- Email: [email protected]
Selective Laser Trabeculoplasty
Andrew S. Gurwood, O.D.
Long-term Acyclovir Use Uchoa UB, Rexende RA, Carrasco MA, et al. Long-term acyclovir use to prevent recurrent herpes simplex virus infection. Arch Ophthalmol 2003;121:1702-4.
lowup. In the control group, 78% of the patients had a recurrence following cessation of acyclovir, with a mean time of 15.3 months. In comparison, the patients who remained on therapy had a recurrence rate of 36%, with a mean time of 37.3 months.
Herpes simplex remains a significant concern due to its recurrence rate of 20% within two years, 40% within 5 years, and 67% over 7 years. Each subsequent episode increases the risk for development of stroma1 disease and central scarring that will require eventual corneal transplantation. One of the clinically valuable lessons taken from the original Herpetic Eye Disease Study was that a prophylactic effect of oral acyclovir therapy (400 mg b.i.d.), when prescribed for 12 months after a recurrence of ocular HSV, was demonstrated. A recurrence rate of 32% appeared in the placebo-treated group in comparison to a 19% recurrence rate in the treated group over a post-treatment observation period of 6 months. Not much information has been published on these patients beyond the 1-year point of oral therapy.
Cvenkel B. One-year followup of selective laser trabeculoplasty in open-angle glaucoma. Ophthalmologica 2004;218:20-5.
These investigators performed a retrospective study on two groups of patients with a history of recurrent herpetic disease who were treated with oral acyclovir for at least 12 months. The control group (n = 18) terminated therapy and was monitored for at least 6 months while the study group (n = 22) continued treatment during fol-
For more than 20 years, the use of Argon Laser Trabeculoplasty (ALT)has provided a safe and effective means to lower intraocular pressure (IOP) in selected individuals with issues of compliance or whose condition was determined to be medically uncontrollable with topical agents. Further, results from the Glaucoma Laser Trial
With any study, there are sources of potential bias. In this case, -patients with more-severe disease were encouraged to continue therapy, while some had the option to discontinue treatment after 12 months. The overall outcome may or may not have been affected by an ineffectiveness of the acyclovir and/or a small n ~ n ~ b eofr enrolled subjects. Nevertheless, the investigators arrived at the conclusion that long-term acYcl0vir Use remains an effective option beyond 12 months for reducing the risk of ocular HSV recurrence. iMarh Sawamura, O.D.
Selective Laser Trabeculoplasty
h d r e w S- Gurwood, 0.D-
(GLT)indicated that ALT is at least as effective as medical therapy in treating newly diagnosed cases of open-angle glaucoma. Although effective, ALT does have its limitations. Selective Laser Trabeculoplasty (SLT) is a relatively recent innovation that functions like ALT, working at the cellular level of the trabecular meshwork by increasing phagocytosis and cell division, thereby improving aqueous outflow without the scarring side effects seen in ALT. However, the initial questions that must be answered are: (1)how safe is SLT? and (2) what lasting effects does it have on IOP? Recently, researchers evaluated the safety and efficacy of SLT as a treatment in individuals with medically uncontrolled (IOP > 22 mmHg) open-angle glaucoma by way of a 1-year prospective study. Treatment was defined as a 50 spot application to 180 degrees of the tra-.-
-
VOLUME 75lNUMBER 8lAUGUST 2004
OPTOMETRY
M E D I C A L ABSTRACTS
becular meshwork, with a Qswitched frequency-doubled Nd:YAG laser of 532 nm (model Trazbeculas, A.R.C. Laser) for 3 ns with a spot size of 400 ym. IOP response was measured at 1, 2, and 24 hours, then again at 1 week, 1 month, 2 months, 3 months, 6 months, 9 months, and 12 months. Safety measures included monitoring for anterior chamber reaction and IOP elevation, inspection for peripheral anterior synechiae, and the use of dexamethasone-neomycin drops four times a day for 5 days. In this study of 44 eyes, SLT yielded a decrease in IOP similar to that obtained by other TM laser studies; however, a reduced response was found at the longer followup. While at 6 months the mean IOP reduction was 4.75 mmHg (18.6%) from baseline, with 78% of eyes showing a 3 mmHg absolute reduction (results were similar to those obtained by previous studies comparing SLT to ALT), at 12 months mean IOP was 4.37 mmHg (17.1%lower),with only 62% showing an absolute reduction of 3 mmHg. Results from the GLT demonstrated a higher reduction at 12 months (9.6 mmHg), although 360 degrees of the TM was treated. Acute rise in IOP (8 mmHg) was seen in 9% of SLT-treated eyes, a figure similar to those found in reports on ALT. The only other adverse event in SLT-treated eyes was anterior chamber reaction (47%).However, associated transient IOP elevation was documented in only one of those eyes.
