Long-term changes in corneal endothelium following intraocular lens implantation

Long-term (≥10 years) results of corneal endothelial cell loss after cataract surgery

OBJECTIVE

To investigate the extent of long-term corneal endothelial loss after uneventful cataract surgery and the factors associated with decreases in corneal endothelial cell density (ECD).

DESIGN

Retrospective case series.

PARTICIPANTS

Patients who had undergone uncomplicated cataract surgery.

METHODS

This study comprised 81 eyes of 48 patients who had undergone cataract surgery >10 years previously by a single surgeon with the same intraocular lens and visited the outpatient clinic between January 2014 and February 2017. Long-term (≥10 years) changes in visual outcome and ECD after uncomplicated cataract surgery were evaluated. To analyze factors correlated with endothelial cell loss, preoperative biometric variables, including cataract grade, anterior chamber depth, axial length, and postoperative corneal edema, were evaluated.

RESULTS

The mean ± SD preoperative and long-term postoperative ECD was 2793 ± 351.09 and 2148 ± 478.38 cells/mm², respectively. The mean follow-up period was 11.08 ± 1.06 years and 10-year ECD loss rate was 20.62 ± 13.63%. Preoperative nuclear firmness was most statistically correlated with 10-year ECD loss (β-coefficient 0.394 [95% CI 3.402-9.448]; p < 0.001). The degree of postoperative corneal edema was also a significant predictive factor of 10-year ECD loss after cataract surgery (β-coefficient 0.378 [95% CI 2.854-8.358]; p = 0.002).

CONCLUSION

Preoperative nuclear firmness and postoperative corneal edema were predictors of long-term (≥10 years) endothelial cell loss and severe endothelial cell loss after cataract surgery. It is important to remember that eyes with increased nuclear firmness have a significantly higher risk of long-term enhanced ECL.

Implantation of posterior chamber phakic intraocular lens for myopia and hyperopia - long-term clinical outcomes

PURPOSE

To evaluate long-term refractive outcomes of implantable collamer lens (ICL) implantation and late postoperative complications.

METHODS

We assessed outcomes of patients who underwent ICL implantation (type ICM V4 for myopia, ICH V3 for hyperopia, TICM V4 for astigmatism) in our department between 1998 and 2013. It comprised 62 eyes (40 myopic and 22 hyperopic). The average follow-up period was 10.5 years. We evaluated: uncorrected and best-corrected visual acuity (UCVA and BCVA), spherical equivalent (SE), ICL vault, endothelial cell density and late postoperative complications.

RESULTS

In myopes, the average UCVA was 1.0±0.37 and BCVA 1.18±0.38, in hyperopes 0.78±0.19 and 1.14±0.18, respectively. The average SE in myopes, whose target refraction was emmetropia, was -0.6±0.83 Dsf, in hyperopes +0.73±0.93. Central ICL vault was 206.16μm±105.94, (range 10-427) in myopes, 195.5μm±109.09, (range 20-404) in hyperopes. The most common late postoperative complication was cataract formation. Three myopic eyes (7.5%) developed symptomatic anterior subcapsular opacities with loss of at least two lines of BCVA. Cataract significantly affecting visual acuity occurred in 5 myopic eyes (12.5%) and 2 hyperopic eyes (9.09%). In these eyes, ICL removal and cataract surgery was performed.

CONCLUSIONS

In our experience, ICL implantation in moderate and high ametropia was effective and relatively safe. The most common late complication was cataract formation. This complication can be managed effectively surgically with good refractive outcomes without loss of BCVA.

A Comparison of Clinical Outcomes of Dislocated Intraocular Lens Fixation between In Situ Refixation and Conventional Exchange Technique Combined with Vitrectomy

Purpose. To evaluate surgical efficacy of in situ refixation technique for dislocated posterior chamber intraocular lens (PCIOL). Methods. This was a single-center retrospective case series. 34 patients (34 eyes) who underwent sclera fixation for dislocated IOLs combined with vitrectomy were studied. Of 34 eyes, 17 eyes underwent IOL exchange and the other 17 eyes underwent in situ refixation. Results. Mean follow-up period was 6 months. Mean logMAR best corrected visual acuity (BCVA) was not significantly different between the groups 6 months after surgery (0.10 ± 0.03 in the IOL exchange group and 0.10 ± 0.05 in the refixation group; p = 0.065). Surgically induced astigmatism (SIA) was significantly lower in the refixation group (0.79 ± 0.41) than in the IOL exchange group (1.29 ± 0.46) (p = 0.004) at 3 months, which persisted to 6 months (1.13 ± 0.18 in the IOL exchange group and 0.74 ± 0.11 in the refixation group; p = 0.006). Postoperative complications occurred in 3 eyes in the IOL exchange group (17.6%) and 2 eyes in the refixation group (11.8%). However, all of the patients were well managed without additional surgery. Conclusion. The in situ refixation technique should be preferentially considered if surgery is indicated since it seemed to produce a sustained less SIA compared to IOL exchange.

