Indian Journal of Ophthalmology

ARTICLES
Year
: 1983  |  Volume : 31  |  Issue : 7  |  Page : 830--832

Pressure dynamics following cyclocryotherapy


B Ghosh, HC Agarwal, NN Sood 
 Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India

Correspondence Address:
B Ghosh
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, A.I.I.M.S., New Delhi 110029
India




How to cite this article:
Ghosh B, Agarwal H C, Sood N N. Pressure dynamics following cyclocryotherapy.Indian J Ophthalmol 1983;31:830-832


How to cite this URL:
Ghosh B, Agarwal H C, Sood N N. Pressure dynamics following cyclocryotherapy. Indian J Ophthalmol [serial online] 1983 [cited 2021 Sep 17 ];31:830-832
Available from: https://www.ijo.in/text.asp?1983/31/7/830/29678


Full Text

The pressure lowering effects of cyclocryo theraphy in various types of glaucoma are being gradually understood better with pas­sage of time. The better behaviour of primary glaucomas as compared to secondary glaucomas following cyclocrytherapy is well documented (1). All previous studies however elaborate upon its long term effect on the in­traocular pressure. At present no study is av­ailable which gives us the acute pressure changes following cyclocryotherapy in various types of glaucoma. The present study was therefore undertaken to report on the im­mediate as well as the subsequent effects of cyclocryotherapy on the intracular pressure, in various types of glaucomas. An attempt has also been made to find a correlation if any of the acute initial pressure changes with the sub­sequent fall in intraocular pressure.

 MATERIAL AND METHODS



40 eyes were included in this study. There were 7 cases of primary open angle glaucoma, 6 cases of primary angle closure glaucoma, 2 cases of congenital glaucoma, 6 cases of sphakic glaucoma, 5 cases of neovascular glaucoma and 14 cases of other types of secon­dary glaucoma. All cases were in the advanced stage of disease where maximal medical and or surgical therapy had failed. In all cases 360° cyclocryotherapy with a probe size of 2.5 mm. was due in a single freeze thaw cycle of 60 sec­onds and 15 seconds respectively. 14 spots were applied 3 mm. from the limbus at a temp­erature of -60° . The intraocular pressure was reded preoperatively, immediate post opoera­tively on the table, every hour for next four hours, at 24 hours, 48 hours, I week and then periodically. The minimum follow up period was six weeks.

 OBSERVATIONS



The immediate pressure dynamics following cyclocryotherapy fell into two broad groups. In 87.5% of cases there was a fall in the in­traocular pressure varying from 8.4% to 70% with a mean fall of about 50%. This fall was found to be statistically significant (P<). In the rest 12.5% of cases there was either no fall or a rise in the intraocular pressure.

The pressure in those cases which had an in­itial fall subsequently fluctuated through three different modalities.

a) In 68.5% of cases following the acute fall there was a rise followed by a phase of sustained fall.

b) In 25.7% of cases the acute fall per­sisted.

c) In 5.7% cases after the initial fall there was a rise which continued and then a fall [Figure 1][Figure 2][Figure 3].

At the end of follow up it was observed that nearly 77% of the cases which had an initial fall of intraocular pressure, had an intraoculai pressure of less than or equal to 22 mm. of Hg. [Figure 4]. In contrast only 40% of the cases which did not show an initial fall of intraocular pressure maintained less than 22 mm Hg of IOP at the termination of follow up period [Figure 5].

 DISCUSSIONS



The variation of intraocular pressure sub­sequent of cyclocryo is likely to be dependent upon a multitude of factors e.g. age of the pa­tient, type of glaucoma, duration of glaucoma, the mode and the extrent of cyclocryotherapy done. [1],[2],[3] Older patients with longstanding primary glaucoma tend to show much better control of IOP as compared to younger pa­tients with primary flaucoma or cases with sec­ondary glaucoma.[2]

The initial drop in intraocular pressure in most of our cases could ascribable to the stage of ciliary shock,.induced by sudden freezing. The subsequent phase of rebound activity of the secretary ciliary epithlium, despending upon its vitality,. will lead to the phase of rise of intraocular poressure, till it finally degener­ates. On the other hand the ciliary epoithe­lium might no be able to recover from the ini­tial shock so that the IOP weeks steadily falling leading to the phasic variation.

Few efforts have been made to correlate the initial IOP changes with the final IOP, follow­ing cyclocryotherapy.[1] An attempt was hence made in this study to correlate these factors and to find any correlation factor which would give us a rough prediction of IOP at follow up. It was found that if immediately following the application of cyclocryo, there is an acute fall of I.O.P. then the long term success rate is 77% compared to only 40% control in cases with initial rise or new change. However, no direct correlation between the initial I.O.P. changes with the subsequent I.O.P. level could be attained in any given case of any type of glaucoma.

 SUMMARY



The immediate and subsequent alterations in the intraocular pressure dynamics following cyclocryotherapy in 40 eyes of different type of glaucoma is evaluated. In 87.5% there was an immediate fall in I.O.P. varying from 8.4% to 70% with a mean fall of about 50%. These eyes with initial fall of I.O.P. subsequently went through either of three distinct mod­alities of variations in I.O.P. 77% of the cases which had an initial I.O.P. fall, remained con­trolled as compared to only 40% in cases with initial rise or no change.

References

1Burton, T.C., 1974. Cyclocryotheraphy Current con­cepts in ophthalmology Vol. I V Chapter 9, 103.
2de Roetth, A Jr., 1968. Amer J. Ophthalmol, 66: 1034.
3de Roetth, A Jr., 1966, Amer J. Ophthalmol, 61:443.