Sir,

Retinitis pigmentosa (RP), in addition to its retinal manifestations, results in abnormalities of the vitreous and crystalline lens. Cataracts are common and following surgery there is a high risk of posterior capsular opacification (PCO). In addition problems with intraocular lens (IOL) tilt and dislocation have been reported following laser capsulotomy. This unusual case serves to highlight the problems that can arise owing to the lens and vitreous abnormalities which occur in RP.

Case report

A 67-year-old farmer with a history of autosomal-dominant RP presented with left visual loss. Twelve months before presentation he had undergone bilateral YAG laser capsulotomies following uncomplicated extracapsular cataract extraction and insertion of one-piece polymethyl methacrylate IOLs 12 years previously. On examination the left visual acuity (VA) was reduced to hand movements and the IOL had dislocated into the inferior vitreous cavity (Figure 1). With contact lens correction the left VA was 6/12 and the patient declined surgical intervention.

Figure 1
figure 1

‘Bone spicule-like’ retinal pigmentation typical of RP with the dislocated IOL visible in the inferior vitreous cavity.

Full size image

Two years later during an episode of left contact lens-related keratitis he was treated with topical antibiotics and cyclopentolate 1%. On review 3 days later the keratitis had resolved but the IOL had migrated into the anterior chamber (AC) (Figure 2a). With spectacle correction VA was 6/18. The patient was delighted to be able to wear spectacles again and declined surgical intervention. Pilocarpine 1% tds was prescribed in order to reduce the chances of the IOL migrating back into the vitreous.

Figure 2
figure 2

(a, left) The IOL has migrated into the AC. (b, right) Following laser iridotomy the pupil block glaucoma has resolved but the cornea remains hazy.

Full size image

One year later he presented with severe left eye pain and decreased vision. On examination the left VA was perception of light and pupil block glaucoma secondary to the IOL was evident. There was iris bombe, IOL-cornea touch, generalised corneal oedema, and an intraocular pressure of 56 mmHg. Following laser peripheral iridotomy the pressure normalised and the bombe and IOL-cornea touch resolved (Figure 2b). Despite surgical removal of the IOL the corneal oedema persisted and the VA remained counting fingers. He is currently being considered for penetrating keratoplasty and secondary IOL.

Comment

The high incidence of PCO following cataract surgery in RP is well described.1, 2 In addition there appears to be a higher rate of lens tilt and dislocation following laser capsulotomy.2, 3 This is thought to be one to a combination of severe anterior capsule fibrosis, zonular weakness, and extensive vitreous degeneration, all of which are associated with RP.3, 4 In this case, vitreous degeneration is also likely to have facilitated migration of the IOL from the vitreous cavity to the AC following pharmacological mydriasis. Following 1 year of conservative management he presented with pupil block glaucoma. Although this resolving following laser iridotomy a combination of the acute attack and IOL-cornea touch has resulted in corneal decompensation.

This case serves to highlight the problems that can arise owing to the lens and vitreous abnormalities which occur in RP. Although similar cases are likely to be rare we would recommend prophylactic laser iridotomy in any case where the IOL has migrated into the AC.