Corneal endothelium--past, present, and future

OBJECTIVE

To review the history of the growth in knowledge about the corneal endothelium.

METHODS

Publications concerning the corneal endothelium were reviewed.

RESULTS

Highpoints in the growth of knowledge about the corneal endothelium include discovery of barrier and pump functions, specular microscopy, reduction in surgical trauma, corneal preservation, and future advances.

CONCLUSIONS

The highpoints in the history of the growth in knowledge about the corneal endothelium were elucidated.

Histopathologic study of changes occurring in eyes with intraocular lens implantation: autopsy eyes, enucleated eyes and corneal buttons

The clinicopathologic findings in 17 eyes which were surgically enucleated or removed at autopsy as well as the histopathology of 72 corneal buttons removed from eyes with intraocular lenses are described. In four of five autopsy eyes the intraocular lens was well tolerated; however, in all cases, changes related to the pseudophakos were found. In seven of 12 surgically enucleated eyes, postsurgical bacterial or fungal endophthalmitis had developed. On histopathological examination, one eye revealed clinically unsuspected endophthalmitis phacoanaphylactica after extracapsular cataract extraction and intraocular lens implantation. In two cases, choroidal melanoma became evident after cataract extraction and insertion of a pseudophakos. In both cases preoperative ultrasonography was limited to A-scan axial measurements. The 72 corneal buttons were removed from patients with pseudophakic bullous keratopathy; histologically the most striking findings were guttata-like changes in 50% of the specimens and retrocorneal membranes in 13.9% of the specimens.

Artisan Phakic Iris Claw Intraocular Lens for High Primary and Secondary Hyperopia

PURPOSE

To evaluate the efficacy, predictability, and safety of the Artisan iris claw phakic intraocular lens for the correction of high primary and secondary hyperopia.

METHODS

Fifty-seven eyes were divided into two groups: 29 eyes had primary hyperopia (mean refraction 6.06 +/- 1.26 D, and 28 eyes had secondary hyperopia, (mean refraction 5.88 +/- 1.88 D) induced or residual following a previous corneal refractive procedure. Consecutive implantation of the Artisan iris claw phakic intraocular lens was performed. Main outcome measures recorded were BSCVA, UCVA, refraction, and astigmatic change, intraocular inflammation, and endothelial cell loss.

RESULTS

Primary hyperopic group: Preoperatively, mean UCVA was 0.4 +/- 0.7 and mean BSCVA was 0.2 +/- 0.6. After implantation, mean UCVA was 0.3 +/- 0.6 and BSCVA was 0.1 +/- 0.6. Mean cycloplegic residual spherical refractive error after surgery was 0.10 +/- 0.57 D (range -1 to +2 D). Mean surgically induced astigmatism was 1.48 +/- 0.89 D. Safety index was 1.11. Efficacy index was 0.83. Secondary hyperopic group: Preoperatively, mean UCVA was 0.5 +/- 0.7 and mean BSCVA was 0.2 +/- 0.6. Postoperatively, mean UCVA was 0.4 +/- 0.7 and mean BSCVA was 0.2 +/- 0.6. Mean cycloplegic residual spherical refractive error was 0.55 +/- 1.49 D. Mean surgically induced astigmatism was 1.85 +/- 1.19 D. Safety index was 1.05. Efficacy index was 0.7. Postoperative iridocyclitis was observed in one eye (3.4%) in the primary group and in three eyes (10.7%) in the secondary group. Overall corneal endothelial cell loss at 1 year of follow-up was 9.4%.

CONCLUSION

The Artisan iris claw phakic intraocular lens was reasonably safe and predictable for correcting high hyperopia.

Long-term evaluation of endothelial cell loss after phacoemulsification

PURPOSE

To check whether three months' follow-up is sufficient to determine endothelial cell loss after cataract surgery and whether this value depends on preoperative central endothelial cell density.

METHODS

A two-year prospective assessment of central endothelial cell density was done in 60 eyes after phacoemulsification. In 30 eyes a 3.5 mm corneal incision closed with a single crossed suture was made, and the other 30 had a 3.5 mm scleral tunnel no-stitch incision. Central endothelial cell density was measured before surgery and 1, 3, 6 months and 2 years after.

RESULTS

The mean rate of endothelial cell loss even two years after surgery was significantly higher than the physiological rate, amounting to 0.9% per year. There was no correlation between preoperative central endothelial cell density and postoperative cell loss.

CONCLUSIONS

Even two years' follow-up is not sufficient to establish the total endothelial cell loss after cataract surgery. The amount of cell loss does not depend on the preoperative density.

Safety of posterior chamber phakic intraocular lenses for the correction of high myopia: anterior segment changes after posterior chamber phakic intraocular lens implantation

OBJECTIVE

To assess the safety of posterior chamber phakic intraocular lens (PCPIOL) implantation in patients with high myopia.

DESIGN

Prospective, noncomparative, interventional case series.

PARTICIPANTS

Twenty eyes of 10 patients were included.

