Transactions 29th European Strabismological Association Meeting – de Faber (ed) © 2005 European Strabismological Association, ISBN 04 1537 211 9

Refractive surgery: strabologic patients management

L. Sabetti, L.D’Alessandri, A. Fiasca & K. Salvatori

L’Aquila University, City of L’Aquila, Italy

ABSTRACT: 84 patients (35 M and 49 F; mean age 35,19 / 8,03) with refractive errors and ocular motility disorders (ET, XT, convergence defects) underwent refractive surgery. Only patients with a valid binocular function were selected for this study. 65 patients underwent PRK and 19 underwent LASIK. At two years follow up have been evaluated. Results: only 1 patient (0.01%) manifested diplopia postsurgery.

Conclusions: ocular motility disorders are not absolute contra-indication to refractive surgery.

1INTRODUCTION

In last years many patients having refractive surgery reported a decompensated strabismus and binocular diplopia (Kim 2000; Holland 2000). It should be caused by the monovision during the period between the treatment of the first and the second eye (Schuler 1999).

The preoperative evaluation for refractive surgery with excimer laser has always been based on a complete ophthalmologic examination that included: careful refraction with and without cycloplegia, contact lens use, presence of corneal disease and dry eye syndrome, pupil size, corneal topography and corneal thickness. It is still not clear the importance of preoperative orthoptic evaluation (Godts 2004). The aim of this study is to evaluate the binocular function in patients with ocular motility defects before and after refractive surgery in order to identify risk groups for post treatment diplopia.

2MATERIALS AND METHODS

Eighty four patients (35 M and 49 F, mean age 35,19 / 8,03) that presented refractive errors (32 hyperopic, 52 myopic) with ocular motility disorders (18 accommodative strabismus: 6 myopic XT and 12 hyperopic ET; 52 no accommodative: 20 myopic XT, 12 myopic ET, 10 hyperopic ET and 10 hyperopic XT; 14 convergence defects) underwent a complete ophthalmologic visit and orthoptic evaluation. Ophthalmologic examination included refraction with and without cycloplegia, Goldman tonometry, biomicroscopy of the anterior segment, funduscopic examination, pupil size, corneal thickness, corneal topography and endothelial microscopy. Orthoptic examination evaluated the ocular motility in the nine gaze positions, the presence of anomalous head positions, objective and fusional convergence, Bagolini’s red filter, Worth and Micro-Worth, 4-dot test, Lang test (I,II), Titmus, red filter test. Before refractive surgery the angle of deviation was evaluated with prism cover test at near and at distance after a continuous use of a corneal lens for thirty days. After surgery it was measured without correction.

Only patients with a valid binocular function were selected for this study. 4 patients with profound suppression have been included. Exclusion criterion was diplopia in primary position.

Six myopic patients with accommodative exotropia underwent PRK. Preoperative mean angle deviation was 4 at near and 4.3 at distance; the mean spherical equivalent was 2.38 / 2.9D; the mean UCVA was 20/200; the mean BCVA was 20/22; Lang test mean value was 240 / 79; the Wirt test mean value was 51.20 / 21; the red filter test was negative in all cases.

331

5 hyperopic patients with accommodative esotropia underwent PRK. Preoperative mean angle deviation was 5 at near and 2.4 at distance; the mean spherical equivalent was 4.6 / 0.8D; the mean UCVA was 20/30; the BCVA was 20/20; Lang test mean value was 280 / 156; the Wirt test mean value was 43 / 67.6; the red filter test was negative in all cases.

7 hyperopic patients with accommodative esotropia underwent LASIK. Preoperative mean angle deviation was 5.4 at near and 2.8 at distance; the mean spherical equivalent was 6.46 / 1.1D; the mean UCVA was 20/30; the mean BCVA was 20/20; the Lang test mean value was 520 / 109.5; the Wirt test mean value was 600 / 299.8; the red filter test was negative in all cases.

