Journal of Refractive Surgery

Effect of Punctal Plugs in Patients With Low Refractive Errors Considering Refractive Surgery

Monica B Khalil, MD; Robert A Latkany, MD; Mark G Speaker, MD, PhD; Guopei Yu, MD, MPH

Abstract

ABSTRACT

PURPOSE: To study the effect of punctal plug placement in patients undergoing refractive surgery for correction of poor vision.

METHODS: A retrospective study was performed of 12 patients (21 eyes) who presented for initial refractive surgery or retreatment after LASIK or photorefractive keratectomy to improve visual acuity. Uncorrected visual acuity (UCVA) was documented in each eye. If tear normalization test was positive (indicating dry eye), silicone punctal plugs were placed in the lower lids of both eyes. Subjective patient UCVA and Snellen UCVA were assessed at 1 month.

RESULTS: At 1 month, two eyes improved by three Snellen lines, nine eyes improved by two lines, seven eyes improved by one line, and three eyes remained unchanged. Uncorrected visual acuity was considered statistically significant (P<.0001) using the paired t test. No eye demonstrated decrease in visual acuity. One patient experienced punctal plug extrusion in both eyes. No other adverse outcomes were reported. One patient pursued additional refractive surgery after plug placement. No patient requested plug removal.

CONCLUSIONS: Patients with low refractive errors note improvement in visual acuity after punctal plug placement. [J Refract Surg. 2007;23:467-471.]

Abstract

ABSTRACT

PURPOSE: To study the effect of punctal plug placement in patients undergoing refractive surgery for correction of poor vision.

METHODS: A retrospective study was performed of 12 patients (21 eyes) who presented for initial refractive surgery or retreatment after LASIK or photorefractive keratectomy to improve visual acuity. Uncorrected visual acuity (UCVA) was documented in each eye. If tear normalization test was positive (indicating dry eye), silicone punctal plugs were placed in the lower lids of both eyes. Subjective patient UCVA and Snellen UCVA were assessed at 1 month.

RESULTS: At 1 month, two eyes improved by three Snellen lines, nine eyes improved by two lines, seven eyes improved by one line, and three eyes remained unchanged. Uncorrected visual acuity was considered statistically significant (P<.0001) using the paired t test. No eye demonstrated decrease in visual acuity. One patient experienced punctal plug extrusion in both eyes. No other adverse outcomes were reported. One patient pursued additional refractive surgery after plug placement. No patient requested plug removal.

CONCLUSIONS: Patients with low refractive errors note improvement in visual acuity after punctal plug placement. [J Refract Surg. 2007;23:467-471.]

Dry eye syndrome is documented as one of the most common complications after LASIK surgery, with I incidence reported as high as 59% at 1 month postoperatively.1 Patient dissatisfaction after LASIK due to dry eye has been reported in 30% of cases.2 It is generally thought that all patients experience temporary mild dry eye after refractive surgery.3 Fifteen percent of patients experience moderate dry eye lasting approximately 3 months postoperatively, whereas 5% have chronic severe dry eye that endures for ^6 months.4 This maybe secondary to multiple factors, including decreased corneal sensation due to severing of corneal nerves, which leads to decreased tear production.5 Patient symptoms associated with this condition include irritation, photophobia, foreign body sensation, and decreased visual acuity.

Suboptimal visual acuity after refractive surgery is generally managed by surgical retreatment, especially in patients whose only symptom is blurred vision. Retreatment rates up to 15% have been reported with conventional LASIK.6 However, retreatment increases risk of complications, such as diffuse lamellar keratitis, epithelial ingrowth, striae, infection, prolongation of dry eye, and flap dislocation. These complications are potential causes of decreased best spectacle-corrected visual acuity (BSCVA). Therefore, a non-surgical approach would be ideal to improve visual outcome, patient satisfaction, clinical safety, and efficiency.

A temporary but statistically significant improvement in Snellen visual acuity with instillation of an artificial tear drop in dry eye patients identified with the tear normalization test has been reported.7 The tear normalization test was performed by first evaluating the patient's uncorrected distance Snellen visual acuity. A drop of non- viscous artificial tears, such as carboxyl methylcellulose 0.5% (Refresh Plus; Allergan Ine, Irvine, Calif), was subsequently administered. Visual acuity was checked within 10 to 20 seconds of instillation, beginning at the highest line previously read. Improvement of 5s 1 Snellen line was considered to be a positive test, whereas no improvement was considered to be negative.

Table

TABLE 1Characteristics of Patients Who Underwent Punctal Plug Placement Before Initial or Retreatment Surgery

TABLE 1

Characteristics of Patients Who Underwent Punctal Plug Placement Before Initial or Retreatment Surgery

Decreased visual quality and higher order aberrations are often a source of patient complaints following refractive surgery,8 even in those who do not report dry eye symptoms. Punctal plug placement has been reported to decrease higher order aberrations in patients with dry eye after LASIK.9 This study evaluated the effect of punctal occlusion on overall subjective visual quality in dry eye patients with low refractive errors who were considering refractive surgery.