INTERVENTION

Staar Collamer Implantable Contact Lens PCPIOLs were implanted for the correction of high myopia.

MAIN OUTCOME MEASURES

Intra- and postoperative complications were recorded. Specular microscopy, lens fluorophotometry, laser flare-meter, and ultrasound biomicroscopy were performed before surgery and at different stages of the follow-up period to evaluate endothelial cell density, crystalline lens transmittance, aqueous flare, and anatomic relations of the implanted lenses with the other structures of the anterior segment.

RESULTS

There were no intraoperative complications. One patient experienced pupillary entrapment by the lens in the immediate postoperative period, which was resolved without incident. Pigmentary dispersion or cataracts did not appear during the postoperative period. All the lenses remained correctly centered, and no patient reported night halos or glare. Anterior chamber depth showed a statistically significant reduction, between 9% and 12%. Central endothelial density was significantly decreased after surgery. The percentages of cell loss after 3, 6, 12, 18, and 24 months were 4.41%, 4.83%, 5.17%, 5.46%, and 6.57%, respectively. Aqueous flare increased by 49.19% in the first postoperative month in relation to preoperative values. Afterward, it decreased and then remained above preoperative values for the entire follow-up period (33.76% at month 3, 27.81% at month 6, 27.65% at month 12, 23.39% at month 18, and 27.27% at month 24). Crystalline lens transmittance decreased by 0.72% at month 3, by 1.44% at month 6, by 1.95% at month 12, by 2.25% at month 18, and by 2.24% at month 24. Finally, by ultrasound biomicroscopy it was observed that the PCPIOL and the crystalline lens were in contact on the peripheral level in 12 patients (60%) and in the center in another three patients (15%) during at least one checkup. In all the patients, contact between the PCPIOL and the posterior iris surface could be observed.

CONCLUSIONS

Posterior chamber phakic IOL implantation for the surgical correction of high myopia is a safe procedure with regard to immediate visual and refractive results. The short-term clinical benefit and lack of immediate surgical complications are impressive. However, the increase in flare, the endothelial cell loss, the decrease in crystalline lens transmittance, and the iris-PCPIOL and crystalline lens-PCPIOL contact are findings that suggest caution regarding the long-term safety of this lens implant.

A comparison of visual results and complications in eyes with posterior chamber intraocular lens dislocation treated with pars plana vitrectomy and lens repositioning or lens exchange

PURPOSE

To compare the visual results and the postoperative complications in eyes with posterior chamber intraocular lens (PCIOL) dislocation that underwent pars plana vitrectomy with lens repositioning with eyes that underwent pars plana vitrectomy with lens exchange.

DESIGN

Nonrandomized consecutive comparative case series.

PARTICIPANTS

Fifty-nine eyes (27 right eyes and 32 left eyes) of 56 subjects (28 women and 28 men) ranging in age from 59 to 90 years. Mean follow-up was 34 months.

METHODS

A comparison of the best-corrected preoperative visual acuities, final visual acuities, and postoperative complications in subjects with dislocated PCIOLs that underwent pars plana vitrectomy. Logarithm of the minimum angle of resolution (LogMAR)-converted visual acuities were used for comparison. Categorical data were analyzed by Fisher's exact test, and population means were compared by a pooled Student's t test.

MAIN OUTCOME MEASURES

Final mean visual acuities, change in mean visual acuities, and postoperative complications.

RESULTS

For all 59 eyes the mean preoperative visual acuity was 20/152, and the mean final visual acuity was 20/48. Final visual results were similar between the eyes that underwent lens repositioning (20/55) and the eyes that underwent lens exchange (20/43; P = 0.19). Final visual results were also similar between the eyes that underwent lens exchange with sutured PCIOL placement (20/51) and the eyes that underwent lens exchange with anterior chamber intraocular lens (ACIOL) placement (20/38; P = 0.26). Final mean visual acuity in eyes that received an ACIOL (20/38) was better than in eyes that underwent repositioning of the dislocated lens into the ciliary sulcus (20/65; P = 0.01). The mean increase in visual acuities was greater for eyes with ACIOL placement compared with eyes with sutured PCIOL placement (P = 0.01). For all eyes, final visual results were unaffected by a concurrent diagnosis of age-related macular degeneration (20/52; P: = 0.71), glaucoma (20/48; P = 0.95), or postoperative cystoid macular edema (20/55; P = 0.45). Final visual acuities were significantly worse in eyes with a detectable preoperative afferent pupillary defect (20/200; P<0.0001). Postoperative retinal detachments developed in 4 of 29 eyes (14%) that underwent lens repositioning and in 2 of 30 eyes (7%) that had lens exchange (P = 0.42). Postoperative lens subluxations occurred in 6 of 29 eyes (21%) that underwent lens repositioning and in 1 of 30 eyes (3%) that underwent lens exchange (P = 0.05).

