|Year : 1982 | Volume
| Issue : 5 | Page : 409-426
Paras plan, surgery
Sankara Nethralaya, A Unit of Medical Research Foundation, 18, College Road, Madras-600006, India
S S Badrinath
Nethralaya a unit of Medical Research Foundation 18, College Road, Madras
|How to cite this article:|
Badrinath S S. Paras plan, surgery. Indian J Ophthalmol 1982;30:409-26
I consider myself extremely fortunate for having been selected to deliver the Major S.C. Dutta oration for 1981.
I stand before you as the recipient of the highest honour the all India ophthalmological society bestows on a young ophthalmologist. Truly speaking, I consider that this unique honour and the great tribute paid to me today -entirely belongs to the institution "Sankara Nethralaya". I wish to express on this occasion to one and all of the hard working and dedicated professional colleagues, the fellows as well as the consultants, my special and sincere acknowledgement of their extreme devotion and co-operation and to the able administration, particularly the Board of Management of the Medical Research Foundation, my eternal indebtedness fur having made my dream come true.
Major S.C. Dutta, born in Calcutta in the year 1890, graduated from the Calcutta Medical College in 1913. He specialised in ophthalmology at Moorfields in England and University of Vienna, in Austria. He was a special invitee at the International Congress of Ophthalmology held in London in 1950 to read his research paper on 'Epidemic Dropsy'. He was the President of our illustrious All India Ophthalmological society in 1953-54. A devoted Rotarian, his life was full of achievements in various fields besides ophthalmology - a very inspiring one, particularly to youngsters like myself.
In the late sixties, while 1 was in Boston, with Dr. Charles L. Schepens, I was most fortunate to see the array of development in vitreous surgery, vitreous scissors, balloon, vitreous forceps and the vitreous substitutes such as hyaluronic acid, collagen, silicone oil, etc. But it was here in Madurai in India that I was exposed to the revolution in vitreous surgery of the seventies by Dr. Gholam Peyman, Professor of ophthalmology, University of Illinois Eye and Ear Infirmary. It was a thrilling, unforgettable and a memorable event in my life to watch the disc emerge out of the clouds of vitreous haze. Fortunately, my mentor to closed paras plana surgery, Dr. Gholam Peyman is physically present here and may I take this opportunity to thank him from the bottom of my heart for having introduced me to this `soul thrilling' ultimate in ophthalmic surgery-the vitreous surgery. To Dr. Mohanuas M Kini and Dr. Peter H. Morse who are also present here today to watch my progress, my special salutations.
| Applied anatomy|| |
Paras plana a part of the ciliary body is located posterior to paras plicata of the ciliary body and anterior to the ora serrata, the anterior limit of the retina.
Vitreous base, is a 2 mm. broad band wherein the vitreous is strongly adherent to the adjacent retina and paras plana; it straddles on either side of the ora serrata, around 360° are of the globe.
The Long posterior ciliary artery and the nerve are normally located at the 3 and 9 0' clock horizontal meridians.
The incisions for entry into the paras plana are made 3.5 mm. from limbus in any meridian except 3 - 9 O'clock zones to avoid injury to long post ciliary artery and nerves.
Frans liumination is an extremely useful adjunct - vessel free illuminated area between paras plicata and ora serrata is chosen for making sclerotomy entry sites into paras plana [Figure - 1].
| Instrumentation|| |
1. Operating microscope.
2. Neutralising contact lens. 3. Ocutome unit model 800A.
4. Fibre optic light source with endoilluminator.
5. Infusion system.
6. Wilson's lens fragmentor.
7. Wilson's 50 gauge infusion canula. 8. Charles' flute needle.
1. Operating Microscope
The Carl Zeiss OPMI-7F is used at Sankar. Nethralaya. The foot pedal allows zoom focussing, thus a variable magnification from 6x to 24x is available. Minimum magnification allows larger field size and greater depth of focus and is used during greater part of the surgery. When working very close to retina, greater magnification may be utilised for short periods of time for higher magnification and better identification on structures during surgery.
The X-Y coupling allows lateral movement of microscopic observation system through remote control foot switch. When the bimanuaI paras plana surgery is being carried out in the extreme periphery by rotating the eye ball in the desired position, the microscope observation system is shifted accordingly with remote control foot switch The working distance is 150 mm. The fibre optic light source of the microscope system is available as
(i) coaxial with observation system used during most surgery including anterior vitrectomy.
(ii) Paraxial illumination-a source of general illumination.