20 myopic patients with no accommodative exotropia underwent refractive surgery (16 PRK and 4 LASIK). Preoperative mean angle deviation was 6.13 / 3.66 at near and 1.5 / 3.2 at distance; the mean spherical equivalent was 4.86 / 2.24D; the mean UCVA was 20/400; the mean BCVA was 20/20; the Lang test mean value was 250 / 89.44; the Wirt test mean value was 53.79 / 23.09; the red filter test was negative in all cases.

12 myopic patients with no accommodative esotropia underwent PRK. Preoperative mean angle deviation was 4.6 / 3.05 at near and 2 / 2.8 at distance; the mean spherical equivalent was 3.33 / 1.32D; the mean UCVA was 20/160; the mean BCVA was 20/20; the Lang test mean value was 300 / 167; the Wirt test mean value was 45 / 70.7; the red filter test was negative in all cases.

10 hyperopic patients with no accommodative esotropia underwent refractive surgery (6 PRK and 4 LASIK). Preoperative mean angle deviation was 9 / 6.83 at near and 7 / 7.39 at distance; the mean spherical equivalent was 4.42 / 2.80D; the mean UCVA was 20/200; the mean BCVA was 20/20; the Lang test mean value was 520 / 109.5; the Wirt test mean value was 652 / 330.9; the red filter test was negative in 6 cases.4 patients presented profound suppression.

10 hyperopic patients with no accommodative exotropia underwent refractive surgery (8 PRK and 2 LASIK). Preoperative mean angle deviation was 9.5 / 6.40 at near and 3.5 / 4.72 at distance; the mean spherical equivalent was 4.25 / 3.02D; the mean UCVA was 20/60; the mean BCVA was 20/22; the Lang test mean value was 280 / 109.5; the Wirt test mean value was 204 / 333.5; the red filter test was negative in all cases.

14 myopic patients with convergence defects undervent refractive surgery (12 PRK and 2 LASIK). Preoperative mean angle deviation was 8.8fr / 6.6 at near and 4.66fr / 3.2 at distance; the spherical equivalent mean was 4.41 / 2.69D; the mean UCVA was 20/360; the mean BCVA was 20/20; the Lang test mean value was 200; the Wirt test mean value was 64 / 32.86; the red filter test was negative in all cases.

3RESULTS

6 myopic patients with accommodative exotropia that underwent PRK presented postoperative mean angle deviation 0 at near and 0.6 at distance; the mean spherical equivalent was plano; the mean UCVA was 20/20; the mean BCVA was 20/20; Lang test mean value was 236 / 96; the Wirt test mean value was 50.3 / 26.5; the red filter test was negative in all cases.

5 hyperopic patients with accommodative esotropia that underwent PRK presented postoperative mean angle deviation 2 at near and 0.4 at distance; the mean spherical equivalent was 0.17D; the mean UCVA was 20/25; the mean BCVA was 20/20; the Lang test mean value was 278 / 150; the Wirt test mean value was 43 / 67.6; the red filter test was negative in all cases.

7 hyperopic patients with accommodative esotropia that underwent LASIK showed postoperative mean angle deviation 1.7fr at near and 0.2fr at distance; the mean spherical equivalent was plano; the mean UCVA was 20/25; the mean BCVA was 20/20; the Lang test mean value was 520 / 109.5; the Wirt test mean value was 572 / 300; the red filter test was negative in all cases.

20 myopic patients with no accommodative exotropia that underwent refractive surgery (16 PRK and 4 LASIK).showed postoperative mean angle deviation 4 / 2.8 at near and 0.5 / 1.2

332

at distance; the mean spherical equivalent was plano; the mean UCVA was 20/25; the mean BCVA was 20/20; the Lang test mean value was 257 / 94.24; the Wirt test mean value was 54.3 / 26.5; the red filter test was negative in all cases.