CONCLUSIONS

The final visual results in eyes with dislocated PCIOLs that underwent pars plana vitrectomy with lens repositioning were similar to the visual results obtained in eyes that underwent pars plana vitrectomy with lens exchange. For eyes that underwent lens exchange, final visual results in eyes that received an ACIOL were similar to the visual results obtained in eyes that received a PCIOL; however, eyes with an ACIOL showed a greater increase in mean visual acuity. Eyes with a preoperative afferent pupillary defect had worse final visual results.

Endothelial study of iris-claw phakic lens: four year follow-up

PURPOSE

To study quantitative and morphometric endothelial changes in phakic eyes implanted with the Worst iris-claw lens to correct high myopia.

SETTING

Department of Ophthalmology, University Hospital "La Fe", Valencia, Spain.

MATERIAL AND METHODS

This retrospective study involved 111 phakic eyes (73 patients) implanted with the Worst iris-claw lens. Noncontact specular microscopy and computer-assisted analysis was performed preoperatively and 6 months and 1, 2, 3, and 4 years postoperatively.

RESULTS

The mean cell loss was 3.85% at 6 months, 6.59% at 1 year, 9.22% at 2 years, 11.68% at 3 years, and 13.42% at 4 years. At 2 years, the hexagonality and coefficient variation in cell size were close to the preoperative levels. No major complications were seen; early postoperative corneal touch required intraocular lens (IOL) removal in 1 case (0.9%). Four eyes (3.6%) needed a reoperation because of poor IOL fixation (2 eyes), traumatic subluxation of the IOL (1 eye), and miscalculation of the IOL power (1 eye).

CONCLUSIONS

Although there was a slight progressive cell loss after IOL implantation, the morphometric changes recovered and were close to the preoperative levels. This suggests that endothelial damage occurred primarily during the surgical procedure.

Posterior Chamber Phakic Intraocular Lens for Myopia of -8 to -19 Diopters

PURPOSE

To examine the efficacy, predictability, stability, and safety of posterior chamber phakic intraocular lens (IOL) implantation in patients with extreme myopia.

METHODS

We analyzed the results of 124 eyes that received a posterior chamber hydrogel collagen plate phakic IOL (Staar Collamer Implantable Contact Lens, ICL) for the correction of their myopia. The target postoperative spherical equivalent refraction was emmetropia. Mean follow-up was 11 months (range 1 to 36 mo).

RESULTS

The mean preoperative spherical equivalent refraction was -13.38 +/- 2.23 D (range, -8.50 to -18.63 D). Mean postoperative spherical equivalent refraction at last examination was -0.78 +/- 0.87 D (range, +1.63 to -3.50 D), with 69% (86 eyes) within +/-1.00 D and 44% (55 eyes) within +/-0.50 D of emmetropia. The refraction remained stable with a statistically insignificant change (p > 0.05 at each interval) during follow-up. A gain of two or more lines of spectacle-corrected visual acuity was seen in 36% (45 eyes) at last examination. One eye (0.8%) lost two or more lines of spectacle-corrected visual acuity from a retinal detachment.

CONCLUSION

Posterior chamber phakic IOL implantation with the Staar Collamer plate lens is an effective and safe method for reducing or correcting myopia between -8 and -19 D. Gains in spectacle-corrected visual acuity were common, and results suggested good refractive stability. Improvements in phakic IOL power calculation formulas are needed to improve the predictability of refractive outcome.

Intraocular lens complications requiring removal or exchange

Intraocular lens (IOL)-related complications are caused primarily by mechanical trauma, inflammatory or infectious complications, or optical problems. Complications may occur at the time of surgery or be the result of an ongoing postoperative process. Mechanical and inflammatory injury may produce corneal decompensation, cystoid macular edema, hyphema, uveitis, and glaucoma, causing reduced vision and in some cases chronic pain. Optical problems may be due to a wrong power of the IOL or to postoperative decentration or dislocation of the lens. Ophthalmologists should be aware of the indications for IOL removal or exchange in those patients who have ongoing IOL-induced injury or impairment. Removal or exchange of an IOL frequently involves a complex decision-making process and is often associated with immense technical challenge. Various medical and surgical treatments may be tried to correct IOL problems before the decision is made to remove or exchange the lens.

Endothelial changes in phakic eyes with anterior chamber intraocular lenses to correct high myopia

PURPOSE

To evaluate the long-term endothelial cell loss after implantation of Worst-Fechner and Baikoff ZB5M anterior chamber intraocular lenses.

SETTING

Jiménez-Díaz Foundation and San Carlos University Hospital, Madrid, Spain.

METHODS

Preoperative and serial postoperative specular microscopy was performed on 30 eyes that had a Worst-Fechner lens and on 28 eyes that had a Baikoff ZB5M lens to correct high myopia. A video specular microscope adapted to an image analysis system was used to analyze the endothelium for cell density. Follow-up was 24 months.