(iii) Slit illumination - particularly useful in lensectomy and mebranectomy for final inspection of the cleared pupillary area to make doubly sure that thin capsule or membrane remnants are not left behind in the optical pathway.
The microscope also has a beam splitter with attachments for
(a) Observer's tube (for assistants).
(b) 35 mm.still camera.
(c) 16 mm. movie camera.
(d) Closed circuit T.V. camera.
2. Neutralising Contact Lens [Figure - 2]
Lumalens is a -50.00 D piano concave lens the diameter being 12 mm. Made of plastic resin, this semi hard contact lens stands repeated autoclave sterilisation. For visualisation of posterior vitreous and the retina, the concave side of the lens is applied over the moist cornea. By pressing the centre the air is expelled between the two surfaces and the lens is held in situ even when the eye is turned in different directions with the two instruments inside the eye during bimanual surgery. Observation through luma lens results in minification and larger field size, both advantageous to the surgeon. Richards, "Machemer contact lens" held in position by the assistant has continuous irrigation of the lens cornea interface. It can be shifted from one position to another.
3. Ocutome Unit Model 800 a [Figure - 3]
It hase got two major components. (a) Control unit. (b) Ocutome probe.
(a) The control unit provides controlled source of pressure and suction to operate the probe. It has the following important parts:
(i) Suction gauge : This is aneroid type and can be varied between 0" to 15" of mercury as required.
(ii) Cutting rate knob : This is for adjusting the rate between 50 to 400 strokes per minute.
(iii) Suction bottle: For collection of debris.
(iv) Foot switch p dal : For pure suction or suction with cutting. Each can be operated independent of the other.
(b) The ocutome probe has got three main parts [Figure - 4].
(i) Base : It has provision for connecting the & ebris tube and the actuator tube through which the probe is connected to the control unit
(ii) Barrel : It is used to hold the instrument and connect the base with the needle.
(iii) Needle : This goes inside the eye. It is a 20 gauge size. Cutting port is situated on one side of tip of the needle.
Through this the tissue is aspirated and cut by guillotine action of the cutter inside the needle. The port opening can be varied from 0 to 0.9 mm., in 0.1 mm. stage for control over bite size.
The opening port is always in open position when not working. So no incarceration of tissue takes place.
4. Illumination system [Figure - 5]
Illumination system consists of light generation system, fibre optic cables and accessories. The conical beam illuminator is used for internal illumination for posterior vitrectomy. It is introduced into the eye through a separate sclerotomy, in paras plana. The transcorneal illuminator is used to select this paras plana sclerotomy entry site.
5. Infusion system [Figure - 6]
For infuson a separate sclerotomy is made and infusion canula (20 gauge ) is fixed to sclera with mattress suture. This is connected to infusion bottle with the help of tubings and intravenous set.
Infusion can be combined with the ocutome probe by using a Charles' infusion sleeve eliminating ones sclerotomy.
Infusion is by gravity feed, the intraocular pressure is controlled by adjusting the height of the infusion bottle. The rate of infusion is regulated with the help of a metal pinch clamp.
6. Willson's Lens Fragmentor [Figure - 7]
This pneumatically activated instrument provides to and fro jack hammer type of movement of a solid rod at the tip of the probe needle. It is similar to Peyman's Fragmentor, but unlike the Peyman's instrument it does not provide the infusion and suction.
The maximum projection of the inner oscillating road is 1.5 mm. from the tip of the probe needle. The tip of the probe needle is rounded off to reduce the sharp angular features and to facilitate easy entry through scleral incision.
The to and fro movement is made possible by the movements of a piston activated by compressed air from a compressor located in the main console of Vijaya Sukut machine.
The advantage of this instrument is that it could be used in conjunction with the ocutome system and utilises the same sized entry site for introduction into the eye.
7. Wilson 20 Gauge Infusion Canula [Figure - 8]
This is an indigenously made 20 gauge needle with a blunt rounded offend. It is bent to 140°sub approximately 3/4 from the tip. At the hub end of the needle where the intravenous tubings are connected, a hexagonal aluminium sleeve is provided. This acts as a handle for easy and comfortable manipulation of the infusion canula. This comes handy in anterior segment surgery for directing flow fluid.
8. Charles' flute needle [Figure - 8]
This is a 20 gauge blunt rounded off needle with a handle over its hub end. There is a hole over the handle which communicates with the lumen of the needle. The hole is situated at a convenient distance over the handle and can be closed or opened with fingertip movement.