OPTOMETRY
The results of this study demonstrate that SLT has the potential to provide an unequivocal, repeatable alternative to ALT. In fact, it may even be more beneficial to those with previously unsuccessful ALT. Studies that concentrate on evaluating the long-term efficacy will determine if it possesses clinical superiority. Jason Price, 0 .D.
Treatment of Presumed Bacterial Corneal Ulceration Bosscha MI, van Diesel JT, Kuijper EJ, et al. The efficacy and safety of topical polymyxin B, neomycin, and gramicidin for treatment of presumed bacterial corneal ulceration. Br J Ophthalmol 2004;88:25-8.
Along with the advent of the fluoroquinolone class of topical antibiotics, bacterial corneal ulcer treatment underwent a revolution. Armed with new topical agents that are more powerful out of the bottle and with less reported resistance than fortified preparations, success rates have climbed and both patients and doctors have benefited. Recognizing that a larger armamentarium could only serve to improve the quality of practice, researchers in the Netherlands set out to evaluate the clinical efficacy and safety of topical polymyxin B, neomycin, and gramicidin (Polyspectran) for the treatment of suspected bacterial corneal ulceration at the Leiden University Medical Center, Leiden, The Netherlands.
Patients with a diagnosis of a suspected bacterial corneal ulcer between April 1995 and February 2002 were retrospectively identified and reviewed; clinical and microbiological features and response to therapy were analyzed. All patients were treated with Polyspectran eye drops. In total, 91 patients were included in this analysis. Bacteriological cultures of 46 patients (51%) were positive and revealed 51 micro-organisms. Staphylococcus aureus ( 2 9 . 4 % ) and Pseudomonas aeruginosa (23.5%) were the most frequently encountered bacteria. Eighteen patients switched therapy before complete healing of the corneal ulceration; four patients were lost to followup. Of the 69 patients who completed the Polyspectran treatment, reepithelialization occurred in 68 patients (99%)and (on average) took 12.6 days (median, 8 days). Among 91 patients, there were four perforations and one evisceration. Seven toxic or allergic reactions were also reported. The preponderance of evidence suggests that the combination of polymyxin B, neomycin, and gramicidin (Polyspectran)is also-like other topical medications meant to treat microbial keratopathy-an effective and safe treatment for suspected cases of bacterial corneal ulceration. Whether it will surface as a potential addition to the U.S. arsenal is, at this time, unknown. Andrew S. Gurwood, O.D.
VOLUME 75lNUMBER 8lAUGUST 2 0 0 4
Long-term Acyclovir Use Uchoa UB, Rexende RA, Carrasco MA, et al. Long-term acyclovir use to prevent recurrent herpes simplex virus infection. Arch Ophthalmol 2003;121:1702-4.
lowup. In the control group, 78% of the patients had a recurrence following cessation of acyclovir, with a mean time of 15.3 months. In comparison, the patients who remained on therapy had a recurrence rate of 36%, with a mean time of 37.3 months.
Herpes simplex remains a significant concern due to its recurrence rate of 20% within two years, 40% within 5 years, and 67% over 7 years. Each subsequent episode increases the risk for development of stroma1 disease and central scarring that will require eventual corneal transplantation. One of the clinically valuable lessons taken from the original Herpetic Eye Disease Study was that a prophylactic effect of oral acyclovir therapy (400 mg b.i.d.), when prescribed for 12 months after a recurrence of ocular HSV, was demonstrated. A recurrence rate of 32% appeared in the placebo-treated group in comparison to a 19% recurrence rate in the treated group over a post-treatment observation period of 6 months. Not much information has been published on these patients beyond the 1-year point of oral therapy.
Cvenkel B. One-year followup of selective laser trabeculoplasty in open-angle glaucoma. Ophthalmologica 2004;218:20-5.
These investigators performed a retrospective study on two groups of patients with a history of recurrent herpetic disease who were treated with oral acyclovir for at least 12 months. The control group (n = 18) terminated therapy and was monitored for at least 6 months while the study group (n = 22) continued treatment during fol-
For more than 20 years, the use of Argon Laser Trabeculoplasty (ALT)has provided a safe and effective means to lower intraocular pressure (IOP) in selected individuals with issues of compliance or whose condition was determined to be medically uncontrollable with topical agents. Further, results from the Glaucoma Laser Trial
With any study, there are sources of potential bias. In this case, -patients with more-severe disease were encouraged to continue therapy, while some had the option to discontinue treatment after 12 months. The overall outcome may or may not have been affected by an ineffectiveness of the acyclovir and/or a small n ~ n ~ b eofr enrolled subjects. Nevertheless, the investigators arrived at the conclusion that long-term acYcl0vir Use remains an effective option beyond 12 months for reducing the risk of ocular HSV recurrence. iMarh Sawamura, O.D.
