Postsurgical intraocular pressure elevation

Postsurgical intraocular pressure elevation Audrey Tuberville, M. D. Takako Tomoda, M. D. Ilana N issenkorn, M. D. Thomas O. Wood, M. D. Memphis, Tennessee

ABSTRACT Eighty-six eyes undergoing intraocular surgery were evaluated for the incidence of acute postoperative intraocular pressure (lOP) rise and the relationship between initial and delayed postoperative pressure elevations. Our results show that 22.5% of penetrating keratoplasty (triple procedures and aphakic transplants) and 32% of extracapsular cataract extraction (ECCE) patients developed an initial postoperative pressure greater than 23 mm Hg. Ninety percent of penetrating keratoplasty patients and 46% of ECCE patients who had an initial pressure elevation developed a delayed pressure elevation. Fortythree percent of penetrating keratoplasty and 32% of ECCE patients with a normal initial postoperative lOP developed a delayed pressure increase. Extracapsular cataract surgery patients developed late pressure rise with approximately the same frequency as normal eyes on prolonged topical steroid therapy, regardless of the initial postoperative pressure. Key Words: aphakic penetrating keratoplasty, extracapsular cataract extraction, intraocular lens, postsurgical pressure rise, secondary glaucoma, triple procedure

Investigators have reported that intraocular pressure (lOP) is acutely elevated in 25% of patients undergoing intracapsular cataract surgery when alpha chymotrypsin is not used,1 and in approximately 75% of patients having intracapsular surgery with alpha chymotrypsin. 2 Aphakic keratoplasty patients have acute pressure elevation when similar sized donor button and recipient bed cuts are used. 3,4 The lOP in most of these eyes returns to normal in a few days regardless of therapy. 4

Since these observations were made, there have been major changes in surgical techniques. Extracapsular extraction is favored for patients having cataract surgery or undergoing combined penetrating keratoplasty, cataract extraction, and intraocular lens implantation (triple procedure). Our current techniques for aphakic keratoplasty or triple procedure patients include a donor button larger than the recipient bed, 5 a 360 0 beveled ledge in the posterior recipient corneal bed,6,7 and a shallow (one-third depth)

From the Department of Ophthalmology, University of Tennessee Center for Health Sciences, Memphis, Tennessee. Presented in part at the Association for Research in Vision and Ophthalmology meeting, Sarasota, Florida, May 1982. Reprint requests to Audrey Tuberville, M.D., 956 Court, Room 2D-29, Memphis, Tennessee 38163. AM INTRA-OCULAR IMPLANT SOC J-VOL. 9, SUMMER 1983

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single running 10-0 nylon closure. 6 ,7 The objectives of this study were to determine (1) the incidence of acute postoperative lOP elevation applying the recently developed surgical techniques mentioned in the preceding paragraph for cataract extraction and patients undergoing triple procedures or aphakic transplants; (2) whether an acute pressure rise is useful in predicting delayed lOP elevation. 8

MATERIALS AND METHODS We studied 86 eyes in three operative categories: 41 eyes underwent extracapsular cataract extraction (ECCE) and posterior chamber intraocular lens insertion; 20 eyes had triple procedures; and 25 eyes had aphakic penetrating keratoplasty. Eyes with preoperative glaucoma or lOP greater than 23 mm Hg were excluded from the study. All procedures were performed by one surgeon. A planned extracapsular technique with interrupted 10-0 nylon suture closure at two-thirds depth was used for cataract patients, and a single running 10-0 nylon closure at one-third de~th was used for corneal transplant patients. Healon was not used in any case nor was a primary discission of any posterior capsule made. Keratoplasty patients received disparate-sized grafts using an 8.0-mm donor and 7.5-mm recipient bed. All patients received a subconjunctival injection of 10 mg dexamethasone at the end of the procedure and were subsequently treated with topical steroids. Intraocular lens patients received topical steroids six times a day from the third postoperative day, and were then tapered to one drop per day over the next six weeks. Aphakic transplant eyes without intraocular lenses received steroids three times a day beginning on the third postoperative day. At eight weeks postoperatively, topical steroids were usually discontinued in cataract patients and continued once or twice daily in transplant patients with or without intraocular lens implantation. Intraocular pressures were measured by applanation with a G{)ldmann tonometer prior to surgery and at each postoperative examination for one year. Using topical anesthesia and a sterile fluri-strip, we encountered no difficulties performing postoperative tonometry. It is done routinely on all our postoperative patients at every examination. RESULTS The mean lOP on the first postoperative day in all patients was 20.6 mm Hg. Twenty-seven percent of the 86 eyes had a pressure greater than 23 mm Hg on the first day following surgery. Cataract patients had a mean pressure of23 mm Hg; triple procedure patients, 18.5 mm Hg; and aphakic transplants, 18.2 mm Hg (Table 1). 310

