|Year : 1983 | Volume
| Issue : 7 | Page : 941-946
Posterior lensectomy-a study of 193 eyes
AT Rangwala, P Namperumalsamy
Arvind Eye Hospital, Madurai, India
A T Rangwala
Arvind Eye Hospital, Madurai
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Rangwala A T, Namperumalsamy P. Posterior lensectomy-a study of 193 eyes. Indian J Ophthalmol 1983;31, Suppl S1:941-6
|How to cite this URL:|
Rangwala A T, Namperumalsamy P. Posterior lensectomy-a study of 193 eyes. Indian J Ophthalmol [serial online] 1983 [cited 2020 May 26];31, Suppl S1:941-6. Available from: http://www.ijo.in/text.asp?1983/31/7/941/29712
Conventional cataract surgery for varieties of cataracts like congenital, developmental, traumatic, complicated etc. and for displaced lenses has many operative and post-operative complications like vitreous loss,, vitreous incarceration in wound, retained lens matter, corneal oedema, hyphema, shallow anterior chamber, iridocyclitis, after-cataract, epithelial ingrowth,, sub secondary glaucoma with bullous keratopathy and retinal detachment,.
sub Phacoemulsification besides having its own merits has some disadvantages, viz. inability to deal with operative complications like vitreous distrubances which may
accidentally occur in 3 to 22% of eyes,,,,, posterior dislocation of nucleus, late opacification of posterior capsule etc.
Employing the technique for pars plana vitrectomy, Peyman as well as Machemer,
sub conceived a new approach to lens removal through pars plana with very good success. We have, at Arvind Eye Hospital, done so far 193 lensectomies using Peyman's vitreophage.
| MATERIAL & METHODS|| |
The various indications for our series of 193 lensectomies were as follows. These cases were from our Out-Patient Department as well as many were referrals.
Patient Selection and Evaluation
-A careful preoperative examination is an indispensible pre-requisite before taking up a case for lensectomy.
The criteria to be met with are
1. Age-upto the age of 16 years, nucleus is not "formed" and hence lens is expected to be soft. However, we have successfully done lensectomy even up to 35 years if next conditions are fulfilled even at this advanced age.
2. Slit-lamp examination
a) Nucleus-It must be soft enough to be bulged into the suction port of vitreophage and cut by the blade. Sclerosis upto 2+ (on a scale of 4+) is permissible.
0 = Clear nucleus
1+=Nucleus slightly hazy 2+=Beginning brown or gray cobra
tion; no opacity in retroillumination 3+= Definite brown or gray coloration,
slight opacity in retroillumination
4+=Dark brown nucleus, definite
opacity on retroillumination.
b) Cortex and Capsule-If these are calcified and memberanous, the case is excluded for same reasons.
c) Anterior segment examination-to assess the status of vitreous, synechiae etc.
3. Fundus Examination-by indirect ophthaImoscopy was done as far -as possible to rule out incurable fundus pathology.
4. Ultrasonography-to assess fund _ us status in eyes with total lens opacity.
5. On operating table-If knife passed through sclerotomy to lens cannot pierce the nucleus easily but pushes the nucleus forwards or sideways, nucleus is too hard for lensectomy. Here we resorted to conventional surgery.
Majority of patients were operated upon under local anaesthesia, exceptions were children and apprehensive persons. All lensectomies were done with Peyman's vitreophage utilizing guillotine cutting action and operator's finger regulated suction through pars plana apperad.
After adequate exposure, a limbal peritomy was made at 10.30 position. A 4 mm circumferential incision for sclerotomy was made with no.64 Beaver's blade 2.5 mm away from limbus for children upto 10 years of age, 3 to 3.5 mm for young adolescents and 4 to 4.5 mm for adults. (Underlying ciliary body was cauterized well to avoid bleeding). A mattress suture of 5-0 vicryl was passed in sclerotomy lips. A no. 52M Beaver's knife was inserted through sclerotomy anteriorly so as to enter the lens equator. This avoids the injury to base of the vitreous.
After withdrawing the knife, vitreophage was introduced through same tunnel to lens. Preplaced mattress suture was tightened firmly to make sclerotomy leak-proof. Lensectomy began with nucleus first, then cortex and then lastly anterior and posterior capsules were cut and removed. The direction of cutting port was always kept anteriorly: Some amount of anterior vitrectomy invariably accompanied posterior capsulectomy. Peripheral capsule and base of vitreous were carefully avoided. An attempt was always made to maintain a round pupil but when necessary iridectomy was easily done.