12 myopic patients with no accommodative esotropia that underwent PRK presented postoperative mean angle deviation 4 / 2.8 at near and 0.5 at distance; the mean spherical equivalent was plano; the mean UCVA was 20/25; the mean BCVA was 20/20; the Lang test mean value was 300 / 167; the Wirt test mean value was 48 / 70.5; the red filter test was negative in all cases.

10 hyperopic patients with no accommodative esotropia that underwent refractive surgery (6 PRK and 4 LASIK) presented postoperative mean angle deviation 7 / 4.2 at near and 4 / 4.24 at distance; the mean spherical equivalent was plano; the mean UCVA was 20/25; the mean BCVA was 20/20; the Lang test mean value was 550 / 100; the Wirt test mean value was 572 / 334.54; the red filter test was negative in 6 cases.4 patients presented profound suppression.

10 hyperopic patients with no accommodative exotropia that underwent refractive surgery (8 PRK and 2 LASIK)showed postoperative mean angle deviation 6.4 / 5.17 at near and 3.5 / 4.24 at distance; the mean spherical equivalent was plano; the mean UCVA was 20/20; the mean BCVA was 20/20; the Lang test mean value was 240 / 89.4; the Wirt test mean value was 204 / 333.5; the red filter test was negative in all cases.

14 myopic patients with convergence defects that underwent refractive surgery (12 PRK and 2 LASIK) presented postoperative mean angle deviation 10.6fr / 4.24 at near and5.5fr / 3.41 at distance; the mean spherical equivalent was plano; the mean UCVA was 20/20; the mean BCVA was 20/20; the Lang test mean value was 200 / 0.0; the Wirt test mean value was 64 / 32.86; the red filter test was positive for diplopia in one case.

4DISCUSSION

Laser in situ keratomileusis (LASIK) and Photorefractive keratectomy (PRK) are widely used for the correction or myopia hyperopia and astigmatism (Hersh 1998). Few reports of binocular vision impairment and diplopia after refractive surgery have been published (Mandava 1996; Marmer 1987; Schuler 1999; Holland 2000), and there are few reports of the importance of a preoperative orthoptic evaluation (Godts 2004). In this study we emphasize the importance of a detailed orthoptic examination before refractive surgery to exclude risk groups for binocular vision impairment. Pre-existent strabismus and convergence defect should alert the surgeon to possible postoperative binocular problems. So, in our study, an orthopitic evaluation after a continuous use of a corneal lens for thirty days was an invaluable tool to identify risk groups for post treatment diplopia. The only one case of postoperative binocular vision impairment belonged to convergence defects group. This result can be by mere chance, but we suggest that further studies should be done to confirm it.

5CONCLUSIONS

The presence of ocular motility disorders is not an absolute contra-indication to refractive surgery but it must be carefully evaluated every time. In our study only one patient (0.01%) showed worsening of deviation angle and of binocular fusion manifesting diplopia post surgery.

REFERENCES

Gods D, Tassignon MJ, Gobin L. 2004. Binocular visual impairment after refractive surgery. J Cataract Refract Surg. 30:101–109.

Hersh PS, Brint SF, Maloney RK. 1998. Photorefractive keratectomy versus laser in situ keratomileusis for moderate to high myopia; a randomized prospective study. Ophthalmology 105:1522–1523.

333

Holland D, Amm M, De Decker W. 2000. Persisting diplopia after bilateral laser in situ keratomileusis. J Cataract Refract Surg. 26:1555–1557.

Kim SK, Lee JB, Han SH, Kim EK. 2000. Ocular deviation after unilateral laser in situ keratomileusis. Yonsei Med J 41:404–406.

Mandava N, Donnenfeld ED, Owens PL. 1996. Ocular deviation following excimer laser photorefractive keratectomy. J Cataract Refract Surg. 22:504–505.

Marmer RH. 1987. Ocular deviation induced by radial keratotomy. Ann Ophthalmol 19:451–452.

Schuler E, Silverberg M, Beade P, Moadel K. 1999. Decompensate strabismus after laser in situ keratomileusis. J Cataract Refract Surg. 25:1552–1553.

334