Table 1. Mean lOP one day postoperatively. Number of Patients

lOP

Cataract extraction with IOL implantation

41

23.0

Triple procedure (cataract extraction, IOL implantation, corneal transplantation)

20

18.5

Aphakic keratoplasty

25

18.2

Total

86

20.6

Operative Category

Of the patients demonstrating an acute pressure elevation in the immediate postoperative period, 32% of ECCE patients had a mean lOP of 38.2 mm Hg. Twenty-five percent of triple procedure patients had a mean pressure of 27.2 mm Hg; and 20% of aphakic transplant patients had a mean pressure of 31 mm Hg (Table 2). Table 2. Patients with initial postoperative lOP greater than 23 mm Hg. Percentage

Mean lOP

Cataract extraction with IOL implantation

32%

38.2

Triple procedure (cataract extraction, IOL implantation, corneal transplantation)

25%

27.2

Aphakic keratoplasty

20%

31.0

Mean

27%

34.3

Operative Category

Forty-six percent of the cataract patients demonstrating acute pressure rise developed a delayed mean pressure elevation to 35.2 mm Hg (Table 3). Ninety percent of all transplant patients with an initial pressure elevation developed a delayed elevation, whereas 43% with normal initial pressure developed late lOP rise (Table 3). This difference (90% versus 43%) is statistically significant with P<0.025 with chi square test (Table 3). All triple procedure patients with an initial lOP elevation developed a delayed pressure rise, and 80% of the transplanted aphakic eyes with an initial pressure rise developed a delayed pressure elevation. In triple procedure patients, the mean delayed pressure elevation was 36 mm Hg, and in aphakic transplants, 32.8 mm Hg (data not shown in table). Patients with normal pressure postoperatively developed delayed pressure elevations in the following percentages: cataract 32% (mean 27.5 mm Hg); triple

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Table 3. Delayed lOP elevation in ECCE with IOL insertion patients and triple procedure or aphakic keratoplasty patients. Percentage of Mean lOP Initial lOP Patients with (mm Hg) at Operative Category (mm Hg) Delayed lOP Rise Delayed Rise ECCE with IOL

<23 >23

32% 46% 37%

27.5 35.2 29.8

<23 >23

43%* 90%* 53%

33.4

Total patientst Transplants (triple procedure or aphakic keratoplasty) Total patientst

26.1 27.1

*p<0.025 chi square tWithout regard to initial lOP

procedures 40% (mean 25.7 mm Hg); aphakic transplants 45% (mean 26.1 mm Hg). The mean lOP in patients who developed a delayed lOP elevation was higher if the pressure was elevated immediately following surgery than if the pressure was normal initially. Delayed pressure elevation occurred among the three operative categories at different times. Mter ECCE the delayed pressure elevation developed at a mean of seven weeks whether the lOP was normal or elevated on the first postoperative day. An lOP rise occurred at a mean of two-and-one-half weeks in triple procedure patients if the pressure was elevated initially, and three-and-one-halfweeks ifthe pressure was normal initially. Patients having aphakic corneal transplants had lOP elevation at six weeks if the pressure was elevated immediately following surgery, and at 14 weeks if the lOP was normal in the early postoperative period (Table 4). Table 4. Time (weeks) to delayed lOP elevation. Initial lOP (mm Hg)

Cataract

Triple Procedure

Aphakic Keratoplasty

<23 >23

7.7 7.0

3.3 2.5

14.0 6.5

One aphakic transplant patient developed an iridocorneal adhesion with elevated lOP, requiring cyclocryotherapy. In all other patients the lOP was controlled using topical medications, with timolol used most frequently. Twenty percent of all patients developing a delayed pressure rise required more than one topical glaucoma medication. Carbonic anhydrase inhibitors were not required in any case.

