SECONDARY IOL

Secondary intraocular lens (IOL) procedures with modern surgical techniques can provide visual improvements in most patients, although ocular comorbidities double the risk of a poor visual outcome, suggests a long-term retrospective study.

“Despite the risk of postoperative complications, our complex case mix from a tertiary referral population shows that good final visual acuity outcomes can still be safely achieved from carefully planned secondary intraocular lens surgical procedures in challenging eyes,” Jason Ho MBBS reported at the XXXII Congress of the ESCRS in London.

The study reviewed 197 eyes of 172 consecutive patients who underwent secondary IOL procedures at Moorfields Hospital from 2003-2012 and a mean follow-up of around five years, said Dr Ho, an ophthalmology resident at Moorfields Eye Hospital and Academic Clinical Fellow at the Institute of Ophthalmology, University College London.

The most common procedures were secondary IOL insertion for aphakia, which included 76 anterior chamber IOL implantations, 65 sulcus IOL implantations, and three secondary in-the-bag implantations. In addition, 39 eyes underwent IOL exchange and 14 underwent IOL repositioning (23.5
per cent).

Dr Ho noted that approximately two-thirds of the patients had significant ocular comorbidities, including penetrating intraocular trauma, intraocular foreign body cases. Nearly half of patients had undergone complicated cataract surgery with complications. In addition, 14 per cent had already undergone previous vitreoretinal interventions for retinal detachments occurring either before or after cataract surgery or as a result of complicated phaco.

Nonetheless, despite the two-thirds comorbidity rate, two-thirds of patients achieved vision of 6/12 or better. The median best corrected visual acuity (BCVA) improved from 6/60 preoperatively to 6/16 postoperatively among those undergoing IOL exchange or repositioning, and from 6/69 to 6/13 among those receiving the lenses for aphakia or other reasons. Around half of those with final BCVA worse than 6/12 had a contributing ocular comorbidity.

Legacy aphakes

Among patients undergoing the procedures for aphakia, typically three months after removal of the crystalline lens, those who received posterior chamber implants achieved slightly better final acuity than those with anterior chamber implants, although the difference did not reach statistical significance, Dr Ho said.

The “legacy” aphakes who had undergone intracapsular cataract surgery in the 1980s had significant gains in vision following the secondary lens implantation, with mean visual acuity improving from 6/21 preoperatively to 6/15 postoperatively (p=0.006).

Visual acuity was also significantly improved for those who underwent secondary lens implantation to correct aphakia resulting from complicated phaco procedures, with a mean final value of 6/15, compared to 6/280 preoperatively (p=0.0001). Among those 36 patients who underwent the secondary procedures for refractive reasons, the significant improvement in mean spherical equivalent, from 3.23D to 0.96D (p=0.02) was not matched by a statistically significant improvement in mean visual acuity (6/32 preoperatively to 6/12 postoperatively, p=0.466). Their indications for the surgery included anisometropia, astigmatism and refractive surprises, and most received sulcus piggyback lenses.

The overall complication rate was 29 per cent. Early complications included uveitis in 16 eyes, cystoid macular oedema in 10 eyes, elevated IOP in eight eyes, hyphaema in three eyes and wound healing problems in two eyes. The late complications included glaucoma in 10 eyes, nine IOL dislocations, five cases of PCO and four cases of corneal decompensation. Among the nine eyes with IOL dislocations, there were seven with significant comorbidities, including four eyes for which penetrating trauma was the original indication for the secondary IOL.

“While these procedures do significantly improve vision in our complex cohort of patients, two-thirds of our cases had significant comorbidities and it is important to counsel carefully that the presence of ocular comorbidity doubles the risk of a poor visual outcome,” Dr Ho added.

* Dr Ho has asked us to credit Mr Alex Ionides and Mr Badrul Hussain, consultants at Moorfields Eye Hospital, as senior authors of the study

Jason Ho: Jason.ho@moorfields.nhs.uk