RESULTS

In the Worst-Fechner lens group, postoperative endothelial cell density was significantly lower than preoperative density at all times (P < .001). Endothelial cell loss was 7.26% at 3 months, 10.64% at 6 months, 13.00% at 12 months, and 17.60% at 24 months. In the Baikoff ZB5M lens group, postoperative cell density was also significantly lower than preoperative density at all times (P < .001). It was 7.50% at 3 months, 10.94% at 6 months, 12.33% at 12 months, and 12.30% at 24 months. Cell loss did not stabilize between 1 and 2 years after surgery in the Worst-Fechner group (P = .047). However, no additional cell loss was noted during this period in the Baikoff ZB5M group (P = .968). Endothelial cell densities in the two groups did not differ during the first year. However, 2 years after surgery, cell density in the Worst-Fechner group was significantly lower than it was in the ZB5M group (P = .048).

CONCLUSIONS

Endothelial cell loss during the first year was similar in eyes with Worst-Fechner and Baikoff ZB5M lenses; however, at 2 years after surgery, endothelial cell loss was higher in eyes with Worst-Fechner lenses than it was in eyes with Baikoff ZB5M lenses.

Long term changes in human corneal endothelium following toxic endothelial cell destruction: a specular microscopic and fluorophotometric study

AIMS

To investigate the long term relation between corneal thickness, endothelial morphometric variables, and endothelial permeability in patients with endothelial cell counts under 900 cells/mm2 as a result of endothelial cell destruction after cataract surgery.

METHODS

Eighteen patients developed the so called toxic endothelial cell destruction (TECD) syndrome following routine cataract surgery because of the intracameral injection of a toxic detergent residue. Ten patients with a mean (SEM) initial cell loss of 72% (2%) were followed for 4 years. Data were obtained at 6 months and 4 years postoperatively and compared between TECD eyes and contralateral control eyes.

RESULTS

Mean (SEM) endothelial cell density of the TECD eyes increased from 642 (41) cells/mm2 to 849 (50) cells/mm2 at 4 years postoperatively (p = 0.005). There was no difference in coefficient of variation or percentage hexagonals between 6 months and 4 years postoperatively. Mean (SD) corneal thickness of the TECD eyes and control eyes was similar, 0.51 (0.02) mm and 0.49 (0.01) mm, respectively (p = 0.65). Mean (SD) endothelial permeability was also similar for TECD eyes and control eyes (4.3 (0.9) x 10(-4) cm/min and 4.4 (0.6) x 10(-4) cm/min, respectively (p = 0.57). There was no correlation between endothelial cell density, coefficient of variation, or percentage of hexagonal cells and endothelial permeability in the TECD eyes. In three patients a permanent corneal decompensation occurred.

CONCLUSIONS

Four years after TECD corneal endothelial wound healing is stable and the barrier function has been restored.

Long-term endothelial cell loss and breakdown of the blood-aqueous barrier in cataract surgery

Progressive endothelial cell loss and endothelial cell loss induced at the time of surgery occurs in all eyes with rigid anterior chamber intraocular lenses (IOLs). Eyes with surgical tuck or late ovaling of the pupil following surgery have greater yearly rates of cell loss than eyes that have no complications. This progressive loss may be related to chronic uveitis from iris chafing by the implant or to direct mechanical damage to the corneal endothelium. We have demonstrated that fluorophotometry shows chronic damage to the blood-aqueous barrier in all eyes with rigid anterior chamber IOLs, but this does not correlate with the degree of endothelial cell loss. Our results suggest there is damage to the blood-aqueous barrier and to the corneal endothelium, but the damage to the latter influences progressive endothelial cell loss.

Experimental evaluation of a phakic anterior chamber implant in a primate model. Part II. Pathology

Anterior chamber intraocular lenses were implanted in 50 phakic primate eyes and followed by serial histopathology for two years. Significant observations included corneal endothelial alterations, haptic erosion into and encapsulation by peripheral iris and ciliary body, and chronic low grade inflammation.

Experimental evaluation of a phakic anterior chamber implant in a primate model. Part I. Clinical observations

Anterior chamber intraocular lenses were implanted in phakic cynomolgus monkey eyes and followed clinically over two years. Significant observations included erosion and/or uveal envelopment of the haptic and a decrease in endothelial cell counts. There was good positional stability, no significant inflammation, initial ocular hypotension that returned to normal intraocular pressure, and no evidence of cataracts or cystoid macular edema.

Corneal endothelial changes after posterior chamber intraocular lens implantation in patients with or without diabetes mellitus

We examined 96 patients (111 eyes) who underwent extracapsular cataract extraction with the implantation of a posterior chamber intraocular lens. Of 96 patients 24 (29 eyes) with non-insulin-dependent diabetes mellitus had no or simple retinopathy; 72 patients (82 eyes) served as non-diabetic controls. The central corneas of all subjects were photographed by a specular microscope preoperatively and three, six, and 12 months postoperatively. No significant differences in the endothelial cell density, coefficient of variation, or cell loss were noted between diabetic patients and age matched non-diabetic subjects during the observation period.

