Haptic breakage following neonatal IOL implantation in a nonhuman primate model

What we have learned from the Infant Aphakia Treatment Study: The 49th Annual Frank D. Costenbader Lecture

Unilateral congenital cataracts lead to deprivation amblyopia, which can be severe. Until the 1970s, they were believed to be always associated with poor visual outcomes. However, advances in our understanding of the plasticity of the infant brain and the development of better surgical techniques allowed good visual outcomes to be obtained in a few of these patients. The Infant Aphakia Treatment Study (IATS) was conducted to provide empirical evidence regarding the best type of optical correction to be used following surgical extraction of the cataract. Specifically, infants were randomly assigned to either be left aphakic and to wear contact lenses or an intraocular lens (IOL) was implanted and the residual refractive error was corrected with spectacles. The study found that good visual acuity and stereopsis could be achieved in some patients in both treatment groups. Early cataract surgery, consistent optical correction and part-time patching of the fellow eye are important elements needed to achieve good visual outcomes. However, excess patching of the fellow eye may interfere with the development of stereopsis. More adverse events occurred after IOL implantation, particularly visual axis opacification, compared with the infants who were left aphakic. Glaucoma-related adverse events occurred in 40% of eyes after a 10-year follow-up and were not associated with IOL implantation. Further research is needed to increase the percentage of children with unilateral congenital cataracts who achieve good visual outcomes.

Fracture of a polyimide-elastimide posterior chamber intraocular lens following blunt orbital trauma

PURPOSE

Fracture of a three-piece polyimide-elastimide intraocular lens at the optic-haptic junction following blunt trauma is a possible complication after cataract surgery. We report a case of an isolated posterior chamber intraocular lens fracture caused by direct ocular blunt trauma.

CASE

A 51-year-old patient underwent blunt orbital trauma caused by a raw chicken egg that was thrown at him, as he was walking. The posterior chamber intraocular lens was found in the anterior chamber, with a broken optic-haptic junction. The intraocular lens was exchanged, followed by iris fixation and pupilloplasty, with satisfactory postoperative anatomical and optical outcomes.

DISCUSSION

The three-piece polyimide-elastimide intraocular lens was fractured at the optic-haptic junction. Although the fractured intraocular lens surface had a regular appearance, it has been previously reported that the polyimide haptic's durability is probably inferior to that of polymethylmethacrylate. Therefore, it is highly susceptible to shear stress induced by a blunt trauma.

CONCLUSION

To our knowledge, this is an uncommon report of an implanted posterior chamber polyimide-elastimide intraocular lens fracture following blunt orbital trauma. Intraocular lens exchange and fixation had successful optical and anatomical results.

Spontaneous Fracture of an Implanted Posterior Chamber Intraocular Lens

Purpose

Spontaneous fracture of an intraocular lens (IOL) haptic is a rare complication of cataract surgery. The authors report a case of spontaneous fracture of an implanted posterior chamber IOL.

Case

Five years ago, a 12-year-old patient underwent linear lens extraction, posterior capsulotomy, and anterior vitrectomy due to traumatic cataract and received a polymethyl methacrylate (PMMA) biconvex posterior chamber IOL implanted in ciliary sulcus. Five years later, IOL optic was found in anterior chamber with its haptics broken from the optic-haptic junction.

Discussion

The broken haptic was examined with scanning electron microscopy. The fracture site of the haptic was on the optic-haptic junction. The fractured surface had a regular appearance.

Conclusions

To our knowledge, this is the fourth report of spontaneous fracture of an implanted posterior chamber IOL.

Traumatic fracture of posterior chamber intraocular lens

An 18-year-old man developed a fracture in a single-piece polymethylmethacrylate posterior chamber (PC) intraocular lens (IOL) at the optic-haptic junction with dislocation of the IOL into the anterior chamber after a fist injury to the eye. The dislocated IOL was explanted and replaced with another PC IOL.

Cataracts in children

Bilateral congenital cataract is the most common cause of treatable childhood blindness. Nuclear cataract is usually present at birth and is nonprogressive, whereas lamellar cataract usually develops later and is progressive. Surgery must be performed promptly in cases with dense congenital cataract; if nystagmus has developed, the amblyopia is irreversible. A treatment regimen based on surgery within 2 months of birth combined with prompt optical correction of the aphakia and aggressive occlusion therapy with frequent follow-up has been successful in unilateral and bilateral cases. Both anterior and posterior capsulorhexes are performed in most children. Intraocular lens implantation can be performed safely in children older than 1 year. Anterior dry vitrectomy is recommended in preschool children to avoid after-cataract. Opacification of the visual axis is the most common complication of cataract surgery in children. Secondary glaucoma is the most sight-threatening complication and is common if surgery is performed early. Life-long follow-up is essential in these cases.

After-cataract in children having cataract surgery with or without anterior vitrectomy implanted with a single-piece AcrySof IOL

PURPOSE

To evaluate whether cataract surgery in children should be performed with anterior vitrectomy and to examine the properties of the AcrySof SA30AL intraocular lens (IOL) in the pediatric eye.

SETTING

Filatov Institute, Odessa, Ukraine.