DISCUSSION In the initial postoperative period, only ECCE patients with implantation of an intraocular lens had a mean pressure greater than 20 mm Hg. Position of the incision may play a role in the 'acute pressure rise following cataract surgery. Rothkoff, Biedner and Blumenthal reported that cataract patients with corneal rather than limbal incisions have a significantly lower incidence of acute postoperative pressure elevation, which they attribute to less surgical damage to the trabecular meshwork. 9 In the ECCE group, an initial lOP elevation was not useful in predicting a delayed pressure rise. However, aphakic keratoplasty and triple procedure patients with an early postoperative lOP rise developed a delayed pressure elevation in a statistically significant greater number of cases than did patients with normal lOP just after surgery (90% versus 43%). In the keratoplasty and cataract patients who developed a delayed pressure rise, those with initially elevated pressure tended to have higher pressures than those with initially normal postoperative pressure. Triple procedure patients developed a pressure elevation sooner than aphakic keratoplasty or ECCE patients. These results emphasize the importance of measuring the lOP preoperatively and at frequent postoperative intervals in patients having intraocular surgery. Becker and Mills demonstrated that 44% of normal eyes over the age of 40 develop an elevated lOP after topical steroids for several weeks. lO Cataract patients with intraocular lens insertion are treated with topical steroids longer than patients without intraocular lenses. The delayed pressure rise that developed in 37% of the cataract-intraocular lens group (without regard to the initial lOP) may be a steroid response (Table 3). Aphakic keratoplasty patients are maintained on topical steroid therapy for extended periods. The delayed pressure rise in this group (53%) probably represents a combination of steroid responsiveness and compromised trabecular filtering function secondary to the sequelae of chronic inflammation in these diseased eyes (Table 3). Medical control oflate pressure rise was relatively simple in all but one case; 80% required only timolol or a reduced dosage of the topical steroid. In 1969 the incidence of acute pressure rise following aphakic transplants was reported as approximately 70%.3 In 1978, Zimmerman et al. described a procedure, using a 0.5 mm larger corneal donor button than recipient bed, which reduced their incidence of postoperative pressure rise from 74% to 41%.5 They hypothesized that the corneolimbal angle is increased by this method, which avoids decrease in facility of outflow caused by angle crowding when similar sized button and bed are used.

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In 1978, Wood described a technique in which a posterior 360°-ledge is cut in the recipient bed to support the 0.5 mm larger donor button. 6 This seals the wound posteriorly, allowing a shallow (one-third depth) single running 10-0 nylon closure that avoids mechanical flattening of the graft. 6, 7 These three factors combined-disparate graft size, posterior recipient bevel, and shallow suture closure-allow the graft to expand anteriorly, which effects a more normal corneal curvature. The benefits of using these techniques include early visual rehabilitation, ease of immediate applanation tonometry as a result of normal graft curvature, and a wider corneolimbal angle with consequent reduction in incidence of acute pressure rise from 70% in 1969 to 23% reported in this study. These advances have contributed to improved long-term postoperative results with fewer problems related to secondary glaucoma. REFERENCES 1. Kirsch RE: Glaucoma after cataract extraction associated with use of alpha-chymotrypsin. In: Theodore FH, ed., Complications After Cataract Surgery. Boston, Little, Brown and Co, 1965, pp 233-247

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2. Rich WI. Radtke ND, Cohan BE: Early ocular hypertension after cataract extraction. Br] Ophthalmol 58:725-731, 1974 3. Irvine AR, Kaufman HE: Intraocular pressure following penetrating keratoplasty. Am] Ophthalmol 68:835-844, 1969 4. Wood TO, West C, Kaufman HE: Control of intraocular pressure in penetrating keratoplasty. Am] Ophthalmol74:724-728, 1972 5. Zimmerman T, Olson R, Waltman S, Kaufman H: Transplant size and elevated intraocular pressure; postkeratoplasty. Arch Ophthalmol 96:2231-2233, 1978 6. Wood TO: Early visual rehabilitation in aphakic transplants. In Emery JM, ed., Current Concepts in Cataract Surgery; Selected Proceedings of the Fifth Biennial Cataract Surgical Congress. St. Louis, The CV Mosby Co, 1978, pp 292-296 7. Wood TO: Corneal transplants and intraocular lenses. In: Emery I. Jacobson AC, eds., Current Concepts in Cataract Surgery; Selected Proceedings of the Seventh Biennial Cataract Surgical Congress. New York, Appleton-Century-Crofts, 1982, pp 169-173 8. Olson RJ, Kaufman HE: Prognostic factors of intraocular pressure after aphakic keratoplasty. Am] Ophthalmol86:510-515, 1978 9. Rothkoff L, Biedner B, Blumenthal M: The effect of corneal section on early increased intraocular pressure after cataract extraction. Am] Ophthalmol 85:337-338, 1978 10. Becker B, Mills DW: Corticosteroids and intraocular pressure. Arch Ophthalmol 70:500-507, 1963

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