PATIENTS AND METHODS

Charts were retrospectively reviewed for 152 patients who presented for initial LASIK or retreatment over a 90day period. Thirty-three eyes (18 patients) had spherical equivalent refraction <1.50 diopters (D); however, only 23 eyes of 13 patients had a positive tear normalization test. Fourteen eyes were evaluated for retreatment after initial LASIK surgery, and 3 eyes that had undergone photorefractive keratectomy (PRK) were considering retreatment. Six eyes presented for initial LASIK.

Study criteria included patients interested in laser refractive surgery (retreatment procedure or initial laser consultation) to improve visual acuity without using spectacles or contact lenses. Study design required all patients to have a positive tear normalization test with S2I line of improvement in Snellen uncorrected distance visual acuity. Also included were patients with spherical equivalent refraction of ≤1.50 D.

Patients were excluded if the tear normalization test was negative or if they did not show improvement of at least one line of Snellen uncorrected distance visual acuity after artificial tear instillation. One patient who refused punctal plug placement was excluded. Patients with spherical equivalent refraction >1.50 D were also excluded.

Patient medication use was not a qualifying measure for categorization in this study.

Therefore, 21 eyes of 12 patients (4 men, 8 women) were included in this study. Patient evaluation included UCVA and measured refractive error. Tear normalization test was performed by placing a drop of 0.5% carboxyl methylcellulose (Refresh Plus; Allergan) followed by immediate retesting of uncorrected distance visual acuity. Every patient who demonstrated improvement in visual acuity of at least one Snellen line was offered detailed punctal plug placement discussion and informed consent. All patients had silicone plugs placed in the puncta of the lower lids in both eyes. Patients were permitted to continue use of any drops that were being used prior to plug insertion.

Snellen uncorrected distance visual acuity was evaluated 1 month after plug placement. A line of visual acuity was measured as complete if one or no letters were missed. If more than one letter was missed on a Snellen line, visual acuity was documented as the next higher line. Any adverse reactions, complications, or complaints were noted at this time. The level of subjective change in visual acuity was also recorded.

RESULTS

Mean patient age was 41. 8? 14.3 years (range: 28 to 72 years). Of the 21 eyes included in this study, 14 eyes presented after LASIK, whereas 3 eyes of 2 patients presented after PRK. The date of initial refractive surgery was unavailable for 1 LASIK patient and 1 eye of 1 PRK patient. Mean time between LASIK and punctal plug placement was 46.9 ?33.6 months (range: 4 to 93 months). The PRK patient with available data underwent punctal plug insertion 3 months after surgery. Two patients (4 eyes) were evaluated at the initial consultation for laser vision correction. Spherical equivalent refraction ranged between piano and -1.50 D with mean spherical equivalent of -0.87±0.44 D (median: -0.88 D). Demographics of patients participating in this retrospective chart study are summarized in Table 1.

Table

TABLE 2Uncorrected Visual Acuity (UCVA) Before and 1 Month After Punctal Plug Placement

TABLE 2

Uncorrected Visual Acuity (UCVA) Before and 1 Month After Punctal Plug Placement

Snellen UCVA before and after plug placement is shown in Table 2. Mean UCVA (logMAR) before punctal plug placement was 0.28?0.15 (95% confidence interval [CI]: 0.21%-0.35%). One month postoperatively, two eyes improved by three Snellen lines, nine improved by two lines, and seven improved by one line. Visual acuity in three eyes remained unchanged. No eye demonstrated decrease in visual acuity. Mean UCVA (logMAR) after punctal plug placement was 0.13?0.11 (95% CI: 0.09%-0.19%). Mean difference (logMAR) before and after punctal plug placement was 0.14±0.08. These deviations were considered statistically significant (P<.0001) by paired t test. The Figure summarizes results obtained in this study.

DISCUSSION

Decreased visual acuity after refractive surgery is a common cause of patient dissatisfaction that is often attributed to dry eye. Dry eye patients may present with a wide variety of symptoms, which include foreign body sensation, irritation, photophobia, redness, and blurred vision. However, patients with dry eye often present with blurred vision only. In this study, we included patients whose primary complaint was diminished visual acuity.

Figure. Number of eyes that demonstrated visual improvement measured by lines of Snellen visual acuity (SVA).

Figure. Number of eyes that demonstrated visual improvement measured by lines of Snellen visual acuity (SVA).