This is used to extrude the contents of the eye ball, e.g., a pool of blood or subretinal fluid under controlled conditions by the pressure obtained with infusion in a closed cavity. Fluid gas exchange can also be done with this.
Indications [Table - 1]
They are many but only few major indications make the subject of this study as shown in [Table - 1]. This also excludes surgery performed for some indications with vitreophage and or Vijaya Sukut.
Anterior segment indications are for clearing pupillary area while posterior segment indications are for better visualization of fundus for improving functional results.
| Vitrectomy work up|| |
This includes thorough Ophthalmological examination of both eyes including ultrasonography.
This done to diagnose presence of rubeosis cataract, glaucoma or abnormal vitreoretinal relationship pre-operatively so that surgery can be planned pre-operatively.
Rubeosis can best be detected by examining the iris with cobalt blue filter on slit lamp after injecting the fluorescein intravenously. Even early cataract interferes with proper visualzation while doing posterior vitrectomy and so when it is existing pre-operatively, lens extraction should be combined with paras plana surgery.
Pre-operative management [Table - 2]
This is described in brief in [Table - 2]. 1 prefers to use Inj. Ampicillin 500 mgm. 1 m. one hour before surgery. This gives a high blood concentration at the time of surgery. Maximum and sustained pupillary dilatation is a must in vitrectomy. This can be achieved with alternate use of homatropine and phenylephrine every ten minutes. Frequent use of phenylephrine should be avoided as it causes corneal oedema.
Post-operative Management [Table - 3]
Follow-up examination is done with binocular indirect opthalmoscope daily while in hospital and weekly thereafter for six weeks. As victrectomy does not eliminate basic pathology, quarterly follow-up is required to know the progress of the disease.
| Surgical technique|| |
This can be divided into two broad groups: 1. Basic surgical techniques common to all procedures
2. Special techniques for specific needs
| Basic surgical techniques|| |
(a) Pre-operative Preparation
Before scrubbing microscope is adjusted and foot pedal controls are checked. After scrubbing, port size of probe is selected and it is connected to main console with twin bore tubing. Cutting rate and suction rate are adjusted and set at desired level. The height of infusion bottle is adjusted for getting desired level. The height of infusion bottle is adjusted for getting desired pressure at infusion site.
In a short procedure lasting less than two hours, e.g., vitrectomy for victreous haemorrhage, lensectomy, local anaesthesia using Bupivacaine 0.5% (Marcaine) is used. Otherwise in all cases and in young children general anaesthesia with muscle relaxants is used.
(c) Operative Procedure
(i) Selection of sclerotomy site
After cleaning and draping, sclerotomy site is selected with the help of corneal transillurninator, avoiding vitreous base and major vessels and nerves, keeping in mind the ease of manipulation. Usually this is 3.5 to 4.0 mm. away from limbus and two in temporal and one in nasal quadrants.
(ii) Making Sclerotomies
Coujunctiva is cut with scissors at the site and bleeders cauterized. A stab incision is made with myringotomy knife (V. Mueller) with a point directed to pupillary area for anterior segment surgery and centre of vitreous cavity for vitrectomy. This is widened with the help of stilleto to 3.0 mm. size so that it is adequate for ocutome needle, making it water tight closure.
Before making sclerotomies make sure that eye is not too soft. Soft eye offers least resistance and makes precise incision difficult and can cause uveal separation. In such cases tension is built up by injecting saline with 30 gauge needle prior to sclerotomy.
For vitrectomy three sclerotomies are performed each for Ocutome, endolluminator and infusion. These are made in different quadrants, two in temporal and one in nasal for ease of manipulation. The infusion cannula is fixed by a 4'0 mattress suture to sclera.
For anterior segment surgery, only two sclerotomies are made for Ocutome and infusion each. When a sclerotomy is not in use it is closed by a plug for keeping the cavity water tight. For anterior segment surgery limbal approach can be used in the same way as paras plana surgery.
(iii). Closure of wound
At the conclusion of surgery sclerotomies are closed with 6'0 nylon suture.
