Axial length decrease accompanying successful glaucoma filtration surgery

doi:10.1016/S0161-6420(99)90531-6

Ophthalmology

Volume 106, Issue 12, 1 December 1999, Pages 2307-2311

Presented in part at the American Academy of Ophthalmology annual meeting, New Orleans, Louisiana, November 1998.

https://doi.org/10.1016/S0161-6420(99)90531-6 Get rights and content

Abstract

Objective

To evaluate change in axial length measurement after successful glaucoma filtering surgery.

Design

Retrospective consecutive case series.

Participants

Sixty-two patients with phakia who underwent primary trabeculectomy.

Intervention

The A-scan biometry of ocular axial length before and after trabeculectomy.

Main outcome measures

Changes in ocular axial length measurement after successful trabeculectomy were analyzed.

Results

The mean decrease in axial length measurement was 0.423 mm (range, −2.8 to +0.5 mm). Regression analysis yielded a statistically significant association between decrease in axial length measurement and age (P = 0.0001) and post-trabeculectomy intraocular pressure decrease greater than 30 mmHg (P = 0.01). Analysis of variance revealed a significant association between decrease in axial length measurement and use of antimetabolite (P = 0.005). Pseudophakic axial length measurements increased an average of 0.275 mm compared to the axial length after trabeculectomy and before cataract surgery.

Conclusions

Axial length measurement decreased in 32 of 62 eyes after successful initial trabeculectomy. A decrease in axial length measurement may have an influence on intraocular lens calculations. Therefore, the authors recommend that an axial length measurement be obtained on phakic eyes before an initial trabeculectomy to reduce the risk of an inaccurate intraocular lens power calculation based on post-trabeculectomy axial length measurements.

Section snippets

Patients and methods

Patients who were scheduled for an initial surgical trabeculectomy underwent preoperative evaluation consisting of refraction, tonometry, slit-lamp biomicroscopy, and ophthalmoscopy. Patients underwent a general physical examination and laboratory evaluation, including complete blood count, fluid balance, and electrolytes, and, when indicated by medical history, chest x-ray, and electrocardiogram. All patients underwent an A-scan biometry by one of us (CAM) to determine axial length using the

Results

Sixty-two phakic patients underwent 67 initial trabeculectomies (5 fellow eyes underwent surgery, but the second operated eyes were not included in the analysis). There were 30 men (average age, 61.5 years of age; range, 33–81 years) and 32 women (average age, 64.2 years of age; range, 27–78 years). Thirty eyes were right eyes. Visual acuity before trabeculectomy ranged between 20/15 and counting fingers. Preoperative refractive error (in spherical equivalent) ranged between −24.87 and +7.12

Discussion

Cataract progression is accelerated by glaucoma surgery, and therefore patients with successful glaucoma surgery may face cataract surgery earlier than would their peers.6 The advent of IOL implantation in conjunction with cataract extraction has enhanced the postoperative vision of almost all patients. Pseudophakia is especially useful in patients with a successful glaucoma filtering bleb because it eliminates the need for and the risk of patients wearing a contact lens to correct aphakia.

References (10)

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Author’s reply
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There are more references available in the full text version of this article.

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Citation Excerpt :
Law et al. found that axial length reduction correlated significantly with lower postoperative IOP but did not correlate with reduction in IOP in combined phacotrabeculectomy.2 Cashwell et al. reported that axial length measurement increased by an average of 0.275 mm after cataract surgery in a successfully trabeculectomized eye.11 Muallem et al. speculated that a possible increase in IOP in post-trabeculectomy eyes after cataract extraction could lead to axial length elongation and a resultant myopic shift in final refraction.8
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Axial length decrease accompanying successful glaucoma filtration surgery

Abstract

Objective

Design

Participants

Intervention

Main outcome measures

Results

Conclusions

Section snippets

Patients and methods

Results

Discussion

Ophthalmology

Am J Ophthalmol

Am J Ophthalmol

Am J Ophthalmol

Ophthalmology