaterally than when testing the better eye alone. Pupil size affected the results to a small degree. Contrast sensitivity appeared to improve over time after implantation of a diffractive bifocal IOL. CONCLUSIONS: In patients with cataract and no other eye pathology, the diffractive bifocal IOL with slightly reduce the CS at all spatial frequencies. In those with reduced visual acuity after cataract surgery, CS will be reduced accordingly. In this situation, the reduction from the diffractive bifocal optic would be minor.

Epithelial wound healing of the rat cornea after excimer laser ablation.

Rats with excimer corneal ablations (ArF 193 nm, 228 pulses, diameter 3,5 mm, 17.3 mJ per pulse, depth about 1/2 of corneal thickness) in one eye were killed 1, 2, 4, 6 and 13 days after treatment. The other eye served as control. The cell number per microscopic vision field, the labelling index (LI) and the mitotic rate (MR) were calculated for the peripheral, midperipheral and central areas of the corneal epithelium. The cell number showed a uniform depression in the remaining corneal epithelium at Day 1, normalizing from the centre to the periphery. The LI was only significantly increased at Day 1, while the MR was statistically significantly increased peripherally at Day 2 and in all areas at Day 6. However, when the corneal epithelium was evaluated as a whole, the MR was significantly increased at days 1, 2 and 6. The proliferative response of the epithelium was very homogenous irregardless of the distance to the original lesion. Both the migratory and the proliferative phases of the healing process seemed to be delayed when compared to the healing of pure epithelial wounds. However, the initiation of an increase in DNA synthesis seems not to be delayed, indicating that it is primarily the G2 phase that has been prolonged with this ablation procedure. The stromal thickness was increased from about one half of the normal values immediately after the treatment to above normal values at Day 4, thereafter decreasing to normal values at Day 13. Thus, the regenerative ability of the stroma is more pronounced in rats than in humans, but also in humans regeneration of the stroma can possibly explain the regression of the myopic shift seen some time after excimer laser treatment.

Time dependency in the regenerative response to injury of the rat corneal epithelium.

In the present study a central corneal epithelial defect (diameter 3.5 mm) was made in both eyes at 12:00 h in one group of rats and at 24:00 h in another group to see if the regenerative proliferation is influenced by circadian rhythms. The labeling index and the mitotic rate were registered at 4-h intervals in the perilimbal conjunctiva, the limbal area, and different parts of the cornea from the following morning until noon the day after that. The most pronounced regenerative proliferation was seen in the midperipheral and peripheral cornea. The regenerative response occurred in both groups 24-28 h after the injury, but was highly influenced by the normal circadian rhythms, especially with regard to the mitotic rate. The results support the theory that even regeneration is influenced by a circadian proliferative factor.

Use of collagen shields in cataract surgery.

A randomized, prospective, multicenter study evaluated the efficacy and safety of using collagen shields to deliver drugs after cataract surgery. Collagen shields saturated with an antibiotic and a steroid were placed in 90 eyes postoperatively. A control group of 93 eyes received the same drugs through a peribulbar/retrobulbar injection. One day after surgery, the shield group had significantly less corneal edema, conjunctival hemorrhaging, and postoperative pain and fewer corneal opacities. All symptoms except the conjunctival hemorrhaging disappeared by day seven. Our study suggests that using collagen shields for drug delivery after cataract surgery decreases tissue damage and increases patient comfort without adverse side effects.

Cell kinetics of conjunctival and corneal epithelium during regeneration of different-sized corneal epithelial defects.

Rats with small (diam. 1.7 mm), medium sized (diam. 3.5 mm) or large (diam. 5.5 mm) corneal epithelial erosions in one eye were killed 1, 2 or 4 days after the injury. The proliferative response was evaluated by measuring the labelling index and the mitotic rate in the corneal epithelium and in the adjacent conjunctiva. The small erosions triggered a proliferative response in the cornea only with the maximum response occurring midperipherally. The medium sized erosions induced a higher and more extensive response in the cornea and also a slight increase of the labelling index in the limbal area. The large erosions induced an even more pronounced response in the peripheral cornea and an increase both of the labelling index and the mitotic rate well beyond the limbal part of the conjunctiva. It is concluded that the magnitude and the extent both of the conjunctival and the corneal regenerative response to a corneal abrasion is correlated to the size of the corneal defect. Temporary reduction in the conjunctival epithelial cell number shows that both cells in the limbal and the extralimbal conjunctiva migrate centripetally during healing of large corneal wounds. It is suggested that the stem cell theory should be modified. The limbal area is probably an area in which conjunctival epithelial cells or conjunctiva-derivated cells transform or differentiate to corneal epithelial cells.