This is a vital step as majority of wound complications occur at this stage. To prevent this, it is necessary to see that instruments are withdrawn from a soft eye only. To achieve this, infusion is stopped and only suction is carried out at the end of surgery till eye becomes soft.
| Special techniques|| |
(a) Lensectomy [Figure - 9]
Myringotomy knife is directed into the lens after it passes into the sclera. Then through the same opening fragmatome is introduced. Once it is in mid pupillary area fragmentation is begun in the central part and then continued in the peripheral part. While doing so care is taken not to injure anterior or posterior capsule or the globe. This can best be done by keeping the tip of the instrument constantly under observation. After fragmentation is over fragmatome is withdrawn and Ocutome is introduced through same opening. Ocutome is usually operated at suction rate of 7 mm. of Hg. and cutting rate of 150/minute. Infusion is through second sclerotomy at paras plana usually at 160° from first for better bimnual manipulation. After removing the lens matter anterior capsule is nibbled and then posterior capsule is removed. Slit examination through microscope is helpful in identifying tags of capsule at this stage.
In cases of soft lenses Ocutome alone is used.
The same procedure can be done with timbal approach (See [Table - 4]).
(b) Membraneciomy [Figure - 10]
Myringtomy knife is passed into the central (pupillary) portion of membrane after making sclerotomy. Ocutome probe is introduced into the opening so created in the membrane. Ocutome is operated with suction at 5 mm. of Hg. and pupillary area is cleared of the membrane.
When membrane was found thick to be cut by Ocutome (a delicate instrument) wide angle cutter vitreophage was used. In two cases where vitreophage failed Vanna's scissors were used. However, proper instrument in such cases is intraocular scissors (20 gauge from Medical Workshop, Holland M.125A).
This can also be done through limbal approach. (See [Table - 4]).
(c) Vilrectomy [Figure - 11]
After making three standard sclerotomies for Ocutome, infusion and illuminator, vitrectomy is begun with Ocutome.
Up to mid cavity vitrectomy intraocular illumination is not required; para-axial and co-axial illumination are sufficient.
For posterior vitrectomies neutralising contact lens (Luma lens or Machmer's lens) is required and intraocular illumination is a must as the light from the microscope cannot reach.
As intensity of illuminator is low it should be kept as near the Ocutome as possible so that better view is obtained without obstructing the Ocutome. The endoiluminator should not be held too near the retina on same spot for longer time as this causes photic damage to retina which is reversible in initial stages only.
For removing hyaloid membrane or any other membranes sea to land or land to sea technique can be employed after piercing it. Sea to land is better as it is under better visual control [Figure - 12].
(i) Neovascular membrane
Management of neovascular membrane during vitrectomy is a problem. It can be managed by diathermizing the base of the membrane with (a) underwater diathermy or (b)bipolar diathermy and then removing them with Ocutome without any problem of bleeding.
Another way of doing it is cutting and removing the whole saffolding of the neovascular membrane from its base at retina to its apex in the vitreous and making it free floating. At the end of the surgery it settles on retina and does not progress. It may regress under such circumstances.
(ii) Removal of a pool of blood
For this Charles fluted needle is used. Its inner end is kept into the pool. After proper positioning, fingertip is removed from external opening which drains the blood out. During this procedure infusion is running providing necessary force for draining the blood out.
(d) Lens extraction and Vitrectomv
If lens is not too hard it is removed through paras plana as in cases of lensectomies. Hard lenses are removed through limbus intracapsularly prior to paras plana surgery. After watertight closure of the wound paras plana surgery is begun.
(e) Paras plana surgery and retinal detachment
Opacities obscuring the view and detailed examination are removed through paras plana. Plugs are used to close sclerotomies and scleral buckling procedure is done.
This is also done for removing the membranes in cases of retinal detachment complicated by massive periretinal proliferation (M.P.P) and in traction retinal detachments to remove traction bands and membranes.
Besides these, paras plana surgery gives following opportunities for sclera-1 buckling procedures
1. Closure of retinal breaks by (a) endodiathermy (bipolar or under water) (b) intraocular cryo coagulation (c) endophotoccagula
2. Internal drainage of subretinal fluid.
3. Fluid gas exchange.
4. Hydraulic dissection.
Last three of these are useful in improving results in complicated cases. Of these, internal drainage of subretinal fluid and fluid gas exchange are done with Charles fluted needle and deserve special mention.
(i) Internal drainage of subretinal fluid
Inner end of Charles fluted needle is kept into the subretinal space through the retinal break and thus subretinal fluid is evacuated. Dependent positioning of the hole is important for complete evacuation.
(ii) Fluid gas exchange
The Charles flute needle is kept in a dependent position of eye and gas is introduced through separate sclerotomy which drains all the intraocular fluid through Charles flute needle and fills the eye ball with gas.
| Complications|| |
Complications of paras plana surgery are divided mainly into two groups. Operative and post-operative.
