Study shows promise for IOL implantation in infants

Undercorrection, intensive patching regimen produce good results, surgeon says.

ByMichela Cimberle

PARIS – Cataract surgery with primary IOL implantation in infants is a controversial procedure. However, today’s refined extracapsular extraction technique with primary IOL implantation provides a good quality of correction with an acceptable rate of postoperative complications, according to Catherine Edelson, MD, of the Fondation Ophtalmologique Rothschild, Paris.

“We conducted a retrospective study on pediatric patients operated in our clinic during their first year of life between 1997 and 2002. Better results were obtained in bilateral cases but also in unilateral cataract patients after intensive patching,” she said here at the meeting of the French Society of Ophthalmology.

Procedure

A total of 76 eyes of 51 patients were included in the study. Twenty-five patients had bilateral cataract, and 26 patients had unilateral cataract. The age of the patients ranged between 1 and 12 months. The surgical technique was designed by Dr. Patrice de Laage de Meux, who operated on many of the patients.

“We performed a standard procedure beginning with a 6-mm reverse corneal incision and an anterior 6-mm capsulorrhexis. The lens was removed by manual aspiration. Posterior capsulotomy and anterior vitrectomy were then performed, and the IOL was implanted. The corneal incision was sealed using single 10-0 nylon sutures at 1-mm distance,” Dr. Edelson explained.

One-piece 811 C PMMA IOLs (Pfizer) were used in all cases. In infants over 3 months of age, the lens was implanted in the bag; sulcus implantation was necessary in younger patients when the bag was smaller than the IOL. The IOL power was calculated with A- and B-scan biometry (SRK II formula) performed under general anesthesia. Dr. Edelson noted that the mean axial length was higher in the group with unilateral cataract, 19.8 mm vs. 16.6 mm in the group with bilateral cataract. Mean calculated IOL power was +38 D, and mean implanted IOL was +26 D.

“To avoid a myopic shift related to ocular growth, we applied an original and simple method of IOL undercorrection. We applied a 40% undercorrection in infants younger than 3 months, a 35% undercorrection between 3 and 6 months and a 30% undercorrection from 6 to 12 months,” Dr. Edelson said.

Postoperative treatment included oral steroids for 10 days and topical steroids four times a day for 1 month. All eyes received intracameral dexamethasone and a subconjunctival injection of gentamicin and dexa-methasone at the end of the surgical procedure.

Glasses and patching were prescribed for 4 weeks after surgery for 80% of the time the infant was awake.

Surgical technique
A reverse corneal incision of 6 mm is created.	An anterior capsulorrhexis of 6 mm is created.	Lens removal is performed by manual aspiration.
A posterior capsulorrhexis is created after lens removal.	A central anterior vitrectomy is performed.	A PMMA IOL is implanted.
The incision is sealed with 10-0 nylon sutures.

Postoperative results

All eyes were examined at 1 day, 1 week, 1 month, 3 months, 6 months and then every 6 months. Evaluation of the anterior segment, fundus, IOP, refractive error and visual acuity (when applicable) was carried out at each visit. Mean follow-up was 35.5 months

“Hyperopia was quite high during the first 6 months and then decreased towards the end of the second year. At 1 month after surgery, it was +5.5 D, and at 2 years it had decreased to 0.7 D. A moderate myopia appeared during the third year postoperatively in spite of our initial undercorrection of the IOL power that was probably not sufficient. At 5 years, mean refraction was –1 D,” Dr. Edelson said.

Visual acuity was recorded at the last examination in April 2003. In the unilateral group, four eyes had a low visual acuity of 20/400 probably because of patching being discontinued too early, according to Dr. Edelson. Five eyes were between 20/200 and 20/80, two eyes were 20/60, one eye was 20/40, and two eyes were 20/30.

In the bilateral group, two eyes were 20/400, three eyes were 20/200, two eyes were 20/100, four eyes were 20/60, three eyes were 20/40, and four eyes were 20/30.

Undercorrection of IOL power and age at the time of surgery

Age in months	1 to 3	3 to 6	6 to 12
Undercorrection in % of the IOL power	40%	35%	30%

Source: Edelson C

“Poor visual gain was observed when patching was discontinued or when a nystagmus coexisted with the cataract. Intensive and prolonged patching seemed to lead to better results in unilateral cases. Comparable results were, however, observed in bilateral cases,” Dr. Edelson pointed out.

Surgical complications included synechiolysis in 10 eyes (13.15%), secondary vitrectomy for opacification of the visual axis in eight eyes (10.52%) and secondary glaucoma in four eyes (5.26%). Severe inflammation occurred in two eyes, resulting in visual loss after the treatment. Strabismus was reported in eight eyes. The reoperation rate was approximately 26%.

“These results make IOL implantation a viable option in the first year of life. A longer follow-up is required to evaluate more precise visual acuity and to report long-term results,” Dr. Edelson said.

For Your Information:

Catherine Edelson, MD, can be reached at Fondation Ophtalmologique Rothschild, 25-29 rue Manin, 75940 Paris Cedex 19; +33-1-48-036922; fax: +33-1-48-036537; e-mail: cedelson@fo-rothschild.fr.