The corneal endothelium

The endothelium is a monolayer of cells on the posterior corneal surface that transports water from the stroma into the anterior chamber. This movement of water counters a natural tendency for the stroma to swell and is necessary to maintain a transparent cornea. Embryologic studies, in particular the demonstration of the derivation of the endothelium from the neural crest, have provided insight into the factors that govern the response of this tissue to disease. In some species the endothelium can regenerate after injury, but in man cellular enlargement is the main mechanism of repair after cell loss. A clinical estimate of endothelial cell density and function is provided by specular microscopy, fluorophotometry and pachymetry. In this paper we review the development, structure and function of the corneal endothelium, and then consider the pathological processes that can affect this tissue.

Graft failure after penetrating keratoplasty

Despite the improving results that have been noted with penetrating keratoplasty, graft failure remains a significant problem. The causes of graft failure are quite varied. Primary donor failure, surgical complications, intraocular lens complications, persistent epithelial defects, allograft rejection, infection, glaucoma, trauma, and recurrences of primary corneal dystrophies are common etiologies. In this article, a critical review of the available literature concerned with the factors influencing the many causes of graft failure and their management is provided.

Complications of anterior chamber lens implants and their effects on the endothelium

A five-year follow-up study of 186 eyes which were subject to intracapsular cataract extraction and rigid anterior chamber lens implantation is reported. Ninety-two per cent of cases achieved a visual acuity of 6/12 or better. Serial corneal endothelial cell counts were performed. In 37 pairs of eyes the median difference in operative endothelial cell loss between the operated and un-operated eyes was -7.3% (95% Confidence Interval from -8.7 to -6.1%). Iris tuck occurred in 22.0% and late 'iris ovalling' developed in a further 15.6% of eyes. The median operative endothelial cell loss for those eyes with iris tuck was -9.7% and this was significantly higher than that of eyes with no long-term complications (median loss = -7.3%). The median operative endothelial cell loss for those eyes which developed late ovalling was -8.0% and this was not significantly greater than that of the eyes with no long-term complications (p = 0.745). There was a progressive median endothelial cell loss for all operated eyes and this progressive cell loss was significantly greater for those eyes with iris tuck when compared with those with no complications (p = 0.045).

Results of penetrating keratoplasty for pseudophakic bullous keratopathy with the exchange of an intraocular lens

We report on 29 consecutive patients with pseudophakic bullous keratopathy who underwent in one eye penetrating keratoplasty with an exchange of the original intraocular lens for a Pearce tripod posterior chamber lens, and who were available for a follow up of at least 12 months. The average interval between cataract extraction with lens implantation and the appearance of bullous keratopathy was five and a half years (range 10 months to 16 years). The mean follow-up period after penetrating keratoplasty was 36 months (range 12 to 56 months). The corneal graft remained clear in 22 (76%) eyes. One year after the operation 45% of the eyes had a vision of 20/40 or better, and 20% had visual acuities between 20/40 and 20/100. The remaining 31% had a vision of 20/100 or less (one unknown). Nine eyes (31%) had cystoid macular oedema or macular degeneration. 45% of the eyes had a refraction within approximately 2 dioptres of emmetropia. In patients with pseudophakic corneal oedema we continue to exchange the intraocular lens by a Pearce tripod posterior chamber lens sutured to the iris when it is necessary to remove the lens.

Protective effect of the anterior lens capsule during extracapsular cataract extraction. Part II. Preliminary results of clinical study

In a clinical study, 61 patients underwent phacoemulsification with subsequent intraocular lens (IOL) implantation. An intercapsular capsulotomy with phacoemulsification was performed on 23 patients and a can opener capsulotomy with phacoemulsification on 38 patients. Wide-field specular microscopy was performed preoperatively and postoperatively on all of the eyes in the study. The cell counts were not divulged to the surgeon before or at the time of surgery. Average endothelial cell loss for the intercapsular technique was 3.9%; with the can opener technique, the average cell loss was 10.1%. This difference was statistically significant (P less than 0.01). Positive correlations between endothelial cell loss relating to ultrasound time and/or the hardness of the cataract existed for the can opener group only (P less than 0.01). These results demonstrate that a protective effect is provided by the presence of the anterior lens capsule during lens substance removal.

Long-term changes of the corneal endothelium following intracapsular cataract extraction with implantation of open-loop anterior chamber lenses

The central corneal endothelium of a consecutive group of 158 patients with senile cataract was examined before intracapsular cataract extraction with implantation of an open-loop anterior chamber lens and 6, 12 and 48 months after surgery. Corneal endothelial morphometry was performed using an automated digital image analysis system. After 6 months of follow-up, there was an average loss of 10.8% in central corneal endothelial cell density, which increased to 14.8% after 12 months and 18.8% after 48 months. The early post-operative endothelial cell loss was correlated significantly with a decrease of cell pattern stability and polymegathism (P less than 0.0001). There was also a significant correlation between the continuous post-operative cell loss and the simultaneous changes of pattern stability and polymegathism and the age at the time of surgery (P less than 0.05).

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.