Apoptosis in the rat corneal epithelium during regeneration. A transmission electron microscopic study.

In the present transmission electron microscopic study, regenerating rat corneal epithelium is examined at three different time points after chemical abrasion. Four days after the initial injury classical signs of regeneration are observed. At day 6 regeneration is less pronounced and epithelial differentiation dominates the morphological picture. Many basal cells are swollen and single electron-dense basal cells have a shrunken morphology (dark cells). Intercellular cytoplasmic sacs are common and some appear to be phagocytosed. At day 8 there are no signs of regeneration and neither dark cells nor swollen cytoplasmic sacs are seen. No signs of intraepithelial inflammation are seen at any time. "Odland"-like granules, which possibly play a role in epithelial desquamation, occur suprabasally in large numbers at all time points. We believe the simultaneous presence of dark cells and phagocytosis at day 6, without signs of inflammation, indicates ongoing apoptosis. Intraepithelial cell loss might explain the discrepancy between an increased proliferation rate and the absence of hyperplasia which has been reported at this time point.

The proliferative response during regeneration of a ringshaped defect in the corneal epithelium.

The aim of the present study was to investigate the regenerative ability of the central corneal epithelium in an in vivo situation, as previous studies have been contradictory regarding the proliferative potential of these cells. Paracentral ringshaped defects were made in rat corneal epithelium, using filter paper soaked in n-heptanol. Cell counts, labelling indices and mitotic rates were measured in sections from the corneal and the adjacent conjunctival epithelium 12 and 28 h after the injury. The cell counts indicated that also central corneal epithelial cells migrate in the early phase of wound healing. No proliferative response was seen in the central corneal epithelium after 12 h. At 28 h both the peripheral and central corneal cells showed an enhanced labelling index, while the mitotic rate only was increased in the periphery. Different cell cycle times and different levels of differentiation of the cell population across the cornea may explain the delayed proliferative response in the central cornea.

The early cell kinetic response during healing of corneal epithelial wounds.

The labeling index and the mitotic rate were measured at 4-hour intervals during the first 24 hours after a central abrasion had been made in the corneal epithelium of six groups of four rats each. The proliferative response was noted in the conjunctival, the limbal, and the corneal epithelium. After 24 hours, the density of epithelial cells was equal throughout the corneal epithelium, but there was only half the normal number of cells. Physiological mechanisms seem strongly to regulate the total number of cells per square unit throughout the healing corneal epithelium, but the nature of these mechanisms is unknown.

Regeneration of the rat corneal epithelium after injury. A cell kinetic study comparing the reaction after abrasions made mechanically and with n-heptanol.

Central corneal epithelial defects with diameter 3.5 mm were made with n-heptanol in the right eyes of rats. Erosions of the same size were made by mechanical scraping in the left eyes of the same animals. All the erosions were covered by epithelium after one day. After one day the mitotic rate and the labelling index were higher in the n-heptanol treated corneas compared to the mechanically abraded ones. Both methods produced similar mitotic rates and labelling indexes after 3 and 12 days. The results from wound healing studies using n-heptanol or mechanical scraping are therefore not entirely comparable because of the different regenerative responses after one day. However, the n-heptanol method is easier to perform and to standardize, and is therefore preferable.

Morphology and proliferation of human corneal epithelium in organ culture.

Organ cultures of central and peripheral human corneal epithelium were maintained for 1 and 2 weeks in Hams F10 medium supplemented with 20% foetal bovine serum, and in medium conditioned by conjunctival epithelial cells. Light microscopy and scanning electron microscopy showed no obvious differences in morphology and survival between central and peripheral explants, or between explants cultured in conditioned and non-conditioned medium. Live cells and areas with confluent growth were seen in all types of explants. The results demonstrate that differences between growth of central and peripheral corneal epithelium in vitro do not necessarily reflect different proliferative potential in vivo. The previously reported lack of survival of central corneal epithelium in culture may reflect an insufficient in vitro system.