Visual function in dry eye patients is impaired when the eye is kept open for 10 to 20 seconds, precipitated by a decrease in blink rate that causes irregularity of the ocular surface. Corneal topography shows associated changes with sustained eye opening in dry eye patients compared to those of normal eyes.10 Surface irregularity and tear film changes have been associated with decreased visual quality and increased higher order aberrations. Improvement in visual acuity and a two- to three-fold reduction of ocular aberrations, shown by wavefront analysis, has been demonstrated with the instillation of artificial tears.11

We previously reported statistically significant improvement in visual acuity, although temporary, with the instillation of artificial tears in dry eye patients.12 High sensitivity and specificity rates were subsequently found when using artificial tears to evaluate the level of improved visual acuity in dry eye patients (ie, tear normalization test).7 This concept is further evidenced by decrease in total, lower, and higher order aberrations with punctal occlusion in the dry eye after LASIK. Visual acuity was also noted to improve significantly based on quantitative and qualitative measures in these patients.9 A clear benefit of punctal occlusion for dry eye patients with impaired functional visual acuity was demonstrated by improving visual acuity and tear film regularity quantified by higher tear break-up time values and higher Schirmer test values.13

Freeman14 first proposed punctal plug use in 1975 for patients with dry eye and subsequently reported 77% improvement in patient symptoms or clinical signs.15 Canalicular occlusion leads to increased goblet cell density and overall tear film stability and function in keratoconjunctivitis sicca.16 Punctal plug placement is associated with high success rates, easy reversibility, low percentage of complications, and creates a relatively simple mechanism for controlling the damage of dry eye in patients who fail topical therapy or require additional relief. Complications are rare, but include plug extrusion, infection, foreign body sensation, epiphora, conjunctival erosion, and formation of pyogenic granuloma.1517 The most commonly reported complication is punctal plug extrusion, which has been documented in approximately 51% of cases.15

A significant risk for refractive regression in chronic dry eye patients was also found. The underlying etiology is thought to be due to epithelial hyperplasia secondary to increased epithelial growth after LASIK, as well as keratocyte apoptosis caused by inflammatory cytokines with ocular surface disease. Furthermore, improvement in visual acuity demonstrated reduction in refractive error and symptoms of dry eye with topical therapy and temporary use of punctal plugs.18

Decreased tear production and ocular surface sensation have been documented with punctal plug placement, which is suggestive of an autoregulatory system involved in tear creation and clearance.19 Future studies with longer follow-up maybe necessary to evaluate sustained improvement in visual acuity.

Our study demonstrates that 86% of patients (7 eyes) gained at least 1 line of Snellen UCVA, whereas 52% (9 eyes) achieved >2 additional lines. Uncorrected visual acuity was statistically significant (P<.0001) in patients considering refractive surgical procedures. One patient pursued additional refractive surgery after plug placement. No patient requested removal of plugs. One patient (2 eyes) experienced punctual plug extrusion and subsequently requested replacement.

This study is limited due to the small population sample. Furthermore, objective measures, including tear break-up time, Schirmer test results, and quantification of superficial punctuate erosions were not assessed by masked examiners due to the retrospective nature. The goal of this study was not to evaluate the ocular surface, but to quantify the number of patients seeking refractive surgery after punctal plug insertion and to highlight the value of punctal plug placement in visually dissatisfied patients by demonstrating subjective improvement in vision, thus decreasing the desire to pursue further refractive surgery (92% of our patients).

These results are consistent with the literature and emphasize improvement in visual acuity in dry eye patients with punctal occlusion, even if the only symptom is decreased visual acuity in the presence of a positive tear normalization test. All patients, except three, acknowledged subjective improvement in vision, and only one patient pursued further refractive surgery evaluation. The level of refractive error necessary to avoid additional refractive surgery was not evaluated. With risks of LASIK retreatments similar to those of primary procedures, avoiding additional surgery by improving vision with the use of punctal plugs is a viable alternative in unsatisfied, low refractive error patients. In light of efficiency, safety, and reversibility of this procedure, we suggest it be considered as the first option for patients with low refractive errors seeking refractive surgery, regardless of the presence or absence of non- visual dry eye symptoms with a positive tear normalization test.

REFERENCES

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3. Toda I, Asano-Kato N, Komai-Hori Y, Tsubota K. Dry eye after laser in situ keratomileusis. Am J Ophthalmol. 2001;132:1-7.

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13. Goto E, Yagi Y, Kaido M, Matsumoto Y, Konomi K, Tsubota K. Improved functional visual acuity after punctal occlusion in dry eye patients. Am J Ophthalmol. 2003;135:704-705.

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16. Dursun D, Ertan A, Bilezikci B, Akova YA, Pelit A. Ocular surface changes in keratoconjunctivitis sicca with silicone punctum plug occlusion. Curr Eye Res. 2003;26:263-269.

17. Kim BM, Osmanovic SS, Edward DP. Pyogenic granulomas after silicone punctal plugs: a clinical and histopathologic study. Am J Ophthalmol. 2005;139:678-684.

18. Albietz J, Lent on LM, McLennan SG. Chronic dry eye and regression after laser in situ keratomileusis for myopia. J Cataract Refract Surg. 2004;30:675-684.

19. Yen M, Pflugfelder SC, Feuer WJ. The effect of punctal occlusion on tear production, tear clearance, and ocular surface sensation in normal subjects. Am J Ophthalmol. 2001;131:314-323.

TABLE 1

Characteristics of Patients Who Underwent Punctal Plug Placement Before Initial or Retreatment Surgery

TABLE 2

Uncorrected Visual Acuity (UCVA) Before and 1 Month After Punctal Plug Placement

10.3928/1081-597X-20070501-08

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