Dr. Mohammad Ihsan Fazal (BMBS, BSc)

Foundation Year Two Doctor, Watford General Hospital, West Hertfordshire Hospitals NHS Trust, UK

Presentation

An 89-year-old female presented to the urgent eye clinic with an 8-month history of blurred vision in the left eye which started in February 2020. Unfortunately, due to the Covid-19 pandemic and England lockdown she did not get seen by an eye specialist until several months later. Eventually she attended her optometrist in July 2020 who referred to the local urgent eye clinic due to reduced visual acuity (right eye: 6/5, left eye: counting fingers).

She could not recall any triggering event for her poor vision and did not report any pain or discomfort. Upon further discussion, she reported short lived episodes of good vision and a large new floater but no other concerns.

Past medical and ocular history

The patient was in remarkably good health with well managed essential hypertension for which she was taking amlodipine 2.5mg. Her past ocular history was more substantive. In 1986 she had suffered a traumatic cataract in her left eye. Interestingly, the clinic notes at the time and the patients own recollection did not identify any traumatic event likely indicating a rarer cause such as infrared or ionising radiation (Tasman and Jaeger, 1997). her visual acuity at that time was R: 6/6 and L:6/9 and so it was decided that cataract surgery should be delayed until visual impairment was more severe. It was only until 10 years later in 1996 that her vision deteriorated, and she underwent extracapsular cataract extraction (ECCE) with intra-ocular lens IOL insertion. It is noteworthy that the operative documentation stated that she had weak zonules in the left eye. The next year in 1997 she underwent YAG capsulotomy to address posterior capsular opacification (PCO) in the left eye. Since then she enjoyed good vision of 6/5 in both eyes with no further ocular problems until now.

Examination

On examination, bilaterally the conjunctivae were white, and the anterior chambers were deep and quiet. The corneas had few superficial epithelial erosions indicative of mild dry eyes. Pupils were equal in size, round and reactive to light. An IOL was present in the right eye but could not be visualised in the left eye raising concern of a posterior IOL dislocation. The patient’s pupils were dilated with topical Tropicamide and 15 minutes later she was examined with a 90D lens. The retina appeared flat, but the peripheral fundus was difficult to visualise. Importantly no IOL could be seen.

Outcome

Given that the patient’s vision was stable and she himself had no concerns she was urgently referred to a local tertiary centre for further assessment and management. Given the ongoing Covid-19 pandemic it is likely her treatment will be delayed. This was communicated to the patient who understood and was thankful for the care she received. Safety netting advice was given, and the referral was made.

Discussion

Posterior IOL dislocation is a complication of cataract surgery which can present many years after the initial procedure with an incidence rate as high as 3% (Gimbel et al., 2005). As the history in this case alludes to, weak zonular fibres are a major cause of IOL dislocation (Wilson, Jaeger and Green, 1987). Late onset dislocation is associated with progressive zonular weakening whereas zonular rupture is seen in early dislocation (Gimbel et al., 2005). Additionally, epithelial proliferation that occurs in PCO can cause strain on the zonules due to the increased capsular weight (Jehan, Mamalis and Crandall, 2001). Furthermore, YAG capsulotomy can lead to an initial IOL subluxation (Davis et al., 2009).

Late IOL dislocation is managed surgically with either repositioning or replacement. In cases such as this where the zonules are severely impaired, the IOL will need to be sutured to the sclera or iris to prevent sequelae (Lorente et al., 2010). Repositioning is favoured as it involves less trauma to the eye and less surgically induced astigmatism due to a smaller incision size (Gimbel et al., 2005).

References

Davis, D., Brubaker, J., Espandar, L., Stringham, J., et al. (2009) ‘Late in-the-bag spontaneous intraocular lens dislocation: evaluation of 86 consecutive cases’, Ophthalmology, 116(4), pp. 664-70. https://doi.org/10.1016/j.ophtha.2008.11.018

Gimbel, H. V., Condon, G. P., Kohnen, T., Olson, R. J., et al. (2005) ‘Late in-the-bag intraocular lens dislocation: incidence, prevention, and management’, J Cataract Refract Surg, 31(11), pp. 2193-204. https://doi.org/10.1016/j.jcrs.2005.06.053

Jehan, F. S., Mamalis, N. and Crandall, A. S. (2001) ‘Spontaneous late dislocation of intraocular lens within the capsular bag in pseudoexfoliation patients’, Ophthalmology, 108(10), pp. 1727-31. https://doi.org/10.1016/s0161-6420(01)00710-2

Lorente, R., de Rojas, V., de Parga, P. V., Moreno, C., et al. (2010) ‘Management of late spontaneous in-the-bag intraocular lens dislocation: retrospective analysis of 45 cases’, Journal of Cataract & Refractive Surgery, 36(8), pp. 1270-1282. https://doi.org/https://doi.org/10.1016/j.jcrs.2010.01.035

Tasman, W. and Jaeger, E. (1997) ‘Traumatic cataract’, in  Duane’s Clinical Ophthalmology.   Lippincott. 4.

Wilson, D. J., Jaeger, M. J. and Green, W. R. (1987) ‘Effects of extracapsular cataract extraction on the lens zonules’, Ophthalmology, 94(5), pp. 467-470. https://doi.org/https://doi.org/10.1016/s0161-6420(87)33423-2