Our follow-up duration of 193 lensectomies extends as follows
Upto 6 months 56 eyes
6-12 months 38 eyes
12-24 months 28 eyes
Follow-up not advised due
to incurable fundus pathology 25 eyes
Non-follow up 46 eyes
| Observations and discussions|| |
We have assessed our visual improvements as per modified Peyman and Sanders classification 20. Visual acuty was divided into four levels.
l+ 2+ 3+ 4+
Level I-PL, HM, CF, 1/60
Level 11-2/60 to 5/60
Level 111-6/60 to 6/24
Level-IV-6/18 to 6/6
Visual gain was assessed in scale of 4+
1+-if vision improved in same level
2 2a-if vision improved to next better level
3+-if vision improved by two levels
4+-if vision improved from level I to IV
Visual improvement was assessed as per vision at latest visit by the patient. Visual acuity could not be assessed in some patients because of young age or mental retardation. However in such cases anatomical success was established by creating a clear pupillary area and clear media with normal fundus. Final visual gain depended more on the status of fundus rather than clarity of anterior segment which was achieved in almost all cases, (vide infra). Unimproved vision was either a result of incurable and unrelated fundus pathology, inoperable retinal detachment or amblyopia, not detected preoperatively.
For visual evaluation we should consider only 154 eyes (excluding 39 eyes with unasessed vision from total 193 eyes operated). Thus it is evident that:
1) 116 eyes (75.3%) had gained visually, 92 (59.7%) improving remarkable (3" or 4 ).
2) In congenital and developmental cataract group, 27 eyes (60%) had very good improvement while 9 eyes (20%) improved by 2 -.
3) In traumatic ataract group, 36 eyes (66.6%) gained 3+ or 4+ vision.
4) Results were still better in steroid cataracts and early senile cataracts where all gained 4+ vision improvement.
5) Complicated cataracts and displaced lenses did not do as well as other groups,, but still results are fairly good when their aetiologies are considered. Nearly 50% patients had 3+ or 4+ improvement.
Various complications encountered were as in [Table - 3].
Common anterior segment complications were corneal oedema, -sub iridocyclitis, secondary glaucoma and hyphema. However, incidence of these was much less (11 eyes, 5.6%). Most of these were in traumatic cataract group where any surgery understandably carries higher risks.
Another very important aspect of lensectomy is total avoidance of shallow or flat anterior chamber owing to basic features of surgery. Flat chamber is a major contributory factor for defective post-operative vision. Incidence of this complication is estimated upto 4% in needling and aspiration techniques. Similarly incidence of after-cataract is very low(5 eyes, 2.5%) as compared to estimated 23% eyes developing this after conventional surgery for congenital cataracts.
It will be interesting to analyse cases of retinal detachments.
table depicts that
1) Out of 30, 21 eyes (70%) were detected to have retinal detachment on table. Majority of these belonged to traumatic or complicated groups and could not be diagnosed preoperatively and hence can not be considered a complication of lensectomy procedure per se. Of late however we have been able to avoid doing surgery in such cases by doing a preoperative ultrasonography.
2) In congenital and developmental cataract group, we have not encountered any detached retina so far. The relevant incidence in literature is 2% 8.
3) In traumatic, complicated and dislocated cataracts incidence of post-operative detachment of retina was 4.5% (9 eyes). However, traction band of vitreous to sclerotomy site was not detected in any of these cases. Hence it is safe to assume that these detachments were due to basic pathology of these diseased eyes and not due to lensectomy procedure itself.
4) In steroid and early `Senile' cataracts, no case has developed a retinal detachment in followup period.
The various types of post-operative retinal detachments were as follows
Another important point to consider is that lens nucleus was dislocated in only two patients, first in 53 year old diabetic man when lensectomy had to be unwillingly done while doing vitrectomy and second in 45 year old man with traumatic subluxation. Nucleus could not be removed with vitrophage. While on the other hand in early `senile' cataracts we could successfully do lensectomy even upto 35 years of age since these lenses were found to be `soft' on table. This once again stresses careful selection of patients as outlined.
Advantages of Lensectomy
I. Congenital and Developmental CataractsAdvantages over conventional needling and aspiration are:
1) Lens is removed in toto (except most peripheral part). So incidence of aftercataract is much less.
2) Repeated surgeries are avoided.
3) Since some amount of anterior vitrectomy is invariably done, chances of vitreous disturbances like prolapse, loss, traction, incarceration in the wound are avoided. The incidence of these complications in needling is estimated as 8 to 12%,.One should always remember that vitreous base is not disturbed.
4) Corneal endothelium is not damaged.
II. Traumatic and Complicated CataractsMany of these eyes are complicated by the presence of firm synechiae, capsule remnants, vitreous prolapse, and other vitreous pathology. Lensectomy combined with iridectomy,at synechiae points and vitrectomy offers better treatment with relatively much less anterior segment complications than conventional surgery with its attendant risks like iridocyclitis, hyphema, vitreous loss and traction on retina. Thus lensectomy provides
1 . A clear central optical axis and hence better vision prospects.
2. A clean, one-time procedure.
3. Although long term followup extending over two decades is needed, it hopefully reduces incidence of post operative retinal detachment due to its inherent merits discussed above.
| Summary|| |
193 lensectomies were done through pars plana approach for different causes like congenital, traumatic, complicated, early "senile" cataracts and displaced lenses using Peyman's vitreophage. Good visual results have been obtained in 70% to 50% of patients, depending upon basic aetiology. Incidence of complications is low and authors forEsee an appreciable decrease in post-operative retinal detachments when compared to conservative surgery for the same type of cataract. Advantages of lensectomy over conventional surgery are discussed.
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[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5]