A. Operative complications [Table - 5]
They are divided into (i) Common to all surgeries (ii) common to anterior segment surgeries (iii) posterior segment surgeries.
1. Common operative complications
1. Wound complications
(a) Prolapse of uveal tissue occurred in two cases of vitrectomy for vitreous haemorrhage at the end of surgery on removing the instruments from the eye. This was on withdrawing the instruments from the eye and managed by reposition and excision remaining tissues.
(b) Vitreous loss [Figure - 13] was seen in 9 cases of which 8 were for lensectomies and one for vitrectomy for vitreous haemorrhage on withdrawing the instruments from the eye. This was managed by removing the vitreous after cutting it with scissors at the wound and then closing the wound.
Both these complications had no effect on outcome of surgery or during post-operative period.
Both these can be avoided by withdrawing the instruments from the soft eye only and plugging one sclerotomy before making the other.
(c) Dialysis noted in two cases caused retinal detachments. They were due to posteriorly placed sclerotomies. Probably transillumination was not performed in these cases.
This was seen in three cases. Two were of vitrectomy for vitreous haemorrhage and managed by injecting 1:10,000 Adrenaline into anterior chamber with 30 gauge needle through limbus. In a case of lensectomy for congenital cataract, sphincteromy was done to overcome miosis.
II. Complications of anterior segment surgery
1. Dropping of lens matter [Figure - 14][Figure - 15]
This occurred in 22 cases of which 19 were of lensectomies and 3 were for after cataracts. Of the 19, one was for lensectomy combined with vitrectomy for vitreous haemorrhage. Soft lens matter was dropped in 20 cases while hard was dropped in 2 cases. Both these had hardness of Grade IV on scale as 4 as evaluated with slit lamp pre- operatively. In 20 soft lens matter dropping, accidental rupture of posterior capsule or pre-existing rupture as in traumatic cataract or after cataract was responsible.
To have an idea on consequences of lens dropping on post-operative complications and visual recovery, causes of poor recovery in these cases are analysed. [Table - 6]
They can be responsible for iridocyclitis and glaucoma (phacolytic). This seems to be quantitative response as in a case of hypopyon iridocyclitis removal of lens matter by second surgery resulted in a control of iridocyclitis. From this it seems, dropping of soft lens matter is of least significance as it causes few complications and even then of least severity and gets absorbed with passage of time.
2. Iris complications.
This was seen in 9 cases as accidental sphincterotomy and accidental iridectomy in cases of lensectomies. These were because of (i) Presence of posterior synechiae in cases of complicated cataract lead to inadvertent sphincterotomy. (ii) Small size of eye ball and inadequate miosis making manoeuvre difficult in congenital cataracts. (iii) Excessive suction and rapid speed of surgery. (iv)Miosis occurring surgery.
3. Bleeding from cut end of iris.
This was seen in a case of complicated cataract and membranectomy probably because of inability of iris tissue to retract.
This stopped by itself and was of no signi ficance.
4. Metallic shavings.
These were seen in 3 cases. 2 were of lensectomies for hard cataracts and one of thick membronectomies. This reflects the strain on instrument because of hardness of lens/membrane.
III. Complications of posterior segment surgery
1. Lens injury.
This occurred in 2 cases. In one it was of vitrectomy for vitreous haemorrhage and with other it was vitrectomy with sclera buckling. In the first, lensectomy was done at the same sitting. In the other, lens became cataractous and mature cataract was removed four months later.
2. Intraocular haemorrhage.
This was seen in 5 cases from different sites and managed differently as shown in [Table
3]. Accidental retinal breaks.
This was noted in only one case and cryo application was done.
It also happened in 5 other cases but were not detected on table.
B. Post operative complications [Table - 7]
1. Corneal complications
They are summarized in the table. They were seen mainly in cases where anterior segment surgery was performed and capsule was absent. Epithelial oedema seen was secondary to increased intraocular tension and disappeared on control of tension. Endothelial decompensation was seen in 5 cases. of these two were transient and disappeared with routine therapy. In two cases of lensectomies and in one case of lcnsectomy it became permanent. All these cases had infusion through limbus and prolonged surgery as a common finding suggestive of damage done by infusion of saline through anterior approach for a prolonged time.
Other corneal complications were self-limiting and insignificant.
This was seen in 7 cases. Of this, one of lens extraction and vitrectomy and 3 of vitreous haemerrhage were associated with development of rubeosis. In all the 7 cases
it disappeared with rest and passage of time.