Evaluation of endothelial cell function with anterior segment fluorophotometry in pseudophakic patients

Determining fluorescein permeability of the endothelial cell layer provides information on the endothelial cell barrier. Following topical application of fluorescein, the time dependent change of its concentration in the corneal stroma and in the aqueous humor yields the transfer coefficient (Kc) of the corneal endothelium. Measurements with a fluorophotometer resulted in a Kc of 0.002 minute to 0.005 minute for normal eyes. Patients with corneal barrier dysfunction (cornea guttata, Fuch's dystrophy) showed an increased Kc of 0.006 minute to 0.013 minute. Up to five years postoperatively, none of the patients investigated after phacoemulsification and posterior chamber lens implantation showed a disturbance in the endothelial cell barrier function.

Comparison of the effect of polymethylmethacrylate and silicone intraocular lenses on rabbit corneal endothelium in vitro

An in vitro comparison of corneal endothelial damage caused by polymethylmethacrylate and by silicone intraocular lenses was made. Endothelial damage was assessed by vital staining of corneal endothelium immediately following direct contact with an intraocular lens. Silicone lenses produced less damage than polymethylmethacrylate lenses. The difference could be attributed to a specific type of damage-membrane stripping-seen only after contact with polymethylmethacrylate lenses.

Pigment dispersion syndrome in pseudophakic corneal transplants

We observed the pigment dispersion syndrome in two patients after keratoplasty with posterior chamber intraocular lenses. In addition to a heavily pigmented trabecular mesh-work and iris transilluminating defects, an inferior linear pigmented endothelial line was seen in both patients. One patient developed glaucoma, which was well controlled with medication. Pigment dispersion syndrome in patients with penetrating keratoplasty should not be confused with an allograft reaction but should alert the transplant surgeon that a different process is occurring.

Long term observations on an anterior chamber Ridley intraocular lens

In 1965 the patient, aged 6, sustained a perforating eye injury which was repaired and a traumatic cataract was aspirated within five weeks. Five years later a Ridley Mk 2 A/C intraocular lens was inserted. Several episodes of blunt trauma occurred over a three year period following this procedure. This paper reports the clinical, corneal pachometric and specular microscopic findings of both traumatized and normal fellow eyes 18 years after the initial incident. The corneal endothelial mosaic of the traumatized right eye was very irregular in the vicinity of the initial site of perforation. These marked variations in cell size and shape were less apparent at peripheral corneal areas. The estimated cell loss to the traumatized eye was in the region of 74% although in spite of this corneal function was maintained. The effects of trauma on the corneal endothelium are discussed and a brief review of the literature presented.

Intraocular lenses: a histopathologic study of eyes, ocular tissues, and intraocular lenses obtained surgically

Eyes, ocular tissues, and intraocular lenses obtained surgically from 179 eyes of 177 patients were studied to determine the histopathologic features of complications related to anterior chamber, iris-fixation, iridocapsular, and posterior chamber lens implantation.

Histopathological findings in necropsy eyes with intraocular lenses

The histopathological findings in five post-mortem eyes with anterior chamber and iris fixation intraocular lenses (IOLS) are discussed. The interval between lens insertion and death ranged from 3 1/2 to 52 months. Clinically the lenses were well tolerated and the surgery was considered to be successful. In one case a vitrectomy was required. Prominent histopathological features included reduced corneal endothelium (five cases), central cornea guttata (one case), dislocation of an anterior chamber IOL (one case), abnormalities of the filtration angle (five cases), non-granulomatous iritis (two cases), and iris atrophy and erosion (five cases).

Secondary intraocular lens implantation during or after corneal transplantation

An analysis of the effects of secondary intraocular lens implantation on the clinical results of corneal transplantation in four groups of eyes showed that the mean visual acuity in 27 eyes undergoing intraocular lens implant at the time of aphakic keratoplasty and in 12 eyes undergoing intraocular lens implantation after corneal transplant was approximately 20/40; the visual acuity in 24 eyes undergoing intraocular lens exchange at the time of transplant for pseudophakic bullous keratopathy and in 18 eyes undergoing intraocular lens removal at the time of transplant for pseudophakic bullous keratopathy was poorer. The techniques used were simple and did not increase the incidence of transplant complications. Intraocular lens implantation combined with corneal transplants should be considered in aphakic eyes requiring corneal transplants, in eyes requiring simultaneous cataract extraction and corneal transplants, and in eyes in which cataracts have developed after corneal transplant.

Regional specular microscopy of endothelial cell loss after intracapsular cataract extraction: a preliminary report

In a group of 10 patients (12 eyes) undergoing intracapsular cataract extraction, corneal endothelial cell loss was serially investigated by means of regional specular microscopy. Prevoperatively there were no significant regional differences in the endothelial cell density. Two weeks after surgery, the superior endothelium alone showed a significant cell loss (15.6%). Whereas, a definite endothelial cell loss occurred in each region of the cornea one month after surgery. The cell loss was greater in the superior (22.8%) and lower in the inferior (4.7%), respectively, when compared to that seen in the central cornea (9.6%). In each region, cell loss continued 3 months postsoperatively, but no significant cell loss occurred thereafter. These results suggest that the entire endothelial cell population may participate in the healing of the damage associated with intracapsular cataract extraction and that regional specular microscopy can be of help for detailed evaluation of such a damage.

