Intra-ocular lens implantation after vitreous loss.
Vitreous loss is a dreaded complication of cataract surgery, especially so with IOL implant which then may have to be abandoned. Thirty three cases of IOL implants, either anterior chamber or posterior chamber, after vitreous loss done in the past 3 years were studied. Of these, 18 (55%) had a final visual acuity of 6/18 or better and none was worse than 6/60. The postoperative complications and findings and a review of literature are discussed.
Though the incidence of vitreous loss has reduced dramatically with modern microsurgical extra-capsular cataract extraction techniques and adequate pre-operative precautions to obtain a soft eye, it still remains far from negligible.
A decade ago, vitreous loss was considered to be a definite contraindication for IOL implant by most surgeons,. Though the situation has changed, many still hesitate from implanting on IOL after vitreous loss for fear of worsening the complications of the vitreous loss. A majority of those who proceed with implantation despite the vitreous loss, use an anterior chamber-IOL. Posterior chamber-IOLs are sometimes used, mostly with trans-scleral fixation. However, there are now reports of complications like late endophthalmitis associated with these.
Two hundred and ninety nine consecutive IOL implantations done in the past 3 years at our centre were reviewed of which 33 cases with vitreous loss (11%) were analysed. Most of these were done at the inception of the IOL implant programme in our hospital.
Thirty-three patients who underwent IOL implantation after vitreous loss at out centre over a period of 3 years were evaluated retrospectively and prospectively. The postoperative evaluation included visual acuity with spectacle correction, refraction, fundus and slit-lamp examination, tonometry and FFA where indicated.
The pre-operative vision was PL PR in 21 (63%) cases, upto FA IM in 9 (27%) cases and better than that in only 3 (10%) cases [Table - 3].
The associated systemic illnesses present were two cases each of hypertension, diabetes mellitus and tuberculosis and one of bronchial asthma.
All surgeries were done under operating microscope. Vitreous loss occurred in all after delivery of the nucleus while doing irrigation/aspiration (I/A). Significant cortex was left behind in 5 (15%) cases when I/A became impossible due to vitreous in AC. An anterior vitrectomy was performed by: (1) aspiration with 18 gauge needle - 21 (64%) cases, (2) sponge and scissor technique - 10 (30%) and (3) automated vitrector - 2 (6%).
Care was taken to achieve a concave vitreous face, round pupil and an iris, anterior chamber and wound free of vitreous strands,,. The anterior chamber was then formed with an air bubble.
In 10 (30%) cases where the rent in the posterior capsule was central with a rim of intact capsule in the periphery a Sinskey PCIOL was inserted. The optic thus served to plug the gap in the posterior capsule. If the rent was larger or in the periphery with part of capsular rim lost and angle fixated flexible AC-IOL (CILCO multiflex of optiflex) was used. There were 23 (70%) such cases.
Wound was closed with interrupted 3/5/7 sutures depending on the size of the wound using 8-0 virgin silk in all but 3 cases where 90 nylon was utilised.
Of the 33 cases we studied 25 (75%) were males. Twenty-seven patients (82%) were above the age of 40 years. [Table - 1]. Nineteen cases (57%) presented with a senile mature cataract and 11 (33%) with a senile immature one. Two were traumatic cataracts, both in male patients and one was congenital again a male child, 10 years of age [Table - 2].
Seven of the 10 (70%) patients who received a PC IOL implant had a final visual acuity (VA) of 6/18 or better; for the ACIOL's the figure for this visual acuity stood at 11 out of 23 (48%), None of the cases had a visual acuity worse than 6/60 when last seen. [Table - 3].
The post-operative complication or CME (cystoid macular oedema) was the cause of poor VA in 6 eyes with an AC-IOL (18% of the total) but in none of those with a PC-IOL. Another 6 eyes (18%) in this series were found to have ARMI) (age related macular degeneration) responsible for their reduced VA. No cause could be ascertained in 4 cases.
The most common post-operative complications were mild keratitis and iritis, which resolved within one week.
Two of AC implants developed hyphaema. One of these had a small blood clot on the upper anterior surface of the lens near the wound. The other was a diabetic who had a streak of blood in the AC when seen a follow up on the 6th post-operative day. Both resolved spontaneously within a week.