This developed in 4 cases and all were diabetics.
This was seen in 18 patients in all. Details are given in the table. Neovascular glaucoma was seen with rubeosis iridis. All cases except neovascular and absolute responded well to specific therapy
lridocyclitis was seen mainly in anterior segment surgery and was usually associated with lens dropping. This was less than expected because of a large number of complicated cataracts. Reason might be less trauma, complete removal of lens matter, anterior vitrectomy performed alongwith and surgery done during quiescent stage of disease. No cause could be found for the iridocyclitis in cases of vitrectomy for vitreous haemorrhage.
6. Mature cataract.
This was seen in 4 cases and were removed intracapsularly later on. They are thought to be because of:
(i) Progression of pre-existing disease.
(ii) Accidental touching of lens
(iii) Prolonged surgery with infusion of saline.
7. Recurrence of vitreous haemorrhage.
Minimal haemorrhage causing hazy media in immediate post-operative period is a rule. This clears up gradually. In 10 cases of vitrectomy and 4 cases of lens extraction with vitrectomy it appeared in late postoperative period. In all but 2 cases of vitreou, haemorrhage it cleared with rest and passage of time. Of the two, in one case vitreous lavage was done to clear it while in one case of absolute glaucoma no attempt was made. It was noted that rate of clearance of vitreous haemorrhage with rest is faster in aphakic eyes compared to phakic eyes.
8. Wound complications.
These were not significant and were seen in two cases. In one it was in the form of fibrovascular in growth and in another it was in the form of cyst at wound site with dragged membrane at the site. This happens because of sudden withdrawal of instrument from the eye with normal or high intraocular pressure, which can be avoided by gradual withdrawal from a soft eye.
9. Retinal detachment.
This occurred in 13 eyes. Of these 10 occurred following vitrectomy for vitreous haemorrhage. Of these, 3 were traction retinal detachment because of progress of disease process, Eales' in two and diabetic retinopathy in one. Of the remaining 10, 4 were because of dialysis, 2 in membranectomy and 2 in vitrectomy group. The remaining were rhegmatogenous because of break.
| Observations|| |
1. Visual recovery [Table - 8]
Visual recovery is shown in the table in a typical way so that any improvement or deterioration from a pre-operative level can be judged very easily. In lensectomy group in majority it was light perception and projection ++++ but in young children it was not possible to determine precisely and so only postoperative results as available are given. In all but 4 patients it remained stationary or improved. It was because of:
(i) Corneal decompensation following membranectomy.
(ii) Neovascular glaucoma following lens extraction with vitrectomy for vireous haemorrhage.
(iii) Absolute glaucoma following vitrectomy for vitreous haemorrhage.
(iv) Traction retinal detachment following vitrectomy for vitreous haemorrhage.
To see whether long-standing vitreous haemorrhage has any deleterious effect on function or not, long-standing cases of vitreous haemorrhage are analyzed separately [Table - 9]. It shows that vitreous haemorrhage of long duration has no ill effects no function of retina in praticular and eye ball in general.
II. Causes of poor visual recovery [Table - 10]
Operative complications were responsible only in 7 cases. Of these, 3 had corneal decompensation and one had severe iridocyclitis. In the remaining cases it was not related to surgery.
III. Outcome of surgery in cases associated with scleral buckling [Table - 11]
In remaining cases,visual recovery and causes of poor recovery gives a good idea about the status of surgery qualitatively and quantitatively. But in combined procedure it becomes difficult to evaluate each individually from this only. In all these cases membranectomiesl lensectomies with scleral buckling both techniques were perfect and 100°success rate was obtatined. This has an advantage of performing one stage surgery instead of the conventional two stage surgery. This is not so in cases of vitrectomy and scleral buckling Results with causes of failure are given in [Table - 11].
Follow-up surgical procedures after vitrectomy for vitreous haemorrhage [Table - 12]
These were undertaken to improve visual acuity, to prevent further damage, to relieve symptoms or to find out pathology and its status, as shown in [Table - 12]. Ability to perform fluorescein angiography, cryo prphylaxis, laser photocoagulation and scleral buckling procedure speaks of clarity of media and extent of clear media.
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[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7], [Figure - 8], [Figure - 9], [Figure - 10], [Figure - 11], [Figure - 12], [Figure - 13], [Figure - 14], [Figure - 15]
[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5], [Table - 6], [Table - 7], [Table - 8], [Table - 9], [Table - 10], [Table - 11], [Table - 12]