A comparison of ciliary sulcus and capsular bag fixation of posterior chamber intraocular lenses

We compare indications, advantages, and disadvantages of ciliary sulcus and lens capsular bag (lens capsular sac) fixation of posterior chamber intraocular lenses (IOLs). Our findings suggest that, whenever possible, it is efficacious to implant the loops of posterior chamber IOLs within the capsular bag. This positions the lens optic and the supporting loops in the natural anatomical position, sequestered from highly vascular uveal tissue and the blood aqueous barrier. This should minimize the potential for complications that may be associated with iris-ciliary body contact. Considering the rapid increase in the number of implantations of IOLs now being performed (approximately 700,000 per year in the United States alone), a possible reduction of even 1% in clinically significant complications would make this effort worthwhile. Widespread application of in-the-bag implantation is predicated on the assumption that the surgeon is proficient with this procedure and that careful follow-up of patients does not reveal any significantly increased incidence of lens dislocation due to zonular rupture.

Results of penetrating keratoplasty for pseudophakic corneal edema with retention of intraocular lens

We reviewed the records of 26 consecutive patients undergoing penetrating keratoplasty for pseudophakic corneal edema in which the original intraocular lens was retained. The average interval between lens implantation and penetrating keratoplasty was 31.5 months. Follow-up after keratoplasty ranged from 11 to 59 months, with an average of 24.5 months. Six patients had anterior chamber lenses; sixteen, iris or iridocapsular lenses; and four, posterior chamber lenses. A vitrectomy was performed in 14 (54%) patients. Of the 21 patients with clear grafts (80%), 8 (38%) had vision of 20/40 or better while 7 (33%) had acuities of 20/200 or worse. Visual acuity of 20/40 or better was attained by 3 of 4 (75%) patients with posterior chamber lenses but only 3 of 16 (19%) patients with iris-supported lenses. Cystoid macular edema was the principal cause of decreased acuity in 12 of the 13 patients with clear grafts and acuity less than 20/40. Angiographic confirmation was obtained in 7 of 12 patients. Overall, the results are similar to those reported for pseudophakic keratoplasty with intraocular lens removal. No adverse effect of retaining a securely fixated intraocular lens was demonstrated.

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.

Results of penetrating keratoplasty for aphakic and pseudophakic bullous keratopathy

We retrospectively studied 61 consecutive cases of penetrating keratoplasty performed for aphakic bullous keratopathy or pseudophakic bullous keratopathy. After keratoplasty, the mean visual acuities of both groups of patients improved significantly from preoperative levels (P less than .0001). One year after keratoplasty, 18 eyes had visual acuities of 20/40 or better. Twelve of the 24 eyes followed up for at least two years after surgery had visual acuities of 20/40 or better. The mean visual acuities for the eyes with aphakic bullous keratopathy and the eyes with pseudophakic bullous keratopathy were not significantly different at either one or two years after keratoplasty. Cystoid macular edema (11 eyes) and glaucoma (12 eyes) were the most common causes of visual acuities worse than 20/40. There were no significant differences in the incidences of these complications in the group with aphakic bullous keratopathy and in the group with pseudophakic bullous keratopathy. Intraocular lens removal did not significantly affect either visual acuity or macular complications after keratoplasty.

Corneal endothelial loss with new intraocular lenses

When we compared the effect of a hydrogel intraocular lens on the corneal endothelium of rabbits to the damage produced by uncoated methylmethacrylate intraocular lenses and methylmethacrylate lenses coated with sodium hyaluronate or methylcellulose, we found that the endothelial damage produced by the hydrogel lenses in a standard 0.25 mm2 of contact was 3.6%. This value was not significantly different from that for the control corneas (0.4%). Uncoated methylmethacrylate lenses caused 62% endothelial loss but coating them with sodium hyaluronate or methylcellulose reduced the loss to 27% and 57% respectively. The results suggested that a hydrogel intraocular lens produces minimal endothelial damage and that coating a methylmethacrylate lens with sodium hyaluronate or methylcellulose does not provide reliable endothelial protection.

Changes of the corneal endothelium following intracapsular cataract extraction with implantation of semiflexible anterior chamber lenses. I. Results of the early post-operative period

A consecutive group of 103 patients with senile cataract underwent intracapsular cataract extraction and implantation of a semiflexible anterior chamber lens. After 6 month of follow-up, there was an average decrease of 20% +/- 15% in central corneal endothelial cell density and an average vertical disparity of 32% +/- 20% between central and superior endothelial areas. The endothelial cell loss was not correlated with pre-operative cell density. There was a positive correlation between age and cell loss and between age and vertical disparity. Findings in eyes with cornea guttata did not differ significantly from those without guttata. Anterior vitrectomy did not increase endothelial cell loss significantly. Maintenance of a deep anterior chamber by pre-operative oculopression or by instillation of Na-hyaluranate had no significantly different effect on the corneal endothelial cell loss.