The intra-ocular pressure was raised in two (6%) eyes with an AC- IOL. A PBHI had not been done in both. One of these was controlled medically. The other required a PBHI to relieve the pupillary blick with internal iris proplapse. This second procedure was done on the 10th post-operative day.
None of the cases showed evidence of cornea1 decompensation and none developed a retinal detachment during the follow up. [Table - 4].
One PC implant had to be removed on the second post-operative day when it was discovered to be posteriorly dislocated. It was replaced with an optiflex CILCO AC-IOL. The final VA in this patient was 6/24.
Vitreous loss during cataract surgery can lead to poor visual results alongwith other complications.
However, as Alpar and Fechner have stated, IOL implant can safely be done following vitreous loss provided a generous and careful anterior vitrectomy is performed.
Most of the reported series of IOL implants after vitreous loss have used the AC lenses.
Jaffe reported VA of 20/40 (or 6/12 approximately) and better in 80% of his series with an incidence of complications not significantly higher than with routine IOL implantation. However, the Binkborst iris-clip lens he used, is now obsolete.
In Mazzoeco's series of 38 cases, (35 AC-IOL's and 3 PC-IOL's) 27 (71%) had VA 20/40 or better. Nine cases (23%) developed CME and 10 (26%) had post-operative raised intra ocular pressure controlled medically . Both concluded that the procedure was safe in the hands of an experienced surgeon.
In a series of 24 cases reported by Pearson et al 18 patients (75%) had VA 20/40 or better while the remaining 6 (25%) had VA 20/200 (6/60) approximately or worse. There were 5 cases (21%) of cystoid macular edema CME, 3 of glaucoma and 3 of uveitis. Three cases showed evidence of corneal decompensation and another 3 developed retinal detachment. They concluded that the complications of vitreous loss and AC-IOL's may be acting in concert in some and advocated caution in IOL implantation after vitreous loss.
Spigelman et al reported a series of 26 patients 7 (20 PC- IOL, 6 AC-IOL) where all patients with PC-IOL and 4 with AC-IOL had VA 20/40 (approx. 6/12) or better. One case had retinal detachment. They concluded that a meticulous anterior vitrectomy was essential for good results and risk of retinal detachment is higher than otherwise.
In the present series, 18 of the 33 patients i.e. 55% had a VA of 6/18 or better and none was worse than 6/60, Totally 70% of those with a PC-IOL and 48% of the AC-IOLs had a VA 6/18 or better. Cystid macular oedema occurred in 6 (18%) cases - all of them with AC-IOLs. this significant difference in the results with PC and AC-IOL should be considered against the background or the basis on which the choice of the lens was made.
AC-IOLs were used for eyes with a large or peripheral rent in posterior capsule. The capsular support available was minimal, I/A was sometimes incomplete with resultant iridocyclitis. The vitreous disturbance was also greater due to the larger rent in posterior capsule, some I/A done in presence of vitreous in AC and a greater loss of vitreous volume. This may have been responsible for greater incidence of CME thus a reduced VA. However, no firm conclusions can be drawn from this series alone due to the small size of the two groups.
In the 2 cases of raised intraocular pressure (6%) failure to do a PBHI was clearly responsible in one. It is therefore prudent to do a PBHI in all cases especially with AC-IOL.
There were no cases of corneal decompensation due to the surgery, nor those of retinal detachment, thought it is too soon to comment on the latter.
Age related macular degenerations were found in significant 18% of cases (6 eyes). Unfortunately, it can neither be diagnosed pre-operatively in the presence of advanced cataract, nor treated satisfactorily later.
The lopsided 25:8 male : female ratio in this series when the incidence of cataract is the same in both sexes reflects perhaps the lower socio-economic status and illiteracy of the patients attending our clinic and their social attitudes. The very high incidence (90%) of mature of advanced immature cataracts can also be explained against the same background. A lack of understanding in many of these patients for achieving the exact cylindrical correction is also responsible for some of the poor visual results.
In conclusion IOL implant can safely be done after vitreous loss with reasonable visual results. An adequate and careful anterior vitrectomy helps in keeping the post-operative complications low. A PC-IOL can be chosen for the implant if adequate posterior capsular support is present in the periphery despite the loss of vitreous. If this posterior capsular rim is absent in any part of the circumference it would be safer to use an AC-IOL.