METHODS

Cataract surgery was performed in 66 children aged 3 to 15 years. They were randomized to surgery with or without anterior vitrectomy. All eyes were implanted with the single-piece AcrySof SA30AL IOL (Alcon). During the study, the patients who needed surgery for after-cataract had a second surgical procedure. Two years after surgery, the surgical method was evaluated using exact logistic regression. Also, the Evaluation of Posterior Capsule Opacification (EPCO) score was compared between the patients who had surgery for after-cataract and the patients who did not need this. The presence of posterior synechias and centration of the IOL were assessed.

RESULTS

Children in the younger age group (</=62 months at surgery) had surgery for after-cataract more often than children in the older age group (P<.01). Patients who did not receive an anterior vitrectomy had surgery for after-cataract more often (P<.01). Age at surgery and whether an anterior vitrectomy was performed did not significantly affect the EPCO score. The patients who had surgery for after-cataract had a significantly higher EPCO score (P<.001). The IOL remained centered in all eyes; no eye developed posterior synechias.

CONCLUSIONS

This prospective study shows that cataract surgery with anterior vitrectomy is advantageous in younger patients concerning after-cataract formation. The AcrySof SA30AL maintains good centration, produces minimal inflammation, and is well tolerated in the pediatric eye.

Corneal decompensation and graft failure secondary to a broken posterior chamber poly(methyl methacrylate) intraocular lens haptic

A 66-year-old man developed an unexplained corneal decompensation 7 years after extracapsular cataract extraction and implantation of a single-piece poly(methyl methacrylate) (PMMA) posterior chamber intraocular lens (IOL). He had penetrating keratoplasty (PKP). Two years later, he developed corneal graft failure secondary to an IOL haptic fragment in the anterior chamber angle. The patient had a repeat corneal graft and IOL exchange. The broken haptic was examined with scanning electron microscopy. The findings were consistent with late fracture of the haptic within the capsular bag, which was presumably weakened by an improper implantation technique. Fracture of a PMMA haptic should be suspected as a cause of corneal decompensation and corneal graft failure after cataract surgery. This case emphasizes the importance of safe implantation techniques.

Infantile lensectomy and intraocular lens implantation with long-term follow-up in a monkey model

PURPOSE

To report the long-term clinical and histopathologic findings in infant monkeys following a lensectomy and intraocular lens (IOL) implantation using two different surgical techniques.

METHODS

A lensectomy and IOL implantation was performed on the right eye of 10 infant monkeys. A posterior capsulotomy was performed using a limbal approach in 5 monkeys (Group 1), and a pars plana approach in 5 other monkeys (Group 2). The residual refractive error in the pseudophakic eye was then corrected with a contact lens and the fellow eye was occluded for 70% of the daylight hours. The monkeys were then examined at regular intervals for 2 to 4 years. Visual acuity was assessed using operant testing and sweep visual evoked potentials (VEPs). At the end of the study, the pseudophakic eyes were studied histopathologically.

RESULTS

The only complications that required reoperation were diaphanous fibrin membranes on the lens optic (n=10) and lens reproliferation into the pupillary space (n=5). The visual outcome was similar in Groups 1 and 2, with better acuities in the phakic eyes compared with the pseudophakic eyes. A higher percentage of both haptics were found in the capsular bag for the monkeys in Group 2 (n=3) than in Group 1 (n=1).

CONCLUSIONS

Although haptic placement was superior using a pars plana approach to perform the primary posterior capsulotomy, no clinically discernable difference was noted in IOL centration between the monkeys undergoing a limbal versus a pars plana posterior capsulotomy and no difference was noted in the visual outcome.

Intraocular lens implantation in infant monkeys: clinical and histopathological findings

PURPOSE

To determine the long-term effects of intraocular lens (IOL) implantation in infant monkey eyes.

SETTING

Yerkes Regional Primate Research Center, Emory University School of Medicine, Atlanta, Georgia, USA.

METHODS

A 30.00 diopter (D), all-poly(methyl methacrylate) IOL with an overall diameter of 10.0 mm was implanted in the right eye of 11 infant monkeys. Seven monkeys developed postoperative complications and were not followed on a long-term basis. However, 4 monkeys were followed clinically for 4 1/2 years, after which their pseudophakic eyes were examined histopathologically.

RESULTS

The final refractive error in the four pseudophakic eyes with long-term follow-up ranged from -4.75 to +0.75 D. Three of the four eyes had a Soemmering's ring. Only one haptic was in the capsular bag. whereas five had eroded into the iris root/ciliary body. The corneas and posterior segments of the eyes were normal.

CONCLUSION

Two-thirds of the eyes having neonatal IOL implantation experienced significant postoperative complications. Haptic location was suboptimal in all four eyes followed for 4 1/2 years. The diameter of the IOLs implanted in these eyes was probably too large. Some of these complications might have been averted by implanting an IOL with a smaller diameter.

Infantile cataracts

Cataracts are one of the most treatable causes of visual impairment during infancy. Recent epidemiological studies have shown that they have a prevalence of 1.2 to 6.0 cases per 10,000 infants. The morphology of infantile cataracts can be helpful in establishing their etiology and prognosis. Early surgery and optical correction have resulted in an improved outcome for infants with either unilateral or bilateral cataracts. While contact lenses continue to be the standard means of optically correcting an infant's eyes after cataract surgery, intraocular lenses are gaining in popularity as an alternative means of optically correcting these eyes. Post-operative complications occur more commonly after infantile than adult cataract surgery and many of these complications do not develop until years later. As a result, it is critical that children be followed closely on a long term basis after infantile cataract surgery.