Selective Laser Trabeculoplasty
h d r e w S- Gurwood, 0.D-
(GLT)indicated that ALT is at least as effective as medical therapy in treating newly diagnosed cases of open-angle glaucoma. Although effective, ALT does have its limitations. Selective Laser Trabeculoplasty (SLT) is a relatively recent innovation that functions like ALT, working at the cellular level of the trabecular meshwork by increasing phagocytosis and cell division, thereby improving aqueous outflow without the scarring side effects seen in ALT. However, the initial questions that must be answered are: (1)how safe is SLT? and (2) what lasting effects does it have on IOP? Recently, researchers evaluated the safety and efficacy of SLT as a treatment in individuals with medically uncontrolled (IOP > 22 mmHg) open-angle glaucoma by way of a 1-year prospective study. Treatment was defined as a 50 spot application to 180 degrees of the tra-.-
-
VOLUME 75lNUMBER 8lAUGUST 2004
OPTOMETRY
M E D I C A L ABSTRACTS
becular meshwork, with a Qswitched frequency-doubled Nd:YAG laser of 532 nm (model Trazbeculas, A.R.C. Laser) for 3 ns with a spot size of 400 ym. IOP response was measured at 1, 2, and 24 hours, then again at 1 week, 1 month, 2 months, 3 months, 6 months, 9 months, and 12 months. Safety measures included monitoring for anterior chamber reaction and IOP elevation, inspection for peripheral anterior synechiae, and the use of dexamethasone-neomycin drops four times a day for 5 days. In this study of 44 eyes, SLT yielded a decrease in IOP similar to that obtained by other TM laser studies; however, a reduced response was found at the longer followup. While at 6 months the mean IOP reduction was 4.75 mmHg (18.6%) from baseline, with 78% of eyes showing a 3 mmHg absolute reduction (results were similar to those obtained by previous studies comparing SLT to ALT), at 12 months mean IOP was 4.37 mmHg (17.1%lower),with only 62% showing an absolute reduction of 3 mmHg. Results from the GLT demonstrated a higher reduction at 12 months (9.6 mmHg), although 360 degrees of the TM was treated. Acute rise in IOP (8 mmHg) was seen in 9% of SLT-treated eyes, a figure similar to those found in reports on ALT. The only other adverse event in SLT-treated eyes was anterior chamber reaction (47%).However, associated transient IOP elevation was documented in only one of those eyes.
OPTOMETRY
The results of this study demonstrate that SLT has the potential to provide an unequivocal, repeatable alternative to ALT. In fact, it may even be more beneficial to those with previously unsuccessful ALT. Studies that concentrate on evaluating the long-term efficacy will determine if it possesses clinical superiority. Jason Price, 0 .D.
Treatment of Presumed Bacterial Corneal Ulceration Bosscha MI, van Diesel JT, Kuijper EJ, et al. The efficacy and safety of topical polymyxin B, neomycin, and gramicidin for treatment of presumed bacterial corneal ulceration. Br J Ophthalmol 2004;88:25-8.
Along with the advent of the fluoroquinolone class of topical antibiotics, bacterial corneal ulcer treatment underwent a revolution. Armed with new topical agents that are more powerful out of the bottle and with less reported resistance than fortified preparations, success rates have climbed and both patients and doctors have benefited. Recognizing that a larger armamentarium could only serve to improve the quality of practice, researchers in the Netherlands set out to evaluate the clinical efficacy and safety of topical polymyxin B, neomycin, and gramicidin (Polyspectran) for the treatment of suspected bacterial corneal ulceration at the Leiden University Medical Center, Leiden, The Netherlands.
Patients with a diagnosis of a suspected bacterial corneal ulcer between April 1995 and February 2002 were retrospectively identified and reviewed; clinical and microbiological features and response to therapy were analyzed. All patients were treated with Polyspectran eye drops. In total, 91 patients were included in this analysis. Bacteriological cultures of 46 patients (51%) were positive and revealed 51 micro-organisms. Staphylococcus aureus ( 2 9 . 4 % ) and Pseudomonas aeruginosa (23.5%) were the most frequently encountered bacteria. Eighteen patients switched therapy before complete healing of the corneal ulceration; four patients were lost to followup. Of the 69 patients who completed the Polyspectran treatment, reepithelialization occurred in 68 patients (99%)and (on average) took 12.6 days (median, 8 days). Among 91 patients, there were four perforations and one evisceration. Seven toxic or allergic reactions were also reported. The preponderance of evidence suggests that the combination of polymyxin B, neomycin, and gramicidin (Polyspectran)is also-like other topical medications meant to treat microbial keratopathy-an effective and safe treatment for suspected cases of bacterial corneal ulceration. Whether it will surface as a potential addition to the U.S. arsenal is, at this time, unknown. Andrew S. Gurwood, O.D.
VOLUME 75lNUMBER 8lAUGUST 2 0 0 4